Contact us
Close contact box
Connect ID #
164 219 614 3
Connect ID #
164 219 614 3
All finished with your chat session?

We’ll email you a transcript of this conversation for your records.

All of our representatives are
currently chatting with other customers.

Please enter your name.  
Please enter a valid email address. Why is this required?
Please enter your US phone number.  

For Tech Support, call 1-888-292-2575

Thank you, !
Our conversation will be emailed to
Advisor Image

Your Advisor,

More about me
Please enter a question  
Don't wait on hold. We'll call you back when it's your turn to talk with the next available .
Please enter your name  
Please enter your phone number  

Please enter a message  

Calls may be recorded for training and quality control purposes.

We are located in Virginia USA.

How to set amplifier gain using test tones

When the hum turns into a buzz, it's clipping

Buck in the Crutchfield Labs

Buck in the Crutchfield Labs

In an amplified car system, you need to set your amplifier’s gain correctly in order to enjoy your music’s full range of dynamics and frequency response — hearing all the notes clearly, whether loud or soft. You’ll feel your music’s impact better and hear exciting details that otherwise would get lost in your car.

There're quite a few ways to set gain, but I think listening to test tones is the simplest method giving the best results. Continue reading the article if you want to see how I came to this conclusion by my researching the issue in the Crutchfield Labs.

Instructions for setting amp gain using test tones
  1. Download 0 dB sine wave test tones of 40, 100, 400, 800, and 1000 Hz to your preferred medium (disc, chip, file, phone).
  2. Set your receiver’s EQ presets and the amp’s bass boost to the way you normally listen to your music.
  3. With the amp gain at minimum, play the 40 Hz tone and turn up the receiver’s volume until you hear it buzz. Back off the volume until the hum returns, and write down or mark the volume setting.
  4. Repeat Step 2, noting the top clean volume settings, using the 100, 400, 800, and 1K Hz tones.
  5. Pick the tone with the lowest clean volume setting and play it again at that setting.
  6. Raise the amp’s gain until you hear it buzz, back off until it hums, and you’re done.

Setting the gain by playing music

The quick and easy way to set the gain is by ear while playing music.

Most manufacturers recommend playing familiar music with the amp gain low, raising the receiver's volume until the music distorts, then backing it off until the music sounds clean again. Next, you turn up the amp's gain until you hear the distortion again, then back it off slightly, and you're done.

For a more detailed explanation, see my article about Tuning your subwoofers.

Setting the gain using test tones

The other methods of setting gain involve using test tones. A test tone is a single note played at a specific frequency, and is typically found on a level-setting disc, but can also be found online for downloading. In the Crutchfield Labs, I ran a set of tests and determined that "doing it by ear and music" works, but not quite as accurately or scientifically as using test tones.

1. Test tones and oscilloscope

Each tone creates a reference-level (0 dB) sine wave that you can observe on an oscilloscope screen. Instead of listening for distortion in music. As you adjust the volume and gain, you can see exactly at what point the signal of each frequency distorts and where it plays clean.

Waveform image

An example of a a clean waveform (left) and a distorted, clipped wave (right)

2. Test tones and speakers

But seeing as most people don’t have oscilloscopes, I thought that maybe by listening to the tones through speakers, one could also set an amplifier’s gain correctly. A non-distorted sine wave test tone sounds like a pure hum. When it distorts, you can clearly hear it buzz. By using test tones played through a speaker, I wondered how accurately I could set an amp’s gain as compared to setting it by the other methods.

A deep dive into my Crutchfield Labs project

I went into The Crutchfield Labs and set up an amplifier, wired to a power supply, a car receiver, and a pair of speakers. I also attached two sets of probes to a pair of speaker wires, one going to a voltage meter and the other to an oscilloscope. This way, we could see what the sounds look like and read the resulting power level the amp produced.

Pioneer DEH-3400UB CD receiver

Pioneer DEH-3400UB CD receiver

First set the tone controls to the way you listen

The receiver's and amp’s EQ and crossovers needed to be set to where they normally would be when playing music. This is so the gain would be set under real-world conditions. Adding boost, at any frequency, after setting the gain, can make the amp clip, distorting the sound and endangering speakers and subs.

I let the receiver (a Pioneer DEH-3400UB) stay in its factory preset "Dynamic" EQ setting, which boosts the bass and treble for a fuller sound. That meant certain frequencies would play louder than others. I needed to find out which tone clipped the receiver first, at the lowest volume setting. Then, I needed to use that receiver volume setting at that tone’s frequency to set the amp’s gain.

Part 1: Setting the gain with the oscilloscope

How loud can the receiver play and still play clean?

I started with the amp’s gain set to its minimum, and the speakers disconnected. I played the first tone, 40 Hz, a low bass note, only fit for subwoofers, and set the scope to view the sine wave. Then I turned up the receiver’s volume until I could see something bizarre happening to the wave’s shape. It didn’t "clip" at the top and bottom, it distorted in the middle. But I could see exactly at what volume level the distortion first appeared, and where it disappeared.

I took note of what the receiver’s volume reading was: 52. (The receiver’s top volume number was 62.) That meant the receiver played 40 Hz clean and at its loudest at its "52" volume.

Test Tone CD Track 7 40 Hz Maximum Clean Volume = 52
Test Tone CD Track 8 100 Hz Maximum Clean Volume = 51
Test Tone CD Track 9 400 Hz Maximum Clean Volume = 57
Test Tone CD Track 10 1K Hz Maximum Clean Volume = 59
Test Tone CD Track 11 4K Hz Maximum Clean Volume = 56
Test Tone CD Track 12 8K Hz Maximum Clean Volume = 55

This receiver plays loudest at volume 51, otherwise 100 Hz notes would clip

I measured the receiver’s distortion-free top volumes for the other test tones on the disc. The 100 Hz tone stood out as the strongest — I had to turn the volume to its lowest setting to get it to play clean. Because that volume represented the level that all the tones would play cleanly through the receiver, I used the 51 setting for the receiver’s volume for the next step. Because the 100 Hz tone was the strongest, and would clip the amp first, I used the 100 Hz test tone to set the amp's gain.

Sound Ordnance amplifier

Sound Ordnance M-4050 4-channel amplifier

The amplifier’s turn

I played the tone and looked at the sine wave while turning up the amplifier’s gain knob. Any waveform distortion I then saw came from the amp, not the receiver. Turning the gain back down until the distortion disappeared, I set the gain exactly where the amp and receiver were both at their maximum clean output levels: perfectly gain-matched.

Setting the gain right optimizes the amp’s output

I turned up the gain to the amp’s top clean-playing point and read the volt meter. The volt meter read AC (alternating current) voltage, and the amp I used (a Sound Ordnance M-4050 4-channel) showed a top clean output for 100 Hz of 17.6 VAC. That translated to about 77 watts. Not bad for an amp rated at 50 watts RMS per channel.

Bench testing results in higher power readings

What was going on was the power supply the receiver and amp used was 13.5 volts DC, about the same as a running car’s system usually provides, but the amp wasn't connected to the speakers and so wasn't loading down the power supply with the increased current demand of the speakers. That explained some of the "extra" power. But the amp definitely performed above its specified rating. If I had wanted to, I could have set the amp’s output to exactly 50 watts, by turning the gain down until the voltage read a targeted number, in this case 14.14 volts AC.

Math formulas — skip this paragraph

The wattage equals the voltage squared divided by the speaker’s impedance in ohms, 4 ohms in most cases. The voltage equals the square-root of the product of the wattage times the speaker’s impedance (also usually 4). 50 watts times 4 ohms equals 200; the square-root of which is 14.14 volts AC. 14.14 volts through 4 ohms of impedance creates 50 watts of power. These formulae are based on Ohm’s and Joule’s Laws and you can’t break them if you tried.

A note on multimeter accuracy

To accurately measure your amplifier’s output power with a multimeter, use a 60 Hz tone for a subwoofer amp, and a 100 Hz tone for a full-range amp with its high-pass filter turned off.

  • This is because most meters are made to measure AC voltage accurately at 50-60 Hz (the common frequency of all power systems around the world). Using a standard hand-held multimeter to measure the voltage of a higher-frequency signal results in readings that are much lower and leads to inaccurate power calculations.
  • For instance, the Amprobe 15XP-B multimeter I used in this Labs demonstration reads the voltage of a 0 dB 1 KHz signal about one-fifth the level that it reads at 40 Hz or 100 Hz. This would result in a calculated wattage about one-twentieth of the correct output power.
  • Different meters will have different degrees of deviation.

Kenwood KFC-6984PS 6"x9" 4-way speakers

Kenwood KFC-6984PS 6"x9" speakers

Part 2: Setting the gain using speakers and my ears

The noisy part of the test

I then repeated the whole performance with one speaker connected — a Kenwood KFC-6984PS 6"x9" 4-way. I want to say, in advance, that this was not a pleasant experience. Two hours later, my ears were still painfully ringing from the very high 8K Hz tone. Jordan, also in the Labs area at the time, complained that the 4K Hz tone was still ringing in his. This method can produce high-pitched, annoying, ear-drilling sounds that could hurt your hearing if you expose yourself for too long, and definitely will bother everyone within listening distance.

For using tones and your ears to set an amp’s gain, I recommend sticking with only the 40, 100, 400, or 1K Hz tones. They don't hurt at all. The 100 Hz tone alone will do for both subwoofer and full-range speaker amps.

Speaker hum
Speaker buzz

When a hum starts to buzz

A sine wave sounds like a hum. When it distorts, you can clearly hear it buzz. Again, the 100 Hz tone was the first to buzz, and at the exact same 51 volume setting. With the receiver at that top distortion-free level, I played the tone again and turned up the amp’s gain until I could hear the tone buzz again. Then I backed it off until the hum alone remained. The place the gain knob was set and the voltage readings were exactly the same as it had been using the scope.

I did this test after working hours so no one else would be disturbed. But I proved to myself, at least, that the ear-and-tone method worked just as well and as accurately as using a scope. The 40 Hz tone couldn't really be reproduced by the speakers, so was useless. The 100 Hz tone rattled everything on the desk, so it was a little difficult to pick the buzz-point out of the crowd of reverberations. The 400 Hz tone was the best tone to detect clip-points, with a very clearly defined hum-to-buzz point.

I hear music

Finally, I tried music and my ears alone. I performed this test twice, days apart, and also afterhours. Not everyone wants to hear my songs played loudly over and over again. At first, I played a favorite R&B-type song full of percussion, bass, horns, and lots of production — but I couldn’t hear it distort, only get loud. So I switched to a clear-voiced female vocalist singing swing. I also played a male singer, to see if it would be any different — it wasn’t.

Your hearing gets more acute when you close your eyes

I closed my eyes when I did this test, so no numbers were used to set the receiver’s top volume. I turned it up until I heard something go wrong with the vocal — it seemed thinner, not as bell-like, and harsher. The male singer's voice suddenly developed a rasp. After turning the receiver down a little, restoring the fine quality of the singer’s voice, I turned up the amp gain until I heard the same thing.

The two times I did this test, I got two different results. The first time, the receiver's maximum volume setting ended up one notch below the tones and scope setting. The second time, it was one notch higher than the tones and scope setting. But both times, the amp gain setting was exactly the same as the other methods.

The differences can’t be heard

On the first day, setting it by ear and music alone, I ended up thinking I should never turn the receiver higher than 50, and the gain was set so that at that 50 volume, the amp put out 15.7 VAC at 100 Hz, or 62 watts. On the second day, it ended up that I could turn it up to 52, and get 18.8 VAC at 100 Hz, or 88 watts. That 100 Hz tone was indeed slightly distorted visually, but it wasn't audible in the music. Plus, I don't usually listen to music full-blast for very long periods of time, so in real use, I would likely never be able to hear the difference.

It’s all about the music

I think either I was a little more or less sensitive to the singers’ voices on different days, and noticed changes at different levels than I could see in the waveforms’ shapes, or the music CDs I used were recorded at a different reference levels. I certainly cranked some swing those evenings in the Crutchfield Lab.

Whatever the differences between the methods were, they all resulted in having the receiver and amp properly gain-matched, and loud, distortion-free music ensued. Using the test tones disc was easier than listening to music. even without the oscilloscope, the tones made it possible for me accurately set the gain. It was very easy to discern when the hum distorted into a buzz.

Download some test tone files or pick up a test tone disc and try if for yourself!

  • Chris from Independence

    Posted on 12/4/2020

    I used 1K Hz and 40 Hz test tones to adjust my gains and when I'm listening to my music I still hear my speakers crackle and my speakers buzz, but if I turn on my headlights to turns into a hum noise.

    Buck Pomerantz from Crutchfield

    on 12/7/2020

    Chris, Crackling and buzzing, especially that change when the lights are on, are usually caused by a loose ground or power connection.
  • JohnR from austin

    Posted on 11/13/2020

    Is simply rotating the gain knob to the voltage location that matches the head unit output voltage an accurate way to set it?

    Buck Pomerantz from Crutchfield

    on 11/16/2020

    John, No. The graphics printed on the chassis are approximations of where to set the knob.
  • JohnR from Austin

    Posted on 11/13/2020

    How do you prevent the other speakers in the car from not playing the test tone? It seems like they would just be going crazy as you do the test to set the gain, any way to mitigate this?

    Buck Pomerantz from Crutchfield

    on 11/16/2020

    John, Each gain knob controls two channels - left and right - so setting gain with a pair of speakers playing is probably the beat way to go. If you want only one speaker to play, use the balance and fade controls of the receiver to send the sound where you want.
  • Cristhian from Florida

    Posted on 10/23/2020

    When tuning the amps do you have the filters off? Or put them on after you do the gain settings with the sine waves? I have a Jeep Wrangler with a Pioneer nex5200. I plan on using the tones recommended and finding the highest volume possible without clipping on the 4 speakers the Jeep brings(with no amp). Then once I get that volume, I will tune two amps I have in the back of the Jeep (one amp drives 4 speakers in the box and the other amp drives 2 subs). I'm guessing I will be using the tone that clipped the fastest while setting the head unit audio correct? Probably 100hz like mentioned. So I'll use the 100hz and tune both. Do I put filters on the amps before tuning with the 100hz or after? Since I think the subs will prob Be around 70-80hz LP, the mids 100hz HP and the tweeters 1.5k HP. Thank you.

    Buck Pomerantz from Crutchfield

    on 10/23/2020

    Christhian, Disengage the amp's filters for these steps.
  • Natasha Renee Clark from Laramie

    Posted on 10/20/2020

    Oh and I have the two 12inch MTX Terminator subs in a box whats a good amp?

    Buck Pomerantz from Crutchfield

    on 10/20/2020

    Natasha, Give us a call so an Advisor can help you match an amp to your subs.
  • Natasha Renee Clark from Laramie

    Posted on 10/20/2020

    Wheres a good ground connection In the trunk?

    Buck Pomerantz from Crutchfield

    on 10/20/2020

    Natasha, That's impossible to tell without at least knowing what kind of vehicle you have.
  • Eyvindur Nikulasson from Nerlandsøy

    Posted on 9/24/2020

    So are we talking db or dbfs tones? Where are people downloading these tones from?

    Buck Pomerantz from Crutchfield

    on 9/24/2020

    Eyvindur, A signal strength of 0 dB for analog and 0 dBFS for digital pretty much describe the same thing - the standard top line level (0.775 VAC for analog signals) used for electronic devices. Do an online search for downloadable test tones and you'll find dozens of free examples of test tones to download and use.
  • Denis from Cuernavaca

    Posted on 8/24/2020

    QUESTION: Please help. I want the voltage on the speaker output to be 23 V. I am using a 1k test tone. Source volume is at 75% (from a Clarion pre-amp EQ). Stereo volume is at 75% as well. I turned up the gain on the amp and it never went past 10V. What is wrong????

    Buck Pomerantz from Crutchfield

    on 8/24/2020

    Denis, You are experiencing the exact reason why we don't recommend using a multimeter to set amp gain, they're inaccurate at the frequencies involved. The above article contains the full explanation: Meters are made to measure AC voltage accurately at 50-60 Hz (the common frequency of all power systems around the world). Using a standard hand-held multimeter to measure the voltage of a higher-frequency signal results in readings that are much lower and leads to inaccurate power calculations. To accurately measure your amplifier's output power with a multimeter, use a 60 Hz tone for a subwoofer amp, and a 100 Hz tone for a full-range amp with its high-pass filter turned off.
  • Raynau from South africa

    Posted on 8/13/2020

    Hi i have a rockford p3 2ohm dvc and a infinity 1600a monoblock amp push 600rms at 2ohm can u please tell were must i put the gain and also how big must my seald ancloser be it seems like mind is to small because when i turn my bass frequensy up i hear no deferents but when i had n ported enclosure i can hear the diferents in bass frequency when i turn it up

  • Ariel Schmeisser from Santiago

    Posted on 5/27/2020

    Al the sine wave tones you need are in spotify. Even pinknoise, phased and de-phased. It was a nice discovery!

  • Francis Jansz from Huntingdale 3166 Vi

    Posted on 4/6/2020

    My JBL 2402 tweeters was replaced with new Diaphragms I am Try amping with a all tube Lucman 3 Way Active Crossover and use a 211 Power out Valve amp for my tweeters 16 Watts class a per channel my tweeters volume is very low even with my years very close to it how can I improve the gain onu tweeters

  • Ryan from Mount Vernon

    Posted on 12/30/2019

    I followed your guide blew a $150 speaker. I would recommend setting gains to music, not tones, with a flat EQ.

  • Kevin from Augusta

    Posted on 4/18/2019

    Should the head unit be left at factory settings when setting the gains and finding out the max clean volume? And also should the subwoofer be turned off when finding out the max clean volume level that your head unit clips at?

    Buck Pomerantz from Crutchfield

    on 4/18/2019

    Kevin, You should set your receiver's EQ and the amp's bass boost to the way you normally listen to your music, before finding maximum clean volume and setting amp gain.
  • Brent from Bradenton

    Posted on 3/18/2019

    One question, where do you have the receiver volume at for the amplifier portion of the test? Do you leave it at the same max level as you just found? If I do that there's no headroom left the turn up amplifier gain at all. I imagine you have to bring the receiver volume back down somewhere to have headroom to bring the gain up.

    Buck Pomerantz from Crutchfield

    on 3/18/2019

    Brent, Do not lower the receiver volume before setting amp gain. Doing so will virtually guarantee your amp will clip the signal when the receiver's volume is turned up later. You should leave the receiver set at its maximum clean output in order to achieve optimum amp gain setting.
  • Keene from Waterloo

    Posted on 2/25/2019

    Thanks for the great info this will be very helpful for setting up my amps! I noticed you talk about setting the gain at minimum while figuring out the HU clipping volumes but where would the amp's crossover be set during three processes? Thanks for sharing your knowledge!

    Buck Pomerantz from Crutchfield

    on 2/25/2019

    Keene, To start off, the amp crossover filters should be set to "off" or "full range." If that's not possible (filters always on), then you'd start with high-pass filters set to their lowest frequency and the low-pass filters set to their highest frequency.
  • Anthony from Pittsburgh

    Posted on 2/6/2019

    hello, Great info here. Can you use these same test tones for a home theater setup? Thanks, Anthony

    Buck Pomerantz from Crutchfield

    on 2/7/2019

    Anthony, You can certainly play test tones on your home theater, but I have never heard of a home theater receiver with a gain control, so you can't use the test tones for gain-setting.
  • Ryan from New York

    Posted on 2/5/2019

    I have a pioneer headunit and a mosconi amp, with these two level matching using DMM and test tones are a breeze, now I have changed to a JVC headunit with the same voltage preout, but the readings are way low using the same amp. With the pioneer I can get 25v from the amp easy, with the JVC it can barely reach 6v, tried a new JVC 2-din with same preout voltage, same result barely 6v output. Am I missing something? Why with the pioneer I can get correct output and not with the 2 new JVC?

    Buck Pomerantz from Crutchfield

    on 2/6/2019

    Ryan, Just because two stereos have the same output voltage rating, doesn't mean they play at the same volume. The relative setting of the volume knobs also come into play - 3/4 volume on one unit might not match the other. And remember, DMMs only accurately measure AC signals round 60 Hz, so they're not the best tool to set amp gains with.
  • Monty Miller from Covington

    Posted on 12/17/2018

    Where is the best place to download dependable 0 Db test tones. Also if you know of a CD that has 0 Db test tones.

    Buck Pomerantz from Crutchfield

    on 12/17/2018

    Monty, Googling "download 0dB test tones" brings up quite a few reputable sites where you can download tones and purchase test tone CDs. It'll be up to you to pick the ones you think best.
  • Nathan Vetter from East Aurora

    Posted on 12/10/2018

    Buck, could you lend some advice my way? i installed Infinity Reference 6532ix's (coaxial) in the rear door of my 2016 Chevy truck and Infinity Reference 9630cx's (components with passivize crossovers) in the front. i am also running a kicker key 180.4 amp to power these. I followed your o-scope method to the tee. i played test tones from my phone over the Bluetooth connection and with my phone volume all the way up. i found my limiting Hz and volume level. I let the amp run it's auto tune with the gains all the way down and again using a pink noise tone over bluetooth from my phone. after the auto tune finished i try to set my gians. For some reason the front channels (or amp #1 on the key) clip 1kHz with the gian all the way down. but the rears do not. i can set the rear gains to about half way on their rotation. the resulting in cab sound is so rear heavy i cant help to think i am doing something wrong. i tried to re-do the entire process with the volume level output on my phone at the "normal" level (about 3/4 on its scale and where the phone automatically sets it when first connecting to a Bluetooth device). i was able to get some more range with the gains but when you switch from the Bluetooth single to a radio the volume of the radio blows you away. This cant be right either. What am i doing wrong?

    Buck Pomerantz from Crutchfield

    on 12/10/2018

    Nathan, It is my understanding that if you use the Auto Setup process for your Key 180.4, you leave the amp gain at minimum and the program automatically sets gain, balance, fade, time-alignment, high-pass filters, and EQ optimized for the front seat position or wherever you put the Setup mic. When you change settings on the amp after setup, you're undoing all the good tuning the amp automatically made. Set the gain and filters of your amp with either the method outlined in this article, or by the Auto Setup process, but not both.
  • Mr. Whites from Philadelphia

    Posted on 12/7/2018

    If you think it's the speakers than that's pretty disappointing - especially at $400 a pair. Do you have any experience with these speakers (Morel Tempo Ultra Components)? I bought them from Crutchfield. If they can't perform as well as others I might be swapping these for something else. How long is Crutchfield's return policy? Are other 5 1/4" speakers able to reproduce 80hz -3db sine waves without distorting at 35% HU volume? Care to recommend any? Thanks Buck! Morel T

    Buck Pomerantz from Crutchfield

    on 12/7/2018

    Mr, I didn't mean to imply that there was anything wrong with your speakers, just that you should use a higher frequency test tone (like 500 or 1000 Hz) to set the amp gain. I don't know of any 5-1/4" speaker that can play bass tones very well, in spite of their specifications. That's why subwoofers exist - to provide the bass that regular speaker can't play. In fact, I often recommend installing Bass Blockers to protect small speakers from damaging bass signals.
  • Mr. Whites from Philadelphia

    Posted on 12/3/2018

    Great read - Thank you for the info! I tried using the "test tones by ear" method in my setup however, and didn't get very far. In trying to find the maximum HU volume, my full-range components (Morel Tempo Ultra 5 1/4") began buzzing at a much lower HU volume than normal everyday listening volume - I'm talking normal person listening volume... not "car audio enthusiast" volume haha. Using -3db sine waves in the 60- 100hz range, my woofers began buzzing at approx 35% HU volume. Surely these speakers should be able to take about 35% of HU volume with no eq boosts and the amp gains turned down. In addition, I also have my HU's HPF set to 80hz with an -18db cutoff slope so they aren't even running "full range". So what gives? Why would I be getting a distortion buzz at such low HU volume? Are sine wave test tones in the 60-100hz range not appropriate for testing full range speakers using the "test tones by ear" method? Logically it seems appropriate since theres lots of activity going on in that frequency range, normally played at higher levels than 35% HU volume. Any insight would be greatly appreciated. The equipment chain in question is ... HU - Pioneer AVH-1440NEX (No "Bass Boost" or eq boosts - HPF @80hz w/ -18db Cutoff slope) Amp - Alpine PDR-V75 (gains set low - no "Bass boost" or HPF applied) Speakers - Morel Tempo Ultra 5 1/4" Components Thank you for your time and for sharing your knowledge!

    Buck Pomerantz from Crutchfield

    on 12/4/2018

    Mr, It sounds like your speakers can't handle the test tones you're using sending them very well. Try using midrange tones, like 500 or 1000 Hz, instead of bass and mid-bass tones. You'll probably get better results.
  • Brandon from Charleston

    Posted on 7/31/2018

    After further testing, I've discovered it's only the right midrange woofer making the noise, but the strange part is that I'm not sure it's distortion. It almost sounds like a faint telephone beep tone. I swapped that speaker's wires to the left crossover, which is run by channel one, to rule that out. The issue persisted. I disconnected all other speakers to make sure it wasn't a polarity issue, but issue persisted. Played the left driver and the tone was gone. What the heck is going on? Maybe that one speaker wire is picking up noise somewhere in the car? Seems strange since both channel's wire is run side by side on the passenger side.

    Buck Pomerantz from Crutchfield

    on 8/4/2018

    Brandon, If you bought your gear from Crutchfield, you could call Tech Support for free help troubleshooting your system. Their toll-free number would be on your invoice. If you purchased your equipment elsewhere, you can still get expert Crutchfield Tech Support - 90 days-worth for only $30. Click on this link for details.
  • Brandon from Charleston

    Posted on 7/31/2018

    I used test tones to set my amp gain for my component speakers. I'm a little confused and frustrated. At 100 hz, 800 hz, and even 8,000 hz, I can turn the gain to about 3 o'clock before I hear any change/distortion. However, at 1000 hz, I can only get to about 30% on the dial before a very noticable buzz. What gives?? It's a focal amp, 70 watts rms x 2, and it's pushing morel maximo 6 components.

  • Butch from Montgomery Vlg MD

    Posted on 7/5/2018

    Thank you for your response, Buck. I will try the 100Hz tone (maybe the others too) for both the 4channel Pioneer GM 8604 and the SSL LoPro10 sub. I don't detect distortion from my camry 2016 head unit even at full blast (with amp turned down) so I tune at 75% volume. Maybe using your method, I will finally get the best of my PolkDB6502s and my 70RMS rear 6x9 kickers. My problem is that I want it to sound as clear and clean as my home sound system, which is really impossible. I really appreciate the clear response (perhaps dumbed-down for me, thank goodness) and the informative article. Sincerely appreciated.

  • Butch from Montgomery Vlg MD

    Posted on 6/29/2018

    So using test tones and listening to them through the car speakers does NOT damage the speakers? I may have read somewhere that it is safer to disconnect the speaker wires from the amp. Can you shed some light on this please? And thank you for the article. Quite informative.

    Buck Pomerantz from Crutchfield

    on 6/29/2018

    Butch, I think you're referring to an amp gain setting technique that uses a volt meter to attain a target output voltage that matches the desired output wattage. I do not recommend that way of setting gain because it doesn't take into account whether or not the source is clipping, nor the accuracy of the meter at any frequency besides 60 Hz. Playing a distorting tone loudly might eventually damage a speaker, but not for the short time needed to set an amp's gain.
  • Eric Olmos from Bellflower

    Posted on 6/8/2018

    I have a alpine cde-149bt head unit connected to a three.2 eq to epicenter then xd 1000 watt jl audio using a 40hz test tone on a oscilloscope and the frequency the o-scope shows is about 160hz ?? Any particular reason it would read that? Thank i need to connect the amp wires in series??

    Buck Pomerantz from Crutchfield

    on 6/9/2018

    Eric, Either your system is creating a second harmonic overtone, or you're misreading the scale on your oscilloscope's screen.
  • Buck Pomerantz from Crutchfield

    Posted on 5/16/2018

    Matthew, Perhaps checking out our Tuning your subs article will shed some light on the subject. It's no secret - a low-pass crossover removes high-frequency content from a subwoofer, and a high-pass crossover removes low-frequency content from midrange speakers and tweeters. When in doubt, start at 100 Hz and then tweak to taste.

  • matthew from Pensacola

    Posted on 5/16/2018

    Nice article but for some reason, every single article I've read regarding amp tuning, ( I've read dozens of them from many different websites) every single one leaves out a key factor and I can't for the life of me figure out why it gets left out or why no one ever seems to ask. Maybe it's just me I'm not sure, very well could be. My question is, where do you set the crossover on the amp when setting gains since every single person who makes a tutorial neglects to mention it. Perhaps it isn't important at all whatsoever since it's never mentioned. Perhaps it's an industry secret that isn't suppose to be talked about to those who don't already know about it. Think Fight Club. Regardless, can someone please please pretty please tell me once and for all what I'm suppose to do with the crossover on my amp when playing test tones to set my gains. I promise to never speak of it to anyone ever. I will guard the secret with my life I swear. Plz and thank you.

  • Jimmy

    Posted on 5/8/2018

    Great info. question what test tone do u recommend for sub woofer, coaxial and component speakers. Also what crossover setting do u recommended setting them all too. Current setup: infinity 475a amp - 4x75rms to 2x alpine coaxial 75rms rear, 2x alpine component speakers 75rms front and infinity 1600a amp - 400rms to single pioneer sub 400rms. Thanks

  • Dominic M. from New Jersey

    Posted on 4/2/2018

    Fair enough, can you please tell me which oscilloscope you used during your tests?

  • Buck Pomerantz from Crutchfield

    Posted on 3/31/2018

    Dominic, I really don't know enough about test gear to make any recommendations for an oscilloscope.

  • Dominic M. from New Jersey

    Posted on 3/28/2018

    Hello Buck, Great article and information. Thanks for taking the time to answer everyones questions. Can you give some suggestions on Oscilloscopes such as types, brands, models? I see many decent priced Oscilloscopes on ebay but want to make sure I get the correct one.

  • Buck Pomerantz from Crutchfield

    Posted on 3/9/2018

    John, Multimeters read RMS voltage. So attaining an output of 30 volts RMS through a 2-ohm load produces 450 watts RMS. You can measure the signal's peak-to-peak voltage with your scope, as well as see when it clips. The only harm you can do to a sub by playing a 50 Hz tone is if you play it too loud. If your amplifier is rated higher than your sub, setting gain with an oscilloscope won't work - the sub's sound will distort before the amplified waveform shows any distortion at all.

  • John

    Posted on 3/8/2018

    When setting the gain of my amp I'm targeting 30Vp-p for a 450W output on my 2ohm sub. The gain setting for my amp to get 30V on my multimeter gives me about 80V on my scope. This must be due to the low input impedance of the scope giving unrealistic output from the amp. I don't have a dummy 2 ohm load rated for that kind of power. Is it okay to play a 50 Hz test tone on my actual sub or will I damage it? I figure a reading with the scope under the actual load is the best way to optimize the power output of the amp. My amp rating is higher than my sub so I want to push it as much as I can without damage. Clipping doesn't seem to be a problem for me. Thanks! John

  • Buck Pomerantz from Crutchfield

    Posted on 2/9/2018

    Thomas, Sending clipped signals to tweeters is indeed dangerous, especially if it's done for long periods of time. The short duration of the time it takes setting gain shouldn't endanger your speakers. I absolutely recommend using ear plugs when in loud noise situations. The foam kind that you fit in your ear canals lessen the volume but don't change the tone. Humming and buzzing can be clearly distinguished.

  • Thomas

    Posted on 2/6/2018

    Wouldn't this listening process carry the risk of damaging your speakers? I've heard clipping the sound will wreck your tweeters. Also, would hearing protection inhibit your ability to accurate determine the clipping point? Your description of ringing ears from setting your gain by this method does not sound fun...

  • Buck Pomerantz from Crutchfield

    Posted on 2/2/2018

    Brian, The spikes you see are probably more an artifice of your oscilloscope's response-time than the clipped signal's harmonic radiation. Clipped signals, as you noticed, don't always take the form of a square wave. What you're also witnessing is the fact that your gear clips different frequencies at different levels. Find out which frequency at which the receiver first clips and use that frequency tone to set your amp gains. For example, if your receiver clips 4k Hz at a lower volume setting than any other signal, you'd use that tone to set amp gains. Also, the amp gains should be re-set after any EQ or tone adjustments are applied.

  • Brian K. from Houston

    Posted on 2/1/2018

    So I've been messing around with my oscilloscope to set the gains on two amps.. my head unit is a pioneer AVH X2800bs 4 channel pioneer GM D8604 JL Audio j2 500.1 monoblock When I isolate the head unit I'm checking the max output through the rca cables with a 0dB test tone suite I made.. once I found the max receiver volume at 0dB I disconnected all speakers and plugged the rca pre-amps back in. What is interesting to me is the 4channel amp when playing a test tone at max unclipped rca output does not form a square wave but starts to spike in the center with what looks like harmonic destabilizing centered around the wave peak which if gain is further increases shows the expected flat top however it still contains a sharp spike at the start and end of the square peak. Could this just be an artifact of class d amplifiers? Also when I set 1kHz to max unclipped amplification then check 4kHz and 8Khz the higher frequencies show "sine like" waveforms but the shape is somewhat distorted ... and even when maxed out on the gain the 4-8kHz don't show up as a flat topped wave but rapidly spike the voltage and appear completely garbled.. So to much question... should I be setting the gain based on the 1kHz signal or let the higher frequencies set the ceiling?

  • Buck Pomerantz from Crutchfield

    Posted on 11/2/2017

    Dann, The owner's manual for that amplifier is a bit confusing as to the actual function of the remote - whether it adjusts the amp's input gain or output level. I think you're right to treat it as a gain knob and set the amp gain with it set to maximum for just the reasons you stated.

  • Dann Combs from Colorado Springs, CO

    Posted on 11/2/2017

    Thanks Buck. I've read versions of these approaches at least two dozen times in my quest to educate myself but yours is the most clear and concise. Well written. I do have one question though. How do I incorporate remote level control on the amp (SoundStream PN1.650D) in this process? This amp has a gain control, a bass boost control, and an external remote level control. I am not going to use the 45 Hz bass boost and will just leave that dialed all the way down to minimum. I have an oscilloscope and understand the process. But I've seen no advice regarding the remote control. Is that simply another gain control knob? Or is it in some way different from the gain control dial on the amp? If it's just another gain control then my inclination is to set it to the max and leave it there, setting the on amp dial to minimum and turning the on amp dial up until I find clipping, backing it off to the clean signal point and leave it there permanently. Then, while playing music I could use the remote knob to turn down the bass to desired levels, knowing that I could not worry about turning it up to max if desired. Is that the right approach? Or what is recommended for working with both the gain dial and the remote knob in the gain setting process? Thanks again.

  • Buck Pomerantz from Crutchfield

    Posted on 9/27/2017

    Glennon, Not knowing exactly what amplifier you have makes it impossible to give advice on how to wire subs to it. If you want a question answered about a system, you must identify your equipment by brand names and model numbers. Mixing differently voiced subs in a system together often results in less than-ideal-sounding bass.

  • glennon heinrich from macedon

    Posted on 9/26/2017

    Okay so I've been running 2 Infinity Kappa 100.9 W's in a sealed box with passive radiators tune to 27 Hertz and it sounds phenomenal at 600 RMS each even though they're rated for like 375. I've since switched the speakers to 4 ohm to introduce a 2 ohm load and then I wired in a 12 inch earthquake dbxi in parallel to bring it back to a 1 ohm load. And now it doesn't sound nearly as good but an R&B it's definitely louder and shakes everything more. Could that be because the 12 is in a sealed box would it sound better if I get that box tuned to the same frequency as the other. Thanks P. S. In the pr enclosure those subs take 600 watts RMS all the way down to 12 Hertz then you start to get mechanical noise I've only done it once lol.

  • Buck Pomerantz from Crutchfield

    Posted on 9/11/2017

    Brian, Finding the maximum clean volume of your receiver is unaffected by the amplifier's gain setting. I don't know which receiver you have, but you should set its subwoofer output as you would the gain - turn it up until it distorts, then lower it until it's clean. Two subwoofers that can get wired together to form a 4-ohm load cannot be rewired to form a 2-ohm load - that's impossible.

  • Brian from Bay Area

    Posted on 9/7/2017

    Hey Buck, fantastic article! I can wait to try all this stuff out next week. Couple things: When you're determining your HU's max clean volume, your gains at that point are at the minimum, right? If you were to have the gain somewhere else but still on the lower end, (say 10% or 20%), would the distortion point on the HU vary in any way? Also, if I want to leave some room to play with for my subs, I'm assuming I should set the HU's sub control to its max or at least whatever number I want to use as my max when setting the gain, correct? And lastly, which is better? Running two 500 RMS subs at 4 Ohms with an amp that puts out a max of 1100 at 4 Ohms, or the same two subs at 2 Ohms where the same amp puts out 2000 at 2 Ohms? Is the amp working harder in the first scenario vs the second? Thanks!

  • Buck Pomerantz from Crutchfield

    Posted on 7/10/2017

    Kevin, You can adjust the subwoofer volume to balance in with the full-range speakers by either lowering the subwoofer level of the receiver or with the sub amp's gain.

  • Kevin from Bristol

    Posted on 7/9/2017

    One of my amps is 4 x 75w rms but my sub amp is 1 x 550w rms, setting the amps gains by ear with test tones will result in the sub output being a lot louder than the 4 channel amp ? So once gains are set, do you then reduce the sub amp gain until it sounds matched with the lower power amplifier ?

  • Buck Pomerantz from Crutchfield

    Posted on 6/22/2017

    Ashay, Yes, that's the way to proceed. Find the receiver's highest clean volume, then the LOC's, and then the amp's.

  • Ashay Borkar from Goa,India

    Posted on 6/22/2017

    Hello Buck ! Very informative article How do I set my 4 channel Scosche LOC gains connected to a 4 channel amp which is connected to 2 speakers and bridged to a sub? My car has a stock head unit . Should I check the whole process on head unit first then the loc and then the amp? Thank you

  • Buck Pomerantz from Crutchfield

    Posted on 6/12/2017

    Pete, That sounds right to me. Set the receiver to its maximum distortion-free level, the AudioControl device to its, and then the amp's gain as well. The instructions for the LC7i say that its gain should be set high and the amp's set low.

  • Pete from Woodinville, WA

    Posted on 6/10/2017

    Buck, I have an LC7i in my system taking the stock headunit speaker level outputs to line levels. I'm assuming I would need to set the gain on the LC7i at a very low level as well as my amp gains to a low level to figure out the factory head unit's maximums, then go to the LC7i, set it's maximum and finally go to the amp and set it's gains. Is that correct?

  • Buck Pomerantz from Crutchfield

    Posted on 5/3/2017

    Cody, The misuse of low-pas filters (HPF) and bass boosts lead to the destruction of many subwoofers. Both are equalizers used to optimize the tone of the bass sound. A low-pass filter gets engaged to remove the high-frequency notes you don't want the sub to play. Turning it "all the way up" is not the proper way to set it. Check out Tuning your subs for that. A bass boost gets engaged when you want to emphasize the lowest bass notes, around the low E of a bass guitar or piano. If you like the tone when using a bass boost, you must readjust the amp's gain control to compensate for the boost in over-all volume and ensure that no dangerous distortion ever plays. Achieving full power in an amplifier depends on setting the gain correctly, not on the tone of the bass signal.

  • Cody from Scott AFB

    Posted on 5/2/2017

    Sir/Ma'am, So I have an Orion Step to 122d 12" sub rated 1500 RMS and an Orion amp 1500 RMS and i fried a sub after it was professuonally tuned.... So basically to tune properly the LPF needs to be all the way up along with the volume at the proper level then adjust the gain till it clips/distorts/buzzes right? So what's the purpose of having bass boost? Basically I want to push all 1500 RMS or close to it but not sure you could do that without bass boost. Also, I have a yellow top batt ran to my primary and my amp ran to the yellow top so it has a standalone battery all for itself.

  • Buck Pomerantz from Crutchfield

    Posted on 2/15/2017

    Cory, Using a manufacturer's claimed ratings to set amp gain by voltage sometimes results in a mis-set situation which could endanger speakers. Setting gain to just below the clipping point, whether ascertained audibly or visually, ensures maximum signal headroom and minimum noise floor. A lot of people set their amp gains to just above clipping, to achieve higher levels of sound.

  • cory from long beach

    Posted on 2/14/2017

    I have read some tutorials stating that you should only use the scope and test tone to set the gain up to the voltage calculated by the units actual power and the 4 ohms, and not the clipping point. the difference being that the former is the manufacturers recommended limit for "stable" power, and though there may be headroom between that number and the clipping point (your extra found power), it was not necessarily stable there... do you have any insight on that?

  • Buck Pomerantz from Crutchfield

    Posted on 1/11/2017

    Pascal, I don't recommend using a multi-meter to set an amplifier's gain because it'll only read voltage accurately around 60 Hz and can't tell you if the signal's clipped or not. For instance, that Amprobe meter's specs claim 1% AC voltage accuracy only from 45 to 400 Hz. A less expensive solution would be to get a pair of noise-reducing earplugs that'll protect your hearing while still allowing you to hear test tones humming and buzzing.

  • Pascal from Boston

    Posted on 1/11/2017

    If I don't wish to use my ears to set an amp gain -- sensitivity issue -- and I don't have the funds for an oscilloscope, would it make a difference if I bought a True RMS multimeter (such as the Fluke 115 or Amprobe AM-530) vs a regular cheap multimeter to set my amp gains for accuracy?

  • Buck Pomerantz from Crutchfield

    Posted on 1/4/2017

    Shannon, Thank you - it's heartening to hear that there are actual readers out there. I'll let you in on a little writer's secret. I keep a document with a bunch of stock answers to those frequently repeated questions saved, so all I have to do is copy and paste them when needed. Especially for those who leave comments on multiple articles I wrote.

  • Shannon

    Posted on 1/3/2017

    Hey Buck are you tired yet of giving the same answer over and over? Maybe I am abnormal but I actually read the article before questions or comments...ha ha...smh

  • Buck Pomerantz from Crutchfield

    Posted on 1/3/2017

    James, I don't recommend using a multi-meter to set an amplifier's gain because it'll only read voltage accurately around 60 Hz (maybe 40-100 Hz) and can't tell you if the signal's clipped or not. This is why I do recommend using test tones and your ears to set gain accurately.

  • James

    Posted on 1/3/2017

    A lot on online videos about setting amp gain reference using 40Hz and 1kHz test tones with your everyday multimeter. Does the statement about using a 100Hz test tone for setting the gain on full-range amps still apply? Is it more accurate than using a 1kHz test tone? Thnx

  • Buck Pomerantz from Crutchfield

    Posted on 11/17/2016

    Adam, If you want to squeeze every last watt you can out of your system and don't mind a little distortion, use -5dB test tones. Using the lower-level signal means you'll set the amp gain a bit higher than you would with 0dB tones. However, it's safer using 0dB tones to set gain.

  • Adam from Gothenburg

    Posted on 11/17/2016

    I cant use cd's on my stereo, so im going to download some tones and play them via usb and the use a oscillioscope. But i wonder what level the tones should be, -0db, -5db and so on. I've done some searching on the web but everyone says different

  • Buck Pomerantz from Crutchfield

    Posted on 10/17/2016

    Brent, It'll work either way, but most people prefer setting amp gain quietly, with the speakers disconnected, if possible. If you do set gain via test tones and an oscilloscope with the speakers connected, you will be able to hear as well as see when the amp clips.

  • Brent from Denver

    Posted on 10/16/2016

    When looking at the tones of the Amp with an Oscilloscope do I hook up the Scope to the speaker output with no speaker attached?

  • Buck Pomerantz from Crutchfield

    Posted on 9/19/2016

    Tendai, The gremlin's in your multi-meter - it's only accurate at 60 Hz. And you didn't say what the impedance of your subs are. 20 volts AC through a 2-ohm sub, for instance, generates 200 watts RMS. Another complication that you might not be aware of is that the impedance of a speaker or sub changes with different frequencies, and its output power does as well. Trying to set amp gain using an inaccurate meter reading the voltage of different frequencies through an unknown impedance will not work very well. If you have an oscilloscope, use that to set your amp gains, it will result in a more accurate setting.

  • Tendai from Derby

    Posted on 9/19/2016

    Hi again Buck Thanks for that. I'd purchased a DSO 112 O'scope which was en route when I asked. I've since hooked it up to the amp and set the gain using 1000Hz tone for the mids and 40/50 tones for the 8 inch woofers cutting the gain to about 10% before clipping. That said I then went on to check the output voltages after all had been set with lovely sine waves on the scope. Strangely channels 1 and 2 show voltages of 17.5 and 16.5 even though I set them both to high pass at the same level (180 as per mfr). Stranger still channels 3 and 4 which are for the woofers low passed at (100Hz as per Mosconi) show voltages of 20-21 without any sign of distortion. Is there a family of gremlins in the amp?

  • Buck Pomerantz from Crutchfield

    Posted on 9/12/2016

    Tendai, I don't recommend using a multi-meter to set an amp's gain because it'll only read voltage accurately around 60 Hz and can't tell you if the signal's clipped or not. Using test tones and your ears means it doesn't matter what an amp or receiver's visual display or markings show while setting gains. But the answer to your question is that to put out 100 watts RMS through a 3-ohm load takes 17.3 AC volts RMS.

  • Tendai from Derby, UK

    Posted on 9/10/2016

    Hi Buck Great article. Still a bit confused. I have a Mosconi 130.4 DSP amp rated at 130RMS per channel at 4 ohms or 175RMS at 2 ohms. My speakers are Gladen 201 3 way with 4x150/100 rating at 3 ohms in a BMW E60 UK spec with 2 channels being 8 inch subs and 2 channels feeding doorcard midbases plus tweeters via a crossover. I take the 100 to be the nominal rating in that? What target voltage would you recommend if I were to use a DMM? I've tried setting by ear but the E60 BMW does not have a visual for the volume so it's difficult to tell when one has hit 3/4 volume etc etc plus the buttons can be pressed til time immemorial without one having the foggiest whether you've hit the top, mid-top, somewhere-top, not-so-top etc

  • Buck Pomerantz from Crutchfield

    Posted on 8/15/2016

    Anthony, Any test tone will very clearly change its sound from a hum to a buzz when it clips. You can hear it even when wearing ear plugs for protection. For setting a subwoofer amplifier's gain, you can use a 40 or a 60 Hz tone.

  • Anthony from Lake elmo

    Posted on 8/14/2016

    When I'm setting the amp gain for my sub's?, what test tone frequency should I use to most easily distinguish clipping and distortion? I have trouble hearing clipping and distortion playing music, there doesn't seem to be much even with gain at 3/4 and db at half

  • Buck Pomerantz from Crutchfield

    Posted on 8/2/2016

    Kenyon, Test tones and oscilloscopes are commonly used to set gains in audio equipment - a device's input sensitivity to the output of a preceding device in a system. You can download "0-dB" test tones for free from the internet - a web search will turn up a vast selection. After downloading, you can burn them to a CD or store them onto a thumb drive for playing later. You then use the oscilloscope to visualize the tone as a sine wave - when the sine wave distorts, it means the signal's clipping and the gain needs to be reduced. I can't think of any reason to use test tones and an oscilloscope to set an equalizer or a crossover, however. For those, people often use pink noise and an RTA (real-time analyzer).

  • Kenyon Cody from TX

    Posted on 8/2/2016

    So using a oscilloscope what type of cd should I I use to set EQs line drivers processors etc, also what would I look for while setting them? And if I use a oscilloscope to test tone the crossovers should I test the amps along with it first so the amps are at their full potentional before the crossovers? Thank you!

  • Buck Pomerantz from Crutchfield

    Posted on 7/25/2016

    Donavon, You should set your amp's gain with all EQs and boosts set as you would normally listen to music. Applying some bass boost after setting the gain, for example, will result in clipping. Using test tones and a multimeter to set amp gain will only work if the meter is accurate at the test tone's frequency - that's why I recommend using speakers and your ears.

  • donavon locklear from raleigh

    Posted on 7/24/2016

    Hello just purchased a jl audio w6v3, been trying to get the gain set right for a week now using a multimeter. When using a multimeter do I need to set the gain with you eq being how I listen to it? Or turn everything off?

  • Buck Pomerantz from Crutchfield

    Posted on 7/20/2016

    Nazri, Once the amplifier gain is set, in a system, it should remain untouched, no matter what volume your speakers play. When a speaker gets replaced, then the gain should be re-set to ensure that the new speaker doesn't distort.

  • nazri from malaysia

    Posted on 7/20/2016

    Do we need to change the gain level setting each time we change the speaker or we can just used the current that we already set?

  • Buck Pomerantz from Crutchfield

    Posted on 6/7/2016

    Roger, The circuitry of an amplifier uses its power supply's DC (direct current) voltage as the primary building block of its output. Along the way, power flows through the circuit's transisters, inductors, and capacitors that have the ability to boost the subsequent AC (alternating current) output. It's through the magic of each manufacturer's design that it's done.

  • Roger from Chicago

    Posted on 6/3/2016

    Some confusion. How can you get 17.2V RMS on 13.5 DC power supply? Were you measuring peak-to peak? Does your amp has boost power supply to get 17.2 V RMS?

  • Buck Pomerantz from Crutchfield

    Posted on 5/2/2016

    Tiny, You can download test tones for free from the internet - a web search will turn up a vast selection. After downloading, you can burn them to a CD or store them onto a thumb drive for playing later.

  • Tiny from Charlotte

    Posted on 4/30/2016

    Where can I buy a test tone cd?

  • Buck Pomerantz from Crutchfield

    Posted on 4/8/2016

    Zack, A subwoofer voice coil presents an inductive load, not a resistive load, to an amplifier's output - so measuring a coil's DC resistance with a multimeter won't accurately tell you its impedance. A coil's impedance actually changes according to the frequency of the signal played. Using the manufacturer's "nominal" impedance rating will bring the best results. Just be sure, when setting the gain, that your source is at its highest level with no clipping and your multimeter is accurate at the frequency of the tone you use. Most meters only read accurate AC RMS voltage around 60 Hz. (PS: producing 300 watts through a 2-ohm load takes 24.5 volts.)

  • Zack from Euless

    Posted on 4/8/2016

    I plan on setting my gain using a multimeter and calculating the max volts I should see for my sub. The reason is that I have a 12" DVC sub wired in parallel that can handle 300 watts RMS, but the Alpine amp powering it can put out 500 watts RMS in 2-ohm mode. So I need to calculate how many volts 300 watts RMS is, then set the gain to that level. In doing my math, should I first test the positive/negative speaker lead to the sub to get the exact ohms for my calculation? Or is just going with 2-ohms okay? I'm just concerned that different subs/speaker runs may introduce resistance variation, and I'm trying to be accurate.

  • Buck Pomerantz from Crutchfield

    Posted on 4/3/2016

    Ray, There are a few short-falls to using multimeter readings to set gain, instead of your ears. 1) The receiver's output may not be set to its maximum level short of distortion. 2) Your amplifier may not really put out 50 watts RMS into a 4-ohm load. 3) The speakers may be presenting 8-ohm loads to the amp. 4) Your multimeter's AC volts RMS readings may not be accurate at the frequency tone you're using.

  • Ray from Phoenix

    Posted on 4/3/2016

    If i turn my gain all the way up and the voltage is only half of my target number, what can be the problem? I get up to 7 but ohms law calls for 14.14. Its a 50Wx4 RMS. Great article by the way!

  • Buck Pomerantz from Crutchfield

    Posted on 1/11/2016

    Douglas, You should adjust and set every gain control that your amplifiers have. If a gain controls the input sensitivity of a single subwoofer channel, then you've set gain for one device. But most car amplifier gains control pairs of channels - like left-right or front-rear - so you adjust the gains for two speakers at once.

  • Douglas menchu from Austin

    Posted on 1/9/2016

    I have a question, To set the gain properly after I have set eq and bass. Do I do each speaker individually by going to front left, FR,RL,RR? Or as a pair, front then rear or all together? My front speakers are component with crossover.100 rms Rear speaker is full range. 100 rms One single sub in back.100 rms

  • Jake from Phoenix, AZ

    Posted on 12/7/2015

    Extremely helpful!

  • Hayden

    Posted on 11/27/2015

    Can't find the test tone disc. Is it at 0db or -10db?

  • Buck Pomerantz from Crutchfield

    Posted on 11/20/2015

    Thomas, Just because a receiver's spec states it can put out a 4-volt preamp signal doesn't mean the signal is clean at that level. That's why I recommend using your ears to set an amplifier's gain, so you can hear distortion when it occurs. And yes, like the article says: "Set the receiver's EQ presets and the amp's bass boost to the way you normally listen to your music" before setting the gain.

  • thomas from Garden Grove

    Posted on 11/20/2015

    My head unit preout is 4V and my 4-ch amp gain setting is 4V at full counter-clockwise and 150mV at full clockwise. Does this mean I leave my amp gain at the lowest setting (4V)? Also, I have an EQ on the head unit, do I set this to my preference before I set my gain?

  • Buck Pomerantz from Crutchfield

    Posted on 10/21/2015

    Jack, Setting an amplifier's gain with test tones and a multimeter is one of the three methods delineated in this article, and not necessarily the most accurate. It does not take into account whether the source signal is clipped or not. Personally, I think using test tones and listening for the buzz is an easier and more accurate method for setting an amp's gain.

  • Jack S.

    Posted on 10/19/2015

    Thank you so much for all the great information. I have read that I'm okay with headroom on an amp's RMS output being higher than the speakers' RMS handling. But should I always set the amplifier's output to the proper voltage for my speakers using Ohm's/Joule's Laws?

  • Buck Pomerantz from Crutchfield

    Posted on 8/25/2015

    Ken, You might have your voltage and wattage a bit confused. Wattage equals the voltage squared divided by the sub's impedance in ohms. If you read that your amplifier's putting out 44 volts AC RMS, it means that it's outputting 968 watts into that 2-ohm subwoofer.

  • Ken Lacy from Baxter

    Posted on 8/24/2015

    Please help? I have installed a Pyle 5 channel amp 6800 watts into a chevy cruze.. Powering an alpine 12" sub rated for 1000 rms. Power from Batt measures 14.2 at the amp. ground is good from the amp to the frame. 17ft rca's from the stock head unit with a pac AAGM-44 adapter to give me the rca outputs. Everything is brand new. All settings on hu and amp set to minimum or 0 - volume at 75%. I play the 50hz sounds and my multimeter starts at 6 volts and i turn the gain all the way up and the highest voltage i get is 44. I have two other gain adjusters for the other 4 channels and the highest reading i get on either of them is 42. My 2 ohm sub calls for 48 watts. Everything I read from others doing it, they can get the readings up over 60 watts and gain not even turned up all the way. Any ideas why I am getting less than normal wattage readings?

  • Chad Barkla from Australia

    Posted on 8/4/2015

    Great detailed article. Now i realise why my system sounded like rubbish when i set amp gains with receiver full tilt and no test tone Cd. Cheers

  • dominicmonastra from Clifton heights pa

    Posted on 7/1/2015

    This really helped me in so many ways !!!