Tuning your subs

How to make the bass in your car sound its best


Buck Pomerantz

Buck Pomerantz was born and raised in Philadelphia. His parents bought their first television set when he was born. He figured out how to run it by the time he was two. Besides athletics, his formative interests included electronics, amateur radio, music, and stage crew work. He got his BA in writing from Brown University. Then he joined a rock 'n roll band as their soundman and moved to Charlottesville, Virginia. After that venture failed, he spent time in Boston, New Orleans, and Berkeley. He worked in a music store in Austin manufacturing, installing, repairing, and operating sound systems for recording studios, clubs, and bands. He moved back to Charlottesville, ran a little recording studio and finally joined Crutchfield as a copywriter. He has 2 grown children and 3 grandchildren, but after a good nap he can still rock out.

More from Buck Pomerantz

sub & amp

A pair of Kenwood subs in a Sound Ordnance enclosure

One of the things I like most about subwoofers is that I can feel the musical emotion directly with my body. The low frequency beat often forces me to dance around, or, at the very least, nod my head along with the rhythm. That's why we all like music in the first place — it moves us.

It can take a little time and effort to get the exact bass sound you want from your subs, but the rewards of a well-tuned subwoofer system are overwhelmingly cool and physically satisfying.

First, set your speaker level

Step 1
Keep in mind, distortion is the enemy: it destroys speakers, subs, and eardrums. Distortion sounds like crackling, flapping, crunching, or hissing that interferes with the distinct sound of a musical instrument. If your full-range car speakers are run by an amplifier, it is crucial that that amp's gain is properly set to prevent distortion.

With the amp gain set low, play some music and turn up your receiver's volume until you hear the music distorting; then back off the volume until the music sounds clean again. Note or mark where the receiver's volume is. This setting is the maximum volume your receiver can go to and still play cleanly.

Now, turn the amp's gain up until you hear distortion again; then back off the gain slightly until the distortion goes away. The amp gain is now set, so you can lower the receiver volume to a more comfortable level. Even if your speaker system does not have an amplifier, you still need to find that maximum volume point on your receiver by turning it up to just below distortion level.

Now you're ready for some bass

Step 2
Turn your sub amp's gain to its lowest, most counter-clockwise position. Switch its low-pass filter on and set it as high, clockwise, as it will go. If it has a bass boost, turn it off. If it has a remote level control, set it to its middle position so, later, you have the choice of boosting or cutting the bass on an individual song.

Adjust your receiver's bass tone control to its middle, zero, or "flat" setting, whichever it's called on your model. If it has a subwoofer level control, set it, also, to its middle, or "no gain" setting. Sometimes receivers have a crossover, low-pass filter, or bass boost on their subwoofer output. Make sure those are all turned off, too.

First, turn the gain down

Start by turning the gain down, and turn off your filters and bass boost.

Note: Do not use the low-pass filters, crossovers, or bass boosts on the receiver and the amplifier at the same time — use one or the other, but not both. The reason is that something called phase distortion generates around each filter or boost's crossover frequency, muddying up the sound.

Step 3
Play music through your receiver at about one-quarter volume. Turn up the gain of the subwoofer amp until the sound from your subwoofer completely overpowers the other speakers, without distorting.

Turn the gain up

Turn the gain up until it distorts, then back it off until the sound is clean again.

While listening to the music coming out of your sub, slowly adjust the sub amp's low-pass filter downward until all the high- and mid-frequency notes disappear.

low-pass filter

Adjust the low-pass filter downward to eliminate high- and mid-frequency notes.

The low-pass filter eliminates the notes you don't want your subwoofer to play. It also acts like a tone control to capture the "edges" of the kick drum's sound; the attack and release of its boom. Filter out the cymbals, strings, vocals, and guitars. Leave the bass and the low drums.

Step 4
If you have a bass boost, try carefully turning it up to hear what the bass drum sounds like when you do. Applying just a little bass boost will bring up the kick a lot. Be careful with the bass boost, if you choose to use it — this is where distortion is often introduced into a system. If you hear distortion, lower the sub amp's gain until it goes away. Use the bass boost to feel the beat in the air your sub moves.

bass boost

Now play with the bass boost.

Fine-tune the low-pass filter some more to make the bass drum sound tight and dry or loose and reverberant, according to your personal taste. I like reggae and soul, so my bass is plenty loud, but it's a bit drier than most people might like. The important thing is to keep adjusting your system until you hear something you like. When you're satisfied with the tone of your system's bass and kick, turn the sub amp's gain all the way down.

Blending it all together

Step 5
Turn up the receiver's volume to its maximum, distortion-free position. Then slowly turn up the sub amp's gain until the bass sounds balanced with the rest of the music. That should do it.

Run your remote bass boost or level control up and down a little to hear what it does. Because of the size of the acoustic space in a car, subwoofers sometimes don't combine their sound constructively with the rest of a system's sound waves. If your bass has plenty of volume but seems to lack punch, you can sometimes help it by reversing your sub's speaker leads. This reverses the subwoofer cone's forward and backward movements, which might put all the sound waves together better than the other way. Whichever way sounds best is the right way.

If you hear distortion coming from your subs, turn down the sub amp's gain. If, at this point, you cannot get enough bass out of your subwoofer to keep up with the other speakers without distorting, then you will need to get a bigger subwoofer and amplifier combination, with higher power-handling abilities. Do not lower the gain of your full-range amplifier to try and match your lack of subwoofer volume. This would endanger your full-range speakers (when the amp sends out a clipped signal) without achieving the goal of clean, full sound, which is why you put in a subwoofer to begin with. More power, especially in the bass, is always better than not having enough.

Now you should be able to enjoy the robust fullness and beat of your music with your sub tuned up to match your system's capabilities and your ear's preference. Just remember to be polite, and turn your boom volume down when it might bother other people.

Learn more

For more information on how to tune your car sound stystem, see Adding a 4-Channel Amp. To learn more about getting the best sound out of your amplifier, take a look at our Amplifiers FAQ and Glossary articles.

  • Matthew W.

    Posted on 5/20/2015 3:22:39 PM

    "Note: Do not use the low-pass filters, crossovers, or bass boosts on the receiver and the amplifier at the same time - use one or the other, but not both." Great advice! This just confirms my suspicion of why the left channels of both of my BRAND NEW subwoofer amplifiers would stop playing after less than 30 seconds of being powered on. Once I disabled the bass boost and low-pass filters on the amplifiers, everything appeared to work just fine. However, I still felt that I was being short-changed because my amplifiers would only work if didn't use certain features. But just as the above article mentions, I was attempting to use the low-pass filters on both the amplifiers and the head unit. I've never been so happy to know that the issue was user error. Thank you for the confirmation.

  • Awinash Ragothaman from Durham, NC

    Posted on 6/10/2015 9:46:13 AM

    Part1: First a little insight: With all the little money I could muster, and splitting the cost of the car into monthly payments, I bought a 2005 Nissan Maxima (with aftermarket Premier radio and OEM Bose speakers) in May 2014. Music is my heart and soul and I wanted to invest in a good subwoofer and mono amp for the setup. I saved for months and bought an Alpine MRX-M55 amplifier and a Rockford Fosgate P2-1X12 loaded enclosure and had them installed at Best Buy. I was told to not play around with the gain setting as that would void the installation warranty. It was installed in a tight space and I would've had to physically remove the amp to actually get to the settings and I didn't bother doing it. I tinkered around with whatever settings I could find in the head unit but it just didn't sound right. There was this artificial boom and I had to keep changing settings for every song I heard. I initially thought it was the RF enclosure (it was ported) and bought a sealed enclosure hoping to get a bit more precision. But that didn't help either. Well, the Nissan died on me in May 2015, but I had saved up enough to get myself a brand new Hyundai Sonata Sport (touchscreen radio without Nav). I removed the Alpine and RF from the Maxima and had it reinstalled at a Best Buy in another state I moved to.

  • Awinash Ragothaman from Durham, NC

    Posted on 6/10/2015 9:46:44 AM

    Part 2: The Best Buy professional there did a great job and was kind enough to let me play around with the amp's settings. He even had it installed on the back of the seat where I could reach the settings easily. I played around with the amp's settings and was able to somewhat reach a setting that I could've grown into liking. But it still wasn't the way I wanted it: tight, repsonsive, precise and balanced. I noticed a lag between my subwoofer and the actuall song, the bass was still boomy, I could feel the bass but not hear it and lots more issues. It was then that I stumbled upon this guide. I followed it verbose and I must say, I am very VERY pleased with the outcome. I was able to get the exact same sound quality that I had dreamed of for years. I am now able to have audiophile quality sound in my car every single day. Heck, it even sounds better than my home theater. Thank you very much Crutchfield and Buck Pomerantz. Your contribution is very much appreciated.

  • Rick

    Posted on 7/20/2015 7:15:07 PM

    " Do not lower the gain of your full-range amplifier to try and match your lack of subwoofer volume. This would endanger your full-range speakers (when the amp sends out a clipped signal) without achieving the goal of clean, full sound, which is why you put in a subwoofer to begin with." This confuses me. Wouldn't lowering the gain reduce the chance of clipping?

  • Buck Pomerantz from Crutchfield

    Posted on 7/21/2015 12:26:33 PM

    Rick, The section you quote from concerns how to react to a situation where the bass is inadequate. Turning down an amp's gain indeed reduces the chance that the amp will clip the signal, but it increases the chances that a person trying for louder bass will clip the signal coming from the receiver by turning up the volume, and that could be dangerous for speakers and subs. The solution for when full-range speakers are overpowering a sub is not to turn the speakers down but to get a more powerful amp for the sub.

  • kevin Ha'aoto from Honiara,Solomon izla

    Posted on 8/18/2015 8:24:02 AM

    Hi,my name Kevin and I'm from Solomon island. Well I have a situation here which I bought an sound stream amplifier 4000 watts 1 ohm stable.then I want to use its max power rating which is 2000 RMS x 1@1 ohm. Well how many sub would you reccommend to use or how many watts sub should I use if I want to use between 2-4 sub? Awaiting your answers

  • Buck Pomerantz from Crutchfield

    Posted on 8/18/2015 11:09:57 AM

    Kevin, There are a few ways of wiring multiple subwoofers together to form a 1-ohm load so that amp can put out maximum power. You can browse through some subwoofer wiring diagrams at this link to see a good selection. One that could apply to your situation is this diagram that shows two DVC 4-ohm subs wired to a mono amp. You'd want each sub rated for between 750 and 1200 watts RMS.

  • Sam from Rockport

    Posted on 8/24/2015 2:52:56 AM

    I have no idea what you were saying in the article. The sentences and definitions used don't fit the names of the adjustments so its no good for me. I have 2 10 in subs (probox) under my back seat in my Dodge ram. Pioneer with GPS and 7" screen and a 1000 watt amp for the subs and 8oo watt amp for my 6x9s in all 4 doors. I have 2 2" tweeters in my dash. It freekin kicks but I want more sound from my doors to match my dash sound. I spent too much already but my right dash speaker comes on sometimes and don't know what's up with it. I had it replaced once but I guess it wasn't the speaker.

  • Buck Pomerantz from Crutchfield

    Posted on 8/24/2015 1:40:16 PM

    Sam, If you bought your gear at Crutchfield, you could call Tech Support for free help troubleshooting your system. Their toll-free number is 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.

  • Kyle from Shelbyville

    Posted on 8/26/2015 4:30:16 AM

    I have a 10" 4 OHM 10C104 Comp KICKER sub with a 500 watt Legacy amp. Is that the only 10" sub that I can hook up to that amp?

  • Buck Pomerantz from Crutchfield

    Posted on 8/26/2015 1:46:30 PM

    Kyle, If you're asking whether or not you can hook up a different subwoofer to your amp, then the answer is yes. If you're asking whether or not you can add a second sub to your system, the answer is maybe. It depends on the amp's capabilities and the impedance and power ratings of the subs.

  • James from Homestead

    Posted on 8/31/2015 7:00:12 PM

    Yes I have a question, what if I have my gains about 25% and I have loudness on, is it ok if loudness is on and will it do any harm to my amp and sub? I heard it's bad but when I put loudness it rattles my car a lot more but the volume is less ,I have a 1200 watt kicker amp and a 1200 watt dual comps loaded box so in total its 600 rms watts .can I use bass boost better or loudness ?

  • Carlos from San Jose

    Posted on 8/31/2015 10:57:52 PM

    what about the HPF???

  • Buck Pomerantz from Crutchfield

    Posted on 9/1/2015 12:01:41 PM

    James, There is nothing wrong with using your loudness setting or bass boost to make the bass sound the way you like. Loudness is usually employed when listening to soft music in order to improve bass and treble response, but if you like it keep it.

  • Buck Pomerantz from Crutchfield

    Posted on 9/1/2015 12:27:33 PM

    Carlos, A HPF or high-pass filter blocks low notes from getting to a speaker, so using one for a subwoofer won't do any good.

  • Randy from Missouri City

    Posted on 9/8/2015 6:44:18 PM

    Hello Buck, I am sure my questions are pretty simple and I am just over looking them. I just purchased a Alpine Type R SWR-10D4 and want to wire it into a 2ohm (I know how to do this). Now my amp is a Pioneer GM-D9601 and it is rated at 800w RMS @ 2ohm load. So on my headunit (Kenwood DDX-719) I have both a subwoofer and bass setting. I have been reading around and some say to set the SW setting to max (0-15) and leave the bass setting on 0. Which do I do here? Now with the DMM I would want to turn the gain up to a bit under 40 volts since the SWR-10D4 can handle 1000w RMS peak. correct?

  • Buck Pomerantz from Crutchfield

    Posted on 9/9/2015 12:45:27 PM

    Randy, You have a lot of different controls for your bass, The subwoofer control on your receiver lets you adjust the volume of your subwoofer for each song you play. If you think you may turn the bass up all the way sometimes, go ahead and set up your gain-setting with this set to full volume. The bass control is a tone control, a boost/cut at 100 Hz. Your amplifier also has a bass tone control, the wired remote bass boost (0-18 dB at 50 Hz). Set one or the other of these to whatever tone sounds best to you. Then, if you set the amp gain using a 60 Hz 0 dB test tone and a volt meter, a 40-volts AC RMS reading would result in a full 800-watt output into 2 ohms.

  • Randy from Missouri City

    Posted on 9/9/2015 5:59:53 PM

    Thanks for the reply. Ok so I am understanding that when I adjust my gain on the amp I should turn my (headunit) SW setting all the way up to 15 so I won't clip on different songs? (I mainly listen to Electronic Dance Music if this helps at all). I had the bass boost on my old sub, but decided to remove it this time around. Also on the headunit I have my bass frequency setting set to 50hz. It doesn't go any lower than 50hz btw. I usually use a 50hz tone, but I will use a 60hz tone and run my gain up to 39.XX volts. Now on the bass control adjusting this (0-8) it won't bring the voltage up at all on the sub and cause it to clip?

  • Buck Pomerantz from Crutchfield

    Posted on 9/10/2015 12:02:36 PM

    Randy, You can indeed clip the amp if you apply bass boost after setting the amp's gain. Set your tones, boosts, and sub level to the highest you'll ever set them, then set the gain, then lower the levels and boosts to where you'd usually set them. Now, you can be assured that any time you apply boost, the amp won't clip.

  • randy from missouri city

    Posted on 9/10/2015 12:23:11 PM

    Buck, I went ahead and bought the Oscilloscope ARM DSO Nano DSO201 so I can really tell if I am clipping. At $60 that is a steal and I know I will be using it in the future on other equipment. Thanks again for the replies.

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