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Tuning your subs

How to make the bass in your car sound its best

In this article... I'll show you how to tune your amplifier to get your subwoofers to sound just the way you want them to. Just follow these simple steps for great bass:

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.

Before we get started...

If you are looking for information about buying subwoofers, please read our Subwoofer Buying Guide and check out our selection of top-rated subwoofers, then come back here to learn more about setting them up to deliver great sound.

First, set your speaker level

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 you power your full-range car speakers with an amplifier, it is crucial that the amp's gain is properly set to prevent distortion.

[Need an amplifier? See our full selection.]


Step 1: Remove the 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: Flatten the signal, open the low-pass filter

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 stereo. 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: Adjust the subwoofer gain and low-pass filter

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.

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: Bass boost and subsonic filter

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.

For ported subwoofers, use a subsonic filter on your amplifier to tame any overly loud low notes. This will help decrease the levels of the notes at which the enclosure resonates. Fine-tune all the filters 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 subwoofer's volume down as far as you can, using the subwoofer level in the receiver's sound adjustment menu or the remote bass knob if you have one.

Blending all the frequencies

Now that each piece of the puzzle is set, it's time to bring all the music into focus.

Step 5: Matching the subwoofer level to the receiver volume

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

Match sub level

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.

Troubleshooting any problems

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.

You shouldn't lower the gain of your full-range amplifier to try and match your lack of subwoofer volume. Doing so could allow the amp to send out distorted, clipped signals to your full-range speakers, defeating your goal for 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 about sound tuning

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.

Last updated 2/8/2022
  • LARRY FREEMAN from Sparks

    Posted on 7/6/2022

    What an excellent tutorial on setting gains and adjustments! I wish I had found this article sooner! Thank you!!

  • Pablo Montero from Miami

    Posted on 6/9/2022

    Remote bass control knobs basically act as the gain control when connected, the sub amp gain must be set with the remote know either disconnected or turned all the way up, otherwise you may end up turning the gain over the distortion point when actually listening to music. I also disagree with step 3. Setting the gain on the sub amp to right below distortion while the head output is not even close to the distortion point is not a good idea. You will end up with an overly sensitive sub amp that will allow the system to distort when turning the sub volume up in step 5. Ideally you should be able to turn the sub all the way up without distortion, even if that means the sub being to loud in relation to the rest of the speakers.

  • Jay from Bloomfield

    Posted on 4/25/2022

    I bought a JBL probassSL2 how would you tune the enclosure Sub has a Xrossover settings , level settings and a bass settings . My head unit has a sub out no fancy setting just simple all my adjustments will be straight from the sub enclosure

    Commenter image

    Buck Pomerantz from Crutchfield

    on 4/26/2022

    Jay, If re-reading this how-to article doesn't help, maybe you should hire a professional installer.
  • John from Austin

    Posted on 4/22/2022

    Step 1 states "The amp gain is now set" Step 2 then tells me to "Turn your sub amp's gain to its lowest, most counter-clockwise position" I didn't mark the position of Gain in Step 1, never seem to return Gain to that position, etc What is the purpose of Step 1?

    Commenter image

    Buck Pomerantz from Crutchfield

    on 4/22/2022

    John, Step 1 describes setting the receiver output and full-range amp gain to achieve the maximum volume they can go to and still play cleanly. After setting that, you'll leave the amp gain set and control the volume with the receiver's volume control only. Step 2 describes how to add good bass sound to the system.
  • Dillon from Lititz

    Posted on 4/5/2022

    Just curious on an issue I ran into recently. I have a rockville slim dual 12 sub with the build in amplifier. To create a RCA input for the sub amp I am using a AudioControl LC2I Pro. Everything in the system was running fine until the other day when I started the system, the bass was hitting obnoxiously hard from the subwoofer. This random issue of what I thought to be something overpowering the sub in turn caused the amp to heat up very rapidly and cause distortion at mid level volume. Also after noticing the issue I went to retune and readjust the amp and LOC. Upon some initial adjustments I also noticed the sub was playing quite loud even with the gain setting at a minimum on the sub amp. Somehow I have it sounding decent now, but if there is an electrical issue I would love to know. Please let me know what you think of the situation or if you need more info. I have a 2007 Honda CRV with the gear mentioned above installed.

    Commenter image

    Buck Pomerantz from Crutchfield

    on 4/6/2022

    Dillon, It sounds like you have a loose connection or a malfunctioning amp or LOC. It'll take a bit more troubleshooting in order to identify the problem. If you bought any of your gear from Crutchfield, you could call Tech Support for free help.
  • Tyler Moyer from Jacksonville

    Posted on 3/16/2022

    When you say "Turn up the receiver's volume to its maximum, distortion-free position. Then slowly turn up the subwoofer volume until the bass sounds balanced with the rest of the music. That should do it." Are you referring to "subwoofer volume" as in the receiver, amp, or bass knob (if the system has one)

    Commenter image

    Buck Pomerantz from Crutchfield

    on 3/17/2022

    Tyler, In this case, the sub level in the receiver's menu is the adjustment used. A sub amp's gain setting optimizes the signal for the sub amp to play at full volume, which is usually way too loud for the rest of the system. The remote will fine-tune the sub level for different songs or social situations.
  • Alexa from Beaverton

    Posted on 3/8/2022

    I'm not sure if someone has already pointed this out but in Step 2. above you write: "Turn your sub amp's gain to its lowest, MOST COUNTER-CLOCKWISE position." I have a a Pioneer GM-D7400M. The farthest position to the left puts the gain at it's HIGHEST setting: 6.5v. The lowest setting is clockwise, to the right, at .2v. So unless I'm missing something, your generalization, "most counterclockwise position," is confusing.

    Commenter image

    Buck Pomerantz from Crutchfield

    on 3/9/2022

    Alexa, The labelling of a gain control's settings are rather counter-intuitive. When the gain is set to its lowest setting, the input is at its highest - so, for instance your amp's gain will be set lowest when the input voltage is highest, around 6.5V. When the gain is properly set at its highest setting, the input'll be only around 0.2V. The best way to set gain is to ignore the confusing setting labels. That's why we only describe turning controls clockwise or counter-clockwise.
  • Theodore Ulrichsen from Georgetown

    Posted on 2/27/2022

    I have a cxa 360 Amp with 2 10inch kickers. Do I run both rca cords to Amp from head unit? I'm only using Amp to power the 2 subs..

    Commenter image

    Buck Pomerantz from Crutchfield

    on 2/28/2022

    Theodore, I don't know how you have your 4-channel amplifier running two subs of unknown impedance and power ratings - but you'll need as many RCA cables as the number of channels your amp is using.
  • Brad Watson from Wesson

    Posted on 2/22/2022

    I have the kicker compRT 10" 2 ohm downfire In small box in 06 f-150 super crew under driver side rear seat with a kicker 400.1 amp im having trouble burning the sub? I don't hear distortion I want it to hit as hard as it can hit I have factory radio any help would be greatly appreciated

    Commenter image

    Buck Pomerantz from Crutchfield

    on 2/23/2022

    Brad, That amp and sub are well-matched for power and impedance. Any burn you're smelling from the sub is probably due to it being over-driven - either by trying to get more bass volume out of it than it can deliver, or being mounted in an inappropriately sized enclosure.
  • Colby McDaniel from Sylvester

    Posted on 1/25/2022

    I have 2 shallow mount VD-12 skars 800wt peak 500 rms pared with a skar 1500wt monoblock and I'm having trouble setting the amp to get clear hard bass with no clipping any advice

    Commenter image

    Buck Pomerantz from Crutchfield

    on 1/26/2022

    Colby, Without knowing exactly what amplifier you have, it's difficult to say, but I think either your subs are wired together incorrectly for the amp to handle, or the amp is just too powerful for those subs.

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