What do all these dials and switches on my amp do?

This article discusses the various adjustments made when installing a car audio subwoofer amplifier. Addressing cross over adjustments, gain adjustments and Bass EQ

Estimated read time: 3 minutes 45 seconds.  Want to read later?

Hello everyone!  I’ve been meaning to write this for a long time, so sorry for the delay between posts.   At Sounds Incredible Mobile, I get plenty of customers who like to install their equipment themselves.  I’m all for that, unless they don’t know what they’re doing and they blow something up because of improper installation.  So, if you’ve got a nice amp and sub you want to install, but you’re afraid you don’t know what you’re doing as far as tuning goes, this article is for you.

So what are all these adjustments and dials on the side of the amp?  What do they do?

Side view JL Audio JX 500/1
Side view JL Audio JX 500/1


Low Pass Filter. This is the 1st thing you’re going to want to adjust. If you’ve got a car with decent sized speakers, like 6.5″ or 6×9, you’ll want to set this to about 80 hertz (lo-pass). If your head unit has built in crossovers, you want to set those at 80 hertz (hi-pass) as well. This way your interior speakers are playing 80 hertz and up, the frequencies they’re most capable of playing and your subs will be playing 80 hertz and down. This way everything is playing as efficiently as possible and each component is playing the frequencies they’re designed to play. If your speakers are smaller than that, you may want to set the cross over on the amp and head unit around 90-100 hertz to make up for what the smaller speakers can’t really reproduce. Once that is set, we can move on to gain.

Gain is not a volume knob, that’s a very important thing to remember when it comes to tuning. In fact, it’s so important, it bears repeating: gain is not a volume knob. It’s a sensitivity level adjustment.  It’s about matching the sensitivity of your deck’s subwoofer preout to the amplifier.  Let’s say you have a basic head unit with a 1.8 Volt preout.  The amplifier is not going to be as sensitive to a 1.8 Volt preout as one with a 4 Volt preout.  So you want to match the sensitivity.  Minimum on an amp gain is usually 5 Volts, Maximum is usually around .2 Volts.  Even your cheapest aftermarket head unit is usually at least around 1.2 Volts, so even then your gain should never be maxed out.

If you’re going speaker level in, you’d probably be surprised to learn you’re probably around 5 Volts, so even with a stock head unit, you shouldn’t have to crank the gains.  If it sounds like you need to, please read an earlier post about adding an amp and sub to a stock system.  If you get the wrong speakers for the source of the signal or if you have a stock amplified system, you may need to tweak a few things to get the sensitivity right.

A good rule of thumb is to never put the gain up more than 3/4, but if your deck is on the higher voltage side, less should be sufficient.  Remember, distortion is what kills subs and speakers. It’s a lot harder to hear distortion on bass than it is on interior speakers. And certain songs may distort at certain volumes while others do not, so it’s something you really have to pay attention to in order to avoid damaging your equipment. So crank the volume, put on a variety of music, and slowly bring up the gains to a point where it sounds good, but you don’t hear the subs flubbering or distorting.

Bass EQ.  What exactly is Bass EQ?  Frequencies have wavelength, a frequency of 45 hertz has a wavelength of about 25 feet.  This means in order to hear the full cycle of a 45 hertz wave, that wave has to travel a full 25 feet.  The distance from your subwoofer box and your ears is probably less than half that distance (This is why I love time correction/time alignment!).   The other issue you run into in a car environment is incidental sound waves.  That 45 hertz sound wave is not only trying to travel to the front of the cabin, but part of it is going to hit the other walls of your trunk and bounce back towards the front.  Some of these sound waves will put that 45 hertz frequency out of phase due to the timing of the sound waves.

By boosting that frequency, we help to make up for any phasing issues that may occur due to cabin design.  It helps to play around with the placement of the sub before actually turning this adjustment up.  Sometimes you have to use Bass EQ just to correct phasing issues that occur due to road noise.  This is definitely true if you find your system sounds good when you’re not moving, but your bass disappears as your drive.

Bass boost adjustments are usually tuned around 45-50 hertz on amplifiers, so they are boosting the playback of that particular frequency.  Bass Boost or Bass EQ adjustments should be done last after all other adjustments have been done and subwoofer positions have been tested as it’s really an attempt to correct for poor cabin acoustics.

The car is a tough environment for acoustical bliss, but it can be achieved with some technical understanding and some time and patience.

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  1. I got a soundstream, bass xtreme, BXA1-5000D hooked up to 2 12″ scar subwoofers in a Vented box. I somewhat have it sounding ok just not sure if I should have the digital bass machine on. It had wide, sweep, and output voltage. No clue about it. Then also the reg. Level, subsonic, LPF, and phase. Any suggestions?

    • Looking through the amp manual the Sweep is like a Q factor EQ option. You can pick what frequency you want boosted anywhere between 27 – 63 Hz. It depends on what your box is tuned to and what type of bass response you like. A lot of people like a boost around 33 Hz. Subsonic filter is good to have on for ported boxes. LPF is your low pass filter, that’s telling the subs what frequencies to play from. Usually we have our interior speakers set to 80 Hz HPF (high-pass filter). Think of it like a filter telling them to they play 80 Hz and up and then we do the same for the sub, but tell it to play 80 Hz and down. You can have overlap too, it depends how you like it blended and how sharp the frequency is cut off. Some crossovers are only 6 dB, some are 12, some let you go all the way up to 24.

  2. I have 2 12s alpine type r dual voice coil 2 ohm speakers and they came in a vented box. 35 in long by 16 in tall by 12 in wide.I’m trying to find out my tuned frequency so I can set my infrasonic crossover and low pass crossover. Its currently set at 80 hrtz and iso at 35.but I think it should sound better.I’m using a Kenwood kac 9106d monoblock rated at 2000 watts but is probably only pushing 1000 since I’m not at 14.4 volts and don’t have any extra batteries on the amp.can you tellbme what u think my box is tuned at and where I should set my two crossover s pleasr

    • Hi James,
      I don’t know what the box is tuned for, usually the manufacturer will let you know, that usually has to do the the port length and height. Usually we have the LPF set to 80 Hz and the infrasonic filter is usually an on/off setting. Sometimes it sounds better with it on with ported boxes, but all depends on the size. For the best sound quality, build a box to Alpine’s recommendation – it’s in the owner’s guide they tell you exact size/dimensions. And make sure you are running 4 gauge wire for power and ground for that amp, it should put out 1000 RMS with a final 2 ohm load.

    • Go to subbox.pro and you can punch in your box specs. You can punch in what internal net volume you want and some other info and it will give you box to build for whatever you want.i just built a ported with internal net volume of 1.50 tuned to 30hz for a single Alpine type r 12dvc and its ten times better than the sealed one I previously built.

      • Also i think the type rs reaponse goes down to 25hz so id probably turn it down maybe around 32 or 30hz and see how it sounds

  3. Hi Annie.
    i have a pioneer 12″ 400w rms 4ohm dvc sub.
    running on a jebson 5000w x 1 ohm amp….
    the amp is 4ohm compatable… but i have each of the voice coils wired in to each channel… each channel running at 160w rms @2 ohm…

    i listen to psychedelic trance and drum amd bass… generally a widevariety of music ranging from 128bpm to about 180/190 sometimes even 200 bpm…
    my sub plays all the slower songs perfectly… frequency ranges and all… but when i turn it to the faster tracks, i struggle to hear the kicks of the music but the basslines are still pretty clear.

    my amp has a couple of knobs im not to sure whhat they affect. Like the bassboost and subsonic knobs… if i turn the subsonic knob high i lose out on alot of sound.

    im running x2 sony xplod 420w 6×9’s, a sony cdx5 series frontloader that pushes 55wrms per chennel, and x2 sony xplod 230w mids for the front. A in a vauxhaul/opel corsa 1.4.

    can you give me a little insight regarding the gain, bass boost, lpf and also the subsonic knobs?… i can give u exact kodel number of the amp if need be, but i am struggling to get the right balance, especially since i listen to so much different music.

    thank you for your help!!!

    • Hey Kyle – normally we leave filters like subsonic off and bass boost off. If you need really tight accuracy you may want to change to a single voice coil 4 ohm sub or a dual 2 ohm sub wired in series to 4 ohm. If you run the amp at 4 ohms it will have less bass, but it will be tighter and more accurate and have more control over the woofer. I hope that helps!

  4. Annie,
    Thank you for your quick response however your answer is no help. The Rockford PPS4-8 are mid-bass woofers with a frequency response of 80-5KHz. Hooking these up at a low pass of 80Hz will damage them. The band pass setting on the 3/4 is a high pass. This means the 8″ mid bass woofers play at 100Hz and cut off at 200Hz. The db651 on the 1/2 channel play 200Hz and up. I’m sure your time is as valuable as mine so I will find my answers elsewhere.

    • Forgive me for not looking up the specs on your 8″ Rockford’s but regardless you didn’t READ my response carefully, that’s not what I said to do, but whatever, I was just trying to help.

  5. Hey Annie,
    I have a 2006 Mustang Gt, I will start with what I have front to back then get to my questions. I have a stock alternator installed(I do have a PA Performance true 200 amp alternator that is setting on a bench) and a 8078-109 RedTop Optima battery, Pioneer AVH-X4500BT Head unit. My doors consist of Polk db651 and Rockford PPS4-8. My rear deck consist of Polk db6501 woofer and a Rockford R1T-1 tweeter. I have two 10″ Polk db1040dvc in the trunk sealed enclosure. My main amp is a JL XD700/5v2, this amp runs my doors and my subs. I also have a Maxxsonics running just the rear deck.

    For starters, look past the brands of my pieced together set up, there are reasons why I have what I do and I’m trying to make the best of my set up. The JL has the Polk db651 on the 1/2 channel and the Rockford 8’s on the 3/4 channel. I have the switch to band pass on the 3/4 side with the crossover set at 100Hz for the 8’s. I also have the high pass set for the 1/2 side with the crossover set to 200Hz for the Polk db651’s. I’m really trying to isolate the mid bass in the doors. For the rear deck I have the Maxxsonic crossover set to high pass at about 180Hz for the db6501 and the Rockford tweeter. My sub is my biggest issue. I have the two 10’s on the sub side of the JL with the low pass filter mode set to 24db and the crossover set to 160Hz. I should also point out on the subs I’m at a 4ohm load.

    My issue,
    The two 10’s hit really nice when it comes to rap but when it comes to old rock (shooting star, Boston, Styx) there is no thump in my trunk. I tie my music into the system with bluetooth through my phone, my sound output is way different between phone and cd.

    My questions, and please answer them all.
    Why do I not have a heavy foot pedal thump in my trunk?
    Should and could I run my subs in a way other than mono with this amp to achieve a lower ohm load?
    Is there something I am missing in the settings with my head unit?
    Should I install the PA Performance alternator?
    Should I have the input voltage set to low or high with my setup?
    What do you think of my frequency of my setup?

    • Hi Trey,
      I’ll try to keep this simple because I have a little time and a few more comments to get to. Not sure about all your crossover settings, whether you’re referring to LPF or HPF in certain areas, but here is what I would recommend based on what you said. If you want to get mostly midbass out of those door speakers I would use your 5 channel the following way. Power the the Rockford 8’s in the doors as subs on the mono section of your XD700/5. You could cross those over around 100 Hz LPF. Run the rest of your highs off that amp on the 75×4 section HPF 80 Hz. 24 db is pretty sharp cut off, I would try around 6-12 instead. And then get yourself a higher powered mono amp for your subs, go for something with a regulated power supply like an Alpine PDXM6. This way you will get a lot more thump and a lot more power to the subs as they can handle 270 RMS a piece (that amp puts out 600 watts RMS at 4 ohm). And I would set the crossover on that at 80 Hz LPF. If you do all this, don’t use any crossover settings in your head unit and not sure what kind of condition your current alternator is in, but never hurts to have a high output alternator when doing a system. Input voltage – read the JL Audio owner’s manual page 14 tells you exactly how to set it, RCA’s are considered low voltage inputs (less sensitive), speaker level is higher voltage (more sensitive, gains can be lower). Hope that helps!

  6. Hey Annie lemme tell ya what I got rea quick and I’ll get to the question lol. Doors have kenwood xr1800 component speakers powered by a alpine ktp445u amp. Radio is kenwood 896. Have a jx1000 amp that’s powering a jl12w7. Drive a s10. My question is ever since I put my component speakers in some dude at the audio store messed with my settings and now my sub doesn’t really hit at all. I’m not quite sure what to do. I’m gonna reset the gain to about 40v but when I try it only gets to about 20v maxed out. So its like it’s not getting the power it need. Or something isn’t right. Its frustrating because I know my setup hits and is clean and the quality of music is great. I don’t think anything is loose because I sodder all my connections also. Any suggestions?

    • Hey Landon – I would ask the guy what he did – my guess is he was probably playing with the crossover points in the Kenwood head unit (HPF, LPF) but you want those on full range (or “Off” in the Kenwood menu) assuming you set your crossover points on the amplifiers. If you set your crossover on your amps and then went ahead and put them on the head unit too that will really mess with the sound!

  7. Hey! I was just wondering what I should set my LPF at for my amp for my set up. I have a Jl audio 12w3v3-4 and a JL XD600/1. I listen to a lot of hip hop and I’m not a pro at this stuff. Thanks!

    • 80 Hz is probably good – unless you have real small interior speakers like 4″, then I might bump it up to 100 Hz.

  8. I have 2 mtx audio 12s and s 500 watt Rockford fosgate amp and the subs are bridged. It is in a 2006 bone 325 ci with a Harmon kardon stock head unit. It is the bmw business CD player believe me this was not easy even figuring out how to install after market subwoofers due to the fact that the place I took it to told me that the speaker wire in the stock speakers is some fiber optic wire stuff and they don’t make a aftermarket cdash cd install adapter, therefore if I wanted a aftermarket stereo I must replace all the door speakers and trunk speakers and run all new wires. Well that was obviously out of the question and after much research online I read about a line output converter . Well anyways that is now installed and that is what my amp is hooked up too. So how should I adjust my amp to have good bass but also when I turn the bass down in my car on the CD player equalizer it still turns down. As it is I haven’t been able to find a good adjustment to have both good loud bass but also be able to turn it down on the CD player . Please help .!!!Thanks in advance for the reply.

    • Did anyone actually take the panel off in the trunk and look at the stock amp connections? In that year, it LOOKS like you don’t really have to worry about fiber optic. I just looked up all 5 different schematics for all 5 different factory radio options. The only thing that *might* be fiber optic are options like Bluetooth or Satellite Radio. In 2007 they started using it more often, but typically you only see the fiber optic tied into the amp in models that have the Logic 7 Audio System. And if you have factory navigation, well then yeah, there are no parts for the dash regardless of the amplifier and speaker wiring in those models.

      But if you have the business class CD and you want to change the radio, by all means go for it. Metra makes an installation kit, wire harness, steering wheel control interface and antenna adapter. We’ve even done double dins in these cars using this kit, that’s a bit trickier and requires a true professional, but sounds like the place near you doesn’t know jack about these cars.

      Either way, if you plan to stick with the LOC I would recommend a few things:
      1. Use the LC2i – it has a special circuit to help keep bass levels steady regardless of any internal equalization the stock head unit may be doing as your turn the volume up.

      2. If equipped with the stock subs (underneath the front seats) make sure you get your LOC audio signal from THOSE speakers.

      3. Get a bass knob so you have better control over bass level from song to song and a variety of volume ranges. I just linked to a universal one, but depending on what amp you have, there may be a specific bass knob you can get that plugs right into the amp with a telephone jack style cable.

      I hope that helps! One last thing – again, even if you did have the fiber optic stock amp Logic 7 audio system (no stock nav), it’s all doable and you don’t need new speakers. You could re-use the stock speakers, you’d have to add in external crossovers, bypass the stock amp, relocate the stock head unit to the trunk with a fiber optic extension cable just to keep the car’s warning chimes working. Just an FYI for anyone else researching this same thing, we’ve done it, it works. In the past 5 years I’ve owned a 2008 328i with the professional radio, a 2010 335XI with the Logic 7, a 2008 135i with professional and a 2011 BMW M3 with the Top Hi Fi and Nav and at our shop I think we’ve seen and worked on every different type of audio system BMW offers.

  9. I take it that if I roll the windows down and it distorts at all that means phasing issue. ? I have had a few people tell me to get rid of the w7 and get other subs – that it isn’t what it’s cracked up to be and I’ll get better sq and spl from other similarly priced subs…. Thanks

    • Hey – Quite honestly I have not heard about distortion occurring simply from rolling the windows down. Do you mean like literally you can be sitting and parked and as soon as you roll your windows down it distorts? Or do you mean more like you roll your windows down, crank it up and THEN it distorts? Either way, I would start from scratch and check phasing on everything and re-tune everything. If you hear distortion on every channel individually with the windows down (like you balance to one side and then fade to one channel) then I’d say you might have an electrical wiring issue as well. If you can fade to the front, balance to one side and it sounds fine with the windows down, but then you balance and fade back out to center on all speakers and it distorts – then I’d say yes, it’s being caused by a phasing issue.

      That’s an easy way to check phase. If you fade to the rear and then balance left to right – if it sounds better when balanced to one side than it does balanced in the middle with both speakers playing, then you know you have a phase issue. But when you have 6 speakers and sub you can have phasing issues on multiple speakers so you just gotta go through and check them all. Additionally having both the crossover on, on the head unit AND on the amp can cause phasing issues. So you need a re-tune as well.

      Oh and the W7 is not a bad sub, a bit overkill for my personal preference. I actually prefer the sound and punch of the W6 a lot more. I think the W7 is really more for high output. I think the W6 has a more natural tone and more accurate reproduction.

  10. Hey there! Really awesome you give your time to people like this. Thank you. I have 2 sets jl c5 6.5 and tweeters running off an HD 650/1 watt jl amp and a 12w7 on a HD 750/1 Deck is a Pioneer 4600. 2005 Tacoma Access Cab. I had this set up in the same truck before and it rocked. Sold, and have finally replaced it, and it just doesn’t sound the same. It’s close, but after sound deadening the whole truck myself, and positioning the sub in the same place it was, on the floor passenger side facing driver with the port on top. Still , doesn’t sound right. I have the amp and deck tuned to 60 hz. well 63 on the deck. The main thing I notice is that as soon as i roll the windows down it gets way louder and distorts a lot. when I turn it down so it sounds good with the windows down, and close the windows I can hardly hear it. The problem isn’t the power – it’s the phase. It’s sounds out of phase and horrible. Muddy> ? I don’;t know what to do. The guys at the local shop seem clueless, and I’ve had to figure most of this out myself. Sorry if I am missing any information, and THank you for your time! <3

    • Hey – that sucks, there could be a number of things out of phase. First off, if you can, turn the crossover on the head unit OFF if you’re using the crossovers on the amp. I know on some Pioneer decks you can’t turn the LPF filter off for the subwoofer so if that’s the case turn it all the way up to 125 and then use your crossover on your amp. You will have to check phase on everything. Each mid range, tweeter and the subwoofer. Check out the JL Audio Tools app by Studio Six Digital. There is a way to test speaker polarity. Also set the EQ to flat for now and make sure all things like bass boost, loudness, etc are off. Good luck. Sorry to hear the local shop is so incompetent!

      • Thank you so much for your reply! Def sounds like a phasing issue. I found a position that seems to help a lot which is held firmly by the seat. Is it possible that the sub is strong that without being held down the reference is bad? does that make sense? Like is it moving itself enough that it is messing up its own sound? or is that just a better position? it leaves very little room for the passenger and I think more of my girl than my sub so I am considering cutting out the sheet metal that is the back seat so it can move back more, but I’m also curious if placement is so crucial that a few inches can affect it. If so is it being flat or angled going to change it a lot too? Lastly I notice its way louder when the windows are open at all. I remember this in the old truck but it still sounded good – in this truck it sounds a little off. I know I am a perfectionist and there is only so much I can do – some songs I think I will just have to delete from the playlist, but I wanna do the best I can do. 😉 Thanks again! SO much! <3

  11. Hey Annie, Would you happen to have a list of songs or a CD that you use to do the speaker tests? Something that tests the full range that a sub and speakers can handle?

    • Hey Steve – we usually listen to a variety of dynamic and musical tracks when tuning systems, but I can tell you for like specific frequencies we use an IASCA test discs. Here’s a few tracks off my husbands most recent “Tweaking” playlist:

      Alan Parsons Project – Some Other Time
      Men At Work – Down Under
      Bell Biv DeVoe – Poison
      Sheryl Crow – We Do What We Can
      Lisa Loeb – Do You Sleep?
      Eels – Not Ready Yet
      Steely Dan – Everything Must Go
      Death Cab for Cutie – Summer Skin
      Paul Simon – Kodachome
      Weezer – Heart Songs
      Katie Costello – Stranger
      Goyte – Making Mirrors
      Stephen Swartz – Bullet Train
      Daft Punk – Within
      Bad Suns – Salt

      Nothing screams bass here, this is just a nice sampling of some very musical and dynamic tracks. I hope that helps!

  12. I have a jl audio 750/1 amp with jvc kw 50 bt do I set the sub woofer gain to 0 or 12 with the bass knob on or off and where do I set the frequency filter to of bass the sub is a 2ohms.

    • Hey Jay, normally for subs we set the amplifier crossover to 80 Hz. When adjusting the gain, I would do it with the head unit sub level all the way up and the bass knob level all the way up – then starting bring the gains up on the amp to a satisfactory level. This way you know when you’re maxed out on both you’re still not getting distortion. If your head unit has a high pass filter (HPF) then you could put that on 80 Hz as well assuming you’re using the head unit to power interior speakers.

  13. Hi Anne,

    I recently just upgraded my sub-woofer, From 2 10″ Pioneer Champion Pro Series Subs 800 watts rms 3,000 watt peak each sub in a vented box, to a Sundown Audio 12″ X series 1250 rms 5,000 watt peak sub as follows

    1 Hifonics 2416.1d Mono Block amp (2200 Watts rms True power tested on dyno at 1ohm stable and 1600 watts rms on 2 ohm load)

    1 12″ Sundown Audio X12 4ohm dual voice coil sub-woofer 1250 watts rms wired down to 2 ohms ( sub is able to handle 5k watts on burps) in a 2.65 cubic foot box made of 1.5” mdf wood.

    I have 0 guage wire ran through out my whole car as well as the big 3

    2 XS Power D3400 batteries, 1 under the hood with the Big 3 ran to it and one in the Trunk ran parallel to the 1st one.

    1 8 FARAD capacitor

    touch Screen CD/DVD player

    Only Thing different from my old setup to this current is the Sub and box.

    My question is, I have been adjusting the knobs of my amp the ( Gain, Bass boost, sub EQ, Sub sonic EQ on my amp, I can get it to sound amazing hitting 156 dbls with just 1 12” sub in a dbl test, but while its really loud clean and clear bass. it doesn’t seem to play some of my favorite songs like my old subs did, what I mean is there is certain types of bass my old subs would reproduce that sounded just awesome and I could really rattle my car but when I upgraded to this sub it doesn’t reproduce the bass in the same songs as my old subs did its more of a mellow, settle clean bass, did my old subs make that bass off distorted bass or was it maybe my old subs and box where tuned to a different hrz then my new sub and box? My new sub is about 5 times louder then my old setup bass wise just disappointed when I hear some songs that use to pound and now they don’t

    • I’d go back to the Pioneer’s, but build a sealed box to manufacturer spec, those subs pound! I honestly can’t answer your question too many variables. The only real way to know how they’re different would be to compare both boxes using an RTA and doing a frequency sweep then you can actually see and plot out on a chart at what frequencies/outputs they’re different.

  14. Hey Annie, I recently installed a 700 wattrms hertz monoblock amp with alpine 10″ type R dual voice coil wired in parallel to 2 ohms and I’m getting jack for output unless bass boost on amp is cranked, and and gain is like 75%. I have a shitty old JVC probably only 2 volts, so I get that it needs to be up a bit, but this is ridiculous. Here’s what I think it might be…I’ve got 4 gauge running to my 2 channel up that I’m powering the front stage with, and then spade connectors and 8 gauge running off of that to the monoblock right beside it. Is that a dumb way to power it? Stupid question, I know.

    • Yes, reverse the daisy chain you’ve got going. Your mono needs the heavy duty gauge wire. You’re essentially starving that amp for power with the itty bitty 8 gauge. While you’re at, just get yourself a power distribution block and make it nice. This is the one I would use. Gives you a single 0 or 4 gauge input and two 4 or 8 gauge outputs. Perfect for what you’re trying to do.

  15. hey I have another question do you think that possibly one of the 2 fuses on the amp could have blown an that’s why it’s not as good?

  16. Thanks for the help 🙂

  17. The negative n positive are good made sure cause that’s how I blew my last 2 subs haha, I didn’t disconnect any of the wires goin to the head unit I couldn’t get in it to check I dot have the right tools its a new sub I’ve only had it for four months n my buddy never used it, I’ll try that in the morning, also I noticed that whenever I play dub step or something with mainly bad it will go real loud and steady but when I listen to rap or something at the same volume with not as much constant bass it will cut out. I thought that was weird. If anything it might be something on the head unit they’ve been connected for almost 3 years :/

  18. Hi, I have a m-500 alpine amp and a 10″ MTX sub and I’ve had it for about 3 months and was sounding good and while driving it randomly cut out. The amp was still on and the sub isint blown, I turned my stereo off and back on it worked when the volume was 18 or below out of 35 my booster has always been off and bass always onlvl -8 I thought it might have been the wire connection so checked and re-wired it and it didn’t do anything. I then changed the settings on the amp and I got it to work again with the volume all the way up but it doesn’t hit like I did a couple days ago before this happened. Do you know a suggested setting to put my amp settings on to make it how it was? My settings right now are gain .25v bass EQ +8db and LP filter is at 65.

    • Hi Andrew,
      Do you think by chance when you re-wired it you accidentally reversed the positive/negative on the speaker wire to the amp or sub? Or did you shift the position of box from where it used to be?
      Are you sure the sub isn’t starting to go bad?
      Maybe it’s the pre-out on your head unit that has an issue. For the hell of it, you could try running your RCA’s to the front or rear RCA preout as a test to see if there’s a noticeable increase in output.
      It’s hard for me to know where you had your settings before! The only thing I can really tell you is not to turn your gains up more than 3/4 way.

    • Hi Andrew,
      Do you think by chance when you re-wired it you accidentally reversed the positive/negative on the speaker wire to the amp or sub? Or did you shift the position of box from where it used to be?
      Are you sure the sub isn’t starting to go bad?
      Maybe it’s the pre-out on your head unit that has an issue. For the hell of it, you could try running your RCA’s to the front or rear RCA preout as a test to see if there’s a noticeable increase in output.
      It’s hard for me to know where you had your settings before! The only thing I can really tell you is not to turn your gains up more than 3/4 way and you may want to put your LP filter at 80.

  19. hi annie i have 2 mtx 10″ subs with a 760 watt pioner amp and a kenwood deck and sometimes it will hit hard but will phase out and i have tried making adjustments but nothing seems to work any advice would be appreciated

    • Hi Corey,
      How’s the ground for the amp? Or the head unit? That is a possible explanation for the inconsistent response.

  20. Hi there, i have an e36 with planet audio amp that is 5000 watts, got a kicker that is compatible with the amp but my deck is 300 watts and how do I know tune the amp so that the base is balanced because I barely hear the music, it’s mostly bass. I didn’t want to touch anything because I did not wanna blow my amp or subs. Thanks

    • LOL, that might be pretty tough to balance out your interior speakers with an amp that big running your subs. You absolutely, 100 percent, without a doubt, will have to upgrade your interior speakers to something in the 100 – 150 watt RMS range and get a nice high powered 4 channel (100 – 150 watts x 4 RMS). Then we can start talking about tuning. OR downsize to something in the 500 watt range if you don’t want to upgrade speakers and add a 4 channel. Sorry!

      In the mean time, it would help if your head unit has a built in high pass filter so you could at least try and filter out the bass going to your interior speakers. If you see “HPF” settings in your audio set up on your head unit, turn that on and if selectable, put it around 80 – 100 hertz. That will allow the interior speakers to play a little louder and more efficiently.

      On your sub amp, turn the gain or sensitivity all the way down, turn things like bass boost off, have your crossover setting around 80-100 hertz. Turn the head unit volume up (to where it’s loud, but still clear, no distortion) and then turn the gain up as little as you can to the point where it sounds good to you. If you don’t want too much bass, you want the gain/sensitivity as low as you can get it to where it still sounds good. But with an amp that big, I don’t know if that’s possible. Good luck!


    • Hi Drake,
      Yep, it’s a 4 channel amp alright. That amp is designed to run your interior speakers. It’s a good 4 channel amp, but bear in mind, interior speakers require far less power than subs. So this amp is pushing 60 watts a channel RMS. Use it for your interior speakers and buy a dedicated mono sub amp and you’ll have a pretty nice system.

  21. here all the stuff i thought useful. kenwood 640wyatt maximum power 4/3/2 power amplifier . kac-8401 no.30403215

  22. I have a 650 watt amp kenwood amp. I could get more details if u want. It 4 channel i beleeive id have to go outside and look. With two sony xpload 10’s

    • Yeah, I would really need to know exact model numbers of both amp and sub. Especially if you think it’s a 4 channel. 4 channel amps should not be used for subs, they should be used for 4 interior speakers. That’s probably you’re whole problem.

  23. hey my name drake and i just got a 650 watt kenwood amp. i had a 400 watt dual. that hit hard for some reason lol. so i got the better amp thinking it would hit harder on my 10’s but in face when i hooked up kenwood. it doesent even come close to hitting as hard. im thinking its not tuned right. and im not real smart when it comes to all that lol. what should i do. what are important, i herd bridging helps but my brother says bad for amp. need HELP asap

    • Hi Drake,
      Yeah, there are a lot of things that could be going on here. What amp? What subs?

  24. Heya
    I gots 2 kicker comps in a loaded enclosure with a mrx m50 rated at 586w rms. I was researching overpowering and I was wondering if the rms is a lil overkill and might damage the subs consedering the box is rated at 300 rms.If it is should i downsize or keep this setup with the gains set properly?

    • Hi Vincent,
      I think you’re always better off having more power than too little. My husband John (who’s been installing since 1982, selected Top 100 Installer in US twice) is running a JL 12W6 (600 RMS) with a JL HD1200 (1200 RMS). As long as you’re tuned up properly, gains set accordingly, you should be good.

  25. Hey Annie. Thanks for all this info. I just did my first install in a 2006 Silverado. The head unit I have had for a couple years, Clarion NX500, and just added a Sound Ordnance B-8PT slim powered sub. I am bit confused/overwhelmed with all the adjustments. The head unit has Bass and Treble centers, sub level, sub filter, and Bass Q-factor (?). And the amp has a level, Bass Eq, Phase, and Freq. adjustment. What is the difference between phase and Bass EQ? And how do I dial all this in!?

    • Hi Pete,
      Congrats on the install! In life, and in car stereo, you want to try and keep it simple. Start with things off and eq set to “flat” or “user” on the head unit. So bass and treble levels should be all set to “0”. Sub level is referring to sub level gain, so depending on what kind of music you’re listening to you can easily turn the sub level up or down. Bass and treble center frequency are referring to the frequency that you are adjusting when you turn the bass level up or the sub level up. So if treble center frequency is set to 12.5 khz, and you boost your treble level +2, you are turning up 12.5khz. If you have it set to 10 khz, then that is the frequency you are adjusting when you turn up or down your treble level.

      Sub filter is the built in crossover for your subwoofer. If possible set to off. Not every head unit has this option. If you cannot turn it off, bring it up to 200 hertz. This means the head unit is only allowing frequencies of 200 hertz and down to go to the subwoofer RCA preouts which are presumably connected to your subwoofer amplifier. Then on your amp, you want your crossover around 80 hertz. You do not want them both at 80 hertz as this can cause funky phase issues.

      Q factor is similar to center frequency. It refers to the width of the frequency you are adjusting. So if you selected your bass frequency as 60 hertz and your Q factor as 1.0 that 1.0 refers to how sharply you are dialed into 60 hertz as you adjust the level of it in your bass level adjustment. When in doubt? Leave it in the middle.

      Onto the amp. Level is really a level or sensitivity adjustment. Read the post on tuning a sub amp for more details here. Bass eq or bass boost on the amp usually refers to boosting a certain frequency, usually around 40-50 hertz. Again, start with this off, see how it sounds. If you find you lose a lot of low end bass when you drive, turn it on. The road/tire noise can put your sub bass out of phase which cancels out that frequency.

      Phase can refer to a few things. One of which is having your positive and negative being correct. As in if you have a pair of speakers and one is out of phase, you will have a weird, hollow sound as the sound waves are playing opposite and cancelling each other out (like noise cancelling head phones) and the timing of the reversed sound waves put that frequency out of phase. So if your tires resonate at 40 hertz and your sound wave from your wires are traveling along and meet your stereo’s 40 hertz sound wave from your sub, but they meet when each others peaks and valleys are at opposites, they put each other out of phase, essentially eliminating or reducing that frequency from audible levels.

      Depending on placement of the sub (remember sound waves travel, and bass waves take the longest distances to travel – this is why a vehicle can be such a difficult audio environment), you may be better off reversing the phase of the subwoofer! You can try it both ways and see how it sounds. You should really only do this with subs. You do not want your interior speakers to be out of phase with one another.

      If you still have questions after this and reading the tuning post, please let me know!

  26. ok well i see you prob getin sick of reading my post,so i come to the problem i see that if i switch from a 6 gauge to a 4 gauge al get the complete wattage i need,let alone a new headunit would fix my probelms ty for your time an sorry for all the post’s

    • Hey Will,
      It’s no bother, just busy. I was going to draw up a diagram to show you your wiring options as you can only configure them to either a final load of 2 ohms or a final load of 8 ohms. In the mean time, check out this link, I think it will make a little more sense. Scroll down to the parallel calculator. Right below that is series. Punch in “4” for R1 and R2 and hit “=” to see how it works.


  27. alright well,ive come to think about it i just wana rewire them back to 4ohm but dont know how to do that i dunno if its just the way its wired to the amp he has negative an postive on bother sides wired together then going to there own slot its like the wires runin from one side that are neg n pos are twisted together then put into one side then the same done with the other inorder to put them back to 4ohm would i need to rewire anything inside the box alone or just the way they are wired to the amp itself blah im so confused i really dont wana get charged for a job that could take maybe 5 to 10 min thank you

  28. ok thanks again now last time i had em hooked up in my girls car before mine we had a 4 gauge rockford wire i gave her runin to the battery an the amp witch was a planet auido 1200 watt amp.the subs were wired down to 2ohm. i have negative an postive comin outa both sides of the box i have,so i took thouse wires an twisted them together an then took the wires comin from the planet auido amp an that wore hooked up just negative an postive,and twisted them together an al tell you it was slamin so hard it was makin the computer miles shift or something.all im sayin is i got this american bass amp hooked up to em an it doesnt seem like its doing them justice maybe i should hook that 4 gauge up in my car an take out the 6 gauge an run the plantet audio amp instead once again thank you for your time

  29. sorry for posting so much just speaking my mind as im going with this,is there anyway to wire my 2 12’s down to 1ohm some say id need to run 4 12’s inorder to do this im confused

    • Hi Will, I’m not sure how you had it wired with the last amp, sounds maybe like series, but if that’s the case it would have been quieter in series as the impedance would go to 8 ohms. So there is no way to wire your subs to 1 ohm. You can only parallel which will result in a 2 ohm load or series which would result in an 8 ohm load. If you bought 4 – 4 ohm subs and paralleled them all, you would be down to a 1 ohm load. JL makes great stuff, but if you want good quality and don’t want to spend as much, check out the Alpine Type R’s and a Kenwood KAC-9105D.

  30. i was just thinking before i baught there amp for the subs first i had the subs hooked up to a planet audio 1200watt torque mono amp runin a speaker wire from the negative an postive on the amp then twisted the wire’s runin from both of the negative an postive hooks up on my box i have negative n postive runin from each side of my box then i twisted thouse wires together then twisted them with the amp wires hmmm would think with a actual same brand amp they would work louder n better blah i might sell this stuff an buy new stuff

  31. ty for your reply i will deff update the deck an try to turn off my eq to my android phone,i do use a headphone jack instead of a usb port.gee i really thought i was saving money by going with theese guys i shoulda just baught JL like i planed to with the amount of money i spent for the amp an subs gee

  32. sorry bout the double reply

    • No problem. Okay, so I’m not feeling too good about this company based on their fishy ratings on their products. They only rated their amp’s RMS power at 1 ohm which is stated to be 1250 watts RMS. They don’t tell you what it can do at 2 ohms or 4 ohms. The power will go down as the impedance goes down, but the power that comes out will be cleaner and tighter and the amp will play more efficiently. Based on it having a 100 amp fuse, I think it probably can put out 1250 watts at 1 ohm, but the only way you can efficiently wire your subs is in parallel: tie both positives together and tie both negatives together. This will give you a 2 ohm load. The amp PROBABLY puts out around 500 – 800 watts RMS at that rating. Since your subs are rated at 250 watts RMS a piece that’s an okay power match. If you’re running a true 6 gauge power wire, you should be fine. Some of the cheaper kits out there mix in aluminum (reduces conductivity) and really use an 8 gauge thickness but wrap it in a shield that makes it look like a thicker gauge wire. What ends up happening is you starve the amp for power, it runs inefficiently and you get poor results in output.

      But, I think your weakest link right now is your head unit. It’s not really set up for doing a system, it gives you minimal control over the sound going to your interior speakers and has a rather low voltage preout for your sub amp, only 2.5 volts.

      If you upgraded to something like this from Kenwood, you’ll get so much more control right off the bat just by changing the head unit. The Kenwood has built a high pass filter. What that will let you do is cut out the bass frequencies playing to the interior speakers so you can play everything louder and cleaner and you will be less likely to run into distortion at higher volumes on the interior speakers. On the sub side it has a higher voltage preout, 4 volt. That will increase the sensitivity of your amp and you’ll get more kick out of the amp without adjusting gains. It’s also part of Kenwood’s specialty line and gives you a two year warranty when bought from an authorized retailer like ABT.

      Also, if you’re listening to your music through the auxiliary port to an ipod then you’re compromising your sound quality. Using the headphone jack of an external device also uses the device’s built in amplifier for the headphones as well as the device’s built in EQ which can be adding distortion to your total system sound. If you get something with USB you bypass the amplifier for the headphones (without that you’re kind of amplifying an amplifier as you’ve got the amp built into the headphone jack of the ipod and the amp built into the head unit). Definitely turn off any EQ feature that may be on in your ipod or MP3 player.

      Also, your source of music will make a difference in your sound quality. If you’re getting your music from a file sharing software, the quality is often a copy of a copy of a copy and is usually distorted and compressed and missing frequencies. If you want to use an MP3 player for your music, download your music from itunes or import it to itunes from original CD’s in Apple Lossless.

      Here’s what I’m talking about. An original CD file is like 1411 kilobytes per second. Most MP3’s are compressed to 128 kilobytes per second. That’s a tiny, tiny fraction of the original sound file. So you’ve stripped away a lot of bass and mid range and then you’re using an EQ to try and put it back in and the sound can end up being distorted. So depending on your source of music you may find some songs sound really good and clean and others sound like garbage.

      So to recap:
      Upgrade the head unit
      Make sure you’re using good quality music from clean sources
      Turn off any EQ on your MP3 player
      Use a USB connection whenever possible over a headphone jack
      On your amp have your crossover setting around 80 hertz
      On your head unit, have your high pass filter crossover around 80 hertz
      leave bass boost off on the head unit
      and try to leave bass level flat, just use mid and treble for audio adjustments
      make sure you’re using good quality power and ground

      • Hey how are you? I have a couple of questions about having two different amps one amp rockford fosgate pbr300x4 running 4 interior speakers in high pass option on the amp for the front and rear speakers, this amp comes already from manufacturer at 80hz so I can’t change the hpf to anything else, and reading in one of your earlier posts, you said that don’t ever set crossovers on headunit if they are already set in the amp, because it will cause distortion, second thing I have a jl audio 500 / 1 running a 10 inch alpine type r 10d2 wired in series for a 4 ohm load on a ported box tuned at 35hz, I have the infrasonic at 30 hz with a 12 db roll off, I have my eq on the amp as well and I have the Q at the center position 1.6 and I have the center frequency at 80 hz

      • hello my name is Donavon, didn’t know how to get I contact with you so. I was wondering on my pioneer stereo at the sw menu it has a setting for like 80HTZ 100htz ..I was just wondering what I should have that set to and should it be the same as my lpf on amplifier?

      • Hi Donavon – you want to use one or the other, but if you don’t have the option to turn one off – leave one of them higher than the other. So leave one on 125 or 150 Hz LPF – either at the amp or the head unit – and then set the other one at 80 Hz.

  33. i have a 2001 chevy malibu runin a 6 gauge wire i have a JVC model KD-R210 deck.i have a American Bass PH2500MD 1-Ohm 2500 Watt Mono Mini Amp Amplifier PH-2500MD and my 2 12’s are BASS DX124 12″ 600W 4 OHM CAR ADUIO SUBWOOFER SUB 600 WATT DX-124.Now i been told if i run em at 2ohm like i am i will get them to pound harder but not at there full power but if i leave em at 4ohm they will push there full power

  34. alright here is the details i have i drive a 2001 chevy malibu.i have a 6 gauge wire runing,my head unit im using is a JVC KD-R210 my amp is a American Bass PH2500MD 1-Ohm 2500 Watt Mono Mini Amp Amplifier PH-2500MD my subs are AMERICAN BASS DX124 12″ 600W 4 OHM CAR ADUIO SUBWOOFER SUB 600 WATT DX-124

    •Power Handling:◦ 600W MAX
    ◦ 250W RMS

    • 60 OZ. MAGNET
    • 88.2dB
    Ive been doin some reading i was told that if you run them at 2ohm they will hit harder but wont push full power they can do,but if you run them at 4ohm they will push the full power they can and my amp is a class D mono amp

  35. Hi i have 2 american bass 12’s wired down to 2 Ohms an a 2500 watt american bass amp an it says 1 ohms stable.Certain songs hit hard others dont.i can turn my volume up to 35 an it sounds great inside the car when i open the trunk my speakers sound flaber like.Should i keep my bass on my deck down to -6 i have my mid on +1 an would it be better to rewire my subs back to 4 Ohms or keep them the way they are.Thank you for your time

    • Hi William,
      I’d be happy to answer your question and point you in the right direction, but I need a little more information. American Bass makes 9 different models of 12″ subs all with different ratings and impedance. And they also have 2 different 2500 watt amps.

      Can you do me a HUGE favor and get me model #’s?
      Also what car and what head unit are you using?
      And what gauge power and ground are you using?

      I’ll tell you the best way to wire it and tune it once I have those details. Thanks for posting a comment!

      • I have a 5000 watt Orion and a 5000 watt mono block menace amp with two 6.5 300 watt bass rockers in front doors and two 6×9 voice menace I think there 300 Watts also there on a 1000 watt clarion amp how do I start to adjust this

      • Hi Charles – so normally we would set our mono amp crossover around 80 Hz LPF and our 4 channel (for your 6×9’s and 6.5″) 80 Hz HPF. The idea is the subs play 80 Hz and lower and the mid’s and hi’d play 80 Hz and higher so they each play the frequencies they’re best designed to play. Turn the head unit volume up 3/4 of the way and start with the gains all the way down then slowly bring up just to the point of distortion then back it back down. Hope that helps!

  36. GREAT INFORMATION ABOUT THE FREQUENCIES ~I have a 650 kicker amp mono block with a jl audio w7 10 at how many ohms should I run that? And how do I run them if I have a mono block amp with two jl Audio w3 12 with that same amp witch one will be a better set up and how do I do it with the ohms thanks.

    • Hi Jonathan, I’m glad you enjoyed the article. As for your set up, can you tell me what model Kicker you have? I just want to see the RMS output at various impedance’s so I can properly answer your question. The W7 is a 3 ohm sub. So my concern is your amp may not be enough to power it. The W3’s might be a better set up, but it depends which model W3’s you have. The 12W3V3-2? 12W3V3-4? That will help me determine their impedance (single voice coil 2 ohm or single voice coil 4 ohm) and that will also play a factor in what would be the better set up for the amp you have. Let me know exact model #’s when you get a chance! Thanks. -Annie

      • Hi how’s it going?

        Lately I’ve been having some crazy moments with my car audio

        First when my car wasn’t loud it sounded ok but than I recently got a hole or something in my exhaust

        My question is if the holes right under my cabin would that throw off the way how my systems sounds now ?

      • Hey Joe,
        Absolutely. Tires and exhaust are lower frequencies and can easily conflict with the lower speakers your stereo is trying to play – they can put those frequencies out of phase which essentially cancels them out or diminishes them. Look into some sound deadening like Dynamat!

  37. I have a hifonics mono amp.that is running @450rms.powering a rockford punch12″that could handle 250rms.is it safe?

    • Hi Nigel, it’s all in the tuning. It’s always better to have too much power rather than too little. Just keep the gains a little lower, make sure you don’t hear any distortion or flubbering from the sub, even at high volumes. Thanks for stopping by!

    • I don’t know as much as I would like to know about car audio. But I am positive that as long as you keep your amp at about half on the gain or lower you’ll be OK…. I had one kicker 12 inch comp from wallmart that was running on almost 200 watts more than what you have and I punished it hard for over a year. So yea put ya amp at 80 on the (lpf), gain at half,then equalize your cabin speakers and bump away. Hope I was able ta help.. ( David )

  38. Annie, thanks for the info. It seems I know less than I thought about this stuff. My equipment is as follows:2004 Saturn Vue;Alpine head unit; 2 sets of Kenwood components in the 4 doors, 2 10″ MTX subs, and 2 Alpine amps;m500/f300 ; 2006 Mustang GT; Kenwood DNX7160, stock components/subs in the doors, Pioneer 6x8s in the rear, a Kenwood 8105d amp and a single 10″ MTX in the trunk. thanks again

    • Hi Tim, I’m glad you enjoyed the site and found it helpful. Sounds like you’ve got a nice setup in both your cars. Those Mustangs with the stock premium stock system sound surprisingly good for stock door speakers once you upgrade the head unit and add an amp and sub, right? Let me know if you have any questions regarding your set up. Thanks for stopping by.

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