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Look at your headunits RCA outputs. If you have sub outputs, then use those. If you dont, then you are using either rear or front RCA outputs (depending on how many pairs you have). In using those, when you change the balance, fade, bass, and treble, it will affect the amps output. Those RCA outputs are actually designed for an amp that will be used for speakers, not a subwoofer BUT you can still use it for subs though if you change the headunits settings like I mentioned above, it will affect the way the sub sounds. In my fiance's car, she has a Aiwa headunit. It has a single pair of RCA's which are ran back to her amp (which powers her sub). On her settings, I have her bass at 0, her treble doesnt matter cuz it wont affect the sub, and the fade and balance at 0. This setting works for her. If I was to change the fade from back to front, I would lose the rear speakers PLUS the sub. Thats just how they have the RCA outputs wired in comparison to the speaker outputs. understand this?

Another thing, what kind of enclosure is your subs in?

yea my stereo has rca front and rear.
i have the cable hooked up the the rear ones.

i have a 2 speaker box, sealled

Is each sub isolated from eachother? Meaning is there a divider that makes each sub have its own chamber?

yea there is a divider between both.

Well the woofers could be out of phase.

What exactly do you mean that it doesnt really work when the balance is to the middle? You only have output when it is balanced to the left OR the right?

I like the use of 'sub' as a verb ...

ok well on my stereo where it has the option to choose the balance if i offset the sound to the right a little bit it sounds good. then if i choose to balance it to the right just a bit it sounds good. the problem is that when i leave it perfectly balanced it sounds distorted.

As Coppellstereo stated earlier, you have one of your woofers wired out of phase. On one of your woofers, only one of them, switch the positive and negative wires. Remove both wires and put the negative wire where the positive wire was and put the positive wire where the negative was.

ill try that right now and then ill tell you the results

I have a dual bandpass box with fiberglass in the front middle and subs firing towards eachother but facing on an angle towards the front. Is it true I need to have 1 of the subs out of phase (positive and negitive switched) in order for them to sound right? I ask this because I ripped the subs out of the box and then later on put them back in but forgot how they were set up.

Audioman, from the info you gave and the box I am imagining you have, no I do not think this box needs to have one woofer inverted. But if you put it back in the vehicle and it is not doing what you remember it was capable of, reverse one of the wires and see. It will not hurt a thing to try it. It will be quickly obvious which is the correct way.

I guess Rodolfo got it fixed. He hasn't let us know what happened. I am betting he is riding and not even thinking about us.

Well lets see.... My subs face eachother in a sealed chamber. The backside of the subs are vented each with 2 port tubes. When I have them both phased in (wired positive and negatives the same for both) I hear quick, thudded bass something like muffled bass where its like each sub is pounding against eachother hurting the others bass. Would this mean I need to phase 1 sub out? Also, when I phase 1 sub out, does it matter which one I phase out? I ask this because if 1 of my subs was phased out, I dont know which one was. All I know is that I pulled the box out, pulled out both subs and put them in ported boxes. I didnt like the results so I went and put them back in the bandpass. Also, I had all my settings changed on the amp and dont remember where I had them set. I thought I had the amps gain at 1/2 and the bass boost at 1/2 which is 12DB. But now, I have the amp's gain more than 1/2 and the bass boost at about 18DB and for some reason I dont feel its as loud as it was before. Could this be because I have the right sub phased out and the left sub could have been the one phased out before? In other words, is it possible to have more bass if I was to switch which sub is out of phase, or doesnt it matter?

If this box is the only subs in the car, it does not matter which one is out of phase. Now with more info on your enclosure, I am sure that you do not wire those woofers out of phase.

Here is a picture of what the box looks like. I have the one on the right out of phase. In a box like this, would I need one out of phase?

posted_image

That is just the box I was imagining you had. No you do not need to put a woofer out of phase in that box.

Ok so they should both be wired in phase. Ill change that tomorrow. Ill listen to it after I change it, but what if they dont sound right afterwards? I mean I have the one out of phase right now and the bass hits good, but not as loud as it was prior to me ripping the box out. Could they not be as loud now because the 1 is out of phase? Also, if I was to have them both in phase and they dont sound right at all, would this ruin my subs if I only have it set that way for a minute?

No it will not damage your sub. Just switch it tomorrow and let us know what happens.

Ok 1 more thing before I stop for the night. When I have 1 sub wired up and listen to it it will have its "bass". When I wire up the other one as well, the bass should increase because its now 2 instead of 1 correct? Another thing. If I was to have only the phased out sub wired up, would the bass in that sub be just as loud as if that sub was wired in phase? Understand what I mean?

Yes when the second sub is connected the bass should increase. If this is the only subs in the vehicle, it will make no difference in sound pressure, whether the sub is electrically in phase or out of phase. The above statement only holds true with one of the two subs connected.

I didnt get to work on the car yet today because we had snow this morning and I need to wait for my car to dry off. Anyways, I was looking at another port (dont recall which) about phasing. They talked about moving the enclosure around and something about having the ports close to the back of the trunk. I dont know how that would make a difference. Right now I have the bandpass box facing the back of the trunk about 6" from the back. If I was to move the back closer, say to 3" away, would that improve my bass (loudness)? Doing it that way, the bass wouldnt travel as far when it hits off the back of the trunk. Does this mean anything?

audioman2007 wrote:

Ok 1 more thing before I stop for the night. When I have 1 sub wired up and listen to it it will have its "bass". When I wire up the other one as well, the bass should increase because its now 2 instead of 1 correct? Another thing. If I was to have only the phased out sub wired up, would the bass in that sub be just as loud as if that sub was wired in phase? Understand what I mean?

yea that is the same problem im having.
and no i havent fixed it.
i live in chicago and its kinda snowing so i havent really had a chance to fix it.

Ok so what exactly are your problems? Maybe we can help eachother out.

Ok I finally went out and worked on my system and heres the verdict. First off I had the box too close to the back of the trunk. I remembered that when I measured from the back of the box to the back of my trunk, I had 21" but when i measured it now I only had 19". So I went and pushed everything front. Then I went and changed the right sub so it was in phase but they sounded bad that way. When only 1 sub was powered it sounded good, but as soon as I powered the other in phase sub, the bass went down. Then I switched the right sub out of phase and tried again. The bass went up alittle when I wired it back up. Then I went and turned my gain back down to half and my bass boost to half also. After it was all said and done, I had the bass boost too low and the gain too high along with the low pass filter alittle too high. So I turned the low pass filter down alittle. I now have the gain at 1/2 maybe alittle more, and have the bass boost at 3/4. It sounds very good now.

lol bass boost should not even be needed..with your gains set at half and bass boost at 3/4 have fun with a clipped signal.

no clipped signal whats so ever. I can have the bass boost all the way up and no clipping. I can have the amp maxed out and no clipping either. Oh and another thing, my last amp I had maxed out. The amp was 5 years old before I sold it to upgrade. My subs are now 7 years old and arent stressed at all.

audioman2007 wrote:

no clipped signal whats so ever. I can have the bass boost all the way up and no clipping. I can have the amp maxed out and no clipping either. .

How do you know? Have you scoped the amp at full output?

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I can easily tell that my amp is not clipping. 1. My amp never gets hot. 2. I have the amp wired to 4 ohms. 3. I have the output on my headunit turned to negative 2 DBs. 4. I have very clean and tight bass. 5. I only get bass notes when I need bass notes. I never have bass notes blend into eachother. 6. I never have the bass cut in and out. Thats how I know my amp is not clipping.

But I am doing this ALL by ear. I might very well have a clipping signal but cant hear it. What else could I do to check if I do indeed have a clipped signal?

audioman2007 wrote:

I can easily tell that my amp is not clipping. 1. My amp never gets hot. 2. I have the amp wired to 4 ohms. 3. I have the output on my headunit turned to negative 2 DBs. 4. I have very clean and tight bass. 5. I only get bass notes when I need bass notes. I never have bass notes blend into eachother. 6. I never have the bass cut in and out. Thats how I know my amp is not clipping.

Then you are probably 100% wrong. None of those things will tell you that your amp is clipping. Indeed, I would bet money it is.

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Then explane to me what I can do to see if it is. Ill go out right away and do what you said. I dont have any fancy devices to use though, so what else could i try?

Also, if you are running an amp at a constant clip, then what would break, the amp or subs? And how long would it take till it breaks?

I also just read one of the old closed topics about clipping. A clipped signal will heat up the subs voice coil. Ok, well how long would it take till the voice coil heats up? Also, is this something I could tell by simply touching the sub itself? I am asking this because I have had these subs for over 6 years now. I obviously ran them into clipping with my old amp and am obviously doing it now with this new amp which I have had for over a year. What I dont understand is that if I am clipping the amps and subs, then how comes my old amp lasted 5 years plus, and my subs are over 7 years old? I am in no means second guessing anyone on here. You all just have me worried and I want to make sure everything is alright with my system.

Clipping by itself will not "break" anything. A clipped signal can sound really flat and dull, and it can allow an amplifier to pass higher voltages than its rated power and potentially burn out a speaker voice coil. If you don't have an oscilloscope (the only meter that can show you that your signal is clipped) there is a test you can do by ear to listen to what a clipped signal sounds like. Do you know how to set your input gain using a test tone? The point where the tone changes is the onset of clipping. If you use this method to set your gain properly, and leave the bass boost off, then you can be sure your amp is not clipping. Have you done this?

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Well the fact that I understand nothing of what you just said means that no I havent tried it before. If you can tell me what all I need supply wise and what I need to do step wise, I will do that today. Thank you.

audioman2007 wrote:

Well the fact that I understand nothing of what you just said means that no I havent tried it before. If you can tell me what all I need supply wise and what I need to do step wise, I will do that today. Thank you.

That's what I was afraid of. This is very basic installer-101 type stuff and should be well understood by anyone on this forum before they try to give advice to others.

The procedure has been explained here many times and will undoubtedly come up with a simple search for "setting gain" using the forum search function. But here's the basic procedure:

1) Record or obtain a CD with a test tone of about 60Hz (0db)
2) Disconnect your mains speakers. Set your subwoofer amplifier input gain at its lowest point. Set HU subwoofer output to max. Set all tone controls, loudness, bass boost, etc. to flat or off.
3) Play your test tone on repeat. Slowly turn up the HU volume until you can hear the tone change. Back if off slightly until the tone returns to its original 60Hz. This is the point at which your HU introduces a clipped signal. Note this volume and NEVER GO HIGHER THAN THIS when using your system. Some good quality heads will not clip. If you get the volume to max and cannot hear the tone change, set the volume to about 75% of max.
4) Wear hearing protection.
5) Go the the subwoofer amp and very slowly turn up the gain on the amp until you hear the tone change again. This is the point where the amp introduces clipping. Back it off until the tone is again 60Hz and leave it there. This is the gain setting that matches the max clean output from your HU.
6) Turn the HU volume down and stop the CD Reconnect the mains speakers and play some music. If the sub is too loud in relation to your mains, you may turn the gain DOWN a little to create the blend you need. NEVER turn it up past the clipping point.

The same procedure can be used to set the gain on your mains amps, only using a test tone in the mains range, say around 1500Hz..

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"This is very basic installer-101 type stuff and should be well understood by anyone on this forum before they try to give advice to others". Certain members here have a history of such inexperienced and borrowed advice.

Hey now. I take great offense to those comments. First off if I recall all advice on here recieved is recieved at your own risk. I give advice to the best of my knowledge, and am not saying at any point that I know EVERYTHING about this stuff. Even the smartest on here dont know everything either. I greatly appreciate you all helping me with this but I dont need those comments either. I learned something, and maybe there is something on here that you might need help with. I thought I knew about clipping but obviously I was wrong.

Anyways, I remember that my bass boost on my amp is for 60Hz and goes from 0 to 24DBs. Right now I have the gain at 1/2. I have the bass boost to about 14DBs. If I was to have my sub output to MAX, it would be at +6db's. Right now I have it at -2Dbs. Out of 40 volume I have it at 30 and dont go above that. I just have 1 more question. You said to get a test tone of 60Hz. Now with my bass boost being at 60Hz, does this mean that only 60Hz and around that will be clipped? If I was to back down the bass boost to 0, would the clip simply go away? What I am saying is that would I only have the clip signal during the bass boost frequencies which in this case would be 60?

Just stop, set your sights on getting the gain set as DYohn explained, and then go from there. Here are two sources for test tones that you can make yourself using your computer:

https://www.realmofexcursion.com/main.html

https://www.nch.com.au/tonegen/

Otherwise you are continuing on a line of questioning that is going around in circles. IIRC, I told you a couple months ago that when you refer to the gain dial "position" that you need to learn how to set gain properly. Criticisms such as offended you are appropriate for this forum, and indeed are offered without prejudice. Everyone here has been criticised and have summarily been offended, but we all get over it and learn from it. I've certainly had my share and know I'm not immune to it, but I nevertheless know that more often than not I learn from it.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Turn off the bass boost...it is not needed if everything is set up correctly

a bandpass box masked distortion very well so its harder to hear it.

Turn off the bass boost and set your gain with the test tone. 14DB boost. I'm not exactly sure but I think its something like this

3db = twice the power
6db = four times the power
9db = 8 times the power
12db = 16 times the power.

So at 60Hz the amp is trying to put out over 16 times the power it can push???

Not really sure though...correct me if I'm wrong

Yes anzboi3644 that is basically correct, and is why bass boost should never be used in a properly setup system. It's only purpose is to mask problems in inadequate systems.

audioman2007 I'm sorry if I offended you but let me correct you about something. This forum is to teach people about installing car electronics and how to use them correctly, not for sharing "the best of your ability." If the "best of your ability" is wrong or incomplete, I will be here to correct you whenever I notice it - you or anyone else, I am not picking on you. And I expect the other pros on here to correct me too when I screw up. Bottom line: if you do not understand how to set your gain - and many of your posts illustrate that you apparently do not know how to do this - then you should not be offering advice on system setup to anyone else until you correct your ignorance. The instructions I posted may help you do that. Forget everything you think you know and learn to do things correctly, and you'll be a much more valuable asset to this forum. Thanks!

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When I have my gain set to 1/2 and my bass boost at 0, then my bass production sucks. I use the bass boost to get that hard punchy bass. When I have it at 0, all the bass sounds the same and isnt loud.

If your bass sounds weak when the gain is properly set than the problem lies with the enclosure and sub setup

What is the difference between a bass boost rated at 12DBs at 60Hz and a EQ that has a band of 12DBs at 60Hz?

audioman2007 wrote:

What is the difference between a bass boost rated at 12DBs at 60Hz and a EQ that has a band of 12DBs at 60Hz?

Nothing. Both add artificial electronic signal strength within a specific frequency band, and both can be equally damaging to a system.

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Ok well First let me apoligize to everyone in here for my ignorance. I went and did what you all said "finally" and had very great results, BUT I had to do things alittle different. Here is what I did. I went and took a 15 second test tone at 60Hz like you all said and went and made 20 tracks of it in Itunes having the track break at 0 seconds. I went out and disconnected my rear speakers (sitting on my back seat) so that I can pull down my seat. I then adjusted the crossover which was too high. My headunits subwoofer crossover is set too 120Hz and I have the amps set alittle lower, maybe 90. I then turned the bass boost down to 0 and also turned the gain down. I then turned the headunits sub output setting from -2Db to 0. I took out my music cd and placed in the test tone cd. I left it play at a volume of 30 (which is what I listen to my music at) and then slowly turned the gain up. I was able to get the gain to about 3/4 before the bass changed from being clean to distorted and off tone. I then backed it down, but then had to back it down to 1/2. I had to back it down to 1/2 so that I could turn the headunits output up to its max of 6Dbs. I cant have it at that setting then turn the gain up because I have neighbors that will call the cops. So I dont actually know how it is. Actually I didnt turn the headunit up untill I was actually driving. Before then, the bass was alittle on the soft side, then after I turned it up to 6Dbs, it sounded just like it did before when I had the bass boost up. The bass now sounds very crisp and clean, (just like it did before). The hard punches are alot smoother. When I played some of my rock/heavy metal, the higher bass notes (you know the kind of bass when you listen to rock) was alot more punchier, something I wasnt used to. Is that a good thing or bad thing? Give me some ideas of the differences I should be having now compared to back when I had the bass boost.

so heres the word on my problem.
check my wiring on one of the subs and it turned out to be that one of my subs was wired wrong.
so i rewired it and now it is all good.

How exactly did you have it wired?

He had one of them wired out of phase.

you only want 1 out of phase is the subs are facing eachother (canceling eachother out when they hit) correct?

audioman2007 wrote:

you only want 1 out of phase is the subs are facing eachother (canceling eachother out when they hit) correct?

No, actually you want your speakers to be acoustically in phase at all times. This means in some cases the electrical phase of some may be different, but the key is that the entire system is in phase acoustically.

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Some very interesting reading about acoustic and electrical phasing written by Richard Clark.

autosound2000 offers some great testing tools and some cool gadgets, I had forget about them.

www.monstercable.com/mpc/stable/tech/A2500_Speaker_Phase.pdf

audioman2007 wrote:

Here is a picture of what the box looks like. I have the one on the right out of phase. In a box like this, would I need one out of phase?

No, this box does not require that one woofer be wired out of phase with the other. If you had a one chamber enclosure with one woofer mounted in the traditional fashion, and a second woofer mounted with the cones of the woofers facing each other (magnet and basket outside of the box). You would have to wire those woofers out of phase.

sub problems