Subwoofer Not Sounding Like It Use To

[keep_hope_alive Premium Member]

the gain is input sensitivity to match the HU output. the HU has up to 4V outputs. you have your gain too high right now. you've jacked up your sub level and bass boost to get more output.

all this means your sub amp is just too small and your pushing the amp to it's limits - maybe beyond. i can assure you that it's clipping sometimes. it's possible the amp is having issues. winter can be hard on amplifiers, especially inexpensive ones like that MTX. i've seen amplifiers fail just from extreme cold.

 

[malibuboats91 10+ year member]

On both amps its too high? How do I know what to put it down too?

 

[BrownVanMan 10+ year member]

if the speakers in your car are yo your liking then get a test tone and use a digital multi meter and get the gain set correctly, you wany 500rms at 4 ohm right? so you take 500*4=2000 the square root of 2000 is 44.7213595 get that to show up on the multi meter on your test tone

 

[keep_hope_alive Premium Member]

the above post is explained in more detail here:

http://forum.sounddomain.com/ubbthreads.php?ubb=showflat&Number=65167&page=1#Post65167

 

[malibuboats91 10+ year member]

I watched the video but would just like to clarify some things before I do it so I don't mess up anything. So I basically download the 50Hz and 1000Hz test tones and play them through my speakers and adjust the gain till the meter says the correct number with my deck turned all the way up from what I understand. Now do I keep the subsonic and LP filter adjustments as is? Then I would put the subwoofer level adjustment to 15 and the bass level to 7? As i stated before, with my sub does it matter for this gain adjustment that the positive on the amp goes to the negative on the sub and the negative on the amp goes to the positive on the sub?

 

[subzero 5,000+ posts]

when you say that you have been messing around with changing the sound. I assume that you have been playing with the gain settings too. When I look at your setup I immediatly thing that your wires are to thin. You might need to slap 4 gauge on each amp and 0 gauge from battery to the fuse block and distroblock. Next you need to make sure you dont have that four channel clipping any drivers. You could turn the gain up and cut the high pass freq up, but then your pulling current away from the sub amp. I went through this with my system a few times till I got the settings down and increased the amperage draw capabilities by going with o gauge wire. Try this and keep in mind that the gain settings are to match the output of the deck. turning the gain up more will only lead to clipping at higher volumes which will seem to come alot fast when you shorten that spectrum. clip would start around 30? lets say you got a volume spectrum of 50. ok well turn it all the way up and turn the amps gains all the way down . then slowly turn up the amp gain till it starts to sound distorted then back of a bit till it has gone away. Then do the same for the sub...

 

[keep_hope_alive Premium Member]

I watched the video but would just like to clarify some things before I do it so I don't mess up anything. So I basically download the 50Hz and 1000Hz test tones and play them through my speakers and adjust the gain till the meter says the correct number with my deck turned all the way up from what I understand. Now do I keep the subsonic and LP filter adjustments as is? Then I would put the subwoofer level adjustment to 15 and the bass level to 7? As i stated before, with my sub does it matter for this gain adjustment that the positive on the amp goes to the negative on the sub and the negative on the amp goes to the positive on the sub?

NEVER max out your bass level on the head unit. I don't recommend you go any higher than +3. You introduce too much distortion with maxed out settings.

Head unit volume should be at 30, not 35. Sub level at 15.

it doesn't matter the polarity of a single sub. that is all the wiring change does - reverse the polarity. the sub doesn't care which way it is, it works just the same. It's possible the wiring is reversed in the box and they just switched it on the outside for ease.

use the 50Hz tone for the sub and 1000Hz for the speakers.

There is a good argument for disconnecting your speakers and using a non-reactive load bank. but you don't have a load bank. since your amps aren't regulated, you can do this test with the speakers disconnected. not only will it save your ears, it'll save your speakers as well.

I think 4awg power and ground wiring would be sufficient to your distribution block, then 8awg from there. Your amps aren't big enough to warrant 1/0.

Use a DMM, then use your ears to listen for distortion.

 

[malibuboats91 10+ year member]

when you say that you have been messing around with changing the sound. I assume that you have been playing with the gain settings too. When I look at your setup I immediatly thing that your wires are to thin. You might need to slap 4 gauge on each amp and 0 gauge from battery to the fuse block and distroblock. Next you need to make sure you dont have that four channel clipping any drivers. You could turn the gain up and cut the high pass freq up, but then your pulling current away from the sub amp. I went through this with my system a few times till I got the settings down and increased the amperage draw capabilities by going with o gauge wire. Try this and keep in mind that the gain settings are to match the output of the deck. turning the gain up more will only lead to clipping at higher volumes which will seem to come alot fast when you shorten that spectrum. clip would start around 30? lets say you got a volume spectrum of 50. ok well turn it all the way up and turn the amps gains all the way down . then slowly turn up the amp gain till it starts to sound distorted then back of a bit till it has gone away. Then do the same for the sub...

I havent been playing with gain just the settings on the deck. What do you mean by clipping?

 

[malibuboats91 10+ year member]

NEVER max out your bass level on the head unit. I don't recommend you go any higher than +3. You introduce too much distortion with maxed out settings.
Head unit volume should be at 30, not 35. Sub level at 15.

it doesn't matter the polarity of a single sub. that is all the wiring change does - reverse the polarity. the sub doesn't care which way it is, it works just the same. It's possible the wiring is reversed in the box and they just switched it on the outside for ease.

use the 50Hz tone for the sub and 1000Hz for the speakers.

There is a good argument for disconnecting your speakers and using a non-reactive load bank. but you don't have a load bank. since your amps aren't regulated, you can do this test with the speakers disconnected. not only will it save your ears, it'll save your speakers as well.

I think 4awg power and ground wiring would be sufficient to your distribution block, then 8awg from there. Your amps aren't big enough to warrant 1/0.

Use a DMM, then use your ears to listen for distortion.

So I can do the adjustment with out the speaker connected? So on the head unit put the bass to +3 for setting the gain?

 

[malibuboats91 10+ year member]

Okay so I adjusted it and the gain on the amp is set on 1 which is half way. The sub is alot quieter than it was. Does this sound correct or did I do something wrong?

 

[keep_hope_alive Premium Member]

don't turn the gain up (lower number). if it's not loud enough, the amp is probably too small. IMO - your gain is dangerously high already.

to set it correctly you need to use a DMM or an oscilloscope to measure the output power and set it with 0dB tones so you don't exceed the amps power rating (and clip)

 

[malibuboats91 10+ year member]

I am using a DMM. I put the Bass to +3 and the sub level to 15. I disconnected the speaker and turned my alpine deck up to 30 out of 35. I turned the gain up till 44.72 was displated on the screen and my gain is half way up. It used to be between 2/3 and 3/4 of the way up. I car barely hear the sub where it used to pound good w/o any distortion.

 

[malibuboats91 10+ year member]

Okay so after I responded to the last post I began to think...maybe my system sounds like shit because my 4 channel amp isn't "correctly" set yet. I did the equation to calculate what the DMM should say. My speaker which is an infinity kappa 60.9cs is operating at 2 ohms and the rating of my Eclipse ea3422 amp is 70 watts rms this would make the setting I need to be 11.83 (correct me if I'm wrong). So I went out to my car and did the same thing I did before for my sub. After doing this and connecting all the wires, I turned my system back on and it sounded alot better! The way I take it is basically instead of only turning the dial up on my deck half way to get really loud music, now you have to turn it up closer to 3/4 of the way and have balance bass with treble.

If I did this correctly, my only other question is...what do you recommend me to set the bass center frequency, treble center frequency, HPF and LPF to on my deck?

 

[keep_hope_alive Premium Member]

glad you're starting to get this sorted out.

use the eq to your tastes. setting an eq - center position, Q, boost, etc. is something that can only be done while listening to the system, or maybe viewing an RTA graph taken at several locations.

set the eq how you like it, but try to keep any boost below +4.