Subwoofer Troubleshooting(?)

[Magic8Ball]

Hello everyone. I'm looking to get some opinions from you all regarding an ongoing problem I've had with my system:

HU: Eclipse CD5000

Speakers: Focal Polyflex 130h components (5 1/4"), front and rear

Subs: 2 12" Kicker L7's (ported enclosure, facing forward--ported through a ski pass in the rear seat)

Amplifier: Diamond D3 500 x 4 (for Focals)

Amplifier: MTX 81000d Class D (for Kickers)

Lightning Audio 1.0 Fahrad cap.

Deep cycle battery, high output alternator.

Most of these components are 5+ years old but have never failed or blown on me. There has been little sound degradation over the years, as I never turn up the volume past 50%. I've noticed, though, over the past couple of months (since I installed the D3 earlier in the summer) a lack of bass response coming from the subs. I have everything professionally installed, as I know little about installation. My concern is that my installer may have mis-wired or changed some settings on an amplifier to trick me into upgrading my equipment. I recall all of my deck settings being at their lowest levels (non-fade output -6, svc -10, volume 38), and that would be ear shattering (not to mention feeling intense vibration from the excursion).

Now, the sound quality is still exceptional, but bass response is about 1/2-3/4. The subs are still playing, but there isn't as much excursion and that ear-ringing, intense bass vibration feeling is not near what it used to be.

Does anyone have advice for a novice of things I can check on my own without having to take it back to the installer who says everything's fine? Alternatively, could anyone provide insight into what my problem could be if it's not the subs? I thought maybe my frequency settings on my amp could be off, but I think everything hasn't changed. I've tried maxing out the gain, frequencies, and equalizer on the amp (I know, not proper etiquette), but it still doesn't sound the same.

If anyone needs more info., please let me know, and I'll do my best to provide it.

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[ahillworks 10+ year member]

I know silly question but does you radio have a Loud option. If so is it on or off? This option can make a major difference in sound if off or on.

Seems to me a setting within the head unit may have been changed. May want to check your sub options and make sure they seem set right. I will do some more reading on the amps. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif Sorry its not much but its a start right.

 

[ahillworks 10+ year member]

These are the main functions of the amp you have. Incase you did not know I figured I would show you the options and there functions.

1. Gain Controls – These controls are used to match the input sensitivity of the amplifier to the particular

source unit that you are using. The controls are factory set to 1Vrms. :::::This should not have to be all the way up to get what you need keep this in mind::::::

2. Thunder EQ – This equalization circuit is used to enhance the low frequency response of the vehicle’s

interior. With up to 18 dB of boost and centered at 40Hz, the Bass EQ can be adjusted to meet your own

personal taste. :::::::: I Personaly would try to adjust this last :::::

3. Frequency Control – This control is continuously adjustable from 40Hz through 200Hz at 24dB per octave.

Factory setting is at 40Hz. :::::: Based upon what music you listen to I would try to keep this as low as possiable. If not adjust in the 40 to 90 range::::::::

And then your Basics for adjusting the amp.

Adjusting the Gain

1. Turn the gain control on the amplifier all the way down.

2. Turn up the volume control on the source unit to

approximately 3/4 of maximum.

3. Adjust the gain control on the amplifier until audible distortion

occurs.

4. Adjust the gain control down until audible distortion disappears.

5. The amplifier is now calibrated to the output of the

source unit.

If Anyone else wants to add to help this guy cool with me I just wanted to give some basic points is all.

 

[Atimm693 10+ year member]

1. Check the wiring configuration of your subs. What is the resistance of the voice coils? (dual 4 ohm, single 4 etc)

2. I'm assuming that you switched cars. If this is the case, it could just be the fact that the acoustics of the new car are much different than the old and it will not sound the same.

 

[standbackimapro 10+ year member]

You can Set the Gain, the right way with a multi meter, if you turn your Head unit up to your average listening level, You can either leave your subs hooked up or use resistors to create a 4ohm load, but You just have to have the + probe of the multi meter on the + of the speaker terminal and the negative on the negative,

now im not sure what your amps RMS is, but at first have the gain all the way down, then slowly start turning it up, youll see the voltage on the meter start going up, if u know ur rms, set it around there, so lets say your meter is reading 40volts

Thats 400 watts so set it up until its around your desired rms

What your explaining really dosnt sound like a problem, you could just be used to the way it sounds, or it could just be that the gears old. ya know?

use a meter and check the resistance of the subs

 

[ahillworks 10+ year member]

You can Set the Gain, the right way with a multi meter, if you turn your Head unit up to your average listening level, You can either leave your subs hooked up or use resistors to create a 4ohm load, but You just have to have the + probe of the multi meter on the + of the speaker terminal and the negative on the negative,
now im not sure what your amps RMS is, but at first have the gain all the way down, then slowly start turning it up, youll see the voltage on the meter start going up, if u know ur rms, set it around there, so lets say your meter is reading 40volts

Thats 400 watts so set it up until its around your desired rms

What your explaining really dosnt sound like a problem, you could just be used to the way it sounds, or it could just be that the gears old. ya know?

use a meter and check the resistance of the subs

Learn something new every day. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Papermaker85 5,000+ posts]

suspensions breakdown and over time, and its just not as controlled/loud.. also you may have a coil that is starting to open... if you have a DMM check each coil(individually) and measure the OHM/resistance of each... also your gains may have "walked" over time.. sometimes from alot of viberation the gains will lower/raise themselves.. also your alt could be slowly failing...

 

[Papermaker85 5,000+ posts]

You can Set the Gain, the right way with a multi meter, if you turn your Head unit up to your average listening level, You can either leave your subs hooked up or use resistors to create a 4ohm load, but You just have to have the + probe of the multi meter on the + of the speaker terminal and the negative on the negative,
now im not sure what your amps RMS is, but at first have the gain all the way down, then slowly start turning it up, youll see the voltage on the meter start going up, if u know ur rms, set it around there, so lets say your meter is reading 40volts

Thats 400 watts so set it up until its around your desired rms

What your explaining really dosnt sound like a problem, you could just be used to the way it sounds, or it could just be that the gears old. ya know?

use a meter and check the resistance of the subs

wattagepower) is volatge(pressure)X amperage(current)... he needs to know resistance to know output... Im sure you know this...althought you can do it this way... you have to make sure you defeat any other options like filters,bassboost etc.. the best way i find to do it is use -3db tones i good DMM and ammeter so you can know your real output figures... other wise your just guessing... the next best thing is to set it to a certian voltage and listen.. slowly raise the gains in turn increasing output voltage and listing do this untill you have audible disortion... also note not many DMMs are accurate below 40hz and above 70hz... not tring to correct you i know your simplifily things but i think he needs to be informed that way he doesn't confuse others...

 

[Magic8Ball]

Thanks for all the input everyone.

Loudness is turned off in the Advanced Mode of my deck.

And yes, most of these components have been in a previous vehicle, however, it's the same make and model ('94 LHS--->'01 LHS). Both were very loud up until recently and had similar setups.

Unfortunately, I don't have access to a lot of testing equipment and accessing the subs (which I believe are 4 Volt DVC--they're the first L7s to come out) is difficult. It's difficult for me to remove the box, as it's bolted (done by the installer).

I was able to access the amps and noticed that the installer did set the frequency, gain, and Thunder EQ to maximum, which I assume is how it was since installing it as I never touched the settings. I can only assume then that moderate volume over the span of nearly six years is simply wearing components down.

I can only assume the cause of the problem is the subs or the sub amp, as in order to compensate for loss of bass response, I've had to change settings on my deck (e.g., Non-Fade from -6 to 0, Source Volume Control from -10 to 0).

I suppose I will take it back to the installer and recommend they run some of the tests you all have mentioned (as they're better equipped than I and hopefully kind enough to give me a straightforward answer). Not looking to spend thousands of dollars again //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Magic8Ball]

Well an update after a couple of months.

I decided to buy new DVC (4 ohm) Kicker L7s last week to replace my old ones thinking this would solve the problem. After a couple of days of listening to them, I don't really notice a huge difference in bass response (keeping all my deck settings at minimum as before). As I stated in my original post, my old L7s pounded at minimal settings on the deck--the gain, frequency control, and ThunderEQ were pretty close to being maxed out. These were set by the installer and not myself. With keeping the deck settings constant and getting new subs, my next logical conclusion would be my amp, however, I wanted to explore any other possibilities. If it's the amp, they would recommend the ZX 1500.1 for juice. Could there be something wrong with my HU? Wiring? Again, not having a lot of testing equipment around forces me to go back to my installer. This has become an obsession, and I am looking for a definite answer. What kind of things can I ask my installer to do before committing on a sale?

I also am experiencing lights dimming at half volume. I recently replaced my alternator to 120 volt and still have the 1 Farad cap in the trunk. This installer swears by caps, however after reading through the forums, many have installed batteries in the back. I don't park my car and play music. Should I invest in a second battery for the back or should I replace the capacitor?

Thanks again everyone for the input.

 

[Magic8Ball]

Bump*