Subwoofer advice

I'm guessing probably the amp, but if you burned the coils, then definitely the speaker.

It's not getting quieter or hitting softer, you're just going deafer, lol!

When looking at wattage for speakers you do not want to buy amps based off the max output. You want to look for the RMS or nominal watts.

As for your problem I am not quite sure

traugdor said:

Hi, all!

I'm relatively new to these forums, long-time lurker, first time poster.

Got a question about my subwoofer in my car. I have a Kicker Comp-VR 2 ohm DVC (2 ohms per coil). The speaker is rated at 800W max and it is paired to a JCPower M800D amplifier.

My question is: Why would it gradually become quieter over time and if I would need to replace the speaker or the amp?

Additional info: I have possibly burned one or both the voice coils in the speaker, because I have smelled something like hot electronics (hot wire/glue/enamel insulation burning). Would this contribute to the quieter sound? I'm having a baby soon, and the car it is in will be the baby-mobile, so I don't NEED it as loud as it was, but I am concerned because I have the gain on the amp all the way up and it just doesn't hit like it used to. I just want to be sure I'm not damaging it further and will basically have an expensive box in the back of my car...

Click to expand...

Test: use a digital multimeter in parallel across the speaker terminals on the amp. Set it to AC voltage and a setting higher than 20. Play music at normal listening volume. As it becomes quieter, see if the voltage is dropping on the meter. If it is: amp or battery. If not: speaker or deafness. If you're listening to music at a very high volume, 1) you're causing irreparable damage to your hearing and, 2) after a period of time at a certain dB level, your ears will go into "protect mode" to protect themselves from the massive dB levels. During this time, sound will appear to you to become quieter. It is usually followed by a high pitch tinitis once the offending high volume ceases.

pbf98 said:

When looking at wattage for speakers you do not want to buy amps based off the max output. You want to look for the RMS or nominal watts.

As for your problem I am not quite sure

Click to expand...

THIS^^^^

Often times people get confused. Max doesn't really mean anything. Look for RMS. Also as a rule of thumb it is usually ok to over power the RMS of a sub just a little bit. You'll actually get more distorted sound if you under power it than over powering it. So if a sub has an RMS of 250 I would put at least 300 RMS on it.

Sorry to bring back an old thread, but having been in the pro audio circuit for a little while I feel the need to add in on this. Regarding the multimeter test, that is all correct. Having turned your gain to max, you probably burned out the amp, if not both. The gain actually needs to match the output from your head unit. Having gain so high will make the amp circuits overload and the subwoofer bottom out causing that to burn out.
Best possible output is with an oscilloscope hooked to the RCA outputs, turn volume all the way up until you see clipping (top/bottom of the wave goes flat), then bring it back down to a smooth curve. After that, hook the oscilloscope to the speaker outputs from the amp and do the same thing. At that point, you've got maximum volume possible.

With matching subwoofers with amps, check both RMS and max outputs for both. Sometimes you can match RMS loads but have the max output of the amp higher than the subwoofer, which you don't want. Having the max higher on the sub compared to the amp means nothing goes up in smoke.

Other ways to deliver more power as needed would be a capacitor if you're not too high in power needs. Also, replace battery cables, alternator cables, and engine ground cables with thicker oxygen-free copper cables. Last one is to upgrade to higher output alternator and battery. Follow all that and you're going to have a good kickin system.

ZeroGeined said:

Sorry to bring back an old thread, but having been in the pro audio circuit for a little while I feel the need to add in on this.

Other ways to deliver more power as needed would be a capacitor if you're not too high in power needs.

Click to expand...

How long have you been in this imaginary circuit? A week? Never use a cap, ever... They cause much more of a strain on your electrical system than your amp could hope to do.

Slobalt7 said:

How long have you been in this imaginary circuit? A week? Never use a cap, ever... They cause much more of a strain on your electrical system than your amp could hope to do.

Click to expand...

Actually, if you had properly read my post, I said if you're not too high in power needs to use a cap. If you're doing a high power system, then add batteries seeing as how a capacitor doesn't supply enough power. A capacitor will not cause damage to your electrical system unless you have no clue what you're doing.

A cap stores very lil power, and after that power is gone, your electrical system is trying to restore that power as well as supplying power to the amp, so its harder on the electrical system, as a battery holds alot of power, and wont drain in seconds like a cap, so it can supply proper power to the amp, while the alt charges the battery, which results in less stress on the amp and alternator! So once again, Never use a cap.

Here is a more detailed explanation if you feel like a good read: Car Audio CAPACITORS: Why They DON'T Work

Those are flea market amps

Regardless, when you say "...gradually become quieter over time...?" do you mean while you are driving through the day/night, or does it appear to become quieter from one day to the next?

Reason I ask is because if you a drawing a lot of current, your car's stock charging system may eventually lag. Some cars have somewhat beefy alternators, while others don't. My Chrysler has a 160amp alt while my previous Honda was less than 80amps.

You may already know this...?

You also may be going def (no joke).

*edit* you have the gain all the way up... there is your problem.

dibblebill said:

I'm guessing probably the amp, but if you burned the coils, then definitely the speaker.

Click to expand...

Yeh, if the OP is "smelling wire/glue/enamel insulation burning" which does sound very much like a speaker voice-coil burning up, that's definitely over-driving things. And would account for the sound becoming quieter over time. If the speakers coils are becoming overheated, electrical resistance increases with temperature, and increased electrical resistance means less power, and so the volume would drop. And nothing to do with super-capacitors or whatever.

Thing is a lot of these boom boom automotive things, they're often made out to be much better than they really are, e.g. power ratings of speakers. Like the OP's burned-out sub-woofer, many of these things are sold on Ebay and come directly from China. ...see also our sticky about off-brand and cheapo Android devices.