: My stereo sounds better when I remove the key from the ignition - audio help!



perfect
05-17-12, 09:34 AM
Hey everyone.

My 05 V had a previously installed stereo when I bought it - dual subs, single amp, wired via a LOC from the output of the original subwoofer. Everything sounded great but I recently decided to reclaim my trunk and removed the aftermarket subwoofers and amp.

The car sounds "good" while I'm driving - but I realized the last few days that when I shut the car off and pull my key out of the ignition (but don't yet open the door) that the bass sounds more full and deeper.

I'm starting to think that my rear deck subwoofer (the stock one) isn't actually playing while the car is on. Which would be strange, but maybe with the aftermarket stereo it was somehow bypassing the stock amp.

Does anyone know where the stock amp accessory fuse is?

The only other pertinent piece of information to help clue this in is that I've noticed this while using my iPod connected to my USA-SPEC PA15-Vette iPod interface.

RADEoN
05-17-12, 01:56 PM
the best way to check and see if there's any issue with the sub is to:

1. Download (http://www.realmofexcursion.com/audio/testtones/45Hz.mp3) a 45hz test tone, and burn it to a disc. (This will help narrow out any issue with the iPod connection)

2. Get a multimeter and set it to A/C voltage. Touch the terminals of the multimeter to the speaker terminals, it will not matter about lining positive and negative together.

3. Start the car, and play the sine wave, and check where the voltages are at during playback, now shut the car off and do the same thing. If the voltages increase, then you have an issue, but if not, then (as I suspect), it's all a mental thing. You could also copy the mp3 file to your i-Device and play it back doing the same thing to see if there's an actual issue.


Now, if the voltages from the stock amplifier are different with the car switched off and on, it could mean a broad range of things, from things I don't know exist, to maybe an alternator struggling to charge the battery while also powering the amplifier (as opposed to it just running strictly off of battery power), to a poor grounding issue that's eliminated when the car isn't moving, etc.

FoD
05-17-12, 03:06 PM
Could also be no exhaust tone after you turn the car off.

GDPossehl
05-17-12, 04:23 PM
The ambient noise from the running engine is the real culprit. Same deal with your tv in the living room if there's a conversation in the kitchen. You'll turn it up to hear better.

Your voltages should be different when shutting the car off. Voltage at the battery will drop from 14v to about 12.5v because the alternator is no longer charging it.

perfect
05-18-12, 04:10 PM
Ok - so new development. I watched the radio closely when I take the key out of the ignition (but keep the door closed) and noticed that the EQ is changing.
It's more strange than I thought because this only happens on my XM channel (where I have my PA15-VETTE iPod adapter hooked up). I'm to call USA SPEC this afternoon and discuss what's going on to see why when I plug in my iPod the CTS-V stock radio seems to default to a neutral EQ (no bass, no midbass, etc).

For those of you with a PA15-VETTE, it's interesting to note that this only happens when I set the iPod to be in "Direct Mode".

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Could also be no exhaust tone after you turn the car off.

thought that as well - but I confirmed it's not just in my head. If I take turn the car off (but leave the key in the accessory position) than it sounds dull and flat. When I actually pull the key out of the ignition is when it immediately jumps to a "better" sound.

Strange...

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The ambient noise from the running engine is the real culprit. Same deal with your tv in the living room if there's a conversation in the kitchen. You'll turn it up to hear better.

Your voltages should be different when shutting the car off. Voltage at the battery will drop from 14v to about 12.5v because the alternator is no longer charging it.

Same thought as FoD's