G35 Stereo Head unit installed - Speakers seem quiet

[srv2nv]

I installed an Alpine head unit in my 03 sedan (originally with the Bose system) and since then I've noticed my interior speakers seem a little quieter than before. I've done what I could with changing the settings, but that gave little to no help. When I had my Pioneer head unit with 3v RCA's it sounded a lot better, but my new one is only running 2v RCA's to the fronts and backs. Is there something I can get to help bring the life back into my speakers?!I really don't want to go to the next step yet (complete swap/upgrade of amp and speakers) as I don't have the time right now to tackle the task, so I'm hoping there might be a quick fix or something that I may have missed. Any ideas would be great.

[joe603]

To be clear, you replaced the OEM head deck with an Alpine deck...but before the Alpine you had a Pioneer?

I would say that the Alpine is to blame. The bose amp is looking for a higher signal level. There may be a gain control on the amp...but you'll probably need to replace it.

I've never had good luck with Alpine...and wouldn't recommend it to anyone. I prefer Kenwood Excellon...

[smockers83]

Are you still running the Bose amp or an aftermarket amp? And what Alpine unit did you buy that only has 2 volt RCA?

[srv2nv]

Sorry, to make myself a little more clear (I wrote that in a rush before work), I replaced the factory radio with a Pioneer head unit but didn't like the look and feel of the controls so after a couple of weeks I replaced it with an Alpine CDA-9885 (I believe, don't quote me) since I had nothing but joy with my old Alpine HU in my Prelude. But right away I noticed the speakers didn't have as much life to them as before.

I am still running the stock amp and speakers that were installed in the car from BOSE for my internal speakers.

I figured the amp was wanting more from the HU, and that possibily the difference between the 3v and 2v was to blame. I thought I read somewhere before about some kind of adapter piece that was needed to send the signal properly to the amp, but unfortuantly I'm unable to find anything about it now.

*EDIT*

After doing some research, it turns out the HU has 4v Pre-outs (don't ask me where I got the 2v number from, its been a long couple of weeks). But that just brings me back to being even more stumped on the situation.
Modified by srv2nv at 1:36 PM 8/11/2008

[joe603]

Do you still have the Pioneer deck? I wonder if the 4V may have done something to the Bose amp. Try swapping the Pioneer back in to see if the problem goes away. Another possibility is a faulty Alpine deck...did you buy it online??

[srv2nv]

I still have the Pioneer deck, unfortuantly its installed in my girlfriends Crapfire though.

Thats a good idea though, I'll talk to a few friends and hopefully find someone with a different HU laying around that I can quickly swap in to test. If that doesn't work, then it looks like the only other route would be a complete speaker/amp upgrade.

[smockers83]

Well, if you're still using the Bose amp, you wouldn't be using the RCA pre-outs, so what the voltage is doesn't really matter, unless I'm mistaken on the setup. Alpine always builds their units with a lower RMS rating for whatever reason, especially compared to Pioneer. Whether that's due to Pioneer using MOSFETs, I don't know. I've owned both Alpine and Pioneer units (not the ones you have) and I liked Alpine better, but I always recommend Pioneer or Alpine (I hate the styling of essentially all Kenwoods).

[C-Kwik]

If the stereo's built-in amp is 2-ohm stable, then I'd just bypass the Bose amp altogether. If not, the other option is to swap out the speakers to 4-ohm and run them directly off the headunit.

The rear speakers may be interesting though as there are 4 of them. Wiring them all in parallel would drop the total resistance to 1-ohm. You might have to run them in series and bring it back up to 4 ohms. Makle sure the deck is capable of running at 2-ohms if you are going to try this. Dropping the speaker resistance will cause the deck's built-in amp to run hotter.

[srv2nv]

I am running the front and rears off the front and back pre-outs on the HU since the wire harness that came with the kit connects the interior speakers that way.

I have always had Alpine head units up until the Pioneer Premier I originally bought for my car due to a friend recommending it. After about a week of using it, I couldn't take the odd knob control, constant beeping and poor automatic slid out face plate anymore and went back to my brand of choice, Alpine. Unfortuantely for some odd reason, its not able to push the BOSE amp like the Pioneer with its 5v pre-outs.

[smockers83]

You really have me confused. The Bose amp, from looking at wiring diagrams, doesn't do RCA, its all wire harnesses. Those volt ratings are only for the pre-amp outputs, the RCA outputs, not the wire harness. The reason its quieter than the Pioneer is because of the lower RMS. Alpines usually are around 18x4 RMS and Pioneer around 20 I think. Actually, I just looked up some Pioneer units and they're rated at 14 watts RMS, only the low-end units have 20 RMS (used to be that Pioneer always had high RMS ratings). So I guess the question is, what Pioneer unit you had in beforehand?

[srv2nv]

The wire harness that came with my kit came with 2 wire harness's. The one had power/ground/remote/etc on it and were wires, the second one had 2 sets of RCA's (blue, green, purple and yellow). Nice color choices, I know, but it came with a guide for which was which (ie. blue = F/L, green = F/R). They connected to the plugs that were in the dash that were originally connected to the stock radio. When I installed both HU's, I simply connected the wire harness to the front and rear pre-outs on the HU like the instructions said to. From my understanding of the instructions, there wasn't any other way of running the interior speakers from the HU without rewiring the entire car.

I'm not exactly sure which model number it was, but it was a Pioneer Premier 6XX-BT or something like that, 2007 model. I was running the interior speakers off the front and rear pre-outs with that HU installed as well.

[smockers83]

Ah, ok. Interesting. The higher voltage doesn't really change sound levels anyway, it just provides a cleaner signal for the amp. So why its softer with the Alpine, I'm not really sure, but its something with the Bose amp.

[srv2nv]

Well I'm going to give it a try with a Pioneer (hopefully Premier again) installed to see if it brings the life back into the speakers. If it does, I'll possibly try with a different model of Alpine to see if my Alpine HU is the problem, and if that doesn't work, than my plans of a speaker/amp overhaul will probably have to be done a little sooner than expected.

Hooray for getting to install something!

Boo to the amount its going to cost me.

[joe603]

Well, I hope you figure out the problem...I really don't care for Alpine. I had a deck that gave me nothing but problems.