JAXFLTSX

Does anyone here now the power rating for each channel on the factory AMP?

vidgamer

Not that I want to speak for Elduderino, but I think he told me that it had 8 channels using IC chips that were hooked up like they would be in an average head-unit. So, probably something like 18w RMS? Well, it's a good rough figure.

So, wow, 18 x 8 sounds like a lot! Well, except that normally you can drive both mids and highs off of the same channel, so, I'm not sure how much you gain by having them on separate channels. (How much power does a passive crossover sap anyway?) And for bass, 18w, even if x2, isn't a lot either.

Having said that, I have to admit that the stock system will crank louder than I'd want to listen.

elduderino

I would estimate it at 18W at 1kHz at 1% distortion. I'm sort of pulling that out of my ass, but then again, where do YOU think the numbers on the side of the box come from? : )

I'd estimate it at about 12W at about 5% THD at 20 Hz.

CJams

Thats a compact little 144 watt amp.

vidgamer

One problem is that it isn't using those 144 watts efficiently. For one thing, even with normal head units, you can drive both a woofer(mid) and tweeter with one channel. Here, two channels are used. Is there any advantage to that?

I recently went shopping for aftermarket decks (for someone else) and picked up one for $135 that had something like 22w/ch RMS, I think it was? 50 peak! Of course, if you actually got 50w out of it, it'd sound like crap, but it lets them market it as a "200 w" amp. Bleah.

Elduderino also mentioned to me that one reason that the stock amp sounds so loud is that the stock speakers are efficient. Well, speaker efficiency does matter (when you're on the low side of wattage). I'm not sure if he mentioned the efficiency of the avincar kit speakers, except for the tweeter. I'm hoping that having a lower efficiency tweeter isn't crucial.

On one of my cars, I put in some half-way decent Infinity speakers, only to find that I couldn't drive them as loud as I wanted with the stock deck. That's what a low-efficiency speaker will do to you! You'll run out of headroom sooner.

So, I guess my point is that the stock amp is probably enough as long as you have enough headroom for the volume you prefer. You only need "enough". If you need more than that, then you will need an amp (or more efficient speakers, all else being equal). Although, I always figure that bass requires a lot more energy; if I have a problem using the stock amp, it's probably going to be "not enough boom". We'll see...

elduderino

Actually, I may have communicated unclearly.

Many efficient speakers are light and flimsy and use lighter parts that are lower in quality mechanically. So most high-efficiency speakers have non-linear distortions (regardless of what Cerwin-Vega says: )

The stock amp's power rating is WITH headroom, by the way. The reason they use that mahny channels is that to have 18W on 8 channels is a HELL of a lot cheaper than to have 36W RMS on four channels. You need real output transistors (or you SHOULD), you need a real switching power supply, which leads to a real heat sink due to heat dissipation requirements. So that's why they did this. THe CL-S amp is much better by comparison.

vidgamer

Oh yeah, I didn't mean to imply that "high-efficiency" meant "quality". It just is one factor. I've noticed that some of the best speakers have a relatively low-efficiency.

On my last car, I bought speakers that were regarded as good quality (plus sounded good to me, at least on the ol' demo board), but had a higher efficiency rating than most. I still ended up adding an amp! I still seemed to want to crank it higher than they wanted to go.

Those were Boston Acoustic Pros. While adding an amp improved their sound (even when not playing loud), I do think that they were a tad harsh (probably the tweeter design). I'm glad to be going with a silk tweet this time around.

Is having two 18w channels the equivalent of one 36w channel? (Aside from the issue of lower-quality components....) I would have thought that 36w would be better in that you could drive both a tweet and mid, and they'd both be getting "36w" (except in the crossover region, I suppose, but let's not get too picky ). But if two 18w channels can be significantly better than 1 channel (driving both speakers), then I'll be glad to take what I can get.