Contour Enthusiasts Group Archives Forums Modifications Audio Receiver Amp vs. External?

I've never really got interested in car stereo stuff before, but I need some info before I start replacing my components.

Is there any difference between the 20w RMS coming from a head unit, vs 20w RMS coming from an external amp? I know there'll be lower distortion from the external amp, but what else?

------------------
Stephen Pechkoff
'95 Contour GL Duratec MTX, Electric red. AKA: "Connie the Stripper"
Dynomax, KKM, TH plug, Brembo discs, KVR Carbon Fibre pads
No resonator, SE Suspension, SE 7-spoke alloys.

yes. most defnitely. the wattage isn't really what you're looking for in an amp when comparing similar numbers. what you really want is often called "headroom." the amount of power the amp will drive over a particular frequency range. a receiver can produce 20 watts RMS, but is it over the whole frequency range (20-20000 Hz) or just the mid frequencies (400-10000 Hz)? if you don't have the power across the entire audio spectrum, you'll get audible clipping in the areas where the amp is less likely to perform according to spec (usually bass notes). generally receivers use smaller and cheaper components than external amps, this often contributes to a smaller effective bandwidth and a smaller amount of "headroom."

for example, my Pioneer receiver is supposed to provide 30watts of power RMS over 4 channels. my Alpine amp is supposed to do the same, but the Alpine is noticably more accurate than the Pioneer. stronger bass, cleaner highs, and smoother mids. that's what separates the men from the boys, i guess.


[This message has been edited by baco99 (edited June 28, 2000).]

[This message has been edited by baco99 (edited June 28, 2000).]

Thanks. I'm either looking at a Kenwood or Pioneer head unit, each with over 20W RMS, but they don't give any information on the power output at the frequency extremes. I guess I'll have to go and listen to a few.

i agree, listening is the only way to really make an educated choice. both kenwood and pioneer have very similar archtictures, so i think you'll end up choosing by price and features. i've installed both, and i'm sure you'll be happy either way.

keep in mind line-outputs, though. just in case you want to add a sub (or subs) later. the more line-outs, the better, IMO.

good luck!

Another thing to consider is the audio distortion caused by the internal power amp. Since all the electronics in your receiver shares the same internal power source, during loud volume levels, the current draw from the internal power amp may "starve" the other electronics of power. Ever notice the illumination lamp in the receiver flickering to the beat of the music when it's cranked up? My Blaupunkt did that before I installed an external power amp. Food for thought.

Anyone replace the factory amp with a better 4 channel amp and use the same location? I think that would be great if I could cram a better amp into the same area. I guess I'd have to buy the bypass harness and cut it in half (to run to the new amp).

Eric-
If you can find a small enough amp (read; low wattage), it is possible to mount it in the factory amp location. The only thing you need to look out for is heat. Air circulation under the dash is weak at best and with the heater on, it can get downright hot.

yeah. behind the dash would be too cramped and hot, i think. under the seats or in the trunk provide the best heat dissipation.

also, don't short change yourself on cables either. regardless of where you place the amp, always get a good quality cable to carry the signal. if you get crappy cable, you might as well keep the stock equipment.

I'm getting my system installed tomorrow. It came to a little over $900 after the $50 Sony rebate ($120 labor and $50 for Monster Cables - ripoff there). The place pretty much matched www.carmedia1.com prices!

-Sony CDX-7050 (high pass filters for 5x7's and adjustable low pass for sub, plus has 2 other sets of preamps) = $211!!!

-4 Polk dx7 (3 way 5x7) for $102 per pair! I have not heard them, so I'm crossing my fingers - Contours (door mounted speakers) need good high end with hopefully no dead spots.

-Sony 552 amp for I think $120 or $130 (140W RMS bridged - as much as the sub can handle and enough for me).

-Sony 12" sub ($50 rebate for buying 3 Sony items. A so-so sub, but they all sound the same to me at the levels I'll be playing at).

-Sealed box, about 1.3cu ft. Sub + box = $150. Flatter response than ported boxes, and is smaller.

They did not carry the Sony CDX-8050, but it's $60 more anyhow. I'll upgrade to MP3 when they are under $300 and stick this in my wife's 95 Taurus.

I'll post when I have a few days to check it out...

nice. you'll love the polks.

congrats! i wish i could hear what it'll sound like!

-brian