TXTA

iTrader: (3)

Okay, I have a 1994 Trans Am. Here are the speakers I am already going with for sure:
Focal Polyglass 165v components
Alpine Type R 1041-d 10" sub in a stealthbox

The focals RMS is 75w x 2 and a peak of 125w x 2
The Alpine RMS is 300w X 1 and a peak of 1000w X 2

I have decided to go with Phoenix Gold Octane amps to power this setup. I want to run two amps, one for the components and a mono for the sub. here are the amps I am trying to decide between. Please feel free to persuade me.

For the components:
R2.5:2 = 80w x 2 @ 4ohm stereo for 112.95
R4.0:2 = 125w X 2 @4 ohm stereo for 146.99

For the sub:
R5.0:1 = 500w X 1 @2ohm mono for 194.00
R8.0:1 = 400w X 1 @4ohm or 800w X 1 @2ohm mono for 244.50

please let me know guys. I don't know whether I need to run them closer to the RMS or the middle of peak? I am kind of leaning towards the R2.5:2 and the R5.0:1, but please let me know.

01WS6/tamu

iTrader: (37)

Run the 8.0 and the 4.0. Both amps have more power yes. But the more power a amp makes it is generally cleaner power. Smaller amps trying to do more than they are designed get noisy and cause distortion. Where the bigger amps can play clean and loud all day. Distortion is what destroys speakers not high power. Set the gains and the crossovers correctly and the system will play loud and long for years to come reliably. Also use the factory head for a doorstop. Even if it is not expensive the output stages of an aftermarket headunit are far superior to the factory. Try to get a head with front rear and sub out it makes life tremdously easier.

TXTA

iTrader: (3)

Well, I have a CLarion Pro Audio reciever to go in also.
Thanks

firebirdude

That has nothing to do with the amp. That comes from uneducated people trying to push their smaller amp too far and forcing it deep into clipping.

TXTA, go with the R4 and R5. As 01WS6 was trying to point out, you'll obviously be able to get more clean power out of the R4. Less chance of you wanting to crank the gain **** for an increase in juice. Give those Focal's the power to scream. Think about 6 months from now..... you'll wish you spent the extra $30 freakin bucks for the extra kick. And the R5 should be plenty for a single Type-R in the stealth. And it's not like you'd even have the ability to add another sub with the R8. Your sub has dual 4 ohm voice coils. With two, your choices are 1 or 4. Not gonna work with the R8. Save the couple bucks because 500WRMS is plenty for the single sub. Oh and just a note. Peak power ratings are worthless to you and me. They are only good for printing on the side of the box to make the amp look bigger to the untrained eye.

tuffluck

iTrader: (4)

personally i'd go with the 8.0. i think you'll figure out, from owning an f-body, that the higher you turn your gain on your amp, the more noise and rattles you'll here, heh. but if you don't mind fixing them slowly, you have a long way to go on your gain. in other words, you can just leave it at a reasonable bass level with minimal rattles, or you can turn it up to gigantic proportions later on

i'm running a 400 watt amp to my sub, and i'm also running about 60 watts to my front stage, and that combination is pretty good. if you push your fronts to 125, and then your sub is at 500, you'll wind up leaving the gain on your fronts down a bit, because the higher the gain on those, the higher the gain will need to be on the sub amp to match the bass with the mids. in other words, i think the 80 watt amp will be just fine

Bumpin' Yota

100% false. That is THE biggest fallacy in the car audio world going around. Go put a RF 100g2 on a DD9917 and I'll suck your nads if you can make that 9917 blow on that amp - because you won't make that sub blow.

There are only 2 ways to render a transducer inoperative, that is to delaminate the copper or aluminum coil from the former or to physically tear the suspension. You do the former by applying too much power, and you do the latter by exceeding the spider's/surround's linear throw capability.

EXCESSIVE POWER KILLS SPEAKERS here is why:

A voice coil has a thermal limit. Once that limit is exceeded the glue holding the coil together and to the former melts and the coil will delaminate. Once delaminated, the wire will then get pinched between the gap and the former, then ground to the polepiece or topplate, and likely take the amp with it. All of that can happen in seconds too...

Now what generates this destructive level of heat? The transducer's own inefficiency. Typical transducer efficiency is less than 1%, so that 1kW you might feed a subwoofer will be converted to less than 100 watts acoustical energy and the rest of the power (900+ watts) is converted to heat. That heat must be dissipated by the voice coil and former.

Distortion is any sound added to the system outside of the origional recording and has no bearing upon the amount of heat the coil must dissipate.

Clipping is the term used to describe the wave form from an amplifier when it is severely overdriven. Typically distortion accompanies clipping as the amplifier is usually very stressed during clipping. If you were to look at clipping on an oscilliscope it would look like a sineusoidal wave with the tops and bottoms cut off.

What bearing does this have?

Well the area under the curve is the power applied, so turning up your gains increases the sine wave's amplitude. When you turn the gain too far the amp will become overdriven and will not be able to reproduce the perfect sine wave. When the internal rails and fets of the amp cannot supply the necessary voltage and current, the amp will clip the tops and bottoms off of the wave. If you were to look at the area under the curve when clipped versus not you'd see that there is a LOT more power applied.


Again distortion does not generate heat, power does, and a coil can only dissipate so much before the temperature exceed the glue's thermal melting point (~500*F) Clipping generates more power than unclipped in the same amp, and distortion is usually present when clipping is present.

Just an FYI from your mobile audiophyle, lurker, and F-body lover!

Bumpin' Yota

Nice mid/highs with the focal. As far as amps I really suggest Zapco c2k series amps. A 2.0 and 4.0 would work very well. The one drawback would be the price of Zapco amps.... Then a box/sub upgrade would be in order after the new amps.

firebirdude

Good info Bumpin'. I have had many similar arguements on these boards.... possibly even this exact board.
Sooo... get the 8.0 with more power, to PREVENT rattles? That doesn't make any sense. So you're saying just the fact the gain is cranked causes the rattles... be it on a 50W or 50,000W amp? Now what kinda sense does that make? Come on. Honestly.