Stereo questions

[S4Biturbo]

i don't know about how it is nowadays, but back in the "ole" days, Alpine
amps were rather bright sounding...first class head units and signal
processors though...
just my >02
----- Original Message -----
From: "TM" <t44tq at mindspring.com>
To: "'Ameer Antar'" <antar at attbi.com>; <quattro at audifans.com>
Sent: Tuesday, July 09, 2002 3:20 PM
Subject: RE: Stereo questions


> Damping factor and headroom have a great deal to do w/ this, the amp
> being
> able to control the current demands and supply the necessary current to
> the
> sub when necessary.
>
> I'm not talking about low quality crap like Pyramid, so let's just get
> that
> right out of the equation to begin with.
>
> Only a handful of car amps run class A, most of them are A/B, although
> there
> are quite a few class D sub amps now. Class A is also out of the
> equation for
> all intents and purposes.
>
> In order for the bass to be tight and well-controlled, the amp feeding
> the
> sub must be able to supply enough current to handle the peaks- if the
> amp
> lacks the headroom, it will sound bad, as you have said. Sub amps in the
> 250Wx1
> range @4ohms, 500Wx1 @2ohms is really the typical setup these days.
>
> I need a specific recommendation on a sub, otherwise, I'll just go get a
> JL 10W3
> and be done w/ it- probably have a custom box made to measure and
> that'll be it.
>
> As for head unit amps, they may be sufficient to power factory speakers,
> but
> if you're serious about getting halfway decent sound, even a mediocre
> outboard
> amp will kill the head unit in terms of SQ. My old Sony 60Wx4 kills any
> of the
> head units I've heard and it's a bright, crappy-sounding amp as far as
> amps go
> (overrated too, only benched at 53Wx4 @4 ohms). My current a/d/s 40Wx6
> is a much
> better sounding amp and according to raw numbers, is outperformed by the
> latest
> high-power Alpine head units (which put out 60Wx4, supposedly). I'll put
> my system
> up against the high-power Alpine all day long, no contest.
>
> Taka
>
>
>
> -----Original Message-----
> From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com] On
> Behalf Of Ameer Antar
> Sent: Wednesday, July 03, 2002 1:24 PM
> To: quattro at audifans.com
> Subject: RE: Stereo questions
>
>
> I'm not sure what you mean by 'control the woofer'? I'm guessing this
> means that the cone movement (and thus sound) is accurate to the
> original signal... The thing is, even if the speaker is rated at 1000W,
> a good quality low power amp will always sound smooth and controlled.
> The good amps have low distortion even near the max rating, especially
> those using class-A circuitry. Beyond that they will shutdown to save
> themselves. But the sound level will be much lower, esp. if the woofer
> is inefficient. Low quality amps will fart out the crappiest sounds near
> their max rating whether it's at 20W or 500W. Point is, sound distortion
> has more to do w/ amp + spkr quality than wattage. One thing about power
> is that there is a much larger difference in volume or dB between 1W and
> 10W than between 300W and 400W. dB's are in a logorithmic scale. So if a
> speaker is rated at 500W, 300W for an amp is reasonable, as long as you
> know where the limits are. (How loud do ya really want?) If you wanna
> greet you neigbors at the end of the street w/ your subs, then
> high-power, low efficiency subs will work great, but if you want to be
> more merciful on your car's electrics and your ears, medium power, high
> efficiency subs are the answer. Speakers w/ low Fs (resonance freq) will
> get those low organ notes out, as long as there is enough cone area
> (separate or combined).
>
> About head unit amps, they've actually come a long way since several
> years ago. Head units had the problem of only being able to use 12V for
> the audio amps, and many used cheap IC packs that had terrible quality
> and very low power. The problem was the 12V power was too low. An amp
> can only produce an output signal whose amplitude is less than half of
> the amp's voltage source (audio signal has a + and - portion). Outboard
> amps bypass this problem w/ DC-DC conversion which converts 12V to +/-
> 20-50V. So now the amps have plenty of source voltage to amplify the
> incoming signal w/o any distortion. Finally they've done the same for
> head units using miniaturized electronics to convert 12V into some
> higher +/- voltage. MOSFET's are very good at doing this b/c they're
> highly efficient and run at high frequencies. That's why you often hear
> things like MOSFET's in the newer head units and they've been used all
> along in outboard amps. Although I wouldn't recommend using a head unit
> to power a sub, the fact that it is possible and that it sounds very
> reasonable, proves that they can be useful, if at least used to power
> small drivers above the subwoofer freq. range. Of course, there are many
> advantages to using outboard amps, esp. w/ subs, but head units aren't
> as bad as they use to be...
>
> -ameer
>
>
> ---Original Message---
> --__--__--
>
> Message: 8
> From: "TM" <t44tq at mindspring.com>
> To: "'Audi Quattro'" <quattro at audifans.com>
> Subject: RE: Stereo questions
> Date: Tue, 2 Jul 2002 23:01:17 -0400
>
> Brad-
> No, I have not considered two 8"- the bass extension is not enough IMHO
> to make it worthwhile.
>
> How much power were you running to the speaker? You need a lot of power
> to control the woofer properly- I have this problem at home, feeding
> only a measly 60W to my speakers when they really need 200W or more to
> properly control the woofers and keep it from getting too boomy.
>
> IMHO, 100W RMS is not enough to run dual 10s. I'm planning on feeding a
> DVC sub 160W to each coil, total 320W RMS and that's still somewhat
> underpowered.
>
> If I had a monoblock amp, I'd use it, but I already have this amp, so
> that's why I'm not feeding it more. I'd go w/ something like the JL sub
> amp- 250Wx1 at 4 ohms, goes to 500W at 2 ohms, that would do very nicely
> feeding the sub, but I have the amp I'm using already.
>
> I've not heard of many car speakers running 8 ohm- standard load is 4
> ohms.
>
> I plan on using a small sealed enclosure for a single 10 and from what
> I've heard so far, the JL 10W3 is not a bad SQ sub. Kickers are not
> known for SQ, nor are Cerwin-Vega, two of the other suggestions I've
> gotten.
>
> Taka
>