dave@hp-pcd.UUCP (dave) (11/05/83)
#N:hp-kirk:5300010:000:725 hp-kirk!dave Nov 3 01:18:00 1983 I have purchased a set of Polk 10 speakers about 4 months ago and have found myself driving my 40 watt Kenwood Amp at Max vol much of the time. Problem: Who makes a decent Power amp for under $1500 which will drive these speakers loudly (> 100 dB @ 1.6m)? My impression is that I would need at least 200 W/ch in order to justify the trouble. Currently I am considering a Hafler DH-500 or an Acoustat TNT-200. The typical reaction I get from sales-people is that I'm out of my mind to want so much power for these speakers. Is this true? I've also been told that amp X's 50W is more than amp Y's 150W. How can this happen? Isn't a watt a watt? Dave Barrett Corvallis, Oregon (hplabs!hp-pcd!dave)
tom@rlgvax.UUCP (Tom Beres) (11/10/83)
RE: 200 watts necessary for Polk 10's????
Something is wrong here. I own a set of Polk 12-B's and a Hafler 200
(100 watts/channel as I remember) and have no problem producing
more than sufficient volume (and cleanly at that).
Perhaps I should add a disclaimer since loudness is subjective.
I get plenty of volume for my needs. However, I live in a townhouse,
which although it is well sound-insulated, curbs me from turning it up
to literally wall-shaking decibels. On the other side of the coin, I
have never had the volume control over 1/2 way, either, so there is still
plenty of power with which to shake the walls should I ever get the mind to.
The 12-B is a three-way system with 1 tweeter, 2 midrange speakers,
and 1 bass "passive generator". The Polk 10 is a smaller model using some
of the same or similar components. I would be really surprised if the
Polk 10 is tremendously less efficient than the Polk 12.
I would strongly suggest: (a) checking out your components apart from each
other, either by borrowing a friend's equipment and trying your components
in his/her system, or by bringing your stuff into a shop to be checked.
(b) going back to your stereo shop and having them demo the Polk 10's with
a 40, 60, 80, and 100 watt amp, to see just what its requirements are.
200 watts are certainly NOT needed!
- Tom Beres
{seismo, allegra, mcnc, brl-bmd, gatech}!rlgvax!tomseifert@ihuxl.UUCP (11/11/83)
> On the other side of the coin, I have never had the > volume control over 1/2 way, either, so there is still > plenty of power with which to shake the walls should I > ever get the mind to. > ... > (b) going back to your stereo shop and having them demo > the Polk 10's with a 40, 60, 80, and 100 watt amp, to see > just what its requirements are. > - Tom Beres > {seismo, allegra, mcnc, brl-bmd, gatech}!rlgvax!tom I agree with Tom's article, except for a couple of technical points. (1) The position of the volume control (usually) doesn't correspond to what percentage of available power is being used. That is, having the volume control at 1/2, or "12 o'clock" doesn't mean you are using 50% of the power amp's available power. It means you are using 50% of the available voltage gain in the preamp. What percentage of available power is being used depends on the output level of whatever source you're listening to (turntable, tuner, tape, cd player, etc.), the gain of the preamp (which is what the volume control controls), and the gain of the power amp. (some power amps have volume controls) Some volume controls are labeled "0-10", these are very misleading. Some are labeled in dB, which is much better. (for completeness, some are not labeled at all) The maximum power available (onset of clipping) probably does *not* occur when the volume control is turned all the way up. There is usually extra gain (just in case you need it, and to provide compatibility among various gear), so that clipping occurs somewhere before 'all the way around'. Due to the logrithmic(sp?) nature of the human ear, a small increase in perceived loudness required a large increase in power. Therefore any difference detected between an 80 Watt amp and a 100 Watt amp is probably mostly due to increased quality (lower distortion) rather than the slightly larger amount of available power. -- ) ( ) from the mildly opinionated keyboard of _)__________________ |OOOOOOOOOOOOOOOOOO| Dave Seifert |OOOOOOOOOOOOOOOOOO| ihnp4!ihuxl!seifert |_O_O_O_O_O_O_O_O_O_O_O_O_O_O_O_O_O_O|