RE: Re: Amp/speaker recommendations?

["Keith Doxey" <ukha@xxxxxxx>]

Hi Tony,

60W will be fine. you will probably find you dont go above 10W anyway.
After I saw your posting I looked for Stereo HiFi amps and the power levels
seem really low now. I have a couple of Stereo Hifi amps, one Technics and
one Memorex. Both cost less than £180 when new and are rated at 100W per
channel. As you say, power levels of 100W p.c. are almost standard for AV
amplifiers so it seems strange that the stereo ones have dropped in power.

Because sound levels are logrithmic you get some very strange facts.

Doubling or Halving the power only changes the sound level by 3dB
(see how much difference it makes on your stereo if you disconnect one
speaker.)

To double the percieved volume requires a 10dB increase in power or 10
times
the power so a 100W amp is only twice as loud as a 10W amplifier.

<SAD GIT MODE>

For the first 10 years of my mobile disco I only had a 2 x 100W amplifier
and only twice was I running flat out despite playing quite large halls.

Even our local "Tiffanys" [capacity 1500] (was part of Mecca's
national
disco chain) only had a 600W (VALVE) system in the mid to late 70's and it
was always loud.

Then "House Music" hit the charts with huge amounts of sub bass
and I
started fitting 2kW systems in pubs. You wont need to go to those power
levels in your showroom unless you want the "background" system
to be
capable of hitting 115dB though :-)

</SAD GIT MODE>

<REALLY SAD GIT MODE>

Amplifier powers seem to have gone crazy now. Back at school I can remember
looking up obscure things in the Guiness Book of Records. One thing I
always
used to check was "Worlds Most Powerful Sound System".

The record was held for several years by Ontario Speedway Track with a 20kW
system.

Round about 1975, Led Zepplin did a concert at Knebworth and stole the
record with a 50kW system.

Last year I saw a documentary about U2 and they had a ONE MEGAWATT sound
system!!!

Likewise speaker ratings. When I started DJ'ing at Youth Club, the 12"
speakers in our cabinets were rated at 15 Watts. My first pair of 12"
speakers were Fane Pop33T (33 Watts) and my disco cabinets were loaded with
2 x 12" Fane Disco 80's (80 watts). Now you can get 12" speakers
rated at
600W RMS not the mickey mouse ratings used for cheap stereos and car
stereos.

Maplin once listed a "1200W Sub Bass Speaker". Power
Handling:1200W (200W
RMS). Going by that mathmatical formula, the 900W amp in my loft is really
a
5.4kW amp. Pretty amazing it can run off a 13A socket then!!

</REALLY SAD GIT MODE>


Keith

www.diyha.co.uk
www.kat5.tv


> -----Original Message-----
> From: Tony Butler [mailto:lists@xxxxxxx]
> K, ta.  Do you think 100w is about right, or would smaller do
> (it's a fairly
> big showroom, but as you say, volumes will be fairly low).
> Having problems finding reasonably priced stereo amps with that power.
> A couple of hundred quid will get me a 40/60 watt stereo amp
> or an a/v receiver
> with 5x100W - go figure :/
> Don't want a surround amp coz they tend not to sound so nice
> IME, for just
> music.....
>