Re: Selling the Ampeg. What will I get now?


"JimmyM" <mmm@xxxxxxx> wrote in message
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On Thu, 19 Feb 2009 21:26:44 -0600, "Mike Rieves" <mriev@xxxxxxxxxxx>
wrote:


"coreybenson" <coreybenson@xxxxxxxxx> wrote in message
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"Mike Rieves" <mriev@xxxxxxxxxxx> wrote in message
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"Brian Running" <brunning@xxxxxxx> wrote in message
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The BorgMan wrote:

That is 1500W (or possibly 2400W) into a 2x12"... I'm unly running
1000W
into a 2x10".

No, it's not, and no, you're not. Those amps are capable of
delivering
that kind of power, but you're not putting it into the cabs. The
cabs
make a certain amount of acoustic output per watt of input power,
regardless of the output capability of the amp. If it takes 150
watts
to
make the sound pressure level you need, then it doesn't matter if
that
150
watts is coming from a 300 watt amp or a 50,000 watt amp.

No, Brian, you're forgetting that we're dealing with music, which is a
constantly varying signal with a large peak to average ratio, and there
is
a
need for headroom to allow peaks to be clean and unclipped. If your
average
sound pressure level can be accomplished with 150 watts, you'll need
1500
watts or more to insure that peaks are not clipped. It isn't uncommon
to
see
the peak indicator on a high powered amp lighting even at moderate
volume
if
the music is very dynamic in nature.

You're being sarcastic, right? Trying to make a funny? Or do you really
believe what you just wrote, Mike? I'm just checking...
--
Corey Benson

Wait, are you disagreeing that live music typically has a peak to
average
ratio oif at least 10 dB?
Perhaps you should do a bit of research before you say anything further. I
have and I've found that, depending on the type of music, peak to average
ratios of 10 to 20 dB are quite common. Since 10 dB is ten times and 20 dB
is 100 times, that means that you'll require an amp with at least ten
times
the average power level you're running to avoid clipping on the peaks.
With
guitar it doesn't matter that much because distortion is an effect, but
with
a bass, most players want a clean sound, and that's why the guitar player
can use a 50 to 100 watt amp, but the bass player usually wants 500 watts
or
more.

That's so bizarre I don't know where to begin. 10 db is ten times
what? 20 db is 100 times what? What the ***?

SPL, sound pressure level. If a band's average sound level is 90 dB SPL,
peak levels will be 100 dB SPL to 110 dB SPL. Since SPL is a power level, dB
ratios corespond directly with amplifier power levels. If you're playing at
50 watts average output, you'll need at least 500 watts to stay relatively
unclipped on the peaks. That's a 10 dB increase. 10 dB is a ratio of 10:1 if
you're using 50 watts average, you need 10 times that power, 500 watts, on
the peaks to avoid clipping on the peaks.
There's nothing bizarre about it, it's a fact of life if you're playing live
music. I've seen bass players here talking about using 1000+ watt amps, and
it isn't because they're playing at 1000 watts all the time, it's because
they need lots of watts to stay clean on the peaks.

Wow, my mind is totally blown right now. Sorry...I need a break.

Cool, take a break and think about it. :-)


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