hello,

i'm helping a fixed installation situation get better over time. they
don't have money to do it all at once.

i want to get a crown 800 power amp, and run it into their existing
speakers. their speakers are wimpy and not used to seeing more than
100 watts.

so i'm hoping i can just keep the amp turned down low until more
powerful speakers can be installed.

will that be ok?

wrote:

hello,

i'm helping a fixed installation situation get better over time. they
don't have money to do it all at once.

i want to get a crown 800 power amp, and run it into their existing
speakers. their speakers are wimpy and not used to seeing more than
100 watts.

so i'm hoping i can just keep the amp turned down low until more
powerful speakers can be installed.

will that be ok?

Probably not. The level control simply adjusts the amp's sensitivity for
full output.

If you put in a bigger signal ( such as drive the mix harder ) then you
still get the full watts. It's *not* a 'power control'.

Graham

If you put in a bigger signal ( such as drive the mix harder ) then you
still get the full watts. It's *not* a 'power control'.

Put a resistive pad on the outputs, perhaps? If you waste most of the
wattage in heat...

In article .com writes:

i want to get a crown 800 power amp, and run it into their existing
speakers. their speakers are wimpy and not used to seeing more than
100 watts.

so i'm hoping i can just keep the amp turned down low until more
powerful speakers can be installed.

will that be ok?

Sure. The knobs always go down. Rememer, though, that when more
"powerful" speakers are installed, you'll have the potential to make
it too loud. Be careful. You may not ruin the speakers, but you might
lose your audience.

--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

On 27 May 2005 16:20:43 -0700, wrote:

hello,

i'm helping a fixed installation situation get better over time. they
don't have money to do it all at once.

i want to get a crown 800 power amp, and run it into their existing
speakers. their speakers are wimpy and not used to seeing more than
100 watts.

so i'm hoping i can just keep the amp turned down low until more
powerful speakers can be installed.

will that be ok?

Yes, if you are careful. If you will have other operators who are not
careful, try this procedu

Turn the big amp waaaay down.

Put on a CD with some clean instrumental tracks where you will hear
distortion easily (Steely Dan, Night Fly?).

Turn up the mixer until the meters are in the red and you just start
to hear distortion in the speakers due to clipping in the mixer.

Turn up the amp to a maximum safe level for the speakers. You might
want to use an AC RMS voltmeter on the output to measure the average
power to the speakers.

P = V * V / R
Power = Voltage squared, divided by total speaker impedance in ohms

Tape and mark the knobs on the amp to discourage anyone from turning
it up further.

Someone could still fry the horns out of the speakers by turning up
the mixer into extreme clipping, but that's always a risk, even with
well-matched speakers and amp.

Mike T.

In theory this should work but consider what happens when a signal
gound is lost and 800 Watts of 60 Hz. line noise is applied to the
speakers. Uncontrolled feedback could be fatal also.

there's little danger of someone turning up the knobs. the amp is in a
large locked cabinet, with a master power kill switch outside the
cabinet.

wrote:

there's little danger of someone turning up the knobs. the amp is in a
large locked cabinet, with a master power kill switch outside the
cabinet.

Lucky, 'cos if there's DJ around..... ! ;-)

I once came across a situation where a DJ had selected 'bridged' on an amp
( without making any of the other necessary adjustments ) as he'd heard it
made the sound louder. The out of phase bass in the left and right channels
was what caused the venue owners to ask me to come and check out the 'odd
sound'.

There's kids out there who truly don't even have half or even a quarter of
a clue.

Graham

In article writes:

I once came across a situation where a DJ had selected 'bridged' on an amp
( without making any of the other necessary adjustments ) as he'd heard it
made the sound louder. The out of phase bass in the left and right channels
was what caused the venue owners to ask me to come and check out the 'odd
sound'.

Well, it's good that at least someone there could tell from the sound
that there was something wrong. At least there was no telltale smoke
in this situation.



--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

Too true. And every DJ or musician thinks they are a sound engineer by
default.

You could offer the venue owner a job though - phase mis-alignment
isn't the easiest thing in the world to hear (in my experience about
75% of people can't even hear it).

In answer to the original question though - you say the speakers are
"used to seeing" about 100watts - is this per speaker, and if so how
many are there?

Crown have a tendency to power rate their amps at 2ohm impedance loads,
where *most* speakers are 8ohm. this would translate to roughly
400watts, split into 2 8 ohm speakers, so about 200watts per speaker,
which is not a bad power rating for a 100watt rated speaker (most
speakers can handle transients up to twice or 3 times their RMS spec -
the thing that destroys speakers more quickly than anything is
distortion which you are more likely to get with an underpowered amp -
or a mentally challenged DJ who thinks red lights are pretty).

Of course, if there are 2 or more speakers for each channel, you could
also connect them in series instead of paralell, giving a 16ohm load at
the amp output instead of 4, and another drop in the total power.)

BUT - as I said, the thing that will destroy your speakers is
distortion (you can burn out the coils by overpowering too, but
distortion is much more of a problem), and distortion is most likely to
be introduced before the signal ever hits the amplifier. Keeping the
amp turned down can limit this to some extent, but best practice would
be to educate the people using the equipment (mostly DJ's I assume),
and impress on them the benefits of unity gain (0db signal levels) from
their DJ mixer. I find a stick with a few nails in it to be the best
method generally...:-)