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input sensivity / headroom on amplifier



 
 
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  #1  
Old December 22nd 03, 01:12 AM
Marco Gaudesi
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Posts: n/a
Default input sensivity / headroom on amplifier

hi

i've a question about the input sensitivity of the amplifier electrovoice
P3000

data sheet EvP3000:

www.electrovoice.com/electrovoice/EVfiles.nsf/lookup/P3000/$File/p3000-eds.p
df
( ..../p3000-eds.pdf )


input sensitivity=0dbu (0,775 Vrms)
maximum input level=+20 dbu (7,75 Vrms)

i have two meter before the amplifier input:
-Rms Vu meter that display 0dbVU whit a 1 khz sine @ 0 dbu
(max display=+3dbVU)
-Peak led meter that display 0db whit a 1 khz sine @ 0 dbu
(max display=+24db)

i work in live (much peak and not much rms), so i wish to put a
maximizer/compressor @ L/R, after the maximizer a
RMS limiter ([email protected] dbu), and after all a peak limiter ([email protected]+19 dbu)....
..... al before the meter (Vu and Peak), so i can keep under control in every
time the signal that go to the EvP3000, a signal where the rms don't go up
0dbVu and peak don't go up +19db.

what did you think about this?
is a correct way to take the full 1200Wrms @4ohm from the Ev3000
without distorsion, or a stupid way to crash all the system?

thank's a lot, and excuse my very bad english.

marco



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  #2  
Old December 22nd 03, 07:51 AM
Peter Larsen
external usenet poster
 
Posts: n/a
Default input sensivity / headroom on amplifier

Marco Gaudesi wrote:

> i've a question about the input sensitivity of the amplifier
> electrovoice P3000


> input sensitivity=0dbu (0,775 Vrms)
> maximum input level=+20 dbu (7,75 Vrms)


This appears to mean that with input level control all the way up it
will produce rated power with 0.775 mV input signal and that it with the
input volume control turned all the way down will require 7.75 volts
input signal.

> i have two meter before the amplifier input:
> -Rms Vu meter that display 0dbVU whit a 1 khz sine @ 0 dbu
> (max display=+3dbVU)
> -Peak led meter that display 0db whit a 1 khz sine @ 0 dbu
> (max display=+24db)


Aha.

> i work in live (much peak and not much rms), so i wish to put a
> maximizer/compressor @ L/R, after the maximizer a
> RMS limiter ([email protected] dbu), and after all a peak limiter ([email protected]+19 dbu)....


First tell us what music this is about, if you reinforce natural sound,
then why change it, why not simply reinforce it?

> .... al before the meter (Vu and Peak), so i can keep under
> control in every time the signal that go to the EvP3000, a
> signal where the rms don't go up
> 0dbVu and peak don't go up +19db.


All that matters in terms of clipping is peak level. Most of what
matters in terms of loudspeaker damage is average level. In terms of
hearing damage protection: what works best to prevent hearing damage is
to turn the volume down to sane levels.

> what did you think about this?
> is a correct way to take the full 1200Wrms @4ohm from the Ev3000
> without distorsion, or a stupid way to crash all the system?


*IF* I understood the specs right above - and I am not sure I did - then
you turn the amp all the way down, connect a mixer that conforms to
standard audio levels - most do - to the input and rely on the amps own
internal limiter to prevent it from clipping and keep the sound well
clear of the red range on the meters. But from the description of the
constant gain mode one would generally use this amp in that "constant
gain mode" and with the input signal suitably matched to prevent
clipping. The very point of having so large an amplifier is to avoid
running it near clip-level.

> thank's a lot, and excuse my very bad english.


Your english is fine, but your thinking appears to be unclear and the
aim, the context, of the amps use is undefined. If you need to use
compression or limiting to "get it louder", then you need more sound
equipment anyway, because using compression/limiting to make things
louder without clipping can, not will but can, depending on
circumstances, increase the risk of loudspeaker damage rather than
decrease it.

Perhaps you could tell us just what the intended use of the amp is?

> marco



Kind regards

Peter Larsen

--
************************************************** ***********
* \\\\\\\ Quality Ascii handcrafted by Peter Larsen /////// *
* \\\\\\\ My site is at: http://www.muyiovatki.dk /////// *
************************************************** ***********
  #3  
Old December 22nd 03, 07:51 AM
Peter Larsen
external usenet poster
 
Posts: n/a
Default input sensivity / headroom on amplifier

Marco Gaudesi wrote:

> i've a question about the input sensitivity of the amplifier
> electrovoice P3000


> input sensitivity=0dbu (0,775 Vrms)
> maximum input level=+20 dbu (7,75 Vrms)


This appears to mean that with input level control all the way up it
will produce rated power with 0.775 mV input signal and that it with the
input volume control turned all the way down will require 7.75 volts
input signal.

> i have two meter before the amplifier input:
> -Rms Vu meter that display 0dbVU whit a 1 khz sine @ 0 dbu
> (max display=+3dbVU)
> -Peak led meter that display 0db whit a 1 khz sine @ 0 dbu
> (max display=+24db)


Aha.

> i work in live (much peak and not much rms), so i wish to put a
> maximizer/compressor @ L/R, after the maximizer a
> RMS limiter ([email protected] dbu), and after all a peak limiter ([email protected]+19 dbu)....


First tell us what music this is about, if you reinforce natural sound,
then why change it, why not simply reinforce it?

> .... al before the meter (Vu and Peak), so i can keep under
> control in every time the signal that go to the EvP3000, a
> signal where the rms don't go up
> 0dbVu and peak don't go up +19db.


All that matters in terms of clipping is peak level. Most of what
matters in terms of loudspeaker damage is average level. In terms of
hearing damage protection: what works best to prevent hearing damage is
to turn the volume down to sane levels.

> what did you think about this?
> is a correct way to take the full 1200Wrms @4ohm from the Ev3000
> without distorsion, or a stupid way to crash all the system?


*IF* I understood the specs right above - and I am not sure I did - then
you turn the amp all the way down, connect a mixer that conforms to
standard audio levels - most do - to the input and rely on the amps own
internal limiter to prevent it from clipping and keep the sound well
clear of the red range on the meters. But from the description of the
constant gain mode one would generally use this amp in that "constant
gain mode" and with the input signal suitably matched to prevent
clipping. The very point of having so large an amplifier is to avoid
running it near clip-level.

> thank's a lot, and excuse my very bad english.


Your english is fine, but your thinking appears to be unclear and the
aim, the context, of the amps use is undefined. If you need to use
compression or limiting to "get it louder", then you need more sound
equipment anyway, because using compression/limiting to make things
louder without clipping can, not will but can, depending on
circumstances, increase the risk of loudspeaker damage rather than
decrease it.

Perhaps you could tell us just what the intended use of the amp is?

> marco



Kind regards

Peter Larsen

--
************************************************** ***********
* \\\\\\\ Quality Ascii handcrafted by Peter Larsen /////// *
* \\\\\\\ My site is at: http://www.muyiovatki.dk /////// *
************************************************** ***********
  #4  
Old December 22nd 03, 07:51 AM
Peter Larsen
external usenet poster
 
Posts: n/a
Default input sensivity / headroom on amplifier

Marco Gaudesi wrote:

> i've a question about the input sensitivity of the amplifier
> electrovoice P3000


> input sensitivity=0dbu (0,775 Vrms)
> maximum input level=+20 dbu (7,75 Vrms)


This appears to mean that with input level control all the way up it
will produce rated power with 0.775 mV input signal and that it with the
input volume control turned all the way down will require 7.75 volts
input signal.

> i have two meter before the amplifier input:
> -Rms Vu meter that display 0dbVU whit a 1 khz sine @ 0 dbu
> (max display=+3dbVU)
> -Peak led meter that display 0db whit a 1 khz sine @ 0 dbu
> (max display=+24db)


Aha.

> i work in live (much peak and not much rms), so i wish to put a
> maximizer/compressor @ L/R, after the maximizer a
> RMS limiter ([email protected] dbu), and after all a peak limiter ([email protected]+19 dbu)....


First tell us what music this is about, if you reinforce natural sound,
then why change it, why not simply reinforce it?

> .... al before the meter (Vu and Peak), so i can keep under
> control in every time the signal that go to the EvP3000, a
> signal where the rms don't go up
> 0dbVu and peak don't go up +19db.


All that matters in terms of clipping is peak level. Most of what
matters in terms of loudspeaker damage is average level. In terms of
hearing damage protection: what works best to prevent hearing damage is
to turn the volume down to sane levels.

> what did you think about this?
> is a correct way to take the full 1200Wrms @4ohm from the Ev3000
> without distorsion, or a stupid way to crash all the system?


*IF* I understood the specs right above - and I am not sure I did - then
you turn the amp all the way down, connect a mixer that conforms to
standard audio levels - most do - to the input and rely on the amps own
internal limiter to prevent it from clipping and keep the sound well
clear of the red range on the meters. But from the description of the
constant gain mode one would generally use this amp in that "constant
gain mode" and with the input signal suitably matched to prevent
clipping. The very point of having so large an amplifier is to avoid
running it near clip-level.

> thank's a lot, and excuse my very bad english.


Your english is fine, but your thinking appears to be unclear and the
aim, the context, of the amps use is undefined. If you need to use
compression or limiting to "get it louder", then you need more sound
equipment anyway, because using compression/limiting to make things
louder without clipping can, not will but can, depending on
circumstances, increase the risk of loudspeaker damage rather than
decrease it.

Perhaps you could tell us just what the intended use of the amp is?

> marco



Kind regards

Peter Larsen

--
************************************************** ***********
* \\\\\\\ Quality Ascii handcrafted by Peter Larsen /////// *
* \\\\\\\ My site is at: http://www.muyiovatki.dk /////// *
************************************************** ***********
  #5  
Old December 29th 03, 03:32 PM
Richard Kuschel
external usenet poster
 
Posts: n/a
Default input sensivity / headroom on amplifier

>
>hi
>
>i've a question about the input sensitivity of the amplifier electrovoice
>P3000
>
>data sheet EvP3000:
>
>www.electrovoice.com/electrovoice/EVfiles.nsf/lookup/P3000/$File/p3000-eds.p
>df
>( ..../p3000-eds.pdf )
>
>
>input sensitivity=0dbu (0,775 Vrms)
>maximum input level=+20 dbu (7,75 Vrms)
>
>i have two meter before the amplifier input:
>-Rms Vu meter that display 0dbVU whit a 1 khz sine @ 0 dbu
> (max display=+3dbVU)
>-Peak led meter that display 0db whit a 1 khz sine @ 0 dbu
> (max display=+24db)
>
>i work in live (much peak and not much rms), so i wish to put a
>maximizer/compressor @ L/R, after the maximizer a
>RMS limiter ([email protected] dbu), and after all a peak limiter ([email protected]+19 dbu)....
>.... al before the meter (Vu and Peak), so i can keep under control in every
>time the signal that go to the EvP3000, a signal where the rms don't go up
>0dbVu and peak don't go up +19db.
>
>what did you think about this?
>is a correct way to take the full 1200Wrms @4ohm from the Ev3000
>without distorsion, or a stupid way to crash all the system?
>
>thank's a lot, and excuse my very bad english.
>
>marco
>



I was unable to access the page, but this is what your specifications mean.

The amplifier is capable of putting out its rated power with a 0.775 volt
signal (0dBu) You will need to turn down the input attenuation on the of the
power amp if the rest of your system is capable of putting out +19dBu

Very Important!!! This does not adjust the power of the amplifier, only the
amount of voltage necessary to drive the amplifier to full output


The amplifier should be set so that every component in your system clips at the
same time.

In other words, when your preamp input clips, the channel should clip, the
output from your board should clip and the power amp should hit clipping.

Now put in your limiter just before the power amp and set it so that it kicks
in just before the power amp clips, preventing the power amp from clipping.

Turn down input gain on the board just a little bit the board a little bit and
you will be just fine.

If you are looking for more RMS output, set the RMS compressor closer to the
value of the peak limiter. Try +6dbu instead of 0dBu. and make up the gain
reduction from the compresssor with the output level of the compressor.

Richard H. Kuschel
"I canna change the law of physics."-----Scotty
  #6  
Old December 29th 03, 03:32 PM
Richard Kuschel
external usenet poster
 
Posts: n/a
Default input sensivity / headroom on amplifier

>
>hi
>
>i've a question about the input sensitivity of the amplifier electrovoice
>P3000
>
>data sheet EvP3000:
>
>www.electrovoice.com/electrovoice/EVfiles.nsf/lookup/P3000/$File/p3000-eds.p
>df
>( ..../p3000-eds.pdf )
>
>
>input sensitivity=0dbu (0,775 Vrms)
>maximum input level=+20 dbu (7,75 Vrms)
>
>i have two meter before the amplifier input:
>-Rms Vu meter that display 0dbVU whit a 1 khz sine @ 0 dbu
> (max display=+3dbVU)
>-Peak led meter that display 0db whit a 1 khz sine @ 0 dbu
> (max display=+24db)
>
>i work in live (much peak and not much rms), so i wish to put a
>maximizer/compressor @ L/R, after the maximizer a
>RMS limiter ([email protected] dbu), and after all a peak limiter ([email protected]+19 dbu)....
>.... al before the meter (Vu and Peak), so i can keep under control in every
>time the signal that go to the EvP3000, a signal where the rms don't go up
>0dbVu and peak don't go up +19db.
>
>what did you think about this?
>is a correct way to take the full 1200Wrms @4ohm from the Ev3000
>without distorsion, or a stupid way to crash all the system?
>
>thank's a lot, and excuse my very bad english.
>
>marco
>



I was unable to access the page, but this is what your specifications mean.

The amplifier is capable of putting out its rated power with a 0.775 volt
signal (0dBu) You will need to turn down the input attenuation on the of the
power amp if the rest of your system is capable of putting out +19dBu

Very Important!!! This does not adjust the power of the amplifier, only the
amount of voltage necessary to drive the amplifier to full output


The amplifier should be set so that every component in your system clips at the
same time.

In other words, when your preamp input clips, the channel should clip, the
output from your board should clip and the power amp should hit clipping.

Now put in your limiter just before the power amp and set it so that it kicks
in just before the power amp clips, preventing the power amp from clipping.

Turn down input gain on the board just a little bit the board a little bit and
you will be just fine.

If you are looking for more RMS output, set the RMS compressor closer to the
value of the peak limiter. Try +6dbu instead of 0dBu. and make up the gain
reduction from the compresssor with the output level of the compressor.

Richard H. Kuschel
"I canna change the law of physics."-----Scotty
  #7  
Old December 29th 03, 03:32 PM
Richard Kuschel
external usenet poster
 
Posts: n/a
Default input sensivity / headroom on amplifier

>
>hi
>
>i've a question about the input sensitivity of the amplifier electrovoice
>P3000
>
>data sheet EvP3000:
>
>www.electrovoice.com/electrovoice/EVfiles.nsf/lookup/P3000/$File/p3000-eds.p
>df
>( ..../p3000-eds.pdf )
>
>
>input sensitivity=0dbu (0,775 Vrms)
>maximum input level=+20 dbu (7,75 Vrms)
>
>i have two meter before the amplifier input:
>-Rms Vu meter that display 0dbVU whit a 1 khz sine @ 0 dbu
> (max display=+3dbVU)
>-Peak led meter that display 0db whit a 1 khz sine @ 0 dbu
> (max display=+24db)
>
>i work in live (much peak and not much rms), so i wish to put a
>maximizer/compressor @ L/R, after the maximizer a
>RMS limiter ([email protected] dbu), and after all a peak limiter ([email protected]+19 dbu)....
>.... al before the meter (Vu and Peak), so i can keep under control in every
>time the signal that go to the EvP3000, a signal where the rms don't go up
>0dbVu and peak don't go up +19db.
>
>what did you think about this?
>is a correct way to take the full 1200Wrms @4ohm from the Ev3000
>without distorsion, or a stupid way to crash all the system?
>
>thank's a lot, and excuse my very bad english.
>
>marco
>



I was unable to access the page, but this is what your specifications mean.

The amplifier is capable of putting out its rated power with a 0.775 volt
signal (0dBu) You will need to turn down the input attenuation on the of the
power amp if the rest of your system is capable of putting out +19dBu

Very Important!!! This does not adjust the power of the amplifier, only the
amount of voltage necessary to drive the amplifier to full output


The amplifier should be set so that every component in your system clips at the
same time.

In other words, when your preamp input clips, the channel should clip, the
output from your board should clip and the power amp should hit clipping.

Now put in your limiter just before the power amp and set it so that it kicks
in just before the power amp clips, preventing the power amp from clipping.

Turn down input gain on the board just a little bit the board a little bit and
you will be just fine.

If you are looking for more RMS output, set the RMS compressor closer to the
value of the peak limiter. Try +6dbu instead of 0dBu. and make up the gain
reduction from the compresssor with the output level of the compressor.

Richard H. Kuschel
"I canna change the law of physics."-----Scotty
 




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