[linux-audio-dev] live pa questions

Pieter Palmers pieterp at joow.be
Mon Apr 4 18:38:36 UTC 2005


Paul Winkler wrote:

>On Mon, Apr 04, 2005 at 05:55:12PM +0100, Dave Griffiths wrote:
>  
>
>>On Mon, 04 Apr 2005 18:01:02 +0200, Pieter Palmers wrote
>>    
>>
>>>the following links provide quite some info regarding distortion, 
>>>clipping and DC offsets:
>>>http://sound.westhost.com/clipping.htm
>>>http://sound.westhost.com/tweeters.htm
>>>      
>>>
>>interesting articles
>> 
>>    
>>
>>>My recommendations:
>>>- Be sure to do a decent sound-check: have a full-scale piece of 
>>>music ready for the PA engineer to set the PA desk incoming level, 
>>>and be sure not to change your volume when soundcheck is done. - 
>>>Adapt the dynamic range of your music to the live enviroment, e.g. 
>>>by using a compressor plugin just before the soundcard output.
>>>      
>>>
>>so it isn't so much of a software problem, but rather the responsibility of
>>the artist to keep the dynamic range down, and the sound engineer to set the
>>levels sensibly?
>>
>>it's interesting though, as a lot of performers who use computers eschew the
>>soundcheck these days, thinking just a line test, or just plugging in and
>>setting the volume, is enough. 
>>
>>so, would it be a good idea to purchase a small compressor, if using homemade
>>analogue synths, or even software capable of producing nasty signals?
>>    
>>
>
>A compressor might not be fast or hard enough to buy you much safety.
>For that, better would be a good fast limiter and a subsonic filter.
>The filter is pretty easy and cheap (see e.g. the Harrison Labs Fmod),
>but I don't happen to know of a really good inexpensive brick-wall
>limiter first-hand.  I've heard that the Aphex Dominator isn't bad, but
>it's hardly cheap.  Maybe one of the DBX models?  *shrug* 
>
>  
>
Behringer offers an active crossover with limiters on each band + 
subsonic filter (CX3400), at a very nice price (€150).
The only drawback is that it isn't a real brickwall limiter, the system 
behind this limiter still has to be able to cope with signals that are 
+6dB higher than the 'limit'.

>If I owned a venue or rented a sound system I'd probably provide my own
>anyway, but I don't know how many do that.
>
>  
>
All PA companies I've worked with have limiters installed, especially 
the rental companies. Most of the time they are installed in the same 
flightcase as the amps, and sometimes they are integrated into a 
'speaker management' device.

Pieter





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