Chris Ilett wrote on Mon, 20 April 2009 06:27 |
Phillip Graham wrote on Fri, 17 April 2009 20:33 |
bblackwood wrote on Fri, 17 April 2009 21:03 | Getting 100-300 Hz right is really difficult but truly seems to separate the 'men from the boys'...
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And for us in the live sound world the most important range for getting the PA system to integrate properly with the room...
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Depending on the room
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Hey Chris,
What I meant by my statement is that not only is this frequency range important for the mix, but that the rooms' role with the speaker system influences it, too.
Most small professional speaker systems have a high degree of directivity (ie directional control of where the sound goes) above 2kHz, but below this point the wavelengths get large and spill around the sides/back of the box.
Just as your studio monitors interact differently in the recording space depending on whether they are near/far from the wall, the same is true with PA systems.
Unlike most studio settings where people seem adverse to speaker equalization, we use it as a powerful tool to smooth and shape the speaker/room combination through the mids and midbass. Often times the speaker location is dictated by factors of asthetics and is sub-optimal acoustically, so we utilize every tool we can get.
Using one of the major pro-sound analysis products, one can look at the phase behavior in the Nyquist plot of the system and ascertain if the response error is attributed to the loudspeaker system, or not. Since loudspeaker acoustical response is, in general, minimum phase, one can calculate the Hilbert transform of the magnitude response and see if the resulting calculated phase behavior matches the measured behavior.
If the measured phase is not minimum phase in nature, then it is generally time to start looking for acoustic treatment solutions, if the situation is amenable to this...
The only name I know of in the studio world who specifically does this kind of work is Bob Hodas.
Last fall, during and after his session on small space acoustics I had a lively discussion with John Storyck about WSDG's use of similar measurement techniques and equalization.
If you are an AES member, and listen to John's talk from AES 109 in San Fran, I am the fellow asking pointed questions throughout his talk