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#2559456 - 01/08/14 08:47 AM sweep tone as audio signal test.
alidav Offline
Member

Registered: 03/31/08
Posts: 14
Loc: italy
what are the signal audio test requested to make a good deep and pratical audio measurement to make improvement?
IN live sound reinforcement we have been using pink noise signal, why some software as fuzz measure uses only the sweep tone?
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david aliperti

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#2559522 - 01/08/14 12:29 PM Re: sweep tone as audio signal test. [Re: alidav]
Ethan Winer Moderator Offline
MP Hall of Fame Member

Registered: 06/12/00
Posts: 8905
Loc: New Milford, CT, USA
The acoustic metrics for large venues and small rooms are very different. The main concern in a large space is reverb time (RT60) in each of the third-octave bands. In small rooms reverb has less meaning, so the concerns are mainly peaks and nulls and ringing at low frequencies, and the strength of "early" reflections. Pink noise is fine for measuring RT60 in a venue, but a swept sine wave is much more versatile in small rooms. The good news is you don't need to create your own sine waves. Room measuring software does this automatically as explained here:

Room Measuring Primer

--Ethan

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#2559950 - 01/09/14 06:15 PM Re: sweep tone as audio signal test. [Re: Ethan Winer]
audioskeptic Offline
Member

Registered: 01/09/14
Posts: 3
You could also use the method described in http://www.aes.org/sections/pnw/pnwrecaps/2012/jj_jan/ if you bother to load some freeware on your laptop (assuming you have a mike) and you can get the impulse response of the room, which you can then do anything you want with.

It might help to put up the ppt file and listen to the talk first. Then you will know more than you wanted to.

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#2567903 - 01/31/14 03:30 PM Re: sweep tone as audio signal test. [Re: audioskeptic]
alidav Offline
Member

Registered: 03/31/08
Posts: 14
Loc: italy
what kind of approach would you do in a 150 meters square, with all concrete and very hard surfaces, the goal is just to give som acoustic confort since, what di I need to evaluate first, the rt 60 ? resonances frequencies
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david aliperti

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#2568156 - 02/01/14 10:49 AM Re: sweep tone as audio signal test. [Re: alidav]
Ethan Winer Moderator Offline
MP Hall of Fame Member

Registered: 06/12/00
Posts: 8905
Loc: New Milford, CT, USA
The main problem in a very large space like a gymnasium or auditorium is excess reverb. So for that you'll display RT60 by frequency as in this graph from the article above. But 150 square meters is not huge, so you should also view the response and low frequency ringing.

--Ethan


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#2753200 - 02/06/16 05:32 AM Re: sweep tone as audio signal test. [Re: Ethan Winer]
alidav Offline
Member

Registered: 03/31/08
Posts: 14
Loc: italy
we are setting now the alignment of components (loudspeaker cabinets) and crossover for a PA SOUND REINFORCEMENT system, i found so easy and immediate using the sweep tone, why everyone still is using the pink noise signal?
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david aliperti

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#2775270 - 04/26/16 02:02 PM Re: sweep tone as audio signal test. [Re: alidav]
Arnold B. Kruege Offline
Senior Member

Registered: 05/07/14
Posts: 40
Originally Posted By: alidav
we are setting now the alignment of components (loudspeaker cabinets) and crossover for a PA SOUND REINFORCEMENT system, i found so easy and immediate using the sweep tone, why everyone still is using the pink noise signal?


Good question. The better room/speaker measurement programs are often based on analyzing a swept tone with a tracking filter. Example: Holme Impulse (Freeware). I think REW goes that route as well.

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Moderator:  Ethan Winer