View Full Version : Q: Making of an impulse response

10-22-2002, 04:18 AM

I am interested in knowing just exactly how the impulse response that came with GOS was made? In particular, the equipment used?

The acoustic laboratory in my engineering school is currently setting up a data acquisition laptop to be used to capture sound/noise. They are thinking of using a laptop for portability and the software is DIRAC from Bruel and Kjaer. The requirements of the DIRAC software is that any full-duplex soundcard would be fine. Seeing as the field measurements are to be done in 96kHz, the only model I can think of is the MOTU896 firewire model. The M-Audio USB (Duo/Quotro) models only allow either 2in OR 2out at 96kHz but we are thinking that somewhere in the future we may need to have the ins and outs happening at the same time.

Anybody got any idea on what I should recommend?


10-22-2002, 04:08 PM
Hi Maestro Meeehoon,

The GOS impulses used a proprietary process.
The impulses were recorded with various types of microphones. We used many different source sounds for the test tone or impulse. The test tones were made at various positions on the stage. We wanted to catch as many of the frequencies and as many positions as possible.
A special proprietary software was used to process these signals.

For commercially available processes, look at Altiverb or Acoustic Mirror. In addition to a high sampling rate, I would also recommend the highest bit rate possible. I\'m not familair with DIRAC from Bruel and Kjaer, but their microphones are excellent. I see no reason why a laptop will not work. Of course, firewire will offer greater thoughput than USB 1.1. Also take a look at PCMCIA solutions - such as the RME and Digigram products as well as the Echo Audio Layla LapTop and Mon LapTop. You will need simulataneous ins and outs if you\'re playing sweep tones at the same time you are recording the response. Hope this helps.

Gary Garritan