1 Topic by jeffspc88mx (edited by jeffspc88mx 2011-03-18 03:27:50)

  • Registered: 2011-03-14
  • Posts: 3

Topic: AIO doesn't play with Room EQ Wizard software?

I'm using a freeware program called Room EQ Wizard (REW)(java based) to examine the effect of my acoustic treatment. The first step is to externally "loopback" the soundcard's output directly its input and examine the frequency response of the soundcard itself by feeding a 0dB sinewave sweep through the card and measuring the output. This is what I'm now attempting with the AIO card (PCIe) in my Mac Pro (OS 10.6.x). Unfortunately I get hideous results. What should be a nice flat line between 20-20000 Hz is instead a snaking morass of comb filtering spanning ~40dB.

I don't think it's an internal feedback thing because if I use my microphone, I can see the input levels fluctuate, but not the output ones. I've tried just plugging the AIO's analog ins directly to its outs as well as using my mixer to send the outputs back to the inputs - same result (so it's not my mixer). Also, if I use my built-in sound hardware (the Mac Pro's own internal sound I/O), I get good results, so it's specific to the AIO card.

The Apple MIDI Setup program indicates the the AIO I/O is at 48KHz/32 bit. This is the correct rate for the Room EQ Wizard, but I don't think it can handle 32-bit directly. Might this be a problem? I'm aware that other folks have used HDSPe hardware effectively, so I'm hoping this is just me being a novice smile



http://img651.imageshack.us/img651/8809/rewdoesntwork.png

  • Registered: 2011-03-14
  • Posts: 3

Re: AIO doesn't play with Room EQ Wizard software?

After monitoring the pulse and sine wave sweep that the software generates, I've determined that there is a significant delay (~0.7-1.0 s) between when the software sends a sound and when it's actually output through the card. It also seems that, absent a signal, the card is ignoring the initial signal from the software. This explains why the software is not "happy" with the results, but I'd still like to know why my $900 card can't handle it (it handle's other stuff (Cubase, iTunes) just fine.

Did I mention that this software is Java based? I know that OS 10 (Mac) doesn't have the best Java audio implementation.

  • Registered: 2012-04-09
  • Posts: 4

Re: AIO doesn't play with Room EQ Wizard software?

I really would like to know too.

That software (free, optional donations) can create a signal for calculating, and AIO pick that signal up.
But I still can't hear the EQ changes I made in that software.

And I recognize similar test results from that software.
Best / Fredrik