A Windows 7 Measurement Rig

Langston Holland

Langston Holland

Sophomore
Jan 13, 2011
222
0
16
Pensacola
This is kind of a brag about the Windows 7 32 bit OS on my new MacBook Pro 17" (2.8Ghz processor, 8GB RAM). It's such a huge upgrade from the copy of XP I had been using that it's tamed my longing for native OSX audio software. With the new audio driver scheme I'm able to do stuff that only OSX used to be happy with, such as running multiple audio applications sharing I/O interfaces at will while requiring less than 50% CPU utilization. Smaart v5.4 used to hog the majority of CPU cycles running by itself in XP on the same processor.

The attached screenshot shows the following occurring simultaneously:

1. ARTA v1.7 generating a 32 bit 48kHz periodic (synchronous) pink noise stimulus through a Duran D-Audio USB sound device with both channels in loopback mode.

2. Adobe Audition 3 recording both channels of the D-Audio's inputs. I record my measurement sessions in case I want to go back and change EQ, crossovers or driver/sub alignments afterwards. Thus I don't have to go to the trouble of making the measurement again - and in some cases I don't even have access to the loudspeakers anymore. I record temperature and humidity as well to compensate for changes in the speed of sound re: alignments and phase tuning.

3. Both ARTA and Smaart v5.4 performing real time dual channel 32k FFT's with averaging at full speed.

4. All network drivers are online without DPC latency issues.

Did I mention I was impressed with Win 7? :)
 

Attachments

  • Win 7 Running Everything.png
    Win 7 Running Everything.png
    598.6 KB · Views: 0
Re: A Windows 7 Measurement Rig

I own v7 - I'll buy anything Jamie and Calvert ever get involved with. But... v7 doesn't yet sport (as far as I know) a feature I need and use constantly - subtracting an inverted reference trace from a live trace.
 
Re: A Windows 7 Measurement Rig

Hey Langston,
couldn't you do an inverse curve, save it as a weighting curve and use that?
still not as cool as the subtract function though :)
edit: I put a request in......
 
Re: A Windows 7 Measurement Rig

Langston Holland said:
snip-

2. Adobe Audition 3 recording both channels of the D-Audio's inputs. I record my measurement sessions in case I want to go back and change EQ, crossovers or driver/sub alignments afterwards. Thus I don't have to go to the trouble of making the measurement again - and in some cases I don't even have access to the loudspeakers anymore. I record temperature and humidity as well to compensate for changes in the speed of sound re: alignments and phase tuning.
Click to expand...


I suggest that when you save the measurement you save it as an Impulse Response if possible.
Allows you to set different gate points before running an FFT.
I do not know if Smaart or ARTA will do this post process. ARTA might.





Langston Holland said:
Did I mention I was impressed with Win 7? :)
Click to expand...

I have found win7 faster then VISTA and more "Bug Free".
The interesting part is I have had huge problems with audio on the newer OS. winXp has mostly worked. VISTA has been horrible. Make it twice as bad if you use a laptop vs. desktop.
Anything that is part of Blue Tooth just kills a Pro level soundcard. (RME, MOTU).
I finally went to dual boot so I have a winXP OS available that is stripped to the bone.

Researching this if you have a studio they suggest you use win2000! Less garbage, less latency issues.

That said going through Apple OS seems to have made you immune. Of course none of my programs will run on Apple OS.
 
Re: A Windows 7 Measurement Rig

Too Tall said:
I suggest that when you save the measurement you save it as an Impulse Response if possible.
Allows you to set different gate points before running an FFT.
I do not know if Smaart or ARTA will do this post process. ARTA might.
Click to expand...

Good point as always. :)

Ultimately, the IR has everything in it that disturbed the equilibrium of the atmospheric pressure around the measurement mic capsule. Not that we can correlate everything we hear with that perturbation at this point, but we have come a long way toward that goal. ARTA is fluent with the IR and can acquire it via internal or external stimuli as well as file import. A very cool additional feature is that its real time module can export a transfer function measurement into an IR for analysis simply by clicking on the IR module icon while making (or pausing) the real time measurement. Nothing ground breaking here, FFT and its inverse, but ARTA makes it extremely convenient.

My decision to catalog 10 sec two channel wave files of the actual measurements has several advantages over just recording a snapshot of the IR:

1. I can loop this recording through a loudspeaker processor to make adjustments as if I were actually doing the measurement. Looping an IR pulse through a loudspeaker processor does not mimic what occurs in the real world even if you could get it to work.

2. I'm able to confidence monitor the magnitude and phase traces with Smaart and ARTA during the recording to make sure I get a good 10 sec's of data. This sometimes involves recording more than 10 sec's and using a wave editor to delete the data when the wind messed with the phase trace. :)

3. I can loop the measurement recording through ARTA and pause it at any time I feel best to derive the IR from an inverse FFT of same - by clicking on a button! What a cool time to be alive. :)

Researching this if you have a studio they suggest you use win2000! Less garbage, less latency issues.
Click to expand...

I wish! I loved Win2k with audio stuff in the day, but the problem is that within my new laptop's lifespan there will be audio software I'll want that won't work without Win7. I'm just happily surprised with how well Win7 handles audio I/O for a non-realtime OS, thus I can focus on what I'm doing instead of how to make the dumb computer work - like OSX (for the most part).
 
Re: A Windows 7 Measurement Rig

Glad to see that someone worked out the Virtual PC thing. I bought a copy of VirtualPC and it trashed the bios on my Powerbook. I was luckily able to roll with demo version of v6 until it became available for Mac. I'm enjoying v7 but feel your pain. I still keep a copy of v6 on my new MacBook Pro for certain applications.
 
Re: A Windows 7 Measurement Rig

Hey Kip!

Great to hear from you. :) v7 has the right infrastructure and appears to be progressing nicely toward the head of the class again in real time measurement. Virtual machines within OSX still can't reliably deal with external audio I/O - thus I use Boot Camp. The MacBook Pro makes the best Windows platform I've ever used and boot times with current hardware and OS's is minimal, so I'm happy.
 
Re: A Windows 7 Measurement Rig

Pascal.Pincosy said:
Hey Too Tall,
How well does Praxis run under Windows 7?
Click to expand...

The program itself runs great on it. I have had some issues figuring out the win7 mixer.

Back when we had windows3.1 or perhaps the next OS there has been a file named snd32 or something like that.
"The Windows Mixer" was on every OS till VISTA.

One of the prominent features of Praxis was that it could measure absolute SPL, not just relative.
It had an outboard interface through which all input and output went through feeding the soundcard.

After the program was installed you went through a calibration run which gave you the best dynamic range and signal to noise your soundcard could produce. It memorized the mixer settings playback and record and it was ready to make absolute measurements as soon as you had a calibrated mic.

This was not the typical one of two frequencies. It came up with a deviation file at about 300 points for both frequency response magnitude and phase.
Note: Kin Giarden makes the calibrated microphones you can buy along with Praxis.
You can send him your mic and he will calibrate it for an inexpensive price.

Anyway with MS changing the mixer you now have to write down the number and set the mixer control by hand every time you boot the program or at least look at the fader.
The way win7 works, every time you open any program that has audio going through it (FireFox?) it gives you another slider for that “source”.
Often the Praxis fader is still set at the same place you wrote down during calibration unless you changed it for some reason.
Sometimes it screws up, sometimes I screw up.
Sometimes it will not make a fader for Praxis when I boot the program. I have to make a measurement and then it will show the Praxis fader.

NOTE: With the new security protocols windows does not like you to put anything in the Programs/Praxis root folder. It does not like to see anything change there.
So when you install Praxis you have the Praxis in the root files and another Praxis folder in users/public where Windows does not care if the contents change.
Do NOT Fight this!
I think I screwed up trying to fight that.

In the end I have winXP as dual boot on all my computers for Praxis and LspCADv6 Pro

I had some trouble with Praxis or Yahoo Messenger finding the record mixer. Win7 did an update and it went away.
 
Top Bottom