HOLMImpulse: Measuring Frequency & Impulse Response

Re: documentation

aduljr said:
How about a community wiki for the documentation? Let us help contribute to it as well. :)


How about a HOLM for Dummies? (Me, I feel dummer by the day on this site!!).

I do not want to bog down this thread with really silly and probably easy to answer questions, could we create a HOLM for dummies thread?
 
HOLMImpulse in practice - New thread ?

doug20 said:
How about a HOLM for Dummies? (Me, I feel dummer by the day on this site!!).
I do not want to bog down this thread with really silly and probably easy to answer questions, could we create a HOLM for dummies thread?

You are most welcome to start this new thread, I suggest you call it
"HOLMImpulse in practice" ?? (You might offend somebodies mind...)
I'll be happy to answer questions in that thread also.

But I think that gedlee is right, lets keep this thread alive, so it would be nice to see some responses with responses ;)

If you are not able to get a proper response, or nothing at all, then show what you have got anyway! - I might have some tricks.

Or Bugfixes or features or...
 
I have a small bug with the installer.
When done the dialog just sits as 90% indefinitely until I change focus to another app at which point it goes to 100% with the close button enabled.
Looks like it does not detect when the installer is done (closed).

Nothing major just thought you might want to know.
No info that I can think of to help you nail it down.
 
Here are some measurement I made with an older version about a year ago (opened with the latest version to take screenshot)
The drives B&C 15PE40 where hung free about 1.8m up in the air. The mic was placed 1m in front of it. The mic was a XTZ room analyzer (does anyone have a cal file for this mic?)
The room looks like it creates some nasty artifacts. 7.5m x 3.9m x 2.3m concrete with windows on the right wall.

The consistency if the drives looks impressive considering they where used when I bought them. Think they came from a theater but I'm not sure.

An externally hosted image should be here but it was not working when we last tested it.


Any comments?
 
David_Web said:
Any comments?

http://img8.imageshack.us/img8/2861/boc15pe40holm.png

The image server is very slow 1.6 KB/sec .... :snail: :snail: :snail:
Maybe a comment tomorrow, when the image has been downloaded :D

Ohh now the image came...

  • The Impulse is inverted - Try "Invert recorded signal" under device settings or the "Invert Amplitude" button under "Options" for each measurement
  • What about the timewindow? Also under the options menu for each measurement - try the autodetect (This is done automatically when you measure)
  • If you want the total response the choose a smoothing 1/N Octave filter (Also under options)
 

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Running on an old HP laptop - WinXP. M-Audio USB Duo as sound card.

Everything seems to work just fine. Software even told me the input was clipping during calibration. Turned it down a bit, got a good file.

All seems to work well - all 3 methods give same results (sweep, chirp, MLS).

OK, So now what do I do with it? :smash:
 
Re: HOLMImpulse in practice - New thread ?

askbojesen said:


You are most welcome to start this new thread, I suggest you call it
"HOLMImpulse in practice" ?? (You might offend somebodies mind...)
I'll be happy to answer questions in that thread also.

But I think that gedlee is right, lets keep this thread alive, so it would be nice to see some responses with responses ;)

If you are not able to get a proper response, or nothing at all, then show what you have got anyway! - I might have some tricks.

Or Bugfixes or features or...


Thats cool, I can keep it here. I have it running but I didnt get to far with the soundcard measurements. It just didnt look right so I went back to using REW and ARTA for quick measurements of my new speakers.

I will spend sometime this weekend getting screen shots and questions ready.
 
64 bit

gedlee said:
The software installs OK under Vista - 64 bit and it opens. But it doesn't recognize the sound card and it crashes whenever any sound card features are attempted, like trying to select the sound card.

Sorry to hear this, I must install a 64 bit Vista and test for my self.

(The audio library is portaudio which can work in 64 bit, so there is hope...)

I'll let you know when I have figured this out :scratch:
 
Loaded it on my XP-Pro machine, no problems. But a loopback measurement didn't look good and it was very difficult to figure out the problem.

I would suggest a window that shows the input and output time signals. Thats a big help in sorting out errors. And rather than use the generated signal directly, I would let the user select where to pick up this signal (i.e. a two channel input where one channel is what you do now and the other channel is the input signal picked up where it makes the most sense). This adds a great deal more flexibility in the usage of the system. This later aspect could be an option.
 
Just installed HOLMImpulse and did a loopback test using Audigy 2ZS notebook soundcard. Things look good. There is no interchannel latency related issues. But now it seems besides a mic calibration, soundcard calibration might also be necessary as well. Probably the best way to do this is summing the mic and electronics curves to for a new calibration curve?
 
Sure, calibration would include mic calibration, mic preamp (if nor originally included), and the soundcard. Although the SC and mic preamp would seem flat amplitude wise, the phase deviation accumulates pretty quickly. I am assuming the phase is measured instead of derived from the amplitude.
 
Hello,

Very nice tool, thanks.
It seem stable, practical and simple.

I agree with gedlee, a monitor of the levels send & return will be useful even more if we could have a test tone.
Also a csd waterwal will help a lot as said ThomasHolm.


Thanks again for your work.
 
Ask is away visiting family over the weekend..

Soongsc + panomaniac: Try running a "Make" DAC-ADC calibration with a loopback input to output shorted. This should solve your soundcard gain + phase problem and not interfere with the Mic calibration. If the uncalibrated loopback is severely off (More than 1-2dB amplitude deviation 20Hz to 20kHz) i would personally not use that card..