HOLMImpulse: Measuring Frequency- & Impulse-Response

[askbojesen]

Reverberation button:

1. Shows the Impulse Response in dB
2. Zooms out so that the reverberation can be seen

(Does not change the measurement only the prensentation)

[gedlee]

Ask

Also, please don't loose my request to see the actual source and receive time signals as this is very valuable information when debugging a setup (you never mentioned this).

I had trouble with level issues as one other poster commented, but it took a while to track this down. If I could have seen the signals being used then I would have known immediately what the problem was. I simply do not trust any measurement where I can't see the raw data being used.

The program does look like a very good start - it could be great.

[John Sheerin]

Hey Earl,
How did you resolve your level issues? My issue as previously posted is that I can't get a loud enough output from the program. Is there a setting somewhere in there that I'm missing? Another program drives me out of the room at the level I have my Windows mixer set to. I can hear the sweep, just very faintly.

John

[Pano]

Originally posted by KSTR
I'm using ASIO-drivers under XP

Really? I could not get it to work with the ASIO driver for my M-Audio card. The MME-USB worked fine, tho. The ASIO just never showed as a choice. (Works OK with other software)

[askbojesen]

Now HOLMImpulse does not have ASIO support - only MME

The audio library (PortAudio) can support ASIO, but I see no need for that yet. (The increased latency in MME is no problem for such an application)

ASIO
- Do you have soundcards, that have ASIO, but not MME?
- How much do you prioritize ASIO support?

Levels
The logsweep send via MME has full level and HOLMImpulse does not do anything for the MME volume settings. In XP the master and wave volume must be adjusted. In Vista the application level and recording level.

Audacity
Audacity also uses PortAudio with MME-support.
In Audacity you can see the out->in waveforms, so until HOLMImpulse shows the out->in waveform, you can use this application for troubleshooting the MME sound-levels.
(In audacity you can generate waveforms)

[askbojesen]

Originally posted by gedlee
Also, please don't loose my request to see the actual source and receive time signals as this is very valuable information when debugging a setup (you never mentioned this).

Maybe you are right, but showing the Waveforms is not a simple task

• How to integrate in GUI
• Performance, Performance, don't slow measuring down
• Performance, zooming, latency, ...

I have to think...
Thanks for the feedback
Don't misunderstand me... you do like to

NB: I if you haven't smilies enabled above does not make sense.

[KSTR]

My card driver supports both ASIO and MME, and it's control panel has an explicit button to enable MME, which is off, by default. For some reason they seem to be enabled anyway, it seems. Other apps offer ASIO Control panels which seem to work.

- Klaus

[KSTR]

And Ask,

pls don't forget a DUT response IMPORT option, for offline-processing and "raw" use of the convolver, since I intend to preprocess the DUT response if needed (you can see, I just want to abuse your programming skills to get around programming my own freq-domain convolver with partitioning and all the frills needed to make it run efficiently, ha-ha).

And take your time, no need to hurry.

- Klaus

[KSTR]

>> For some reason they [MME] seem to be enabled anyway, it seems.

Counterchecked with Samplitude. when I turn MME off, they also disappear from the device list. Something is funny, then... but never mind...

[soongsc]

I wonder whether wavelett transform could be of any use or not. Most techinques sort of lump the results in a spectrum and lose the time associated with a particular stimulus response.