HOLMImpulse: Measuring Frequency- & Impulse-Response

[Moondog55]

Just checked the download page, what a shame i am still using W2000 Pro; due to now wanting to make Mr gates any richer than I have too, not to mention multiple license issues not transferring to the upgrade

[gedlee]

Originally posted by askbojesen
(Sent me a direct message if of any interest)

The site says that you don't accept E-mails. You can Email me at egeddes@gedlee.com

Thanks

[Salas]

On what assembly have you measured the Panasonic capsules? Were they inset on the end of some tube? They normally gain 4dB up to 20kHz if there is a lip around their edge due to diffraction.

[soongsc]

Originally posted by askbojesen


Your soundcard is out of phase with itself. Check of the "Invert recorded signal" under device settings. At the impulse response it is very clear that the impulse is going down instead of up.

Originally posted by Dr.EM
Ah yes, that's much better! Thought the phase was a bit odd

Is there a way to compensate for interchannel latency? I could not find it in the various screen captures on the web site. This would be much needed if people are going to be using lower cost sound cards.

[askbojesen]

Originally posted by Moondog55
Just checked the download page, what a shame i am still using W2000 Pro; due to now wanting to make Mr gates any richer than I have too, not to mention multiple license issues not transferring to the upgrade

Hi, I just changed the text to: Windows (2000, XP & Vista)
There is no reason that it should not work on w2000, I did not know anybody was using that in 2009

[askbojesen]

Originally posted by soongsc
Is there a way to compensate for interchannel latency? I could not find it in the various screen captures on the web site. This would be much needed if people are going to be using lower cost sound cards.

Latency is no problem - I filter away the latency - I can deal with an arbitrary large latency, lets say up to e.g. 1000 ms. HOLMImpulse auto detects the received impulse-peak.

[askbojesen]

Originally posted by Salas
On what assembly have you measured the Panasonic capsules? Were they inset on the end of some tube? They normally gain 4dB up to 20kHz if there is a lip around their edge due to diffraction.

Attached picture shows the mounting in an alu-tube (Stuffed with damping materiel)

as I seen in

http://www.diyaudio.com/forums/showt...07#post1841507

I also get 4-5dB gain at 20kHz (The base level at the graphs is at -4dB) , but it drops again at 20kHz and upwards

[soongsc]

Originally posted by askbojesen


Latency is no problem - I filter away the latency - I can deal with an arbitrary large latency, lets say up to e.g. 1000 ms. HOLMImpulse auto detects the received impulse-peak.

I think the best way would be to just run a test to find out whether it's a problem or not. I have the right card to test this.

[Moondog55]

Hi, I just changed the text to: Windows (2000, XP & Vista) There is no reason that it should not work on w2000, I did not know anybody was using that in 2009

Thank you,

Blame poverty; spending all of my money on drivers not operating systems, and it actually has no disadvantage except I can't play any of the new games, which saves me more money

[Salas]

Originally posted by askbojesen


Attached picture shows the mounting in an alu-tube (Stuffed with damping materiel)

as I seen in

http://www.diyaudio.com/forums/showt...07#post1841507

I also get 4-5dB gain at 20kHz (The base level at the graphs is at -4dB) , but it drops again at 20kHz and upwards

Totally normal. I just wanted to compare some ballpark data for 20k to 40k, and your construction follows one or two of my mics.
If the capsule is made to protrude, the diffraction is roughly half, so its the rise, maybe better for high frequency impulse measurement. But if it drops on the floor, its history. See pic. On the left protruding, on the right inset.