HOLMImpulse: Measurements in practice

Hi guys. I have a question. Am i doing something wrong if my measurements look like this ?

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


They are all rippled and impulse looks odd to me. I can't see when room reflection starts because impulse is all but good.

I dunno. I'm probably doing something wrong :(

Distance between mic and speaker is 1m. I removed everything arround it and stacked pillows on the floor to minimize reflections. Gated properly (around 3ms for 1m distance) and still it doesn't loook right to me.

This is midbass in the BR cabinet with no xover.
 
Last edited:
Behringer ECM8000 mic
M-audio fast track USB soundcard with phantom power
Desktop computer

Pano mentioned, on page before this, that i don't need to do loop back calibration for M-audio sound card because it is very flat. I was going to do it but i just coudn't wait to try it.

Is it possible that this is due no loopback calibration ?

I'm using WIN7 on my desktop.

Thanks John.
 
I'm not sure exactly what you just tested, but if you did not do the loop measurement I suggested (not calibration - just take a measurement), then you did not really eliminate much. Do the loop measurement. If it is bad, look for a setting to prevent the input to the soundcard from getting fed back to the output. For some reason this seems to be the default on a lot of systems. If you have windows, a lot of times it's a simple as opening the sound mixer and muting the line in.
 
I disabled onboard sound card in BIOS and uninstaled drivers for it.

Sound mixer is opening only properties for M-audio now.

I'll do the loop measurement tomorrow. Stores are closed now and i have to make cable for loop measuring first (XLR to RCA).
 
Last edited:
Just another Moderator
Joined 2003
Paid Member
I'd second the loopback measurement. Audigy cards have a "record without monitoring" option which if you don't use it you get odd results, the M-Audio may have something similar. first step is getting a flat line with the loopback. Also you might want to high pass the signal at say 200 or 200 Hz.

Tony.
 
It is off now and it looks like this:

2qvbhj7.jpg
 
Administrator
Joined 2004
Paid Member
Do you have an RCA to 1/4" (6.35mm) cable or adapter? If so, then connect the output to the 1/4" input. Be sure that HOLM is set to output to both channels. Test that. At least that way you are going unbalanced to unbalanced.

Turn on the VU record meters in HOLM to see what input levels you are getting.