A HOLM starter guide

[ernperkins]

Re: A HOLM starter guide

Check out the very end of the PCD part of the tutorial where I explain that. Thanks for pointing it out.

Oops, missed that while I was scrolling through the pages. It is there...

[ryanbouma]

Re: A HOLM starter guide

I haven't dived into all of the technical details yet, but -- it might be easier to use Response Modeler to adjust the overall SPL of an FRD once you've created it?

I haven't used RM, other than to extract min phase. If that's doable, sounds like a good way to do it. I'm not sure RM will accept a negative value though, so some offsetting (+40db or so) may still be required.

Thanks for pointing that out.

[donradick]

Re: A HOLM starter guide

Very, very nice. Lots of help for critical, but seldom documented checkboxes that may turn out to be important. Appreciate all the extra screenshots and annotation. good work!

[ryanbouma]

Re: A HOLM starter guide

Can HolmImpulse accept an .frd file for mic calibration? I know it takes a .txt simply enough. Anyone know about this? Thanks.

[killa]

Re: A HOLM starter guide

Can HolmImpulse accept an .frd file for mic calibration? I know it takes a .txt simply enough. Anyone know about this? Thanks.

Couldn't you just turn the frd into a txt file?

[Zvuchniak]

Re: A HOLM starter guide

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



They are all rippled and impulse looks odd. 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. This is midbass in the BR cabinet with no xover.

Measuring equipment is Behringer ECM8000 mic, M-audio fast track USB soundcard with phantom power, Win7 Desktop computer. I remeasured it with my notebook just in case and it looks the same. I disabled onboard sound card in BIOS and uninstaled drivers for it.

If this is off i'll be thankful if mods would move it

[killa]

Re: A HOLM starter guide

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

[ATTACH=CONFIG]27177[/ATTACH]

They are all rippled and impulse looks odd. 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. This is midbass in the BR cabinet with no xover.

Measuring equipment is Behringer ECM8000 mic, M-audio fast track USB soundcard with phantom power, Win7 Desktop computer. I remeasured it with my notebook just in case and it looks the same. I disabled onboard sound card in BIOS and uninstaled drivers for it.

If this is off i'll be thankful if mods would move it

I think you are gated too low. Can we get a pic that isn't zoomed in on the gating as much?

[Zvuchniak]

Re: A HOLM starter guide

I think you are gated too low. Can we get a pic that isn't zoomed in on the gating as much?

I gated on 3ms. That is proper gating for 1m (40") distance.

Impulse looks bad and i can't see first reflection regardless of gating (which is good in my oppinion).

[Zvuchniak]

Re: A HOLM starter guide

Here's the pic:

[killa]

Re: A HOLM starter guide

I gated on 3ms. That is proper gating for 1m (40") distance.

Impulse looks bad and i can't see first reflection regardless of gating (which is good in my oppinion).

Your gating can not be set properly if you can't see the first reflection. The first reflection is what tells you where to set the gate.

[Zvuchniak]

Re: A HOLM starter guide

Your gating can not be set properly if you can't see the first reflection. The first reflection is what tells you where to set the gate.

The distance between the speaker and mic is what tells you where to set the time gate. Impulse response just helps you visualise that. Gating can be set properly if you know what is the distance between mic and speakers and if there are no near objects that the sound can be reflected of.

My question is if anyone can tell me why my impulse response looks that way that it looks ?

[JasonP]

Re: A HOLM starter guide

Maybe I am off-base, but just thinking out-loud are you sure you are getting a clean measurement from your mic? I'd look at the max. PCM level (should be on the bottom left of the holm impulse test page) and see if its a nice negative value. My best measurements seem to happen when that reads -2 to -5 db.

[killa]

Re: A HOLM starter guide

That is wrong and could possibly be why your having problems. It is very hard for me to gate that low indoors due to ceiling and floor reflections.
See post #5

[Zvuchniak]

Re: A HOLM starter guide

Maybe I am off-base, but just thinking out-loud are you sure you are getting a clean measurement from your mic? I'd look at the max. PCM level (should be on the bottom left of the holm impulse test page) and see if its a nice negative value. My best measurements seem to happen when that reads -2 to -5 db.

Just did that. Everything is the same :(

[killa]

Re: A HOLM starter guide

Maybe I am off-base, but just thinking out-loud are you sure you are getting a clean measurement from your mic? I'd look at the max. PCM level (should be on the bottom left of the holm impulse test page) and see if its a nice negative value. My best measurements seem to happen when that reads -2 to -5 db.

Could be but I doubt it. Good reason to have a reference speaker to measure.