HOLMImpulse: Measurements in practice

[wintermute]

This should get you started A HOLM starter guide - Techtalk Speaker Building, Audio, Video Discussion Forum

I've had a look but I can't find the tutorial that talks about locking time zero (something that I find very useful for designing crossovers) but that is getting into more advanced territory so the above should be good for getting going

Tony.

 

[jmw1937]

Thanks very much. It looks helpful, but as a series of HTML pages, it's not very accessible.

 

[WithTarragon]

Thanks very much. It looks helpful, but as a series of HTML pages, it's not very accessible.

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You are getting some useful software for free.
You are getting some useful advice for free.
I am sorry that you do not find it convenient.

 

[jmw1937]

I didn't mean to offend anyone. It was meant to be a constructive comment. I didn't go as far as asking for a PDF, which is how such data are very often distributed.

 

[Nohabla]

Measure technique

Hi,

I'm testing Holm and have some questions:

1. I'm using Behringer ECM8000 mic, what is the best way to place it, pointing up, or directly at the speaker?
2. the phase is very different on these two measurements is it because of floor and roof reflections?

Mic pointing forward:
https://drive.google.com/open?id=0B-3zACpn_TnaUVA2eWo2WmxqWlU

Pionting up:
https://drive.google.com/open?id=0B-3zACpn_TnaTGVyVjRQTnV6TjA

This is taken indoor, using the active crossover behringer cx2310 24db filter at 1k2.

 

[Pano]

The phase if different because the two measurements are polarity inverted. Look at your impulse.

I used the ECM8000 tilted slightly toward the speaker. Not vertical, but about 45 degrees.

 

[John Sheerin]

The mic will become directional at high frequencies. I would point the mic at the speaker. You can see the effect of orientation of the mic by keeping the tip in the same place and rotating the mic, taking measurements at various angles and comparing them. If you are not gating out all reflections, this effect may be lessened.

 

[Nohabla]

Hi,
Thanks will do some more measuring when i get the time, have also acquired a DSP so i can experiment with delay. Have read that Phase difference between Bass and treble isn't that audible, what's your thought about that? Is phase linearity something you strive for?

 

[keantoken]

Has anyone gotten HOLMImpulse to work in Linux under WINE?

 

[NEO Dan]

REW room EQ wizard is an option for Linux users.

 

[pet007]

Hi, I am using HolmImpulse many years. But yesterday, I wasn't able to run it anymore (under Windows 7). I've tried to uninstall/reinstall both x86/64bit versions manytimes - nothing works :/ Please, any tips/hints before complete Windows 7 reinstall ? Thanks a lot.

 

[jmw1937]

I wouldn't reinstall Windows. It may be that new security features are stopping HolmImpulse working. I see that it has not been updated to work with Windows 8.1 or 10. If you can get no answer from HolmImpulse company, you may have to choose a different application, of which there are several, but not necessarily free.

 

[gedlee]

I run Holm in Windows 10 all the time.

 

[300Z]

I also run Holm on my Windows 10 tablet without any issues.

 

[wintermute]

You will likely have to change the explorer settings to allow you to see hidden files and system files to do this.

Browse to c:\users\your_user_name\Appdata\Roaming\HOLM Accoustics\HolmImpulse

Back up the files there (if you want to potentially get back measurements you have done) and then delete everything under the folder.

Maybe do a computer restart as well, and then hopefully when you start holm the next time it will work fine, and be in default configuration.

I've had to do this a few times.

Tony.

 

[Techland]

I started to use HOLMImpulse under Windows 10 with ASIO, and basically it works - phantastic for a program of 2009!

After the installation the program did not remember any settings. So I followed the above advice, deleted all files in the specified directory, and now settings are ok on restart.

Except for one really annoying thing: it doesn't remember window size, window position, or window subsize (I tend to reduce the size of the Impulse Response window).

So my question to long time users: is that normal? I did not find any mention of position and size in the options xml file.

 

[wintermute]

I'd never noticed before but yes it always opens the same size in the same position (ie if you change it it goes back to what it was). This is on Windows 7.

I'm normally using it on my laptop which has a small screen so I just maximize it.

Tony.

 

[Techland]

Thanks. That's what I expected, and obviously this will never be fixed.

I have now spent some measurement time with HOLMImpulse using it on modern top AD/DA converters. My observation is that:

- the option 'Highpass result to start frequency' adds significant THD below 50 Hz. Fortunately not working with a mic this option can be switched off without any issues, it seems.

- the Detect Time Zero Interpolate (Sample Fractions) mechanism causes THD bumps starting at exactly 2 kHz. Manually changing the value by a tiny amount gets rid of it, but then the phase display is way off.

- THD below 30 Hz is not working correctly near full input level (0 dBFS). Value is better at -0.5 dBFS, and fully correct at -1 dBFS. This is a problem in the program, not in my setup or AD/DA.

- Impulse Response AutoZoom does not work correctly. And because the program forgets the manual Zoom state one has to recenter the typical AD/DA filter response view (-1 to +3 ms) after every restart.

I tried a lot of the different settings, but none was able to solve the listed issues. If one knows how to I would be happy to hear it. Otherwise I think I will not continue to use this software for my kind of measurements (analog/digital electronics). It's a pity as the GUI has everything that one needs for that, and measures quick and easy...just not reliable/accurate enough...

 

[Shaun]

^^^^ Perhaps it's not the right tool for your purpose? Have you checked out Right Mark Audio Analyzer?

 

[wintermute]

I've not relied on the HD results of holmimpulse, I hadn't analyzed as you have but could see that there were problems.

If I want HD measurements I use REW, which seems to give much better results. I like Holm for it's simplicity, but I have started to use REW more now.

Tony.