lol, you avatar is a damn bug and I thought it was on my screen
Too funny, thanks for a great laugh!!!
Thanks, glad if I've done some cheering up!
Could you post those bugs in the HOLM thread on this forum? Do those bugs effect measurements?
One thing I need to ask about.First let me say that I'm a Newbie WRT measuring so if my question doesn't seem right please advise.But I have been getting this distortion in the bass region when i do measurements.It isn't in the drivers passband so it technically isn't affecting the measurement (Is That Right?). But anyway I find that I have to use too much gain with my Mic with Holm which will add more distortion.The way it was explained to me is that Holm likes the Mic to have to run too Hot WRT the gain for the microphone which I can attest to.To get the recording levels in the proper area gain has to be almost Maxed is there a way to cut that back some ?? Thanks in Advance for any assistance ! 
I proposed to measure the woofer very close because it then acts as a sort of “signal generator" for the microphone. This way he could verify if the high pass problem is acoustically, or if it is in his measurement setup. I do not think many useful results can be obtained from measuring a woofer that lies on the ground flat on his magnet.
As to the amount of DBs needed to make the spice, I just stitch curves together at the overlapping region.
For example:
I first measure the complete speaker at a distance of approximately 2 meters, as far as possible from any reflecting surfaces (closest reflecting surface is mostly the floor or ceiling). I then adjust the gating just before the first reflection (holm does this automatically, but it is very educational to move the gating forward and backward and look at the effect in the frequency response). This results in a reflection free measurement from 20Kzh down to for example 700 Hz (room size dependant).
This means that below 700 Hz the result from far field are not very useful. For this you can use near field measurement. The near field measurement result is then scaled so that the curves from farfield and nearfield overlap nicely between for example 700 Hz and 800Hz.
Below 100 a 200 Hz (the modal region) Dr. Geddes recommends to perform a steady state measurement, because the speaker and the room act as a single system (because of the large wavelengths involved). I believe he performs this kind of measurement as follows (maybe he can confirm):
- Noise measurement signal
- Spectrum analyzer software with some sort of slow time averaging function and 1/3 octave frequency averaging
- Speakers at the position where they will be used for listening to music (of movies)
- measurement microphone at the listening position (preferably slowly moving the measurement microphone in circles to how some positional averaging and a larger sweet spot)
- While looking at the spectrum analyzer, adjusting the equalizer or crossover to get the flattest response
- remove peaks only, do not try to remove a dips by boosting a frequency range (because the dips are caused acoustically, this is most of the time impossible anyway)
So in conclusion, to measure from 20Hz to 20KHz you need 3 measurements:
- Farfield
- Nearfield
- Steady State
But even more importantly is measuring the polar response of your speaker. You can only use far field for this, so try to go as low as possible in you far field measurement.
As you can see from the above, perform a single complete measurement of your speaker is quite some work, but if you manage to get a constant directivity polar response combined with a well behaved subwoofer region (Geddes recommends multiple subs for this), you will have a fantastic system!
I seem to be having the same issue.But after doing all those checks nothing changes. So any other suggestions would be appreciated.
I was thinking of trying some measurements with a different audio software something other than Holm to see if I'm still generating the anomalies.But as I'm fairly new to this setting up another Audio software without the gracious help of a member here seems to be far off into the future.
I'm getting to the point now that I'm ready to pack-in this measuring stuff.And just turn up the music and be happy with it.I have all this gear now and none of it works right.
Has anyone had any sucess with measuring on Windows Vista or Windows 7 operating systems, I think they stink.
Question for Dr. Geddes:
Did you make any progress to commercialize your program to display polar plots from the Holm impulse file format? This is the primary reason I still use arta, althought I like holm better(but the more I use arta, the more I like it also, it for sure also a fantastic program, with tons and tons of nice features!)
Did you make any progress to commercialize your program to display polar plots from the Holm impulse file format? This is the primary reason I still use arta, althought I like holm better(but the more I use arta, the more I like it also, it for sure also a fantastic program, with tons and tons of nice features!)
One thing I need to ask about.First let me say that I'm a Newbie WRT measuring so if my question doesn't seem right please advise.But I have been getting this distortion in the bass region when i do measurements.It isn't in the drivers passband so it technically isn't affecting the measurement (Is That Right?). But anyway I find that I have to use too much gain with my Mic with Holm which will add more distortion.The way it was explained to me is that Holm likes the Mic to have to run too Hot WRT the gain for the microphone which I can attest to.To get the recording levels in the proper area gain has to be almost Maxed is there a way to cut that back some ?? Thanks in Advance for any assistance !
No comments here guys !! No Help,I guess I'm the only one experiencing these issues.
I've had similar issues with other measurement programs. My Lenovo laptops is a piece of junk and is internally crippled to have the input feedback to the output. Using an external usb soundcard fixed that, but last I tried Holm still didn't work right on that computer. I use speaker workshop.
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Honestly I haven't had problems with soundcards (other than built in ones) so much as with the computer they're plugged into and the software running on it. It's usually just one setting you have to find somewhere once you determine this is the problem, but it can be really tough sometimes.
Latency High as Well
One other thing I noticed with the M-Audio control panel is that the latency is maxed out on my computer 4096. I have sent the Microphone back to Herb (cross-spectrum labs) he is sending me a new one, which he said he will check thoroughly before sending to me.So I hope we can make some progress soon as I will need to make some measurements very soon.
Thanks Pano !! For your gracious help/support
I'm keeping my
Thanks Earl & John too, any help or suggestions is worth a try. I guess I was posting to see if anyone else had experienced these same issues and if a solution was available.
One other thing I noticed with the M-Audio control panel is that the latency is maxed out on my computer 4096. I have sent the Microphone back to Herb (cross-spectrum labs) he is sending me a new one, which he said he will check thoroughly before sending to me.So I hope we can make some progress soon as I will need to make some measurements very soon.
Thanks Pano !! For your gracious help/support
I'm keeping my Thanks Earl & John too, any help or suggestions is worth a try. I guess I was posting to see if anyone else had experienced these same issues and if a solution was available.
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Great Scott Mr.Holmes I think you found it !!
Your right it seems John,but won't know for sure until I get the card back.Software setting issue !
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Great Scott Mr.Holmes I think you found it !!
I had an issue when I got a new computer with WinXP SP3 vs the SP2 I had previously. I had to update the driver to get the M-Audio card to work properly.