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Using Autocal with 8250A's and 7060B

blt1, modified 10 Years ago.

Using Autocal with 8250A's and 7060B

Youngling Posts: 3 Join Date: 2/1/11 Recent Posts
Hello,

I have a 5.1 setup with 8250a speakers, and a 7060b subwoofer. I am running analog signals from my interface (Lynx Aurora) into an external bass manager (Blue Sky BMC), then running each output from the BMC into the analog inputs on all the 8250a's and 7060b. I read somewhere (I can't find it now) that it is possible to use Autocal when using an analog subwoofer, as long as all signals are run into the 7060B before heading to the 8250A's (so it is correctly bass managed). Since I have an external bass management system, I use that for bass management instead, which should effectively be the same.

Now, when I run GLM and Autocal, the 7060B obviously does not show up. However, I assumed it would be accounted for since the sine wave sweep would jump from the subwoofer to the mains at the crossover point. I was confused to realize that the sine wave sweep does not originate at the computer, but at the loudspeakers themselves, so the subwoofer is NOT accounted for in the auto-correction. Instead, it acts as if each loudspeaker is a "full range" speaker.

How do I tell Autocal that the monitors ARE indeed bass managed?

Also, even if I were to use the 7060B as the bass manager, it still would not account for the subwoofer and bass management because the sine wave measurement sweep comes from the speakers, not from the computer (so it completely skips any bass management system, whether it is the BMC or the 7060B).

What is the process for using Autocal with an analog subwoofer, so Autocal can correctly account for bass management?

Thanks for your help!!!
Brett Thomas
ilkka-rissanen, modified 10 Years ago.

Re: Using Autocal with 8250A's and 7060B

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
Hello Brett,

You don't need to worry about the AutoCal accounting for the bass management. The main speakers are always and every time run as full range (even if a DSP subwoofer is used) during the AutoCal sweep and therefore also corrected as full range. This is done so that the frequency response of the whole system stays at flat as possible even if the crossover frequency is being varied from the "standard" 85 Hz. So main speakers are first corrected flat and then bass managed (either by a Genelec subwoofer or by an external device) at the selected frequency.

Naturally your analog subwoofer isn't being corrected by the AutoCal in any way. So you need to set all the settings (level, phase, bass roll-off) manually, preferably with a help of a room response measurement program like WinMLS, Room EQ Wizard, ARTA etc.
blt1, modified 10 Years ago.

Re: Using Autocal with 8250A's and 7060B

Youngling Posts: 3 Join Date: 2/1/11 Recent Posts
Hi Ilkka,

Thanks for your help. That does make sense to make sure all channels are flat across the full range before bass management occurs. I guess my problem with it is that Autocal wants to use 3 out of the 4 notch filters below 85Hz on all three front channels. I would much rather it use those filters above 85Hz, since low content will all be redirected to the subwoofer. I guess that's what manual controls are for! :)

On a different note, I realized that the first time I ran Autocal, it wrote the levels to the 3 front speakers way too low even though I told it to use full volume. I was using 1.3.1, which is the version that came on the installation disc, so I downloaded and installed 1.4 from the website, and now Autocal won't run at all. When I get to the actual test screen, the "Activity" bar is already lit up, but is not moving (appears locked up). I can still type in the serial number field and click the "P" button, though. However, when I do so, the Info field says "Calibrating Input. . . ", but hangs there forever until I tell it to cancel. I'm tempted to go back to 1.3.1, but that version says it only works with mics up through 101250 (mine is 101475), even though it did work once (and only once). I would prefer to stay with the most recent version, but I'm not sure what is causing it to lock up. I have a feeling it might have something to do with Digidesign's Core Audio driver trying to override the Genelec interface. The Genelec interface does not show up in AudioMidi setup, or in the Sound Control Panel, but I'm not sure if it is supposed to? Twice, I have deleted version 1.4 and the GLM Preference file then reinstalled 1.4. Still locks up. Both times I deleted the app and tried to reinstall it, the install screen says "update" next to GLM, so there must be a file that I am missing when trying to uninstall it.

Any advice on what should be selected in AudioMidi setup? Should the Genelec interface be visible?
Is there a way to fully uninstall GLM in order to do a clean reinstall?
Are there any known issues with my setup (below)?

Any help would be greatly appreciated, as I'm currently stuck with a miscalibrated system, and no way to fix it!!!

Here is my setup:

3GHz Mac Pro 8-Core Intel
10.5.8
Protools HD 8
Lynx Aurora 8 (used as ProTools HD interface)
GLM 1.4

Thanks again!!!

Brett Thomas
blt1, modified 10 Years ago.

Re: Using Autocal with 8250A's and 7060B

Youngling Posts: 3 Join Date: 2/1/11 Recent Posts
Hi Ilkka,

Just a quick update: I did get Autocal to run again. If anyone else is having a similar issue, I'll post below what I did to get it working. Otherwise, thanks so much for your help!

Sincerely,
Brett Thomas


How I got Autocal to stop locking up during measurement:
I found every file named "GLM" or "Genelec" on my system and trashed them, then found three (not sure why I had three!) different versions of X11, all of which I also trashed. I downloaded the most recent version of X11 (2.6.0) from the developers website (http://xquartz.macosforge.org/trac/wiki/X112.6.0), then installed GLM 1.4 again (without letting the GLM installer install X11 itself). Then I made sure that my audio interface and master clock were off, and turned my "default input/output" to the "system in/out" in AudioMidi Setup to make sure that Digi CoreAudio wouldn't try to intrude. GLM and Autocal worked like a charm. Didn't stall or freeze one bit.

One very strange thing, though, is that my computer will not start up if the included GLM software CD is in my CD/DVD drive. I thought this was a fluke yesterday after I first installed version 1.3.1, but it has happened every time since. It will mount just fine if the computer is already on, but if the CD is in the tray when I startup or restart my computer, it locks up at the gray screen, before the Apple logo even appears. I have to force the CD out before it starts up. I realize that this is probably an isolated incident due to the fact that it is a CD-R, and my drive may not like it, or the disc is possibly damaged, etc, but strange nonetheless!
ilkka-rissanen, modified 10 Years ago.

Re: Using Autocal with 8250A's and 7060B

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
Hi Ilkka,

Thanks for your help. That does make sense to make sure all channels are flat across the full range before bass management occurs. I guess my problem with it is that Autocal wants to use 3 out of the 4 notch filters below 85Hz on all three front channels. I would much rather it use those filters above 85Hz, since low content will all be redirected to the subwoofer. I guess that's what manual controls are for! :)

Hi Brett,

Yes, in that situation the notch filters below 85 Hz are somewhat useless. Although maybe not totally because crossover filters are no brick wall filters but they have some certain slope instead, so if you have a strong room mode say at 50 Hz, an 85 Hz crossover filter might not attenuate it enough and you will see it still effecting your system frequency response. In that case you should attenuate the mode with a notch filter.

Also if for some reason you want to lower your crossover from 85 Hz, having the mains calibrated flat across the full range makes a lot of sense. :)

I have forwarded your notes about the AutoCal lock up problem to our GLM development team. I will let you know how they respond.
ilkka-rissanen, modified 10 Years ago.

Re: Using Autocal with 8250A's and 7060B

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts

I have forwarded your notes about the AutoCal lock up problem to our GLM development team. I will let you know how they respond.

Notes from our dev team: GLM v1.3.1 had a PowerPC version of X11 when v1.4.0 has an Intel version. Obviously it should have been updated along the GLM, but for some reason your system had many versions which caused the problems you noticed.