VTF2.3 and MBM-12 Calibration

[kmitchell]

Hi All,

I'm getting really close to ordering an MBM-12 and I have a question about calibration. I've seen in a few posts where the Sub and MBM are calibrated individually with one or the other turned off and I'm not sure I understand why you would want to do that.

If you are feeding both units the same receiver signal with the receiver crossover set at 80Hz and the Sub crossover set to "IN" at 50Hz won't they naturally just play their positions based on the test tone frequency being played?

If there is some overlap between the two wouldn't you want both units to be turned on during calibration so you can take that overlap into consideration while calibrating?

Thanks for any guidance.
Ken

[bsoko]

Hi All,

I'm getting really close to ordering an MBM-12 and I have a question about calibration. I've seen in a few posts where the Sub and MBM are calibrated individually with one or the other turned off and I'm not sure I understand why you would want to do that.

If you are feeding both units the same receiver signal with the receiver crossover set at 80Hz and the Sub crossover set to "IN" at 50Hz won't they naturally just play their positions based on the test tone frequency being played?

If there is some overlap between the two wouldn't you want both units to be turned on during calibration so you can take that overlap into consideration while calibrating?

Thanks for any guidance.
Ken

How can you calibrate the two together, you want the bass from each sub to reach your ears at the same time?

Calibrate the MBM at 73 spl (by volume control) and the main sub at the same 73 spl. Then take a reading of the two together and they should read approx 76 to 78 spl and don't worry about the overlap.

The reciever sub spl level (pink noise) should be set at "0" (always start all speaker & sub spl levels at "0") then adjust the volume of each sub when calibrating. The MBM (nearfield) volume should end up at around 7:30 ish and the Main sub (farfield) around 9. The reciever sub level stays the same for all subs and the volume is dialed in each at differnet setting.

All of what I have written is how I set my subs up. For the real deal on Sub setup, etc: http://www.avsforum.com/avs-vb/showthread.php?t=1004573

Bill

[kmitchell]

Thanks Bill.

I wasn't even thinking about the volume controls on the sub amps themselves. So if I understand correctly you set the volume level on each sub one at a time to match the spl level of the subs then you go through the normal calibration as if there's only one sub connected (ie. using test tones and adjusting the sub output level at the receiver)?

What kind of test tone (pink noise?) do you use to initially match the spl levels of the sub and mbm?

Thanks for the help,
Ken

[bsoko]

Did you setup your speakers with a spl meter using the "Speaker Level" pink noise output on your reciever? If so, the list should include your subwoofers. Click the noise on and leave it on, and do one sub at a time. Then turn on all the subs and check your output. In "War of the Worlds", play the scene where the ships are coming out of the street at the church. That scene has plenty of good bass:D :D . That's how I setup my subs.

Bill

[kmitchell]

Hi Bill,

Now I've got it. Yes, I used pink noise to setup my speakers and then the test tones from the HSU test CD to setup the sub.

Thanks,
Ken