First sweep. Does it look normal?

[cruzmisl]

Hi All,
After 3 days of trying to get my SB Live to work with Vista and a dual boot OS, I decided to borrow a friends laptop with XP (should have done that 3 days ago )

Anyway, I followed the directions as best as I could. Created a cal file for my soundcard, loaded the cal file for my dB meter. I then hooked up the output to my MMC-1 and ran a speaker/subwoofer sweep up to 200Hz. This is what I got from my Submersive 1 and Rocket 850's. The crossover on my MMC-1 was set to 80Hz. Does it look normal or did I get a graph of garbage

Thanks,
Joe

[brucek]

Looks 'normal'. Generally you would first take a sweep with the mains disconnected and equalize the sub alone, then add the mains to check for interaction around the crossover area.

Looks like a pretty good response though. With a BFD you could get rid of the peak at ~45Hz and ~60Hz. You can also adjust the phase control on the sub and when combined with the mains (always use stereo mode and not any soundfield effects), you may eliminate the dip at 80Hz....

brucek

[cruzmisl]

Bruce, sounds good. I'll just unhook the main speaker wires and try it again. I have a QSC DSP-30 but I'm waiting for Mark Seaton to give me instructions on how to work it. I have no idea I'll post another sweep with the mains disconnected. I'll also try a full sweep with the phase switch at 180

Joe

[cruzmisl]

I tried just the sub and I get almost the exact same response. I then realized that even thought the speakers aren't on the MMC-1 is still crossing the signal at 80Hz so I tried setting the speakers to large but I don't get an LFE signal when I do that. I then turned up the crossover to 160Hz but I still see a large dip at 80Hz. My Submersive doesn't have a phase switch. Maybe my DSP-30 does, I should take a look at the software. Anyone have any ideas how to get the DSP-30 to interact with REW?

[brucek]

I'll also try a full sweep with the phase switch at 180

Only need to sweep from 15Hz to 200Hz when doing this since you're looking at ~80Hz area.

I tried just the sub and I get almost the exact same response

That's a bit confusing. With the sub only you should be tracking the target as shown in your first graph as the dropping line. The bass management of your receiver should be crossing the sub at 80Hz as well as your main (when set to small). Why was the sub not tracking the target?

If you have a dip at 80Hz with the just the sub playing, then it's the room and not the interaction of the sub and mains. That's fine. Sometimes once you combine the mains and sub, the phase switch will clear the problem.....

brucek

[cruzmisl]

If I didn't sweep below 15Hz Mark Seaton would be disappointed with me I'm going to hook up my DSP-30 when the inlaws leave and see what happens. It comes with it's own software but I have no idea how to work it. I sent Mark an email, he knows how so I'll just wait and see.

[Wayne A. Pflughaupt]

Like brucek said:

You can also adjust the phase control on the sub and when combined with the mains, you may eliminate the dip at 80Hz....

Maybe you’ll get lucky and the one at 40 Hz will go away with it. Just too much of a coincidence that they’re exactly one-octave apart...

Regards,
Wayne

[cruzmisl]

Here is a sweep with the sub/mains (sub reverse polarity) smoothed out the 80Hz dip quite a bit. I get 16 GIK acoustic panels tomorrow and then I need to try and smooth out the curve. Any tips or tricks?

[clubfoot]

Unless you're getting bass traps the panels will mostly alter the upper end. As has been suggested take a plot of your sub only, disconnect the mains at your pre/pro or speakers and post it. The plot should follow the blue target line and fall away. Change both the location of the sub and seating to find the smoothest curve. Your curve is not bad, but could be better. Remember that small location changes can make a big difference.

[cruzmisl]

I did get 4 bass traps so we'll see if they make a difference. The response is almost a mirror image without the mains but the dip at 80Hz is more pronounced.