First Sub Readings

[t6902wf]

Here are readings from my dedicated 1800 cubic foot room.
I believe they are correct. There is no smoothing.

The room has a drop ceiling and I put 12 x 24 of batt fiberglass around the perimeter as a bass trap (I read somewhere that would help for the money it was worth a shot).
The walls are treated with 1" fiberglass.

I am running 2 HSU USL-15's I am happy with their performance.
The first graph is with the ULF-Trim set to 16hz



The second graph is the same position as the first with the ULF set at 50hz



The last graph is with the ULF at 50 and the position changed The first two the subs were centered between the center and main speakers. This graph the subs are pulled in as close to the center as I can.



These are without Audyssey which I normally run
Any suggestions or comments? These look a little to smooth?

Thanks

Biill

[Wayne A. Pflughaupt]

Yes, they are amazingly smooth - that pretty unusual. We'd need to see a waterfall graph to judge how well the bass traps are working.

How does it sound? I would expect all that energy below 20 Hz might make things sound "heavy." But then I don't have subs that get that low, so I can't definitively say that's a bad thing...

Regards,
Wayne

[t6902wf]

Thanks for the reply Wayne. It sounds great. On test tones I can't really hear much below 20hz so I would only feel that energy.

Is there some error I could have made to make the graphs so smooth? Is there a reason for EQ

Here is a waterfall I did quickly this morning.



I would like to plot the mains next. I have read that the Radio Shack meter is not up to that task. What mic should I use? Do I need any special connectors or cables for it?

[brucek]

Any suggestions or comments? These look a little to smooth?

As if one HSU USL-15 wasn't enough.
I wouldn't rely on the data below 10Hz unless you have a special microphone and cal file that supports those frequencies, but down o 10Hz, it certainly is a fine response.

I would take Waynes suggestion and examine the waterfall plots to see what the decay looks like.

brucek

EDIT: cross post.

Here is a waterfall I did quickly this morning

Use the standard vertical axis of 45dB-105dB with a horizontal of 10Hz-200Hz and set a target of 75dB and shows us again. Set the mode to LOG.

[t6902wf]

Here is another waterfall I did this morning. I am suspect of it I can't recall if I messed around with something, I was in a rush.



Excuse my ignorance what does this tell you. The decay of the signal?
If so it appears I have some problems up to 40 hz? Does the fact that it is down in the 50db range make it more acceptable?
I'll rerun it tonight per Bruce K's settings.

[brucek]

Set the mode to LOG rather than LIN using the Freq Axis button in the top right corner of REW.

With a waterfall you're basically looking at a response measurement with the time domain added . If you've selected a time range of 600msec, then it will be in 30 slices of time of 20msec (600ms/30) each after the sweep.

Slide the Slice control over to 0 and you're looking at your frequency response graph. Now move to slice 1, and you're looking at the sound after 20msec, and so on to 30 slices at 600msec. If you see portions of the sound still persisting (ringing) at 600msec with any level that you might actually hear above room noise (> 45dB), then you can see that you would like that decay time to be reduced if possible.

One thing you have to be sure of is that the ringing signal is just that and not background noise in the room from a furnace or fridge etc.... Usually a test with the Spectrum analyzer (set up to listen to noise) will tell you that, or simply using your own ears to be sure you measure in a quiet environment..

brucek