1st REW Measurement

[mstailey]

Hello to all,
This is my first attempt after setup. I'm using my office pc speaker/sub as a test before I move on to the ht equipment.

Red = sub in the middle of the room
Purple = sub in the corner

My goal would be to utilize sub placement and room treatment first before applying any eq. So as brucek would state - is there a question in there? the answer is yes Based on the graph would placement / treatment work? What problems exist here in your opinion and what would you do to correct? I know it's a subjective question with only the graph but I want to make sure I've got the basics down using REW before moving on.




1stmeasure.jpg

[brucek]

The graph shows that your subs low end extension is ~45Hz. That would be consistent with PC based speaker+sub system. The signal as it rises from 35Hz down to 15Hz is basically noise exacerbated in the plot by the inverse meter calibration file.

But overall the response ain't too bad. You can see how the corner helps the bottom end, but it also suffers from a dip at ~150Hz. I would think by moving the sub around you could get a fairly smooth response. Treatment is ineffective at frequencies below about ~100Hz and so most of your peaks in the plot could be handled by placement, given that they aren't that bad.

Anyway, you obviously know how to use the program, so the HT room is next..

brucek

[Wayne A. Pflughaupt]

My goal would be to utilize sub placement and room treatment first before applying any eq.

You’re doing treatments in your office? Impressive.

Bass traps are the treatment usually used for low frequencies (although as brucek noted, their “reach” only extends so far), but I doubt you’ll want any in your office! Their primary function is to reduce extended signal decay times (aka “ringing,” for some inexplicable reason) and reduce the gap between the peaks and valleys. Judging from your graph, you don’t really have any peaks or valleys significant enough to warrant traps, so unless you want to reduce decay times there’s no reason for them.

Based on the graph would placement / treatment work?

Sure, placement often works, but you won’t know how well without graphs from the various locations.

What problems exist here in your opinion and what would you do to correct? I know it's a subjective question with only the graph but I want to make sure I've got the basics down using REW before moving on.

Keep in mind that a computer sub is low powered with a light duty driver, so you can’t get too aggressive with equalization. Most likely you won’t be able to turn it up as loud as you can now after equalizing.

That said, I picked up a car audio Alpine 7400 parametric EQ off eBay for my office system. Unlike the BFD, the Alpine small enough to sit on top of the sub – i.e., not take up a lot of real estate. It’ll only do a couple of bass filters, which is fine for a non-critical situation like this. A single broad filter would help bring the above 65-Hz area down to the below-65 Hz region.

Regards,
Wayne