# First REW Results - Comments?



## brendans13 (May 11, 2011)

Hi all, this is my first post here but i've been doing a lot of reading over the last couple of weeks.

I recently acquired a new SVS PC12-NSD sub, and have decided to go a step further than I normally would to calibrate it and get it sounding as good as it can.

I bought a Behringer UCA-202 USB sound card for my laptop, and a Radio Shack 33-4050 Analog SPL meter.

I followed the guides and I am pretty sure I calibrated my sound card and SPL meter properly.

My room dimensions are 3600L x 4800W x 2700H or 11.8L x 15.8W x 8.9H in feet.

This is my lounge room and it has polished wooden floorboards.

I have attached a PDF of my room layout.

My full setup is as follows:
Onyko TX-NR708 (Audyssey MultiEQ)
SVS PC12-NSD
PSB Alpha T1's
PSB Alpha C1
Definitive Technology ProMonitor 600's (Front High's and Surround's)

This is my very first result last week with everything how it was before I started tweaking using REW.










Here are todays results. Since the first measurement last week the sub is now further tucked into the FL corner (was previously around 200mm spaced out from both walls), and speakers are now around 250mm from the front wall (previously they were around 400mm out)










Now with phase at 180deg.










Now with sub distanced tweaked to 4.05m (I tested all the way from Audyssey's 4.80m down to 2.45m and this was the best).










All results combined.










For curiosities sake I also did a comparison of Audyssey vs No Audyssey of Result 3 (which is where I am at now) to see what it was doing.










I am quite happy with the results. It seems that there is quite a pronounced dip at 64-72Hz that I can't get rid of even if I cross the speakers down to 60Hz. Maybe something to do with the room?

Also, it seems to be a little all over the place above 100Hz. Is this normally the case, or could there be something else affecting this?

That's it for now. Appreciate any comments & criticism.

Thanks.


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## robbo266317 (Sep 22, 2008)

That's quite a nice low end response and you are correct in saying it is room interactions causing the dips. 
This can be verified by doing a close mic plot of your speakers and comparing the graphs. 
The aproach you have taken by making small changes and remeasuring is the only way to find the best position. I would suggest reading here also if you haven't already done so. http://www.realtraps.com/art_room-setup.htm

Cheers,
bill


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## brendans13 (May 11, 2011)

Couldn't leave it alone so I decided to re-run Audyssey.

This is as good as I can get it now.


















I must have forgot to save the previous results so I can't directly compare them, but it seems as though it is not as good as I had it .


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## shinksma (Aug 12, 2010)

That looks pretty good to me! That dip at 68Hz or so will likely never be noticed (unless you listen to slowly sweeping sinewave bass notes  ). Hmm, maybe that's a good name for a sludge-metal band: Slowly Sweeping Sinewave Solution. No worse than "SunnO))))". Yes, that really is the name of a sludge-metal band...pretty good too, if you like that kind of, um, sound-scape music. I like it, but it isn't for most folks.

Anyway, back to your graph:

Try turning on some one-third octave smoothing or similar in your graphs - that is generally thought to more closely mimic what we actually hear, vs what the machines measure. You might find the graph gets remarkably smooth as a result.

Oh, and just give the system a listen: if it sounds good, then trust your ears. On paper it looks like a very nice response (I am a little envious of your flat response below 20 Hz - I would personally be curious to see what the response is down to 10Hz or so).

shinksma


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## brendans13 (May 11, 2011)

Nice band name! lol

Thanks for the comments. I am very happy with the low frequency response of this new sub!

I personally run the sub at around +4db, which may be a little too much bass, but it is new and i'm not over it yet.

Here is a graph that goes down to 10Hz.










And here is one from 10Hz-3kHz with 1/3 octave smoothing.










Does the frequency response look ok in the higher frequencies?

Is there a way to insert a "perfect" target response curve to compare it with?


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## shinksma (Aug 12, 2010)

brendans13 said:


> Does the frequency response look ok in the higher frequencies?
> 
> Is there a way to insert a "perfect" target response curve to compare it with?


Yes, the frequency response looks pretty good in the higher frequencies too. 

A "perfect" response curve for SW + Spkrs is really just a flat line at whatever SPL you are trying to target as a reference level. You can also display a target curve for a SW crossed-over at a chosen frequency, so you get the appropriate drop-off.

You display the target "curve" by selecting the checkbox next to "Target" on the EQ Window. You alter the target setting via the Target Setting controls in the upper right (second one from top).

AFAIK looking at the REW 5 Online Help files - I used REW 4, and haven't needed to upgrade yet...

See the specific help page here:

http://www.hometheatershack.com/roomeq/wizardhelpv5/help_en-GB/html/eqwindow.html

shinksma


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## DanTheMan (Oct 12, 2009)

Some say target room curve should look like this:








Yours looks good.
Dan


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## brendans13 (May 11, 2011)

Thanks for the pic.

I thought I remembered reading somewhere that there is a downward slope towards the higher frequencies.


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## DanTheMan (Oct 12, 2009)

Don't get hung up by the grass above 200Hz. Your room would have to be anechoic to not have it--and that's no fun at all.

Dan


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