subs and room eq

[Winger]

I watched the UMC setup video and was intrigued by multi-band sub EQ between 22 and 250 Hz (I think that was the frequency range anyway).

With the ability to tweak levels up and down to address room modes, why would it be necessary to have a sub that was ruler flat to begin with. Granted, if the frequency response is flat, it should make the room correction easier to perform, but is it necessary? Just wondering how many sins the EQ (specifically the EmoQ) is capable of correcting.

Thanks

-Wing'

[Accurus]

I would read the Velodyne SMS-1 manual as to why room placement should be the first option before room correction.

Essentially if you are having huge dips in a certain position. Room placement could fix those bumps without wasting huge amounts of power trying to correct those dips. the eq can boost your-6DB dip in the 40hz zone lets say. But hows much amplifier power do you want to waste on that? And do you have the juice to spare? With fewer big bumps like that you have more amplifier power and more headroom. Headroom is something an EQ can emulate.

[jmilton]

Nice long-haired...


Essentially, you place it in a spot for the flattest response and your corrections should be final tweaks. To use an EQ program means you have to make BIG adjustments to flatten things out, and BIG adjustments will usually knock things out of whack elsewhere on the curve and eventually you will never catch up to the mess your making.

Proper placement trumps EQ alone. But, proper placement WITH EQ is magical!

[Winger]

Long haired,,, you mean the dog? Yeah, finally got the avatar picture thing figured out...

Gordon Setter, big bundle of energy. Wish I could harness it.

Without sophisticated measurement equipment, how do you determine the best placement? I've heard that to put the sub in the listening position and walk around until it sounds loudest identifies the spot, but that seems imprecise. If done in that manner, what should be used for a test tone, white or pink noise? Or should I just use the level adjust feature on my LMC-1?

One real limitation to determining the ideal position is interconnect length. I don't have a balanced in on the sub amp (older version of non-servo-direct Rythmik) and I'd be concerned about hum if the run gets too long.

Thanks for the input!

[jmilton]

Ha...with the legs cropped. I thought it was a weiner dog.

If you provide an e-mail address, i have a "white paper" given to me from Kevin Voecks from Harmon International on proper sub setup/locations that I would be glad to send to you. Very good tips...

[Accurus]

Winger,
Have you a friend with a Velodyne SMS-1 that you can borrow? It can give you a visual response curve so that as you change your sub position you can see the difference in real time of the frequency response.

[Winger]

Cool, thanks. [e-mail]

Probably best to copy and paste the address. It's commonly mistyped as "citilink" No third i.

Actually, her legs aren't cropped out of the picture, she's chest deep in snow on a full-on-dead-run looking back over her shoulder. It's actually a pretty cool picture when seen in full size.

-Kurt

[Winger]

Unfortunately, I don't know anyone who has that kind of equipment. I do have a measurement microphone (Dayton version of the Behringer ecm 8000), but don't really have software to utilize it.

[Accurus]

Hmm, well maybe the best method might be to get a 20hz-100hz test tone. Make sure that it is a long tone. Then use your mic and a pen to try and graph by hand what it looks like it is doing in there. It will get you a good close start. Then go to an Auto EQ from there.

[DYohn]

Jan 22, 2010 16:49:58 GMT -5 Winger said:

Unfortunately, I don't know anyone who has that kind of equipment. I do have a measurement microphone (Dayton version of the Behringer ecm 8000), but don't really have software to utilize it.

www.hometheatershack.com/roomeq/

[Winger]

Jan 22, 2010 17:08:25 GMT -5 DYohn said:

Jan 22, 2010 16:49:58 GMT -5 Winger said:

Unfortunately, I don't know anyone who has that kind of equipment. I do have a measurement microphone (Dayton version of the Behringer ecm 8000), but don't really have software to utilize it.

www.hometheatershack.com/roomeq/

Now that looks cool. I'm going to have to look into that further.

Thanks!

[Mr. Ben]

Jan 22, 2010 18:01:54 GMT -5 Winger said:

Now that looks cool. I'm going to have to look into that further.

Thanks!

emotivalounge.proboards.com/index.cgi?board=tech&action=display&thread=6465

[Raven]

You may find some useful info there as well:
emotivalounge.proboards.com/index.cgi?action=display&board=tech&thread=8770&page=1#131961

[TUBEHEAD EL34]

"With the ability to tweak levels up and down to address room modes, why would it be necessary to have a sub that was ruler flat to begin with?"

Because a flat sub means that it is better designed and will sound better-period. Compensating with an EQ does not make a sub play tighter, faster, or more transparent. Most high quality subs will be almost ruler flat with some dipping sooner than others at the very lowest frequencies but that is to be expected. A sub with response like a lie detector is a sub that is best put on ebay!

My experience with using a behringer BFD EQ is positive. I disagree with the poster that said that making corrections causes problems elsewhere. My response is almost ruler flat below 100hz. There are very few who are able to achieve flat response by simply moving a sub around (although some areas measure better than others). Some form of EQ, or room treatment is almost always necessay.

With regards to room modes (peaks) and room nulls (dips), while the peaks can be easily EQ'ed, the nulls are extremely difficult to boast and adding more than 3db is never recommended because you lose amplifier headroom.

I hope you have better success than me with your built in EQ. My experience with receiver and pre/pro EQ's is that they leave much to be desired. I achieved much better results by adding the behringer EQ and MANUALLY tweaking myself. Mind you you will need the EQ itself, an SPL meter a computer, and software to do it.

www.hometheatershack.com/roomeq/

[jedinite24]

Stupid questions coming up..

If you don't have any options in subwoofer placement due to furniture constraints and size constraints of the sub should one bother with trying to smooth things out with an EQ? My sub is a Velodyne SPL 1500R and the only EQ that will work for me budget wise and size wise is the EQ.2 from Elemental Designs.

My HT room is less than 1300 square feet. I watched Watchmen this past weekend and to my ears everything sounded fine.

Seeing all this talk about subs and EQs is just making me wonder though if the sound can get better.

Some background..

I have a Velodyne SPL 1500 R that is used for HT only. My processor is an Outlaw Model 990 and I watch Blu Rays and DVDs from an Oppo BDP-83. The Model 990 is set to 7.1 Direct whenever I use the Oppo BDP83.

Thx JD

[TUBEHEAD EL34]

The only way that you will know if you should EQ is by measuring. the simplest way is to pick up an SPL meter from radion shack, get some chart paper which breaks down the frequencies (ie from 20hz to 100hz), run a sweep through the sub (you can download them and burn them to a cd), and plot the response on the paper.

If you see major peaks or dips (above 3db), this ALWAYS means sound is bad. You may not know any other sound than what you have now, but if you achieve a flat response, you may realize what you have been missing for the first time.

BTW, much easier to learn the REW software (free), and plug the SPL into your computer. You will find that you will run sweeps all the time and the manual way is time consuming but it is better than nothing.

The behringer feedback destroyer allows you to download your filters directly with a USB and is quite affordable.