The wonders of going Dual

[dmass]

I recently added a second TN1220 to my setup. I am now running a dual cylinder HSU setup. I have a BFD PEQ and use REW (Room EQ Wizard) to adjust my sub/room EQ response.

I purchased the second TN1220 not for output, but in an attempt to smooth out the response in my HT.

So far I am just getting started with tweaking, EQ'ing and placement experiments. But my first effort is looking REAL GOOD!

Graph below is 2 TN1220's with no BFD EQ filters at all. It is also in the first (and best cosmetically) placement locations. Because I am going for smooth response and NOT headroom output, I am not co-locating my subs, but instead spreading them around the room.

Green line is one TN1220.
Blue line is dual TN1220's.

Note that the dual configuration has almost completly fixed my 50-70hz problem and given me an extra few db of extention in the low end. (measured at my listening sweet spot.)

[Ddavidson]

Thats the great thing about multiple subs in the correct locations. It can help balance room issues, however caution should be exercised if people don't have good measuring equipment. The risk without good measurement using mutiple locations (rather than stacking) is that you can also create problems such as cancellation.

In your case its worked as it should and I have no doubt you have noticed better reproduction with your 50-70hz problem fixed.

Good deal.

Ddavidson

[dmass]

How does one use REW to measure or detect phase issues?

I have the 2 TN1220's + HSU Bass Optimizer, 2 full range main speakers with useable base to 40hz, and a BFD PEQ. My receiver is set to Main's = LARGE, but it also sends the LFE/Low's to both SUB and MAIN's in that setting.

The one thing I do not have the ability to control is the phase going to the TN's with this setup.

Any recommendations for measurement or listening to detect phase issues and how to deal with it in my setting?

[Pete_Hsu]

That is a pretty incredible difference, dmass, nice job!

Where are you currently placing each subwoofer?

The frequency response graph will tell you if one unit is out of phase with the other. If you see large dips in the frequency response which aren't there when the phase in inverted on one of the subs, then that is a good indication that one unit is out of phase with the other.

[dmass]

I have started a discussion thread (with additional waterfall graphs) on AVSFORUM. See here: http://www.avsforum.com/avs-vb/showthread.php?t=1136101

Sorry if it is bad form to cross post to another forum.

My basement HT room is a little odd shaped. The overall dimensions are 26ft long x 12 ft wide by 7.5 ft floor to drop ceiling. The floor to 1st floor subfloor distance is 8.5 feet. In parts of the room the ceiling is 6.5 foot tall and parts of the room are a little wider.

One sub is in a little cubby or alcove on the right side wall about 30% of the room length back. The second sub is also on the right wall about in the 50% mark.

See previous discussion on the "cubby" location.

http://forum.hsuresearch.com/showthread.php?t=4549&highlight=cubby