Two subwoofers in smallish HT room?

More reading on out-of phase subs.

http://www.audiocircle.com/circles/viewtopic.php?t=15708

Dave

Eldartford

Phase inverted rear sub is being put to use by a few people these days...along with myself.

I read about this at Vmps's web site around 8 years ago so gave it a listen and loved it. There was also a long thread at the Audiocircle forum regarding this about a month ago. If I recall, the guy that posted on it had 4 subs.

Dave

Eldartford

Sounds like you use a high X-over setting with your subs...boom should not be a problem.

Dave

The out of phase hook-up method is used more for fun...has nothing to do with boosting SPL or trying to effect or not effect room modes.

Two subs in front and two subs in rear (out of phase) give deep bass sound effects in movies a roll-through wave effect that can add to the fun...thats it in a nut shell..fun.

For music only types...this may not be fun. It may also not be fun for those that use there subs in the freq ranges where Boom takes place...very deep bass can not Boom.

Dave

Eldartford

I guess I'll just agree to disagree then...my findings are very different than yours. I would hate to be standing in the room when those 20hz booms take place though...should take no more than 100,000 watts or so to blow the windows and bring down the roof!!!

Dave

Eldartford

I also run three subs, your measurements go right along with my findings. My Onkyo M-504 sub amp has large power meters and confirm that very little power is needed to shake my 4,800 cubic ft. room on it's cement slab floor.

I do indeed have all the tools to measure my room in 1db increments and am very lucky that it measures very smooth over-all with no large peaks/dips down to 17hz...I did build the room as a " room with-in a room"... with my sons help.

I guess where we differ is in how we define "Boom". I was born in 1950 so remember sonic boom before it was outlawed over our homes. You can get a 100hz freq to boom within a room...20hz?...naaah, it would take a huge amount of power.

I guess the other place we differ is on how X-over effects room modes. I have done hundreds of tests using many configurations...over-all measurements as a complete system (speakers+sub) can change drasticly with only a change of x-over settings.

At this time my front subs are 25 ft apart and located at around the ceiling/floor null-point, (Supertowers are upside down) and in the corners in other words. What do you think Rives would think of that!...gotta love those measurements and go with what works after all.

Dave

Eldartford

Our systems are somewhat similar...planers, three subs with six large drivers. I suspect the difference that I measure and you don't are related to X-over and mains settings.

Sounds like you run the Maggies full-range thus always the same at their location with the only change being at the subs location.

I use fixed points which changes output freq levels at both locations having greater effect on measurement..at least in my findings.

My Duetta Sig's have an in-room rise of 2db at 30hz and then a roll-off to 25hz...the lowest setting on my X-over is 35hz and the blend between the mains (run full-range) with 35hz X-over to the sub is a little much in my room...a new X-over {maybe one of the digitals) with more choice of filter would probably benefit.

At this point, I x-over at 50hz with 6db slope.

Well, I guess I have gone far off topic...sorry

Dave