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Bass reinforcement for very large room

My main system resides in the great room of our open-concept house - essentially a 30x30 open area (entryway, family room, dining room, kitchen) with 15' ceilings.

My second system resides in the 11x15 master bedroom.

Recently I have become especially aware at how much better the much more modest system in the BR sounds - it is weighty and more authoritative. Why? Because no matter what sort of main speakers I use in the large room, it seems they cannot produce enough space for that very large space. In contrast, the BR speakers, with smaller drivers and lesser bass extension, pressurize the room and fill it with sound so easily.

The speakers (now) are Hyperion 938s. They are a quite-capable full-range speaker, solid to the low 30s or so. (The 'lack of weight' that plagues the great room is something that surely extents all the way up to the upper-bass, probably 125-150 Hz, so the speakers' extension is really not too vital. IOW, if they were flat to 20 Hz it wouldn't be much different.)

I am thinking subs are the only/best way to cure this. I could use some kind of EQ - but that would undoubtedly result in great driver excursion and an extreme load on my (modestly-powered) amplifiers. I think I need a lot more driver *area*. In other words, in this case there's no replacement for displacement. (And, by the way, I am no 'bass fiend'.)

I've had subs before. I don't like them because it seems they just never integrate *perfectly*. Especially if they must be relied on all the way up to 100 Hz or higher (which is something I've never even tried).

I don't really have any questions per se and am really just ruminating out loud, but if anyone has any thoughts to share, be my guest. (Moving might be my best bet.)
paulfolbrecht
paulfolbrecht OP
586 posts
 
Buconero117 - New speakers? YOU'RE THE DEVIL! YOU'RE THE DEVIL!!!!

Kijanki - have tried 200W SS and digital amps - tube amps have more & better bass.

Turns out there ARE bass nodes - there is a spot over in the dining area that has mucho bass response. Damn!

Well, there's one REL sub on the way already. We'll see what can be done. Neither the listening position nor the speakers can really be moved.
kijanki's avatar
kijanki
3,575 posts
 
I'm not sure you need two subs. Scheme with two subs is often used when you need to equalize bass in large listening area (home theater with many rows of seats). For fixed listening position one sub properly placed should be ok especially one that can equalize (with microphone) itself like JL Audio Fathom F113.

Do you still like your HPS-938? There is some "ease" and something very relaxing in their presentation but they are also very snappy and dynamic at the same time.
kijanki's avatar
kijanki
3,575 posts
 
One more thought - have you tried to rotate bass units? it shouldn't affect imagining since crossover cuts at 220Hz. I assume you have standing wave along the room. Directing bass units inward toward sidewalls might change it (but it looks ugly). Your room amplifies 20Hz (1150/30/2) - too low to get any audible benefit. Nodes in the room will move with frequency and if you have strong nodes then bass is perhaps uneven as well. Bipolar speakers don't make nodes in the room. You can get the same effect firing two bass units in opposite directions - standing waves will cancel but it will look very weird.
drew_eckhardt
394 posts
 
12-22-09: Kijanki writes
> Bipolar speakers don't make nodes in the room.

Bipolar speakers most definitely stimulate room modes - I measured over 10dB peak around 70Hz in one room with a pair of Definitive BP8s.

In the modal region conventional speakers are omnidirectional (a 100Hz wave is 11' long and wraps around any speaker you can fit in your living room like it wasn't there). Apart from the force cancellation you get which reduces structure borne vibrations having the drivers on opposite sides instead of one surface doesn't make a difference you can't get by moving a box with drivers on one side.

Dipoles with the front and back waves 180 degrees out of phase do interact differently, producing measurably weaker height and width modes although you need to equalize at 6dB/octave and use multiples to get sufficient head room (with 15" separating the drivers, at 40Hz it takes 4 drivers to play as loud as a single driver in a closed box).
kijanki's avatar
kijanki
3,575 posts
 
Drew - Are you talking about peaks and valleys caused by standing waves or just room resonances? I read that Planars and Electrostats are praised for the lack of nodes/standing waves - I guess this is the 180 degree back wave type. I never had this type of speaker in my room.
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