[lonewolfny42]

Mike....did some surfing....

Unfortunately, I live in a small flat (the Helicons need plenty of space) and as a result the lower region suffers from resonances around the area of 100 Hz. However, I plan to move soon to a new, bigger house and this might solve the problem. Another workaround could be the covering of one of the portholes - I plan to experiment on this soon.

[lonewolfny42]

http://www.dali.dk/admin/filer/H8005starWHF0506.pdf

[Wind Chaser]

Center of the "any" point in the room is not a good place to be.

Moving just a few inches off center in any direction will produce markedly better results.

That's supposed to be true in regards to a perfectly symmetrical room, however all my rooms have been quite irregular.  Experiment with an open mind and listen for what sounds best.  Bass isn't my top priority.  There's no substitute for a big believable sound stage.  Spreading the speakers as wide apart as possible with plenty of room around them is what works best for my liking.

[bpape]

Agreed.  Every room is different.  His room is basically rectangular - especially in the end he's sitting.  He's sitting between 6 very large parallel surfaces.  Yes - the tangential and oblique modes will be different as well as some overlap/cancellations from the little bumpout but the axials will be pretty much where predicted.

Getting good bass in a room is a combination of so many things including speaker placment with regard to the listener, with regard to the walls behind, with regard to the walls behind them, where the seat is, etc.  I know via discussions on another forum that he's played some with these things with a couple of different speakers and not had a lot of luck. 

Normally my recommended process is:

- remove all treatments from the room. 
- Place 1 speaker in a room corner and move around until you find a couple places that yield relatively even bass response.
- Place the speaker in the opposite corner on the same end and repeat.  See where you find overlap with positioning from what you did before.
- Place the seat there to start with.
- Set up the speakers so that the distance beside from centerline and behind from front face is not the same - nor are they the same as the distance from your ear to the wall behind you nor a multiple of it.

That's usually a decent starting point.  Tweak based on specific speaker requirements (Maggies different than Salks, etc.) and to suit your imaging preferences.  Listen what happens when you move the speakers toward or away from the side or front boundary and find the best balance. 

Then, walk around the room and see where bass is building up or is weak.  Hit the buildups first with treatment.  If you find weak spots, look where you are and think about what modal issues or distances might be causing it.    Finding peaks and nulls in odd places are good indications of where tangential and/or oblique modes may be interacting and worsening borderline axial issues. 

Sometimes you just get into a situation where you can't get good imaging and good bass response at the same time.  This is when a good monitor/subwoofer combination really shines as you CAN move the bass to where it's best and leave the mains where you get the imaging you want.

I'd be very interested to see a measurement set from the room and see where the issues really are.

Bryan

[ooheadsoo]

You know, my room has roughly similar dimensions (14x16.6 with irregular cavities) and I also have horribly deficient bass, despite moderate bass trapping.  Adding a subwoofer does not help the situation, at all.  I'd be interested in what you work out.  The best I've managed to do is move my speakers towards the corners of the room.  With the trapping, the bass response is smooth and more elevated - but still weak.  The middle of the baffle is roughly 3' from the front and 2.25' from the sides.  Since my current speakers have controlled directivity, I'm not too worried about the higher freqs. reflecting from the sides.  I would move them even closer to the corners, but I'm currently out of room.

[Duke]

Sounds like quite the challenging room, mca!  Unfortunatley, I don't see an obvious reason why your room would be so bass-shy.  The only significant openings are the doors, right?  Does closing the doors make much difference? 

When you had the Gallo 3.1s, did you try the booster amp on the woofer's second voice coil? 

Have you tried subwoofers? 

ooheadsoo, can you go into a bit more detail about your experience with subwoofers in your bass-challenged room?  In what way did they "not help"? 

Thanks!

Duke

[ooheadsoo]

Well, in my experience, and granted I don't have many placement options (actually, after I dropped this beast of a subwoofer down the corner pinned between an old post ww2 style steel desk and a bed, there was no where it was moving anywhere else,) no amount of adjustment and phase shift could assist in filling in the nulls inherent to the room.  Perhaps the position of the sub is such that it doesn't help my situation.  However, going by the general placement guides, it's in a pretty decent location, and there're really no more placement choices available.  Nevertheless, sub or not, a frequency response sweep shows a general bass depression in the room from 200hz on down.  With test tones, it's easy to hear/feel the cancellations at higher SPLs.  As you turn up the volume, you can feel some pressure shifts, but all you really hear is higher order distortion.

I think that the only time I was ever happy with the bass quantity in my room was when I had a Hsu STF-2 sitting plumb in the corner.  It was really excellent for the price, perhaps excellent, period, and they weren't as well known back then, so I sold it at a relatively stiff loss.  I often wish I hadn't sold it. 

[Duke]

I appreciate your replying, ooheadsoo.

Yeah I was a Hsu dealer back in the days when they sold through dealers.  Very good products.

One of my unorthodox ideas about subwoofers (borrowed from Earl Geddes) is to use a bunch of smaller ones spread somewhat asymmetrically around the room, rather than one giant ubersub.  The idea is that each little sub generates a unique peak-and-dip pattern at the listening position, and the net combination of their non-identical patterns is smoother than any single sub would have been.  So far it seems to work well, but I haven't had a chance to try it in a room that's like a giant sinkhole for bass. 

Were you unable to turn the gain up high enough on the sub to get decent bass loudness?  When you say "As you turn the volume up... all you can really hear is higher order distortion", are you talking about harmonic distortion (doubling) from the subwoofer?  I'm a bit confused by that part of your description.

Thanks,

Duke

[ooheadsoo]

I've read Dr. Geddes white paper on the subject - while interesting, it's cost prohibitive, for me.  I also don't have room for multiple subs, and floating them in the air, as Dr. Geddes suggests, just won't fly.  If anything, I might try 2 mono subs at opposing ends of the room, per the Harmon white paper out there, but that won't be any time soon.

Yes, I believe it is primarily harmonic distortion that I can hear, possibly non harmonic, as well.  There's plenty of room on the gain knob, but it basically sounds like 2 speakers playing the same signal out of phase, where the cancellation isn't perfect.

I think we should leave my room out of it, for now, since I haven't come up with any solutions, so mca can get more help.  I appreciate your asking, though, Duke.

[mca]

I built a monster sub hoping for a little better HT experience, except for a little added low end, you would never even know it was there. I've wanted to try dual subs for music, but just don't have the funds or will to tackle such a complicated setup.

Anyone local interested in this beast?

[mca]

I've had several PM's suggesting I try taking some of the panels out of my room as I may be doing more harm than good. I tried taking all the traps out of the corners and it did improve bass a wee bit. I am going to try removing the rest later this week and see (or hear) what happens.

I am really hoping the open baffle design of the Emerald Physics speakers works well with my room as I just bought a pair in a very good deal on Audiogon 

[mca]

The only significant openings are the doors, right?  Does closing the doors make much difference?

When you had the Gallo 3.1s, did you try the booster amp on the woofer's second voice coil? 

Just one door, the one in the back of the room is for the electrical panel. Closing it does not make any difference. I did use the Gallo bass amp when I had the 3.1s.

[fly_fish_nz]

Have you tried a setup along a diagonal of the room?  I've tried such a setup in the past after reading about Merlin, DeHavilland, Decware, and others using them is small squarish rooms at shows, and was very impressed with the results.   There is a pic of the set up in this thread: http://www.audioasylum.com/scripts/t.pl?f=speakers&m=184837

[mca]

Have you tried a setup along a diagonal of the room?

I have, along with setting up on the long wall with no real improvements.

[Wind Chaser]

Interesting problem.  What kind of music do you listen to?