[jimdgoulding]

What would be a listeners room dimensions, Jim?  Where are said speakers and in relation to walls and seat?  Sometimes its a room thing.  This info might be helpful.

[jimdgoulding]

Dupilcate.  Kindly excuse.

[Folsom]

I am curious what speakers he happens to have.

Just to point out I only point stereo subwoofers at the wall they are near (right and left) and tilted up a few degrees (like if you put a beer sideways underneath the front, maybe bigger depending on box height). They end up being too close to have wave lengths the same distance. But I only at max let them play up to 150hz, if not lower depending on the mated speakers. I read about this placement on mapleshade's website at some point I believe. I found it to do the absolute most for stereo imaging, overall balance on volume, and enjoyable resonation. It seems weird but what can I say, it made bass guitars, uprights, and drum kicks rather amazing. In fact amazing in ways that no small driver can reproduce (that I have heard to date, even in very expensive stereoes) in a general speaker that supposedly plays into that range. Oh and lastly, I made my boxes about 3.5ft tall or so... (hence 8ft to ceiling was no longer true).

What is really going on with that placement that eliminates any wave length problem I encountered with other positions? I have no idea, it just works. Pointing the subwoofers at the listener wall resulted in massive losses of certain frequencies and not others. The same thing happened aiming at the back wall. 

Scotty, I don't remember where the -3db is at for Horn Shoppe Horn's. When I used stereo subwoofers it was at about 18hz.

I'm talking about lowering the dampening factor on full ranges. Read up on the FirstWatt F1 and how it can only be used on OB and Horns for this reason. Lower dampening actually exerts a lot more control over the woofer. Increasing it allows the natural built in characteristics of woofer to show greater. A typical driver in a sealed box will beat itself to death hooked up to an F1. I'm not too familiar with servo-controlled sub-woofers. They probably fight the fact that they have high dampening factor with sheer power, but by doing so it prevents destroying the subwoofer.

Room response isn't the same thing as first achieving the best possible bass articulation. I recommend finding good bass articulation first and foremost.

[*Scotty*]

Having flat bass response in the listening room wouldn't be a bad place to start from. By itself it won't insure good bass reproduction accuracy anymore than flat response over the entire frequency spectrum guarantees High Fidelity reproduction of the music waveform as whole. Both are merely places to start from. The bare minimum entrance fee as it were.
DoS said

I am curious what speakers he happens to have.

I am lost here, whose speakers are you referring to.
Scotty

[medium jim]

What would be a listeners room dimensions, Jim?  Where are said speakers and in relation to walls and seat?  Sometimes its a room thing.  This info might be helpful.

Nothing specific, just a general inquiry that stemmed from a response in another thread.  With subwoofers, you can strategically place them and or adjust the crossover(s). With full range floor standers, you have less options to work with.

Maybe those with specific issues will post and we can work from what they post. Nevertheless, I feel the issue warrants discussion as many don't employ subs.

Jim

[Folsom]

I thought Jim was dealing with an actual issue...

[bpape]

Just remember that most of the discussion so far has been geared around how to get a smoother frequency response.  EQ, Multiple subs, etc. will not address excessive decay times.  You could have +/-1 db response and if 50Hz is ringing for 2 seconds before dropping 30-40db (not as unusual as you think.....) , it still needs work, is still masking imaging cues - harmonic structures - microdynamics - etc.

And don't go off the deep end and say I'm wanting an overdamped room.  I don't.  I want a PROPERLY damped room and concentrating on the ranges that need it.   That's usually then bottom end.

Bryan

[THROWBACK]

OK, Brian--that makes a lot of sense. But how does one identify a 50Hz (or any other specific) ringing tone and how does one treat it without overkilling everything else?

[medium jim]

OK, Brian--that makes a lot of sense. But how does one identify a 50Hz (or any other specific) ringing tone and how does one treat it without overkilling everything else?

Excellent question!

Jim

[stevenkelby]

But how does one identify a 50Hz (or any other specific) ringing tone

Waterfall graph.

http://gikacoustics.com/room-eq-wizard-tutorial/

and how does one treat it without overkilling everything else?

Tuned Membrane Bass Traps

http://gikacoustics.com/product-category/tuned-membrane-bass-traps/

 

[SteveFord]

MediumJim suggested that I post this chart to demonstrate a different way to tame too much bass.
This chart is for the deHavilland UltraVerve 3 when mated up with VTL 300 DeLuxe monoblocks:

Cap                  100 hz                       50 hz                     30 hz
.01 uf               -4 db                         -8 db                      - 12 db
.02 uf               -1.2 db                      -4 db                       - 7 db
.033 uf              -.07db                      -2 db                       -4 db
.047 uf              -.02 db                     -1 db                       -2 db

This shows the difference from the stock preamp coupling caps which are 1.5 uf.
You can go the opposite way, too, of course.
Calculations courtesy of Kara Chaffee at deHavilland.

[stevenkelby]

Well that doesn't control ringing or reflections at all and you lose all bass below the roll off frequency, even where you might not have enough to begin with, in nulls.

Still, I'm sure in some situations that would be just what's needed

[SteveFord]

There are no tone contols on just about everything, nowadays.
I'm not sure if that's a step forwards, backwards or sideways.

[stevenkelby]

I guess there is no golden answer, depends on the situation. I sometimes adjust the output level of my subs based on personal preference for different music/movies, the time of day, listening volume etc, regardless of what the measurements may say

[bpape]

Agreed. As in most cases, there is no one single answer. A combination of careful placement, multiple subs, and judicious use of treatment allows fine tuning of many parameters that no one of them by themselves can.

Bryan

[Guidof]

There are no tone contols on just about everything, nowadays.
I'm not sure if that's a step forwards, backwards or sideways.

A step backwards, in my view. One of the useful features of the DSPeaker Anti Mode (in additio to room correction) is the set of house and tilt curves, in effect flexible tone controls in which the user can set both the pivot point and the degree of boost or cut. I found these to be very useful not only to fine tune the bass but also the treble. Because what we're looking for is tonal balance, controlling both ends of the frequency spectrum yields significant dividends, I think.

Guido F.

[rodge827]

A step backwards, in my view. One of the useful features of the DSPeaker Anti Mode (in additio to room correction) is the set of house and tilt curves, in effect flexible tone controls in which the user can set both the pivot point and the degree of boost or cut. I found these to be very useful not only to fine tune the bass but also the treble. Because what we're looking for is tonal balance, controlling both ends of the frequency spectrum yields significant dividends, I think.

Guido F.

+1