Bad setup, bad room, or sensitive ears? Subs are just never from the "same cloth"!

[twelti]

If you assume a completely linear system, then I agree with the waves on an ocean analogy. It is simply the principle of superposition. I also wonder how much the sub actually does move the ESL panel in practice. If the sub is truly an omni source and the ESL panel directly above it, the pressure on the back would be the same as in front and no movement. Of course a sub is not a perfect point source, and reality is a bit more complex. If the sub did manage to move the panel enough, I wonder if there could be some nonlinearity (modulation effect) produced?

As for mono summing with dipole response, I think of it as a pressure source and a velocity source (respectively). The way that they couple into the room will be compementary. For any given mode, the pressure source (standard sub) will couple most efficiently to pressure maxima in the room. The velocity source (dipole) will couple most efficiently to the velocity maxima in the room. THe pressure maxima correspond to antinodes (peaks) in the spatial response of the room, and the velocity maxima correspond to nodes (dips) in the spatial resposne of the room. The velocity source is complicated by the fact that it will depend on the orientation of the source in the room. Anyway, that means the way the sub and ESL panel couple to the room (and thus is transfered to the listener) would be guarenteed to be different, since one will be coupling to pressure maxima and one to velocity maxima (mutually exclusive).

This might sound complicated, but in real life it's proably even more complicated! The above is probalby a gross simplification.

[FrantzM]

Twelti

I understand it can get real complicated down there but in the end are these diferences in coupling really audible when combining an ESL or other Falt Panel with subwoofers. I was of this opinion until I carefully set up my Magnepan 20.1 with three cone subwoofers.. My system never sounded or measured better in the bass .. Biases of expectations are there .. There are so many myths in the audiophile mindscape .. For many there will never be any way that a "slow" cone could ever keep up with a "fast" or "quick" panel.. This is even more difficult to dispel than we would think .. if on were to mate an ESL with no bass with a good subs system, the added bass could well be described by the ESL-is-faster believer in negative terms ... The bass would be heard .. No way to hide it ... So ...

[fishnchips]

For many there will never be any way that a "slow" cone could ever keep up with a "fast" or "quick" panel

"Fastness" or "slowness" can be measured. One may anthropomorphically equate light with fast and heavy with slow, but the fact of the matter remains that Sebastian Vettel's heavy monocoque will always be faster than a toddler's light plastic tricycle - even if one switches drivers. There is more to acceleration than mass, and a certain Sir Isaac wrote about it several centuries ago. In the case of "slow cones", the limiting factor in acceleration is, more often than not, a low-pass crossover.

[mjaudio]

The quality of a subwoofer is only one part of the equation. The setup is probably the most important portion of the "integration" scheme. I brought up the subject here:

http://www.whatsbestforum.com/showth...-Relationships

and the ensuing discussion quickly showed how complex seamless integration of a sub (or multiples) can be. Most folks don't take the time and effort to accomplish good integration IMO.

Lee

Right off the bat Lee gave the best answer first.

It's easy to make a great subwoofer sound horrible when it's not properly integrated which can be one of the hardest things to do. It's probably more proper to refer to subwoofers as bass systems since any full range speaker has a bass system. Someone referred to the bass of the Wilson Maxx speakers but if you cut away the bass portion of that cabinet and located it separately from the mid/tweeter section it would effectively be a subwoofer.

There is absolutely no reason a properly designed subwoofer can't be integrated into speaker set-up as well if not better than a full range speaker. It just proper takes knowledge of how the sub reacts to the room and speakers through placement, proper crossover, phase, polarity and EQ never hurt anyone.

[FrantzM]

"Fastness" or "slowness" can be measured. One may anthropomorphically equate light with fast and heavy with slow, but the fact of the matter remains that Sebastian Vettel's heavy monocoque will always be faster than a toddler's light plastic tricycle - even if one switches drivers. There is more to acceleration than mass, and a certain Sir Isaac wrote about it several centuries ago. In the case of "slow cones", the limiting factor in acceleration is, more often than not, a low-pass crossover.

fish

Care to elaborate, especially the last part... " the limiting factor in acceleration being the "low-pass crossover" ????

[fishnchips]

This is analog filter theory, it is covered extensively in many textbooks.

[twelti]

I am going to start a thread on "fast" and "slow" subwoofers very soon. I would like to put it to bed.

[diggo]

To me, the biggest issues are not the subs or drivers. If the room is not properly treated, moving a sub even by a few inches can make a dramatic difference to the sound. If the room is not properly treated, room resonances mask the actual sound emitting from the sub. If the subs are located away from the walls, SBIR is a big problem. If the system crossovers arent set optimally, SBIR from the mains is also a big factor at low frequencies. If all the preceding problems arent properly mitigated, the issues of one particular sub versus another (fast, slow, whatever) are almost irrelevant.

Treating the room isnt sexy, so most attempts to do it are pathetically poor, particularly among audiophiles. People prefer to spend money on sexy gear, not rooms and room treatments. Most have no idea of the requirements to properly treat a room. Many make a token gesture, typically without any appreciation of the true nature of the problem. Their listening experiences are then filtered through the prism of their room. It's no wonder very few are satisfied with subs and struggle to describe the results.

Sean

[FrantzM]

To me, the biggest issues are not the subs or drivers. If the room is not properly treated, moving a sub even by a few inches can make a dramatic difference to the sound. If the room is not properly treated, room resonances mask the actual sound emitting from the sub. If the subs are located away from the walls, SBIR is a big problem. If the system crossovers arent set optimally, SBIR from the mains is also a big factor at low frequencies. If all the preceding problems arent properly mitigated, the issues of one particular sub versus another (fast, slow, whatever) are almost irrelevant.

Treating the room isnt sexy, so most attempts to do it are pathetically poor, particularly among audiophiles. People prefer to spend money on sexy gear, not rooms and room treatments. Most have no idea of the requirements to properly treat a room. Many make a token gesture, typically without any appreciation of the true nature of the problem. Their listening experiences are then filtered through the prism of their room. It's no wonder very few are satisfied with subs and struggle to describe the results.

Sean

Welcome to the WBF. Great (first) post. I would add that even in a well treated room moving the subs a few inches may result in noticeable change in sound/performance. Else I agree with you.

[twelti]

Treating the room isnt sexy, so most attempts to do it are pathetically poor, particularly among audiophiles. People prefer to spend money on sexy gear, not rooms and room treatments. Sean

All true. Plus, room treatments for low frequency problems aren't cheap by any means.