Understanding Coupling/Decoupling - with particular reference to loudspeakers

[JackD201]

I think it's the nature of high-end anything. Hate to sound all new-agey but there's a lot to be said for finding balance and harmony taking into account and accepting weaknesses. I bet you know a lot of really strong athletes that have gotten injured because they neglected development of certain muscle groups while chasing certain performance targets huh Myles?

 

[garylkoh]

I think it's the nature of high-end anything. Hate to sound all new-agey but there's a lot to be said for finding balance and harmony taking into account and accepting weaknesses.

Absolutely! The yin and yang of hi-end anything

In much of what I do in design, I have to accept that what may have been seen as a weakness might turn out to be a strength when you look at it another way. As an example, on topic, trying to couple tightly is difficult, and if not perfected then increases the resonance frequency often into the audio frequencies, whereas loosely coupling takes the resonance frequency down, and you can more easily get it to below 10Hz.

 

[sasully]

How about some graphics of high-resolution in-room measurements demonstrating these presumed effects? Seems that at least some of them are predictable and should be measurable.

 

[garylkoh]

Unfortunately, then that would get this thread into another of those what's audible vs what's measurable never-ending stories.

If some of these ideas make your system sound better to you, then I'm happy for you. If they don't, then consign it to the "inaudible tweaks bin". However, techniques for coupling/decoupling loudspeakers are very loudspeaker/floor specific. If it doesn't work on your current pair of loudspeakers, it may work on your next pair.

 

[Phelonious Ponk]

Gary, surely if you've built coupling or isolating into your speaker systems you've measured the effects? Besides, nothing ends that what's audible vs what's measureable never-ending debates more effectively than solid evidence.

Tim

 

[garylkoh]

Gary, surely if you've built coupling or isolating into your speaker systems you've measured the effects? Besides, nothing ends that what's audible vs what's measureable never-ending debates more effectively than solid evidence.

Tim

Yes, I measured while doing the design to optimize. But I didn't take high resolution screenshots, and the changes were more audible than measurable and there will be those who will argue that the measurements shown will not be audible. Even if I were to post the measurements, the problem is that you can't fight an opinion even with solid evidence.

 

[Phelonious Ponk]

Yes, I measured while doing the design to optimize. But I didn't take high resolution screenshots, and the changes were more audible than measurable and there will be those who will argue that the measurements shown will not be audible. Even if I were to post the measurements, the problem is that you can't fight an opinion even with solid evidence.

True that. I'm skeptical enough to question some of the flooby dust claims around coupling/decoupling. Like everything audiophile, in the ears of the right enthusiast, the subtlest of effects becomes the paradigm-busting shift from sterile reproduction to glorious music, with (always) an expansion of soundstage. But even with that skepticism on the table coupling or decoupling speakers from their most direct interaction with the room is bound to have an impact.

Tim

 

[rbbert]

Gary, I would like to post some of your analysis at other audiophile websites (with proper and grateful attribution, of course). Would that be acceptable to you?

 

[NorthStar]

Gary & Tim,

Also, not two rooms measure the same.
So I do agree with Gary's comment above regarding room's measurements and all that Jazz...

Cheers

 

[Phelonious Ponk]

Gary & Tim,

Also, not two rooms measure the same.
So I do agree with Gary's comment above regarding room's measurements and all that Jazz...

Cheers

Absolutely true about rooms. Couple a pair of speakers to a raised wood floor. Couple the same pair of speakers to a concrete slab. They will sound different. And it will be measurable. And measuring could be very useful. Most people in America have suspended wood subflooring, even if there is just carpet on top. Measure coupling to enough rooms with such floors and a patter might emerge. One might get a very good idea of what coupling to such a floor will do to FR. My guess is there are some repeatable patterns. I think it would be very useful to know what they are, particularly to speaker designers.

Or maybe not. Or maybe it's just a lot more fun to play with spikes and blocks and blue tack until you hear what you like. Different strokes and all that.

Tim

 

[mep]

I'm trying to figure out the point to this thread. What do you want the measurements to tell you Tim? That it matters if you spike your speakers to concrete or wood floors or it doesn't make any difference and you might as well set them right on whatever floor you have?

 

[NorthStar]

Absolutely true about rooms. Couple a pair of speakers to a raised wood floor. Couple the same pair of speakers to a concrete slab. They will sound different. And it will be measurable. And measuring could be very useful. Most people in America have suspended wood subflooring, even if there is just carpet on top. Measure coupling to enough rooms with such floors and a patter might emerge. One might get a very good idea of what coupling to such a floor will do to FR. My guess is there are some repeatable patterns. I think it would be very useful to know what they are, particularly to speaker designers.

Or maybe not. Or maybe it's just a lot more fun to play with spikes and blocks and blue tack until you hear what you like. Different strokes and all that.



Tim

...Good sense of humor Tim, mixed with science, and positive experimental suggestion!
Me like.

 

[fas42]

I think it's the nature of high-end anything. Hate to sound all new-agey but there's a lot to be said for finding balance and harmony taking into account and accepting weaknesses.

Gary also emphasises that acknowledging balance is a good thing. I, being a persistent and hard to satisfy bastard, hate things almost being right, I always have to push things a bit further. So, my findings that tight coupling has a big plus of getting much closer to "live" sound, but a corresponding big minus that every problem area is blatantly exposed has forced me to work harder on correcting the system deficiencies, rather than taking the easy way out of softening the coupling ...

Frank

 

[fas42]

Gary, surely if you've built coupling or isolating into your speaker systems you've measured the effects? Besides, nothing ends that what's audible vs what's measureable never-ending debates more effectively than solid evidence.

Tim

Art Noxon's MATT test is a pretty obvious candidate for something like this ...

Frank

 

[JackD201]

The biggest hurdle is actually knowing what IS right. I said I love Blu for monitors on stands for the simple reason that it sure as heck sounds better than MDF on a metal plate. It keeps your speakers from falling off with minor brushes or nudges. It is also cheap. That is not a bad combination for an ordinary user.

Gary mentions many different methods that are speaker dependent and if we are to look at it from an enthusiast standpoint, I would have to say that I am in full agreement with him. There's no way ball/cup or elbow types will work for your speakers. Your speakers are just too light and probably don't have the surface area to even consider using the minimum number of 3 bearings. That lightness is undoubtedly helped along by what Gary refers to as mass loading your speakers via coupling.

My main loudpeakers have MT modules that weigh over a hundred pounds. Clearly Blu-tak isn't even practical for this application. Instead 6 heavy rubber pucks are used. The modules don't have drivers with long excursions so the pucks don't have to deal with much lateral energy. The entire loudspeaker is on ball casters and have now settled into their own self made little cups on my engineered wood floor. Not quite bearings in a cup but the closest one would get to it. The total weight of the loudspeakers now with the added stone internal bracing is around 400lbs. They aren't going to be rolling around unless I push them with quite a bit of effort. Still it is a whole lot less effort to position them than calling in the national guard to make micro positioning changes. The floor under the speakers have tracks from moving them and dents where they've settled. This isn't a big deal for me at all. First I don't see them and second if they need changing, I have the extra planks and removal and installation is easy.

Now compare that to the 2-way monitors I've been playing with for the last two months. They weigh in at 27 pounds and has usable bass (in-room) into the 30s. I have them on 60lb solid wood stands. They aren't cheap either so the number one consideration is that they don't go crashing on the REAL wood floors that will cost even more than the loudspeakers to fix even if I would be lucky enough to find the matching lumber. Second would be to just keep the speakers as steady as possible. At only 27lbs and with excursion ball/cups are out. Enter Blu Tak. Cheap, safe, steady. Now is it best? I don't know. I'm liking the sound. Imaging is very solid, distortion is very low played at loud but sane levels. At this point where the system is delivering the goods already, I find myself making micro-adjustments elsewhere. Finding out what to put between these monitors and stands is very low on my priority.

 

[garylkoh]

True that. I'm skeptical enough to question some of the flooby dust claims around coupling/decoupling. Like everything audiophile, in the ears of the right enthusiast, the subtlest of effects becomes the paradigm-busting shift from sterile reproduction to glorious music, with (always) an expansion of soundstage.

Tim, of course! Some people will even hear the difference between blu-tac and yellow-tac. I think that if it's what's best for the individual, then that's the right solution without someone telling him that it's flooby dust and his imagination.

 

[garylkoh]

Gary, I would like to post some of your analysis at other audiophile websites (with proper and grateful attribution, of course). Would that be acceptable to you?

I would be scared to do that because I'll have no time to monitor those other websites and comments there. I have a tough enough time keeping up with the comments here on WBF!!

 

[NorthStar]

Good Post (#55) just above Jack!

 

[fas42]

The biggest hurdle is actually knowing what IS right.

One thing that I do know, for myself, over the many years of fooling with this crazy hobby, is what's right. And that's what allows all recordings to give of their best: as soon as a "bad" recording sounds bad then I know it's not right. It's as simple as that and has been that way for 25 or so years. At the risk of disturbing Tim in his lair, it can also be assessed by there being a universal sweet spot, completely invisible speakers.

There's no way ball/cup or elbow types will work for your speakers. Your speakers are just too light and probably don't have the surface area to even consider using the minimum number of 3 bearings. That lightness is undoubtedly helped along by what Gary refers to as mass loading your speakers via coupling.

My main loudpeakers have MT modules that weigh over a hundred pounds. Clearly Blu-tak isn't even practical for this application. Instead 6 heavy rubber pucks are used. The modules don't have drivers with long excursions so the pucks don't have to deal with much lateral energy. The entire loudspeaker is on ball casters and have now settled into their own self made little cups on my engineered wood floor. Not quite bearings in a cup but the closest one would get to it. The total weight of the loudspeakers now with the added stone internal bracing is around 400lbs. They aren't going to be rolling around unless I push them with quite a bit of effort.

I would still be tempted to use Blu-Tack or something even more heavy duty. I made a habit of surreptitiously pushing gently against the top of supposedly immensely heavy and stable speakers, and every time thought, this was a joke. There was hardly any resistance to that lateral force and the sound of that speaker, if I heard it, matched that impression. My reference is the sensation of putting gentle pressure against the top of a safe, and feeling that absolutely nothing could move this.

Imaging is very solid, distortion is very low played at loud but sane levels

That's exactly what I would expect. The addition I would make is that when I experimented with mass loading, the heavier I made the effective weight, the louder I could go. To the point where the 200W amplifier was very clearly letting go ...

Frank

 

[garylkoh]

Good Post (#55) just above Jack!

+1