Interesting - please let us know. I would also check with Sistrum if their stands would work with the downward firing woofer.
Understanding Coupling/Decoupling - with particular reference to loudspeakers
- Thread starter garylkoh
- Start date
Actually one of the music lovers in the Atlanta area guided me in this direction. He was pretty emphatic to the point of stating that if you don't buy the stands, don't buy the speakers. Now the speakers sound great, kind of a hybrid full range with a tweeter w/single order crossover and a pair of full range drivers.
When I visited Jim Smith he commented that I could get pretty close to the performance he's getting from his Tannoys. Hope so, his system is outstanding, as you may imagine.
Regardless, thanks for the article, first well thought out info on the subject I've come across.
When I visited Jim Smith he commented that I could get pretty close to the performance he's getting from his Tannoys. Hope so, his system is outstanding, as you may imagine.
Regardless, thanks for the article, first well thought out info on the subject I've come across.
Hello, Gary. I hope you are enjoying your weekend. 
I had a good friend of mine ask a question on another forum I thought to be of high interest. I touches on the topic here so I figured I would ask your thoughts on the subject.
I am actually intrigued by this question, as I have always pondered this whilst listening but never got around to asking. In my particular case, it won't be for a bookshelf or mains but for the subs I have that I set on extremely heavy stands. IME, this yields a better overall presentation, spatial locational cues, impact and overall realism versus placing the subs on the floor. My subs are placed currently with the woofer at the tweeter/ear level. If you would be so kind, would you please mind sharing your thoughts on this subject?
Tom
I had a good friend of mine ask a question on another forum I thought to be of high interest. I touches on the topic here so I figured I would ask your thoughts on the subject.F1nut said:
I am actually intrigued by this question, as I have always pondered this whilst listening but never got around to asking. In my particular case, it won't be for a bookshelf or mains but for the subs I have that I set on extremely heavy stands. IME, this yields a better overall presentation, spatial locational cues, impact and overall realism versus placing the subs on the floor. My subs are placed currently with the woofer at the tweeter/ear level. If you would be so kind, would you please mind sharing your thoughts on this subject?
Tom
Hi Tom,
I enjoyed my weekend...... all of it except the last 2 minutes of the Superbowl. It's only the second football game I've ever watched in my life, and even as a rookie I thought that with 1 yard to go, and that big guy that we have (Lynch) just give him the ball and let him power through..... But then again, it's only the second football game I've ever watched so what do I know?
This topic was very briefly covered in one of the early posts:
http://www.whatsbestforum.com/showt...-to-loudspeakers&p=71837&viewfull=1#post71837
It really depends on the design of the speaker stand. In many cases, the stand isn't massive enough and well-coupled enough to be regarded as part of the Earth, and isn't light enough that you would couple it to the speaker and make it part of the speaker. In both cases, it then the interaction of the stand makes vector forces extremely complex. As the center of gravity of the stand would be below the speaker, the stand actually rocks in the opposite direction of the speaker. Then, couplers, decouplers, sand, etc. change this interaction and all bets are off. I'll try to get a diagram done and post later.
I enjoyed my weekend...... all of it except the last 2 minutes of the Superbowl. It's only the second football game I've ever watched in my life, and even as a rookie I thought that with 1 yard to go, and that big guy that we have (Lynch) just give him the ball and let him power through..... But then again, it's only the second football game I've ever watched so what do I know?
This topic was very briefly covered in one of the early posts:
http://www.whatsbestforum.com/showt...-to-loudspeakers&p=71837&viewfull=1#post71837
It really depends on the design of the speaker stand. In many cases, the stand isn't massive enough and well-coupled enough to be regarded as part of the Earth, and isn't light enough that you would couple it to the speaker and make it part of the speaker. In both cases, it then the interaction of the stand makes vector forces extremely complex. As the center of gravity of the stand would be below the speaker, the stand actually rocks in the opposite direction of the speaker. Then, couplers, decouplers, sand, etc. change this interaction and all bets are off. I'll try to get a diagram done and post later.
Thank you, Gary. We *might* try it both ways to see what sounds better. Him with a monitor/bookie and me with my front firing subs. The subs probably weigh in at 120 pounds a pop and the stands (with spikes on carpet) have got to weigh close to 175 or more pounds.
That game was crazy in the last two minutes. Crazy, crazy man. My wife was yelling at the TV and she isn't even into football that much!
Tom
That game was crazy in the last two minutes. Crazy, crazy man. My wife was yelling at the TV and she isn't even into football that much!
Tom
Mass Coupling or Isolation?
Our experience bears out that experimenting is key. We believe in placing our products as close to the component being isolated as is possible. So, in the subwoofer/stand example above, we would first place our product between the subwoofer and its stand. After that, under the stand. It can take hours if not days for our product to fully settle, so snap judgments in minutes are discouraged. Additionally, speakers are critical so it's very possible, likely actually, that re-positioning may be necessary to restore the desired tonal balance.
John
Hello, Gary. I hope you are enjoying your weekend.
I am actually intrigued by this question, as I have always pondered this whilst listening but never got around to asking. In my particular case, it won't be for a bookshelf or mains but for the subs I have that I set on extremely heavy stands. IME, this yields a better overall presentation, spatial locational cues, impact and overall realism versus placing the subs on the floor. My subs are placed currently with the woofer at the tweeter/ear level. If you would be so kind, would you please mind sharing your thoughts on this subject?
Tom
Our experience bears out that experimenting is key. We believe in placing our products as close to the component being isolated as is possible. So, in the subwoofer/stand example above, we would first place our product between the subwoofer and its stand. After that, under the stand. It can take hours if not days for our product to fully settle, so snap judgments in minutes are discouraged. Additionally, speakers are critical so it's very possible, likely actually, that re-positioning may be necessary to restore the desired tonal balance.
John
Hi Gary,
I'm Tom's friend, Jesse. I thought I'd provide a bit more information to you and see what you think. The monitors are sealed two ways, tweeter at the bottom with modified crossovers. They weigh 18 to 20 lbs. and came with 1/2" tall semi-hard rubber feet on the bottom. The stands are twin column 4x4 PVC with a 1/2" thick MDF top plate and a 1" thick MDF bottom plate. The stands are spiked on a tile floor, which has texture, so it's not slick smooth. The stands do not move or slide around. Up until the other day the stands had 25 lbs. of lead shot in them, which only filled about 6" in each column. I removed the shot and replaced it with dry sand filling each column to the top, so about 40 lbs. in each stand. This resulted in improved clarity and got me wondering if I could get additional improvements by coupling (bolting) the monitors to the stands. As I looked around for information I found a lot of conflicting opinions, hence my post on another forum seeking even more opinions. I read your excellent article on the subject matter in the past and again recently. It appears that I will have to try it for myself (as usual, the best way), but if you have any insight before I do, it would be greatly appreciated.
Jesse
I'm Tom's friend, Jesse. I thought I'd provide a bit more information to you and see what you think. The monitors are sealed two ways, tweeter at the bottom with modified crossovers. They weigh 18 to 20 lbs. and came with 1/2" tall semi-hard rubber feet on the bottom. The stands are twin column 4x4 PVC with a 1/2" thick MDF top plate and a 1" thick MDF bottom plate. The stands are spiked on a tile floor, which has texture, so it's not slick smooth. The stands do not move or slide around. Up until the other day the stands had 25 lbs. of lead shot in them, which only filled about 6" in each column. I removed the shot and replaced it with dry sand filling each column to the top, so about 40 lbs. in each stand. This resulted in improved clarity and got me wondering if I could get additional improvements by coupling (bolting) the monitors to the stands. As I looked around for information I found a lot of conflicting opinions, hence my post on another forum seeking even more opinions. I read your excellent article on the subject matter in the past and again recently. It appears that I will have to try it for myself (as usual, the best way), but if you have any insight before I do, it would be greatly appreciated.
Jesse
Hi Jesse,
Sealed 2-way with the woofer at the top makes a significant difference from if the woofer was at the bottom (look at the vector forces and how they interact). The 1/2" tall semi-hard rubber feet would be elastic, so that would be an advantage. If the stands are 40lbs and spiked to a tile floor, they can be regarded as "foundation earth". Although, being made of PVC might make the stands visco-elastic and hence bolting the speakers to the stands might be detrimental.
Increasing the stiffness and weight of the stand might also improve things. So might replacing the rubber feet with various couplers/decouplers. I suspect that if you add some weight to the back of the speaker (like with a lead sheet) you might get more improvement along the same direction that you currently have achieved.
Sealed 2-way with the woofer at the top makes a significant difference from if the woofer was at the bottom (look at the vector forces and how they interact). The 1/2" tall semi-hard rubber feet would be elastic, so that would be an advantage. If the stands are 40lbs and spiked to a tile floor, they can be regarded as "foundation earth". Although, being made of PVC might make the stands visco-elastic and hence bolting the speakers to the stands might be detrimental.
Increasing the stiffness and weight of the stand might also improve things. So might replacing the rubber feet with various couplers/decouplers. I suspect that if you add some weight to the back of the speaker (like with a lead sheet) you might get more improvement along the same direction that you currently have achieved.
Hi Gary,
Thank you for your response. As I noted above the extra weight in the stands resulted in greater clarity, which seemed to be a good thing at the lower volume levels I had been listening at. However, I discovered at higher levels the sound became a bit etched. Taking into account your posts and that of allvinyl I placed some soft foam discs I had laying around under the semi-hard rubber feet in an effort to further de-couple the speakers. Hmmmm.....much smoother at higher levels and still nice a lower levels. At this point I've given up on the coupling idea and will experiment with other de-coupling devices.
Thanks again,
Jesse
Thank you for your response. As I noted above the extra weight in the stands resulted in greater clarity, which seemed to be a good thing at the lower volume levels I had been listening at. However, I discovered at higher levels the sound became a bit etched. Taking into account your posts and that of allvinyl I placed some soft foam discs I had laying around under the semi-hard rubber feet in an effort to further de-couple the speakers. Hmmmm.....much smoother at higher levels and still nice a lower levels. At this point I've given up on the coupling idea and will experiment with other de-coupling devices.
Thanks again,
Jesse
In my experiences over many years, I found that mass coupling goes so far. Once I started experimenting with isolation devices (uncoupling), I was able to surpass the best effect of mass coupling. I believe your conclusion about further experimenting with isolation after having taken the mass coupling tack has led you down the same path, eventually arriving at the same conclusion.
John
Hi Gary, and again thanks for the thread. Thought provoking with as much science as could be interjected without overwhelming the subject. Got it done and a couple of things have happened, both positive. The Sistrum Apprentice stands appear to have balanced the speakers out, to say that the overall presentation seems more seamless and at ease. I was certainly concerned as a more etched sound would have been a big disappointment. Smoothing things out was hoped for, and achieved in spades.
At the same time resolution, particularly in the vocals was hugely improved. The stands just make the presentation so much more natural. This science/art of sound reproduction is fascinating.
Now, a further question should you happen to view this thread in the future. My rack and amps are also coupled to the floor. Is it possible that all components coupled together on a unified surface could result in increased coherence? Because that's what seems to be happening here.
At the same time resolution, particularly in the vocals was hugely improved. The stands just make the presentation so much more natural. This science/art of sound reproduction is fascinating.
Now, a further question should you happen to view this thread in the future. My rack and amps are also coupled to the floor. Is it possible that all components coupled together on a unified surface could result in increased coherence? Because that's what seems to be happening here.
Glad that you got something useful out of this thread.
I wouldn't think that coupling the rest of the components with the loudspeaker could result in increased coherence. Going to the extreme - imagine coupling the loudspeaker to the turntable. You'd get a tremendous howl due to feedback.This could even happen with the tubes in a tube power amp if very microphonic.
I wouldn't think that coupling the rest of the components with the loudspeaker could result in increased coherence. Going to the extreme - imagine coupling the loudspeaker to the turntable. You'd get a tremendous howl due to feedback.This could even happen with the tubes in a tube power amp if very microphonic.
Thank you, Gary, for taking the time and effort to educate us about the complex issues associated with speaker coupling. And it does take a significant amount of time to provide the in-depth information that you have put together. So thank you again for that.
I would like to add another aspect to the issue which is the interact of the floor and wall structure with the speaker. As you have said, it is a complex issue even when just considering the effects upon the speaker's performance.
The other aspect that I would like to add is that the sound in the room is not just what the speaker is emanating. The floor and the walls act as secondary radiators. If a speaker is spiked into the floor, it will pump energy into the floor and cause it to vibrate and resonate. This physical coupling will propagate into the walls from the floor. The vibration and resonance of the floor and walls can be very significant to the total sound that we hear in the room. So whether you would want to couple or de-couple a speaker can be very dependent upon the room construction.
Try tapping your heal into the floor and listen for the natural resonance of the room itself. If you have a solid concrete floor you may not hear much. But if you have a suspended wooden floor, as I do, then the resonance can be quite severe. I actually put additional supports under the floor joists which helped significantly regardless of which speaker I used. Due to the construction of my room most speakers sound best decoupled from the floor to prevent pumping energy into the floor.
I would like to add another aspect to the issue which is the interact of the floor and wall structure with the speaker. As you have said, it is a complex issue even when just considering the effects upon the speaker's performance.
The other aspect that I would like to add is that the sound in the room is not just what the speaker is emanating. The floor and the walls act as secondary radiators. If a speaker is spiked into the floor, it will pump energy into the floor and cause it to vibrate and resonate. This physical coupling will propagate into the walls from the floor. The vibration and resonance of the floor and walls can be very significant to the total sound that we hear in the room. So whether you would want to couple or de-couple a speaker can be very dependent upon the room construction.
Try tapping your heal into the floor and listen for the natural resonance of the room itself. If you have a solid concrete floor you may not hear much. But if you have a suspended wooden floor, as I do, then the resonance can be quite severe. I actually put additional supports under the floor joists which helped significantly regardless of which speaker I used. Due to the construction of my room most speakers sound best decoupled from the floor to prevent pumping energy into the floor.
It's great to have access to the industry experts' depth of knowledge available on this forum. Of course everyone's room is different. My floors are hardwood on 3/4" plywood on concrete. It seems, reading through all the posts in this thread, that truly the different factors result in different solutions. Many variables here, each factoring into the SQ and the application of systems that best bring that out. For me, it has resulted in finally being able to hear clearly the vocals of some of my favorites as well as improved tone and coherence. Next comes addressing some intractable residual hum that's proving to be a real bear.
I've got a similar situation and, with bare feet, it's dead simple to feel the floor vibrating when music is playing. The (old) floorboards also creak and flex so external vibrations to the speakers must also be a factor. Isolation seems like the right anser - how would something like http://www.townshendaudio.com/hi-fi-home-cinema-equipment-vibration-isolation/seismic-isolation-bars-for-speakers-subwoofers/ work? The speakers are very heavy so any solution that requires cleaning (ball and cup) is a no-go.
I haven't seen that particular solution from Townshend Audio. There are also "pro" versions that are similar by IsoAcoustics.
However, as with all isolation components that rely on compliant mounts, the resonant frequency depends on the weight that they carry. Resonant frequency goes up as the weight goes up on a compliant mount. Beyond their elastic load limits, they no longer work. I think the solution would depend on the weight of your speakers.
However, as with all isolation components that rely on compliant mounts, the resonant frequency depends on the weight that they carry. Resonant frequency goes up as the weight goes up on a compliant mount. Beyond their elastic load limits, they no longer work. I think the solution would depend on the weight of your speakers.
Perfect timing for me to comment!
I finally got around to changing the spikes on my Usher BE20D speakers (~300lbs each). I switched from the stock brass spikes which are not very pointy at all and essentially kept the speaker "floating" on the carpet above the suspended wood floor to Track Audio stainless steel (and very pointy) spikes. I immediately noticed an improvement in bass tightness and increased bass energy. More so than I expected. Net - Coupling 600+lbs rather than floating makes a significant difference in bass clarity and output, at least in my case.
I finally got around to changing the spikes on my Usher BE20D speakers (~300lbs each). I switched from the stock brass spikes which are not very pointy at all and essentially kept the speaker "floating" on the carpet above the suspended wood floor to Track Audio stainless steel (and very pointy) spikes. I immediately noticed an improvement in bass tightness and increased bass energy. More so than I expected. Net - Coupling 600+lbs rather than floating makes a significant difference in bass clarity and output, at least in my case.
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