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Attn: John Atkinson
"Powell" asked:
"John Atkinson" wrote I did a thorough study of this back in 1992. The results are reprinted at http://www.stereophile.com/features/806/. Supporting a speaker on spikes rather than a lossy interface of some kind allows the cabinet resonances to develop fully. June 1992? I don't see it in the index. Where in the 322 pages is it? 324 pages (we start the folio numbering on the front cover, which is page 1). The article on cabinet resonances starts on p.205 and continues through p.207. I then followed up the subject in September 1992. All my discussion from both issues is included in the Web reprint that I referenced above. John Atkinson Editor, Stereophile |
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#2
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John Atkinson
"John Atkinson" wrote in message om... "Powell" asked: "John Atkinson" wrote I did a thorough study of this back in 1992. The results are reprinted at http://www.stereophile.com/features/806/. Supporting a speaker on spikes rather than a lossy interface of some kind allows the cabinet resonances to develop fully. June 1992? I don't see it in the index. Where in the 322 pages is it? 324 pages (we start the folio numbering on the front cover, which is page 1). The article on cabinet resonances starts on p.205 and continues through p.207. I then followed up the subject in September 1992. All my discussion from both issues is included in the Web reprint that I referenced above. Great article! As I write this, I'm having a telephone conversation with my friend Larry Zeitz, who insists there must be an escape clause for downward pointing, carpet piercing, floor spikes on floor standing speakers, and the interface between stands and floors. I have responded that your article offers no implication that spikes are useful for the floor interface. Would you be so kind as to comment? |
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#4
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John Atkinson
"Nousaine" wrote in message ... "Robert Morein" wrote: "John Atkinson" wrote in message . com... "Powell" asked: "John Atkinson" wrote I did a thorough study of this back in 1992. The results are reprinted at http://www.stereophile.com/features/806/. Supporting a speaker on spikes rather than a lossy interface of some kind allows the cabinet resonances to develop fully. June 1992? I don't see it in the index. Where in the 322 pages is it? 324 pages (we start the folio numbering on the front cover, which is page 1). The article on cabinet resonances starts on p.205 and continues through p.207. I then followed up the subject in September 1992. All my discussion from both issues is included in the Web reprint that I referenced above. Great article! As I write this, I'm having a telephone conversation with my friend Larry Zeitz, who insists there must be an escape clause for downward pointing, carpet piercing, floor spikes on floor standing speakers, and the interface between stands and floors. I have responded that your article offers no implication that spikes are useful for the floor interface. Would you be so kind as to comment? About this time I conducted a single blind listening test to find the worth of speaker support and sonics. I purchased 4 Snell KII loudspeakers with the assurance that they had been sequentially manufactured and verified that they all met the specification of 0.5 dB frequency response relative to the standard. Of course i didn't have that standard speaker but each of the 4 were well within a half dB of each other. I then borrowed a set of target speaker stands, filled each with 25# of lead shot, and affixed spikes to the bottom of the stands and the stand pads that would anchor the speakers. Wishing to maximize the possible sonic differences I then devised a competing "stand" which was an empty 12-inch woofer carton, duct taped to a stamped steel Bose 901 stand whch was then brought to height with copies of the JAES and paperback books. I then conducted a number of single listener, single blind listening tests with randomized speaker location. The results were that listeners had a preference for speaker location BUT stand-interface wasn't a decision making element. These were listener switched tests BTW. Each listener had control over all aspects of program delivery. I then conducted a series of single listener single blind tests with Uh, Tom. I think you forgot something. |
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#5
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John Atkinson
"Michael McKelvy" wrote:
"Nousaine" wrote in message ... "Robert Morein" wrote: "John Atkinson" wrote in message . com... "Powell" asked: "John Atkinson" wrote I did a thorough study of this back in 1992. The results are reprinted at http://www.stereophile.com/features/806/. Supporting a speaker on spikes rather than a lossy interface of some kind allows the cabinet resonances to develop fully. June 1992? I don't see it in the index. Where in the 322 pages is it? 324 pages (we start the folio numbering on the front cover, which is page 1). The article on cabinet resonances starts on p.205 and continues through p.207. I then followed up the subject in September 1992. All my discussion from both issues is included in the Web reprint that I referenced above. Great article! As I write this, I'm having a telephone conversation with my friend Larry Zeitz, who insists there must be an escape clause for downward pointing, carpet piercing, floor spikes on floor standing speakers, and the interface between stands and floors. I have responded that your article offers no implication that spikes are useful for the floor interface. Would you be so kind as to comment? About this time I conducted a single blind listening test to find the worth of speaker support and sonics. I purchased 4 Snell KII loudspeakers with the assurance that they had been sequentially manufactured and verified that they all met the specification of 0.5 dB frequency response relative to the standard. Of course i didn't have that standard speaker but each of the 4 were well within a half dB of each other. I then borrowed a set of target speaker stands, filled each with 25# of lead shot, and affixed spikes to the bottom of the stands and the stand pads that would anchor the speakers. Wishing to maximize the possible sonic differences I then devised a competing "stand" which was an empty 12-inch woofer carton, duct taped to a stamped steel Bose 901 stand whch was then brought to height with copies of the JAES and paperback books. I then conducted a number of single listener, single blind listening tests with randomized speaker location. The results were that listeners had a preference for speaker location BUT stand-interface wasn't a decision making element. These were listener switched tests BTW. Each listener had control over all aspects of program delivery. I then conducted a series of single listener single blind tests with Uh, Tom. I think you forgot something. Yes; I forgot to 'cut' that last phrase :-) Thnx. |
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#6
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John Atkinson
"Robert Morein" wrote in message ...
"John Atkinson" wrote in message om... Great article! Thanks. As I write this, I'm having a telephone conversation with my friend Larry Zeitz, who insists there must be an escape clause for downward pointing, carpet piercing, floor spikes on floor standing speakers, and the interface between stands and floors. I have responded that your article offers no implication that spikes are useful for the floor interface. Would you be so kind as to comment? There are 2 separate issues involved. The first is the speaker cabinet's vibrational behavior, which is what I examined in my on-line article. The second is the speaker's and/or stand's relationship to the floor. There is no doubt that supporting a speaker or its stand on downward-pointing spikes more efficiently couples vibrational energy to the floor. This can be easily demonstrated if you have a room beneath your listening room, or of you live in an apartment, can get access to the apartment beneath yours. Rest the speakers or their stands on the carpet without spikes. Play music with plenty of repetitive low frequencies and listen from downstairs. You will hear a muffled rendition of the bass. Now repeat the music at the same level with the speakers/stands spiked to the floor. Again listen from downstairs and you will hear the bass notes louder and more clearly defined, depending, of course, on your floor construction. (Spiking your speakers to the floor is an excellent way, BTW, of maximally annoying your downstairs neighbors, if that is a goal. :-) ) You might also want to try wedging a pole between the back of the speaker and the wall behind it. (The pole whould be very slightly longer than the distance so it is under compression and the speaker is not moved forward.) Depending on the speaker, you might hear an improvement in bass definition. Then again, you might not. BTW, the worst case, in my experience, is to suspend the speakers on cords of some kind, as recommended by Arny Krueger. What general conclusions can be drawn? From my own experience with concrete slab floors, the speakers will sound slightly better defined in the lower midrange and bass when they are spiked to the floor beneath the carpet. With suspended floors, whether there is an improvement or not will be a crapshoot. With the cabinet itself, supporting the speaker on upturned spikes will allow its own resonances to develop fully, as my 1992 measurements demonstrated As I said earlier, whether or not this will degrade the speaker's perceived sound quality or not will differ from speaker to speaker. My measured results also show that if you want to maximally damp cabinet resonances, you should use a lossy interface such as Blu-Tack between the cabinet and its support. What you _don't_ want is a compliant, non-lossy interface material, like a typical carpet pad, or springy rubber feet. You will change the resonant behavior rather than damping it, and you might well amplify sme of the cabinet resonant modes. Again, this is something I examined in my 1992 articles. So, it is relatively easy to try spikes then Blu-Tack, to determine which (if either) you prefer. Listen to just one speaker and play something like the half-step-spaced tonebursts on Stereophile's "Editor's Choice" CD. Listen for overhang on some notes but not others, a "pulling" of the pitch of some notes but not others, and a general stability or lack thereof to pitch centers. Go with what you prefer. If you don't hear any difference, then it is possible that your speaker cabinets are optimally braced. John Atkinson Editor, Stereophile |
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#7
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John Atkinson
"Nousaine" wrote in message ... "Robert Morein" wrote: "John Atkinson" wrote in message . com... "Powell" asked: "John Atkinson" wrote I did a thorough study of this back in 1992. The results are reprinted at http://www.stereophile.com/features/806/. Supporting a speaker on spikes rather than a lossy interface of some kind allows the cabinet resonances to develop fully. June 1992? I don't see it in the index. Where in the 322 pages is it? 324 pages (we start the folio numbering on the front cover, which is page 1). The article on cabinet resonances starts on p.205 and continues through p.207. I then followed up the subject in September 1992. All my discussion from both issues is included in the Web reprint that I referenced above. Great article! As I write this, I'm having a telephone conversation with my friend Larry Zeitz, who insists there must be an escape clause for downward pointing, carpet piercing, floor spikes on floor standing speakers, and the interface between stands and floors. I have responded that your article offers no implication that spikes are useful for the floor interface. Would you be so kind as to comment? About this time I conducted a single blind listening test to find the worth of speaker support and sonics. I purchased 4 Snell KII loudspeakers with the assurance that they had been sequentially manufactured and verified that they all met the specification of 0.5 dB frequency response relative to the standard. Of course i didn't have that standard speaker but each of the 4 were well within a half dB of each other. I then borrowed a set of target speaker stands, filled each with 25# of lead shot, and affixed spikes to the bottom of the stands and the stand pads that would anchor the speakers. Wishing to maximize the possible sonic differences I then devised a competing "stand" which was an empty 12-inch woofer carton, duct taped to a stamped steel Bose 901 stand whch was then brought to height with copies of the JAES and paperback books. I then conducted a number of single listener, single blind listening tests with randomized speaker location. The results were that listeners had a preference for speaker location BUT stand-interface wasn't a decision making element. These were listener switched tests BTW. Each listener had control over all aspects of program delivery. And were you surprised at the results? :-) |
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#8
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John Atkinson
"John Atkinson" wrote in message om... "Robert Morein" wrote in message ... "John Atkinson" wrote in message om... Great article! Thanks. As I write this, I'm having a telephone conversation with my friend Larry Zeitz, who insists there must be an escape clause for downward pointing, carpet piercing, floor spikes on floor standing speakers, and the interface between stands and floors. I have responded that your article offers no implication that spikes are useful for the floor interface. Would you be so kind as to comment? There are 2 separate issues involved. The first is the speaker cabinet's vibrational behavior, which is what I examined in my on-line article. Having read the online article, it's kind of amazing that you went to Glass Audio for reference but not the audioXpress article from Feb.2002 by Jim Moriasu, a protege of Dickason's. He tested particle board, MDF, double layered MDF, constrained layered materials, sand filled panels,seven ply plywood, triple layerd MDF, MDF wioth Black Hole Damping material,Deflex panelsIsodamp, Sorbothane,North Creek soft glue, and more. The bottom lne is you can't get rid of cabinet vibrations but you can reduce them with extensional damping. As far as I know nothing that a stand does, aside from raising the speakers up to proper listening height, will do anything about vibration. |
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#9
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John Atkinson
"Michael McKelvy" wrote:
"Nousaine" wrote in message ... "Robert Morein" wrote: "John Atkinson" wrote in message . com... "Powell" asked: "John Atkinson" wrote I did a thorough study of this back in 1992. The results are reprinted at http://www.stereophile.com/features/806/. Supporting a speaker on spikes rather than a lossy interface of some kind allows the cabinet resonances to develop fully. June 1992? I don't see it in the index. Where in the 322 pages is it? 324 pages (we start the folio numbering on the front cover, which is page 1). The article on cabinet resonances starts on p.205 and continues through p.207. I then followed up the subject in September 1992. All my discussion from both issues is included in the Web reprint that I referenced above. Great article! As I write this, I'm having a telephone conversation with my friend Larry Zeitz, who insists there must be an escape clause for downward pointing, carpet piercing, floor spikes on floor standing speakers, and the interface between stands and floors. I have responded that your article offers no implication that spikes are useful for the floor interface. Would you be so kind as to comment? About this time I conducted a single blind listening test to find the worth of speaker support and sonics. I purchased 4 Snell KII loudspeakers with the assurance that they had been sequentially manufactured and verified that they all met the specification of 0.5 dB frequency response relative to the standard. Of course i didn't have that standard speaker but each of the 4 were well within a half dB of each other. I then borrowed a set of target speaker stands, filled each with 25# of lead shot, and affixed spikes to the bottom of the stands and the stand pads that would anchor the speakers. Wishing to maximize the possible sonic differences I then devised a competing "stand" which was an empty 12-inch woofer carton, duct taped to a stamped steel Bose 901 stand whch was then brought to height with copies of the JAES and paperback books. I then conducted a number of single listener, single blind listening tests with randomized speaker location. The results were that listeners had a preference for speaker location BUT stand-interface wasn't a decision making element. These were listener switched tests BTW. Each listener had control over all aspects of program delivery. And were you surprised at the results? :-) No; frankly it didn't surprise me. But to my knowledge no one had (or otherwise has to this date) conducted a bias-controlled listening test compensating for speaker position as a variable examining the conventional wisdom. |
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#10
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John Atkinson
"Michael McKelvy" wrote There are 2 separate issues involved. The first is the speaker cabinet's vibrational behavior, which is what I examined in my on-line article. Having read the online article, it's kind of amazing that you went to Glass Audio for reference but not the audioXpress article from Feb.2002 by Jim Moriasu, a protege of Dickason's. "Feb.2002 by Jim Moriasu and/or Jim Moriasu ... reference link, please? He tested particle board, MDF, double layered MDF, constrained layered materials, sand filled panels,seven ply plywood, triple layerd MDF, MDF wioth Black Hole Damping material,Deflex panelsIsodamp, Sorbothane, North Creek soft glue, and more. Each of these materials and many others all have merit. Each material will absorb audio energy but will do so based on a number of material science issues. None will be equally absorbent across the audio spectrum. In addition each will have optimum absorption and failure (soft to loud). Further complicating the issue is the application of the material themselves into component parts for assembly. In these terms the speaker box is no longer a monolithic structure it is a system. A thesis could be written on the modeling required to predict all the variables in play (system). The bottom lne is you can't get rid of cabinet vibrations but you can reduce them with extensional damping. I’ve been impressed with designs by Wilson Audio (http://www.wilsonaudio.com/finishes/index.html) and Eglestonworks (http://www.egglestonworks.com/Customers.htm) in this regard. They appear by touch to remain inert when the hand is placed on them during medium levels of volume play. As far as I know nothing that a stand does, aside from raising the speakers up to proper listening height, will do anything about vibration. "I know nothing"... do you mean that you have nothing to contribute to the discussion or you’ve never owned speakers that used spikes (no experiences)? |
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#11
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John Atkinson
Powell wrote:
(http://www.egglestonworks.com/Customers.htm) in Great, the above ones look like coffins... I understand that they are totaly inert! ;-) Both manufacturers are lying when they write : "Drivers are manufactured on a special production line under laboratory conditions." ....or similar |
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#12
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John Atkinson
(John Atkinson) wrote in message . com...
"Robert Morein" wrote in message ... "John Atkinson" wrote in message om... Great article! Thanks. As I write this, I'm having a telephone conversation with my friend Larry Zeitz, who insists there must be an escape clause for downward pointing, carpet piercing, floor spikes on floor standing speakers, and the interface between stands and floors. I have responded that your article offers no implication that spikes are useful for the floor interface. Would you be so kind as to comment? There are 2 separate issues involved. The first is the speaker cabinet's vibrational behavior, which is what I examined in my on-line article. The second is the speaker's and/or stand's relationship to the floor. There is no doubt that supporting a speaker or its stand on downward-pointing spikes more efficiently couples vibrational energy to the floor. This can be easily demonstrated if you have a room beneath your listening room, or of you live in an apartment, can get access to the apartment beneath yours. Rest the speakers or their stands on the carpet without spikes. Play music with plenty of repetitive low frequencies and listen from downstairs. You will hear a muffled rendition of the bass. Now repeat the music at the same level with the speakers/stands spiked to the floor. Again listen from downstairs and you will hear the bass notes louder and more clearly defined, depending, of course, on your floor construction. (Spiking your speakers to the floor is an excellent way, BTW, of maximally annoying your downstairs neighbors, if that is a goal. :-) ) You might also want to try wedging a pole between the back of the speaker and the wall behind it. (The pole whould be very slightly longer than the distance so it is under compression and the speaker is not moved forward.) Depending on the speaker, you might hear an improvement in bass definition. Then again, you might not. BTW, the worst case, in my experience, is to suspend the speakers on cords of some kind, as recommended by Arny Krueger. What general conclusions can be drawn? From my own experience with concrete slab floors, the speakers will sound slightly better defined in the lower midrange and bass when they are spiked to the floor beneath the carpet. With suspended floors, whether there is an improvement or not will be a crapshoot. With the cabinet itself, supporting the speaker on upturned spikes will allow its own resonances to develop fully, as my 1992 measurements demonstrated As I said earlier, whether or not this will degrade the speaker's perceived sound quality or not will differ from speaker to speaker. My measured results also show that if you want to maximally damp cabinet resonances, you should use a lossy interface such as Blu-Tack between the cabinet and its support. What you _don't_ want is a compliant, non-lossy interface material, like a typical carpet pad, or springy rubber feet. You will change the resonant behavior rather than damping it, and you might well amplify sme of the cabinet resonant modes. Again, this is something I examined in my 1992 articles. So, it is relatively easy to try spikes then Blu-Tack, to determine which (if either) you prefer. Listen to just one speaker and play something like the half-step-spaced tonebursts on Stereophile's "Editor's Choice" CD. Listen for overhang on some notes but not others, a "pulling" of the pitch of some notes but not others, and a general stability or lack thereof to pitch centers. Go with what you prefer. If you don't hear any difference, then it is possible that your speaker cabinets are optimally braced. John Atkinson Editor, Stereophile From other data I've seen the fundamental resonance frequency of the floor-speaker interface is in the bass region (20-50 Hz) when using spikes, and by using coupling there will be significant movement of the speakers when the resonance is excited (up to 20 dB more). With soft feet the fundamental resonance of the speaker-floor interface can be reduced to under 10 Hz and will not be excited with most music material. The resonance in the cabinet per se should IMO be dealt with using a good cabinet construction. Also, springy floors will be problematic using hard coupling since the standing waves in the room will excite the floor and cause significant speaker movement. Isolation with springy feet will make the speaker move less. See e.g. http://koti.welho.com/msalone5/audio/vibra.html Although the text is in Swedish, the graphs should not be difficult to interpret. T |
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