bdiament

Hi AnotherSpin, A hole in the board is a good idea. It eliminates the need for the straw too. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi John, I don't believe a well-designed roller will "care" about the weight of the load. I have them under quite light DVD players and line stages, as well as under quite heavy amps, speakers, and subwoofers. My feeling is the less there is between the rollers and what they isolate, the less there is to isolate. Not a matter of weight but a matter of what there is to "shake." Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi Dave, The "problem" here is that you are speaking from direct experience as opposed to not having any experience with this, theorizing a lot (often erroneously), and simply repeating what others have said as if you discovered it. Now who am I going to believe about how the water feels: Someone who has spent some good time swimming? Or someone who might have (or might not have) dipped their toe in once? ;-} My experience matches yours: the air bearing works well vertically and doesn't do much horizontally. To be clear, it might be more than zero in the horizontal plane but it is essentially close enough to zero that this is how I think of it. And rotationally, does even less. That is why I feel the rollers are such a good idea. (And it is probably why air bearings aren't used under skyscrapers in earthquake-prone areas, while rollers are.) Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi sig8, The question becomes, is the tube as flexible and "loose" as it would be in its normal (valve facing inward) state? I would tend to think it is more "tight" with the valve outside, making it stiffer. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi John, I believe your assumption makes sense. However, I've also found that isolation seems to work best when it is placed as close as possible to that which we wish to isolate. In this case, having tried (and currently using) both, I find giving "priority" to the rollers (i.e., the horizontal and rotational planes) to be sonically advantageous. Does this mean horizontal vibrations potentially do more damage than vertical ones? I don't know but I think this is a possibility. Another, perhaps stronger possibility is that there just happen to me more horizontal ones than vertical ones. (To my current understanding -- always subject to modification of course -- seismologists refer to the former as "primary" and the latter as "secondary".) Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi John, Are you using the rollers below the air bearing? If so, have you tried it the other way (shelf - air bearing - platform - rollers - component or tile-component)? The main thing is you are happy with the results. I wonder if reversing the setup (rollers on top) might make you even happier? Just a thought. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi Dave, Understood about the floor. However, I still don't see this means vibrations in the floor are necessarily traveling vertically as opposed to horizontally. Not sure how this could best be measured. Probably have to look into how seismologists do it. (There's a job. I can imagine a kid somewhere saying: "When I grow up, I want to be a seismologist." ;-}) Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi sig8, I'd leave the valve on the inside. As Dave rightly points out, there is less rubber on the inside of the circle than there is on the outside. A flexible valve extension helps with access. And yes, it *may* also provide enough of a gap to remove the need for the straw. However, it may also make for a bit of tilt. You would need to experiment to see. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi Dave, I saw the post, then got distracted by some non-audio necessities (aka Life and the health of a loved one who was in the hospital for a heart operation). Also, I didn't really have much to say. I don't know that I would draw the same conclusions, i.e., that the vibrations were vertical in nature. Even if the subs are in direct contact with the floor (I'd consider "floating" them too. ;-}) and even if the floor is suspended on joists, I could be mistaken (of course) but I don't see why these would suggest the vibrations in the floor itself travel across the floor vertically rather than horizontally. Vibrations may *enter* the floor vertically but I'm not so sure this means they stay that way once the floor is energized. As I said, I don't know. I would just tend to think the *primary* vibrations are horizontal if they are felt in a part of the room well away from where the subs contact the floor. Not to say the floor isn't *also* moving vertically. I'm thinking of seismic vibrations in the earth: the P (primary) waves move horizontally, the S (secondary) waves move vertically. Those P waves are what appear to do most of the damage. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi sig8, I'm at a loss to figure out why an 18" inner tube is describing a circle much more than 18". I'm using 18" x 1.75" inner tubes and they would appear to describe nothing larger than an outer diameter of 19" or a bit less. I have them under 20" x 20" platforms and the inner tubes stop a least 1/2" before the edge. I prefer to have the full surface of the inner tube covered, with nothing bulging beyond the edge of the platform. First thing I'd suggest is to ascertain whether those are in fact 18" inner tubes, or were perhaps mislabeled. If they are, and they describe a circle much larger than 18", I'm still at a loss, but would then suggest trying a 16" tube (or another 18" to be positive you have the right size). Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi Foggie, That is correct. I made two racks but each is single-wide -- the shelves can easily hold a component that is a bit over 20" wide by 20" deep and close to a foot tall. I made two because I wanted each component to have its own shelf. (However, the shelf with the power distribution block also has the power supply for the converters on it.) Excellent! It is always great to hear success stories from fellow music and audio enthusiasts. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi Dave, Why assume the floor vibrations you felt were vertical? If the waves were moving horizontally along the floor, that *might* explain why the roller-isolated speakers did not respond. (It may *see* vertical if looking at a small, separate section of floor as the waves pass by. I don't know. Just speculating.) I don't know in which plane the floor vibrations were moving. The speakers are coupled to the floor in the vertical plane but isolated in the horizontal (and rotational) planes. Particularly in view of the speakers' non-response, I would ask "why assume they were vertical?" Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi Jud, Sure! We can all ask for adjacent cells. And share basket weaving tips. ;-} Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

One thing to keep in mind is that once hardness is sufficient (to avoid denting, scoring, etc.), ringing becomes a consideration. So going for the hardness spec alone, much like going for *any* spec alone, can take one down a needless - and often wrong - path. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi 4est, Not sure about any claims of softness for marble. I've had marble tiles under heavy Magnepan 3.6s, 3.7s, and 3.7i's, under heavy power amplifiers, and under much heavier subwoofers for many years, with no issues, no scoring, etc. Granite on the other hand, has a tendency to ring, so I'd be careful of that. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi Foggie, Not sure if the reference being referenced (;-}) is what I referred to (;-}) but if it is, I use 20" x 20" x 1" maple ply platforms under everything in my Enjoyyourshelf racks, which were designed to accommodate the largest components I might consider putting on them at any future date. Under my speakers and subs, the size of the 1" thick platforms was made to exactly match the footprints of my Magnepans and the larger footprints of the subs. (They're roughly 19" x 19" for the Maggies and larger rectangles under the subs.) I use 18" x 1.75" inner tubes under the 20 x 20 platforms on the racks. (No inner tubes under the speakers or subs, which are just on roller bearings, with 18" x 18" x 3/8" marble tiles between the rollers and the platforms. While .5 is fine, I would add that the tiles under my speakers, amps, and subwoofers (all heavy) are 3/8" thick, with no issues at all after a decade or more. So, if the tile is the right tile, I don't believe there is any problem at all with 3/8" thickness. At least, that has been my experience so far. sig8, I'd recommend 1" ply for the platforms over 3/4" simply because it is more rigid, and less prone to warping over time. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

=8-0 Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi sig8, I have never had any issues with things sliding off roller bearings or air bearings. That said, I have always offered a few caveats: 1. If a remote control is not used, one must develop a gentle touch on front panel controls. Stabilizing a component with one hand while operating the controls with the other works. I've also found that I can use a few fingers to stabilize a component and press a button with the thumb on the same hand. Or just be gentle with a normal button push. The component will jiggle but that is simply an indication that the isolation is working. 2. One must be mindful of some pets, small children, and guests in the listening room. My cats and large dog have often visited the studio/listening room and luckily, I've had no issues at all. I routinely warn first-time guests to stay clear of the speakers. (A quick visual demo where I show them the speakers will move easily is always sufficient.) 3. Changing air pressure in an air bearing usually requires one disconnect the component, remove it, remove the platform, change the inflation, restore the platform, restore the component, and reconnect. Flexible valve extensions can be used to avoid all this, allowing inflation adjustment while the music is playing (!). One thing to keep in mind is that most of the commercial products involve more damping on the ability of the isolator to move. This makes things less "jiggly" and it also means there is appreciably *less* isolation. (Greater damping = slower rolloff above resonance = less isolation.) The best, most effective isolators will theoretically be like having the components supported by Jello on springs. ;-} In practice, even with minimal damping, things are much more stable than that. There is still a sense of the Jello but as long as nobody (or nothing) crashes into the gear, all has been completely fine in my experience. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi sdolezalek, The weight of the load *combined* with the amount of inflation is involved in determining the resonance frequency of an air bearing. (The material and construction of the air bearing will also be involved but once selected, this will not change with different loads.) The heavier the load, the more inflation required to reach a given resonance. In other words, for a given resonance frequency--ideally, one in the low single digits--the weight of the load determines the required amount of inflation. With the correct amount of inflation thus determined, the resonance frequency will not be different. This is much like arm/cartridge resonance in a turntable setup: a more compliant cartridge requires a less massive arm in order to achieve the desired resonance frequency (in the case of turntables, this will be around 10 Hz -- below audio frequencies but above warp frequencies). Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi Dave, Aside from the pneumatic resistance created by a seal of the inside of the circle described by the inner tube when there is a shelf below and a platform above, that "chamber" will have a resonance of its own. If one can't put a hole in either the shelf or platform, as you mentioned, a small straw crossing from the inside of the circle to the outside will accomplish breaking the potential seal of the inside of the circle. For folks who are having trouble visualizing this, picture a letter Q (or an upside down Q if you place the straw toward the back of the inner tube). I've always suggested the straw to folks trying inner tubes for isolation but forgot about it in this thread until I went to respond to your post. Then I saw that you covered it. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

I would suggest using a "platform" sized to completely cover any inner tube used under it. The IKEA item linked to in an earlier post is 11" x 17" which I would take to limit inner tube size to about 10" -- in my experience, quite a bit too small to work well - unless you don't mind lop-sided gear. Neither I wouldn't want parts of the inner tube bulging outside of the platform. Hence, the symmetrical, square shape I chose for the platforms on the Enjoyyourshelf rack. (The rack size was determined *after* the required platform size.) Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi sig8, I've not noticed any ill effects from sharing a platform with a second, smaller item. One shelf on my rack has the QBase ac distribution block and the power supply for my ULN-8 converters. Each has its own Hip Joint roller bearing set but they both share the same 20" x 20" x 1" maple ply platform atop a single 18" x 1.75" inner tube. (They are also at opposite ends of the platform, to keep them separated as much as possible.) Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi sig8, My experience has been that the larger the circle described by the inner tube, the easier it is to level the component it supports. (Of course, this requires a larger shelf too, in order to accommodate the entire inner tube.) This may be less of an issue with small, or light components, so experimentation is always a good idea. That said, I've also found that tubes that describe smaller circles tend to be a little stiffer than those that describe larger circles. A soft, floppy tube will be easier to keep at minimal inflation. Remember to inflate *only* enough so the load is not resting on the inflation valve. One pump too much and the benefits drop rapidly while the bass will tend to bloat. (Again, proper isolation will not alter tonality.) And remember air bearings will need periodic inflation readjustment - just like any other use of an inner tube. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi sig8, I would recommend against small plates of any material. (Glass, in my view, is a bad choice anyway because it flexes. The contact surfaces must be very smooth *and* very hard. Glass might be smooth but it isn't hard enough.) Small plates tend to "chatter" resulting in a brightening of the sound. Proper isolation will not alter the tonality at all. If you are willing to use plywood, the combination with a tile will help deaden any tile. I seek out dead tiles but in almost all instances, combine these with plywood (where the edges have been neatly rounded and the appearance "warmed" with Watco's Danish oil). In my experience, tile --if it is smooth enough-- works better than a sheet of metal and is almost always less prone to ringing. With a plywood completely covering it, the main thing for the tile is a very smooth surface to face downward atop the roller bearing balls. I suggest a thicker tile too, e.g., 1/2". Hope this helps. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio

Hi Teresa, Of course the recording is what makes the sound. As I often say, once the signals have left the microphones, 90-95% or more of the recording's ultimate quality ceiling has already been determined. Everything after that, including mic cables, mic preamps, ac power, recording device, recording format, mix (if any), mastering, delivery format, and playback setup, only determines how much of what was captured we get to hear (or not). With the chain being only as strong as its weakest link, delivery format, being one of those things, will have an impact on how much of what was captured the listener does or does not hear. So while I believe it is good to consider the recording itself, as well as all the other things involved in getting from the performance to the listening room, I think the question the OP asked here is a separate issue. Yes, if the recording is bad, one might ask if anything else matters. My response would be that in a lot of ways, most recordings could be better. Sometimes a lot better. Still, as dedicated listeners, we know that the care we take with our systems and the formats we choose to purchase will have an important impact on the listening experience -- even with less than perfect recordings... which would cover the preponderance of what we have in our libraries. Best regards, Barry Soundkeeper Recordings http://www.soundkeeperrecordings.wordpress.com Barry Diament Audio