I’m looking to build some quality “Isolation Stands” for Hi-Fi equipment (CD players, etc.). These platforms will be roughly 22″W x 16″D x 1.75″H. I see some on the market that use maple, as well as various exotics. Basic idea is to dampen the equipment from the floor as much as possible, with minimal resonance.
I want to use solid hardwood, and would like understand any theory related to material selection.
All suggestions or links are welcome.
Replies
Conventional wisdom runs contrary to using hardwood. Stringed instruments are made of solid wood because it resonates. On the otherhand most hi-fi speaker cabinets use sheet goods because they don't. That said and based on your dimensions I'd try sand or foam filled torsion box construction with 1/4" thick, quartersawn top and bottom skins.
The benefits of acoustic isolation pads, feed, etc. were fairly debatible back in the golden years of the turntable. Especially for high-end turn-tables with excellent platten and arm suspension to begin with. That's not to say that it wasn't fun to chase the holy grail. I sketched-up but never built a hydraulic driven (ext pump) and suspended turntable using an automotive flywheel as the platter and a cast concrete base. Too bad I couldn't afford an Oracle or the 3 Arm Micro-Seiki or a nice Lynn, but I did have a nice Beogram Linear and a old clock motor AR that I restored. I couldn't hear the difference with a pad under the B&O, but it did help the primitive AR.
I just finished a new solid walnut Maloof-style A/V console. It includes a slide out turntable platform for my Dual CS5000. I haven't finalized it's location yet, so I haven't ordered cables and hooked it up to try it out and hear if I need a pad.
So this brings me around to my question. Is there really a measurable benefit (BER?) to acoustic isolation of a high-end optical drive? Or an audible one?
John O'Connell - JKO Handcrafted Woodworking
The more things change ...
We trained hard, but it seemed that every time we were beginning to form up into teams, we would be reorganized. I was to learn later in life that we tend to meet any new situation by reorganizing; and a wonderful method it can be for creating the illusion of progress while producing confusion, inefficiency, and demoralization.
Petronious Arbiter, 210 BC
If the optic has to work overtime to remain focused on the disc, the chance of going out of focus is high. Also, the error correction needs to work more and that can cause some issues, if it's constantly active at a high level. This is one reason I'm amazed many current models of CD and DVD players even work- they're so light there's no chance that sound isn't affecting them. To get to another part of your question- if it's a high-end optical device, I would hope it would be pretty impervious to this. I know many of the top models from Denon and some others are a lot heavier and I have seen Japanese Sony Audio Lab (their higher end line in the '70s - '90s) that came with a stone slab that was to be placed on top of each piece of equipment. On the high-end fringe nutjob end, they talk about isolating everything, but I went to look at some turntables for a customer last week and that shop sells Linn, Pro-Ject (Sumiko) and another brand that escapes me, but it more than I would ever spend on one, and one of the guys told me that above 2 on the volume control, the one upstairs howls like a wolf. Pretty sad for a very expensive turntable. This is mainly because the floor is very "active" and even after I told them that it could be made rigid for not a lot of money, I don't know if it'll happen.
"I cut this piece four times and it's still too short."
I've seen one source selling nice slabs of 8/4 maple at about $200 per board foot. I think the high price makes for better sounding audio. Of course, the Emperor had some mighty fine tailors.
How about $4900 for a 6' pair of interconnects? No, I didn't omit the decimal. Four thousand, nine hundred dollars. One pair, six feet long. But, they're really good.
"I cut this piece four times and it's still too short."
Really good, like the speaker cables that add wonderful "clarity", if they don't cause your power amp to become unstable.
I assume you're referring to the Kimber Cable and Krell combo of the late '70s/early '80s, right?
"I cut this piece four times and it's still too short."
Makes sense. I would expect that the really high end "nut-job" CD transports would employ some sort of dampening system, maybe even an active system. Nakamichi made a turn table where the outer table was connected to the inner table by servos. The servos would compensate for the slight deviation of the spindle hole from the true center of the LP.John O'Connell - JKO Handcrafted Woodworking
The more things change ...
We trained hard, but it seemed that every time we were beginning to form up into teams, we would be reorganized. I was to learn later in life that we tend to meet any new situation by reorganizing; and a wonderful method it can be for creating the illusion of progress while producing confusion, inefficiency, and demoralization.
Petronious Arbiter, 210 BC
Going that far to counter vibration shows that they were trying to be really slick but by definition, they'll always be slightly behind the problem frequency. Linear tracking turntables are the same way- the error prompts a response, which always overcompensates, which means that the tonearm is almost always slightly out of alignment. A standard, pivoting tonearm will be truly correct twice, but that's about it. Technology- great, isn't it? Always precise, never exact.I have a customer who wants a new turntable and many of the ones I have seen lately have a base made of MDF, some don't even try to make it look good. Just a painted edge. One had the cheapest cables that I think I have ever seen on a supposedly high-end piece. They were hard-wired- no RCA jacks to make it easy to replace them.
"I cut this piece four times and it's still too short."
Thanks E.,
I had been thinking of veneering a built-up 1-1/2" slab of MDF. I hadn't thought of a mass-filled torsion box....I like that idea a lot. Thanks.
I would say that veneering mdf is not a bad idea. High density mdf is used for most high end speaker cabinets because it is much more 'dead' than any wood. A box filled with acoustic foam or some other sound absorbent material would likely be even better. If you do use solid wood, I believe a dense tropical hardwood would work best. Avoid woods that people make instruments out of... spruce, maple, ash, mahogany to name a few. If you can find a wood that's never been used to make an instrument out of, chances are that's a good pick ;)
"If you can find a wood that's never been used to make an instrument out of, chances are that's a good pick"You mean, like a nice slab of poplar?
"I cut this piece four times and it's still too short."
i guess you picked up on the touch of humor there... although i think bidding opens tomorrow on a fine guarnari del gesu violin with a poplar top. just kidding. I was really thinking more along the lines of jatoba or some other heavy, oily wood. I think i really said all there was to say with the high density mdf idea. That's the industry standard, IMHO most likely the correct choice.
So, if I get the gist of your project, you want to make a piece for each component to sit on in a cabinet or on a shelf, right? Will it have any dampening system (springs, gel, air cushion, etc), other than high mass?I was looking at a piano made of elm. I don't know if you're familiar with the Epiphone 12 string guitars of the '70s but they couldn't be tuned to concert pitch unless silk and steel strings were used because the top would lift and buckle, which meant that they would be just about inaudible when someone else was playing almost any other instrument."I cut this piece four times and it's still too short."
Edited 8/14/2007 9:56 am by highfigh
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