http://www.michaelgreenaudio.net/platforms
Love Platforms!
DIY speaker isolation base for a wood floor
http://www.michaelgreenaudio.net/platforms Love Platforms! |
My dual-layer iso platform Nirvana employs two very heavy masses 18x18 like granite or bluestone and two layers of springs. You can achieve extremely low resonant frequencies Fr with this set up, circa 1.0 Hz. Hel-loo! Total cost you ask, about $100. You supply the granite or bluestone. Cannot beat with stick. |
Right. So there are two issues here, the speaker vibrating and the floor acting as a sounding board. In geoFFkait's example he is isolating the floor from everything above 1 Hz. So the floor is being isolated nicely. But, unfortunately the speaker is free to vibrate at all frequencies above 1Hz. Any vibration of the speaker is distortion. Some new designs like the Kef Blades and Magico subwoofers use drivers on opposite sides of very stiff enclosures so their forces cancel. This prevents the enclosure from vibrating as a whole. The best way for us to deal with both problems is to have a stiff well dampened floor. Concrete is ideal. A wood floor has to be very stiff then dampened with padding and carpet. The best way to keep the enclosure from vibrating is to spike it to a stiff well dampened floor. Force cancelling woofers like in the Kef Blades are ideal. Good work geoFFkait you have succeeded in making a bass distortion machine. |
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Check out the Herbie footer/isolation. This is what I use. https://herbiesaudiolab.com/collections/loudspeaker-rack-decoupling-and-isolation/products/cone-spik... ozzy |
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"I always thought you wanted to couple your speakers to the floor (with spikes). Now it is best to decouple them?" There is no such thing as decoupling in audio. That's just a talking point from those who are dampening. Once you put your speakers in a room all the physics of that room and the speaker becomes one and the same. |
If there was no such thing as decoupling we never could have detected and observed gravity waves. The only challenge for decoupling for audio is how many directions 🔜 🔚 🔝 you can decouple from and how low a resonant frequency Fr you can achieve for each direction. My airspring Nimbus of yore, for example, decoupled in all six (count em!) directions with Fr as low as below 1 Hz. The lower you go the higher you fly. In other words decoupling is not (rpt not) synonymous with damping. Damping techniques on the other hand 🖐 cannot affect extremely low freqjencies of vibration. That’s why mass-on-spring devices must (rpt must) be used for vibration in the range 0-20 Hz. You can also think of iso devices as anti gravity devices, if that helps. By the time you get to 20 Hz you’re already 95% effective. So, where’s the beef? 🍔 |
Me, I need to move mine: Real Heavy Speakers on 3 Wheels. 3 = more weight per wheel than 4, and 3 is always self-leveling. Current big box, 3 way, 15" woofer, horn mid, horn tweeter, I am guessing between 150-200lbs ea. 3 wheel caution. I have blocks just above the floor at the rear corners, the edge of the centered 3rd wheel, to prevent tipping, especially as they are tilted back as well. If it tips in any direction, the raised corner blocks then hit the floor, preventing further tip. tilt: a concealed block at the front above the front 2 wheels tilts the speaker back, both time alignment and altering angle of reflections off the floor and ceiling. Move to precise listening position, or push out of the way (some or a lot). I've done the isolation/spike thing, with these, other 120lb speakers, and lighter ones. With enough weight I like wheels. My JSE Model 2's, 125 lbs each, came with factory wheels. https://www.google.com/search?q=jse+model+2&sxsrf=ACYBGNSrOb458uz5Jwdm0yyn06W5XsOqNw:1576775349791&tbm=isch&source=iu&ictx=1&fir=5zrM1YT0ijckLM%253A%252CuIXJGK1HDmXTvM%252C_&vet=1&usg=AI4_-kQ2cALZwZ45VVbDYcUebQJmdxiZWQ&sa=X&ved=2ahUKEwjNlfX0mcLmAhVrUN8KHeWzDPMQ9QEwAHoECAcQBg#imgrc=5zrM1YT0ijckLM: Tried em, spiked em, no improvement obvious to anyone, so I changed 4 wheels to 3 on them. They had their own time aligned slanted front panel, and I just carefully avoided tipping. Loved them for many years, Son Chris has them now. |
"There is no such thing as decoupling in audio. That’s just a talking point from those who are dampening (1). Once you put your speakers in a room all the physics of that room and the speaker becomes one and the same (2)." 1: We are not dampening (to make wet ;-), we are damping (reducing the physical vibrations is a solid material). Those who contend hi-fi components are themselves musical instruments (a silly contention ;-) and should be left to resonate, are against damping. Those of use who don’t consider components music makers but rather music reproducers, are for it. 2: We need to make a distinction between the physical mass of a pair of loudspeakers from the acoustic sound they propagate with a room. Those speakers are ACOUSTICALLY inseparable from the room (the room is to the speakers as the speaker enclosures are to rear output of their drivers). That does not mean the speakers cannot be PHYSICALLY isolated from the surface of the room upon which they sit. Whether or not you want to separate them is another matter. @blueranger, GK’s springs are ridiculously-low priced compared with all similar products (the Townshend Audio Seismic line, for instance), and a great way to find out if you prefer decoupling to coupling (spikes, cones) of your speakers. But remember, as Geoff has correctly stated here numerous times, spikes and cones provide isolation down to a not-very-low frequency (around 10Hz), and coupling below that frequency. And that frequency is not a single number, but rather the corner frequency of a 1st order (6dB/octave) low pass filter. |
Hi Blue Springs are a great tool when voicing your system. Once you start using them you might find other materials that you like the sound of better than aluminum, rubber and granite. Steve's invention of the Tip Toe was also revolutionary and was the beginning of the audio cone. I prefer the sound of Brass and Zinc and even mild steel as being more tuneful especially use with wood materials. |
michaelgreenaudio1,005 posts12-20-2019 6:14am So bdp24 thinks that you can place something in a room without it touching anything. Nice trick lol. mg >>>>Ah, magnetic levitation! Now you’re talking, Michael. |
michaelgreenaudio Springs are a great tool when voicing your system. Once you start using them you might find other materials that you like the sound of better than aluminum, rubber and granite. >>>>>Agree. Springs are a great tool. That’s because they’re great isolators. Use them under amps, use them under power supplies, use them under speakers, use em under subwoofers, use em under CD players. The more springs you use the lower the system mass. The more springs you use the more you can hear! Hey, how ‘bout little mag lev isolators for cables and power cords?! 🤗 |
Not on Earth anyway. exactly, thank you "everything affects everything else" you and Geoff head to another planet with different results let us know you two think you can play something in a room decoupled from that room let us know you two think you can isolate audio in an active room let us know oh and good luck, you will have accomplished something no one else in audio ever has |
The best isolation I have ever witnesses was Audiogon member folkfreak’s Herzan active isolation platform under his turntable. Very effective, and unfortunately very expensive. Here's a real talking point: "low mass". My Music Reference RM-10 Mk.2 is a real nice little tube amp, but that niceness is not the result of it's low mass (it weighs only 12 lbs.). My RM-200 Mk.2 also sounds good, and it's a fairly hefty 52 lbs. I won't be selling it and buying a mass-market receiver from the "Golden Age Of High End Audio", the 70/80/90's. More silliness. Low mass in a loudspeaker driver IS a factor in it's sound quality, for the obvious reason: That mass is moving. The faceplate and chassis of my EAR-Yoshino pre-amp are the heaviest (20 lbs.) of any I've owned, and it's the best sounding as well. I guess in spite of it's mass ;-) . |
1. Start with 4 aluminum cones. I used some old Mod Squad Tip Toes. No need for all that, or any expensive hifi products, just use 4 of these these under each speaker, Sorbothan pads it’s the best vibration isolater , they are 70 duro the heaviest duty and will support and isolate your speaker. https://www.ebay.com/itm/4-LARGE-SORBOTHANE-DISC-CIRCLE-FEET-PAD-2-5x0-5in-64x12mm-SILENT-PC-AMP-FIRM-70D/372429364953?epid=1031478471&hash=item56b6851ed9:g:O04AAOxycmBS70F6 Cheers George |
I have always found this to be a fascinating subject. Partway agreeing with some of the ideas here, I tried something a bit different. First of all, the speakers that built have very heavy duty outriggers. I did this because the speakers that I built were just a bit narrow at 12" wide. I found Sorbothane 50 thick pads that were mounted to 1/4" bots. That made it easy to just screw them into the outriggers. Knowing that Sorbothane has issues on many surfaces, I happened to find furniture cups with a bunch of small plastic spikes (probably meant for carpet), that neatly fit over the bottom edge of the Sorbothane. End result is a maybe yes maybe no outcome. When I was still a bachelor, I thought about metal screws holding the speakers tight to the floor... and round we go. |
May I suggest Fastenal for springs (or any number of other industrial suppliers). They have literally hundreds of options and they are dirt cheap. Many diameters, lengths, wire size, and very inexpensive. That let’s you much better match your component to the spring as opposed to a few limited options. delkal72 posts12-18-2019 10:14pmI always thought you wanted to couple your speakers to the floor (with spikes). Now it is best to decouple them? There is no right answer delkal, as it depends on your floor and speakers. Those claiming one answer is always right .... and like a broken clock. They are exactly right every once in a while. Concrete floors and a speaker cabinet not as stiff as one would like, then odds are better to couple to the floor for damping. A springy floor and you likely want to decouple it, but not necessarily. If the cone is going one way, then the cabinet wants to go the other way. Georgehifi makes a point about sorbathane. It is one of the best energy absorbing substances and absorbing energy you don’t want to turn into sound is a good thing (this is what sand does as well) ... and what the op is trying to accomplish with neoprene. I would suggest sorbathane instead, though more expensive. The 70D linked would be too dense as a set of 4 for almost any speaker. 50D which they appear to also sell or even 30 would be more appropriate. |
The more you try to store energy the worse things get. It’s a vicious cycle. Sorborhane, as fate would have it, is one of the worse materials ever foisted on naive and gullible audiophiles, right up there with SONEX and lead. It seems like such a good material - not too hard, not too soft. That’s why spring based systems and extremely hard cones like NASA grade ceramics of Golden Sound cones rule the night. They don’t store energy. |
Spring based systems don't store energy .... Ooooookay.
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Feel free to address 1 to 4 in a cogent manner. |
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If anyone would like a quick refresher on springs, mass, and resonance, they may enjoy this: https://www.newport.com/t/fundamentals-of-vibration Newport is a scientific instruments company mainly focused in anything related to optics and light and anything related to that, including vibration control. i.e. a spring that is 1.5" free length, 1 inch compressed with a 10lb load will have a C of about 0.00029 meters/newton, and a resonant frequency with a 10lb (4.5 kg) load of 4.4Hz. That (w) is radians/second in the link. |
Ironically (perhaps) Minus K is actually the modified “audiophile” version of the Newport Corp Sub-Hertz Platform of yore. Also ironically, the Vibraplane, the first high end iso stand is also based on a Newport iso stand, a table top microscope stand. But what is missing, if I can be so bold, is the “black art” of isolation necessary to get the best performance out of isolation systems. It’s not all numbers, guys! In the beginning there were only four iso stand manufacturers - Townshend, Brightstar, Vibraplane and your humble scribe, and mine was the only one with a sub Hertz performance. Of course, there should be a tip of the hat to LIGO project - the grand wazoo of isolation ever since it detected gravity waves, the amplitude of which are on the order of an atomic nuclear. Also, of some interest to the student is the fact that the actual operating principle of the Minus K stand is “negative stiffness,” a much more complex principle than simple mass-on-spring employing stiff members and springs. Get it? Negative K? |