Thanks Dave. Have you done some accelerometer measurements on different techniques you employed? That is something I would like to play with.
I understand you have a commercial product so tinkering is not just a hobby for you.
I can get away with screwing around and not have to worry about the bottom line 🙂
I have built subwoofer our of concrete. Its still in use by my brother for 30+ years...
Built small boxes out of plaster reinforced by wire mesh. Nothing special.
Made lots of speakers from foam core ready board, layered together with gorilla glue, works great.
Made square box for midrange out of bathroom tiles, worked great.
Rest is usual stuff, ikea cutting boards, small aquarium, birdhouse, all sorts of pipes and sonotubes, you name it.
Built small boxes out of plaster reinforced by wire mesh. Nothing special.
Made lots of speakers from foam core ready board, layered together with gorilla glue, works great.
Made square box for midrange out of bathroom tiles, worked great.
Rest is usual stuff, ikea cutting boards, small aquarium, birdhouse, all sorts of pipes and sonotubes, you name it.
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I agree with Dave's comments. Just makes so much sense to move the speaker basket vibration away to the rear panel. We once did a very "ear opening" exercise by epoxying thick ply to the back of a mid woof and running a bolt to the back panel. Was shocking how much of an improvement it made vs the normal screw attachment to the front baffle.
I may do this next go around. I would try a viscoelastic coupling though. It will transfer some energy to the back panel but it will be attenuated.
Your kidneys will curl-up and die.
Not actually "box", but I have used green insulating foam in a speaker build. I wanted a bass-mid box with an exponential front horn. I did not have fancy tools. I built the box of sheathing ply. I cut-up hard 3" polyu foam with holes to fill the 2'x2'x1' front space. I got in there with a rounded SurForm to work the holes into an exponential horn shape. Then I fiberglassed over.
Up close, it was mildly ugly, even with flat black paint. Out in the audience it had real good "throw" over 400Hz. I was young, and gradually realized that the exponential was not doing much good, and beamy. My next horn was pure pyramidical plywood. Covered a wider swath of the crowd and did not need as much EQ in the 200Hz-600Hz band where the narrower horn perked-up abruptly.
I set-up a super quick and dirty way to look at it on a macro scale. I used my iPhone accelerometer and an app. I played test tones in Spotify.
Not a continuous sweep so I cannot see the resonance peaks but I do see the energy down low like this.
You want to use music as a source of excitation… test tones have too much energy too long to see if potential resonances are excited. The test tones can tell you if there is a potential resonance, but not if it is important.
dave
dave
My current boxes are 3/4" birch ply, peel-n-seel roofing material and 1/2" birch ply braced with Texas Red Oak, but the strangest to me is the super strong concrete a buddy of mine used. You needed a dolly to move the things. He was a very strange dude. His listening room was literally perfectly treated to the point it was absurd.
In the 1980s, Townshend used a plaster-lined steel shell for their Glastonbury speakers, which used Jordan units. This was their last version:
BigEars Audio - townshend
Another company, Electrofluidics, used a polymer for their very heavy and inert cabinets
Lending itself more readily to DIY, the Musician Speaker (a Liverpool University-developed full-range driver from the 1980s) used an interesting cabinet technique. It was constructed of ceramic tiles with cork glued at the edges, holding the tiles together. The cork made the construction airtight and decoupled the tiles from each other. I don't recall if the tiles themselves were damped. The front baffle was formed by the full-range driver, which was mounted on a metal plate.
BigEars Audio - townshend
Another company, Electrofluidics, used a polymer for their very heavy and inert cabinets
Lending itself more readily to DIY, the Musician Speaker (a Liverpool University-developed full-range driver from the 1980s) used an interesting cabinet technique. It was constructed of ceramic tiles with cork glued at the edges, holding the tiles together. The cork made the construction airtight and decoupled the tiles from each other. I don't recall if the tiles themselves were damped. The front baffle was formed by the full-range driver, which was mounted on a metal plate.
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Terracotta ... Off course Italians tried it
Ceramics - Terracotta speakers
quit nice looking actually
In Japan ... recycle car tyres
Here another one ... already thinking to do this for my sons room 🙂
Ceramics - Terracotta speakers
quit nice looking actually
In Japan ... recycle car tyres
Here another one ... already thinking to do this for my sons room 🙂
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