Yes. First of all, forms are needed. Quite robust, but assemble-able/disassemble-able. Concrete has to be made with gravel of random sizes, thickness of walls should be uneven, walls should not be flat, otherwise it will ring like a bell. Then there should be openings for speakers.
It is doable, but can you estimate market demand, so it will cover costs of such forms? I did experiment for myself, so my forms I made from epoxy, and they were quite ugly.
That's why the second experiment I did the opposite way: a first made nice looking boxes from pergo and epoxy, then molded uneven walls inside. The composite that I used was sticking better to my gloves than to the pergo surface. It was not concrete though, because adhesion of concrete to internal walls would be bad... And it shrinks...
I think if to make wooden enclosures, screw many screws in walls inside, hang iron wire between them, then mold concrete inside, it may be doable. But anyway flexibility of forms that concrete allows would be lost. So, disassemble-able forms would be the best way to go.
Costs?
All depends on your appetites. And on your budget. We can think together, what would you like to have...
Mine is much shorter, unfortunately. The next time if I decide to modify it I will definitely build something similar to your picture. And openings will be under the front wall. I re-used the hole in the floor that left from stairs that used to lead to workshop from living room: WAF, so construction is sub-optimal.
If you call me ignorant, with my concrete speakers, please prepare to eat your felt hat!
How long that 1930'th horse will be beaten to death?
An externally hosted image should be here but it was not working when we last tested it.
was not referring to you or about speakers.If you call me ignorant, with my concrete speakers, please prepare to eat your felt hat!
Fibreglass insulation comes very close to what you want. Use the finest stuff available. It will be white and not feel nasty at all.
I'll abstain from the other speaker/horn/carpentry discussions.
Fibers does-not break ? (with the obvious non linearity ?)
Compression/expansion movement of it does not produce noise ?
Frictional forces do not outweigh the restoring forces ?
I use to damp the back chambers of my drivers with fiberglass, but never tried-it in contact with the membrane.
You're right. Robert Oppenheimer and I designed an almost perfect bomb, using a certain amount of an exotic metal. In fact, two pieces of this metal, using a displacement curve i tuned with my friend Euclide de Samos, few years before.
TIP about fiberglass or other damping materials.
Instead of gluing the foils of damping material on the walls of the enclosure, I glue them in the middle (center) of each dimension, separating the volume in 8.
It will operate where the speed displacement of the air is maximum. The standing waves will across the damping material twice. So, it will increase the damping. And you can use less damping volume material, means more freedom... More "live" sound, less dull.
While i let a whole in the center of the horizontal and vertical foils parallel to the displacement axis of the membrane, i glue the foil "waterproof" between the loudspeaker and the back of the enclosure. This foil act like a damping wall during big transients low displacements of the membrane, and you can see the foil moving with kick drums. It gives more 'Speed" and more dump to your bass sound.
Instead of gluing the foils of damping material on the walls of the enclosure, I glue them in the middle (center) of each dimension, separating the volume in 8.
It will operate where the speed displacement of the air is maximum. The standing waves will across the damping material twice. So, it will increase the damping. And you can use less damping volume material, means more freedom... More "live" sound, less dull.
While i let a whole in the center of the horizontal and vertical foils parallel to the displacement axis of the membrane, i glue the foil "waterproof" between the loudspeaker and the back of the enclosure. This foil act like a damping wall during big transients low displacements of the membrane, and you can see the foil moving with kick drums. It gives more 'Speed" and more dump to your bass sound.
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An other tip is to flatten the loudspeakers impedance.
If good monitors manufacturers think to compensate the inductance impedance of the coils, very few of them care to correct the motional impedance at the resonance. Is it easy to do, with an inductance, a cap and a resistance. Do-it with your loudspeaker at free air. (according to its Thiele & Small parameters).
You will object that it will give strange results, when a bass reflex changes the impedance curve near the resonance, as well as the resonance frequency ?
Just try-it, and you will be surprised to see the flatten remains correct. Jut you can adjust the value of the resistance, if your impedance curve goes too low where the events are tuned to resonate.
The benefit ?
They are two.
First, with a flat impedance of your enclosure, your amp will have to deal less with voltage/current incoherences.
Second, it will dump your speaker in an unbelievable way: hit the membrane of your bass speaker in your enclosure. You can here the characteristic heavy "BOUM BOUM" of the resonance. With the motional impedance compensation, it wil turn in a light "kock kock" damped sound, very "fast", where resonance is at very low level and you can hear the material of the membrane.
Enjoy the difference, with a much better separation between basses and kick drums, better transients, and a feeling of increased speed and dynamic with less weight. You will feel that your enclosure has wined 1/2 octave down in the low frequencies.
If good monitors manufacturers think to compensate the inductance impedance of the coils, very few of them care to correct the motional impedance at the resonance. Is it easy to do, with an inductance, a cap and a resistance. Do-it with your loudspeaker at free air. (according to its Thiele & Small parameters).
You will object that it will give strange results, when a bass reflex changes the impedance curve near the resonance, as well as the resonance frequency ?
Just try-it, and you will be surprised to see the flatten remains correct. Jut you can adjust the value of the resistance, if your impedance curve goes too low where the events are tuned to resonate.
The benefit ?
They are two.
First, with a flat impedance of your enclosure, your amp will have to deal less with voltage/current incoherences.
Second, it will dump your speaker in an unbelievable way: hit the membrane of your bass speaker in your enclosure. You can here the characteristic heavy "BOUM BOUM" of the resonance. With the motional impedance compensation, it wil turn in a light "kock kock" damped sound, very "fast", where resonance is at very low level and you can hear the material of the membrane.
Enjoy the difference, with a much better separation between basses and kick drums, better transients, and a feeling of increased speed and dynamic with less weight. You will feel that your enclosure has wined 1/2 octave down in the low frequencies.
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I had a chance to listen to Sophia, Watt/Puppy and Maxx, longtime. Frankly, I was not amazed by Watt/Puppy. They have very strong "character" and they are far from neutrality. I liked smaller Sophia better, for more compact sound. If I wanted a big sound, I preferred Maxx, the sound is bigger and more neutral than that of Watt/Puppy.
Nice description -- havent heard the benefits described that way and now i am curious to try it on my commercial systems. Thx - RNM
I have an early WATT speaker system that I purchased to replace the original WATT-PUPPY that Dave Wilson gave me in 1987 or so. Unfortunately, it was destroyed in a firestorm 21 years ago, almost to the day, and I went without a decent speaker for a year or two. I wanted my WATT's back, so I bought a pair, used, and I have never regretted it. I don't necessarily like the more recent WATT's for some reason. Probably the tweeter. I am still friends with Dave Wilson, but we have been out of touch for years. I too am ASTOUNDED that his best speakers now cost $200,000, and I was not that impressed with them at a listening session a few weeks ago.
I know that he 'throws money' at his speakers, spares them no cost, but I want to be AMAZED when I hear them, not just satisfied.
About 30 years ago, Dave Wilson brought his WAMM speaker system to a CES. I heard that demo and I was AMAZED. And I told him so, at the time. I know a little bit more about the design of his speakers, but I am not privileged to share that info. There is high technology in them.
I know that he 'throws money' at his speakers, spares them no cost, but I want to be AMAZED when I hear them, not just satisfied.
About 30 years ago, Dave Wilson brought his WAMM speaker system to a CES. I heard that demo and I was AMAZED. And I told him so, at the time. I know a little bit more about the design of his speakers, but I am not privileged to share that info. There is high technology in them.
Please keep-me informed of your subjective conclusions.
This same helps a lot to calculate and tune filters with middle and trebles, of course, and can remove some tonal characters.
It is the first thing i do before to mount any new speaker.
It has an other benefit: If your enclosure has a flat impedance, it is less sensible to any serial resistance or damping factor of the amp, regarding response's curve modification.
So , you can avoid exotic cables, use those that conduct electricity and, with the saved money, have a nice dinner with those nice virgins previously employed to cryogenic them in liquid helium.
Did-he use a brand new compressed Ferrari for each chassis, plain diamond machined cones, and gold ribbons for the moving coil's ?
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I dont doubt that you get results with this if you say so, but nevertheless it sounds
rather counter intuitive.
One might argue that where has been an impedance peak in free air (which you now
lower or flatten), might be an impedance minimum once the speaker is mounted
in a ported box.
What is the theory behind that ? How does this work (in contrary to the more
common method of flattening the mounted speaker and frequency network) ?
No Mr. Wilson probably drives a Ferrari or similar expensive car.
Or maybe a Bentley. Your avatar, I'm honored!
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