well, we all know how subs work, using an electromagnet to pushpull a driver. if someone were to take the driver out and leave the magnet and shaft, it would be possible to attach it to a fairly large rubber-band so it would pulsate back-and-forth. testing this myself i reaching down to about 3hz with minor strumming.
how could this be implemented to produce real "sound" instead of just vibrations?
how could this be implemented to produce real "sound" instead of just vibrations?
it wouldn't be one band. i was thinking about one band for each freq point under 17 hz. each of them would be crossedover to accept only its certain frequency point. i have contacted TB and they'd sell the electromagnet and shaft to me for 8 dollars. 8*17=$136 + free rubber bands. Not to shabby for a sub that can go that low vs. the 13000 dollar eminent tech fan sub.
You would need a resonator to amplify the sound and better couple it to the air.
This might help
http://www.phys.unsw.edu.au/~jw/Helmholtz.html
Check out the part about the Guitar
This might help
http://www.phys.unsw.edu.au/~jw/Helmholtz.html
Check out the part about the Guitar
really cool idea, but...
I think the question about damping is important.
Methinks you could get it to vibrate, and could maybe get some sound out by coupling to air, but if it (like most rubber bands) keeps vibrating for ~3 seconds it will be pretty "sloppy".
If I remember my physics correctly, you're essentially building a series of very high Q resonators.
I think the question about damping is important.
Methinks you could get it to vibrate, and could maybe get some sound out by coupling to air, but if it (like most rubber bands) keeps vibrating for ~3 seconds it will be pretty "sloppy".
If I remember my physics correctly, you're essentially building a series of very high Q resonators.
its going to be pretty hard to make a crossover that passes only 17 hz and not 16 or 18 at all.
you would need about 50 or more of them. each with separate amplifier.
it would be pretty horrid because the width and twisting of the band would also cause sympathetic resonance at different frequencies.
take a rubber band and "boing" it and look at the wave on ocilloscope or record it and look at it on the PC. its not much of a pure sine wave.
you would need about 50 or more of them. each with separate amplifier.
it would be pretty horrid because the width and twisting of the band would also cause sympathetic resonance at different frequencies.
take a rubber band and "boing" it and look at the wave on ocilloscope or record it and look at it on the PC. its not much of a pure sine wave.
PUSHING STRING
You can't push an ordinary rubber band.
So you'd have to attach it to a big, BIG, tight, diaphragm like that of a bass drum, only real BIG. A suitable material might be vinyl - it has a sg of @1.3 and comes in lots of thicknesses so you might get some damping.
A diaphragm say, 6' X 6' or 8' X 6' or ...
Put it in a frame.
Hang it on the wall.
Maybe put the driver(s) in the wall.
Paint a picture on the diaphragm.
Now you have a stealth sub-sub woofer.
How much "excursion" does 36 ft^2 need to produce significant sound pressure?
You can't push an ordinary rubber band.
So you'd have to attach it to a big, BIG, tight, diaphragm like that of a bass drum, only real BIG. A suitable material might be vinyl - it has a sg of @1.3 and comes in lots of thicknesses so you might get some damping.
A diaphragm say, 6' X 6' or 8' X 6' or ...
Put it in a frame.
Hang it on the wall.
Maybe put the driver(s) in the wall.
Paint a picture on the diaphragm.
Now you have a stealth sub-sub woofer.
How much "excursion" does 36 ft^2 need to produce significant sound pressure?
That's because they didn't have much of a baffle. But they have other merits
I have a new concept. Let's mount the wall on rubber, and vibrate the wall. Trouble with that is the elasticity of rubber varies with temp.
On a positive note, ideas should be put up by those with imagination, otherwise nothing new is developed. What would we be doing now if Thomas's mother didn't get sick, and was not operated on under candlelight, or, if Thomas never thought of recording sound?
The electro magnetic speaker as we know it has been with us a long time. ESLs, Magnaplaner, plasma, ribbon, and a few other designs have popped up, but not replaced the good old magnet/coil/cone combination. Does that mean we have given up on an alternate method?
With the advent of digital sound, I think the next step would be to drive cones, or whatever, digitaly. i.e. d to a conversion in the driver itself. If we can control CNC machinery to very high acuracy, why cant we control a sound radiator?
I have a new concept. Let's mount the wall on rubber, and vibrate the wall. Trouble with that is the elasticity of rubber varies with temp.
On a positive note, ideas should be put up by those with imagination, otherwise nothing new is developed. What would we be doing now if Thomas's mother didn't get sick, and was not operated on under candlelight, or, if Thomas never thought of recording sound?
The electro magnetic speaker as we know it has been with us a long time. ESLs, Magnaplaner, plasma, ribbon, and a few other designs have popped up, but not replaced the good old magnet/coil/cone combination. Does that mean we have given up on an alternate method?
With the advent of digital sound, I think the next step would be to drive cones, or whatever, digitaly. i.e. d to a conversion in the driver itself. If we can control CNC machinery to very high acuracy, why cant we control a sound radiator?
Shakers...
buddy of mine was in Montreal in the 80's and was with another friend who was an engineer with the city. They were looking at a sound rig being set up for a concert (dont recall the venue). My bud asked where the subs were. They were then shown a number of big shakers (think it was five units) on which the modular stage was mounted. These are the kind that they use to test cars and trucks. After the engineer had crunches some numbers (area of stage and xmax) he told the rig owner that they could not use the sub in that building and an alternate box system had to be brought in. Tom Danley would be up on this kind of thing he knows how to make bass loud. Regards Moray James.
buddy of mine was in Montreal in the 80's and was with another friend who was an engineer with the city. They were looking at a sound rig being set up for a concert (dont recall the venue). My bud asked where the subs were. They were then shown a number of big shakers (think it was five units) on which the modular stage was mounted. These are the kind that they use to test cars and trucks. After the engineer had crunches some numbers (area of stage and xmax) he told the rig owner that they could not use the sub in that building and an alternate box system had to be brought in. Tom Danley would be up on this kind of thing he knows how to make bass loud. Regards Moray James.
Hi Moray. Interesting. I know of the "shakers" you describe. They are used here to test truck suspension. Vibrate each wheel at about 5 hz to make sure it wont fall apart on our highways. (The 5 or so hz represents our road surface at 100Km/h.)
More seriously. I watched a recording studio being built many years ago. It started with a hole in the concrete slab. A smaller slab poured in that hole with a 100mm gap. A layer of foam rubber, then another slab on that. The entire room was floating on rubber. That was to stop road vibration. Hang on, I'm back to roads again.
That was mid 70s. If I had of said "great concept for a sub" I would have been escorted off site. Now that same year, Bob Dylan toured Australia. One of his sound engineers told me that BD used custom foldbacks - he liked to feel the sound, and stood on them.
It was in that era, subs first came under my attention. Altec's coffee table was the first I noticed.
There must be another way of moving air or the floor at subsonic or bass frequencies. Thinking.
More seriously. I watched a recording studio being built many years ago. It started with a hole in the concrete slab. A smaller slab poured in that hole with a 100mm gap. A layer of foam rubber, then another slab on that. The entire room was floating on rubber. That was to stop road vibration. Hang on, I'm back to roads again.
That was mid 70s. If I had of said "great concept for a sub" I would have been escorted off site. Now that same year, Bob Dylan toured Australia. One of his sound engineers told me that BD used custom foldbacks - he liked to feel the sound, and stood on them.
It was in that era, subs first came under my attention. Altec's coffee table was the first I noticed.
There must be another way of moving air or the floor at subsonic or bass frequencies. Thinking.
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