I wanted to use water as another way to extend low frequencies. Due to mechanics contraints I wont use an underwater method. It could be a water filled bag placed in a big pipe. I will tune it as any other 4th order sub than change the amount of water depending on what sound I get...
something like this?
An externally hosted image should be here but it was not working when we last tested it.
Wouldn't placing water in a tube simply act as a port in a bass reflex enclosure?
If so, what would the point of filling it with water be? Wouldn't it simply change the tuning frequency of the system?
I see if you use a completely water tight driver and placing it where both in front and behind it there is water, al la band pass type enclosure. Then the results might be interesting. But it seems to me, now that the thread has become ways of trying to incorperate water in any way to a speaker system. Don't get me wrong, water is cool and using it would be very cool, just don't think that slapping water somewhere will suddenly give you massive bass output.
If so, what would the point of filling it with water be? Wouldn't it simply change the tuning frequency of the system?
I see if you use a completely water tight driver and placing it where both in front and behind it there is water, al la band pass type enclosure. Then the results might be interesting. But it seems to me, now that the thread has become ways of trying to incorperate water in any way to a speaker system. Don't get me wrong, water is cool and using it would be very cool, just don't think that slapping water somewhere will suddenly give you massive bass output.
i think that it can make an interesting sound, because the water has a great inertia and no spider to bring it back to a fixed position. and there is gravity working with the water, also 
possible that the port will work like a passive radiator with a big mass
but still have to fight with the moisture
possible that the port will work like a passive radiator with a big mass
but still have to fight with the moisture
and the evaporation, unless you use a bag, but then it must be water tight and hopefully not affect the sound with it's resonance too much...
Ok lets face it, using water in a sub would be really cool even if there is no benefits. The problem with this is that water tends to wet things. probably using a sealed bag staked in a tube acting as a part of the baffle would be the solution.
like this! I have two MAX PENTIVENT 6.5'' sub laying around here so I got nothing to lose but my time and a big plastic tube.
image
like this! I have two MAX PENTIVENT 6.5'' sub laying around here so I got nothing to lose but my time and a big plastic tube.
An externally hosted image should be here but it was not working when we last tested it.
image
The blue area is the water bag and the grey area is air. Could be interesting. Easy to make and it won't cost much, that's for sure!
PS: I caught the picture before it went off. Geocities and Tripod do not support pictures that last very long.
Better to just upload the picture to the diyAudio server. either that or get some webspace from your ISP that is not Geocities or Tripod.
PS: I caught the picture before it went off. Geocities and Tripod do not support pictures that last very long.
Better to just upload the picture to the diyAudio server. either that or get some webspace from your ISP that is not Geocities or Tripod.
Guss:
Works fine now. It worked fine before, then I came back and it was off. Then it came back on.
I have tried to upload pictures to this site and others from Tripod and Geocities, and I found that they uploaded fine at first, but within a day or two were gone. Something about those free services does not function well for uploading images.
I wonder if they don't do some interrupt on a daily basis, to prevent people from posting these on websites. Saves them bandwidth.
But you are fine, so far.
Works fine now. It worked fine before, then I came back and it was off. Then it came back on.
I have tried to upload pictures to this site and others from Tripod and Geocities, and I found that they uploaded fine at first, but within a day or two were gone. Something about those free services does not function well for uploading images.
I wonder if they don't do some interrupt on a daily basis, to prevent people from posting these on websites. Saves them bandwidth.
But you are fine, so far.
Crude drawings...
Have a look at mine.
I can think of one definite advantage: tuning the PR by ear is now very, very easy! Drone cones require many iterations of "add/subtract weight, test" and with this, you could just put water in or pull water out (with a straw--make sure the tubes are kept clean!) and adjust to taste.
I am worried about large transients sending water flying... perhaps a trap is needed?
Anyway. That's my $0.02.
Have a look at mine.
I can think of one definite advantage: tuning the PR by ear is now very, very easy! Drone cones require many iterations of "add/subtract weight, test" and with this, you could just put water in or pull water out (with a straw--make sure the tubes are kept clean!) and adjust to taste.
I am worried about large transients sending water flying... perhaps a trap is needed?
Anyway. That's my $0.02.
All about wave lenght and water.
water filled tube
speed of sound
This one shows a list of consequences of low freq on body.Effect
water filled tube
speed of sound
This one shows a list of consequences of low freq on body.Effect
Oh yeah? I'm waiting for the first water-filled *magic power cord*. 😉JoeBob said:
Another thing - what will the waterfall response be like? (Ducks for cover).
An externally hosted image should be here but it was not working when we last tested it.
water damping
I started searching around for threads on a sub using water in some way, and had in my head a picture somewhat like the u-bend ksl posted (only I was thinking a big tube filled with water and a smaller tube having the speaker on one end with the other end submerged - same difference). Like ksl said, that might just be a heavy passive radiator-type device (though would it really be "radiating" per se?). Anyway, I had visions of that large mass being pushed up, with gravity subsequently pushing it back down against the speaker (indirectly). Seems like it would interfere with the speaker dynamics too much. Oh, I was about to change direction here, but I just now had a thought - if there were some flexible membrane on the speaker side of the u-tube holding the water below its resting point (below the level of the water on the open side), then the back flow would be limited (because the membrane would be pre-stressed with the weight of the water? ok, I have no idea why my intuition just said that), then the effects on the speaker dynamics would be reduced somewhat.
Ok, now I am confusing myself. I was starting this response to bring up using water to dampen the walls of a sealed enclosure by submerging the enclosure in water. Not sure if that would extend the bass response any (at least by a significant/perceivable amount), but it would help in the dampenig of the enclosure vibrations, and that would be cool. Anyway, I've managed to inundate (ooh, a pun?) my brain with this water stuff, none of which I have any firm grasp on, and I'm gonna go to bed before I blow a gasket.
I'll check back here tomorrow. I haven't completely given up on this whole water idea yet (or oil, hydraulic fluid, jello - whatever). Maybe we can come up with something if we keep this thread going...
I started searching around for threads on a sub using water in some way, and had in my head a picture somewhat like the u-bend ksl posted (only I was thinking a big tube filled with water and a smaller tube having the speaker on one end with the other end submerged - same difference). Like ksl said, that might just be a heavy passive radiator-type device (though would it really be "radiating" per se?). Anyway, I had visions of that large mass being pushed up, with gravity subsequently pushing it back down against the speaker (indirectly). Seems like it would interfere with the speaker dynamics too much. Oh, I was about to change direction here, but I just now had a thought - if there were some flexible membrane on the speaker side of the u-tube holding the water below its resting point (below the level of the water on the open side), then the back flow would be limited (because the membrane would be pre-stressed with the weight of the water? ok, I have no idea why my intuition just said that), then the effects on the speaker dynamics would be reduced somewhat.
Ok, now I am confusing myself. I was starting this response to bring up using water to dampen the walls of a sealed enclosure by submerging the enclosure in water. Not sure if that would extend the bass response any (at least by a significant/perceivable amount), but it would help in the dampenig of the enclosure vibrations, and that would be cool. Anyway, I've managed to inundate (ooh, a pun?) my brain with this water stuff, none of which I have any firm grasp on, and I'm gonna go to bed before I blow a gasket.
I'll check back here tomorrow. I haven't completely given up on this whole water idea yet (or oil, hydraulic fluid, jello - whatever). Maybe we can come up with something if we keep this thread going...
Here's the design I was thinking of last night with the flexible membrane at the bottom. For pure damping, just replace the flexible bottom for a solid piece. Either design should be easy enough to throw together in a coupe hours, using heavy gage trash bags or something for the membrane. Ok, now I'm gonna try to attach the pic...
Attachments
Re: water damping
Yeah water wont amplify anything even if it pass well the lows...I like this dampening concept as water does block most of mechanical vibrations.
It is sure that if we keep this thread alive we could end up with funky stuff like water bandpass but there would be so much mesurement to do just to achieve a proper modeling process...even although we'd get the mesurment right, we would face compliance problems due to the fact that water is not compressible enough as someone said earlier. And where to find waterproof drivers...
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If you chose to do some test with water, you'll see how it behaves under low fq...The spikes really seems to danse forming a sexy configuration over the surface and, if excited enough, it'll flikflak all over the place. It does not reinforce the bass at all and it worsen the mids... Funny isn't it
TDruan said:
Yeah water wont amplify anything even if it pass well the lows...I like this dampening concept as water does block most of mechanical vibrations.
It is sure that if we keep this thread alive we could end up with funky stuff like water bandpass but there would be so much mesurement to do just to achieve a proper modeling process...even although we'd get the mesurment right, we would face compliance problems due to the fact that water is not compressible enough as someone said earlier. And where to find waterproof drivers...
------
If you chose to do some test with water, you'll see how it behaves under low fq...The spikes really seems to danse forming a sexy configuration over the surface and, if excited enough, it'll flikflak all over the place. It does not reinforce the bass at all and it worsen the mids... Funny isn't it
A few thoughts:
--I don't think that the water/air interface is going to transmit sound very efficiently. Think of loud things on or under the water. Take a motorboat, for instance--the kind where the exhaust exits under water. You basically only hear something when a bubble surfaces. All else is an indistinct mumble; they're using the water as a muffler. Whales are reputed to produce sounds well over 150 dB. I think I remember seeing 160-170 dB. But do you hear them from above the water? Of course, whales are scarce hereabouts, so I'm not speaking from personal experience.
--Given the density of water, I'd think that an ordinary driver would have a really hard time displacing the mass. I believe someone mentioned this point earlier. However, take it one step further. Since the driver isn't moving the water much, you're going to turn it up. Lots of power in the voice coil. Burned out voice coil. Since speakers are designed to be air-cooled devices, with the air pumping in and out of the area around the voice coil via the spider, you might be able to simply submerge the entire speaker, filling the coil gap with water, which would then increase the cooling capability astronomically. You're going to need rust proof pole pieces, etc. though.
--The T-S parameters are shot. You'll need a whole new math to calculate proper cabinet volume. Flat response is probably out of the question.
--Jimi Hendrix is said to have taken a driver out of one of his Marshall cabinets (probably a 12" Celestion) and placed it in a bucket of water. He then recorded a song that way. No word on how long the paper cone driver lasted. On the other hand, we're talking about a guy who used lighter fluid and matches on Stratocasters--he wasn't particularly concerned with how long things lasted.
I doubt it was covered as a warranty repair.
Grey
P.S.: So what would you play on such a speaker?
Handel's Water Music, of course!
--I don't think that the water/air interface is going to transmit sound very efficiently. Think of loud things on or under the water. Take a motorboat, for instance--the kind where the exhaust exits under water. You basically only hear something when a bubble surfaces. All else is an indistinct mumble; they're using the water as a muffler. Whales are reputed to produce sounds well over 150 dB. I think I remember seeing 160-170 dB. But do you hear them from above the water? Of course, whales are scarce hereabouts, so I'm not speaking from personal experience.
--Given the density of water, I'd think that an ordinary driver would have a really hard time displacing the mass. I believe someone mentioned this point earlier. However, take it one step further. Since the driver isn't moving the water much, you're going to turn it up. Lots of power in the voice coil. Burned out voice coil. Since speakers are designed to be air-cooled devices, with the air pumping in and out of the area around the voice coil via the spider, you might be able to simply submerge the entire speaker, filling the coil gap with water, which would then increase the cooling capability astronomically. You're going to need rust proof pole pieces, etc. though.
--The T-S parameters are shot. You'll need a whole new math to calculate proper cabinet volume. Flat response is probably out of the question.
--Jimi Hendrix is said to have taken a driver out of one of his Marshall cabinets (probably a 12" Celestion) and placed it in a bucket of water. He then recorded a song that way. No word on how long the paper cone driver lasted. On the other hand, we're talking about a guy who used lighter fluid and matches on Stratocasters--he wasn't particularly concerned with how long things lasted.
I doubt it was covered as a warranty repair.
Grey
P.S.: So what would you play on such a speaker?
Handel's Water Music, of course!
TDruan, I caught the post while the picture wasn't uploaded yet...
If you want to use water as dampening it depends on the way you attach the centerpiece to the rest of the speaker. And you will have to create another suspension at the top edge of the water labyrinth so it does not flikflak over the woofers cone. I'm sure about this idea of flexible membrane as the box wouldn't behave as a closed box neither a ported one, it would be more like a passive radiator or pushpull system. I guess you could take advantage of that configuration using water as stuffing in TLs I think... now I'm dreaming ok
...
Who knows....
If you want to use water as dampening it depends on the way you attach the centerpiece to the rest of the speaker. And you will have to create another suspension at the top edge of the water labyrinth so it does not flikflak over the woofers cone. I'm sure about this idea of flexible membrane as the box wouldn't behave as a closed box neither a ported one, it would be more like a passive radiator or pushpull system. I guess you could take advantage of that configuration using water as stuffing in TLs I think... now I'm dreaming ok
...
Who knows....
Hmm, water is much heavier than air and its SoS is much higher, so it seems to me that filling the cab with it would seriously acoustically mass load the driver, lowering Fs/efficiency and raising Qts a bunch.
GM
GM
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