But it looked good in theory...
Perhaps we can make a product that is mostly air core but gives the end user an option to fill the voids with sand. Would probaby negate the low-weight aspect 🙁
I am experimenting with other ideas. Here is a mock-up using soda cans glued together. Perhaps the rest of a cabinet can be cardboard but pretty sure the heavy driver will need to be mounted on a piece of board like the current base shown.
Even more amazing is that of three cats, no one has knocked it down in twelve hours !
Perhaps we can make a product that is mostly air core but gives the end user an option to fill the voids with sand. Would probaby negate the low-weight aspect 🙁
I am experimenting with other ideas. Here is a mock-up using soda cans glued together. Perhaps the rest of a cabinet can be cardboard but pretty sure the heavy driver will need to be mounted on a piece of board like the current base shown.
Even more amazing is that of three cats, no one has knocked it down in twelve hours !
Attachments
Found some new info on honeycomb pallets, not all of it favorable to my hare-brained schemes 🙂
http://www.solutionsforwood.com/_docs/reports/PalletTrends09.pdf
"...paper pallettes lack stiffness with flexible loads..." -> a disadvantage (duh!) since I daresay that air in the subwoofer is a most flexible load! I say, old chap...
Pallets for Export - Paper Pallets Offer Benefits for Container and Air Freight | Packaging Revolution
Quote:
"...benefits [of paper pallettes] include:
Price that can be comparable to wood pallets [so, perhaps no cheaper for our uses than plywood?]
On the other hand:
ISPM-15 compliant wood pallets can be cheaper [well is it or isn't it!?!?]
Paper pallets do not match strength and stiffness of comparable timber pallets (in order to rack them, IKEA had to upgrade their warehouse racking to fully support them
Not durable
Susceptible to failure due to moisture (unless coating added)
[those items are relevant to speaker-buildiing, ya?]
http://www.solutionsforwood.com/_docs/reports/PalletTrends09.pdf
"...paper pallettes lack stiffness with flexible loads..." -> a disadvantage (duh!) since I daresay that air in the subwoofer is a most flexible load! I say, old chap...
Pallets for Export - Paper Pallets Offer Benefits for Container and Air Freight | Packaging Revolution
Quote:
"...benefits [of paper pallettes] include:
Price that can be comparable to wood pallets [so, perhaps no cheaper for our uses than plywood?]
On the other hand:
ISPM-15 compliant wood pallets can be cheaper [well is it or isn't it!?!?]
Paper pallets do not match strength and stiffness of comparable timber pallets (in order to rack them, IKEA had to upgrade their warehouse racking to fully support them
Not durable
Susceptible to failure due to moisture (unless coating added)
[those items are relevant to speaker-buildiing, ya?]
Last edited:
If money (or sanity) is no object, we also offer you...
And to really go into "left field" here is some carbon fibre options:
Carbon Fiber Applications - Robotics, UAV, Sports Equipment, Musical Instruments
I mean, what mere mortal could resist the lure of a quasi-isotropic laminate"? For crying out loud they even have carbon-faced foam board (there is your good sound-absorber so they claim). Even furniture made with a core of the DIY sub-builder's favorite, Baltic birch.
The main downside is no doubt the price, as Cathy in the comics would say "Ack!" (Bloom County's Bill the Cat said the same, but he was a more laid back dude...)
And to really go into "left field" here is some carbon fibre options:
Carbon Fiber Applications - Robotics, UAV, Sports Equipment, Musical Instruments
I mean, what mere mortal could resist the lure of a quasi-isotropic laminate"? For crying out loud they even have carbon-faced foam board (there is your good sound-absorber so they claim). Even furniture made with a core of the DIY sub-builder's favorite, Baltic birch.
The main downside is no doubt the price, as Cathy in the comics would say "Ack!" (Bloom County's Bill the Cat said the same, but he was a more laid back dude...)
Attachments
9 lb sub woofer (mostly weight of four 6.5 in drivers - rest is 2 lbs of foam core) - 94 dB efficiency and reaches only modest 115 dB but sounds great.
http://www.diyaudio.com/forums/full-range/247598-nautaloss-ref-monitor-6.html#post3750525
I think the honeycomb cardboard is an excellent candidate for a lightweight tapped horn sub. If you want put roofing tar-faced sealer sheets in between two layers of the honeycomb for constrained layer damping.
Constrained layer atop of the honeycomb panels.
Have been playing with some Contact Brand "Grip Premium" shelving mats, HD Con-Tact 18 in. x 4 ft. Black Premium Grip Shelf Liner, 6 Per Pack-04F-C6U51-06 at The Home Depot
This is a medium density vinyl(?) foam mat that is ~2.3mm thick and available in multiple colors and in single rolls for $6 at the store. They have similar w/ embossed pattern, skip them, or the lesser foam bead types, not worthy of attention.
A single layer between two sonotubes (sakrete brand) unadhered, using pressure only, supplied by the outer layer has reduced enclosure resonances by >20dB. That paper transparency issue muted.
Hoping to get in a few outdoor measurements between the seabreezes today
Have been playing with some Contact Brand "Grip Premium" shelving mats, HD Con-Tact 18 in. x 4 ft. Black Premium Grip Shelf Liner, 6 Per Pack-04F-C6U51-06 at The Home Depot
This is a medium density vinyl(?) foam mat that is ~2.3mm thick and available in multiple colors and in single rolls for $6 at the store. They have similar w/ embossed pattern, skip them, or the lesser foam bead types, not worthy of attention.
A single layer between two sonotubes (sakrete brand) unadhered, using pressure only, supplied by the outer layer has reduced enclosure resonances by >20dB. That paper transparency issue muted.
Hoping to get in a few outdoor measurements between the seabreezes today
Torlyte from Russ Andrews (yes I know in some circles that is blasphemy!)
This is a hollow material built from thin strips of wood assembled into a matrix with veneer top and bottom.
Torlyte : Russ Andrews,Hi-fi Accessories,Home Theatre Accessories,cables,mains,speakers,interconnects,speaker cables,mains accessories, turntable accessories, cd accessories...
This is a hollow material built from thin strips of wood assembled into a matrix with veneer top and bottom.
Torlyte : Russ Andrews,Hi-fi Accessories,Home Theatre Accessories,cables,mains,speakers,interconnects,speaker cables,mains accessories, turntable accessories, cd accessories...
xrk, if I haven't said it before, "Well done" for your foam sub! I've read the thread (part of) and it sounds (1) inexpensive and (2) very time intensive. Speaking for myself only, of course, I know what "DIY" stands for but there is no requirement as to how much "doing" is required 🙄
My name is Soldermizer, and I'm a DIY-holic...
I just got back from Lowe's with a some more items to experiment with. I am too lazy to even do something I have with materials on hand (cut a hole in the 24x24" square for mounting a speaker) and instead am going to try something even flimsier (which would be nearlly everything...) DIY "composite" which is a fancy name for two layers of scrounged cardboard over a lattice of (?) I have not found the worst thing yet (paper honeycomb) but next-best: I got a bunch of furring strips at store, only about $1 for 8 ft. i will try glueing these to cardboard or ...
I've priced ready-made "real" lattices or panel innards and they are not really cost-effective. Until I noticed in my closet I had one of these:
6 Cube Organizer | ClosetMaid
And wondered "Hmmm...." would definitely be sturdy, quite possibly stiff as the center of a cardboard sandwich. The basic square/cube is 14" so an easier fit for 12" or smaller drivers (duh!). To do a 15" shall require a bit more trickery. No law says you would have to use the supplied plastic connectors, probably wouldn't want to anyway. If a sturdy way can be found to join them, then one could make an arbitrarily large enclosure.
If you like rodents you can also do this:
Kibbles 'N Knits: DIY Guinea Pig Cage
I actually tried this (had the cube shelves on hand already) but found it inconvenient. So I let my little biting things have their own room and everybody's happy 🙂
I will post results on the next experiments. (Do you ever wonder why there are experiments but not expeppermints? Why "excrement" isn't the opposite of "increment"?) 🙂
My name is Soldermizer, and I'm a DIY-holic...
I just got back from Lowe's with a some more items to experiment with. I am too lazy to even do something I have with materials on hand (cut a hole in the 24x24" square for mounting a speaker) and instead am going to try something even flimsier (which would be nearlly everything...) DIY "composite" which is a fancy name for two layers of scrounged cardboard over a lattice of (?) I have not found the worst thing yet (paper honeycomb) but next-best: I got a bunch of furring strips at store, only about $1 for 8 ft. i will try glueing these to cardboard or ...
I've priced ready-made "real" lattices or panel innards and they are not really cost-effective. Until I noticed in my closet I had one of these:
6 Cube Organizer | ClosetMaid
And wondered "Hmmm...." would definitely be sturdy, quite possibly stiff as the center of a cardboard sandwich. The basic square/cube is 14" so an easier fit for 12" or smaller drivers (duh!). To do a 15" shall require a bit more trickery. No law says you would have to use the supplied plastic connectors, probably wouldn't want to anyway. If a sturdy way can be found to join them, then one could make an arbitrarily large enclosure.
If you like rodents you can also do this:
Kibbles 'N Knits: DIY Guinea Pig Cage
I actually tried this (had the cube shelves on hand already) but found it inconvenient. So I let my little biting things have their own room and everybody's happy 🙂
I will post results on the next experiments. (Do you ever wonder why there are experiments but not expeppermints? Why "excrement" isn't the opposite of "increment"?) 🙂
Last edited:
I was framed!
The IKEA method is called "Board on frame" (Why? I would think: board made from frame. But whatever...) I have no idea whether this will work (my general avoid-sound-construction-practices approach) but today's big idea was "why can't I use a frame (be it wire mesh, or even a rickety wooden structure)? Leave aside the arguments people have made that the panels need to be constrained surfaces (which is?) I guess airtight, stiff and (this was the hard one to find with hollow panels!) sound-proof. The minimal requirement for a sub enclosure should be that it will of course support the driver. But the other panels need not be load bearing. So perhaps cling wrap cemented to chicken wire will work after all. No wait, that's number 13 on the to-do list
It does just occur to me that with tonight's "sandwich" I have probably effectively made a giant kazoo: I have widely-spaced furring strips (intended to be the driver's suport) but too much hollow space.
"I deny the charges of robbing a liquor store. I deny the charges of carrying a .44. I deny the charges of vagrancy too. But when the proscuting attorney poured whiskey on my head turned me around to face the jury and said 'Convict this man, he's drunk!" What could I do? I was framed! I never do nothin' wrong, but I always get the blame!" -- Little Feat
The IKEA method is called "Board on frame" (Why? I would think: board made from frame. But whatever...) I have no idea whether this will work (my general avoid-sound-construction-practices approach) but today's big idea was "why can't I use a frame (be it wire mesh, or even a rickety wooden structure)? Leave aside the arguments people have made that the panels need to be constrained surfaces (which is?) I guess airtight, stiff and (this was the hard one to find with hollow panels!) sound-proof. The minimal requirement for a sub enclosure should be that it will of course support the driver. But the other panels need not be load bearing. So perhaps cling wrap cemented to chicken wire will work after all. No wait, that's number 13 on the to-do list
It does just occur to me that with tonight's "sandwich" I have probably effectively made a giant kazoo: I have widely-spaced furring strips (intended to be the driver's suport) but too much hollow space.
"I deny the charges of robbing a liquor store. I deny the charges of carrying a .44. I deny the charges of vagrancy too. But when the proscuting attorney poured whiskey on my head turned me around to face the jury and said 'Convict this man, he's drunk!" What could I do? I was framed! I never do nothin' wrong, but I always get the blame!" -- Little Feat
Aerolam
I am surprised no one has so far mentioned the Aerolam speakers manufactured by Celestion in the 1970's. Aerolam is an aluminium honeycomb composite originally designed for aircraft flooring. It is stiff and light and in the 70's Celestion used it in a number of speakers. The 2-way SL6 had a conventional damped chipboard carcass and Aerolam baffle. The subsequent SL600 was a fully Aerolam enclosure. Joining the the panels of the SL600 required then state of the art glues. Both models were small by standards of the day, bookshelf sized but were designed for stand mounting.The Interestingly, Celestion never produced a larger model with the same technology. I would guess that the stiffness gains are harder to realise in larger panels. I recall these speakers as having very limited SPL ability.
I recall a thread a while ago where someone proposed a loudspeaker with stiff panels based on stressed plywood skins over a simple central brace, similar to an aircraft wing cross section. He also argued that stiffness would solve the important problems. It failed spectacularly and he posted photos of the eventual bonfire event. I can't find the link however.
I am surprised no one has so far mentioned the Aerolam speakers manufactured by Celestion in the 1970's. Aerolam is an aluminium honeycomb composite originally designed for aircraft flooring. It is stiff and light and in the 70's Celestion used it in a number of speakers. The 2-way SL6 had a conventional damped chipboard carcass and Aerolam baffle. The subsequent SL600 was a fully Aerolam enclosure. Joining the the panels of the SL600 required then state of the art glues. Both models were small by standards of the day, bookshelf sized but were designed for stand mounting.The Interestingly, Celestion never produced a larger model with the same technology. I would guess that the stiffness gains are harder to realise in larger panels. I recall these speakers as having very limited SPL ability.
I recall a thread a while ago where someone proposed a loudspeaker with stiff panels based on stressed plywood skins over a simple central brace, similar to an aircraft wing cross section. He also argued that stiffness would solve the important problems. It failed spectacularly and he posted photos of the eventual bonfire event. I can't find the link however.
Ready-made (sturdy) box option
Another option perhaps not as dubious: Can your driver fit into a pre-sized (ready-made) box? Again using Riverside as an example, certain boxes are available in single quanitity and at "reasonable" prices. Example:
CT-36-CUBE,36x36x36" RSC corrugated carton,corrugated shipping box, Riverside Paper Co
A 36" cube for $22. 27 ft^3 is a big enclosure indeed. Cardboard tapped horn anyone?
Probably sturdier is the following option: cardboard shipping containers. Here is a likely example:
orrugated Shipping Crate, Triple wall shipping Crate, Crate Cube,CrateCube, rpconline.com
Available in several sizes, from ~$50-200, these might make an even better lazy man's enclosure. Had I known earlier, I would have bought one of these rather than the 12' of 12" flexible duct (~$250) which makes an easy (but not cost effective) quarter wave tube. But I digress. We are discussing "normal" boxes here...sort of. I calculate the per-square-foot material cost of a box is equal to roughly $61 per 4x8 sheet of plywood or MDF, so you can judge by that maybe.
Cons: other than the "it won't work based on physics" arguments people have made, perhaps validly, here are some cons:
1. You are limited to specified sizes.
2. You can't make the material more to your own spec (i.e. you could put a damping layer in DIY composite.)
3. The ready-made shipping crate is no cheaper (in materials, less labor) than a mid quality plywood or MDF build.
4. Cube shape is a "no-no" due to resonances (maybe not insurmountable -- more a problem with your room, not a box.).
Pros:
1. Great for the lazy or tool-less.
2. Might be worth a try if your speaker will fit in the volume of the box.
3. Perhaps, if you ever need to ship your speaker, no problem, because it is its own shipping container 🙂
Another option perhaps not as dubious: Can your driver fit into a pre-sized (ready-made) box? Again using Riverside as an example, certain boxes are available in single quanitity and at "reasonable" prices. Example:
CT-36-CUBE,36x36x36" RSC corrugated carton,corrugated shipping box, Riverside Paper Co
A 36" cube for $22. 27 ft^3 is a big enclosure indeed. Cardboard tapped horn anyone?
Probably sturdier is the following option: cardboard shipping containers. Here is a likely example:
orrugated Shipping Crate, Triple wall shipping Crate, Crate Cube,CrateCube, rpconline.com
Available in several sizes, from ~$50-200, these might make an even better lazy man's enclosure. Had I known earlier, I would have bought one of these rather than the 12' of 12" flexible duct (~$250) which makes an easy (but not cost effective) quarter wave tube. But I digress. We are discussing "normal" boxes here...sort of. I calculate the per-square-foot material cost of a box is equal to roughly $61 per 4x8 sheet of plywood or MDF, so you can judge by that maybe.
Cons: other than the "it won't work based on physics" arguments people have made, perhaps validly, here are some cons:
1. You are limited to specified sizes.
2. You can't make the material more to your own spec (i.e. you could put a damping layer in DIY composite.)
3. The ready-made shipping crate is no cheaper (in materials, less labor) than a mid quality plywood or MDF build.
4. Cube shape is a "no-no" due to resonances (maybe not insurmountable -- more a problem with your room, not a box.).
Pros:
1. Great for the lazy or tool-less.
2. Might be worth a try if your speaker will fit in the volume of the box.
3. Perhaps, if you ever need to ship your speaker, no problem, because it is its own shipping container 🙂
I hate it when you guys are right...
Was foolin' around in google patents. A search for "Loudspeaker enclosure" and "honeycomb" brings up ~50. One of the earlier is [one of] the Celestion ones. Interesting point it makes, and supports what an earlier poster here said: even a Aerolam (I assume) type enclosure will pass sounds (above? below?) a "critical frequency." The patent's solution is much damping internally.
Here is a quote from EP 0111408 A1 (patent app.): " Panels made from such sandwich material have an extremely high stiffness to mass ratio, and in theory are therefore well-suited for use as panels for a loudspeaker cabinet. However, it has previously been considered that sandwich-type material, although having a high stiffness to mass ratio, performs less well than chipboard panels when one considers the effect known as critical frequency. Above a particular frequency, known as the critical frequency, a panel becomes substantially transparent to sound, and at frequencies above this critical frequency the panels of the loudspeaker cabinet allow sound to escape through the panels. This can cause colouration of the sound for example."
Good for the would-be subwoofer: easier to damp high frequencies. For that matter, there should be few to no high frequencies originating in a subwoofer 🙂 Great! Now where did I lay that chicken wire and epoxy 🙄
Was foolin' around in google patents. A search for "Loudspeaker enclosure" and "honeycomb" brings up ~50. One of the earlier is [one of] the Celestion ones. Interesting point it makes, and supports what an earlier poster here said: even a Aerolam (I assume) type enclosure will pass sounds (above? below?) a "critical frequency." The patent's solution is much damping internally.
Here is a quote from EP 0111408 A1 (patent app.): " Panels made from such sandwich material have an extremely high stiffness to mass ratio, and in theory are therefore well-suited for use as panels for a loudspeaker cabinet. However, it has previously been considered that sandwich-type material, although having a high stiffness to mass ratio, performs less well than chipboard panels when one considers the effect known as critical frequency. Above a particular frequency, known as the critical frequency, a panel becomes substantially transparent to sound, and at frequencies above this critical frequency the panels of the loudspeaker cabinet allow sound to escape through the panels. This can cause colouration of the sound for example."
Good for the would-be subwoofer: easier to damp high frequencies. For that matter, there should be few to no high frequencies originating in a subwoofer 🙂 Great! Now where did I lay that chicken wire and epoxy 🙄
I don't see why the shipping boxes above wouldn't work. Don't like the shape, but that can be addressed in other ways. CLD on top of what is there should work quite well. Use of a hard surface (hardboard, masonite, BB etc) constrained but with free standing edges, internal and external
Have been thinking about using aluminum channel bonded directly to the inner wall from the outside, glued/flush riveted and that stiffing beam is also cl damped with a separate AL channel to the enclosure wall and then braced to the central dividers center line. For my purposes only require two lengthwise (4 dimensionally) per sub. These subs (mltl's) flank the MTM section which is an inner/outer box cld construction comprised of BB, masonite, and mdf, all CLD. For this to be most effective have selected various materials in 1/8", 3/16", 1/4", 3/8", 1/2" and 3/4" thicknesses.
Am considering making the center MTM section height adjustable as it sits between two oblong spheroid pillars.
Have been thinking about using aluminum channel bonded directly to the inner wall from the outside, glued/flush riveted and that stiffing beam is also cl damped with a separate AL channel to the enclosure wall and then braced to the central dividers center line. For my purposes only require two lengthwise (4 dimensionally) per sub. These subs (mltl's) flank the MTM section which is an inner/outer box cld construction comprised of BB, masonite, and mdf, all CLD. For this to be most effective have selected various materials in 1/8", 3/16", 1/4", 3/8", 1/2" and 3/4" thicknesses.
Am considering making the center MTM section height adjustable as it sits between two oblong spheroid pillars.
How about a Cornu-stye flat subwoofer?
Yet another idea (thank the deity of your choice I've yet to build this one):
Take a sheet of plywood (4x8, I may try a scrap of 4x4') and lay out a spiral horn that would have a single driver (I will model my 15" Alpine) in the center. Keeping with my recycled items and "composite" materials theme in this thread, will consider using the soda cans (two high = 10" approximately) for supports for a top piece and (this is the part I have yet to solve): they would be the pillars and the guides for the horn walls. Probably they are made of cardboard, maybe plastic. Whether these would be thick enough, I don't know. Based on my temporary "prototype", the soda cans are certainly strong enough: as shown in the earlier photo , I was able to stand atop a 2x2' square supported by maybe ten of my can-pairs and it held me (I weigh about 220 Lb.) So I think they could hold the top which might be just some stiff cardboard or thin plywood, anything that will let me mount the sub without it buzzing.
If I calculated correctly, a 4x4' sheet and 10" deep gives about 330 Litres of volume. If you wish, download my hornresp.dat file (below) and look at the last two simulations. If I've modelled it right, one is a back loaded tapered pipe usable maybe 18-67 Hz; the last is a proper horn for maybe 30-100 Hz.
Index of /shared/TEMP
If this idea is successful we can can start a new thread and it can breed on its own
Yet another idea (thank the deity of your choice I've yet to build this one):
Take a sheet of plywood (4x8, I may try a scrap of 4x4') and lay out a spiral horn that would have a single driver (I will model my 15" Alpine) in the center. Keeping with my recycled items and "composite" materials theme in this thread, will consider using the soda cans (two high = 10" approximately) for supports for a top piece and (this is the part I have yet to solve): they would be the pillars and the guides for the horn walls. Probably they are made of cardboard, maybe plastic. Whether these would be thick enough, I don't know. Based on my temporary "prototype", the soda cans are certainly strong enough: as shown in the earlier photo , I was able to stand atop a 2x2' square supported by maybe ten of my can-pairs and it held me (I weigh about 220 Lb.) So I think they could hold the top which might be just some stiff cardboard or thin plywood, anything that will let me mount the sub without it buzzing.
If I calculated correctly, a 4x4' sheet and 10" deep gives about 330 Litres of volume. If you wish, download my hornresp.dat file (below) and look at the last two simulations. If I've modelled it right, one is a back loaded tapered pipe usable maybe 18-67 Hz; the last is a proper horn for maybe 30-100 Hz.
Index of /shared/TEMP
If this idea is successful we can can start a new thread and it can breed on its own
I found a product similar to Greebster's in #25. I got "Soft Linking Mats" at Lowe's. I am experimenting with making a CLD (constrained layer). Many other builders do it by using (say) two sheets of birch and/or MDF between the viscoelastic layer. I've seen everything from Green Glue (Goo?), Titebond II, regular silicone, etc. promoted. I made a test join of the "Soft Linking mat" between a piece of plywood and a ceramic tile, using Gorilla Glue. Sticks fast. Also used is bitumen (asphalt roofing?) sheets or pads. I think these just add mass, for damping. BBC promoted the use of those in their speakers.
The above methods are well adapted to DIY because so far as I can tell, you can custom cut all the pieces as needed for size, openings, etc. I think it is important that each panel be not tightly joined to the next. I am unclear on how stuff is joined, in that case, maybe just the outer layer?
For testing purposes, I am wondering thus: for a CLD, must both panels be full sized, or could it be a mosaic of smaller pieces (say, smaller tiles or scrap wood?) I recently built a 24" cube sub using normal materials (so far): MDF and ply. I'm wondering if I can test a single panel of "composite" at a time to see how it works?
This stuff is all confusing: for a subwoofer the goal is to push the resonances up out of the low bass. For a normal woofer the goal is to push the resonances down below the passband. Somes times I regret giving up drinking
The above methods are well adapted to DIY because so far as I can tell, you can custom cut all the pieces as needed for size, openings, etc. I think it is important that each panel be not tightly joined to the next. I am unclear on how stuff is joined, in that case, maybe just the outer layer?
For testing purposes, I am wondering thus: for a CLD, must both panels be full sized, or could it be a mosaic of smaller pieces (say, smaller tiles or scrap wood?) I recently built a 24" cube sub using normal materials (so far): MDF and ply. I'm wondering if I can test a single panel of "composite" at a time to see how it works?
This stuff is all confusing: for a subwoofer the goal is to push the resonances up out of the low bass. For a normal woofer the goal is to push the resonances down below the passband. Somes times I regret giving up drinking
Last edited:
My skull is a resonant cavity 
With a sealed box, ideally the backwave is completely absorbed. In the real world, it is energy (mechanical, air movement) that exerts force on the box. The energy can't be stored (other than short-term), it must either escape the box as new vibration, possibly at a different frquency, or be converted into heat energy by baffles or flexing. I've never heard of a loudspeaker catching on fire (from friction anyway!) If this be the case, some sound (vibration) must be radiated? With a subwoofer, the usual goal is a stiffer box, with more bracing. = higher resonances. But the opposite with mid-woofer enclosure. Why could not a sub's frequency be lowered too? Possibly, it would not be as coloring a distortion as would be a higher frequency.
With a sealed box, ideally the backwave is completely absorbed. In the real world, it is energy (mechanical, air movement) that exerts force on the box. The energy can't be stored (other than short-term), it must either escape the box as new vibration, possibly at a different frquency, or be converted into heat energy by baffles or flexing. I've never heard of a loudspeaker catching on fire (from friction anyway!) If this be the case, some sound (vibration) must be radiated? With a subwoofer, the usual goal is a stiffer box, with more bracing. = higher resonances. But the opposite with mid-woofer enclosure. Why could not a sub's frequency be lowered too? Possibly, it would not be as coloring a distortion as would be a higher frequency.
Attachments
Last edited:
If you take a woofer out of its designed sealed box and put it in a hole through the wall of your house, the backwave is absorbed by the outside world, 100%. Does anything else change?
That is cheating...
Of course that is the best way to deal with the rear wave. However, you basically have turned your room into the speaker box 🙂
It would be a great soution if you could decide where to place the drivers and never expect to move them again.
Of course that is the best way to deal with the rear wave. However, you basically have turned your room into the speaker box 🙂
It would be a great soution if you could decide where to place the drivers and never expect to move them again.
Based on the (relative) success of my current "normal" subwoofer (a 24" cube made of MDF and ply), I am itching to try a simpler (?) "alternative" construction, probably about the same dimensions. I've already toyed with it, and it has merit: use aluminum cans one or more high, glued together for strength. If you Google "aluminum can construction", all kinds of project have been done, from hobby and craft to actual buildings ("non-load-bearing" seems to be a recurrent phrase, however). On the upside, I have no fear of a collapsing subwoofer injuring anyone nor running afoul of the building code. First experiment will be to make a panel, 24x24", probably just cardboard facings, and a single layer of cans. It would be nice to put a "constrained layer" there...is there a cheap glue or similar that can pour into the voids? Especially something that would remain elastic. I see no need to fill the cans but one could...I just want to try the lightweight approach first.
Although my liver and my higher power no longer wish this, for many hobbyists it would be a fun excuse to indulge in one's favorite beverage to accululate a supply of building material. While my project is not as classy as building ships in a bottle, you gotta get the bottle (or can) from somewhere
Although my liver and my higher power no longer wish this, for many hobbyists it would be a fun excuse to indulge in one's favorite beverage to accululate a supply of building material. While my project is not as classy as building ships in a bottle, you gotta get the bottle (or can) from somewhere
A nice source of honeycomb material. I have handled these products and they are finely made. I have rocked back and forth on a curved section and can testify to their rigidity.
Pricey but pretty. Could you make a good speaker out of this shaped tube?
😀
Pricey but pretty. Could you make a good speaker out of this shaped tube?
😀
- Status
- Not open for further replies.