Well this is an idea I heard when I was working for a local speaker builder which I want to implement in my current project and wanted to know if anyone has done this and what the results were. The method is basically having say a typical speaker cabinet made of plywood, drilling a hole in two opposite panels (at the same location) and running something like aircraft cable or even a long bolt through it. Then if using a bolt, simply tighten while listening to music until you feel it sounds good. Of course you'd have to be careful not to over tighten and crack/collapse the cabinet.
Now this got me thinking. And this is a bit of a nutso idea and a lot on here will not like it. What if you were to use a series of strings (say bass guitar strings) and actually tighten and tune them to certain notes, or all 7 whole notes. The issue would be that not all music is played on instruments tuned to A440 but I'm wondering if the right combination of stiffness and damping were used, along with the tuned strings, would this blur the music or would the specific resonances enhance the experience..? Maybe for stringed instruments it would work, but what about wind, brass, synths etc.. ?
I will probably try this sometime for the hell of it. But for the current project I'm staying on planet earth and using half inch bolts and tightening a half inch baltic birch floorstander in two locations. The bolts will be covered in some sort of goop to help deaden any ringing that may occur (maybe I will brace the bolts themselves) and some sort of sealant will be used at the ends to seal air gaps. There will also be a typical wood brace that is not too close and not too far away from the tension points to prevent the walls from flexing in too much in the center (for visual reasons) and to help stiffen the walls further by having an extra tension point. Any thoughts?
Now this got me thinking. And this is a bit of a nutso idea and a lot on here will not like it. What if you were to use a series of strings (say bass guitar strings) and actually tighten and tune them to certain notes, or all 7 whole notes. The issue would be that not all music is played on instruments tuned to A440 but I'm wondering if the right combination of stiffness and damping were used, along with the tuned strings, would this blur the music or would the specific resonances enhance the experience..? Maybe for stringed instruments it would work, but what about wind, brass, synths etc.. ?
I will probably try this sometime for the hell of it. But for the current project I'm staying on planet earth and using half inch bolts and tightening a half inch baltic birch floorstander in two locations. The bolts will be covered in some sort of goop to help deaden any ringing that may occur (maybe I will brace the bolts themselves) and some sort of sealant will be used at the ends to seal air gaps. There will also be a typical wood brace that is not too close and not too far away from the tension points to prevent the walls from flexing in too much in the center (for visual reasons) and to help stiffen the walls further by having an extra tension point. Any thoughts?
Well I kinda like the idea about inward tension but not so much the idea of the guitar strings. The way I am thinking about it you can either damp them or let them resonate - no in between or you will just cause buzzing. Also over time I would expect the strings will stretch out and become "dead". At least if you are going for a hi-fi speaker or one meant for program material I would ditch the idea of the resonance but keep the idea of being able to adjust the tension.
Now for a colored instrument speaker that utilizes resonance the idea might be worth experimenting a little with. Of course musicians have enough doo dads to tinker with and have to tune already and I tend to stick with things that just sound good with minimal need for tweaking in terms of what I use on instruments. And I don't think I tune to strict A 440 haha.
Anyway I would still try it regardless of anything said in this thread I am stubborn like that with ideas.
Now for a colored instrument speaker that utilizes resonance the idea might be worth experimenting a little with. Of course musicians have enough doo dads to tinker with and have to tune already and I tend to stick with things that just sound good with minimal need for tweaking in terms of what I use on instruments. And I don't think I tune to strict A 440 haha.
Anyway I would still try it regardless of anything said in this thread I am stubborn like that with ideas.
Nice signature, John.
I wonder if those cross bolts for the Pioneer stage gear was to help the sound or to help them from falling apart!
I'm not sure the strings would keep stretching out. After a certain point they either stop stretching or break. And since nobody would be physically plucking at them I don't think they'd break. I always thought they became dead due to the acid and gunk that comes out of my pores! And humidity and temperature play a role in de-tuning over time as well. And I bet the actual guitar is just as much the culprit here as the string if not more. But I'll stop assuming.
The thing is that the more you tighten the string the more inward tension and the less uncontrollable vibration of the walls. So with a very stiff material to begin with the actual resonance would probably be on a small scale but maybe just enough to add some sweetness. I am putting on the fire retardant suit now.
I wonder if those cross bolts for the Pioneer stage gear was to help the sound or to help them from falling apart!
I'm not sure the strings would keep stretching out. After a certain point they either stop stretching or break. And since nobody would be physically plucking at them I don't think they'd break. I always thought they became dead due to the acid and gunk that comes out of my pores! And humidity and temperature play a role in de-tuning over time as well. And I bet the actual guitar is just as much the culprit here as the string if not more. But I'll stop assuming.
The thing is that the more you tighten the string the more inward tension and the less uncontrollable vibration of the walls. So with a very stiff material to begin with the actual resonance would probably be on a small scale but maybe just enough to add some sweetness. I am putting on the fire retardant suit now.
A lot of car audio SPL competitors do the same thing. Lots of pressure in those enclosures.
Well yeah there would more things that would contribute to strings breaking on a real guitar which is being used. But strings do lose there elasticity over time - it might just take more time in your case. I find this is the number 1 cause of broken strings with guitarists - either too much elasticity because they didn't stretch the strings as they added tension and strung the guitar (which can lead to slippage) or a lack of elasticity from age and wear.
And also thinking about it they might not be as adjustable as you would need for this application since they will break if they are tuned higher than concert pitch.
My problem with the idea of resonance is you can't control it. It can only add inaccuracy and get in the way of realism (says the hypocrite who loves his Bass Reflex speakers)
And also thinking about it they might not be as adjustable as you would need for this application since they will break if they are tuned higher than concert pitch.
My problem with the idea of resonance is you can't control it. It can only add inaccuracy and get in the way of realism (says the hypocrite who loves his Bass Reflex speakers)
I guess it depends on how the box is constructed and how much tension is applied. I think i know what you are saying though. If a box is made with 45 degree edges then inward stress is the right kind. And the glue joints would break with outward force before they did if inward force was applied.
But you are right that it's the same thing whichever way the pressure is applied I just think this method is probably the easiest and most practical way of tightening the walls to the brink.
But you are right that it's the same thing whichever way the pressure is applied I just think this method is probably the easiest and most practical way of tightening the walls to the brink.
Wasn't it Triangle that had the philosophy (if you can call it a philosophy) of building their speakers to resonate (after a fashion) like musical instruments? I remember hearing some of their stuff maybe ten years ago and liking them quite a bit.
If I wanted to play with tension I think I'd try something like one of these maybe even going so far as make the faces slightly convex by making them out of smaller triangles with the vertex at the centre of the face so that applying tension from vertex through the interior of the enclosure to opposing vertex makes the face itself more rigid. . . . The trouble is, with forms like these all the internal cables will want to pass through exact centre so they'll all try to displace each other unless you build an internal hub. Oh, and all the face edges will want to be beveled at the proper angle so they won't pull by each other when you're tightening them up
. . . . .
Gee, it's starting to sound like quite a project . . . . . better get started!
If I wanted to play with tension I think I'd try something like one of these maybe even going so far as make the faces slightly convex by making them out of smaller triangles with the vertex at the centre of the face so that applying tension from vertex through the interior of the enclosure to opposing vertex makes the face itself more rigid. . . . The trouble is, with forms like these all the internal cables will want to pass through exact centre so they'll all try to displace each other unless you build an internal hub. Oh, and all the face edges will want to be beveled at the proper angle so they won't pull by each other when you're tightening them up
. . . . .
Gee, it's starting to sound like quite a project . . . . . better get started!
using bolts to tension speaker
You might want to consider using all-thread (threaded rod) and putting nuts and washers on the all thread, to sandwich the panels between nuts. Maybe a gasket material also to decouple the washers from the wood.
To me this sounds like an adjustable version of a wooden dowel, with potential advantages.
Good luck.
You might want to consider using all-thread (threaded rod) and putting nuts and washers on the all thread, to sandwich the panels between nuts. Maybe a gasket material also to decouple the washers from the wood.
To me this sounds like an adjustable version of a wooden dowel, with potential advantages.
Good luck.
Yeah that's basically what i'm doing except the bolt is not all threaded. Just at the end. But it will work the same way. Funny thing is a couple of days after i opened this thread I went to a friends house who used to be in the speaker business and he had bought back a pair of his old speakers which had exactly what we're describing here! What are the chances.
Somebody mentioned putting nuts on both sides of the walls. That should work quite well and would be a boon for people who don't have the equipment to install bracing easily (dado, etc.)
If you wanted to install them on enclosures that are already glued up, you could cut the threaded rod into two sections each and use clamp-on threaded shaft collars once the rod goes inside.
If you wanted to install them on enclosures that are already glued up, you could cut the threaded rod into two sections each and use clamp-on threaded shaft collars once the rod goes inside.
That's who my friend made them for. Actually he had a guy in town build them (who i worked with at a different time) for him and then sold them to Michael Green. The pair with the bolts at his place have a Cambridge Audio woofer, which was news to me(sounds great though), and what looks to be a Vifa tweeter. Nice little elegant floor standers.
I can tell you first hand. I've got a bass guitar. If you want decent sound most bass players will tell you you have to mute the strings you are not playing. Bass playing is as much about muting strings as striking them. So you idea could work but you's need to mute the strings. Maybe just pack the cabinet with that white "fluff".
It turns out that strings don't just resonate with their own note. The E string will pick up harmonics from a C and many other combinations all going on at once. Sounds like mud. you really do have to keep a finger on the un-played strings. You want the cabinet to be acoustically dead
You do NOT ever want to but anything in a hifi speaker cabinet that even comes close to resonating. Guitar cabs are different. I just built one using 3/4 inch pine. It adds to the tone and sounds good. (Just to see what would happen I tried playing some solo piano music through this guitar cab. It was quite poor, really bad)
Point contact isn't going to do much to brace the panel. You want line contacts to divide the panel into smaller ones (the aim of bracing). The smaller panels resonate at higher frequencies and these are easier to damp.
I Once saw a test where they used single dowels (glued, IIRC) and the first resonance of the panel was nearly unchanged. IIRC, a brace at right angles to the sides/top did better than a diagonal one, perhaps a counter-intuitive result.
I believe the best arrangement is a brace along the longest dimension of the panel, just off center. IMO, shelf braces and ribs are the most practical/effective thing to do. I try not to have more than 4-6" of unbraced panel.
I Once saw a test where they used single dowels (glued, IIRC) and the first resonance of the panel was nearly unchanged. IIRC, a brace at right angles to the sides/top did better than a diagonal one, perhaps a counter-intuitive result.
I believe the best arrangement is a brace along the longest dimension of the panel, just off center. IMO, shelf braces and ribs are the most practical/effective thing to do. I try not to have more than 4-6" of unbraced panel.
I did this very thing 16 some odd years ago, with my 3x10" driver, 4x4" ported sub box back in my mobile audio days. Everything came through the front panel and was far too busy to effectively use traditional bracing...., (with any ease that is).
Worked like a charm to stiffen up the front baffle, and wouldn't think twice if the occassion called for it.
I did it too , but 14 years ago , as for plastic in the bottom and on top , reinforced with wood , it was the only way.
http://www.diyaudio.com/forums/attachment.php?attachmentid=136522&d=1246432242
http://www.diyaudio.com/forums/attachment.php?attachmentid=136522&d=1246432242
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