Not practical to ship thou.
Lovely car. We used to sneak into the drive in theatre in the trunk of something like that.
dave
I remember there was a post some time by a guy who made concrete speakers with chips of those floating foam things you get dor the pool (looks like a stick)
Aluminium
And that is why I opted for Paradigm Signature 1's rather than 2's. I wanted a metal enclosure and was just not up to casting my own. Sorry DIY'ers.Regards, John Dozier
And that is why I opted for Paradigm Signature 1's rather than 2's. I wanted a metal enclosure and was just not up to casting my own. Sorry DIY'ers.Regards, John Dozier
Wavebourn, maybe!
Al is a very stiff material, it isn't prohitivly excpensive, and relativly easy to work with. If you can get Al at scrap prices your maine worrie is cost and availabilty of cutting shops for cutting Al sheet. A sample of a price of sheet Al at scarp yard prices:
Aluminium Sheet/Plate6082Offcut 470mm x 80 x 20mm CN27 - eBay (item 160538136839 end time May-27-11 04:34:58 PDT)
unless you can get the Al as scrap, you need to purchase 1.5 by 2 meter sheet, at retail price, not cheap.
Then there's damping. Unless damped it rings like a bell of course, it needs to be treated. damping with lead is particularly easy and effective, since you are able to pour hot lead to cover inner walls, one by one. By amount of lead poured u are able to predict the thickess and how much is needed to 'silence' the resonnaces. Pouring lead on the inner walls also gives perfect contact with Al enclosure, u end up with one solid wall made up with 2 dif materials.
Of course it could never be done as a commercial product. It is lead after all and supposedly kills instantly, lol. Manufacturing and shipping costs would be such that retail price of, say size of Dynaudio Contour 1.3 would be un marketable. But then again, when Wilson Audio came up with 2way monitor using Scanspeak 6 inch woofer and Focal Ti tweeter, the Watt, it cost $4500 in 1985. It was unheard of amount for a 'bookshelf'. digits would have laughed at the Watts so hard and made clever remarks what an overkill it is. Wilson ended up selling tons of them.
link to Watt enclosure and their use of lead as damping material, please go to paragraph starting with: "The enclosure material for the WATT.."
http://www.stereophile.com/floorloudspeakers/607wilson
Al is a very stiff material, it isn't prohitivly excpensive, and relativly easy to work with. If you can get Al at scrap prices your maine worrie is cost and availabilty of cutting shops for cutting Al sheet. A sample of a price of sheet Al at scarp yard prices:
Aluminium Sheet/Plate6082Offcut 470mm x 80 x 20mm CN27 - eBay (item 160538136839 end time May-27-11 04:34:58 PDT)
unless you can get the Al as scrap, you need to purchase 1.5 by 2 meter sheet, at retail price, not cheap.
Then there's damping. Unless damped it rings like a bell of course, it needs to be treated. damping with lead is particularly easy and effective, since you are able to pour hot lead to cover inner walls, one by one. By amount of lead poured u are able to predict the thickess and how much is needed to 'silence' the resonnaces. Pouring lead on the inner walls also gives perfect contact with Al enclosure, u end up with one solid wall made up with 2 dif materials.
Of course it could never be done as a commercial product. It is lead after all and supposedly kills instantly, lol. Manufacturing and shipping costs would be such that retail price of, say size of Dynaudio Contour 1.3 would be un marketable. But then again, when Wilson Audio came up with 2way monitor using Scanspeak 6 inch woofer and Focal Ti tweeter, the Watt, it cost $4500 in 1985. It was unheard of amount for a 'bookshelf'. digits would have laughed at the Watts so hard and made clever remarks what an overkill it is. Wilson ended up selling tons of them.
link to Watt enclosure and their use of lead as damping material, please go to paragraph starting with: "The enclosure material for the WATT.."
http://www.stereophile.com/floorloudspeakers/607wilson
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Having a cast aluminum enclosure doesn't automatically ensure a fantastic speaker. Most of the full range Fostex (and others) desktop size speakers I've tried easily beat the cast aluminum Canton HC100's. Granted, all these speakers are bass challenged.😉
jeff
We want to change the panel material, at least the combination of the panel layers. Damping adds mass and may slightly shift resonant modes downward but not to any extent that makes it hard to track what is going on. I haven't seen reasonable amounts of damping change cabinet performance other than to reduce the Q (peak height) of the resonances. Isn't that what we want?
I'd still like an explanation of what this means.
It means what i've said. I've expressed it in a number of ways, and you'll just have to meditate on what has been said until such time (or not) as you can overcome the inertia of your current beliefs and make a leap to understanding.
You already understand how it works in a subwoofer.
dave
Al is so often used for just the 'techno' look, the thickness of sheet metal used in most hi end designs is very thin. Burmester uses it purely for cosmetics to match the appearnce of their 10 000 Euro amplifiers, their top end speakers look like amps. So do many others, like Elac, aslo German manufacturer.
Krell had a 'serious' speaker with enclosure made partly of Aluminum, $37,500/pair, please read the review, some interesting thoughts about all out cabinet design in that article.. sorry for another Stereophile link, but Larry Greenhill reviews were always informative
Krell LAT-1 loudspeaker | Stereophile.com
haa, there is really funny line in that review: 'The LAT-1 gets its solidity, density, and inertness from aluminum'
aluminum alone as enclosure material is very far from inert, actually opposite is true. still good read tho..
Krell had a 'serious' speaker with enclosure made partly of Aluminum, $37,500/pair, please read the review, some interesting thoughts about all out cabinet design in that article.. sorry for another Stereophile link, but Larry Greenhill reviews were always informative
Krell LAT-1 loudspeaker | Stereophile.com
haa, there is really funny line in that review: 'The LAT-1 gets its solidity, density, and inertness from aluminum'
aluminum alone as enclosure material is very far from inert, actually opposite is true. still good read tho..
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If you are refering to your 1 over the 2nd power or 1 over 4th power curves, I'm not buying the validity or relevance of them. Most cabinet curves I've seen, including the Harwood and the German site show relatively flat energy in the resonances up to about 2 kHz. Nothing is nose diving at 300 Hz. If panel output is fairly flat from a log frequency sweep then how is energy falling?
Are you pushing your panel resonances all above 2kHz? Is that what you are saying? That would be the counterpart to the subwoofer solution applied to a typical 2 way. I would love to see accelerometer curves of a cabinet with its fundamanetal wall resonances pushed above 2kHz. As you know when you make the walls of a cabinet thicker and more massive the stiffness tends to go up as well. One fights the other in terms of raising wall resonances. It takes a lot of work (material cost) to raise typical cabinet resonances by an octave, let alone 3.
I assume you aren't refering to placing resonances between the notes of an equall tempered scale, although you mentioned that in a previous thread. I've already explained the unlikeliness of that (but would still like to see accelerometer curves to prove me wrong).
David S.
Aluminium
Mr. Bagby and company at Paradigm carefully thought out their use of this material with heavy internal bracing and dampening. I am not a neophyte at this having owned thru the years, the original Acoustat with tube amps, Apogee ribbons, and AE1's (the original) I also have a substantial background in professional classical recording and use my own commercial cds for reference. A small aluminium enclosure, suitably dampened, I still think provides the least box talk of any commercially viable construction. I have to say that the AE's with a combination of massive wood construction and assymetrically poured plaster came in a close second.
Mr. Bagby and company at Paradigm carefully thought out their use of this material with heavy internal bracing and dampening. I am not a neophyte at this having owned thru the years, the original Acoustat with tube amps, Apogee ribbons, and AE1's (the original) I also have a substantial background in professional classical recording and use my own commercial cds for reference. A small aluminium enclosure, suitably dampened, I still think provides the least box talk of any commercially viable construction. I have to say that the AE's with a combination of massive wood construction and assymetrically poured plaster came in a close second.
When i again find the text book reference that i searched for to back up Svante's original post on the subject you may well have to rethink that. It sure works in practise. And many an allusion to it in Atkinson's measures.
I would too. Just need to get all the rest of the pieces in place.
BTW. A 2-way around here usually has the XO <400 Hz. Most are 1-way.
I am not. To do that would would have to hand tune each cabinet. Maybe OK for a one-off, but the boxes i design are made by many.
dave
Dave1 and Dave2 quick bickering...MODS SHOULD SET AN EXAMPLE.
P10: you know your stuff. You a math wizz. Well done. But dont preach, til you CAN cite proof. Theory NEVER matches reality 100%. I would personally LOVE to see accelerometer analyses, forget curves, how about FFTs?
Speaker dave: You also know alot.
both of you should maybe work TOGETHER? not argue. debate is debate, but this is bordering on the nutty.
ME: Im OK at maths. I have far less experience than either of you. I work with vibration kit often though. And my weak theory may make you sceptical, but additional bracing can actually make a situation WORSE. I work to IEC standards for rotating machines. 3600rpm match has a basic res of 60hz. chassis of 60mm plate. severe vib probs. plate braced and strengthened with additional 60mm square stock. acc leveks at F1 jumped from 12mm/s RMS to 50mm/s RMS, disp off the scale. in overbracing, ONE can coalesce multiple panel resonances into ONE much greater one.
This is why damping is used in as many situations as reinforcement bracing.
There is NO SINGLE correct way. you are both as right as you are wrong.
BUT. as a living i analyse and record vibration, acc, vels and disp all day long. I could perform a full spectral FFt analyses NOW if i had my speakers here at work with me. I could 'bonk test' your cabs in about 5 mins. And a brass piezo sounder isnt gonna cut it. Cant calibrate it, not worth trying to salvage results with it. Get some Oros kit, or ADRE, if you got about 60k in your back pocket. Oh and a calibrated hammer. 😎
P10: you know your stuff. You a math wizz. Well done. But dont preach, til you CAN cite proof. Theory NEVER matches reality 100%. I would personally LOVE to see accelerometer analyses, forget curves, how about FFTs?
Speaker dave: You also know alot.
both of you should maybe work TOGETHER? not argue. debate is debate, but this is bordering on the nutty.
ME: Im OK at maths. I have far less experience than either of you. I work with vibration kit often though. And my weak theory may make you sceptical, but additional bracing can actually make a situation WORSE. I work to IEC standards for rotating machines. 3600rpm match has a basic res of 60hz. chassis of 60mm plate. severe vib probs. plate braced and strengthened with additional 60mm square stock. acc leveks at F1 jumped from 12mm/s RMS to 50mm/s RMS, disp off the scale. in overbracing, ONE can coalesce multiple panel resonances into ONE much greater one.
This is why damping is used in as many situations as reinforcement bracing.
There is NO SINGLE correct way. you are both as right as you are wrong.
BUT. as a living i analyse and record vibration, acc, vels and disp all day long. I could perform a full spectral FFt analyses NOW if i had my speakers here at work with me. I could 'bonk test' your cabs in about 5 mins. And a brass piezo sounder isnt gonna cut it. Cant calibrate it, not worth trying to salvage results with it. Get some Oros kit, or ADRE, if you got about 60k in your back pocket. Oh and a calibrated hammer. 😎
I read somewhere that Addison was considered crazy because instead of pleasant conversations with people he used to go around, knock everything, listening to response... 😉
I'll get there. More for my own education than anyone elses. I have an accelerometer, no preamp for it yet (i leave the electronics to the boy genius).
What i would really like to see is a spectrograph from the accelerometer of the panel for a whole song, over a range of songs.
For now a mechanics stethescope gives pretty good feedback (uncalibrated and not shareable). And the relaxed smile on my (and others) faces when i sit down to listen.
I'll shut up now.
dave
readings for a whole song would be great. but im unsure what you would glean from it. Its no criticism , but myself, perhaps in my own ignorance or naivity(SP) believe transient sine tonebursts, or filtered noise would be more useful. Although damned boring 😀.
Again though, I could be entirely wrong in that assumption.
p.s. in my employ a mechanics stethoscope consists of a large phillips screwdriver...
Again though, I could be entirely wrong in that assumption.
p.s. in my employ a mechanics stethoscope consists of a large phillips screwdriver...
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