It is interesting to see where you guys are at when it comes to loudspeaker cabinets.
Of course, I went through a speaker building phase, 40 years ago and more. In 1970, I found that the Grateful Dead dual 15"D130 speaker cabinets made of 15 ply Finnish birch were exceptional at their time. However, within a few years I met some people at the London AES in 1975, who clued me in about speaker cabinet Q, and how hard it is to reduce the resonances. I tried, at the time using thick wood, sandwiched with some very damped insulation material in order to lower the inherent Q. It did OK, and for the next 10 years, lived with KHorns, Magnepans, BC-3-5A's with a subwoofer, and finally Dave Wilson gave me a set of the WATT-Puppy 1's, and I fell in love with the 'lack of sound' of the speaker cabinets. Dave is really on to something, when it comes to cabinet construction. Once you listen to his effort, it is hard to go back to traditional cabinets made of traditional wood and bracing, and that is where most here seem to be at. It would be useful to read some papers by Barlow, etc about the problem.
Of course, I went through a speaker building phase, 40 years ago and more. In 1970, I found that the Grateful Dead dual 15"D130 speaker cabinets made of 15 ply Finnish birch were exceptional at their time. However, within a few years I met some people at the London AES in 1975, who clued me in about speaker cabinet Q, and how hard it is to reduce the resonances. I tried, at the time using thick wood, sandwiched with some very damped insulation material in order to lower the inherent Q. It did OK, and for the next 10 years, lived with KHorns, Magnepans, BC-3-5A's with a subwoofer, and finally Dave Wilson gave me a set of the WATT-Puppy 1's, and I fell in love with the 'lack of sound' of the speaker cabinets. Dave is really on to something, when it comes to cabinet construction. Once you listen to his effort, it is hard to go back to traditional cabinets made of traditional wood and bracing, and that is where most here seem to be at. It would be useful to read some papers by Barlow, etc about the problem.
Yes, evidently Audio Note thinks the panels should vibrate, and has some adherents (not me!).
It seems somewhat comparable to Hiraga's notions of the distortion spectrum of an amplifier having a particular falloff with the harmonic number as being beneficial. Keith Howard's writing again here, suggesting that cleaner was always better to his ears.
Brad
Overkill. DIY CLD is much easier on the back come moving time.
Extreme, in the other direction, but works well with CLD: There are guys on the multiway forum making speaker boxes out of the foam panels you can buy in craft shops.
http://www.diyaudio.com/forums/full-range/223313-foam-core-board-speaker-enclosures.html
They're having fun and can build exotic enclosures fast and super cheap.
I used the woofer connected to a signal generator as the vibrator during the initial filling. Then during use, music was a mild vibration generator. Every week or so for some months, a few mallet blows helped complete toping up without any voids.
I had build a sealed subwoofer box this way, the same dimentions with one I had built before which was laid internally with 2mm lead sheet, epoxied to 22mm MDF.
The sand filled box was more vibration free than the leaded box.
Scott
You can’t easily damp vibrations of a panel with a high uniform mass.
Thin braced (and most important, acoustically small) panels with unevenly distributed mass and selective damping is a much better choice.
George
The MDF here is 56lb for that size, it must vary (4'X8'X.75 = 96lB). You would appreciate my local supplier, they source goods for the east coat yacht industry but will sell tiny quantities to the public at nice prices. They have a scrap bin full of crazy stuff like teak and okoume multiply in the style of baltic birch.
When Harman was getting its computer speaker business off the ground, despite being responsible just for electronics, I poked my nose into the cabinet bracing a bit and suggested a sort of Penrose tiling of the interior of the plastic boxes. As he didn't think of this himself my boss was customarily dismissive of the idea. The shame was we had a full-time FEA guy on the staff who could have modeled it and determined the characteristic resonances.
A much later loudspeaker pair, initially having some industrial design spin connected with putative ETs and named accordingly (Roswell was one, Area 51 another, Creature a third), but later renamed the neutral "Duet", had, for a change, a felicitous shape for both cabinet rigidity and decent off-axis behavior. I listen to them at desktop still quite happily, and wish that they had an EQ-changing subwoofer line level output---a feature that studies showed had an almost zero attachement rate, so it was elminated
A much later loudspeaker pair, initially having some industrial design spin connected with putative ETs and named accordingly (Roswell was one, Area 51 another, Creature a third), but later renamed the neutral "Duet", had, for a change, a felicitous shape for both cabinet rigidity and decent off-axis behavior. I listen to them at desktop still quite happily, and wish that they had an EQ-changing subwoofer line level output---a feature that studies showed had an almost zero attachement rate, so it was elminated
As i'm more a scientist than a groupie, i use a very sophisticated protocol of measurement to figure out the quality of a cabinet. Nothing to read, just knocking everywhere on the box with my finger. When you hear the same sound you have when you knock the pillar of a bridge made of concrete, and have hurt your finger, you're done.
I am sure you're right: the weight of my lead is more annoying that the damping it provides. Not to talk about the risk for the heath if you do not cover each and every millimeter of it with some air-proof coating.
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But very popular - a proper DIY enthusiasts mag, continuing the tradition of Electronics Australia.That "Majestic" from 2014 looks right up your alley, in fact are you a ghost writer for Silicon Chip?
June 2014 - Silicon Chip Online
Regarding enclosures, the DEQX bloke up the road did sealed subwoofers with double skin, filled with dry sand - good news! Subwoofers that don't sound like such - a bass note is only there when it's supposed to be, nothing obnoxious in that area ....
Dave has a complete acoustical lab with 100's of thousands of dollars in measuring equipment. Tapping with your finger is OK, but there is more to it.
I must admit, that if I had to pay full retail for Dave's speakers, they would always have been beyond my budget. I have heard other speakers that I like as well, but Dave's cabinets are exceptional. It has nothing to do with being a 'groupie' and I resent your implication, but a professional relationship where I have attended loudspeaker listening sessions with him, designed advanced analog electronics for him (I got paid for my efforts) along with making his mike preamps, and for some years, his phono and line reproduce systems. IF and when Dave found something better than my efforts, he would change to it. This happened several times, over the decades.
You might think of Dave's contribution of his loudspeakers to me as a token or bonus of gratitude that he has for giving him advanced electronics for the last 33 years or more.
I must admit, that if I had to pay full retail for Dave's speakers, they would always have been beyond my budget. I have heard other speakers that I like as well, but Dave's cabinets are exceptional. It has nothing to do with being a 'groupie' and I resent your implication, but a professional relationship where I have attended loudspeaker listening sessions with him, designed advanced analog electronics for him (I got paid for my efforts) along with making his mike preamps, and for some years, his phono and line reproduce systems. IF and when Dave found something better than my efforts, he would change to it. This happened several times, over the decades.
You might think of Dave's contribution of his loudspeakers to me as a token or bonus of gratitude that he has for giving him advanced electronics for the last 33 years or more.
Aussie speakers are generally far better built than the overseas stuff - you would go into a hifi shop, and tap the side of a Brit box - it would ring for about 5 minutes, - the Oz box next to it would only yield a dull thud, .
Quite a few months ago I got quite serious about developing a speaker paneling product, that involved multiple thin layers with carefully organised shaping of the connection elements, and very high levels of damping filler. Would have been relatively light, but vastly superior to straight MDF, etc, with regards to resonance, extremely dead acoustically. Got put to one side when something else turned up, haven't gone back to it ...
- the Oz box next to it would only yield a dull thud, .Quite a few months ago I got quite serious about developing a speaker paneling product, that involved multiple thin layers with carefully organised shaping of the connection elements, and very high levels of damping filler. Would have been relatively light, but vastly superior to straight MDF, etc, with regards to resonance, extremely dead acoustically. Got put to one side when something else turned up, haven't gone back to it ...
It was only a very average Brit box, B&W, that gave me the first dose of worthwhile sound - but the key reason it did that was that I put a huge amount of effort into stabilising it. It wasn't bouncing around like the typical farty little bookshelf, but locked solidly to the floor - it effectively become an extension of the house foundation mass. This especially gave it extremely authorative bass - guts, without the normal blubber ... conventional setting up of speakers often yields very "tiny" sound, only slightly better than the kitchen radio type of thing ...
Details?, you're at it again. This is a DIY forum where we ostensibly share things we do to get better whatever.
Typo, my concentration sucks today, should have been 80 instead.
High density fibreboard doesn't float in water, specific weight is right in the middle of MDF and HPL phenolic resin board.
(some guy in Croatia decided to have the entire interior of his 83ft yacht replaced by white HPL panelling, and sleep in his bathroom. Currently for sale at less than 1/4th of the original asking price. Cheap refit, bad judgement)
The HK GLA-55 loudspeaker design is out of this world.
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I see it is in a substantially restyled version now. One of the sad things about them is the "grill" messes with the response. When the tech measured them the satellites looked beautiful. Unfortunately he probably mixed up files, and what I had to work with for EQ later was far less promising. I tried to get the three-pronged thing to be made out of mostly a screen material, to no avail. However, everybody including the iLounge guy seemed to love them, and it would get plugged as a comparison when he'd review some roughly comparable three-piece system.
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Tsk, I've already done this a couple of times in posts on other threads - it would be a tiresome vomiting it out every time, both for me and other readers - the key point I'm making is that stabilising is important , however one chooses to do it ...
But, to keep you happy, I will repeat ... !!
Concrete pillars, garden shop type of blocks glued together with appropriate adhesive, all cavities filled with sand; concrete slab top and bottom - a solid unit, can be picked up and carried as an item. Decent quality, long spikes in a triangle configuration - no rocking please! - under bottom slab forced to punch through the carpet and underlay, 100% mated to the concrete foundation below. Speaker carcase locked to the top slab at the corners with Blu Tack, heavily compressed. Top of the speaker very heavily mass loaded with - wait for it! - multiple volumes of coffee table sized books, to a far old height. Yes, looked absolutely ridiculous - but the resulting sound is all that mattered.
What I was after is that light pushing on the side of the speaker - did nothing! Felt like pushing on the side of a bank safe - by comparison, going to a hifi shop and pushing in the same way on the side of a Wilson type monolith parked there felt like a joke, as if it was a bit of cardboard bouncing around.
This gave me very intense, "big" sound - and made it easy to hear defects ... the process of further optimising became so much easier.
That looks more like an Aguirre helmet.
(for the Francophile Kinski lovers : https://www.youtube.com/watch?v=N7nSd5fkR1M )
IN this age of hightech there is absolutely no reason a loudspeaker needs to be outrageously heavy.
The patent here is 1996 (and goes to show USPO will grant a patent for anything). Its time to get with the times.
Patent US5949033 - Constrained layer damped loudspeaker enclosure - Google Patents
The patent here is 1996 (and goes to show USPO will grant a patent for anything). Its time to get with the times.
Patent US5949033 - Constrained layer damped loudspeaker enclosure - Google Patents
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