Loudspeakers As Musical Instruments is a romantic notion (and that's not intended in a pejorative sense). What's the target? LAMIs will, presumably, work best for some music at the expense of others.So much personal preference comes into play, it makes the finished product a very individual instrument - which is okay for the sort of bespoke, individual work most of us DIYers are doing.
A true monitor speaker, on the other hand, shouldn't emphasise any type of music or sound at the expense of any other, within its given passband. To achieve that, you choose the most appropriate materials for the size, weight and expense of cabinet and use the most appropriate building techniques. MDF boxes will probably require different bracing and damping techniques to plywood but once done I doubt you'd hear a difference.
This article (PDF) is interesting on the development of one of the Harbeth monitors.
A true monitor speaker, on the other hand, shouldn't emphasise any type of music or sound at the expense of any other, within its given passband. To achieve that, you choose the most appropriate materials for the size, weight and expense of cabinet and use the most appropriate building techniques. MDF boxes will probably require different bracing and damping techniques to plywood but once done I doubt you'd hear a difference.
This article (PDF) is interesting on the development of one of the Harbeth monitors.
Colin said:
I think the problem with this subject is that it becomes guessing soon. You can only discuss it if every one who participates really heard the differences we talk about.
My loudspeaker (which is a resonance box) is built after ten years experimenting with different kinds of woods, constructions, bracings etc.. (no unwanted resonances there anymore!) But now it's there... it can handle far more different music styles then for instance the Audio Physic Caldera, Avalons etc. and in a way more musical sense. But again: that's something we can't discuss, you should hear it. That was also the only way to kick the sceptism out of me 😉
Nice article Colin, I've read somthing similar regarding the LS3, interesting about listening to peach to ***** some aspects of a speakers output.
I'm now wondering about open baffles (never heard one) in regards to earlier points about box colorations adding to the sound etc or not, I have heard then described as having an open sound, not boxy etc. What would a speaker on the absolute minimum sized baffle (ie enough to hold the driver solidly), with some form of baf curtain behind to absorb rear reflections, sound like?
MJL21193, I bet it fun when your crew bus is loaded up with yor team and sheets of 2x4 sheathing (obviously 8x4 would be harder to balance. Least its green transport🙂
I'm now wondering about open baffles (never heard one) in regards to earlier points about box colorations adding to the sound etc or not, I have heard then described as having an open sound, not boxy etc. What would a speaker on the absolute minimum sized baffle (ie enough to hold the driver solidly), with some form of baf curtain behind to absorb rear reflections, sound like?
MJL21193, I bet it fun when your crew bus is loaded up with yor team and sheets of 2x4 sheathing (obviously 8x4 would be harder to balance. Least its green transport🙂
Quick link for you reMC, a violin made as a speaker, or a speaker made using luther techniques that looks like a violin.
http://www.rolfeandhandy.co.uk/carl_handy_dalis_violin_I.htm#
http://www.rolfeandhandy.co.uk/carl_handy_dalis_violin_I.htm#
marce said:
The reason i prefer plywood, is that it allows me to build boxes that don't sing. MDF boxes are dead, because all the time delayed low level hash they emit (energy storage) obscure the really subtle bits... the part of the music that gives us a lot of clues as to what is happening.
So just to reiterate... MDF sounds dead because it is not dead.
dave
Hi Marce - The Harbeth site has some other good articles on the BBC design approach. In a way (he said, backtracking), it comes close to the instrument approach to loudspeaker design in that the cabinet design is fine tuned to a specific response, albeit one which aims to gives the listener an accurate reproduction of a range of material. And some of the tuning is counter-intuitive, such as fixing the back panel with screws so that it remains lossy.
I originally looked at the site to see if Harbeth now use MDF but no, they seem to be continuing to use thin-wall birch plywood.
I originally looked at the site to see if Harbeth now use MDF but no, they seem to be continuing to use thin-wall birch plywood.
"Mina rushes to confort Lucy as she falls back in a dead faint as
Van Helsing anounces that Quincy and Arthur are duelling over the best
material to build a harpichord."
"ye gods" he cries "surely MDF cant be that Vlad"
🙂
Van Helsing anounces that Quincy and Arthur are duelling over the best
material to build a harpichord."
"ye gods" he cries "surely MDF cant be that Vlad"
🙂
😀
In fairness, I have a suspicion that bad cabinet design has caused more problems than cabinet materials ever have. If you design a duff enclosure, you'll get duff sound, whatever it's made from. A good design will always be a good design, and can only improve with optimal selection of materials (whatever 'optimal' might be for the design goals).
But to use my current example, my current 167 MLTLs in birch ply are to my ears far superior to my earlier MDF boxes, and it's not just down to the narrow front baffle used this time & phase plugs, which have improved the imaging to a startling extent. It's Ed's the superb construction (thanks again Ed -these things are going to be with me for a very long time 🙂) and the materials used. Its in the lower-level detail that things seem that much cleaner. Self-fulfilling prophesy because I expected the ply to be better? Possibly. But I don't think so; I've heard a lot of MLTLs & 167s, so I know what I'm listening to.
In fairness, I have a suspicion that bad cabinet design has caused more problems than cabinet materials ever have. If you design a duff enclosure, you'll get duff sound, whatever it's made from. A good design will always be a good design, and can only improve with optimal selection of materials (whatever 'optimal' might be for the design goals).
But to use my current example, my current 167 MLTLs in birch ply are to my ears far superior to my earlier MDF boxes, and it's not just down to the narrow front baffle used this time & phase plugs, which have improved the imaging to a startling extent. It's Ed's the superb construction (thanks again Ed -these things are going to be with me for a very long time 🙂) and the materials used. Its in the lower-level detail that things seem that much cleaner. Self-fulfilling prophesy because I expected the ply to be better? Possibly. But I don't think so; I've heard a lot of MLTLs & 167s, so I know what I'm listening to.
No doubt.
Hello everyone, I really enjoy this conversation. I’m having fun reading on your “badinage”.
I find all of you great minded people indeed. 😉
I read accurately almost every post here and I grown my idea about many things about MDF, Ply and solid… and glues also. 😀
Glues… well I use yellow glue… but is it really yellow glue? Here, in Europe, they call this glue yellow glue because of the bottle, the bottle is yellow, and the glue is white. But the glue is PU or poly-urethane… And… there is another brand, yellow bottled glue which is really yellowish or brownish but it is still PU… Another kind of glue for wood is vinyl white glue or poly vinyl tetra chloride… This could be real white glue… I supposed…
But there is an entire kind of glues, those named bi-components based on epoxy resin or PVC resin which are not water based glues.
Which one should be better for loudspeakers? Who knows.
But the topic was not the glue rather than the wood… was it?
Well, I may be sick of physics but let’s consider the phenomena this way:
Let’s take a piece of wood, let’s suppose ply, 1’x1’x1”, take a microphone and a digital storage oscilloscope, suspend the piece o wood someway and via a coil excite it at all the frequencies in the audio range. You will find the natural oscillation frequency and many of their harmonics. Just to make an example 345Hz. Get another piece of wood same size but MDF you could find that the natural frequency in changed to 238Hz. Same size, but solid mahogany, you may find a natural oscillation frequency of 487Hz (just guessing). Now, glue together by one side two of these pieces of wood, same size same material what you’ll find out? The natural resonance frequency are summed? Nope, they are halved. No there is no way to know? Yes, there’s a way. Math analysis, finite element analysis. But in any case the frequency will be lower than that measured for one piece. Usually for a same dimension piece of wood (or anything else) you will find that the natural resonant frequency and therefore their harmonics will be lower if the material is heavier, softer, dense, porous, humid; higher if the material is lighter, harder, dry, etc… Lets drill a hole in the middle. You’ll find not only that the natural frequency is shifted higher but you may find another natural frequency with the frequency strictly related to the diameter of the hole. Now, lets make the same experiments changing glue kind, and see what happens. The conclusion is, the cabinet for your loudspeaker must have a resonant or natural oscillation frequency in the audio band or not? I think it will absolutely not.
And the way to avoid this happens is to use the bracing, glues, wood type, dimensions, holes, painting, amulets, and holy water as appropriate. So, It’s my opinion that a kind of wood could be better than other because it is good looking, more resistant to moist, to hits, to nuclear radiations, to wife or whatever but if the enclosure does not “oscillate” or vibrate if you like the term it should not interfere with the sound of the speaker less than it can if you are talking about a horn or a bass reflex but this is not wood dependent.
A wood or material mass dependency is sound speed in solids. But this was said at the beginning of the thread, I recall, and this will change the way waves in the garbled cabinet travels, in that a sense the cabinet is like a music instrument, like a piano, a guitar o any using a cabinet or a chest to couple the strings oscillation, the speaker in our case, to the air, to match impedance. As the horn speaker is like a brass. So, a speaker is really a musical instrument, but it is not the resonant type, and it should not be. A glue is not at all. 😀
Cheers
Larry.
Hi Larry - that test is more or less what the BBC paper undertook, so classic BBC speakers use a thin-walled enclosure, mass-loaded to push its resonant frequency to the LF where the ear will be less sensitive to it.
Hi Scott - agree about cabinet construction techniques. I also wonder if the type of cabinet may not have an influence. I remember a Martin Colloms review of the German horns ...eurgh, forgotten the name but they look like the Oris. Anyway, he said they revamped their materials specifically so the horn would flex slightly because it sounded better.
So perhaps horns and TLs sound better using one material, whereas simpler enclosures, which are easier to apply the mass is best school of construction, can be made to work with MDF.
Interesting topic with a lot of black and white answers being bandied about but it's undoubtably more complicated (and fascinating) than that.
Hi Scott - agree about cabinet construction techniques. I also wonder if the type of cabinet may not have an influence. I remember a Martin Colloms review of the German horns ...eurgh, forgotten the name but they look like the Oris. Anyway, he said they revamped their materials specifically so the horn would flex slightly because it sounded better.
So perhaps horns and TLs sound better using one material, whereas simpler enclosures, which are easier to apply the mass is best school of construction, can be made to work with MDF.
Interesting topic with a lot of black and white answers being bandied about but it's undoubtably more complicated (and fascinating) than that.
Oh yes, the optimal natural material is certainly going to vary depending on cabinet type & intentions. I still want to try something from 14ga CRS though.
John and Dave,
I will add to the rant regarding houses. I owned a house in Sweden that was built of 25 cm diameter logs. That's what I call a house, period! Also the flooring, as the inner walls, were made of 5 cm thick, hard, aged and properly dried pine. The walls were covered with some 2.5 cm porous fibre boards.
The living room where I had my instruments and stereo was by far, the best room I ever had until now.
What to make loudspeakers of, I leave it to the horses, they have bigger heads, Ergo, must be smarter😎
BTW John, your "crew" is in my taste😀
Cheers
Peter
EDIT:House was built 1898
I will add to the rant regarding houses. I owned a house in Sweden that was built of 25 cm diameter logs. That's what I call a house, period! Also the flooring, as the inner walls, were made of 5 cm thick, hard, aged and properly dried pine. The walls were covered with some 2.5 cm porous fibre boards.
The living room where I had my instruments and stereo was by far, the best room I ever had until now.
What to make loudspeakers of, I leave it to the horses, they have bigger heads, Ergo, must be smarter😎
BTW John, your "crew" is in my taste😀
Cheers
Peter
EDIT:House was built 1898
Mass-loaded enclosure, is that to increase the weight of the enclosere? What method, if so, would be the best way to achieve that goal, if not by "fatter" enclosure walls?
Scottmoose said:
This is exactly my point. Good design + good drivers + good crossovers + good equipment + good source material + good room acoustics = good sound.
NOT Good plywood + good driver basket damping + no crossover + good interconnects/cables + good disc clamp for turntable + thick window curtains = good sound.
There are lots of small tweaks one can do to improve a speakers performance, but the question is, by how much?
Larry Lomax said:
Not the glue again. I understand that there is a bit of a terminology difference between here (North America) and the rest of the world, but this is different. I see a lot of brand names used here, like Titebond.Titebond makes yellow carpenter's glue.
Elmer's makes yellow carpenter's glue.
LePage makes yellow carpenter's glue.
Surely, you must recognize one of these.
It's simple really.
MJL21193 said:
...Though the first 3 (& possibly the last point depending on the room) of the second set mean that, combined with a good cabinet design, you'll get very good sound indeed for many types of music.
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