Probably is. WRT the wooden backing of early iron armour in mid 19th century naval vessels, they found significantly improved resistive properties for the same thickness when built from a greater number of thinner layers. Should be something similar here.
planet10 said:
Medite is not known in Australia as far as I can tell. However, I dug up the Sierrapine website which has several grades of Medite fibreboard and not one of them has the density of Laminex HD3.
http://www.sierrapine.com/products/mdf.htm
While I can't locate technical data for raw 18mm HD3 I have found a product sheet for laminated HD3 http://www.mitchellgroup.com.au/dev...s/temp/Mitchell Laminates - hd3_decorated.pdf
As you will see Laminex HD3 has a density of 1200kg/cuM against something like 770kg/cuM for the best of Sierrapine's Medite range.
I can attest to HD3 being the hardest fibreboard in existence since it blunts any woodworking tool in far less time than other MDF grades. If you accidentally knock the edge of HD3 you can chip off a sliver much like it would be on a piece of fine china - no furry edges on the chipped edge to indicate it is even made of wood, just a clean semi-circular edged chip of solid hard material. Because it is used only for the most rugged environments it doesn't enjoy the benefit of volume production cost savings and that is why it costs so much more than the more commonly available and popular MDF grades.
Probably is. WRT the wooden backing of early iron armour in mid 19th century naval vessels, they found significantly improved resistive properties for the same thickness when built from a greater number of thinner layers. Should be something similar here.
Anytime an energy has to encounter a new interface of a different medium with different properties there is a greater loss of the effective energy than thru a monocromatic medium, given the same total mass. There is a calculated loss at the interface. Even the grain structure (we discussed this Scott in steels) changes the attenuation factor greatly.
Energy hates interfaces because they make it weaker.
ron
Anytime an energy has to encounter a new interface of a different medium with different properties there is a greater loss of the effective energy than thru a monocromatic medium, given the same total mass. There is a calculated loss at the interface. Even the grain structure (we discussed this Scott in steels) changes the attenuation factor greatly.
Energy hates interfaces because they make it weaker.
ron
On the cost of Laminex HD3:
Trade price quoted for Laminex 2400 x 1800 x 18 sheet of raw HD3 is AUD410.00 plus 10% sales tax. A single sheet weighs 93.3kg (just over 205lb).
Trade price quoted for Laminex 2400 x 1800 x 18 sheet of raw HD3 is AUD410.00 plus 10% sales tax. A single sheet weighs 93.3kg (just over 205lb).
Here's a link to an interview with PHY-HP, a famous producer of wide-band units.
http://6moons.com/industryfeatures/phy/phy.html
MDF is mentioned also...
http://6moons.com/industryfeatures/phy/phy.html
MDF is mentioned also...
Scottmoose said:
Hi Scott - the stuff in B&Q isn't brilliant quality.
I've bought ply sheets from Travis Perkins and they are competitive. You can ask for a trade card, which gets you free delivery on 8x4 sheets. Whilst you're at it, ask for a copy of their sheet materials booklet - some useful info although not all branches stock the full range. It may be on their website as a download.
Colin (living in the north but an unrepentant southerner)
reMC said:
This was a very interesting interview. It truly plumbs the depth of one mans psychotic obsession.
Quote from the article regarding MDF:
" For a delightfully simple demonstration, Salabert placed a wind-up music box mechanism on a raw sheet of MDF, then low-grade ply. Needless to say, the MDF destroyed both tone and signal amplitude to clearly sound inferior and quieter to the ply when Bernard began turning the crank. In free air, the sound was attenuated even further and downright washed out. Within this simple experiment hides the foundation why Ocellia for example employs PHY drivers in thin-walled Spruce Ply cabinets (Spruce is commonly used in guitar bodies and regarded as a tone wood"
A music box mechanism needs a soundboard to amplify and accentuate it's sound. A soundboard is: "the part of an instrument that transmits the vibrations to the air, greatly increasing the loudness of sound".
If you want your speaker to be as a musical instrument, to resonate and colour the original music, then avoid MDF. It's not musical enough.
BTW, these PHy drivers are rather expensive - $1800.00 for a 12".
Ah yes, but a mere 200 Euro for an 8" ceramic magnet/stamped basket unit soon to be released.
I do like the fact that the man has an undeniable passion and looks beyond the graphs. Sure beats cable dielectric discussions.
Apologies to jneutron and others.
I do like the fact that the man has an undeniable passion and looks beyond the graphs. Sure beats cable dielectric discussions.
Apologies to jneutron and others.
and I suspect that is all down to differences in the natural damping (Q) of the material.MJL21193 said:
If you WANT the box to resonate then use high Q.
If you NEED silence from the box, then low Q is closer to what is required.
If the box says, "I'm going to be heard, no matter what you do to try and silence me" then I suspect that the higher Q might sound nicer
MJL21193 said:
So what? The better the driver quality, the more expensive they tend to be, as is right and proper. Especially with WR drivers, which are a heck of a lot harder to engineer than a driver with a substantially narrower passband, like the average midbass.
That figure is about $250 per unit more than an 8in Lowther PM4; not bad for a much larger unit that appears to be considerably better built (without meaning to sound down on my native product, build quality & consistancy are not exactly the first words that leap to mind when discussing Lowthers). From what I've seen about them, there is little voodoo involved; it's just good solid engineering. When you think about how much people would pay for Altec drivers back in the 1960s, and compare the relative prices, there isn't much difference. I can't afford the existing PHY units myself, but the asking price is reasonable enough, especially given the economies of scale involved in the small production runs.
AndrewT said:
It's one philosophy pitted against the other: speaker as a musical instrument versus speaker as a musical reproduction instrument.
I like the idea of the speaker giving an accurate representation of the original music. In order to make that happen, you have to use all of the methods at your disposal to reduce box emissions, and rely on the drivers to provide the sound uncoloured.
You are correct, of course, it's nearly impossible to completely eliminate sound emissions from the enclosure, but you can reduce these to a point where you will not hear them over the music.
Scottmoose said:
Hi Scott,
So what?? I have my own personal rule about drivers: I will not spend more than $250.00 on a single driver. It's not that I can't afford it, it's because there isn't one in production today that is worth more than that.
These PHy drivers are, at the end of the day, just drivers. Sure, the basket is bronze - it looks pretty. Yeah, the voice coil is wound inside the former as well as the outside and with silver wire (like that makes a lick of difference). Oh, and the motor is so special.
Yet, he is willing to abandon these high dollar features to produce a low cost driver with steel basket, ceramic magnet and copper voice coil. Surely, this will be a completely mundane, mediocre effort without all of the lofty features of the original.
Looks like he is selling out his high ideals. Getting sick of starving to death, I guess.
AndrewT said:
Andrew, that is far too simplistic a view.
A resonance needs energy concentrated in its bandwidth to excite it. If you have a high Q resonance and the resonance is pushed high enuff (energy available to exite is approx inversly proportional to the square of the frequency), then that resonance is silent because it will not be excited (unless you regularily thwack your speakers with a screw-driver).
dave
MJL21193 said:
My ideal box is totally silent... and 35 years of building speakers has got me to a box where panel resonances are both high in Q and high in frequency and do not get excited. The proof is in the pudding. My best box just dissapears, and has downward dynamic range in spades (i good sign that time delayed low level grunge has been minimized -- the very thing that makes an MDF box a non-strater for me)
dave
planet10 said:
Hi Dave,
You make the assumption that the only way to build a box with MDF is to drive resonances downward. All of the same tricks you use to drive panel resonances up with plywood work just as well with MDF.
You talk about the "energy storage" problem that MDF has, like it's a big brown battery. Energy storage is no more of a problem for MDF than it is for plywood. If there is any difference between these two materials sonics wise, then I have to say that MDF has the edge, due to it's inherent self-damping capacity (as demonstrated with the music box mechanism).
Without dwelling on the technical side, I would like to look at this from a "sound" point of view.
I have had only two occasions to listen to identical systems with the cabinet material being the difference. Both times the plywood cabinet, which I agree should not add it's own colouration to the final product, simply sounded better. To me, it's not about the graphs or theories, it's about what your ears are happiest with. I am in agreement with those who choose plywood. To me, the MDF vs. plywood is reminiscent of the tube vs. solid state discussions. It really doesn't matter what you see on paper.
I have had only two occasions to listen to identical systems with the cabinet material being the difference. Both times the plywood cabinet, which I agree should not add it's own colouration to the final product, simply sounded better. To me, it's not about the graphs or theories, it's about what your ears are happiest with. I am in agreement with those who choose plywood. To me, the MDF vs. plywood is reminiscent of the tube vs. solid state discussions. It really doesn't matter what you see on paper.
MJL21193 said:
excellent description... you only forgot the "leaky" part
And since plywood is better damped than MDF?
dave
As this is on Full Range, I'm not sure. John makes some good points but I'm not sure how valid they are for horn speakers while Dave, Scott and Cal speak eloquently about the other side. I wonder if the 'true path' 🙂angel: like tube pre-amp with an SS power amp 
D)) is somewhere in between - like sidepanels of plywood and others using MDF.
Most of the BLH's I've heard have been fairly coloured in their sound, mostly in the lower registers. You can tell where the 'crossover is between the driver and the horn quite easily. Not to say they've been bad sounding, just not like real guitar or voice. Most of these have been made with plywood (what type I do not know) as you could see the edges showing. I don't think I've seen one made with MDF.
A lot of the FLH mids (I've never heard a full-range FLH) that I've heard have been fairly uncoloured, but all have been made of either turned MDF/HDF or moulded resin (generally fibreglass).
But I can only really tell whether the sound is similar of different to the original when I'm playing stuff I've recorded myself, and there's not a lot of that. I can make a guess when I take along some of my other stuff, but it's sometimes difficult to tell whether the speakers are then an improvement on what I usually listen to,... or just a change.
D)) is somewhere in between - like sidepanels of plywood and others using MDF.Most of the BLH's I've heard have been fairly coloured in their sound, mostly in the lower registers. You can tell where the 'crossover is between the driver and the horn quite easily. Not to say they've been bad sounding, just not like real guitar or voice. Most of these have been made with plywood (what type I do not know) as you could see the edges showing. I don't think I've seen one made with MDF.
A lot of the FLH mids (I've never heard a full-range FLH) that I've heard have been fairly uncoloured, but all have been made of either turned MDF/HDF or moulded resin (generally fibreglass).
But I can only really tell whether the sound is similar of different to the original when I'm playing stuff I've recorded myself, and there's not a lot of that. I can make a guess when I take along some of my other stuff, but it's sometimes difficult to tell whether the speakers are then an improvement on what I usually listen to,... or just a change.
MJL21193 said:
I assume, following your analogy, that you consider that a VW Golf has the same performance & quality as a Bentley Continental R, because they're both cars?
From your remark that no driver over $250 is worth more, I offer my congratulations sir. When you listened to every driver produced over $250, what were your impressions? What did you make of their physical construction and the design and engineering work that went into them? What specifically made each and every one no better than cheaper ranges from the same company (or others for that matter)? I look forward to your comprehensive reviews based on personal experience.
Back on planet Earth, have you followed up my suggestion & compared the relative price of a flagship Altec unit in the 1960s, against average contemporary earnings, to, a modern equivalent and average income today? As for PHY launching a cheaper range, what are you suggesting? Are they are the only company not allowed to have a top-end product and a less expensive series of drivers offering some of the performance of the pricier ones? I take it therefore that you believe that cheaper units from all companies equal the performance of their flagship products? We both know that's nonsense. Yes, there are stupidly over-priced products out there designed to part the gullible from their cash (just look at the hifi cable market for the worst example of them all), and there are plenty of high-end drivers that fall into that category. There are plenty that don't though.
Frankly, John, could you give it a rest please? I for one am getting more than a little tired of this game. I know what you're doing, you've blatently said it in other threads, which you tried to stir up for God only knows what reason. You seem to think it's your mission to come along and post 'controvertial' statments to make us think (little children, who can't do it for themselves). How very patronising. I've got news for you. We don't actually need it thank you. Oddly enough, some of us know what we're talking about.
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