LeifB60 I now have very good experience with the 10.2 and 10.3 Gold.
The price is also good for the performance and sound / built quality.
The price is also good for the performance and sound / built quality.
I always uses high density and heavy quality mdf. It's more heavier and dead materiaal then plywood. So also in this case I'll use it.
Heavier is not an asset, and MDF is not dead, it absorbs and then oozes it out as time smeared low-level grunge.
dave
dave
Plywood Okoume 500kg/m3.
MDF HD 700kg/m3.
I prefer last one 2 x 18mm icw 28mm solid oak side panels.
But you can use what you want.
MDF HD 700kg/m3.
I prefer last one 2 x 18mm icw 28mm solid oak side panels.
But you can use what you want.
The best sounding speakers I've heard so far have all been plywood with no exceptions, and with lots of internal bracing.
Lead takes things in the opposite direction as you want. MDF needs morre bracing then plywood.
dave
dave
Correct, Lead damps mid en highs.
The Lhotse is one big bracing.
And plywood is much lighter than mdf.
But you can use plywood if you want.
But my advice to add extra weight to the panels if you uses plywood.
I strongly recommended NOT to add any bracing in a Lhotse cabinet.
The Lhotse is one big bracing.
And plywood is much lighter than mdf.
But you can use plywood if you want.
But my advice to add extra weight to the panels if you uses plywood.
I strongly recommended NOT to add any bracing in a Lhotse cabinet.
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Mass isn't a virtue in itself. For a given panel rigidity it simply lowers Fs and Q, so you have to keep in mind where that might end up putting it. By and large, the material's MOE / rigidity is more significant, with mass following, although they are of course connected for given material types.
Okoume plywood isn't a type I would normally suggest for speaker building. It's a decent material for other purposes, like boat-building when in marine form, but its (purposefully) lower mass / density & more importantly less rigid than something like a quality grade baltic birch of equivalent thickness, as well as being softer & with fewer laminations for a given thickness (so fewer internal boundary losses). In this appliction HDF, especially in doubled thickness will likely be as good or better, but a decent baltic birch should be superior to either with a higher MOE. Since rigidity of a given material increases to the cube of thickness, depending on grade you generally need about 1 1/8in - 1 1/4in of a quality grade MDF to equal high grade 3/4in BB plywood; with HDF that average becomes about 1in, give or take. As Dave says, the issue with MDF is that compared to, say, a quality Baltic birch ply, it's of a highish mass, but not especially rigid for a given thickness, often dropping Fs & its immediate harmonics toward the box operating region where the maximum amount of energy is available to excite it. So it either needs to be used in greater thicknesses, and / or with more bracing than a decent grade of Baltic birch or an equivalently rigid void-free multiply.
Since the front / rear baffles in Lhotse are doubled & it's a single driver design, a high grade MDF / HDF doubled should be sufficiently rigid & be a reasonable 'affordable' option, although the suggested quality grade of multiply like Baltic birch is preferable in performance terms, albeit at a significant increase in cost. Regarding bracing, as I say in the design notes: 'bracing not shown but recommended'. It's not vital, as it should be a fairly quiet structure, but it will benefit if you want to to put the extra work in. Because it's already quite rigid with the doubled panels, you don't need to go to the same lengths as with single-skin types, but some longitudinally oriented pieces wouldn't go amiss.
Okoume plywood isn't a type I would normally suggest for speaker building. It's a decent material for other purposes, like boat-building when in marine form, but its (purposefully) lower mass / density & more importantly less rigid than something like a quality grade baltic birch of equivalent thickness, as well as being softer & with fewer laminations for a given thickness (so fewer internal boundary losses). In this appliction HDF, especially in doubled thickness will likely be as good or better, but a decent baltic birch should be superior to either with a higher MOE. Since rigidity of a given material increases to the cube of thickness, depending on grade you generally need about 1 1/8in - 1 1/4in of a quality grade MDF to equal high grade 3/4in BB plywood; with HDF that average becomes about 1in, give or take. As Dave says, the issue with MDF is that compared to, say, a quality Baltic birch ply, it's of a highish mass, but not especially rigid for a given thickness, often dropping Fs & its immediate harmonics toward the box operating region where the maximum amount of energy is available to excite it. So it either needs to be used in greater thicknesses, and / or with more bracing than a decent grade of Baltic birch or an equivalently rigid void-free multiply.
Since the front / rear baffles in Lhotse are doubled & it's a single driver design, a high grade MDF / HDF doubled should be sufficiently rigid & be a reasonable 'affordable' option, although the suggested quality grade of multiply like Baltic birch is preferable in performance terms, albeit at a significant increase in cost. Regarding bracing, as I say in the design notes: 'bracing not shown but recommended'. It's not vital, as it should be a fairly quiet structure, but it will benefit if you want to to put the extra work in. Because it's already quite rigid with the doubled panels, you don't need to go to the same lengths as with single-skin types, but some longitudinally oriented pieces wouldn't go amiss.
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Thx Scottmoose,
I'll use 2x 18mm mdf (hd) 700kg/m3 👍 icw 28 solid oak side panels 😍.
All together solid glued to each other 💪.
No bracing will be added..... 😀so the internal space will be complete clean for optimum working conditions for the MAOP👌.
I'll use 2x 18mm mdf (hd) 700kg/m3 👍 icw 28 solid oak side panels 😍.
All together solid glued to each other 💪.
No bracing will be added..... 😀so the internal space will be complete clean for optimum working conditions for the MAOP👌.
As I say, I would add some longitudinally oriented front-rear bracing strips since you're using MDF. It's not vital, & you wouldn't need many, but it will bring a few extra performance points. That's my recommendation, as it's designer, FWIW.
Except for maybe the lower mids, not where it is needed. Lead increases mass without incrrasing stiffness so puishes resonances down where they are both more likely to be heard and more likely tobe excited.
Lightness is an asset.
I wouldn’t build without at least a holey brace to brace driver to back of the box.
dave
Hi Planed10, no bracing will be added in the Lhotse cabinets here.
Cabinets will be fabricated with heavy materials.
As I said:
Bracing in such a small internal section (165x127mm) will bring nothing.
You only will disturbing the working conditions for the MAOP in this design.
My advice not to do it.
Keep these beauties as clean as possible, also inside cabinet.
Cabinets will be fabricated with heavy materials.
As I said:
Bracing in such a small internal section (165x127mm) will bring nothing.
You only will disturbing the working conditions for the MAOP in this design.
My advice not to do it.
Keep these beauties as clean as possible, also inside cabinet.
If using high-quality wood, one way to go could be to apply luthier techniques with thin veneer on a lightweight skeleton, a la guitar body or similar.
Vibration is then controlled in 2 ways. 1, by adding mass to the magnet, so the amplitude is low to start with. The 2nd, could be to radiate it out into the air, like an actuator vibrating a lightweight board. Extra 'spokes' could be added, connecting the magnet with the back, rather than just the front. A problem with thick wooden walls is that the energy still makes its way out, it's just a question of when. The thickness also add an extra dimension for vibrations to bounce around in. Just my 2c.
Vibration is then controlled in 2 ways. 1, by adding mass to the magnet, so the amplitude is low to start with. The 2nd, could be to radiate it out into the air, like an actuator vibrating a lightweight board. Extra 'spokes' could be added, connecting the magnet with the back, rather than just the front. A problem with thick wooden walls is that the energy still makes its way out, it's just a question of when. The thickness also add an extra dimension for vibrations to bounce around in. Just my 2c.
You seem to be telling me (and announcing generally) that you know more about my own design and its operating characteristics than I do. Right-o... 😉
Wry humour aside, at the risk of both speaking factually, and repeating myself: light longitudinal bracing is accounted for (and recommended by muggins here as its designer) in the design. Nothing is 'disturbed'. I could have drawn it with a full set of longitudinal holey bracing, which would actually be ideal, but overkill given the structure & its proportions, and somewhat beyond my limited drawing skills. In the same way, ideally I would have drawn it assuming, say, 14ga cold rolled steel, ribbed aluminium or sheet aerolam rather than wood-based materials, which would result in slightly different external dimensions & have different internal bracing requirements, but metal fabrication or construction methods are beyond most DIYers (including me) so I don't often sketch boxes that way, even though they're technically higher performance options.
People are free to build as they want, obviously, and as I've noted, the bracing is optional since it isn't critical for good results. However, some mild longitudinal braces (e.g. one coupling the rear of the driver to the rear baffle as Dave notes) certainly do not do any harm, and in fact bring some small performance gains.
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