drvomir said:
Down below there I think somebody has a Sachiko in the build stage.
The usual advantages/disadvantages usually have to do with your room setup and so on to begin with. A few of the double horns have been built.
Maybe you can tell us a bit more about what you have and the desired result. Also music preferences can play a ro^le as well.
I've built the Sachiko with both the Fostex 206ESR driver and the stock Fostex 206E with Planet 10's phase plugs. Both were very good. I've also built the Saburo and IMO, it essentially boils down to personal preference over the 126E driver or 206E. They are both very emotionally engaging drivers.
I've decided to build, and have some questions.
EDIT: I've already ordered two Fostex 206E drivers from Madisound.
Among two drivers and a birch ply what else is required? Maybe wires, or binding posts....?
As for birch ply itself, is it acoustically preferable to not to have finish/color on them? Should the ply's surface be smoothest possible or something?
And also, I don't get what would the small two parts (in blue) represent. They are just next to driver on the Sachiko map.
Thanks
EDIT: I've already ordered two Fostex 206E drivers from Madisound.
Among two drivers and a birch ply what else is required? Maybe wires, or binding posts....?
As for birch ply itself, is it acoustically preferable to not to have finish/color on them? Should the ply's surface be smoothest possible or something?
And also, I don't get what would the small two parts (in blue) represent. They are just next to driver on the Sachiko map.
Thanks
Er... well, you could build a pair with no wire attached to the drivers, but they'd be terribly quiet. 
Silent in fact.
OK, abandoning the fairly obvious requirement for some speaker wire at the very least, people generally prefer to use what they like in terms of wire & posts, and place them where they like too. That's why we leave it to the end user to decide what they want to do -it's their project, so they can personalise such things to taste. FWIW, make sure the internal wire run isn't too long, which might cause rattling, and if you if you drill through any internal panels to route the wire, they'll need to be sealed to prevent leak paths.
The two blue extensions you mention are explained at the top left of pg.2 of the plans. They're just optional tongues of material, drilled to allow good airflow, extending forward to brace against the rear of the driver's motor.
Re the ply, & acoustic preferences, that's a massive can of worms. You might be able to measure extremely low level differences between different finishes, but you're not going to hear them. Just sand the face of the panels to ~400 grit if you feel so inclined (it's not a requirement), & then finish them as you see fit. I've very dubious indeed about the claims made about miracle-working finishes. They're not a musical instrument. They shouldn't be producing tones of their own in the first place; they should be reproducing the tones fed into them.
Wax over French polish looks nice. Terry Cain favoured rubbed polyurethene (will try to dig out his remarks). A really good violin varnish does look nice, though it has to be good.
Silent in fact. OK, abandoning the fairly obvious requirement for some speaker wire at the very least, people generally prefer to use what they like in terms of wire & posts, and place them where they like too. That's why we leave it to the end user to decide what they want to do -it's their project, so they can personalise such things to taste. FWIW, make sure the internal wire run isn't too long, which might cause rattling, and if you if you drill through any internal panels to route the wire, they'll need to be sealed to prevent leak paths.
The two blue extensions you mention are explained at the top left of pg.2 of the plans. They're just optional tongues of material, drilled to allow good airflow, extending forward to brace against the rear of the driver's motor.
Re the ply, & acoustic preferences, that's a massive can of worms. You might be able to measure extremely low level differences between different finishes, but you're not going to hear them. Just sand the face of the panels to ~400 grit if you feel so inclined (it's not a requirement), & then finish them as you see fit. I've very dubious indeed about the claims made about miracle-working finishes. They're not a musical instrument. They shouldn't be producing tones of their own in the first place; they should be reproducing the tones fed into them.
Wax over French polish looks nice. Terry Cain favoured rubbed polyurethene (will try to dig out his remarks). A really good violin varnish does look nice, though it has to be good.
drvomir said:
You'll need at least 2 feet of wire from the binding posts to the driver. I've found a little longer than necessary makes hook up easier. You could also wire direct to the driver, but that makes speaker wire testing a bit difficult.
Smooth birch is good as you won't spend as much time and money on sandpaper before finishing them.
Whether it is acoustically preferable not to have a finish, that would be a great thread to start. I've used polycrylic and stain on most of mine, but often wondered if I used a violin varnish, or linseed oil, would they sound different?
If the cabinets vibrate even a little bit, aren't they imparting their own sound and tone? Wouldn't an MDF horn, or one built of gypsum board sound different than a Maple Ply horn? Even though the goal is for the cabinet not to impart its own tone, I don't see how it can be avoided in a cabinet so huge as the Sachiko. One of my sachiko builds was made from Birch and painted black. The second was made from Maple and the front covered with Mahogany veneer then covered with seven coats of polycrylic. Both were heard in the same room. The Maple had a much more lively and quick sound. The painted birch had great sound, but not as lively. Not sure if this was due to the paint/finish or the type of wood however, but the gentleman I built them for made the same observations.
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Indeed it is, although I believe that most really good luthiers these days generally regard the varnish as adding only the last few percentage points. http://www.instrumentmaking.keithhillharpsichords.com/hillviolinvarnish.html
Having said that, I do have a copy somewhere of an article showing full CAT (or whatever) electrionic scans of a number of Strad., Guarneri & Amati instruments, showing the materials, their density, thicknessess etc., & they were nothing particularly special in this particular respect, so the authors decided once again to look at the varnish. Square one again. Then again, as I mentioned above, we're not creating an instrument here, but a reproducer, so it's a bit of a moot point WRT it's properties on a violin / viola / cello / whatever. They were designed with the behaviour of BB ply in mind, so changing it to a material with different MOE values will naturally affect the sound. MDF is to be avoided like one of the minor Biblical plagues. Some stable, tight-& long grain solid woods, such as the maple you used in one build, are fine; they will need a modification in thickness to ~match the birch ply assuming you want it to behave in the intended fashion. It's an impossibilty to remove all cabinet resonances, as I've been pointing out for a long time. Controlling them is all that can be done, preferably by pushing them up, above the cabinet's operating BW to a place they are unlikely to be excited.
Just dug out Terry's old finishing remarks, in response to the following query he got:
>Which would be the better choice for speaker cabinets with 4 mm Baltic Birch sides and easier to maintain for the long term? Yes, I am anal retentive and really love wood. TIA.
On birch I like a lighter look than tung oil. The air will darken birch nicely after a year or so regardless. Tung oil is very durable and fine for darker woods like gunstocks etc. but birch goes blotchy a bit. A better goo is polyurethane (oil based, Sherwin Williams or any oil based varnish gloss) mixed 60%poly-40%mineral spirits (maybe stiffer weather permitting) with min spirits and applied like a tung oil. Brush on and wipe off about 3-8 coats (24 hrs between coats min) sanding with 320 grit on a padded block. Then use a nice beeswax diluted into min spirits (shave the beeswax with a chisel a few days ahead)add lilac or juniper oil maybe some cheap perfume. Apply wax with #0000 steel wool and buff with cotton. And you have a faux French polish that will wear better than shellac. Has a stronger film against abrasion and moisture than tung. Smells good too. Basicall this is Simon Watts and Jason La Trobe Bateman's finnish, cabinetmakers to the Rothchilds, drawers and furniture etc. Some of the better Italian finishers inspect the cotton seed feilds the varnish is squished from, Varnish-o-philes. TC
Having said that, I do have a copy somewhere of an article showing full CAT (or whatever) electrionic scans of a number of Strad., Guarneri & Amati instruments, showing the materials, their density, thicknessess etc., & they were nothing particularly special in this particular respect, so the authors decided once again to look at the varnish.
Square one again. Then again, as I mentioned above, we're not creating an instrument here, but a reproducer, so it's a bit of a moot point WRT it's properties on a violin / viola / cello / whatever. They were designed with the behaviour of BB ply in mind, so changing it to a material with different MOE values will naturally affect the sound. MDF is to be avoided like one of the minor Biblical plagues. Some stable, tight-& long grain solid woods, such as the maple you used in one build, are fine; they will need a modification in thickness to ~match the birch ply assuming you want it to behave in the intended fashion. It's an impossibilty to remove all cabinet resonances, as I've been pointing out for a long time. Controlling them is all that can be done, preferably by pushing them up, above the cabinet's operating BW to a place they are unlikely to be excited. Just dug out Terry's old finishing remarks, in response to the following query he got:
>Which would be the better choice for speaker cabinets with 4 mm Baltic Birch sides and easier to maintain for the long term? Yes, I am anal retentive and really love wood. TIA.
On birch I like a lighter look than tung oil. The air will darken birch nicely after a year or so regardless. Tung oil is very durable and fine for darker woods like gunstocks etc. but birch goes blotchy a bit. A better goo is polyurethane (oil based, Sherwin Williams or any oil based varnish gloss) mixed 60%poly-40%mineral spirits (maybe stiffer weather permitting) with min spirits and applied like a tung oil. Brush on and wipe off about 3-8 coats (24 hrs between coats min) sanding with 320 grit on a padded block. Then use a nice beeswax diluted into min spirits (shave the beeswax with a chisel a few days ahead)add lilac or juniper oil maybe some cheap perfume. Apply wax with #0000 steel wool and buff with cotton. And you have a faux French polish that will wear better than shellac. Has a stronger film against abrasion and moisture than tung. Smells good too. Basicall this is Simon Watts and Jason La Trobe Bateman's finnish, cabinetmakers to the Rothchilds, drawers and furniture etc. Some of the better Italian finishers inspect the cotton seed feilds the varnish is squished from, Varnish-o-philes. TC
Great information there Scottmoose and much of which I have never read before. I had no idea that your cabinets were designed with Baltic Birch in mind.
I certainly find it all a fascinating subject for conversation. (As do others it seems due to all the books written about the subject) I will argue one point to the grave with you though......YOUR designs are indeed "musical instruments" to my ears!!!
I owe about the last two years of my musical enjoyment (and woodworking relaxation) to you and Planet 10.
I certainly find it all a fascinating subject for conversation. (As do others it seems due to all the books written about the subject) I will argue one point to the grave with you though......YOUR designs are indeed "musical instruments" to my ears!!!
I owe about the last two years of my musical enjoyment (and woodworking relaxation) to you and Planet 10.
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Glad you found it useful.
They are, but fairly approximately -I'm not a materials expert by any stretch of the imagination. For e.g. I learned something new about MDF myself only the other day & its resonant properties (which further confirmed my dislike of it as a material). If that stuff is used for my series / manifold expansion cabinets at any rate, then the panels will generally need doubling to 1 1/4in - 1 1/2in thickness to match the stiffness of BB; controling its resonance behaviour though is still harder than for the ply & it will probably require some additional cross-bracing to try & prevent it from resonanting in the cabinet's BW.
Solid woods I know little about at all; I gather white oak, properly dried, is very good, as are maple, alder & possibly purpleheart. Walnut is also supposed to be useful in some apps. The Japanese like pine & spruce, again, properly dried, & again, I believe they are supposed to offer an excellent stiffness / weight ratio, with easily managed resonant behaviour. Good for horns, apparantly, although I've never looked into it & I suspect they're actually using it to provide a degree of colouration. Cheap particle / chipboard can be quite effective -I prefer it to MDF, although it's a PITA to work with given its propensity for crumbling & my inept building skills (I can hold a saw on a good day & that's about it). I'm just throwing out quick thoughts here almost at random though, before I have to trudle out to get some blank DVDs (just realised I've run out) so they're hardly profound / new. They all have their different behaviours that need to be worked with.
As do I. Maybe it's time for a dedicated thread on the subject, discussing materials generally for use with FR drivers (usually discussions on materials tend to focus solely upon BB vs MDF, so a broarder ranging thread might be of interest to a lot of people)
I will argue one point to the grave with you though......YOUR designs are indeed "musical instruments" to my ears!!!
I owe about the last two years of my musical enjoyment (and woodworking relaxation) to you and Planet 10.
Well, thank you.
Glad you've enjoyed them. I really should get around to sorting that Spawn page out at some point. It could do with a bit of a pruning / re-organise. Maybe make one or two modifications; replace a cabinet or two with updated ones I've had on the drawing board.
if the blue extensions are omitted from the box, would a "face plate" board on the front (outside) of the cabinet suffice?
Blimey, another vampire thread (back from the dead).
Yes. You don't really need to do that either, it's fine just mounting the driver. Last few percentage points.
I really do need to update this familiy of boxes for the En series units. Well, actually, I already have, but there aren't enough hours in the day to get the plans revised.
I'm not Derek, but IIRC it was maple plywood.
Yes. You don't really need to do that either, it's fine just mounting the driver. Last few percentage points.
I really do need to update this familiy of boxes for the En series units. Well, actually, I already have, but there aren't enough hours in the day to get the plans revised.
I'm not Derek, but IIRC it was maple plywood.
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