| Kofi Annan |
OK-- this is a really dumb one, but its a chance for someone to help a moron in need and openly ridicule him at the same time.
Today, I have been cutting wood for the Fostex 103E cabinets. Since the measurements are in millimeters and we in the USA still cling to the Imperial measurement system, I made all of my measurements in millimeters as well to avoid measurement issues when converting from metric to Ye Olde English.
Here's the problem: the cabinets call for 15mm thick wood and, of course, I only have 3/4", which roughly translates into 19.05mm so... TOO THICK!!
OK, Kofi, this should be no problem, right? All you have to do is add 4.05mm (well, 4mm) to all the thickness measurements and ensure that the inner dimensions stay the same and you're home, right?!?
If I try this, I won't be able to get the internal dimensions to remain the same since some of the wood is laying flat and the thicknesses will increase the size of the box pretty significantly. Also, for me (with pencil and paper) its REALLY, REALLY complicated.
So, I'm a dumbass and here are my dumbass questions:
Is there an easier way to get to the correct dimensions using 3/4" MDF? Does it matter more if the dimensions are proportionally correct (i.e., as long as the inner workings are the same size IN RELATION TO one another, their actual size does not matter) or must they be exactly correct?
I'm thinking one of you has some really cool software that can do this conversion like zzzzzzzzzzzzzzzzzzzing! Please say that's true.
Please help. Please. For the sake of my marriage.
Kofi |
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| Timn8ter |
| In my box building experience (which has been riddled with error) I've found that to get it right requires drawing out everything and making a cut list. Don't feel stupid. I know cabinet makers with decades of experience that can't build a simple six sided box without a detailed drawing and cut list. |
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| Kofi Annan |
Thanks. I appreciate the encouragement.
I've gotten a few of these RS 1170 drivers and I wanted to try my hand at a variety of enclosures. Dave (Planet 10) was kind enough to clarify the pipe on your website, so I'll be buidling that shortly as well.
Do you think I should keep the dimensions proportional or exact when accommodating the 3/4" MDF?
Kofi |
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| Timn8ter |
| Try to stay as close as possible to the internal dimensions described. It isn't a problem if you're off a little bit. The way those Fostex plans are it would be best to redraw them with the front and side plans then make your cut list. I don't know of an easier way to do it. The problem is when you change one measurement it affects all the others. You could always switch to 1/2" birch or appleply. :xeye: |
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| sreten |
Well width wise its as least not an issue.
Side on on its a 8 x 10 block puzzle with 32mm needed
adding to depth and 40mm needed adding to hieght.
If you define each vertical point and horizontal point as part
of this 8x10 puzzle its fairly easy to work out the new sizes,
assuming 4mm for each block crossed.
Of course getting it wrong will be extremely frustrating,
so check and check again you've worked it out right.
:) sreten. |
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| Paradise_Ice |
| 4mm out! thats nothing! you can fill the extra air space with some wadding, i always build the boxes bigger just incase they dont sound right, you can always take fill away but you cant add air space ones its made, unless you know what a tardise is?:grouphug: |
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| sreten |
| quote: | Originally posted by Paradise_Ice
4mm out! thats nothing! you can fill the extra air space with some wadding, i always build the boxes bigger just incase they dont sound right, you can always take fill away but you cant add air space ones its made, unless you know what a tardise is?:grouphug: |
I agree 4mm is nothing for one panel but is this case following
the cutting layout for 15mm panels will cause some serious grief.
For example the pointless multilayered mid baffle will be 16mm
out and the section referenced to the rear panel a further 8mm.
24mm out in a tapered horn is nowhere near "nothing".
(not that I think its good tapered horn design, it isn't)
:) sreten. |
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| Kofi Annan |
| quote: | | Try to stay as close as possible to the internal dimensions described. It isn't a problem if you're off a little bit. |
Yeah... I'll actually wind up off a little bit, but its good to know its a livaeble situation.
| quote: | Side on on its a 8 x 10 block puzzle with 32mm needed adding to depth and 40mm needed adding to hieght.
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That's what I camp up with too. Thank God.
| quote: | | Of course getting it wrong will be extremely frustrating |
I will get it wrong and it will be frustrating when it happens. Fortunately, there's always beer.
| quote: | | I agree 4mm is nothing for one panel but is this case following the cutting layout for 15mm panels will cause some serious grief. |
Yep. For evey horizonal panel I cross vertically and vice versa, I'll be 4mm off. It would just get worse and worse. Just like life under the Bush administration.
Well, at least you have all confirmed my worst fears. Looks like I'll be calculating and recalculating for a while to get this right. OK, maybe tonight I drink. Tomorrow I calculate.
V-A-C-A-T-I-O-N!!!
Kofi |
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| Dozuki |
Not sure how much of a shop you have, but I would save the frustration on converting this into 3/4 thickness and opt out for some 5/8 MDF (or better 15mm), Well, actually I would use solid stock and plane it down to 15mm since we have a planer in the shop that would do it, that and I ABORE MDF, its the nasiest stuff i've worked with in 17 years as a carpenter. But finding some sort of ply or MDF matieral of the right thickness might save you a huge headache in the long run.
However, if i were to build this from 3/4, I would scale it up (or down to be precise) on paper and refigure the whole thing for the thickness of the stock I was using. Not an easy task, but not an overly complicated one. i would also approach it from the perspective of looking at each internal 'run' in the horn being a specific size and dimension, reconfiguring the layout so these internal dimensions remained the same. Making a cut list from this would probably be helpful, but I would just note the new size of every piece on the new scaled drawing and cut from that. But, that is just the way that I work. With the way that this horn is constructed you wouldn't really have to mess with the width, only the depth and the height to accomidate the different thickness of the stock.
You might check some of your local lumber yards (ones that supply material for higher end homes) or some of the woodwork speciality stores like WoodCrafters as they might be able to get you MDF or Baltic Birch Ply in 15mm. I actually some some half sheets at a local Mom and Pop woodworking store around the cormer from me.
Good Luck and keep us posted.
-Dozuki |
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| BrianGT |
| quote: | Originally posted by Kofi Annan
OK-- this is a really dumb one, but its a chance for someone to help a moron in need and openly ridicule him at the same time.
Today, I have been cutting wood for the Fostex 103E cabinets. Since the measurements are in millimeters and we in the USA still cling to the Imperial measurement system, I made all of my measurements in millimeters as well to avoid measurement issues when converting from metric to Ye Olde English.
Here's the problem: the cabinets call for 15mm thick wood and, of course, I only have 3/4", which roughly translates into 19.05mm so... TOO THICK!!
OK, Kofi, this should be no problem, right? All you have to do is add 4.05mm (well, 4mm) to all the thickness measurements and ensure that the inner dimensions stay the same and you're home, right?!?
If I try this, I won't be able to get the internal dimensions to remain the same since some of the wood is laying flat and the thicknesses will increase the size of the box pretty significantly. Also, for me (with pencil and paper) its REALLY, REALLY complicated.
So, I'm a dumbass and here are my dumbass questions:
Is there an easier way to get to the correct dimensions using 3/4" MDF? Does it matter more if the dimensions are proportionally correct (i.e., as long as the inner workings are the same size IN RELATION TO one another, their actual size does not matter) or must they be exactly correct?
I'm thinking one of you has some really cool software that can do this conversion like zzzzzzzzzzzzzzzzzzzing! Please say that's true.
Please help. Please. For the sake of my marriage.
Kofi |
Kofi,
The easiest solution is to just pick up some 5/8" thick mdf. I happen to know a great place that carries it in Atlanta, called Atlanta Wood Products:
http://www.hardwoodweb.com/company/awpc.cfm
I would call ahead to see if they have it in stock if you are able to go there, as it is quite a far distance for you to travel.
When you get in there, they have a price list that you should pick up to see what is going on. I attached a screenshot of the mdf pricing part of the price list from the last time I went there. They also carry about 4 grades of mdf. I bought the top grade last time for my speakers, and it is much better than the home depot stuff. It was called PanFiberExcelPlus, and was $26.88 for a 4'x8' sheet of 3/4" mdf. I am not sure of the grades they have for 5/8"
Good luck with your project. I would just use the 5/8" mdf and you should almost be able to fully follow the plan with some unit conversions and sanity checks.
BTW: I finally bought a house last week, and it is about 4 miles from this place, and I move in on July 15th. Thanks for the advice.
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Brian |
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| Kofi Annan |
| quote: | | I happen to know a great place that carries it in Atlanta, called Atlanta Wood Products |
Always with the great advice. You know I'll be there tomorrow.
| quote: | | I would just use the 5/8" mdf and you should almost be able to fully follow the plan with some unit conversions and sanity checks. |
Will do.
| quote: | | I finally bought a house last week, and it is about 4 miles from this place, and I move in on July 15th. |
Congratulations! Homeowership is great. Glad to hear that you'll be out of apartment life. Hope you keep making great stuff and I wish you and the Mrs. lots of luck.
By the way, let me know if you need help moving. Its the least I can do. Well, the least I can do is abosolutely nothing, but this would be one better than that.
I'll start the project anew tomorrow and I'll post something when I cut my forking arms off. At least, I'll dictate to the wife and she'll post.
Kofi |
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| navin |
| quote: | Originally posted by Kofi Annan
That's what I camp up with too. Thank God. |
32mmD, 44mm H, 8mm W.
32mmD - 2, 21, 22, 10, 4, 8, 12, 13
44mm H - 14, 16, 17, 18, 19, 20, 11, 3, 7, 6, 5
8mm W - 1, 15. |
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| Josephjcole |
I also am stuck working in inches and have been forced to convert some of the fostex recomended enclousures to use 3/4" wood. I always just increased the outside demensions slightly, then you should be able to get everything pretty close. Just try to keep everything up right on as far as you can. A small difference at the mouth of the horn is no big deal, while the same difference could cause problems at the throat. But maybe you've already got 5/8" by now, in which case my advice is irrelevant :xeye:
oh well
Joe |
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| Kofi Annan |
My brain is about to explode.
The reason I'm making the smaller horn with the 103E is that I have some 206Es on order and I wanted to make the Fostex-recommended horns for those. In other words, my experiment with the 103Es was a dry run for the 206Es and I can see now that this is going to get really ugly.
Anyone got a design for the 206E drivers in Imperial / English measurements? If so, I can stop this nonsense and build Tim's voigt pipes and use another design for the 206Es when I receive them.
YYYYYEEEEEEAAAAAAARRRRRGGGGGHHHHHHH!!!!!!!!!
Kofi |
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| BrianGT |
| quote: | Originally posted by Kofi Annan
My brain is about to explode.
The reason I'm making the smaller horn with the 103E is that I have some 206Es on order and I wanted to make the Fostex-recommended horns for those. In other words, my experiment with the 103Es was a dry run for the 206Es and I can see now that this is going to get really ugly.
Anyone got a design for the 206E drivers in Imperial / English measurements? If so, I can stop this nonsense and build Tim's voigt pipes and use another design for the 206Es when I receive them.
YYYYYEEEEEEAAAAAAARRRRRGGGGGHHHHHHH!!!!!!!!!
Kofi |
Try not to explode, but if you look at the 206e fostex enclosure, they are using 21mm thick wood for that...
A great alternative, which I have seen recommended on another forum, would be to build the 208ez enclosure:
http://www.madisound.com/208ez_enclrev.pdf
It uses 18mm thick wood, which corresponds close enough to 3/4", and is said to be a much better design and will work with the 206e.
I think building the 103e enclosure with 5/8" would be good practice first though.
Another design to look at:
http://home.hetnet.nl/~geenius/Solo206.html
--
Brian |
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| Kofi Annan |
OK.... OK.... Kofi's feeling better now. I called AWP and they have 5/8" MDF. I'll be running by there tomorrow to get some.
With the 103E design, I'll be out .875mm for each board if I use 5/8", but I'm thinking that won't amount to much in the end. I should be able, as you have described, fully follow the plan. If I compromise on the dimensions of the internal spaces, I'm thinking I'll be out about a millimeter or so per gap. That's not the end of the world, right?
Also, I should still be able to use my 3/4" MDF for the external portion of the cabinet. This would seriously cut down on the amount of wasted wood product.
| quote: | | A great alternative, which I have seen recommended on another forum, would be to build the 208ez enclosure |
That sounds like a plan.
| quote: | | It uses 18mm thick wood, which corresponds close enough to 3/4", and is said to be a much better design and will work with the 206e. |
Yeah! This is the one I'll build for the 206E then. Again, I'll be off about 1mm per gap, but hopefully that will still work out OK.
Thanks again!
Kofi |
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| Greg B |
Personally, I would just build the thing from 5/8" particle board and stop worrying. It's not a big box. Beaverboard will work fine and is readily availabe in 5/8". Plywood is common in 5/8" as well, but it needs to be void free. BTW, ply is typically undersized, and nominal 5/8" likely *will* be 15 mm.
You can always sheath the thing with hardwood or plywood if the box sings too much.
GB |
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| Dozuki |
| Also, consider the size of 1mm. It isnt a whole lot, little more than a pencil line. 5/8 should work fine for 15mm without any reconfiguation. If you can build a box sized down to the exact mm then you are a better carpenter than I or have a lot more time on your hands :) |
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| Kofi Annan |
| quote: | | If you can build a box sized down to the exact mm then you are a better carpenter than I or have a lot more time on your hands |
Been measuring my stock with an electron microscope. 1mm is HUGE on the atomic scale. Now if I can just keep the dust mites and giant specks of pollen off the wood...
Thanks for all the advice. On my way to Atlanta Wood Products today.
Kofi |
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| BrianGT |
| quote: | Originally posted by Kofi Annan
Been measuring my stock with an electron microscope. 1mm is HUGE on the atomic scale. Now if I can just keep the dust mites and giant specks of pollen off the wood...
Thanks for all the advice. On my way to Atlanta Wood Products today.
Kofi |
Good luck. I am curious to see how the backloaded horns will sound.
--
Brian |
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| dvdwmth |
Im so glad you posted this question because I was about to go down the same path and I had the same worries.
streten seems to think this isn't a great horn design and the metric issue is a pain. Can someone suggest another plan for those of us who would like to try something similar with the fe103 or rs 40-1197?
Good luck getting that thing together Kofi |
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| Josephjcole |
| quote: | Originally posted by dvdwmth
streten seems to think this isn't a great horn design and the metric issue is a pain. Can someone suggest another plan for those of us who would like to try something similar with the fe103 or rs 40-1197?
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first of, no offense to Kofi there (I would hate to **** off such a respected world leader;) ) but it should not take you that long to convert it to 3/4". Just make the outside larger to fit the extra width of the plywood. Keep everything near the throat exact, and if you need a to drop or add a couple of mm at the mouth, no big deal.
second, streten did not say if he had heard them or not, but those who have seem to be quite happy. I've never built the recommended enclosure for the 103, but I have built one of the fostex designs based on the work of a Japanese man whose name escapes me at the moment. But if you do a little searching there are pages (in Japanese) with quite a few of his designs. I have built one and was quite impressed by it. I believe if you don't have the space or time for a full size backloaded horn, one of the fostex enclosures is a very good option.
I built the speaker you see in the picture which has been a lot of work, and lots of trial and error. I'm glad I did, I really enjoy them, but as far a sound quality I am not sure all the extra work , when compared to the relativly simple fostex enclosures, can be justified by sound quality alone. Of course I've never compared them side by side with a fostex design, this is simply by memory, so take it with a grain of salt.
Joe |
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| Kofi Annan |
| quote: | | first of, no offense to Kofi there (I would hate to **** off such a respected world leader ) but it should not take you that long to convert it to 3/4". |
Sure, Kofi, just drop eveything and convert 15mm to 3/4"!! Hey-- you think I don't have better things to do with the "handover" of Iraq in a couple of weeks? Jeez! Maybe we should just wait until mid-July so I can complete the conversion.
Started the horns today and everything is going as planned. I picked up some 5/8" MDF at Atlanta Wood Products and its going to be fine.
Also, they have some 18mm baltic birch, so I think I'll use that for the 206Es (using the 206E Sigma horn cabinets).
Will post pictures sometime tomorrow. Thanks to all for the help.
Kofi |
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| Dozuki |
nice :)
I've built the Fostex Double Bass Reflex for the FE83E, slightly modified the dimensions to fit a pair of Radio Shack clearance special speakers (full range dual cones, no info on the net about them and no T/S params, but CHEAP). I was actually quite impressed with the bass, Low bass is there, not powerfull, but there. Darn good considering the drivers. I use these for HT with the sub that came with the system (Cheap intigrated panasonic, and the sub is soon to be replaced) and a center channel that is an FE87 in a 2l box tuned to about 90. LOVE the center. I also have a couple FE166E's that are either going in the recomended horn or the the Fostex dbl bass reflex for the FE167, so I eagerly await your reports on the horns. I also have a couple FE83Es going into some 4l boxes tuned low for monitors. There are quite a few Japanese sites that have used these drivers and ppl seem quite fond of them.
Oh, and one modification that I have considered for the enclosure that you are building is to angle the fronts (45 deg. or better) of the pieces of wood in the bottom back of the enclosure (part #s 16-20) as well as 10, 22, 21, and the baffel so that at least the mouth of the horn is fairly smooth, and not as jagged. Not sure how much this will help, but I figgure it wouldn't hurt. I would also use a 1/4" roundover bit and roundover the parts that stick into the mouth to make these areas smoother as well (#5,8,9, and 12).
Anyway, keep us posted.
-D. |
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| dvdwmth |
| I just finished the small conventional enclosures fostex recommends for the fe 103 but using the RS driver. Even in these very small enclosures I was really impressed with how full the sound was and how much bass there is. I haven't even put in the ports yet. I cant wait to try them in a horn. |
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| Kofi Annan |
Just finished one horn and I think it sounds really great. Lots of detail and better bass than I was expecting.
Anyone know if stuffing this would increase bass response, or is it best to leave it alone? Unlike the other horn designs recommended by Fostex, there's no reference to any stuffing for the 103E design.
Any advice?
Kofi |
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| zobsky |
| quote: | Originally posted by dvdwmth
I just finished the small conventional enclosures fostex recommends for the fe 103 but using the RS driver. Even in these very small enclosures I was really impressed with how full the sound was and how much bass there is. I haven't even put in the ports yet. I cant wait to try them in a horn. |
ah, .. another believer in the fostex sound,
beautiful midrange, dynamic, almost live sounding, ... a bit rude in some frequency ranges, ... but sure beat out a lot of other more expensive speakers, IMO |
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| BrianGT |
| quote: | Originally posted by Kofi Annan
Just finished one horn and I think it sounds really great. Lots of detail and better bass than I was expecting.
Anyone know if stuffing this would increase bass response, or is it best to leave it alone? Unlike the other horn designs recommended by Fostex, there's no reference to any stuffing for the 103E design.
Any advice?
Kofi |
Any pictures?
The 208ez enclosure mentions stuffing.
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Brian |
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| Kofi Annan |
| quote: | | The 208ez enclosure mentions stuffing. |
Yeah, but the 103 enclosure doesn't. Should I stuff it and where should I stuff it?
The above is what comedians refer to as a "straight line"-- its normally meant to elicit a comical response. But seriously, I really do need to know where to stuff it. Can't someone please tell me where to stuff it? I'll stuff it anywhere! I'll stuff it!!
I'll have some pictures in a bit. Right now, I need to run to Ace to get some more screws and glue. I used lots of screws and glue. Lots. First I glued, then I screwed, then I glued the screws, then I screwed the glued screws.
| quote: | | ah, .. another believer in the fostex sound, beautiful midrange, dynamic, almost live sounding, ... a bit rude in some frequency ranges, ... but sure beat out a lot of other more expensive speakers |
Yep. I can't wait for my 206Es to arrive. They should sound significantly better than 103Es (I used the RS driver for the 103E cabinet too).
Kofi |
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| chris ma |
Great line here :D
"First I glued, then I screwed, then I glued the screws, then I screwed the glued screws." I screwed Amen
Chris |
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| Josephjcole |
Of course everybodys ear are different, but I have alway ended up with felt covering the majority of the walls in the filter chamber, leaving the stuffing out. I would definatly add the felt, then mess around with the stuffing if you want to see what happens.... maybe it will help, maybe not.....
Joe |
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| Kofi Annan |
| Finished the horns and I'm very pleased. Here are some pictures, as promised. |
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| Kofi Annan |
| And another... |
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| Kofi Annan |
Last one. I'm going to get some felt today to line some of the walls. I'm very happy with the bass output, but it sounds just a little "boxy", so I'm hoping the felt will help.
Also, there's a tiny bit of distortion in the highs, so I may see if I can get some of the custom phase plugs from Dave (Planet 10). Gotta do a little surgery to get those in place, but I may give it a shot.
Kofi |
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| Kofi Annan |
The Fostex 206Es I ordered some time ago are arriving today, according to UPS. I'll be building the 208EZ enclosure for them, as recommended by Brian GT.
I'll post pictures as the project progresses. Thanks for all the great advice.
Kofi |
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