Dear Godzilla, I will cut the angles with a Stanley plane and I will be using MDF Svein, the same as Colin used in his. I will not take the drawing to the Do It Yourself shed merely say, 'Eyup gi'us 6 140's and 2 750's out of an 8be4' the 100mm bit left at the end will take care of the 8 cuts.
I think the idea of Do It Yourself Gary and I do say this with the greatest respect is that you do as much as you can yourself, if that means for instance you have to use handtools to cut angles then so be it. If you've not done it before then try it first on some scrap timber, mark what you are going to cut carefully and make small even cuts. The one thing that we as Do It Yourself enthusiasts have is time, time to make a good job.
And as they say, 'Them as never made a mistake, never made anything' or you can always go and buy another piece
Jim
I think the idea of Do It Yourself Gary and I do say this with the greatest respect is that you do as much as you can yourself, if that means for instance you have to use handtools to cut angles then so be it. If you've not done it before then try it first on some scrap timber, mark what you are going to cut carefully and make small even cuts. The one thing that we as Do It Yourself enthusiasts have is time, time to make a good job.
And as they say, 'Them as never made a mistake, never made anything' or you can always go and buy another piece
Jim
I still don't understand all this emphasis on measurements. People use simulations to predict what they'll get (usually in low frequency response), and continue to use them because they tend to match what you hear. We wouldn't use simulation programs if we thought they were crap.
Chris
Dear Godzilla, I will cut the angles with a Stanley plane and I will be using MDF Svein, the same as Colin used in his. I will not take the drawing to the Do It Yourself shed merely say, 'Eyup gi'us 6 140's and 2 750's out of an 8be4' the 100mm bit left at the end will take care of the 8 cuts.
I think the idea of Do It Yourself Gary and I do say this with the greatest respect is that you do as much as you can yourself, if that means for instance you have to use handtools to cut angles then so be it. If you've not done it before then try it first on some scrap timber, mark what you are going to cut carefully and make small even cuts. The one thing that we as Do It Yourself enthusiasts have is time, time to make a good job.
And as they say, 'Them as never made a mistake, never made anything' or you can always go and buy another piece
Jim
You're right Jim about this being DIY, but the biggest hold up to most is the ability to break down a 4'x8' sheet of plywood. I think the easier that this project can be made for those just starting out the better. More will be willing to jump in and build a pair and hear the magic a fullranger can make.
Dear Gary,
I agree wholeheartedly this FH3 sounds wonderful, its lineage can be traced back to the original Busschorn [1983?] and it has come of age in this brilliant design.
My introduction to audio was listening to a [well off] work colleagues Lowther Acoustas about 40 years ago the FH3's are the sound I never thought I would hear again.
Warmest wishes - Jim
I agree wholeheartedly this FH3 sounds wonderful, its lineage can be traced back to the original Busschorn [1983?] and it has come of age in this brilliant design.
My introduction to audio was listening to a [well off] work colleagues Lowther Acoustas about 40 years ago the FH3's are the sound I never thought I would hear again.
Warmest wishes - Jim
Jemraid,
If you are going to make your Frugal Horns from MDF then you really need to use 18mm NOT 15mm. Also remember that the CHP70 drivers requires a 6mm deep rebate for mounting. So the front baffle, IMO, really needs to be 18mm thick for that driver.
The speakers you listened to were 18mm MDF mainly 'cos they were a beta build test pair and at the time I couldn't afford the extra cost of BB Ply.
Future builds will be either 15mm BB Ply with 18mm Front baffle or 18mm BB Ply throughout.
I know DaveD has the opinion that 18mm BB Ply is overkill on these cabinets but if one has to buy 2-sheets of ply (15mm for main carcass and 18mm for front baffle with recessed driver) then it makes econimic sense to me to just buy a single sheet 18mm. Where I buy my sheet wood they only sell full 8' x 4' sheets.
If one is to veneer cover the finished cabinets then using ply it doesn't really matter which way the grain is as each layer has opposite grain and the veneer covers the whole anyway.
If you are going to make your Frugal Horns from MDF then you really need to use 18mm NOT 15mm. Also remember that the CHP70 drivers requires a 6mm deep rebate for mounting. So the front baffle, IMO, really needs to be 18mm thick for that driver.
The speakers you listened to were 18mm MDF mainly 'cos they were a beta build test pair and at the time I couldn't afford the extra cost of BB Ply.
Future builds will be either 15mm BB Ply with 18mm Front baffle or 18mm BB Ply throughout.
I know DaveD has the opinion that 18mm BB Ply is overkill on these cabinets but if one has to buy 2-sheets of ply (15mm for main carcass and 18mm for front baffle with recessed driver) then it makes econimic sense to me to just buy a single sheet 18mm. Where I buy my sheet wood they only sell full 8' x 4' sheets.
If one is to veneer cover the finished cabinets then using ply it doesn't really matter which way the grain is as each layer has opposite grain and the veneer covers the whole anyway.
15mm MDF is not sufficient. 18mm is barely sufficient and not as good as 15mm baltic birch. I would strongly recommend plywood. Very strongly. You will not achieve the best rsults with MDF, and it needs to be thicker to achieve the required stiffness, but that leads to more time smeared energy, reducing potential downward dynamic range.
Colin does have a point with the baffles. Even with the CHP/CHR/EL70 and their dp rebate, 15mm is sufficient for the baffle leaving 9mm of meat. The plastic basket makes a difference here. For the Alpair7 we feel an 18 mm baffle is needed as the rebate is closer to 9mm. Hence we have choosen to go with 18mm baffles & 15mm elsewhere. Mark actually likes to se pople using thin baffles so as to minimize tunnel effect on the back of the driver. With a proper 45 degree champher on the back of the driver cutout i don't feel that a thicker baffle is a real issue in this respect. We are thou making 15 pairs and always have a project somewhere/sometime that can use the offcuts.
Using as much 15mm as possible makes sense in terms of shipping to keep the weight down. I was surprised at the post office with the packaged 15mm FH3 weighing almost as much as the FH1 12mm flatpak. I would worry about an all 18mm build exceeding the 30 kg limit Canada Post has -- not an issue if you don't have to ship them.
As to the 4x8 cutplan, it doesn't strike me as quite right. This based on being able to squeeze a pair of 15mm boxes into the 25 ft^2 of a 5x5 BB. with 48 ft^2 to work with there should be close to a half sheet left unused (to satisfy my curiousity, i will now go and draw my own cut plan -- which i need for the documentation anyway)
dave
Don't let being mad deter you from building FH3, you can't just have one speaker
The Needles use a 3" driver, Alpair6P would be more appropriate than the 2" Alpair5 (even if you could find some)
dave
Dear Dave,
It would have been a nice project from 15mm MDF easy to cut for people like me with unsophisticated tools who like to do as much as they can themselves. Alas my easy [for me] to cut, cutting diagram falls off the edge with 18mm. This as they say is what you find.
I knew it was Alpair something
Thanks for the idea of using a tuner through some drive units for burning them in slowly, I must do that with my little Tangbands.
Warm wishes - Jim
It would have been a nice project from 15mm MDF easy to cut for people like me with unsophisticated tools who like to do as much as they can themselves. Alas my easy [for me] to cut, cutting diagram falls off the edge with 18mm. This as they say is what you find.
I knew it was Alpair something
Thanks for the idea of using a tuner through some drive units for burning them in slowly, I must do that with my little Tangbands.
Warm wishes - Jim
OK, that was easy. It is already page 8 of the current document (25-oct-10). Not quite as much useable left overs as i expected
I will now go do an 18mm 4x8 cut, it is hard to think it won't fit on a single sheet.
And as expressed earlier, for all but the A7 15mm baffle is fine. If one is really worried about that, the driver can be surface mounted and the opportunity to laminate a piece of 6mm solid to the baffle to achieve a flush mount and a sexy look
dave
Let us know. If it comes down to finesse and pure midrange i know where i'd be betting
dave
I really want to hear a pair of Zu's... Having built simple sealed boxes for Beta 12's with great midrange results i wonder how the tricked out 10" Eminence driver sounds? I also want to hear a pair of FH3's in my listening room or office... i think both rooms would do really well with them. Has anyone directly compared the FH3 with the Hornshoppe?
Can't believe all the DIY fellows building speakers.
I'm getting a flat pak coming from Dave in the next few weeks and am totaly
excited to assemble the MK3's. I haven't built speakers since woodworking class in high school over 40 years ago.
After hearing a MkI frugal before christmas, I was blown away.
The fellow that got these MKI's has the same tube gear that I have and both systems I rebuilt had similar components, so the A/B test was easy,
so I had to go for a pair. And now that the MK3's are out they seem much more simpler to assemble.
I haven't dabbled in any DIY speaker or enclosures before, so I am a nubie.
I'm mainly into vintage tube restoration. The Eico HF81 seems to be the most popular these days and I bet I'm now into about my 20th unit to restore for a fellow
in Vancouver.
So I'll post next when I get my flat pack and start the assembly..can't wait!!!
I'm getting a flat pak coming from Dave in the next few weeks and am totaly
excited to assemble the MK3's. I haven't built speakers since woodworking class in high school over 40 years ago.
After hearing a MkI frugal before christmas, I was blown away.
The fellow that got these MKI's has the same tube gear that I have and both systems I rebuilt had similar components, so the A/B test was easy,
so I had to go for a pair. And now that the MK3's are out they seem much more simpler to assemble.
I haven't dabbled in any DIY speaker or enclosures before, so I am a nubie.
I'm mainly into vintage tube restoration. The Eico HF81 seems to be the most popular these days and I bet I'm now into about my 20th unit to restore for a fellow
in Vancouver.
So I'll post next when I get my flat pack and start the assembly..can't wait!!!