So, guys, what kind of sweet spot do these FF165 BiBs throw? How well do they perform off axis?
In the living room, there's very little sweet spot sitting. If I got these near ear height in a BiB, then I would generally be sitting a couple degrees off from the right speak and maybe close to 15 degrees off of the left. My wife (who likes to view from a more curled up position) would be the opposite, but also 5+degrees off vertically, too.
Kensai
In the living room, there's very little sweet spot sitting. If I got these near ear height in a BiB, then I would generally be sitting a couple degrees off from the right speak and maybe close to 15 degrees off of the left. My wife (who likes to view from a more curled up position) would be the opposite, but also 5+degrees off vertically, too.
Kensai
wood turners question
I've got a specific build question.
I have glued all the cabinets together for my BIB (168EZ). Next step is to get a wood turner to make the supra baffles.
I have made a few enquiries and first of all, wood turners are hard to find! The other problem I'm facing is that they have all said that a turned peice of solid wood like we are using for supra baffles will move and distort enough to buckle the driver. No one wants to do the job and risk me coming back in a few weeks complaining.
Enough of these things have been made. Even some in damp old UK, so do the move? Is there an issue with warping wood?
The suggestions I am getting are to let the wood sit for 6 months in my living room to really settle down, before turning it!
I suppose I could just use some offcuts from the birch ply, which might look quite interesting due to the layers being exposed.
I did have a wonderful burr elm bowl blank sorted, but everyone I have talked to has said that elm is one of the worst woods for twisting...
Help please
I've got a specific build question.
I have glued all the cabinets together for my BIB (168EZ). Next step is to get a wood turner to make the supra baffles.
I have made a few enquiries and first of all, wood turners are hard to find! The other problem I'm facing is that they have all said that a turned peice of solid wood like we are using for supra baffles will move and distort enough to buckle the driver. No one wants to do the job and risk me coming back in a few weeks complaining.
Enough of these things have been made. Even some in damp old UK, so do the move? Is there an issue with warping wood?
The suggestions I am getting are to let the wood sit for 6 months in my living room to really settle down, before turning it!
I suppose I could just use some offcuts from the birch ply, which might look quite interesting due to the layers being exposed.
I did have a wonderful burr elm bowl blank sorted, but everyone I have talked to has said that elm is one of the worst woods for twisting...
Help please
Greets!
Any of these should be hard enough with low enough moisture content:
Lignum Vitae = 77
Kingwood = 70 to 75
Cocobolo = 61 to 75
Tulipwood = 65
Pau Ferro = 50 to 60
Honduras Rosewood = 60
Goncalo Alves = 59
Bubinga = 55
Wenge = 55
Purpleheart = 54
Brazilian and Indian Rosewood = 53
Persimmon = 52
Hickory = 51 (great for building Hedlunds using
Hickory veneers!)
Madrone = 48
White Oak = 47 (also good for Hedlunds using White
Oak veneers!)
Pecan = 46
Padauk = 45
Pear = 44
American Birch = 43
Baltic or European Birch = 41
Hackberry = 40
Red Oak = 40
Teak = 40
Most of the Walnuts (American, English, French, etc.) = 40
White Ash = 42
Imbuia = 41
Hard Maple = 40
GM
Any of these should be hard enough with low enough moisture content:
Lignum Vitae = 77
Kingwood = 70 to 75
Cocobolo = 61 to 75
Tulipwood = 65
Pau Ferro = 50 to 60
Honduras Rosewood = 60
Goncalo Alves = 59
Bubinga = 55
Wenge = 55
Purpleheart = 54
Brazilian and Indian Rosewood = 53
Persimmon = 52
Hickory = 51 (great for building Hedlunds using
Hickory veneers!)
Madrone = 48
White Oak = 47 (also good for Hedlunds using White
Oak veneers!)
Pecan = 46
Padauk = 45
Pear = 44
American Birch = 43
Baltic or European Birch = 41
Hackberry = 40
Red Oak = 40
Teak = 40
Most of the Walnuts (American, English, French, etc.) = 40
White Ash = 42
Imbuia = 41
Hard Maple = 40
GM
Hi Martin
Bending or warping is a real problem with solid wood. I used solid wood couple decades ago which ended up in disaster 2-3 months after completion.
Trick is to make a gluebord where you turn the year rings on the opposite of each other. Also the moisture content should be around 7-11%. Then the lacquering has to be done on both sides to avoid tensions. (Oil not so bad but still...) Everyone who has lacqured a solid table top probably seen the tremendous forces lacquer can put on wood.
Difficult to say, but in the pictures of Terry Cain's speakers it looks like he has made them from four pieces glued together. That's something maybe an owner of these could tell.
I'm surprised non of your turners could do this, or maybe it's not so profitable to make two small pieces...
Last choice for you would be to buy some plywood, turn four pieces. (Hmm, wonder if it is possible with plywood!)
Two pieces should be the same diameter as the diameter of the start of the "rounding" of the baffle
Why four pieces? Use one on top and one under so you are covering the flat surfaces of the one in the middle.
Spray primer to fill up eventuall voids or pores with a suitable colour, black or....
Get them to a turner who has a widebelt sander and sand off overspray from front and back. Or sweat it out by hand, great work out
Clear lacquer front and back and you have a quite stunning effect of wood and colour on the edges.
Sorry for the misuse of your language but hope you understand at least half of the gibberish
Good luck!
Peter
Bending or warping is a real problem with solid wood. I used solid wood couple decades ago which ended up in disaster 2-3 months after completion.
Trick is to make a gluebord where you turn the year rings on the opposite of each other. Also the moisture content should be around 7-11%. Then the lacquering has to be done on both sides to avoid tensions. (Oil not so bad but still...) Everyone who has lacqured a solid table top probably seen the tremendous forces lacquer can put on wood.
Difficult to say, but in the pictures of Terry Cain's speakers it looks like he has made them from four pieces glued together. That's something maybe an owner of these could tell.
I'm surprised non of your turners could do this, or maybe it's not so profitable to make two small pieces...
Last choice for you would be to buy some plywood, turn four pieces. (Hmm, wonder if it is possible with plywood!)
Two pieces should be the same diameter as the diameter of the start of the "rounding" of the baffle
Why four pieces? Use one on top and one under so you are covering the flat surfaces of the one in the middle.
Spray primer to fill up eventuall voids or pores with a suitable colour, black or....
Get them to a turner who has a widebelt sander and sand off overspray from front and back. Or sweat it out by hand, great work out
Clear lacquer front and back and you have a quite stunning effect of wood and colour on the edges.
Sorry for the misuse of your language but hope you understand at least half of the gibberish
Good luck!
Peter
Wow, thanks for the list. Quite a lot of wood seems to be suitable.
I am a bit of a enviro conscious type and would rather source wood that is UK based. That said I do have a wood suppliers near to me and I know they have English walnut. I have oak here but it has been stored in an outside wooden shed and so I guess would be too high moisture content to use immediately?
I guess the best things in life come to those who wait
I am a bit of a enviro conscious type and would rather source wood that is UK based. That said I do have a wood suppliers near to me and I know they have English walnut. I have oak here but it has been stored in an outside wooden shed and so I guess would be too high moisture content to use immediately?
I guess the best things in life come to those who wait
Peter
Thanks for the idea. I am not quite sure I completely get it. Do you mean have one piece of ply that you will keep and another piece that will be placed where the driver will sit and will get part turned, and thrown away? Once it is removed then the flat area is left, ready to mount the driver on.
As for the spray idea. Did you mean it to have a sprayed edge when finished, but the area that was covered remains birch ply?
Sorry if I just suffereing from late night sleep deprivation. It has been a long day...
Thanks for the idea. I am not quite sure I completely get it. Do you mean have one piece of ply that you will keep and another piece that will be placed where the driver will sit and will get part turned, and thrown away? Once it is removed then the flat area is left, ready to mount the driver on.
As for the spray idea. Did you mean it to have a sprayed edge when finished, but the area that was covered remains birch ply?
Sorry if I just suffereing from late night sleep deprivation. It has been a long day...
If you don't want the timber to warp, and are looking for an environmentally friendly solution, you should try to find some recycled hardwood. It should be well dried out, which is when most warping occurs. The trick would be to complete the machining and seal the timber immediately to prevent any absobtion of moisture, which may swell the timber slightly.
If you can't find any recycled timber locally, then butt jointing smaller pieces together makes for a very stable board (butchers block), especially if biscuit joined and glued. As peterbrorsson mentioned, run the grain rings in different directions, to avoid cumulative warping.
If you can't find any recycled timber locally, then butt jointing smaller pieces together makes for a very stable board (butchers block), especially if biscuit joined and glued. As peterbrorsson mentioned, run the grain rings in different directions, to avoid cumulative warping.
Hi Martin!
You put the piece you want to use, which have the requested size, in the middle in order to protect the flat back and front.
Like the cheese'n'ham in a sandwich.
Reuse them for the second baffle
And yes, here you throw away the bread and keep the cheese'n'ham!
Come to think about it.. You have IKEA in the UK I presume?
They have kitchen benches in beach and oak with garanteed moister content. Quite reasonable prices also. Lot of speaker builders use these panels in Sweden.
Cheers
Peter
You put the piece you want to use, which have the requested size, in the middle in order to protect the flat back and front.
Like the cheese'n'ham in a sandwich.
Reuse them for the second baffle
And yes, here you throw away the bread and keep the cheese'n'ham!
Come to think about it.. You have IKEA in the UK I presume?
They have kitchen benches in beach and oak with garanteed moister content. Quite reasonable prices also. Lot of speaker builders use these panels in Sweden.
Cheers
Peter
peterbrorsson said:
Greets!
Sorry, forgot to copy/paste what the numbers mean, they are lbs/ft^3 density, so are quite dense, hence can't retain much moisture. Of course the higher the number the better, though the woods at the top of the list would be quite hard to cut/shape.
If I just wanted some out of hardwood, I'd buy a couple of wood kitchen carving boards to cut the blanks from. These can withstand being soaked in soapy water or washed in the dishwasher without splitting or popping a glue joint.
GM
IKEA has everything you would ever need to build baffles from. Their HOL hardwood hampers make great W shape bass baffles. Their laminated hardwood tabletops have been used hundreds of times for OB purposes.
I personally would follow exactly what Greg is suggesting, find the nice Maple butcherblock and cut for 13 inch blanks, with 1 inch thickness. This was exactly the Rx TC wrote to me for the 6.5 driver. Tung oiled hard Maple looks the business.
I personally would follow exactly what Greg is suggesting, find the nice Maple butcherblock and cut for 13 inch blanks, with 1 inch thickness. This was exactly the Rx TC wrote to me for the 6.5 driver. Tung oiled hard Maple looks the business.
Hi!
What do you make of these? Helmholtz compensation for the dip at 150Hz?
http://www.flo-horns.de/Flo13/Flo13.htm
Cheers
Peter
What do you make of these? Helmholtz compensation for the dip at 150Hz?
http://www.flo-horns.de/Flo13/Flo13.htm
Cheers
Peter
Re the link provided by Peter brorsson and the german horn or BIB or whatever it is. I remember suggesting that such a resonator might be made in the bass of the BIB in the early days of the monster BIB thread.
Unfortunately I can't build one as yet but I am pleased to see that a similar idea has been carried out I think several people agreed at the time that it might have possibilities. I have tried to find ways to simulate this with some lateral thinking on the programmes I have but no luck.
I think the guys who built the replikon has a similar absorber idea on the thread where they suggested, and provided a spreadsheet for, another way to build or calculate a transmission line. My understanding is the absorber is a stuffed resonator. I mean the cavity and port is worked out the same way.
jamikl
Unfortunately I can't build one as yet but I am pleased to see that a similar idea has been carried out I think several people agreed at the time that it might have possibilities. I have tried to find ways to simulate this with some lateral thinking on the programmes I have but no luck.
I think the guys who built the replikon has a similar absorber idea on the thread where they suggested, and provided a spreadsheet for, another way to build or calculate a transmission line. My understanding is the absorber is a stuffed resonator. I mean the cavity and port is worked out the same way.
jamikl
jamikl said:
Use of a helmholtz resonator to kill some of the resonant peaks has become quite popular with the German hobby magazines. I 1st was exposed to the idea by the author/builder of the TLb in about 2k. I've not yet run across the idea in any of the early literature (but i suspect it is there).
I've not tried it myself -- something about it just doesn't sit right with me.
dave
Greets!
IIRC I read about them in one of Olson's books, but it's in his late '30 BLH patent. I think I'm going to change my sig line to be 'those who don't learn from history are doomed to repeat it' since the pioneers of audio didn't leave much for future generations to invent without altering physics as we know it.
That said, when I was hot n' heavy into experimentation I never did figure out a rule-of-thumb to design them, so spent my time on ways around needing them, which had other trade-offs to deal with and ultimately lost interest in BLHs since I could get better performance overall with one or more LF drivers in MLTLs or Voigt style pipes combined with either a 'FR' driver or large mid/HF FLH.
GM
IIRC I read about them in one of Olson's books, but it's in his late '30 BLH patent. I think I'm going to change my sig line to be 'those who don't learn from history are doomed to repeat it' since the pioneers of audio didn't leave much for future generations to invent without altering physics as we know it.
That said, when I was hot n' heavy into experimentation I never did figure out a rule-of-thumb to design them, so spent my time on ways around needing them, which had other trade-offs to deal with and ultimately lost interest in BLHs since I could get better performance overall with one or more LF drivers in MLTLs or Voigt style pipes combined with either a 'FR' driver or large mid/HF FLH.
GM