Sounds like a description of Jon Risch's formula for cross connected cabling.
http://www.geocities.com/jonrisch/cables.htm
While a few years behind the bleeding edge of DIY hype/lore, and lacking a degree of webpage glitz, there's till some good technical information contained therein. He's done a fair degree of research and listening.
There are no doubt numerous other DIY (TNT U-Byte, etc) listand even commercial products using similar topologies - there's only so much time and bandwidth available for researching and building everything that's "possible".
Like so many tweakoid audio nervosa projects, the proof is in listening to the total system synergy, for which it's unlikely any conclusive predictor will ever be devised.
http://www.geocities.com/jonrisch/cables.htm
While a few years behind the bleeding edge of DIY hype/lore, and lacking a degree of webpage glitz, there's till some good technical information contained therein. He's done a fair degree of research and listening.
There are no doubt numerous other DIY (TNT U-Byte, etc) listand even commercial products using similar topologies - there's only so much time and bandwidth available for researching and building everything that's "possible".
Like so many tweakoid audio nervosa projects, the proof is in listening to the total system synergy, for which it's unlikely any conclusive predictor will ever be devised.
Martin,
on the matter of the concentric baffles, Terry Cain had recommended to me, that for the 6.5 drivers, (in this case the FE168EZ were the subject,) to use a diameter of ~13 inches, with a continuous, curved, slope to the expanding radius, to its edge, outside of the driver flange radius, obviously, and use 1 inch hardwood. I had a pair of Abbys at the time, and the effect is obvious. Albert's observations are exactly what I would have expected.
If you go to their website, www.cain-cain.com and study the shots of the I'm BEN, you can go from there.
on the matter of the concentric baffles, Terry Cain had recommended to me, that for the 6.5 drivers, (in this case the FE168EZ were the subject,) to use a diameter of ~13 inches, with a continuous, curved, slope to the expanding radius, to its edge, outside of the driver flange radius, obviously, and use 1 inch hardwood. I had a pair of Abbys at the time, and the effect is obvious. Albert's observations are exactly what I would have expected.
If you go to their website, www.cain-cain.com and study the shots of the I'm BEN, you can go from there.
Greets!
Seems like the easiest to do overall would be to calc/make a tractric profile based on a mouth radius of half whatever the material thickness is to use as a guide to rounding over the front/rear edge of the supra baffle. This way you can use whatever thickness you want and be assured it won't cause any undue diffractions.
GM
Seems like the easiest to do overall would be to calc/make a tractric profile based on a mouth radius of half whatever the material thickness is to use as a guide to rounding over the front/rear edge of the supra baffle. This way you can use whatever thickness you want and be assured it won't cause any undue diffractions.
GM
Hey Zayne and Chrisb,
I figured there would be some difference with the resistance and impedance....
Yeah, me and a friend of mine had been doing a bit of listening and that was the best....well for the speakers we were using at the time!!! The German fora seem to like it too. Darn that ELI!!! I've come across him researching my amp project....(thanks chrisb!)
Now here's something I just tried which has made a nice improvement to my BIB's!
I lined the last 40cm inside the horn (of course!) with some bubble wrap...yes bubble wrap! with the bubbly side out. My take on it is...it probably disperses the higher frequencies that make it that far. Imageing is better and the instruments seem to be better separated from each other.
If anyone has some sitting around give it a go. It costs nothing...practically.
Cheers Stroop
I figured there would be some difference with the resistance and impedance....
Yeah, me and a friend of mine had been doing a bit of listening and that was the best....well for the speakers we were using at the time!!! The German fora seem to like it too. Darn that ELI!!! I've come across him researching my amp project....(thanks chrisb!)
Now here's something I just tried which has made a nice improvement to my BIB's!
I lined the last 40cm inside the horn (of course!) with some bubble wrap...yes bubble wrap! with the bubbly side out. My take on it is...it probably disperses the higher frequencies that make it that far. Imageing is better and the instruments seem to be better separated from each other.
If anyone has some sitting around give it a go. It costs nothing...practically.
Cheers Stroop
baffled?
Thanks guys for that info in the baffle dimns.
My decisions as to where to go next are a little complicated...
Partly it boils down to convenience too. I don't know anyone with a lathe near-by and so I will have to go to a carpenters shop and pay a tooling fee for getting the baffle turned, but I do have some oak that would do it.
I have made the sides from birch ply (which cost a packet) and managed to get those from one 8'x4' sheet. If I went for the front solid wood option, I can order it where I picked up my plywood from. They even offered to put the hole in it for me...The overall cost is about the same as ordering another sheet of ply, just to do the front section (8.75" wide x2) and the rest is waste (for a future project.)
If you have a choice out of a solid ash front or a plywood front with the external baffle, that costs a little extra money, which would you choose???
But it is the sound that really matters. Being my first build I am reluctant to deviate too much from all the great info that has been offered here.
What is the consensus on the solid wood front as a full length baffle? I could make it 1" and route the edges at 45 degress. Would the round baffle be worth the extra...
Martin
Thanks guys for that info in the baffle dimns.
My decisions as to where to go next are a little complicated...
Partly it boils down to convenience too. I don't know anyone with a lathe near-by and so I will have to go to a carpenters shop and pay a tooling fee for getting the baffle turned, but I do have some oak that would do it.
I have made the sides from birch ply (which cost a packet) and managed to get those from one 8'x4' sheet. If I went for the front solid wood option, I can order it where I picked up my plywood from. They even offered to put the hole in it for me...The overall cost is about the same as ordering another sheet of ply, just to do the front section (8.75" wide x2) and the rest is waste (for a future project.)
If you have a choice out of a solid ash front or a plywood front with the external baffle, that costs a little extra money, which would you choose???
But it is the sound that really matters. Being my first build I am reluctant to deviate too much from all the great info that has been offered here.
What is the consensus on the solid wood front as a full length baffle? I could make it 1" and route the edges at 45 degress. Would the round baffle be worth the extra...
Martin
stroop said:
Bubble wrap? Wow! That is an odd stretch, but worth a try. There is a special insulating bubble wrap generally used for metal buildings, it has a foil lining on one side. Very rigid stuff for what it is, I believe I have access to some, and may be a fun test. I was playing with the idea of using an old standard, please do not chastise me, Bose design of having a small mid/high direct deflecting. I was thinking in the top of the horn, mounting a small 2 incher at an angle to bounce off the wall and cieling for a sudo-surround sound. This is similiar to what Godzilla does with his piezos. I am not sure if it would be interrupded by the wound coming out of the horn, and may need to be wired in reverse polarity, if nothing else, could be mounted on the back as there is enough space if you are corner loading. I only say this because I use mine for HT and audio, and my wife loves them too, oddly enough.
We're OT, but I had to chime in about cables. I'm not sure you two are envisioning the same geometry. The cross connects are an attempt to get the impedance as low as possible without the capacitance climbing too high. They are the antithesis of a crossover network for cables. Some people, though, like high impedance desigs. Mapleshade records is an example. Also see the pair spaced in tape that Planet10 pictured in one of his threads.
Paul
Paul
Re: baffled?
Greets!
You're welcome!
Any hardwood suitable for speaker building will be rigid enough that I doubt you could hear any difference between it and void free Baltic Birch or Apple and some marine grades of ply. Any other ply grade may sound different due to voids or poorly plugged voids.
As to which hardwoods are acceptable, the consensus (including TC's input) on the old Fullrangers forum was that any with low moisture retention properties such as white or red oak, white, black or green ash, teak, hard mahogany, french walnut and hard maple. Then for those with machining capability or more patience than folks like me, Lignum Vitae, Kingwood, Cocobolo, Tulipwood, Pau Ferro, Honduras Rosewood, Goncalo Alves, Bubinga, Wenge, and Purpleheart.
The supra baffle is for lowering the baffle step frequency low enough that you don't notice an audible dip between the driver's beaming output and the cab's and room's combined gain BW down low. If required, then how big it is depends on several variables, so making the baffle out of a different material isn't going to change whether or not one is needed.
GM
Martin Prothero said:
Greets!
You're welcome!
Any hardwood suitable for speaker building will be rigid enough that I doubt you could hear any difference between it and void free Baltic Birch or Apple and some marine grades of ply. Any other ply grade may sound different due to voids or poorly plugged voids.
As to which hardwoods are acceptable, the consensus (including TC's input) on the old Fullrangers forum was that any with low moisture retention properties such as white or red oak, white, black or green ash, teak, hard mahogany, french walnut and hard maple. Then for those with machining capability or more patience than folks like me, Lignum Vitae, Kingwood, Cocobolo, Tulipwood, Pau Ferro, Honduras Rosewood, Goncalo Alves, Bubinga, Wenge, and Purpleheart.
The supra baffle is for lowering the baffle step frequency low enough that you don't notice an audible dip between the driver's beaming output and the cab's and room's combined gain BW down low. If required, then how big it is depends on several variables, so making the baffle out of a different material isn't going to change whether or not one is needed.
GM
Drool.
Can you imagine one with maple front, internal and rear baffles with purpleheart sides, built & polished up by the local tame cabinet-maker?
Thanks for the info as ever Greg. BTW -is anyone else having the same problem I am in accessing the old Full Range Forum database? The search page, even for items I know are there, simply doesn't find anything at all.
Can you imagine one with maple front, internal and rear baffles with purpleheart sides, built & polished up by the local tame cabinet-maker?
Thanks for the info as ever Greg. BTW -is anyone else having the same problem I am in accessing the old Full Range Forum database? The search page, even for items I know are there, simply doesn't find anything at all.
Thanks again everyone who contributed to my (rather nice to have) dilemma.
GM - I don't really understand the bit about the reason to have a suprabaffle. Can you explain the bit about equaling out the baffle step ... in a way that I might actually catch up with what you mean. Sorry to ask, but I would rather ask and feel a fool for a minute, than not ask and feel a fool forever!
GM - I don't really understand the bit about the reason to have a suprabaffle. Can you explain the bit about equaling out the baffle step ... in a way that I might actually catch up with what you mean. Sorry to ask, but I would rather ask and feel a fool for a minute, than not ask and feel a fool forever!
I'm not GM, but as he's not at the time of typing on the forum, I'll do my best to explain it as simply as possible & Greg can correct / add to it.
Baffle-step is the point at which bass begins to drop away due to the speaker starting to behave in an omni-directional fashion and less energy is being directed forward. (technically the transitional point between 2 pi hemispherical radiation and 4 pi spherical radiation. Wince.) The loss is typically 6db below this point of baffle-step diffraction. Now, the point at which this occurs depends on the width of the baffle to which the driveunit is attached. The narrower the baffle, the higher in frequency the baffle-step point, the wider, the lower the baffle-step point. The F3 point (-3db ) occurs at approximately 11,600 / baffle width in cm (or if you prefer Imperial, 4566 / baffle width in inches).
So, when you add a suprabaffle, as well as other possible unrelated benefits, you are in fact providing the driver with a wider baffle, and lowering the point at which baffle-step will occur. If the suprabaffle is wide enough, it will lower the baffle-step frequency to a point where the horn will supply the gain lost from baffle-step and flatten the frequency response without needing any other form of correction, from a circuit, active Eq or whatever.
Baffle-step is the point at which bass begins to drop away due to the speaker starting to behave in an omni-directional fashion and less energy is being directed forward. (technically the transitional point between 2 pi hemispherical radiation and 4 pi spherical radiation. Wince.) The loss is typically 6db below this point of baffle-step diffraction. Now, the point at which this occurs depends on the width of the baffle to which the driveunit is attached. The narrower the baffle, the higher in frequency the baffle-step point, the wider, the lower the baffle-step point. The F3 point (-3db ) occurs at approximately 11,600 / baffle width in cm (or if you prefer Imperial, 4566 / baffle width in inches).
So, when you add a suprabaffle, as well as other possible unrelated benefits, you are in fact providing the driver with a wider baffle, and lowering the point at which baffle-step will occur. If the suprabaffle is wide enough, it will lower the baffle-step frequency to a point where the horn will supply the gain lost from baffle-step and flatten the frequency response without needing any other form of correction, from a circuit, active Eq or whatever.
Scott, I think that was a pretty good summary.
Further advantages can be achieved (at the expense of material and most significantly fabrication labour) by extending the thickness of the supra baffle to "wrap around" the sides of the enclosure and profiling with a chamfer or radius edge.
Also, shapes other than round (i.e. square, elliptical, star-burst) are worth experimenting with.
Further advantages can be achieved (at the expense of material and most significantly fabrication labour) by extending the thickness of the supra baffle to "wrap around" the sides of the enclosure and profiling with a chamfer or radius edge.
Also, shapes other than round (i.e. square, elliptical, star-burst) are worth experimenting with.
Ahhhh. I think I get the bafle step concept now! Thanks for that Scott (and Chris).
So to recap, Dmason quoted a measurement of 13" for the 168. If I take a profile (roughly a continuation of the outside edge of the driver cage/surround) and extend that curve out to meet the edges of a 13" Dia circle (1" thick), I am getting pretty close the right dimensions?
All well and good me understanding it - now I,ve got to go into some poor unsuspecting cabinetmaker/joiners workshop and try explaining it to them!
So to recap, Dmason quoted a measurement of 13" for the 168. If I take a profile (roughly a continuation of the outside edge of the driver cage/surround) and extend that curve out to meet the edges of a 13" Dia circle (1" thick), I am getting pretty close the right dimensions?
All well and good me understanding it - now I,ve got to go into some poor unsuspecting cabinetmaker/joiners workshop and try explaining it to them!
Martin Prothero said:All well and good me understanding it - now I,ve got to go into some poor unsuspecting cabinetmaker/joiners workshop and try explaining it to them!
Hi, Martin. I realize the English and we Yanks are two people separated by a common language. Woodworking is one of those places where the jargon is different.
If I were going to explain it to someone here, I'd ask them to face-turn a round blank so that it matches a convex profile like you would draw, starting with the outer dimension of your driver.
Hope that helps.
What's up dude? Long time no hear! I'm still alive, but don't 'kick' so good/much anymore. 
Sadly (IMO), this 'bit of country in the city' is no more. This old 'redneck' is now part of a small minority in a thriving multi-ethnic 'village' where English is rapidly becoming the 3rd language.
GM
PS: FYI we're quoting lyrics from Atlanta Rythm Section's hit 'Doraville'.
Sadly (IMO), this 'bit of country in the city' is no more.
This old 'redneck' is now part of a small minority in a thriving multi-ethnic 'village' where English is rapidly becoming the 3rd language. GM
PS: FYI we're quoting lyrics from Atlanta Rythm Section's hit 'Doraville'.