Greets!
Any sharp edge is going to cause ripples in the response over some BW and since the purpose of the supra baffle is to reflect said BW, the question becomes, will it be in our acute hearing BW? For typical 'FR' drivers, the answer is yes, so an aerodynamically shaped one is desirable, though IMO even a crude one is better than nothing assuming it's large enough to blend the driver's radiation with the BLH's, ~alleviating the typical (lower) mids broad band dip.
Any round over is better than nothing, but it really needs to be quite large and shaped just so to be truly effective, requiring a very thick supra baffle. Anyway, a round baffle has an infinite number of identical standing waves, so it will cause a high Q notch in the response and peaks comb filtering with the driver's radiation. OTOH, an ellipse will have a very high number of slightly different frequency standing waves that will cause a low Q version, so potentially the worse of the two.
GM
Any sharp edge is going to cause ripples in the response over some BW and since the purpose of the supra baffle is to reflect said BW, the question becomes, will it be in our acute hearing BW? For typical 'FR' drivers, the answer is yes, so an aerodynamically shaped one is desirable, though IMO even a crude one is better than nothing assuming it's large enough to blend the driver's radiation with the BLH's, ~alleviating the typical (lower) mids broad band dip.
Any round over is better than nothing, but it really needs to be quite large and shaped just so to be truly effective, requiring a very thick supra baffle. Anyway, a round baffle has an infinite number of identical standing waves, so it will cause a high Q notch in the response and peaks comb filtering with the driver's radiation. OTOH, an ellipse will have a very high number of slightly different frequency standing waves that will cause a low Q version, so potentially the worse of the two.
GM
Drawing the ellipse is EZ.
Finding the center is not.
I just was at the local Menards big box lumber place and they
have curved edge 'rounds' of 12 in diameter for $5.
The ellipse plaques from the Hobby Lobby are also molded
on the sides.
After using the suprabaffle for a while and listening, I'm thinking
it's just lipstick. I'm not hearing much of a difference on the MLTL
where it's installed.
I originally had the supra on the BIB and couldn't stand it.
I figured that was because of the hole size that sound had to travel through 2 thicknesses. So on the modified MLTL, I enlarged the
cutout on the box to 5 in and chamfered the edge of the 4 in supra
hole at the rear to give breathing room for my FE127e.
Word: make some extra front baffles for experimentation.
Finding the center is not.
I just was at the local Menards big box lumber place and they
have curved edge 'rounds' of 12 in diameter for $5.
The ellipse plaques from the Hobby Lobby are also molded
on the sides.
After using the suprabaffle for a while and listening, I'm thinking
it's just lipstick. I'm not hearing much of a difference on the MLTL
where it's installed.
I originally had the supra on the BIB and couldn't stand it.
I figured that was because of the hole size that sound had to travel through 2 thicknesses. So on the modified MLTL, I enlarged the
cutout on the box to 5 in and chamfered the edge of the 4 in supra
hole at the rear to give breathing room for my FE127e.
Word: make some extra front baffles for experimentation.
FF165K size
Does anyone have the latest/optimal sizes for a FF165K BIB ?
I'd get them from Godzilla's site, but that's been down a bit and I just can't wait to get going.
A search in this thread was not conclusive : I guess it's somewhere around :
L : 69"
Zd : 30" (so from top)
Sm : 88.125 "^2
Please confirm or correct if need be.
There was also a version with an extended length (168"). Any preference for either one ?
Thanks,
Gert
Does anyone have the latest/optimal sizes for a FF165K BIB ?
I'd get them from Godzilla's site, but that's been down a bit and I just can't wait to get going.
A search in this thread was not conclusive : I guess it's somewhere around :
L : 69"
Zd : 30" (so from top)
Sm : 88.125 "^2
Please confirm or correct if need be.
There was also a version with an extended length (168"). Any preference for either one ?
Thanks,
Gert
The 165k in a BIB is awesome! I don’t recall one with a longer line length but I may have missed it. I will post it on ZillaSpeak if it pops up. My 165k BIB has a shorter line and its still great. Not optimal but it works for me.
http://www.zillaspeak.com/bib-godzillabib.asp
I can tell more can be wrought from this simple looking driver.
Not to put a damper on anyones enthusiasm to build a 165k BIB but it does have shortcomings – just like any other speaker. Living and listening to it for a few months Ive noticed that cymbal crashes are not as accurate as they could be. I will attempt to dial in the super tweeter (rear firing) to make things better. Treble is detailed but when a cymbal crashes and is left to fade away it sounds like its fading in and out before it stops completely.
Sort of like CRASH – in out in out in out in out… and then its gone.
I noticed this after moving the BIBs to another room and hooking them to my tube amp/preamp. It could very well be the CD player or the quality of the recordings… or the super tweeter… or the room. I have a feeling its a combination of all of these things. Maybe the old radio shack pod super tweeter just isn’t up to the task? Maybe it needs to face forward? Otherwise, mate your 165k with a quality super tweeter for best results. Perhaps thats why Madisound recommends such an expensive tweeter for the BK16 build? Maybe a ribbon?
Still an amazing speaker! Just nit picking.
Sorry ZillaSpeak.com was down. Its finally back. My IT guy says we may need to come up with a better plan for hosting all our websites in the future. If the site goes down just email me for the dims. I have access to the website even when its down.
Godzilla
http://www.zillaspeak.com/bib-godzillabib.asp
I can tell more can be wrought from this simple looking driver.
Not to put a damper on anyones enthusiasm to build a 165k BIB but it does have shortcomings – just like any other speaker. Living and listening to it for a few months Ive noticed that cymbal crashes are not as accurate as they could be. I will attempt to dial in the super tweeter (rear firing) to make things better. Treble is detailed but when a cymbal crashes and is left to fade away it sounds like its fading in and out before it stops completely.
Sort of like CRASH – in out in out in out in out… and then its gone.
I noticed this after moving the BIBs to another room and hooking them to my tube amp/preamp. It could very well be the CD player or the quality of the recordings… or the super tweeter… or the room. I have a feeling its a combination of all of these things. Maybe the old radio shack pod super tweeter just isn’t up to the task? Maybe it needs to face forward? Otherwise, mate your 165k with a quality super tweeter for best results. Perhaps thats why Madisound recommends such an expensive tweeter for the BK16 build? Maybe a ribbon?
Still an amazing speaker! Just nit picking.
Sorry ZillaSpeak.com was down. Its finally back. My IT guy says we may need to come up with a better plan for hosting all our websites in the future. If the site goes down just email me for the dims. I have access to the website even when its down.
Godzilla
http://www.zillaspeak.com/bib-fostex.asp
Thanks GM. I added the info along with the chart. It does go deeper than the shorter BIB! Overall dims will be about 15 inches taller (approx 85 inches opposed to approx 70 inches). I say approx since many seem to come up with an interesting bottom treatment for their BIBs that changes the overall dims.
http://www.zillaspeak.com/bib-pics.asp
Personally, i like tall and slim. Especially when its functional and attractive!
Thanks GM. I added the info along with the chart. It does go deeper than the shorter BIB! Overall dims will be about 15 inches taller (approx 85 inches opposed to approx 70 inches). I say approx since many seem to come up with an interesting bottom treatment for their BIBs that changes the overall dims.
http://www.zillaspeak.com/bib-pics.asp
Personally, i like tall and slim. Especially when its functional and attractive!
resident said:
Greets!
Can be, I mean even if Harry Olson hadn't proved it, Mother Nature has rather dramatically proven that a sphere is the ideal by making the planets nominally round.
Once we move away from the ideal we have to determine the baffle's round over based on a specific LF cut-off frequency. Long story short, ideally its radius needs to be = radius of the LF frequency chosen, so if 300 Hz, then ~13560"/300/2pi = 7.4" and roll over past ~213 deg. IIRC.
Not real practical for most woodworkers, but there's a work-around directivity formula that by increasing the baffle's flat area to a low enough frequency, the transition will have low distortion: 10^16/(300 Hz*180 deg) = ~18.5" diameter. Now the baffle need only be thick enough to be rigid, well damped with just a cosmetic rounding of the edges, though of course it would look strange on an otherwise narrow baffle.
The supra baffle size is dependent on the cut-off required based on the speaker's in-room performance and the driver's size has no bearing on it.
GM
To tweet or not to tweet
That ofcourse moots the 168ez or 165kk question somewhat (insofar as that is an acceptable use of the verb, but you know what I mean. Grasping the subtleties of a foreign language is not so easy).
The 168ez is definitely usable without a supertweeter. If I add the cost of a good tweeter (let alone a ribbon) to the cost of the 165kk, the 168 might be the more economical choice in the end.
Maybe dmason can give some comment. He has practical experience with both drivers, hasn't he ?
Or maybe Scott could give his impression on the performance of the upper octaves on the 165kk, albeit without a direct comparison then.
Gert
That ofcourse moots the 168ez or 165kk question somewhat (insofar as that is an acceptable use of the verb, but you know what I mean. Grasping the subtleties of a foreign language is not so easy).
The 168ez is definitely usable without a supertweeter. If I add the cost of a good tweeter (let alone a ribbon) to the cost of the 165kk, the 168 might be the more economical choice in the end.
Maybe dmason can give some comment. He has practical experience with both drivers, hasn't he ?
Or maybe Scott could give his impression on the performance of the upper octaves on the 165kk, albeit without a direct comparison then.
Gert
Hey Zilla, did you ever get the dimensions totally optimised for the FE168 Sigma unit (original with whizzer cone and holed dustcap, not the current production crinkle E Sigma unit?
Mine are still sitting on open baffles and awaiting new cabs so if you found a set of optimised dimensions that work better than the BIB you have listed then I'm all ears.
Drew
Mine are still sitting on open baffles and awaiting new cabs so if you found a set of optimised dimensions that work better than the BIB you have listed then I'm all ears.
Drew
168ez
well, the two sets of drivers are really a bit different.
some might like the tone of the 165k better (it is very flat, and the kenaf cone sounds really nice), but it certainly needs a tweeter, and those are quite difficult to setup properly.
I like the 168ez alot. they take immense breaking time, but when the things are singing, the are very special indeed. the have awesome treble (after that final shout goes away).
they are as dynamic as an 8 inch, but image better, have enough treble to go solo, etc.
they are a very musical speaker.
the 208 is even more dynamic than that, (by a large margin) and they are true high efficiency to boot, but need a nice tweeter setup.
well, later.
Clark
well, the two sets of drivers are really a bit different.
some might like the tone of the 165k better (it is very flat, and the kenaf cone sounds really nice), but it certainly needs a tweeter, and those are quite difficult to setup properly.
I like the 168ez alot. they take immense breaking time, but when the things are singing, the are very special indeed. the have awesome treble (after that final shout goes away).
they are as dynamic as an 8 inch, but image better, have enough treble to go solo, etc.
they are a very musical speaker.
the 208 is even more dynamic than that, (by a large margin) and they are true high efficiency to boot, but need a nice tweeter setup.
well, later.
Clark
rcdaniel said:
Likely and perhaps it only need just 1 person at Madisound who started the trend...
It would be nice to be able to reliably type characters like ? (sigma), ? (ohms/omega), ° (degrees), µ (mu), ß (beta), ? (root) and have them reliably show up across all platforms.
dave
Note: or even between the edit window & the actual post (the BBS sw looks to have changed some characters that looked OK in compose window into question marks)
>>> Hey Zilla, did you ever get the dimensions totally optimised for the FE168 Sigma unit (original with whizzer cone and holed dustcap...
Nope. I dont think i ever totally optimised any design ever. Scott provided these dims:
BIB for FE168S - old style with wizzer
L = (Line length) 113"
Zdriver = Driver 22.5" down from sealed end of cabinet
Sm = 74.25"^2
If there is another set of dims for the older 168S deep within this thread can someone locate it and i will add it to zillaspeak.
Personally, i like the sound best so far with the older 168S in the 48L ported box.
http://melhuish.org/audio/DIYBX19.html
Overall, i think i prefer the sound of the 165k over the older 168S in the BIB because there is always a slight shout or sheen with the 168S. The 168S goes louder with less distress tho. Otherwise they are both amazing drivers regardless of cost.
Nope. I dont think i ever totally optimised any design ever. Scott provided these dims:
BIB for FE168S - old style with wizzer
L = (Line length) 113"
Zdriver = Driver 22.5" down from sealed end of cabinet
Sm = 74.25"^2
If there is another set of dims for the older 168S deep within this thread can someone locate it and i will add it to zillaspeak.
Personally, i like the sound best so far with the older 168S in the 48L ported box.
http://melhuish.org/audio/DIYBX19.html
Overall, i think i prefer the sound of the 165k over the older 168S in the BIB because there is always a slight shout or sheen with the 168S. The 168S goes louder with less distress tho. Otherwise they are both amazing drivers regardless of cost.
>>> Unfortunately it's a case of "run what you brung" and the 168Sigma is what I've got.
Not unfortunate at all! Its an amazing driver overall! Could sound scary real at times. Live with it a while then try listening to some expensive multiways. You will be amazed how mechanical they sound.
Enjoy!
Not unfortunate at all! Its an amazing driver overall! Could sound scary real at times. Live with it a while then try listening to some expensive multiways. You will be amazed how mechanical they sound.
Enjoy!