supraBaffles & wavelaunch

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#2
I think TC's baffles were originally sized as having a diameter approximately 7in over the driver. Not sure about them now, not having measured one. I doubt it'd be worth getting too worked up over the exact radii applied, so long as it smoothly curves down. There's math in there somewhere, but whatever it is is beyond my limited ablity at this stage.
 
#3
Scottmoose said:
There's math in there somewhere, but whatever it is is beyond my limited ablity at this stage.
Click to expand...

Some match here http://www.t-linespeakers.org/tech/bafflestep/index.html

couple that with Olson's page 23....

olsen-baffleshape-fr.gif


add a dash of cosmetics, and practicality and away you go.

If you want to get fancy Svante's The Edge software is one of the better baffle modelers (unfortunatly only run's on Billy Boxes).

The important thing is that it falls away smoothly and extends back a ways. Getting it large enuff to push bafflestep loss down to where "horn" & room gain start filling stuff in is a bonus.

dave
 
#4
Hi Fab,

I think the extra round baffle could be quite important. It made a significant improvement

when people added one to Ron Clarkes' A166 after he included one on the A126.

He also recommends extending the trailing edge back several inches.

I would like to know what anyone thinks about making it too thick, moving the driver forward.

Any consequences to this?

Thanks, John.
 
#5
Cheers for that Dave! I really should start to use The Edge more than I have in the past.

Regarding the thickness, so long as you're not choking the rear wave, I can't see there being a problem providing it's not getting to be a silly thickness. Up to a couple of inches would be about right IMO. Might shift the centre of gravity of the enclosure forward a bit though!
 
#6
copperhead said:
when people added one to Ron Clarkes' A166 after he included one on the A126.
Click to expand...

In the case of Ron's horns the suprabaffle pushes the baffle step frequency down to where the output from the horn can take over. When he 1st designed the A126 he tried to push the design to where the width of the cabinet was sufficient -- turne out that it meant too much mid coming out of the horn, and too small a CC to let the driver breath, leaving a very boxy, closed in midrange. Enlarging the CC and adding the SupraBaffle transformed the speaker.

And since it is an add-on, it behoves us to shape it in such a manner as to keep difraction effects low and to get a smooth transition from 2 pi radiation to 4 pi with as little ripple as possible.

You can use the thickness of the supraBaffle as a tool to adjust the volume of the CC ... in the case of the BIBs to compensate for the volume taken up by the drivers motor creating a more consistent line xSetcion.

From a cosmetic point of view, you can make the supraBaffle too thick and make the speaker seem to want to fall on its face.

[
sBaffle-close.jpg


Going to the other extreme, the supraBaffle can be pushed to the sides of the cabinet (example on the left -- the one on the right served the purpose of filling a too large hole left by an FR125 but serves the purpose of nicely removing HF edge diffraction and it does look stunning)

treatedFE12xe.jpg


The flush supraBaffle is tricky to make and still not quite right cosmetically... our next ones are going to be proud of the front baffle by a thickness of material and removeable as in this rendering.

frugel-Horn-flat-pak.gif


Another avenue that we have/are exploring is the supraBaffle with built-in waveguide that mounts over the driver.... (as in the attachment -- our mule RonHorn A126s)

All of these ideas can be adapted for use with the BIB.

dave
 

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#7
The last thing you want to consider is the flat circular disk which will have nasty diffraction and high BS ripple.... in the speaker below -- as in DaveCans FE108eS BIBs -- the primary purpose was to make the space deep enuff to accomodate the speaker magnet depth.

dave
 

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#13
Thanks Scott, I forgot GM mentioned about the use of lossy panels for the cabs...yes, worth to try even.
I've looked some TC speakers pictures and the round baffle seems to be larger not less than 3/4 of the drive diameter....

Hi Copperhead,
originally posted by Copperhead
I would like to know what anyone thinks about making it too thick, moving the driver forward. Any consequences to this?
Click to expand...

GM wrote something about this here post 410 If I'm not wrong he underlined, by adding a super baffle, not to exceed 3.4" from driver magnet to the sloping internal baffle.

Hi Dave (sorry, Planet10)
Interesting pictures and graphs. Am I right to deduce that spheric (or hemispheric) and truncated pyramid shapes are the most suitable for a BIB superbaffle?
But I've found really interesting this one:

An externally hosted image should be here but it was not working when we last tested it.


The inside blunted part would easily permit to use a thicker baffle and preserve the right distance from the internal baffle as GM suggested.
Do you think that particular detail will work also with a BIB and how to calculate the right chamfering (it reminds me a round tractrix horn...)?

Thanks.
Ciao.Fab.
 
#14
McFaBs said:
Am I right to deduce that spheric (or hemispheric) and truncated pyramid shapes are the most suitable for a BIB superbaffle?
Click to expand...

It is essential to have some trailing edge -- this can be seen by comparing the sphere to the hemisphere on Olson pg 23... the truncated pyramid is appealing becasue it is easiest to build -- just run the supraBaffle thru the tablesaw... with some judicial use of the rasp you could take off the sharp edges and make a more rounded shape (don't plan on veneering after that thou 🙂)

Do you think that particular detail will work also with a BIB and how to calculate the right chamfering (it reminds me a round tractrix horn...)?
Click to expand...

It is actually a conical (45 degree champher bit) + some use of the rasp....

It isn't really big enuff to do much "horn-wise" more of a restricting dispersion at the lowest frequencies.

Those boxes do perform well... in conjunction with the push-push ApexJr sub i was quite pleased with their HT performance as well.

dave
 
#18
This is an interesting subject insofar as people often
get good results subjectively with circular baffles, in
contrast to the fairly severe diffraction that you can
measure, as seen in this real example:
 

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#19
A very interesting graph that. Not a pretty response. Looking at the curve, the 1.5KHz - 3KHz regions are a little better than the rest, so perhaps we don't hear the worst of it if occurs out of our most sensitive hearing regions? About the only explanation I can think of anyway. Worth looking into though.

BTW -Nelson: do you reckon the Zen V9 would be a good match to these horns? I've run an SoZ with the V6 mods in the past and liked what it did.

Best
Scott
 
#20
planet10 said:


The trailing edge should extend back more, the arrows point to what i mean by trailing edge... an example of a shape that has been optimized to a very high degree is the midrange pod in the big B&Ws.

dave
Click to expand...

Hi Planet10,

Ok, got the concept!

Indeed considering your thought few post ago about round-thin baffle and it's predictable behavier (and the graph NelsonPass posted above), a sphere mounted somehow to the cab should have optimum effects....(but not easy to built!).

Anyway, considering your draw correction the idea should be, more or less, this.... am I on the way?

Thanks.
Ciao.Fab.
 

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