Megaton
Thanks for the reply. Yes, it's confused me as the whole range is on their site.
I had already arranged for a company in the UK to bead blast and anodize them... only to find Prodance and their UK distributor knew nothing about them...
You would think they would like to sell the products they list? Their site has no information regarding international shipping either.
Completely at a loss...I've sent prodance a screen shot of their own web page to see if I can get any closer to actually being able to buy stuff off them!
Thanks for the reply. Yes, it's confused me as the whole range is on their site.
I had already arranged for a company in the UK to bead blast and anodize them... only to find Prodance and their UK distributor knew nothing about them...
You would think they would like to sell the products they list? Their site has no information regarding international shipping either.
Completely at a loss...I've sent prodance a screen shot of their own web page to see if I can get any closer to actually being able to buy stuff off them!
There might be three reasons:
1. CZ was hit pretty hard by Corona, maybe they have problems because of this.
2. Their website says they moved recently, maybe they're still getting back on track after moving.
3. Maybe they don't speak English very well, and you're better of with a machine translated email.
Or maybe all of the above.
1. CZ was hit pretty hard by Corona, maybe they have problems because of this.
2. Their website says they moved recently, maybe they're still getting back on track after moving.
3. Maybe they don't speak English very well, and you're better of with a machine translated email.
Or maybe all of the above.
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Which horn?
I think that most of them are available elsewhere, e.g. Parts Express, or ZXPC (seller on ebay) have equivalents that are pretty cheap.
The c1250 details are: 2", 460x288x247mm.
Three JBL models listed here have similar dimensions and a similar diffraction slot.
JBL Drivers & Components
One of them is the JBL 2385.
P.AUDIO makes the PH-4528, which is a copy of the JBL 2385 you can get for about 1/4 of the price.
Selenium also:
Selenium HM4750-SLF 2" Bi-Radial Horn 90x40 4-Bolt
I'm sure there are many other similar horns.
"they need to be machined to accept a ribbon tweeter mounting plate"
Will you be cutting the throat off, to mount the ribbon in the diffraction slot?
I'm not sure what your project is, but it may be simpler to just DIY the shape you need.
As an example, here is me modifying a cheap ebay horn to give it a much bigger mouth + roundover (post 20).
paper cone open frame driver for front horn
No skill or expensive stuff used, just lots of wood scraps and cheap filler.
Three JBL models listed here have similar dimensions and a similar diffraction slot.
JBL Drivers & Components
One of them is the JBL 2385.
P.AUDIO makes the PH-4528, which is a copy of the JBL 2385 you can get for about 1/4 of the price.
Selenium also:
Selenium HM4750-SLF 2" Bi-Radial Horn 90x40 4-Bolt
I'm sure there are many other similar horns.
"they need to be machined to accept a ribbon tweeter mounting plate"
Will you be cutting the throat off, to mount the ribbon in the diffraction slot?
I'm not sure what your project is, but it may be simpler to just DIY the shape you need.
As an example, here is me modifying a cheap ebay horn to give it a much bigger mouth + roundover (post 20).
paper cone open frame driver for front horn
No skill or expensive stuff used, just lots of wood scraps and cheap filler.
Yes, frustrating. And even showing in "stock". But no way of actually buying them. I've sent them a screen shot of their own e shop order form...horns in basket, address details filled in, except the "State/country" entry which apparently is either Czech Rep or Slovakia...no other options permitted, like UK or any other country come to that!
And no information anyway about international shipping.
One e mail from them said to buy from the e shop, another didn't even think they distribute them, despite the whole range still showing on their site. I've contacted them numerous times and just not getting answers.
I'm honestly losing the will to live
I would expect these issues in the UK, but not from Cz!!
And no information anyway about international shipping.
One e mail from them said to buy from the e shop, another didn't even think they distribute them, despite the whole range still showing on their site. I've contacted them numerous times and just not getting answers.
I'm honestly losing the will to live
I would expect these issues in the UK, but not from Cz!!Sorry Hollowboy...didn't have my glasses!! Yes, machining off the throat and using the slot to match the ribbon dimensions. I have a company in the UK ready to cut the horn and manufacture a dedicated ali mounting plate. The whole assembly will be bead blasted and anodised...expensive, yes...but a high end product with commensurate quality finish...I hope!!
Yes, or from "composite" materials (fibreglass).
"I have a company in the UK ready to cut the horn and manufacture a dedicated ali mounting plate."
They (or a similar company) could do that with a fibreglass horn: build a temporary form around the cut-down throat, and pour resin into the space between the horn throat and the formwork.
The (new) throat will then be encased in a solid block of resin - strong enough to use as a mounting plate.
This guy sells horn ribbons, and also CAD plans for them (so you can get them cut loacally). His website says he can modify the horn to suit your driver.
Front Horns – Joseph Crowe
Not sure of the price (to make modifications to plans), or how much the cutting would cost you.
Note that it doesn't have to be a specialty 3D place that does your cutting - some other businesses, like plywood suppliers and cabinet makers, have the same equipment.
---
Alternatively: a few companies sell horn+ribbon combos.
Beyma TPL-150H pleated diaphragm horn tweeter - Beyma TPL-150H - Beyma TPL-150H high frequency horn tweeter. Beyma TPL-150H high frequency tweeter is available here at US Speaker. Beyma TPL-150H speaker components.
Beston RT004A-D Horn Loaded Ribbon Tweeter
Maybe there is an off-the-shelf replacement part that would work?
Front Horns – Joseph Crowe
Not sure of the price (to make modifications to plans), or how much the cutting would cost you.
Note that it doesn't have to be a specialty 3D place that does your cutting - some other businesses, like plywood suppliers and cabinet makers, have the same equipment.
---
Alternatively: a few companies sell horn+ribbon combos.
Beyma TPL-150H pleated diaphragm horn tweeter - Beyma TPL-150H - Beyma TPL-150H high frequency horn tweeter. Beyma TPL-150H high frequency tweeter is available here at US Speaker. Beyma TPL-150H speaker components.
Beston RT004A-D Horn Loaded Ribbon Tweeter
Maybe there is an off-the-shelf replacement part that would work?
The Beston example is the same.
"Since the aspect ratio of the RT002A’s aperture is pretty extreme (as are many ribbon transducers), there is substantial directivity in the vertical plane"
Test Bench: Beston Technology RT002A Ribbon Tweeter | audioXpress
Don't all tall planar drivers have naff vertical dispersion for exactly this reason?
As far as I know, you need physical mods to overcome this, e.g. run 3 ribbons as a MTM, or do (effectively) the same thing by shading the top and bottom of the ribbon with foam:
Raal 140-15 Foam Deflector Pad
"Since the aspect ratio of the RT002A’s aperture is pretty extreme (as are many ribbon transducers), there is substantial directivity in the vertical plane"
Test Bench: Beston Technology RT002A Ribbon Tweeter | audioXpress
Don't all tall planar drivers have naff vertical dispersion for exactly this reason?
As far as I know, you need physical mods to overcome this, e.g. run 3 ribbons as a MTM, or do (effectively) the same thing by shading the top and bottom of the ribbon with foam:
Raal 140-15 Foam Deflector Pad
Hmm, the few ribbons I've been around have 180 deg bends vertically, so if 1" wide, then it only controls down to: 10^6/[1*180] = ~5,556 Hz/F6 no matter how long it is whereas the WG loaded RT002A will go much lower.
Horizontally though, if 60" long, then even if 180 deg will now control down to ~93 Hz/F6.
Horizontally though, if 60" long, then even if 180 deg will now control down to ~93 Hz/F6.
Interesting stuff. Yes, ribbons have relatively poor vertical dispersion face mounted due to their height..one of the reasons I am tempted with the idea of a wave guide of decent size. The Beston has a shallow waveguide to load it for a bit more efficiency...and protection.
The model for mine is much closer to the tractrix design of the Decca London horns, many of which I have owned in the past. Even had a pair of the Kelly diffraction ribbons stuck between stacked Quads back in the 70's....
The London horn is now highly sort after (wish I had kept them..I bought 6 complete Decca London speakers in the 80's as a job lot..and sold them for £50 a pair (what I paid for them, when desperate!!)..
It would appear a "2380" style horn if cut where the slot starts would match a 2" ribbon around 12mm in width. My hope is that the flare will provide decent loading (increased efficiency) and improved dispersion over a "stand alone" ribbon.
My choice of ribbon has a rear chamber similar to the Decca London Stanley Kelly design...
Which is why it is frustrating having got to this stage, including setting up a costed deal with an aluminium machining company, I now can't get any sense out of Prodance. I am now looking at the B&C me75 ali jbl copy, but the Megaton starts with a 120 x 50 flare as opposed to the more traditional 90 x 40....
The model for mine is much closer to the tractrix design of the Decca London horns, many of which I have owned in the past. Even had a pair of the Kelly diffraction ribbons stuck between stacked Quads back in the 70's....
The London horn is now highly sort after (wish I had kept them..I bought 6 complete Decca London speakers in the 80's as a job lot..and sold them for £50 a pair (what I paid for them, when desperate!!)..
It would appear a "2380" style horn if cut where the slot starts would match a 2" ribbon around 12mm in width. My hope is that the flare will provide decent loading (increased efficiency) and improved dispersion over a "stand alone" ribbon.
My choice of ribbon has a rear chamber similar to the Decca London Stanley Kelly design...
Which is why it is frustrating having got to this stage, including setting up a costed deal with an aluminium machining company, I now can't get any sense out of Prodance. I am now looking at the B&C me75 ali jbl copy, but the Megaton starts with a 120 x 50 flare as opposed to the more traditional 90 x 40....
Interesting responses but none relevant to the design I have in mind which is neither a long planar ribbon nor a face mounted Beston type with a short loading wave guide.
My design is inspired by the superb Decca London horn, many of which I have owned in the past..and sold for silly cheap money back in the day!! I also had the Kelly diffraction ribbon classically placed between stacked Quads.
The London was a Tractrix and I am working with bi-radial of course on my design, but the slot is no longer a diffraction slot but instead matches the dimensions of the ribbon, and is therefore now a throat. The ribbon has a back chamber as did the Londons.
Of course back in the 70's Mr Keele had not designed the bi-radial flare, so performance could be interesting. I found these specs and polars for the London on the web and the horizontal dispersion is excellent. Bi radial might even be better and performance will have to be empirically measured as no other examples of this design exist. I am expecting vertical dispersion to follow suite and certainly be no "worse" than the London, and hopefully better.
Sorry for two similar responses...thought the last one done on the phone hadn't loaded!
My design is inspired by the superb Decca London horn, many of which I have owned in the past..and sold for silly cheap money back in the day!! I also had the Kelly diffraction ribbon classically placed between stacked Quads.
The London was a Tractrix and I am working with bi-radial of course on my design, but the slot is no longer a diffraction slot but instead matches the dimensions of the ribbon, and is therefore now a throat. The ribbon has a back chamber as did the Londons.
Of course back in the 70's Mr Keele had not designed the bi-radial flare, so performance could be interesting. I found these specs and polars for the London on the web and the horizontal dispersion is excellent. Bi radial might even be better and performance will have to be empirically measured as no other examples of this design exist. I am expecting vertical dispersion to follow suite and certainly be no "worse" than the London, and hopefully better.
Sorry for two similar responses...thought the last one done on the phone hadn't loaded!
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