Good question!
Kinda depends on how different the results are. I had a case were I tried four calculators and 3 were roughly in agreement ie diameter within mm and length within a few cm while the 4th diverged dramatically lengthwise.
Plugging in the different sizes into the different calculators made it clear that extreme precision is not needed. The 3 only varied by a Hertz or two in tuning with negligible results in the predicted curve.
In the end I settled for WinISD as being the most convenient for me to use but the've disappeared from the net recently.
So it is not as bad as I made it sound but it probably pays to try a few and see what they have to say for themselves.
Once you've got the box measure the impedance with various port lengths which should clearly show the actual tuning frequency, you can always mock up some ports with cardboard before you settle for a more permanent material.
Or trust ATC that Billy came up with the optimal compromise for his own driver.
Kinda depends on how different the results are. I had a case were I tried four calculators and 3 were roughly in agreement ie diameter within mm and length within a few cm while the 4th diverged dramatically lengthwise.
Plugging in the different sizes into the different calculators made it clear that extreme precision is not needed. The 3 only varied by a Hertz or two in tuning with negligible results in the predicted curve.
In the end I settled for WinISD as being the most convenient for me to use but the've disappeared from the net recently.
So it is not as bad as I made it sound but it probably pays to try a few and see what they have to say for themselves.
Once you've got the box measure the impedance with various port lengths which should clearly show the actual tuning frequency, you can always mock up some ports with cardboard before you settle for a more permanent material.
Or trust ATC that Billy came up with the optimal compromise for his own driver.
Hi Raul,
thanks for the heads-up.
I decided however to do that clone myself from the scratch.
I have read wary things about Wilmslow regarding their delivering times.
Ans besides that I already got hold of the drivers.
So all I need to worry about by now is the cabinet design and port tuning .. 🙁
Ok peeps, from what I found out the Seas DXT tweeter might NOT be a good match for this project 🙁
Since the ATC mid-range dome has very broad and wide radiation wheras the DXT has more of an even directivity..
Since the ATC mid-range dome has very broad and wide radiation wheras the DXT has more of an even directivity..
You sure about that?
The measurements of the ATC by Troels Gravesen and John Krutke (Zaph) show 3.8-4k to be -6dB at 45 off axis which makes it an ideal match to a waveguided tweeter with 90deg of dispersion.
The measurements of the ATC by Troels Gravesen and John Krutke (Zaph) show 3.8-4k to be -6dB at 45 off axis which makes it an ideal match to a waveguided tweeter with 90deg of dispersion.
it seems I found a pretty darn good tweeter, being very suitable for a ATC SCM100 clone since crossover-point is quite high at 3.5kHz.
http://www.hiquphon.dk/pdf_files/OW3-prospect.pdf
Off-axis response is phenomenal too. find attatched:
http://www.diyaudio.com/forums/attachment.php?attachmentid=665188&stc=1&d=1519768511
http://www.hiquphon.dk/pdf_files/OW3-prospect.pdf
Off-axis response is phenomenal too. find attatched:
http://www.diyaudio.com/forums/attachment.php?attachmentid=665188&stc=1&d=1519768511
Ideally going up in frequency you want a constant directivity, failing that a gently narrowing one. What is really to be avoided is dispersion that mushrooms out as happens with most cone'n'dome 2ways.
ATCs refusal to use waveguides is the one obvious place were improvement over the original is possible.
With that in mind this is not a tweeter I'd be happy to partner with the ATC mid which has 90deg of dispersion at 3.5-4k.
From a dispersion point of view the SEAS DXT is a much better match.
ATCs refusal to use waveguides is the one obvious place were improvement over the original is possible.
With that in mind this is not a tweeter I'd be happy to partner with the ATC mid which has 90deg of dispersion at 3.5-4k.
From a dispersion point of view the SEAS DXT is a much better match.
hm, the thing I really don't like about the DXT is its roll-off from 5k upwards.
that's something which I would want to compensate and hence lose sensitivity.
what's your evaluation for a ScanSpeak d3004-660000?
http://www.scan-speak.dk/datasheet/pdf/d3004-660000.pdf
that's something which I would want to compensate and hence lose sensitivity.
what's your evaluation for a ScanSpeak d3004-660000?
http://www.scan-speak.dk/datasheet/pdf/d3004-660000.pdf
A waveguide will increase output up to a certain frequency by restricting dispersion.
This usually can be fixed with a single capacitor of the right value or via dsp/eq.
It is why waveguided tweeters have lower distortion than those without.
My own reasons why I would not use the DXT is the huge breakup peak just above 20k.
I know I can't consciously hear it but I do find tweeters with those peaks (ie most metal domes) get annoying after a while.
Personally and disregarding price I would pick the Scanspeak R2604/833000 or Peerless/Vifa XT25BG60 with waveguide and the necessary compensation.
They are very robust, have great extension without breakup, decent sensitivity and in a waveguide ridiculously low distortion.
Note that I am talking about the double magnet version of the XT25.
In this case the twin magnet is not used for shielding but to increase sensitivity and reduce distortion.
Its surprisingly low price seems to put people off though, seemingly for no other reason than that there are tweeters around costing 4 or 5x as much without bringing anything extra to the table.
This german site has some info and measurements of waveguided tweeters including the lesser, single magnet XT25:Heissmann Acoustics – Lautsprecherentwicklungen Magazin mit Tests und Berichten rund um das Thema Lautsprecher-Selbstbau
There are measurements and other info on this very site though.
This usually can be fixed with a single capacitor of the right value or via dsp/eq.
It is why waveguided tweeters have lower distortion than those without.
My own reasons why I would not use the DXT is the huge breakup peak just above 20k.
I know I can't consciously hear it but I do find tweeters with those peaks (ie most metal domes) get annoying after a while.
Personally and disregarding price I would pick the Scanspeak R2604/833000 or Peerless/Vifa XT25BG60 with waveguide and the necessary compensation.
They are very robust, have great extension without breakup, decent sensitivity and in a waveguide ridiculously low distortion.
Note that I am talking about the double magnet version of the XT25.
In this case the twin magnet is not used for shielding but to increase sensitivity and reduce distortion.
Its surprisingly low price seems to put people off though, seemingly for no other reason than that there are tweeters around costing 4 or 5x as much without bringing anything extra to the table.
This german site has some info and measurements of waveguided tweeters including the lesser, single magnet XT25:Heissmann Acoustics – Lautsprecherentwicklungen Magazin mit Tests und Berichten rund um das Thema Lautsprecher-Selbstbau
There are measurements and other info on this very site though.
choosing has never been harder haha.. I really don't like ring-radiators.
anyways, it's my turn now to decide.
think its either between a seas t25cf001 (which ATC originally used) or this ScanSpeak D3004/660000 which has nice specs.
but thanks guys and darwin for all your input re: tweeter.
any more input regarding port tuning and cabinet damping is always welcome.
🙂
anyways, it's my turn now to decide.
think its either between a seas t25cf001 (which ATC originally used) or this ScanSpeak D3004/660000 which has nice specs.
but thanks guys and darwin for all your input re: tweeter.
any more input regarding port tuning and cabinet damping is always welcome.
🙂
http://www.bliesma.de/product.html
There you go. Can't really find anything else comparable in a direct radiating dome.
There you go. Can't really find anything else comparable in a direct radiating dome.
One of the takeaways for DIYers is that they have removed the ferrofluid in this design + wave guide
Regarding the dispersion, in the specs they call it 80 degrees coherent . Im wondering what it means from an engineering perspective
For everybody interested: I got two sources confirmed that ATC tunes its ports on the SCM100 to 30Hz .. finally some insight
WTF.. I have overseen this first and just stumbled upon it and was grasping.
Couldnt find much info about this tweeter and company but the factsheet looks to good to be true.. 😱
If all that's true, maybe the best tweeter in the market?!
Would it be of any downsides -sonically speaking- pairing a soft-dome midrange unit with a aluminium tweeter?
The DXT would also be made of aluminium alloy
I have one on the way. HiFi Compass and Troels confirmed the measurements independently. Hoping for good results. They go into full production in June but have a few pairs available at the moment.
I think you would be fine pairing different materials as long there are no nasty breakups in the pass bands.
I think you would be fine pairing different materials as long there are no nasty breakups in the pass bands.
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sorry I have to get back to this topic regarding the cabinet lining.
I decided to line the cabinet with egg crate foam.
I am just hesistant about its thickness.. 8cm is reasonable or even too thick?