Ideal constant directivity waveguide makes 6db/octave slope. Put small capacitor to make 1st order (6db) highpass filter somewhere +10kHz to compensate.
Constant directivity waveguide (conical Synergy) is even worse drop. The ES horn is more close to an exponential horn with rising DI. There was a drop of 13 dB in the Runt clone synergy horn between 5k and 10k that is +- 6 dB more than for the ES horn - which is the compensation for constant directivity. I have two of these and they behave the same way, which is really strange and that is why I do not think they are fully OK.
Ladies and gentlemen!
I have adopted the view of the waterfall used by a well known german DIY audio journal Klang + Ton
Visaton DR45N + Visaton HT21
Eighteensound NSD1480N + Eighteensound XT1464 horn
Eighteensound NSD1095N + Eighteensound XT1086 horn
Eighteensound NSD1095N + LMH sTrak 4.5 inch wooden horn
the real interesting thing will be the measurement of the NSD1480N mounted on the LMH sTrak 16 inch wooden horn that will arrive soon to me
I have adopted the view of the waterfall used by a well known german DIY audio journal Klang + Ton
Visaton DR45N + Visaton HT21
Eighteensound NSD1480N + Eighteensound XT1464 horn
Eighteensound NSD1095N + Eighteensound XT1086 horn
Eighteensound NSD1095N + LMH sTrak 4.5 inch wooden horn
the real interesting thing will be the measurement of the NSD1480N mounted on the LMH sTrak 16 inch wooden horn that will arrive soon to me
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Took quick read what actually makes the slope with constant directivity waveguides and actually, nothing
The drivers response comes through as is, it is same to all directions. Rising DI (not constant directivity) waveguide would "boost" the driver response on axis as radiation concentrates there with rising frequency. I guess we tend to compare our system response to datasheet curves. The impression is made as we look the datasheet response and if our own waveguide is more constant directivity the response slopes in comparison. If it is less then it rises (compared to datasheet). If the datasheet curve was made with really beaming device one could have more than 6db/octave slope with constant directivity waveguide? In the end it is the same driver we just look the graphs measured with various waveguides which more or less "boost" the highs. Not considering problems here like diffraction and possible reflections on sudden impedance changes which would add their effect on top.
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The measurement in the datasheet for DE500 is from an exponential horn (ME-45 https://www.bcspeakers.com/en/products/horn/1-0/0/me45), so I would expect it to look similar on the ES horn. The Beyma is measured on TD-565 horn (https://www.beyma.de/fileadmin/seiten/download/pdf/Beyma_professional/TD565.pdf), which is supposedly constant directivity. I am slightly puzzled by this, since the ES is not really constant direrctivity, but is slowly narrowing. Iit would be more similar to this measurement by Joseph Crowe - this is his ES290:
It kind of corresponds to my quick and dirty measurements.
But nevertheless, I can say that my CP755Nd drivers are far superior to the DE500 pair I own - both in FR and quality of sound when equalized.
In theory, the response on an ideal constant directivity horn/waveguide is same shape as the response on a plane wave tube, am I right?
And yes, I must admit, I have a weak spot for the CP755Nd - so much that I will build a pair of smaller hardwood horns for them.
It kind of corresponds to my quick and dirty measurements.
But nevertheless, I can say that my CP755Nd drivers are far superior to the DE500 pair I own - both in FR and quality of sound when equalized.
In theory, the response on an ideal constant directivity horn/waveguide is same shape as the response on a plane wave tube, am I right?
And yes, I must admit, I have a weak spot for the CP755Nd - so much that I will build a pair of smaller hardwood horns for them.
Im very interested in this thread. I use a 12 inch to cover 70 to 800hz (alternating between an AE TD12M and Beyma 12P80ndv2) and a JBL 2451 1,5" with coated Ti dias on top. In other setups Ive tested JBL 2426 and B&C DE250 and although I find the top end on the de250 superior to the 2451 I feel I really like the way the large format driver sound in the lower frequencies. It has more body if you know what i mean and the overall sound and the total experience or presentation gets more natural or realistisc in my setup.
Ive tested pure titanium dias in the 2451 but their breakup is unbearable to me. The coated ones are OK but perhaps 18sounds nsd4015n which is a newer design than the JBL and with the titaniumdioxide dias would be an upgrade? Would be nice if anyone here who have experience with these could chime in
Ive tested pure titanium dias in the 2451 but their breakup is unbearable to me. The coated ones are OK but perhaps 18sounds nsd4015n which is a newer design than the JBL and with the titaniumdioxide dias would be an upgrade? Would be nice if anyone here who have experience with these could chime in
On the other hand, the measurements here (on CD waveguides) show the drop in HF as well - http://www.prodance.cz/protokoly/de500+a9090.pdf and http://www.prodance.cz/protokoly/B&C_DE500+A7570.pdf
For a large(r) format driver this one is interesting: (..and the price is nice.)
http://www.sbaudience.com/index.php/products/compression-drivers/rosso-65cdn-t/
(..nice to see the exit angle in the product sheet; would have liked to have seen something closer to 30 degrees, but 18+ is still pretty good.)
http://www.sbaudience.com/index.php/products/compression-drivers/rosso-65cdn-t/
(..nice to see the exit angle in the product sheet; would have liked to have seen something closer to 30 degrees, but 18+ is still pretty good.)
I really liked the Rosso65CDN-T compression driver (I haven't heard any other CDs though).
Here are the kind of measurements I got in a prototype build with the Rosso65CDN-T attached to a Faital pro LTH 142 horn.
Horizontal polars up to 90 degrees
Vertical polars up to 90degrees
More details about my prototype speaker can be found here:
https://www.diyaudio.com/community/threads/a-3-way-design-study.376620/post-6993828
Thanks
Vineeth
Here are the kind of measurements I got in a prototype build with the Rosso65CDN-T attached to a Faital pro LTH 142 horn.
Horizontal polars up to 90 degrees
Vertical polars up to 90degrees
More details about my prototype speaker can be found here:
https://www.diyaudio.com/community/threads/a-3-way-design-study.376620/post-6993828
Thanks
Vineeth
I just skipped to the end , ask this question then read from the start lol,
Is there any compression drivers 1' that have specs 700-22000
That can play and be happy in the 700 range without giving up the anything in the 18plus range.
I have found the
radian 475pb
celestion cdx1-1745
Bms 4550
Is there any compression drivers 1' that have specs 700-22000
That can play and be happy in the 700 range without giving up the anything in the 18plus range.
I have found the
radian 475pb
celestion cdx1-1745
Bms 4550
It depends more on the horn than the compression driver for the lower-end. Also, the top-end is not likely to have a great deal of dispersion above 12 kHz unless the horn relies on diffraction (with a "pinched" entrance). At 22kHz you probably have less than 10 degrees with a compression driver that can achieve that freq. on most horns. (..though quite narrow at higher freq.s, a Le'Cleach horn should be looked at for both extremes of the freq. response: like the AH-550.)
ex.
https://www.azurahorn.com/azurahorn_horns.html
However, in general only look for drivers with non-metallic surrounds (..usually most surrounds are the same material as the diaphragm). Integrated metal surrounds (Aluminum and Titanium) tend to have greatly increasing non-linear distortion near Fs, but their synthetic alternatives typically aren't quite so aggressive with lower freq. distortion.
A larger diaphragm is also preferred.
If you can handle the correction, this one is titanium with a poly surround and a slightly larger diaphragm (*1.75") in a 1 inch exit:
https://www.parts-express.com/Peerless-DFM-2544R00-08-1-Compression-DFM-Driver-8-Ohm-264-1466?
https://www.parts-express.com/pedoc...-08-compression-dfm-driver-specifications.pdf
(..though who knows when it will be back in stock.)
*note: its also unusually low Mms (..should provide higher subjective clarity as a result of the low mass).
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BMS 4590 coax. I kinda like it more than 4592 coax. Price aside 4590 is flatter.
Celestion axi2050 which is superb. There aren't a lot of options when the crossover point is that low but A-55G is also the best one inch driver for midrange applications that low. Actually it's a great upgrade over Atlas PD-5VH. Reach to it here:
https://critesspeakers.com/k-55-replacement-the-new-a.html
Celestion axi2050 which is superb. There aren't a lot of options when the crossover point is that low but A-55G is also the best one inch driver for midrange applications that low. Actually it's a great upgrade over Atlas PD-5VH. Reach to it here:
https://critesspeakers.com/k-55-replacement-the-new-a.html