Celestion seems to be doing some neat things with finite element analysis. They have their new "axiperiodic" driver that's supposed to do 300Hz-20khz, but it's unobtanium.
This new driver ISN'T unobtanium: The Celestion CDX-3020. 2" exit and readily available on Amazon ($300) and eBay ($170)
This new driver ISN'T unobtanium: The Celestion CDX-3020. 2" exit and readily available on Amazon ($300) and eBay ($170)
What's so apealing in this curve? For me it simply sucks like hell...🙂
More lofi Pa crap...
More lofi Pa crap...
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What's appealing is the bandwdith.
Celestion seems to be getting good at this FEA thing, and their new drivers are showing it.
For instance, here's the competing driver from B&C. It costs more, it rolls off sooner, it's rolloff is steeper, and it has a noticeable peak in the high frequency.
I am personally not a big fan of 2" compression drivers, but they do seem to be getting better and better.
What's appealing is the bandwdith.
Celestion seems to be getting good at this FEA thing, and their new drivers are showing it.
For instance, here's the competing driver from B&C. It costs more, it rolls off sooner, it's rolloff is steeper, and it has a noticeable peak in the high frequency.
I am personally not a big fan of 2" compression drivers, but they do seem to be getting better and better.
Response Is flatter than the Celestion where It matters. I'd take the B&C.
Any info about the distortion figure on the Celestion? I find the (relatively high) distortion level is a major weak point of many pro compression drivers, and large percentage of pro direct radiators, too!
For example, I recently measured what I thought was a sweet 18" driver only to find that distortion barely beat 1%. If I want that I would just buy Goldwood and be done. You can and should do better, ya know?
Over at PE TT people were recently fawning over a "new" Peerless CD that was not too expensive... "Oooh what a nice flat and extended high end!"... well, until someone measured it. It had 7% distortion! Holy cow pies, Batman. Yeah, sure, that is exactly what I want blasted at my ears at 105+dB/W!
For example, I recently measured what I thought was a sweet 18" driver only to find that distortion barely beat 1%. If I want that I would just buy Goldwood and be done. You can and should do better, ya know?
Over at PE TT people were recently fawning over a "new" Peerless CD that was not too expensive... "Oooh what a nice flat and extended high end!"... well, until someone measured it. It had 7% distortion! Holy cow pies, Batman. Yeah, sure, that is exactly what I want blasted at my ears at 105+dB/W!
Yes, large format beryllium drivers will exceed it's performance
To keep the price under control and increase the bandwidth of a driver, you'll need to obsessively optimize the phase plug, the diaphragm, the interface to the horn, etc
Here's my measurement of the $35 Tymphany
Here's my measurement of a $150 BMS 4552
I just have these two measurements laying around on my hard drive. They're not on the same waveguide so it's an apples and oranges comparison. But for my money, the Tymphany is really difficult to beat at that price point. I have some real B&Cs here, and some Parts Express knock-offs, and the Tymphany offers wider bandwidth.
Not saying it's the "end-all / be-all", but it's really good for the price. It's greatest strength, IMHO, is that it can be crossed over exceptionally low. I made a post about it. If you look at the diaphragm, it appears to be ported(!)
Huh? I've measured it, it doesn't have anything resembling 7% distortion. Maybe a rubbing voice coil in the one they measured?
Everything above about 1500Hz in the plot is from that driver.
Attachments
Although the curve as it is published may not seem appealing try a comparison between a properly implemented design (with this driver) in a real room with a favored dome tweeter. Also not shown are the THD which will typically be lower but more importantly have still lower odd order content. And still yet to be seen is the directivity which will integrate very well with typical family listening rooms all over the world not to mention the woofer too.
In the real world this device has excellent potential.
I am sorry but the only thing that justifies the existence of such devices is P.A. giving ear bleeding SPLs and precise coverage of a given audience, both "benefits" totally useless at home.
For home audio, specific devices more home and ear friendly have been designed, but of course the high spl controled directivity crowd is free to ignore them, no problem.
Also free to mount and enjoy their 2' CD in their cars if it's the next big thing for their listening "pleasure"...
a compression driver on a horn/waveguide similarly sized as the woofer will most often have smoother offaxis response compared to any typical commercial dome tweeter config. even in the low end since they usually are equipped with large woofers also.
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nonsense. a given speaker that sounds ok yet has poor directivity control will virtually always sound better and measure better in-room if modified to perform better on paper.
I am sorry but the only thing that justifies the existence of such devices is P.A. giving ear bleeding SPLs and precise coverage of a given audience, both "benefits" totally useless at home.
For home audio, specific devices more home and ear friendly have been designed, but of course the high spl controled directivity crowd is free to ignore them, no problem.
Also free to mount and enjoy their 2' CD in their cars if it's the next big thing for their listening "pleasure"...
Rubbish.
Compression drivers handle power much better than the typical dome tweeter. Doesn't mean we'll use them that loud, but some of the people here like to have a system that'll produce music at close to live levels.
The controlled dispersion is an excellent feature - you cut down on unwanted reflections, both nearfield and far-field. Imaging improves.
It sounds to me like you've heard a set of cheap PA speakers and decided you know everything there is to know. Have you listened to a well-done system that has a compression driver?
Chris
The problem you have experienced with 12" Tannoy coaxial is primarily a bad XO filter design, not the fact that very high frequencies are rolled off early in comparison to dome tweeters. I don't think Dr.Geddes has implemented foam plugs into his waveguides in vain. That should be investigated further to see what kind of improvements it might have with other types of horns.
Bill, it's your post from which I got the 7% figure:
Impressive new compression driver from Peerless - Techtalk Speaker Building, Audio, Video Discussion Forum
This is a link to your post from PE TT in which you mention the 7% distortion figure. I faintly recall scrolling through the thread quickly and looking for some distortion data. When I came across your post and saw "7% HD2 at 100dBSP" I stopped reading and somehow that number stuck in my brain as the nominal distortion level for the CD.
Now that I have gone back and re-read the post a little more carefully and looked at the plot you attached, I see that the distortion level is just above the 1% mark above about 2kHz.
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I am sorry but the only thing that justifies the existence of such devices is P.A. giving ear bleeding SPLs and precise coverage of a given audience, both "benefits" totally useless at home.
For home audio, specific devices more home and ear friendly have been designed, but of course the high spl controled directivity crowd is free to ignore them, no problem.
Also free to mount and enjoy their 2' CD in their cars if it's the next big thing for their listening "pleasure"...
I have listened to a couple of Zaph's own econowave builds and I can say for certain that they were very good sounding. I think there is a grain of truth to your post but that is not representative of loudspeakers that employ "pro-audio" drivers in general.
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