otto88 said:
Hi All. I'm pondering a P. Audio 18CX38 myself. Do you have any other measured T/S parameters to share besides the Qes?
Thanks
Portlandmike
Opened the xls file and it looks like the Empire State building to me!
Not real sure about that as a baffle, but it looks cool. 😎
Portland Mike - PM me if you want. I have measurements.
I'm also a Mike and in Portland, now. (ex-Maui)
Not real sure about that as a baffle, but it looks cool. 😎
Portland Mike - PM me if you want. I have measurements.
I'm also a Mike and in Portland, now. (ex-Maui)
Anyone have any freq response measurements they'd be willing to share of the 18CX38?
edit:
Also, I'm curious about where to get them in the US, besides one website I've always known (common sense audio). A few other sites I know of that sell P.Audio coaxials don't seem to list the 18CX38.
edit:
Also, I'm curious about where to get them in the US, besides one website I've always known (common sense audio). A few other sites I know of that sell P.Audio coaxials don't seem to list the 18CX38.
Hey!
I've been thinking about the 15CX38 and the 18CX38 for quite some time now, and I am having a hard time deciding which to choose.
I was browsing about for abovementioned, *again*. When i stumbled across these:
http://www.bluearan.co.uk/index.php?id=PAUSN15C&browsemode=category
Wtf?! The power rating is rather low compared to the **CX38, but that doesnt really scare me, but Neo magnets? I would like to see the measurements of this thing! Anyone know about it?
I've been thinking about the 15CX38 and the 18CX38 for quite some time now, and I am having a hard time deciding which to choose.
I was browsing about for abovementioned, *again*. When i stumbled across these:
http://www.bluearan.co.uk/index.php?id=PAUSN15C&browsemode=category
Wtf?! The power rating is rather low compared to the **CX38, but that doesnt really scare me, but Neo magnets? I would like to see the measurements of this thing! Anyone know about it?
Hi there,
I read through this thread and didn't find many discussions on the effects of vibrating waveguide - I mean the cone.
Shape (profile) aside, how significant does that vibrating horn wall affect the mid-high frequecies? I don't remember seeing any measurements.
Any comments?
I read through this thread and didn't find many discussions on the effects of vibrating waveguide - I mean the cone.
Shape (profile) aside, how significant does that vibrating horn wall affect the mid-high frequecies? I don't remember seeing any measurements.
Any comments?
I thought those P.Audio neos were going away. One of the US resellers had them on sale, but they all went fast. Maybe they are still current?
As for the vibrating waveguide - IMO it should be awful - but it does not seem to be. Certainly no worse than a full range cone. I've heard Doppler effects off a full range cone, but don't remember hearing them from a big Coax.
As for the vibrating waveguide - IMO it should be awful - but it does not seem to be. Certainly no worse than a full range cone. I've heard Doppler effects off a full range cone, but don't remember hearing them from a big Coax.
Yeah, I think they are faded out or something, hard to find them in stock.
Anyway, what about the 15CX38 and the 18CX38?
I am having trouble deciding. They probably sound a little bit different, anyone heard both? Is the 18" fast enough to really nail the drum sounds? What about midrange? Any real-life comparisons at all?
Anyway, what about the 15CX38 and the 18CX38?
I am having trouble deciding. They probably sound a little bit different, anyone heard both? Is the 18" fast enough to really nail the drum sounds? What about midrange? Any real-life comparisons at all?
I can't compare the 18 to the 15, as I've never heard the 15".
But your question - "18" fast enough to really nail the drum sounds?" Ha! Yeah. Like little else I've ever heard. Speed AND weight. And that both on open baffle and ported box. Sounds like real, live drums.
The 18 has the advantage of the big "waveguide" for the horn. That means you can cross it pretty low - below 1KHz, easy.
But your question - "18" fast enough to really nail the drum sounds?" Ha! Yeah. Like little else I've ever heard. Speed AND weight. And that both on open baffle and ported box. Sounds like real, live drums.
The 18 has the advantage of the big "waveguide" for the horn. That means you can cross it pretty low - below 1KHz, easy.
if woofer's high frequencies are filtered out, moving cone itself should not interfere with compression driver's high frequencies.
those frequencies bounce the same way from stationary or slow moving object (woofer cone), no difference there.
I assume so, maybe I'm incorrect.
those frequencies bounce the same way from stationary or slow moving object (woofer cone), no difference there.
I assume so, maybe I'm incorrect.
So are you saying they work better with an active crossover?
I am thinking maybe the crossover would seem more natural with just a high pass for the compression driver? because of the very high sensitivity.
I am thinking maybe the crossover would seem more natural with just a high pass for the compression driver? because of the very high sensitivity.
Any further experience/measurements with the P Audio coaxes? Otto88 especially, as I have found my set of BM15CX38, still NIB with the blue straps around them and am wondering whether to use them or sell them and get back the space.
Panomaniac, I have seem you mention that you have tried, or are using a PAudio 12" coax unit; is it a BM or SN series unit?
Panomaniac, I have seem you mention that you have tried, or are using a PAudio 12" coax unit; is it a BM or SN series unit?
Been following this thread with high interest.
And I've been thinking of picking an 8" coaxial for my Oris horn. However, there's a major concerns of directivity. The published datasheets of most of these coaxials show 90 degree conical directivity. So, when the whole coaxial unit is loaded by a front horn or waveguide (which is for the LF section of course), ideally the HF section should not be interferenced.
I'd guess this can only be done by some kind of very shallow and wide flared waveguide. Otherwise the wide dispersion of HF would inevitably hit the inner wall at probably the middle section of most curvy sided horns. Must be a bad thing... 🙁
By this I think of Tannoy. Isn't there a model or two coming with complex compound horn? (The big coaxial is loaded both front and back.) The front horn portion looks quite shallow, but I'm not sure if shallow enough, especially in the horizontal direction.
Of course, there're the dilemmas in loading, directivity control, and the combination with the HF section. After all, leveling the difference of sensitivities of both sections in coaxial is not easy.
Maybe the critics to the BMS coaxial compression drivers are rooted in the same thing, even the mis-matches in those CDs are smaller.
Any thoughts or experiences?
And I've been thinking of picking an 8" coaxial for my Oris horn. However, there's a major concerns of directivity. The published datasheets of most of these coaxials show 90 degree conical directivity. So, when the whole coaxial unit is loaded by a front horn or waveguide (which is for the LF section of course), ideally the HF section should not be interferenced.
I'd guess this can only be done by some kind of very shallow and wide flared waveguide. Otherwise the wide dispersion of HF would inevitably hit the inner wall at probably the middle section of most curvy sided horns. Must be a bad thing... 🙁
By this I think of Tannoy. Isn't there a model or two coming with complex compound horn? (The big coaxial is loaded both front and back.) The front horn portion looks quite shallow, but I'm not sure if shallow enough, especially in the horizontal direction.
Of course, there're the dilemmas in loading, directivity control, and the combination with the HF section. After all, leveling the difference of sensitivities of both sections in coaxial is not easy.
Maybe the critics to the BMS coaxial compression drivers are rooted in the same thing, even the mis-matches in those CDs are smaller.
Any thoughts or experiences?
I thought of doing the same thing with an Azura horn a while back, but went down a different path. I had similar concerns, but maybe getting a driver and testing it would give a definitive answer.
Here's one idea from Danley, the SH100
Not a very good pic on the site, but I have a better one here somewhere and will post it later if I can find it. The driver is a B&C 8" coax, but am unsure which unit it is. I ordered some 8CX21 to try something similar looking some time ago but they went MIA.
Tannoy use a front loading of the driver in the Westminster and some of the older units as well IIRC.
Here's one idea from Danley, the SH100
Not a very good pic on the site, but I have a better one here somewhere and will post it later if I can find it. The driver is a B&C 8" coax, but am unsure which unit it is. I ordered some 8CX21 to try something similar looking some time ago but they went MIA.
Tannoy use a front loading of the driver in the Westminster and some of the older units as well IIRC.
An externally hosted image should be here but it was not working when we last tested it.
Yes I've also noticed that SH100, a very interesting speaker.
Its directivity is 110 degree, as I've mentioned it'd better be wide. And I believe the WG is more of a directivity control, less of loading. As the sensitivity is 'only' 95dB/2.83v...
Its directivity is 110 degree, as I've mentioned it'd better be wide. And I believe the WG is more of a directivity control, less of loading. As the sensitivity is 'only' 95dB/2.83v...
Here's some measurements I took of a 15" UBaffle coax 1 meter away, 1 meter off the floor and gated in a less than optimum baffle. I'm sure the poor baffle design is effecting the response in a negative way even though I have improved it to a certain degree, but it is still far from done right. The crossover is 24db/octave LR around 2kHz(this could use a lot of work as well). I built these prior to knowing the first thing about measuring a loudspeaker's response or modeling software and I'm quite sure that weighs in heavily here.
on axis:
45 degrees off axis:
It has the same look in the vertical plane as well. The tweeter is the cheapest Eminence compression model and may not have the best response to begin with. Where the tweeter meets the cone is the variety talked about earlier where a metal horn sticks out beyond the cone/vc former. Not sure of that's what's causing the raggedness, but it would seem to make sense. I've wanted to try to kill it with some Geddes like foam and possible adding a paper cutout from the termination to the cone, but that's a further on up the road battle. Surprisingly, this thing doesn't kill my ears and actually sounds decent. Tonally it fairs well across the room and sounds better with a different crossover. The tweeter roll off isn't very noticeable if at all unless you are concentrating on listening for it. My wife says it sounds nice and big, but not refined. She's never seen the response graphs. She's heard the Heritage line Tannoys and absolutely thought they were fantastic. Told me that if I couldn't build something better by the time I was 50, I could get a pair.
15 years to go. 
Dan
on axis:
45 degrees off axis:
An externally hosted image should be here but it was not working when we last tested it.
It has the same look in the vertical plane as well. The tweeter is the cheapest Eminence compression model and may not have the best response to begin with. Where the tweeter meets the cone is the variety talked about earlier where a metal horn sticks out beyond the cone/vc former. Not sure of that's what's causing the raggedness, but it would seem to make sense. I've wanted to try to kill it with some Geddes like foam and possible adding a paper cutout from the termination to the cone, but that's a further on up the road battle. Surprisingly, this thing doesn't kill my ears and actually sounds decent. Tonally it fairs well across the room and sounds better with a different crossover. The tweeter roll off isn't very noticeable if at all unless you are concentrating on listening for it. My wife says it sounds nice and big, but not refined. She's never seen the response graphs. She's heard the Heritage line Tannoys and absolutely thought they were fantastic. Told me that if I couldn't build something better by the time I was 50, I could get a pair.
15 years to go. Dan
For a WG comparison, here's the same tweeter on a 12" Parts Express waveguide under similar conditions otherwise.
On axis:
45 degrees off axis:
and on the 10" PE WG.
on axis:
45 degree off axis:
Maybe that will help determine what issues are the driver and what is the waveguide. The PE waveguides are not modified and the throat is nasty. The throat looks much better on the coax.
Dan
On axis:
An externally hosted image should be here but it was not working when we last tested it.
45 degrees off axis:
An externally hosted image should be here but it was not working when we last tested it.
and on the 10" PE WG.
on axis:
An externally hosted image should be here but it was not working when we last tested it.
45 degree off axis:
An externally hosted image should be here but it was not working when we last tested it.
Maybe that will help determine what issues are the driver and what is the waveguide. The PE waveguides are not modified and the throat is nasty. The throat looks much better on the coax.
Dan
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