The ScanSpeak D2904/7100 is similar to the Ellipticor D3404. Similar high sensitivity and power handling. It is 40% cheaper.
The Satori TW29DN-B is also high sensitivity, and it is quite a bit cheaper than the ScanSpeak options.
The Satori TW29DN-B is also high sensitivity, and it is quite a bit cheaper than the ScanSpeak options.
Indeed Cinema are not asking the same ISO curves and spl level for the very few I know. The listening fatigue has more to see with the final ISO curve you need than compression driver or soft dome or the radiation patern. Anyway, a lot of the >15k Hz are absorbed by just a painted side wall, not talking about the seat roofs. But maybe a cinema monitoring room is special (controled directivity needed ?)
Is there a THX requirement proof loudspeakers ?
Is there a THX requirement proof loudspeakers ?
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Sorry to go OT, but hifijim is the principal designer of the above system. With his permission, if he allows it, we will put it out to the public domain, when it is ready.
You can discuss any aspect of it you wish... it is your project, I am just helping out a bit.
I would not say I am the principal designer... Audiothings approached me with a really solid concept using these drivers and asked for some advice. I gave some advice on cabinet design, baffle layout, and bracing strategy. I am doing some work on the hypex filter design. I was enthusiastic about working with such high quality drivers in a soffit mounted (IB) design. It is very satisfying to see it progress to this state.
j.
I would not say I am the principal designer... Audiothings approached me with a really solid concept using these drivers and asked for some advice. I gave some advice on cabinet design, baffle layout, and bracing strategy. I am doing some work on the hypex filter design. I was enthusiastic about working with such high quality drivers in a soffit mounted (IB) design. It is very satisfying to see it progress to this state.
j.
It is the outcome from the thread you started a year ago Audiothings ( or more can't remember)?
Congrat to both of you! That rocks! 😀
Congrat to both of you! That rocks! 😀
Not a soft dome but i would also suggest the Bliesma T34A-4/B-4. The AL/MG version is cheaper and has remarkably good sipersion for it's size, high power handling, large xmax and low distortion. It is the closest you come to your requirements that is easily available. And it keeps it's composure very well at high spls. As mentioned previously.
You will find some measurements at hificompass, vcl labs etc.
You will find some measurements at hificompass, vcl labs etc.
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This 1st answer is still the best - just look for xmax vs. diameter (..and add a bit more to that excursion unless you use a near brick-wall high-pass).
Putting in a 1" driver at 120 db at 3500 Hz results in .9mm of xmax, add a bit to that with something like an elliptical high-pass filter and you are around 1mm of xmax. If you want another +3db from that (123 db) then go up about 500 Hz on your low-pass filter (to 4000 Hz); about 5500 Hz for 128db.
Ex.
BlieSMa T25S-6 (pre-production sample) | HiFiCompass
BlieSMa T25S - €109.80 : AUDIO-HI.FI, Loudspeaker shop
Note: the face-plate on this tweeter is relatively small so you can get the tweeter much closer to the midrange to improve vertical dispersion character.
You can significantly lower that xmax with horn-loading at those lower freq.s depending on how much spl-gain the loading provides near the crossover point..
Ex. using some common waveguides:
Zaph|Audio
Putting in a 1" driver at 120 db at 3500 Hz results in .9mm of xmax, add a bit to that with something like an elliptical high-pass filter and you are around 1mm of xmax. If you want another +3db from that (123 db) then go up about 500 Hz on your low-pass filter (to 4000 Hz); about 5500 Hz for 128db.
Ex.
BlieSMa T25S-6 (pre-production sample) | HiFiCompass
BlieSMa T25S - €109.80 : AUDIO-HI.FI, Loudspeaker shop
Note: the face-plate on this tweeter is relatively small so you can get the tweeter much closer to the midrange to improve vertical dispersion character.
You can significantly lower that xmax with horn-loading at those lower freq.s depending on how much spl-gain the loading provides near the crossover point..
Ex. using some common waveguides:
Zaph|Audio
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ah, and still the Peereless 1.1/4" Corundum dome tweeter 🙂
https://www.parts-express.com/pedocs/specs/264-1678--peerless-da32tx00-08-spec-sheet.pdf
I"ll have a look to some big sized Audax tweeter in a WG as Troels Gravsen did in his Open Bafle OB15 design
https://www.parts-express.com/pedocs/specs/264-1678--peerless-da32tx00-08-spec-sheet.pdf
I"ll have a look to some big sized Audax tweeter in a WG as Troels Gravsen did in his Open Bafle OB15 design
I can not think of any soft dome tweeters that will play at that level, and survive.
My first thought was a compression drive, or even a Piezo.
I remember a small obscure little speaker company back in the early 80's who used a Piezo for the tweeter of their 3 way speaker. It sounded pretty decent too, but the owner of the company told me he had to go through 50 tweeters, to get a couple good ones.
My first thought was a compression drive, or even a Piezo.
I remember a small obscure little speaker company back in the early 80's who used a Piezo for the tweeter of their 3 way speaker. It sounded pretty decent too, but the owner of the company told me he had to go through 50 tweeters, to get a couple good ones.
Here is one with a fairly deep-well waveguide/horn that as a result has more gain than normal and also includes a decent .7mm of excursion. The price it pays as a result of that horn is the dispersion profile with increased directivity.
Dome tweeter Audax PR125T1, 8 ohm, 1.0-inch voice coil, 3.94 inch front side
Dome tweeter Audax PR125T1, 8 ohm, 1.0-inch voice coil, 3.94 inch front side
Definitely something wrong with that online calc. Compared it to manual calculation as well as VituixCAD and WinISD. The online piston calc underestimates SPL by several dB. A little too tired to try to track the error down this moment. An equation for a piston's peak SPL response is given by
P= 2π * f² * Sd * Xmax * ρ / r
ρ is air density, r is distance from driver. SPL peak (3dB more than RMS) in SI units is roughly:
94 + 20log(P)
check out this thread:
99db dome tweeter without titanium and without horn ?
(similar question but other headline).
99db dome tweeter without titanium and without horn ?
(similar question but other headline).
I pulled up a random 12" driver, the JBL CS1214 in my copy of WinISD. Default 0.707 qtc sealed box, power level chosen to correlate to 12 mm excursion at 20 hz.
Compared to the online calculator at 12 mm xmax for a 12" driver: WinISD simulation: 96.873 dB. The piston excursion calculator online shows 95.92 dB.
+ / - 1 dB more or less.
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The piston excursion calculator:
Piston Excursion calculator
Uses this basic piston formula:
SPL = 112 + 10 * log(4 * pi^3 * Ro / c * (num * Vd)^2 * f^4)
Vd = (.83 * diam)^2 * pi / 4 * Xmax
The .83 diameter reduction of the nominal driver size in figuring Vd (displacement volume) to estimate Sd (effective piston area) may be close for some drivers, not so close for others.
The “12 inch” JBL CS1214 Sd is 85.4 square inches.
85.4 square inches is the area of a circle with a diameter of 10.428 inches.
10.428/.83=12.56 inches.
Using the piston excursion calculator with a driver size of 12.56 inches brings the 20Hz 12mm Xmax output to 96.72, very close to your WinISD sim of 96.87.
Using the ScanSpeak Ellipticor D3404/5520-00 tweeter from the OP as an example, it’s effective diaphragm diameter is 38mm. Converting that diameter to inches (1.496) and using it’s 0.25mm Xmax, the piston excursion calculator estimates 2500Hz @110 dB SPL @ 1m, which as Briskly points out, is too low.
Compensating for the .83 reduction of the diameter, 1.496/.83=1.8 inches. Using 1.8 inches as the diameter, the SPL rises to 113.22, over 3 dB difference.
The driver is rated for 180 watts and a 94 1w/1m sensitivity, so has 116.5dB potential output only slightly exceeding Xmax at 2500Hz.
It’s Xlim is 2mm, so it’s underhung voice coil could potentially create 131.2 dB SPL, though would require around 11,000 watts to do so, insuring that would be a one time event 😉.
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Look to larger 1 1/8 domes and wave-guides or horn loading. Look into the concepts from Earl Geedes.
Don't know what you are trying to do, but I have no use for SPLs that can damage my hearing.
Don't know what you are trying to do, but I have no use for SPLs that can damage my hearing.
I was searching a for a high sensitivity dome tweeter with relatively low crossover (2khz).
Thanks for identifying the closest thing to the holy grail.
The only way to increase values is using WG/Horns. If dispersion narrows then you get this sound on-axis, and gains can be quite substantial, but I don't think that 129dB SPL i doable (or that there's way of making use of it in the real life).