High power, high sensitivity tweeter at 20Khz

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guyst

Member
Joined 2010
#1
Hi to all,

Im looking for a high power (100W+) tweeter that has high sensitivity at ~20KHz. So far my best find is DS18 PRO TW120 which, according to the website graph, puts out 105db at 20KHz; but its a 60W driver so not very powerful. Other considerations are secondary (sound quality, impedance, size, etc). I simply need maximum SPL at ~20KHz.

Thanks
 
#6
Evil?? how can this do evil? its a tweeter. Its part of a test setup for a product Im developing. I cant elaborate much as its in very early stages and not patented.
I can say it involves transferring data using ultrasound.
Why are you so suspicious?
 
#7
billshurv said:
if it only needs 60W to produce 105dB how is that not powerful?

Sound like you need to think about a very narrow beamwidth horn for this application
Click to expand...
Actually the 105db figure is achieved at 2.83Vrms input so much less than 60W. Even so, for my app I need more power. There are very powerful tweeters out there but few of them come with frequency response graphs, and most of those who does fall sharply before 20KHz.
 
#9
https://audioxpress.com/article/test-bench-the-bms-1-5530nd-high-efficiency-compression-driver
perhaps the HF portion of this: https://www.bmsspeakers.com/index.php-96.html?id=bms_4594he0

Beyond that I guess a combining manifold and or very narrow directivity horns (if at range a parabolic reflector), the manifold probobly won't be coherant at 20kHz so expect +3dB for each doubling of the number of drivers. Exotic options perhaps some kind of plasma driver, horn loaded. You could also try a focused array if you have a particular target point.
 
#11
kipman725 said:
https://audioxpress.com/article/test-bench-the-bms-1-5530nd-high-efficiency-compression-driver
perhaps the HF portion of this: https://www.bmsspeakers.com/index.php-96.html?id=bms_4594he0

Beyond that I guess a combining manifold and or very narrow directivity horns (if at range a parabolic reflector), the manifold probobly won't be coherant at 20kHz so expect +3dB for each doubling of the number of drivers. Exotic options perhaps some kind of plasma driver, horn loaded. You could also try a focused array if you have a particular target point.
Click to expand...
Thanks for the options! I will very much appreciate a link to info regarding design of said horn and parabolic reflector. Do you think adding a well designed horn to the super tweeter I found will increase SPL significantly at a narrower angle?
 
#13
Tom Danley's apparatus for acoustic levitation was capable of over 160 dB at around 22kHz (IIRC) at a short distance, using piezo transducers.
https://patents.google.com/patent/US5036944A/en

This thread might get you started in the parabolic or hyperbolic reflector concepts:
https://soundforums.net/community/threads/hyperboline-tm-new-player-in-the-old-game.7452/

Joseph Pompei's Holosonics Audio Spotlight speakers use around 60kHz carrier waves to produce sound in the audible range.
That tech could be used for focusing sound waves in the frequency range you are interested in.

https://docplayer.net/50330179-The-...onics-for-generating-audible-sound-beams.html

Joseph Pompei The Use of Airborne Ultrasonics for Generating Audible Sound Beams.png

At any rate, be careful- even though you can't hear 20kHz, it will still damage hearing.
I found that out while doing ultrasonic tests starting at post # 179 in this thread:

https://www.diyaudio.com/community/...ts-of-adding-hf-driver-7khz-up.210914/page-12

Art
 
#14
Thanks art, that's fascinating stuff! Did you suffer permanent hearing loss from exposure to HF sound? If so, what kind of dosage? I couldn't make that out from the thread.

Also, where can I find info about design of the Maltese horn? Google is silent on it... From what I gather here the horn is the simplest way to achieve highly directional loud HF, albeit at lower performance. Is that true?
 
#19
guyst said:
Thanks art, that's fascinating stuff! Did you suffer permanent hearing loss from exposure to HF sound? If so, what kind of dosage?
Click to expand...
I have permanent noise induced hearing loss from exposure to HF sound, though not from one single event.
The NIOSH acceptable daily dosage of 15 at 100dBA, and only one minute at 110dBA "slow" gives an idea of how little is too much.
guyst said:
Also, where can I find info about design of the Maltese horn? Google is silent on it... From what I gather here the horn is the simplest way to achieve highly directional loud HF, albeit at lower performance. Is that true?
Click to expand...
A very narrow dispersion horn is the simplest way to achieve highly directional loud HF, though consistent response in the VHF range is not.
The Maltese horn is a simple 2 part 13 degree conical horn, pictures can be seen in this thread:
https://www.diyaudio.com/community/threads/high-frequency-compression-driver-evaluation.212240/
The BMS 4552 had the best VHF sensitivity in those tests, here is the on axis response, "0dB" about 110dB 1watt one meter:
BMS 4552 on Maltese horn.png

A more narrow horn would increase on axis sensitivity, and the horn could be scaled down considerably since you are only looking for VHF response.

If the response charts for the DS18 PRO TW120 are correct, they have similar 20kHz sensitivity (105dB at 2.83Vrms into a 4 ohm driver is 102dB) though I'd suspect their 1" voice coils and aluminum diaphragms won't hold up to near as much level as the BMS 4552's 1.75" voice coil polyester diaphragm.

Without a specific SPL level and distance goal and description of the object you want to induce resonance to, can't offer much more help.

Art
 
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