Yeah, this was a problem and why in recent decades accepted that they would need to be strictly 1 WL long conical WGs for 'FR', co/tri-ax for best overall performance.
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If you search a little bit further, you will find the thread below, and there will be great surprises for you. 😀
https://www.diyaudio.com/community/threads/small-format-cone-driver-in-horn-thread.306492/page-6
see posts# 37, 104, 107, 115
Here's a version with pretty good polars...
https://quint-store.com/lautsprecher-bausaetze/kompaktlautsprecher/h-a-v-o-f-a-s-t-studio
https://quint-store.com/lautsprecher-bausaetze/kompaktlautsprecher/h-a-v-o-f-a-s-t-studio
No, it's "normal" driver. There's no dip around 7-8kHz, no cancelation as always are mentioned without phase plug?
https://quint-store.com/media/files...cb52e6fd2327ecaa/Herstellerdaten-NE65W-04.pdf
The Sb Audience/acoustics SB65WBAC25-4 may be worth a look, from memory the surround is just over 50mm (2") in diameter. very good performance, and a pretty good price.
to the folks recommending an "oversized" driver: in practice this will cause some HF cancellations, correct? or can the air mass between the surround and the horn flange be made small enough not to matter?
I think you would have to then consider a throat adaptor or something to round over the gap that fits the driver profile. IMO becomes too complicated. Unless you have a 3d printer and some more time.
assuming you could make anything, you would still have to give some sort of clearance to the surround and/or cone, even if only a millimeter or two, creating a volume of air that is constricted by the horn throat. will that volume of air be "seen" by a HF wave, say 1" wavelength at 13.5Khz? or will it be invisible?
Hello 🙂
I have been working on a project for quite a long time. In fact, I have implemented exactly this idea that you discusses here. When I saw this thread here I thought, it's time to share this with you. Don't get mad at me please, I've created a separate thread for it - I've named it "SB-Horn V3".
https://www.diyaudio.com/community/threads/broadband-driver-unity-horn-sb-horn-v3.381322/
Best regards, Christian
I have been working on a project for quite a long time. In fact, I have implemented exactly this idea that you discusses here. When I saw this thread here I thought, it's time to share this with you. Don't get mad at me please, I've created a separate thread for it - I've named it "SB-Horn V3".
https://www.diyaudio.com/community/threads/broadband-driver-unity-horn-sb-horn-v3.381322/
Best regards, Christian
Well that's what physics would tell you (assuming there is no phase plug or some-such to alter path lengths). Just for fun, I tried it several years ago and got exactly the response one would have expected. That said, subjectively it didn't sound bad. Without a direct comparison to actual flat response the ear/brain is surprisingly tolerant.
I only tested it in the horn and on unfiltered 1m wide baffle in room. There are plans to make a wave guide + try it on a flat baffle with a 12 inch😱) But the measurements from HobbyHifi promised a good result...
It's not very expensive, try it yourself!
...so, I am reposting my questions so I can answer them here myself, thanks to this post from Art Welter:
"A high frequency compression driver's clearance between the phase plug and the diaphragm is no more than 1mm, 0.5 mm being more common. A gap of 2mm would lower the acoustic band-pass, attenuating high frequencies to the point where an additional tweeter would be required.
The .5mm clearance puts an absolute limit to the excursion, and low frequency output potential of a 2" diaphragm high frequency driver on a conical constant directivity horn to around 110dB at 700Hz. If more output is required, a higher crossover point is must be used, at 800Hz, excursion would be cut in half, so SPL could be increased to 116dB, at 900Hz, excursion drops in half again, output in the 122 dB range."
https://www.diyaudio.com/community/threads/bend-it-like-bateman.378855/post-6834872
With this information I have decided that the HF driver must fit inside the horn throat to preserve the precious top-octave response of the "full-range" driver.
I've ordered the Aura NSW2, hopefully I will like its distinctive sound. I will post measurements when I can.