Yes, it's the 15ob350. With the Hypex modules and lots of compensation for bass below 50Hz it goes easily down to 25Hz. The other way round: when I play really loud I can bring the 250W of the FA123 module into clipping (with suitable low-bass heavy music). Compared to classic bass reflex you get a more precise bass, and with the DSP I can compensate for room modes, thus no one-note boom.
I tried also a passive x-over and bass compensation via the Wiim EQ, but in that mode the bass is a bit less precise. Not end of the world but not my favourite.
With the bigger horns I could think of a 400Hz XO with horn in passive mode, driven by tube amp and bass actively controlled (like Troels Gravesen often does with woofers below 200Hz)
I tried also a passive x-over and bass compensation via the Wiim EQ, but in that mode the bass is a bit less precise. Not end of the world but not my favourite.
With the bigger horns I could think of a 400Hz XO with horn in passive mode, driven by tube amp and bass actively controlled (like Troels Gravesen often does with woofers below 200Hz)
What does troels with the hypex module and realy good amp for the upper section Is definitly a good idea even if I don't understand why he try to match sensitivity between bass and mid-tweet even in those cases.
I want to try a 8nmb420+tw29txn and a 15ob350 bass section. I just don't know if I go open baffle or closed... Or a mix ^^
Plan is to start fully active but I will try to go passive between mid and tweet to try a dht tube amp
I want to try a 8nmb420+tw29txn and a 15ob350 bass section. I just don't know if I go open baffle or closed... Or a mix ^^
Plan is to start fully active but I will try to go passive between mid and tweet to try a dht tube amp
Update on the Yuichi A290 horn (with some mods).
- sanded and filled a bit (I focused on the part I'd see as a listener)
- filler colour came out with a green tinge - not the final paint colour for sure (should I go grey? or white?)
- added a modded "furniture height adjuster" from thingiverse. I printed the bottom part in TPU95A, because that's such a well damped material
- used gel pads on the bottom of the horn, resting on the wood of the bass cabinet
- with the FaitalPro HF1460 driver I didn't even need much EQ to get a fairly flat quasi-nonechoic response (will add measurements with different drivers later
- chose 500Hz XO frequency for the moment, 48dB/octave and 0.96ms delay on the woofer (32cm further in the front than the HF driver)
- quite happy with the sound so far. Integration with thw oofer is much easier with this lower XO frequency.
Attachments
Congrats on this build! I'm very curious about the FaitalPro HF1460 driver, which NicoB also recommends for use with this horn. https://audiohorn.net/x-shape-horn/
https://audiohorn.net/test/compression-driver/1.4inch/
What was the crossover frequency which finally worked best?
Can you provide some details about the sound of the HF1460's HF response?
Last edited:
Here's some measurements on the HF1460 in the A290 horn. Quasi anechoic (gated, 4ms) measured via an -20dB LPAD, with ca. 0.6V RMS signal level at the voice coil.
Definitely wants some EQ if you run it full range from 500Hz - 20kHz. Falls off after 14kHz, which is fine with me / my ears.
Also interesting that the level doesn't fall off that much when you go off-axis (measured here at 15 and 30 degrees)
And here's the distortion (all below 1% at > 96dB sound pressure) from the on-axis measurement above.
Another plot on the A290 with three 1.4" drivers, 4ms gated (quasi-anechoic), ca. 0.6V RMS signal level
The smaller drivers go easily to 17kHz, while the bigger dome of the HF1460 ends at about 14kHz.
- RED: FaitalPro HF1460 with Joseph Crowe back chamber (carbon fiber, 86mm/3.4" voice coil)
- BLUE: SB Audience Rosso 65CDN-T with Joseph Crowe back chamber (titanium, 65mm/2.5" voice coil)
- GREEN: FaitalPro HF144 in stock configuration (ketone polymer, 65mm/2.5" voice coil)
The smaller drivers go easily to 17kHz, while the bigger dome of the HF1460 ends at about 14kHz.
Nice looking horn print!
Interesting that the response below ~700 Hz is -2dB @30 degrees off axis, but above 7kHz within 1dB.
What is the mic distance from the horn mouth?
Is the axis of horn rotation at the throat, mouth, or some other point?
Interesting that your measurement of the little HF144 has +4dB at 800Hz over the HF1460 (with enlarged chamber), while Faital's measurements show both within 1dB on the LTH142 horn:
The response of your HF1460 also looks considerably more "lumpy" than Faital's measurements (almost twice the +/- deviation), while the HF144 mirrors theirs fairly closely.
Have you measured the HF1460 with the stock back chamber?
If you have another HF1460, have you compared the two drivers for consistancy?
Art
Good point, Art. I first thought the LPAD and the impedance curve of the driver might cause irregularities, but it is in fact the Joseph Crowe rear cover. On this horn, it produces a suck-out in the 500...1500 Hz region. So, that's pretty much the 4dB difference that you saw.
All measured directly / without LPAD, UMIK-1 in 1m distance, gated at 4ms (quasi anechoic)
ORANGE: driver A, HF1460 @96dB, Joseph Crowe No.2021 rear cover
RED: driver B, HF1460 @96dB, Joseph Crowe No.2021 rear cover
CYAN: driver B, HF1460 @96dB, stock rear cover
BLUE: driver A, HF1460 @96dB, stock rear cover
Also, the freq extension of driver B is better than A. Not sure if I'll be able to hear that in real life.
All measured directly / without LPAD, UMIK-1 in 1m distance, gated at 4ms (quasi anechoic)
ORANGE: driver A, HF1460 @96dB, Joseph Crowe No.2021 rear cover
RED: driver B, HF1460 @96dB, Joseph Crowe No.2021 rear cover
CYAN: driver B, HF1460 @96dB, stock rear cover
BLUE: driver A, HF1460 @96dB, stock rear cover
Also, the freq extension of driver B is better than A. Not sure if I'll be able to hear that in real life.
I'd expect it would do the same on most horns, the driver's compliance was designed with a specific "air spring" in mind.
-3dB at 15kHz would be hard to notice by ear in anything but an A/B test with individuals that can still hear that high. Been around 15 years since I could hear under 80 dB at 16kHz in my right ear, longer than that for my left 😢
Other than the VHF, the HF1460 drivers look almost perfectly matched.
A slight increase of diaphragm mass could reduce the VHF, - since you printed a back cover, you might use a magnifying glass and look for a tiny fleck of plastic debris on the "A" diaphragm.
Still curious, what was the axis of horn rotation in the off-axis measurements ?
Art
Another measurement, this time in-room and not gated. Below 400Hz the response of the A290 falls off the cliff.
That (frequency) falls in line with Joseph Crowe's measurements on the A290: https://josephcrowe.com/blogs/news/smooth-transition-throat-adapter-no-2322-for-yuichi-a290?_pos=2&_sid=2085a5871&_ss=r
Some of the lumps in the measurement can be room resonances.
BROWN:FaitalPro HF1460 on A290 horn, in-room, mic ca. 67cm away from the driver (i.e. close to horn)
GREEN: FaitalPro HF144 on A290 horn, in-room, mic ca. 67cm away from the driver (i.e. close to horn)
That (frequency) falls in line with Joseph Crowe's measurements on the A290: https://josephcrowe.com/blogs/news/smooth-transition-throat-adapter-no-2322-for-yuichi-a290?_pos=2&_sid=2085a5871&_ss=r
Some of the lumps in the measurement can be room resonances.
BROWN:FaitalPro HF1460 on A290 horn, in-room, mic ca. 67cm away from the driver (i.e. close to horn)
GREEN: FaitalPro HF144 on A290 horn, in-room, mic ca. 67cm away from the driver (i.e. close to horn)
That was the horizontal axis. I measured on-axis, 15 and 30 degrees to the left of the horn center.
... and just for comparison with the A290, here is the HF1460 driver on-axis with the Joseph Crowe ES450 horn. Output falls off below ca. 500Hz compared to the 400Hz of the A290, and the frequency response on-axis is more even.
RED: HF1460 on ES450 in-room measurement, 67cm away from the driver, on-axis
BLUE: HF1460 on ES450 gated (4ms) measurement, 67cm away from the driver, on-axis
That more linear/horizontal FR comes with the consequence of narrower dispersion at higher frequencies.
Off-axis measurements and a polar map are here on Joseph/Troy's website: https://josephcrowe.com/blogs/news/es-450-biradial-no-2143
RED: HF1460 on ES450 in-room measurement, 67cm away from the driver, on-axis
BLUE: HF1460 on ES450 gated (4ms) measurement, 67cm away from the driver, on-axis
That more linear/horizontal FR comes with the consequence of narrower dispersion at higher frequencies.
Off-axis measurements and a polar map are here on Joseph/Troy's website: https://josephcrowe.com/blogs/news/es-450-biradial-no-2143
Those are the "1in4 William Neile ALO horn" shown on sphericalhorn.net? Are plans available to purchase?