Full Test --- ES-290 Biradial Horn + JBL 2446H
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- Опубликовано: 25 авг 2024
- I test for the first time my ES-290 biradial horn. This is Joseph Crowe exclusive design which is custom built in my shop and available for sale on my website.
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For the blog post related to these tests click below...
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Inspired by the classic Yuichi A-290 biradial my horn shares the same physical size and low frequency cutoff.
Testing was done with a JBL 2446H compresson driver using a custom made throat adapter to mount the driver. The throat adapter was made for testing purposes only. The final driver will be a custom field coil inspired by Western Electric 555.
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It looks like the CF does what it does well and then quits, the JBL props up the upper end with a load of resonances. You are doing more advanced testing than I could when I was younger. I think the PC has allowed us to be able to afford decent speaker tests that would have required huge corporate type budgets back in the 70's. I lashed together some speaker testing back then that worked better than it should have, but I dreamed of spectrum analyzers and plotters that could draw a frequency response graph. In the 90's we bought LMS and that seemed so marvelous and such a bargain (over $1000) back then. Keep up the great work, I enjoy seeing your results.
Thank you, JC. I looked at the JBL 2446H on PE last Black Friday or Christmas decent % off everything sale. Had to go back to the PE site to be sure it was the same driver and noticed the new Celestion Axi2050 which looks interesting, hope you get to work with that one too. Very happy to see you working with the JBL 2446H and beautiful craftsmanship on the bi-radial horn, sparks the interest! As always, I'm looking forward to your updates...
Thank you! Yes I'm waiting to see independence test results on the Axi2050. Like so many other products out there it's impossible to draw any conclusions on the published data. I get daily emails from folks that want to buy a driver based on opinion or misleading published data. For me there's a select few manufacturers that I'll trust and publish reliable data that I can commit to buying for my designs.
Very interesting! in germany we say : "Unter Pegel trennt sich die Spreu vom Weizen". this means for SPL usage you will get massive differences
I’d love to see how the 2446 performed with a Be diaphragm
your work is simply amazing .. thank you for sharing
With regards to your carbon composite diaphragm, you could add a high quality bypass capacitor on the high pass filter in the order of 220nf, 330nf 0r even 470nf to give the driver full power at those highest frequencies. If it produces too much gain, reduce it with a resistor in series.
Magnificent, even your adaptor is a work of art! I have a pair of these CD's so I'll be keeping an eye out for the update on your diaphragm. Thank you.
The carbon composite didn’t perform as good as the titanium.
I have 4 of the 2446. They are acceptable up to about 9 K. Hope you eventually work on the carbon comp dias. again. The greatest flex is near the perifery. Perhaps if you guys stiffened the outer 1/4 of the dome. and thinned the inner half it might stay light enough and yet stiff enough at the outer rim. Surround is also critical. I vastly prefer the surrounds on Radian dias.. they are much 'quieter' than the pleated metal of JBLs. ALL my JBL 1" drivers have Radian dias. in them. I have added 4" extra depth to all my larger alnico 1" exit JBL chambers, filled with long fiber wool. It really helps. At some point I will add a spacer to the 2446 drivers and do the same filler. Love what you do! We need passionate technical artisans such as yourself in our field.
1:50 I am actually proud that my speakers can reproduce your kids screaming in another room.
Really nice.. I hope your friend would also make carbon fiber frams for GPA/Altec 902 and 802 drivers. The waterfall plot looks impressive.
Thank you. After testing two version of the carbon composite diaphragms I don't think I'm able to achieve the performance target I was looking for. However I will be developing my own midrange drivers shortly that are made in-house. So stay tuned for that.
Bummer, looked promising nonetheless! Was the performance target to get higher output above 10KHz or was it something else? Great work, love it!
You’re a great dad!
Nice work!
Thanks!
in my point of vew Arai 290 ils the best horn for a 2 way driver system
Dude. You made a carbon fiber foam sandwich *compression driver*?!
I'll give that a *wow*.
And I will also recommend vectran (much higher damping coefficient).
Joseph do you have any experience with the 1.5" exit version compression driver the JBL 2447 and or the 2381 horn often used with it? Thanks.
No, the 2381 looks decent though.
@@JosephCrowesDIYSpeakerBuilding yes it is a good sounding horn I am using it in the near field and it does not light up the bulk of the room keeping sound well focused. some JBL data says the 2381 is a 90x50 horn and some says it is a 90x40 either way it is a tight focus which can be handy to minimize near wall reflections.
the 2447 exhibits a broad peak in response at about 11.5KHz and I was wondering if you had read or heard what was responsible for this peak? I don't know if it is the diaphragm or the suspension. I is reduced as you go off axis to the horn. I was also curious if you had any experience damping these large four inch diaphragms? I know JBL used to damp both the diaphragm and the suspension with aquaplas. I had the ideas of using a stainless steel primer in spray form applying a single light coating to the entire diaphragm then three more coats on the bottom inch of the diaphragm in three progressively narrower layers so the build up is the thickest at the bottom quarter inch of the diaphragm as this would seem to be the area of the diaphragm with the most break up.. This ought to show some improvement to the high frequency break up unless it is the suspension which is the cause. JBL never worried about this as this driver was intended to be a mid driver used with a tweeter. While I can say the peak looks worse than it sounds I think that this is one of those situations where once removed you would not opt for it back .
Do you have any experience with the Celestion Axi2050? I’m attracted to the absence of a mid to Hf crossover in a full range CD - but I worry that the large diaphragm mass will compromise HF fidelity. Trying for a very high fidelity bi-amped home Hi Fi with Xilica DSP
Need to swap to a aquaplas coated diaphragm mate. Get the 16 ohm version to drop noise floor.
Very nice work Joe. And totally on a good track. Getting as close to 200 hz is the Grail. Have you done any thinking about a unity horn. I like the idea of the point source and conical horn. Just would like your thoughts.
Hi Ron, the unity/synergy horn is strictly by licence only. I pride myself in forging my own path and coming up with creative new products. It's a small industry and so everybody needs to carve out a little piece of their own. However generally speaking conical horns have great pattern control for live sound reinforcement applications however the abrupt horn mouth termination means resonances will be setup which can harm overall sound quality. The mouth termination that I feature on my horns have the fully rolled lip where the sound wave can wrap around to the rear of the horn. This is critical for achieving a hifi sound (my opinion). The next revision of the Nighthawk speaker will feature this rolled lip flare geometry. The first build of the Nighthawk that I featured in a recent video was commissioned for a night club in NY City, and so it needed to be suited for high SPL and space savings. The second build for the Nighthawk will strictly be for hifi and feature the fully rolled lip on the horn mouth for both the HF and MF.
Is it possible to build two more of the horns?
A friend of mine would probably buy two pieces
Greetings
It'd be interesting to see the results with beryllium diaphragms, possibly with the JBL 2447 with the 1.5" throat opening.
😮radian stopped producing beryllium diaphragm.
Idea here maby figure a way to measure the damping material tension like tuning a drum head then compare the differences with the varying pressures
What is your opinion on 288 drivers?
I’ve only heard it in my brother’s system with his A5’s. It’s too hard to know since the multicellular horn adds its own coloration.
@@JosephCrowesDIYSpeakerBuilding and do you like the multicell coloration? You are right tho, driver itself sounds totally different on other horns
0:14 I think you meant to say "2 inch" titanium diaphragm. But seriously, beautiful work. I would love to send you the Altec 290s w/ phenolic diaphragms. It's really more of an apples to caviar sort of comparison (I love apples). Look for my email.
4" diaphragm, 2" exit.
I'll be receiving a pair of Altec 806-8A compression drivers for my next video where I'll be using them on the ES-600 biradial. My brother uses the same compression drivers in his Altec studio monitors and I think the sound is subjectively similar to the TAD TD-2001 with it's smooth and detailed sound. Honestly the JBL has many resonance peaks in the impedance curve and it's a beast of a driver. The RCF ND-950 1.4 with it's 4" diaphragm is significantly better than the JBL 2446H. I'm not sure how the JBL would fare with the new Truextent Beryllium Diaphragms. There isn't a clear choice when trying to select a driver for a 300Hz biradial right now. There are some new compression drivers coming into the market right now but the verdict is still out on their performance for hifi. This is why I've moved to develop the nighthawk speaker which extends down to 200Hz using six 10cm cone midrange drivers which are relatively affordable.
@@JosephCrowesDIYSpeakerBuilding could you compare the bms 4599he with this jbl midrange? Thx
That would be a killer mate with a lascala style folded horn shame their a bitch to find drivers with the correct parameters to make a reasonable size.
I'm not sure the lascala folded horn is such a 'holy grail' of midbass horns. There are other alternatives like the quart pie horn. mapoulin.wixsite.com/audiobymartin/quarter-pie-horn-prototype?fbclid=IwAR0OZOswEa-o19i3BJtX8aszHRnYEe4WWkusCiF6LTxgJ0QRwxT5U2yl6ks