Full Test --- ES-290 Biradial Horn + JBL 2446H 

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.

your work is simply amazing .. thank you for sharing

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...

I’d love to see how the 2446 performed with a Be diaphragm

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.

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

Very interesting! in germany we say : "Unter Pegel trennt sich die Spreu vom Weizen". this means for SPL usage you will get massive differences

Nice work!

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.

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.

Really nice.. I hope your friend would also make carbon fiber frams for GPA/Altec 902 and 802 drivers. The waterfall plot looks impressive.

1:50 I am actually proud that my speakers can reproduce your kids screaming in another room.

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.

Is it possible to build two more of the horns? A friend of mine would probably buy two pieces Greetings

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.

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 .

It'd be interesting to see the results with beryllium diaphragms, possibly with the JBL 2447 with the 1.5" throat opening.

You’re a great dad!

in my point of vew Arai 290 ils the best horn for a 2 way driver system

Need to swap to a aquaplas coated diaphragm mate. Get the 16 ohm version to drop noise floor.

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).

What is your opinion on 288 drivers?

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.

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.

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