Anything Beyond The Bicor 20 for the Lowther DX55?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
It’s that time again: A call for cabinets for the Lowther DX55 Driver.

This comes up every so many years, with very little success for the OPs. I am finding virtually nothing online. I will be buying the Lowther cabinet CD shortly. The Bicor 20 does not appear to be that difficult for my carpenter to make.

Is there anything out there?
 
There is a design called Alerion for the dx65 that could be of interest though I don’t know if thr plans are freely available.
Something like a similar looking smaller Fostex factory horn cabinet might be ok, perhaps worth trying one in cheap material to test.
 
talaerts -

Thanks for the suggestion.

The Alerion appears to not be a public-domain design. Something along the lines of the BK-12m would be nice, which is ironic because I was considering that kit for the FE126En until a few days ago, when I found the Lowthers online.

Regards,

Karl
 
Scott -

That would be very much appreciated by me & others in the community who are limited by the dearth of plans. Thank you!

I won’t be able to measure them for a while. You mentioned several years ago that the published parameters don’t match the actual ones.

I’d be happy to pay for any plans, even if they are shared here.

Regards,

Karl
 
Last edited:
Hello Karl,

Not a problem. I should have done something for Lowthers a long time ago, but time & tide...

In fairness to Lowther, leaving reasonable sample variability aside, it also depends on the measurement hardware / software; drivers like Lowthers can be somewhat more sensitive to this than others. In general I try to build some leeway into designs to account for this, along with amplifier output impedance &c.

No charge from me for custom work; if anything is received for plans, I try to ensure it goes to Dave, which is only fair as he has to do the hard work drawing up the designs. Same applies to the designs on the Woden site -doubly so there since he also designs & hosts the site.
 
Ah, the DX-55... This is a very special driver, BUT is not a wide bandwidth driver, more like a mid-tweeter. My memory is a bit foggy on the details since this was over 10 years ago. but here goes:

There is a huge rise in the treble region (5kHz - 10kHz?) that must be dealt with. No cabinet is going to compensate for this rise in the low/mid end. I tried 2 rear loaded type horns (Z-horn and huge BiiB) that brought the 200Hz and below region up, but not nearly enough to compensate for the treble rise not to mention the hole in-between. This may explain the lack of box plans for this driver. The obvious way is via a broad notch, which unfortunately kills the aliveness of the driver. Electronic eq works to an extent until you burn out the voice coil. I tried Rethym phase plugs, Deckert's adjustable inductor, cutting off the whizzer and cone treatments that did nothing but kill the sound. In the end I destroyed 3 sets of cones, albeit somewhat mitigated by Jon Ver Halen (who ran Lowther America at the time) who sold the cones to me at cost to accommodate my experiments. The only thing that worked for me was front horn loading the driver down to about 250Hz mated to a 15" Altec 604e woofer. I stopped after the 3rd set of voice coil burned out.
 
Alerion Drawings

It is time I let these go into public domain.

They require a 1mH coil in parallel with a 12ohm resistor acting as a baffle step correction to sound right.

Enjoy,
Jon

Oh, BTW, I do have phase plugs for you. Contact me at my new address, jon at refined audio dot com No spaces, of course.
 

Attachments

  • Alerion .pdf
    86.6 KB · Views: 137
Alerion plans

Finally, in .dwg format. You can download any number of .dwg viewers, and they are a lot easier to read and manipulate if you do.

Hope you have some fun. Make sure to add damping to the back of the compression chamber. To much makes the sound dead. Usually the back wall, and then in the upper and front corners. I used 1/4" wool felt on the back, and cut it into 1/4" wide strips for the corners.

Best,
Jon
 
I tried one driver today, in a large sheet of heavy corrugated cardboard.

I liked the sound a lot. Pretty tipped-up in the treble. Fast-sounding. Definitely could be pretty revealing. Piano, koto, violin, and percussion were very nice. By far the most sensitive drivers I have worked with. This would be a great opportunity to try an SET amp

There’s a lot of potential. I am over the first hurdle: I like them. I was worried about that. Although I got them “used”, they were very expensive for me. I’m looking forward to working with them.
 
Last edited:
no- that is JBL's shape

here is the famous RJ "lemon" aperture
https://i.imgur.com/6QFbGJ9.jpg
https://www.vinylengine.com/turntab...e.php?mode=medium&album_id=255&image_id=21205

here's the earlier RJ aperture shape
Nice page with R-J experiment

the RJ (and later "Eliptoflex") cabinet had dual ducts which fed the rear wave into the front aperture
a single ended amp with little or no negative feedback (or series resistor with sand amp/PP FB tube amp) might your speakers qts enough for reflex action

Dr. Scottmoose's proper blh would be better than reflexing - but you can experiment with that hourglass lens. I don't think R&J had dispersion in mind with their lemon aperture - more likely an avoidance of cavity effects
 
During a conversation I had this afternoon, I complained that I had made a mistake in purchasing the DX55 drivers. He suggested the Madisound BK-16 horns. I know someone here on this forum tried it with some success.

Opinions on the idea?
 
Last edited:
This is not a news flash, but I know there’s been a bit of interest in a new cabinet for the DX55: I’m selling them. Please PM me if interested.

The suggestion of using the Madisound BK-16 BLH cabs was interesting, but too speculative.

Scott - Thanks very much for working on something, but I’m moving on. I should have done my homework.
 
Last edited:
This is not a news flash, but I know there’s been a bit of interest in a new cabinet for the DX55: I’m selling them. Please PM me if interested.

The suggestion of using the Madisound BK-16 BLH cabs was interesting, but too speculative.

Scott - Thanks very much for working on something, but I’m moving on. I should have done my homework.



I don’t understand. The Alerion was a well regarded cabinet for your smaller Lowther, and the plans were posted above. Why don’t you just try it? Perhaps in cheap wood first to get an idea.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.