JBL Dynamics Project - Initial discussions

[Macaroonie]

Hear anything good ?

No the ply is rigid but curved. Steaming is part of the process of forming the curve shape. Thats already done for you

 

[hjames]

Have to think a bit about the physics of mounting a 15” woofer on a curved surface ~ but I do like the look!

At the show- we noticed a lot of full range driver systems this year. And a number of clones of vintage design Altec Iconcs, JBL Hartsfields, and others

Hear anything good ?

No the ply is rigid but curved. Steaming is part of the process of forming the curve shape. Thats already done for you

 

[Macaroonie]

You don't have to mount the driver on a curved surface any more than B&W did way back then.
They just made a flat on the inside of the box , you just cant see it coz of the grille cloth

 

[Macaroonie]

https://www.roberts-plywood.com/half-rounds.html

In NY

 

[donprice]

Woah! A big steam box is probably beyond our capability!

Another option is to build a curved frame and bend thin (2.7mm) plywood or MDF and glue up the layers...no steam needed. This would be the solution if you can't match the curvature of the horns with off-the-shelf material.

Here's an example from a build I did a few years ago.
https://www.avsforum.com/threads/eos-10-dna-360-and-deltalite-2510-build.1514560/

Good luck with moving out more speakers to make room for the new build!

 

[Macaroonie]

The nearest half round that Roberts Plywood do is 24" o/d.
Anyone have any idea how that would shake hands with the lip of the Smith horn ?
Next size up is 30" o/d which I think would be getting BIG

 

[hjames]

In a standby pattern right now. The JBL build/project may wait for more thought, perhaps after the Holidays ...
I put the Heils and Horns into a spare room to demo the Heathkit Valencias, and (finally) sold them Nov 10th.

I got some Heathkit AS-1348 last week - they're 40+ year old speakers, so I've have been tweaking them a bit, fine tuning them.
They didn't have the original rear-facing slot-loaded 15" Philips woofers - (got replaced with Dayton 15s!).
So after some thought, I popped the JBL 2216Nd woofers in their place and have been playing with them for now. I think they're breaking in nicely - I noticed some deep bass on a couple Qobuz tracks yesterday.

Touched up some minor chips in the veneer, bought new grill cloth for those upper Mid/Tweeter grills, bought some
casters to put underneath so I can move them easier, and am looking to recap them to get them at their best.
I do like the look of them and they sound pretty good - for now at least.
(Could still get rid of the Von Schweikert VR-4s and the Walnut finish L212s- I'll keep the teak L212 pair for now)





They do like nicer than the faux Valencias in the morning sun ... Sounds good too.

 

[hjames]

So, a week back I was given a pair of the Philips W8W 15" woofers for the Heathkits, and dropped them off to John at Scavenger Sound
in Glen Burnie for check-out and repairs. No rush on them, he's swamped through New Year, so I'll get a progress report sometime in the new year.

The next Project here is to stack the 2 pair of L212s, see how they play that way, & afterwards probably sell off the walnut pair of them, and keep the teak pair.
Whatever will I do with that empty floor space??
Maybe it's time to look at the JBL Dynamics system again (aka, new era L200s).
I'll have to pull the 2216Nd woofers out of the Heathkits, and find time to talk to the cabinet designers for the possibilities.

Update - the Von Schweikert VR-4 sale is canceled. I had boxed them up and was listening to the Heaths with the JBL 2216Nd woofers and - they just don't compare on the bottom end. The VR-4s are amazing.
I gave him his money back when he came for them yesterday, great sadness - but - I'll never find another pair of speakers like them for that kind of money.

They were a present from Emma - after we demoed them at @jjohnson's place Friday, she offered to pull money from her ATM for the pickup Sunday (we were in Richmond anyway in late october for the Celtic Festival, dropped by for a demo, and were flat gobsmacked). She reminded me of that early Saturday ...

Anyway, listening to them lately with the Jolida tube amp has not been doing them justice - the higher wattage of the Carver reminded us what they are capable of.

(Next I need to feed them with a better amp, like the B&K ST202plus downstairs - or since the are made for biAmping, I could feed the Bass Modules with the Carver and feed the upper boxes with the Jolida tube amp).