Front horn for JBL 2118J

[Summer Rain]

I'm new to the Lansing Heritage site. I though I would share my latest DIY project. It's a front horn for my Summer Rain project.
It uses the JBL 2118J and the horn is my design using 3D CAD. The high frequency is coaxial inside the horn. The compression driver sits directly in front of the JBL 8". compression driver is only 2" outside diameter, so it acts as a phase plug for the 8".






I had steel templates CNC plasma cut to use as templates to cut out my pieces. I did this because I'm not very good with layout. History shows that I will certainly screw up a dimension and scrap my expensive baltic birch. This saves time as well.

This is as far as I've gotten as of last night. I will continue to post my progress.

Comments are welcome. My JBL 2118J is a 16 ohm version. The LF and HF are 8 ohm. I'm thinking this will make some nasty impedance swings for the system when I'm done with the passive crossover. I'm thinking I should have the 2118J reconed to the 2118H 8 ohm version. Will this work or are the motors different?

[pos]

Nice looking project!
What HF unit are you using?

[Summer Rain]

I'm using the B&C DE120. It's a neo magnet driver with polymide diaphragm. It sounds very nice. Using from 2 kHz up. My brother uses the Altec 808-8a with GPA diaphragms. The DE120 is on par.

[Summer Rain]

I should mention that the bass cabinets are completed already.

[grumpy]

Looks to be well finished and an interesting way of integrating the
various components Sort of a modern 'Euro' architectural look (Swedish?).

I'm sure you've contemplated many things in the design of this system:
Sufficient clearance (2118 dome to compression driver)?
Vertical horn mounting option? In case the tweeter horn turned out
to act as a diffraction device in good way.

Will be interested to hear how it all goes when completed!

(and welcome)

[Summer Rain]

Looks to be well finished and an interesting way of integrating the
various components Sort of a modern 'Euro' architectural look (Swedish?).

I'm sure you've contemplated many things in the design of this system:
Sufficient clearance (2118 dome to compression driver)?
Vertical horn mounting option? In case the tweeter horn turned out
to act as a diffraction device in good way.

Will be interested to hear how it all goes when completed!

(and welcome)

Thanks for the comments. The visual look I was after is the TAD studio monitor for bass cabinet. The large mid horn is a throwback to the Western Electric era.


Yes it will be interesting to hear how it all comes together. I'm certainly taking a chance. Computer simulations and discussion can only be taken so far. Sometimes there is no replacement for physically building the thing and measuring/listening. The HF is certainly relying on diffraction for dispersion. Could be complete disaster, or be 80% there requiring some design changes. I've made sure that I can easily change the HF horn design if need be!
It will be an interesting learning experience, and I just might have some really good sounding speakers when it's all done.

[stephane RAME]

In the picture, there is one on each side:
-Western electric 22a horn
-LF Onken 360

Stéphane