Ever think of building a Cornu Spiral horn? Now you can!

[planet10]

Originally Posted by xrk971

OK folks, I have been doing some studying of horn theory using MJK's nice papers.

One thing i haven't seen you consider is that:

at the air cavity cutoff frequency, the distance the back wave has to travel down the horn and out to your ear should be (2n+1)/2 (n = o or any positive integer)* wavelengths of cutoff frequency further than the direct travel from the front of the cone to your ear.

*(odd number of half wavelengths)

In other words an approriate upper cutoff has a limited number of discreet values.

dave

[xrk971]

I think George mentioned this in one of the earlier posts. This is to prevent cancellation of the back and front wave right? When you say air chamber cutoff do you mean the higher freq cutoff based on chamber volume and throat area?

[planet10]

Yes. Yes.

dave

[planet10]

Yes. Yes.

dave

[prezden]

Your handmade textured paper looks great on the Cornu's. Where do you buy it or do you make the paper yourself? What amp are you using to drive the 16 inchers?

I buy the paper from a local specialty shop. Unfortunately it only comes in 20x28" sheets so a bit limiting in size.
Right now I am using an ODAC, JLM 06 pre and a 2024 amp. I'm hoping to make a gainclone for them in the future.

cheers

[xrk971]

Prezden,
One other question. Are your electronics (pre and power amp) housed in thos little pine boxes on the lower right? At first I thought they were just keepsake boxes but noticed knobs and toggle switches on the front, Very earthy in keeping with the hand made paper baffles! Nice.

[prezden]

Are your electronics (pre and power amp) housed in thos little pine boxes on the lower right?

Yes they are. I get to combine 2 hobbies in one

[Cal Weldon]

Since I can't really help myself I stopped in at not one but two different Sally Ann's.

What I found at the 1st resembles the LG in appearance but they are a little light in the top end. Made by JVC in China they were solo in small ported boxes. They have a stronger bass but not good as a tweeter. Kinda half way between the Fostex 125's and the LG's. On axis they are fine but fade quickly off axis.

[Cal Weldon]

Since I pulled the LG's here they are. Superb vocals and up.

[Cal Weldon]

This is the other 'discovery' that I would like to try in a little Cornu. It's the first driver I have known that has to be back mounted. The 3rd pic shows why.