Multiple horns vs. multiple LF drivers

[Steve56]

I think you are on a good path with your plans. A single horn with the newly reconed 416s will yield great results. Your primary concern is going to be building a good crossover network. I'm sure others will chime in with recommendations, but the one addition that I made to my crossover that made the most improvement was the incorporation of the Altec 30923 horn eq/attenuation network. This simple network (three resistors and one capacitor) is inserted between the hi frequency output of the crossover and the compression driver, and removes about 6-8 decibels of the mid-frequency peak that makes the 802 (and most other drivers of the era) sound "honky." The difference is literally day and night.

If you decide to build one of the "Z-19" crossover variants, you will not need the 30923, as an adjustable version of it is part of the crossover.

Finally, I've used POR-15 on various auto restoration projects since the late 1970s. It's a great product. But I don't think it will produce one ounce of damping for the horn. This is because POR-15 produces a relatively thin coating that is rock-hard and almost becomes part of the horn itself. It will make the horn casting a little bit thicker, for sure, but I'm quite sure that the only result is that the horn will simply ring at a different frequency - but it will still ring.

Others will likely add to the thoughts on this subject, but my personal experience with using the 802/511 combo in a home speaker system leads me to believe that the ringing is simply not an issue worth devoting much time or money. Just make sure that the horn is solidly mounted in the cabinet and you will be home free.

GeeDeeEmm

Hello GDEmm,

I am planning on building the crossovers using the Z-19 crossover. I found 2 drawings, but the resistors have different values or one is a mistake. In one the values are 2,3 and 4 Ohms and in the other they are 20, 30 and 40 Ohms? Is one a mistake? Also, what is the crossover point? 1200 Hz? Thank you.

[Don C]

I think that the character in the upper drawing is the letter O and not the number 0.

[Steve56]

I think that the character in the upper drawing is the letter O and not the number 0.

I think you are correct. I didn't think of that and I found a few more parts lists that had 2,3 and 4 instead of 20, 30 and 40. Thank you for helping.

[Steve56]

My memory is not what it used to be. I thought I had bought 2 pairs of HF drivers a "few" years ago for my long term project of building a set of model 19's. I forgot where I put them and after 2 weeks of looking I found one set of 806-8As (Not even remotely close to where I had stored them). I thought I had another set of 900 series, but have not found them yet. The label on the box indicated I had bought the 806s more than 8 years ago. Anyway, I just ran across a set of 802-8Gs and bought those. When I opened them up, I found 2 different diaphragms, one having a "909" emblem on it and the other blank. There was some white powder on the "909" diaphragm and the other is clean.

I bought a Kirby vacuum cleaner from goodwill a long time ago. The body was thick aluminum with a lot of corrosion. I remember I had to sand it all off before polishing it back to shiny finish. The powder on the diaphragm looks similar and when I tried to get it off with alcohol and a swab, there were some rough areas left.

Bill at GPA suggested I try them and if they work, go with it. I'm worried that once corrosion starts, it keeps going and I don't think grinding and buffing is an option. Also maybe better to swap out the "909" for an original as Bill said it was made for high power and I don't need that for my living room. Better to have 2 matching diaphragms? I probably would not hear the difference I'm guessing. Also, I don't have any way of testing them before I build the cabinets and crossovers.