Valencia To Onken Project Article

**voice of the theater** · December 4th, 2011, 12:26 PM

Originally Posted by GM

This is what I knew an Iconic to be until you or someone else here noted it on a Valencia label [824]: http://www.hifilit.com/hifilit/Altec/1957-j.jpg

GM

Wow! I've never seen that early (1957) Iconic speaker before. A totally different animal with a 412 biflex woofer and a 3,000 hz crossover. I'd love to hear one of those.....

**mah** · December 4th, 2011, 06:19 PM

Pano, thanks for the translations. Lots of interesting information including the take on speaker mounting. Unfortunately nothing on the principle of operation. I recall reading that the Onken enclosure acts like an aperiodic enclosure, a la Jordan.

http://diyaudioprojects.com/Technica...erformance.pdf

**Panomaniac** · December 4th, 2011, 06:38 PM

Actually in later articles for the Altec 414-8B and the Focal 10" woofer they discuss the Onken being a perfect 4th order bass-reflex. So the same tuning can be used (IMO). Much more math in the later articles. The hard part is figuring out the length of the ports, as they are slot ports and need a correction factor different from tube or flat ports. I have yet to figure out that part.

**Nipper** · December 4th, 2011, 11:46 PM

I have to ask.....

What makes these Onkens so different from the Altec 817 cabinets?

**Panomaniac** · December 4th, 2011, 11:51 PM

Good question. How long are the vents in the 817 cab? Are they deep slots like the Onken? Also the Onken uses near the same surface area for the vents as the woofer cone area. The 817 looks similar, is it?

**Nipper** · December 5th, 2011, 02:07 AM

Originally Posted by Panomaniac

Good question. How long are the vents in the 817 cab? Are they deep slots like the Onken? Also the Onken uses near the same surface area for the vents as the woofer cone area. The 817 looks similar, is it?

I don't have any specifics on the build but the concept sure looks the same to me....

**cradeldorf** · December 5th, 2011, 02:22 AM

Originally Posted by Nipper

I don't have any specifics on the build but the concept sure looks the same to me....

I bet that thing powers itself all around the room with those wheels on it.

**Panomaniac** · December 5th, 2011, 11:44 AM

Thanks for the pic. Yes, looks very similar indeed. I think the slots are wider than the Onken, but I don't know if that makes much difference. The horn loading would make a difference, of course.
All this dates back to the Jensen Utraflex, the father of both designs.

Here's a fellow in Italy who has Onken/817s
http://www.audiofaidate.org/forum/viewtopic.php?t=2616