Model 19"s

[Jim Easley]

Yes, all Model 19's came with Tangerine phase plugs. The 1.2K crossover is due to the 811B horn design. The lower usable frequency limit for the 811 is around 800 hz.

[Charles Chance]

I too, have been a bit puzzled by the 1.2K crossover. When the 811B was used with the A7, wasn't it crossed at 800Hz? Is the 1.2K better for "home use", maybe?

[DavidH]

Howdy....I just got a nice pair of model 19's
Did all of these have the tangerine hf driver? I saw some specs that showed an 802g
and another that had 902's, was that with different year models? Are there any mods that are common? I'm also curious about the
1200hz crossover, most horns seem to use either 500 or 800 hz. They sound great, I would like to hear other owners thoughts.
Thanks
David

[Jim D]

The word I heard for the 1200Hz xover was that the woofer and the 811 had similar Q (directionality index) at 1200hz. This was done at the time that ALTEC was researching horn and woofer directionality in great detail. They went with this crossover frequency in the MI lines which was also for driver protection. As for 800 Hz in the other speakers, 800 Hz is the junior crossover frequency for movie theatres, 500Hz being the senior. Acoustical studies showed vocal intelligibility needed good detail from 800 to 2000 Hz. This is why theatres use a minimum 800 crossover. In PA use 800 tends to punch a little better than 500. 500 is the center of the powerband in voice, which is why it was chosen for larger systems. The name Voice of the Theatre, really means what it says. JIm

[David Deratany]

If one is going to crossover at 1200 hz, will he see any benefit from using a 511 instead of an 811? Are there different considerations for home vs. theater use?

Happy Everything to all. This is a wonderful board.

[Steve Burger]

What is the size of the room being considered. This might clarify it more in terms of whether the 511 would be a better choice. My guess on the response you will receive is that at the higher level of frequency cut-off it is less of an issue whether to go with a 511 or an 811.

[David Deratany]

The room is about 13 x 21. I'm inclined to go with the 511's and at 500 hz unless there is a reason why I might want to use 811's at 800.

[TonyBlues]

I don't see why one would want to sway from the 1200hz crossover in the 19. Part of the reason I purchased a pair was to try a speaker with controlled directionality. There's a paper on this site that shows that at 1200hz the 416's dispersion matches that of the 811 horn. Both Altec and JBL were doing crossovers based on research along the lines of constant directivity large format monitors (JBLs Biradial, Altec Mantaray). I think this is why these speakers have the imaging and presense they do.

Back to Dave's question, the horns ring like giant cowbells. They need to be damped with silicone, RTV, tar, whatever ... (pay special attention to the gaps in the fins). Next, doublecheck the push connectors on the drivers and bottom of cabinet. They don't seem to hold up well. Also check the crossover controls for deadspots.

[TonyBlues]

Yep, the outside.

If you tap a screwdriver handle against the front of the horn it will literally ring for several seconds. Now pinch one of the fins with your fingers and tap again while holding the fin. Notice the ring dies sooner. There is a gap where the fins meet, try to fill it with black RTV like used for automotive gaskets. Try coating the outside of the horn in front of the mounting flange with a couple of layers. You can start with the bottom side if you don't want it to show. Tap the horn again. Try tapping it while putting your hand on different parts of the outside and see where some damping would work best.

At this point it's obvious that your dealing with something that it doesn't take a golden ear too improve on. Once you get the horn as dead as you like you can reinstall it and it should sound much clearer at louder levels. Less congested as they say.

There were several threads on the Audio Asylum site discussing the Model 19 and ways of damping the horn with different materials. Search for Altec, it should provide hours of amusement.

I would stay away from doing anything to the inside. I'm not sure what improvement could be netted there. But feel free to experiment, if you learn anything let me know.

[DavidH]

Hi..When you say damped, do you mean coat the
outer surface of the horn just to the throat??
Thanks
Dave