Upgrading model 19

[speakerdave]

Do you know if they changed the 1" horns?

It was not aquaplas but plain old silicone.

Also the foam inserts don't change the sound, but rather seems to impart better imaging.

[John]

Do you know if they changed the 1" horns?

I know they left the weld's out between the inner fins and did the silicone thing but that's about it.

My pair of 19's are from 1979 and have alnico motors with no silicone on the horns. And I have seen about half a dozen later pairs of ceramic motor 19's from the tail end of 19 producton and only one pair had the silicone on the horns. The owner was original to the pair and claimed that is how he bought them in the early 80's from the dealer. there was no outer signs of any damping on the horns.

[Zilch]

take this on.

I have, and I'm ALL done with it now.

BMS 4550 + L-pad....

[rgwalker]

Also, about those bowties--I know some experimenters have tried them with Altec drivers and liked the combination, but I have not, and I do not know if it really works without changing the crossover. Take it as an off-hand remark made without caution.

I have 288C drivers mounted to EV HR60 horns running at 500 - 9K Hz and the effect is stunning with absolutely no flat spots, spikes, rattles or sympathetic resonance. The crossover is an upgraded Model 19 and aside from an added capacitor for a 9K tweeter the values are the same.

Bob Walker

[Russellc]

That may be, but Altec did not change its way of finishing its horns for no reason. The 511E is a large format horn, and so would be expected to have to handle more power. I do not know if they ever issued aquaplased 1" 511b's and 811b's. Certainly when they are bolted to a bafffle or other mount they ring less, but they still have a resonance, which many people have discerned and found it worth their while to resolve.

in the end Altec switched to nonmetal composite mantaray horns.

I dont know about Aqua plas, but I have had two distinctly different Altec 511B horns. One type, the "fins" are solid metal and way back in the throat there is a little piece that connects the top of the horn to the bottom. On the later horns, they look identical, but the fins arent solid, they are seperate and a "rubbery" stuff in between the two pieces. Also, the little piece back in the throat isnt there. In the first photo, you can see the bosses where the piece would have gone. If you see it in person, you can tell there has never been one, only the bosses. On the second pic, of this old beater 511B, you can see the center piece back in the throat.

Russellc

[Russellc]

I know they left the weld's out between the inner fins and did the silicone thing but that's about it.

My pair of 19's are from 1979 and have alnico motors with no silicone on the horns. And I have seen about half a dozen later pairs of ceramic motor 19's from the tail end of 19 producton and only one pair had the silicone on the horns. The owner was original to the pair and claimed that is how he bought them in the early 80's from the dealer. there was no outer signs of any damping on the horns.

They also deleted the metal piece way back in the throat that connects the inside top to the inside bottom. I have frequently heard of people knocking this piece out on the older horns.

Russellc

[vintage-chile]

Hi Guys ,

IMHO a JBL H series horn is far better sounding than any Altec horn , on a small music room. Altec is harsh and stressing for my ears , sorry folks .
I recommended Joaquin to do so , the only secret here is to make a good attachement to the H91 horn.
I have listened and done such combinations a lot of times. Had a lot of JBL and Altec gear to do so. Maybe someone remember my vintage auctions at Ebay.

Greetings from Chile