Incoming...811b horns without vanes

[BillWojo]

Yea, they are modified 811b's that someone reworked. Listed on ebay for 59.99 each plus shipping. Seller is real close to me so I made an offer and he excepted. I'll pick them up tomorrow.
Seems there are different opinions as to how these sound, figure that I'll add them to my pile of stuff to play with. Looks like who ever did it did a decent job and didn't cut them in half to do it.
I'll try and post the ebay link.

BillWojo

Says item #2, there was a set of them, 2 different listings



Vintage Altec Lansing 811B Tweeter Horn Item 2 | eBay

[Phil-G]

They look good without the vanes. Who ever took them out did a nice job.

[Elitopus1]

Its supposed to be an improvement. I have never heard a pair of devaned 511 or 811 though. I know the 511 look just like Emilar EH500 without the vanes.

You'll have to give us your listening impressions on these Bill

[GM]

Improves the mids, mucks up the HF to my ears. Better overall to just remove the little vertical brace, cut the vane welds and use vibration damping inserts like Altec did near the end of the 511's production. Among other things, it takes the 'starch' [stress] out of it form welding. If any 811s were done, I don't recall learning out it.

IME tweaking these things, by far the most audible gains were had in matching [align honing] the driver/throat out to where this conical HF WG joins the square flare, replacing the cardboard gasket with a proper sheel metal one using wax paper or similar thin, yet ultra sealing, gasketing material [get it right and wheel bearing grease suffices], damping bell modes with the vane inserts and proper baffle mounting to load the driver lower as it was originally intended along with a foam mouth extension that's somewhat larger, deeper than the one developed for the M19 and later replaced fiberglass insulation on other models to quell the mouth's eigenmodes, which reflect back to the throat causing most of the 'ripple' one sees in all but the most smoothed response plot.

GM

[Elitopus1]

replacing the cardboard gasket with a proper sheel metal one using wax paper or similar thin, yet ultra sealing, gasketing material

OT: I'm curious what the benefit of this is. Does the cardboard gasket leave a little ridge (or void) in the the throat making it not smooth?

I had thought of using something different. Only because I have more drivers than gaskets. I was going to copy the cardboard one with my new gasket though. Someone had mentioned getting some gasket material meant for engines, where you can cut out the size and shape you want.
The sheetmetal gasket also interests me. I have access to many different thicknesses of sheet aluminum

Thanks again for sharing

[Old Guy]

I experimented with 511's , noticed the vocals "cleaned up". We eventually produced the 511 sans vanes in fiberglass.

[SD-50]

They look good without the vanes. Who ever took them out did a nice job.

Yep.

- - - Updated - - -

Improves the mids, mucks up the HF to my ears. Better overall to just remove the little vertical brace, cut the vane welds and use vibration damping inserts like Altec did near the end of the 511's production. Among other things, it takes the 'starch' [stress] out of it form welding. If any 811s were done, I don't recall learning out it.

IME tweaking these things, by far the most audible gains were had in matching [align honing] the driver/throat out to where this conical HF WG joins the square flare, replacing the cardboard gasket with a proper sheel metal one using wax paper or similar thin, yet ultra sealing, gasketing material [get it right and wheel bearing grease suffices], damping bell modes with the vane inserts and proper baffle mounting to load the driver lower as it was originally intended along with a foam mouth extension that's somewhat larger, deeper than the one developed for the M19 and later replaced fiberglass insulation on other models to quell the mouth's eigenmodes, which reflect back to the throat causing most of the 'ripple' one sees in all but the most smoothed response plot.

GM

I did the honing, wax paper gasket, removing the vertical inserts in the throat, and damping, All of these tweaks provide audible sonic gains.

[Elitopus1]

Are you guys using a single layer of wax paper or multiple layers?

[SD-50]

Are you guys using a single layer of wax paper or multiple layers?

I use a single thin layer, but thinking about trying several layers, or a single thick one.

[Elitopus1]

I use a single thin layer, but thinking about trying several layers, or a single thick one.

Ok thanks. Looking at my 802D and Emilar EH800 horns they both look pretty flat on the mating surface. It does make sense that I wouldn't have to use a thick cardboard gasket.

I looked in the horn throat and with the cardboard gasket you can see a big gap between the horn and driver. With a thinner gasket or none there is no gap at all.