View Full Version : Altec 811B vs 511B?

Doc Mark
09-10-2008, 07:38 AM
Hello, Friends,

I posted this same basic note in another thread, but thought maybe I'd better make it a "stand-alone", and so maybe get more comments on my questions. To those that have already seen this, in the other thread, my apologies, and thanks for your patience!

I have two pairs of Altec horns, one each of the 811B and the 511B, and I've always wondered what the big difference between them is, besides the fact that one can supposedly be crossed over lower? In most of my older Altec information, Altec actually crossed over both of these horns at around 1200 HZ. I've not used the 511B's for anything since I got them, many years ago, but have used the 811B's in medium sized PA cabinets, and like them, quite a lot, actually. Has anyone actually used the 511B's crossed over at 500HZ, and is so, how do they work in that mode? Thanks, very much, for any thoughts, or comments on the performance of these two horns. I'm thinking about getting rid of one pair, and keeping one, "for a rainy day", and need to decide whether it's the 811's, or the 511's, that will hit the bricks..... or, should I just keep both of them, as I have all these years, just for grins??!! ;);):D Take care, and God Bless!

Every Good Wish,

09-10-2008, 08:06 AM
Hi Doc,
You may find these measurements useful, so throwing them into the hopper:
Zilch did those using my 902 on 811 and 511.

Doc Mark
09-10-2008, 08:29 AM
Hi, Skywave-Rider,

Thanks, very much! That's very interesting stuff, and I appreciate your having sent it along to me. As to the Altec horns ringing, I never noticed that when I actually used the 811B's. I would think that, if they were mounted properly and tightly to an enclosure, that should dampen the ringing, at least somewhat, eh? Also, In the "old days", do remember having seen such horns with some sort of black "dap" applied to their outside surfaces. I realize, now, that this, too, was probably an effort to dampen any ringing coming from the horns. I guess that, someday, I'll have to play with them, and with the Altec drivers that I still own, and see how I think they sound to my old, tired ears. Fun! Back when I got my first nice PA system, I also used it for my stereo, between gigs! It consisted of Altec 816 cabinets, with JBL D130's, and the 811B horns up top, connected to 806A drivers, IIRC. I thought that system smoked any regular home stereo speaker system I'd heard to that time, except the L300's, for which I had deep lust, back then. Now, I have my own L300's, and a lifetime dream has been satisfied!! I'll have to compare them to those old Altecs, someday, though I don't have the 816 cabinets anymore, unforunately. Thanks, again, and God Bless!

Every Good Wish,

Tom Brennan
09-10-2008, 10:02 AM
I've used the 511 crossed at 500hz many times with various types of crossovers and slopes and with various Altec and JBL drivers. I even used them crossed at 500 1st order with no problems in home use with Altec 802 drivers but JBL 2420s used on the 511 crossed at 500hz 1st order "clacked".

Crossing higher, 800 or 1200, I hear no difference between 511s and 811s.

If you're worried about the horns ringing putting some non hardening modeling clay in the lips deadens the horns. You can also do what Altec did on later 511s where they didn't weld the joints in the vanes but instead filled the gap with some kind of rubber. If you have the 511s with the welded vanes cut through the welds with a sawzall and fill the kerfs with silicone or rubber.

IMO for home use there's no better sounding 1" horns than the 511 and 811. If I were to go to one pair I'd keep the 511s as they are more versatile and look cooler.

09-10-2008, 10:13 AM
I've use 511 horns in boxes for decades and never noticed any ringing.
However, I recently purchased a single 811 horn for a center channel in a 7.1 HT and it rings so much I removed it and replaced it with a plastic horn.

The 811 was used without a cabinet so perhaps that is the difference.

Doc Mark
09-10-2008, 10:38 AM
Hi, Tom and Robert,

Your comments were really what I was seeking. I wanted to hear from those that actually have used, or still use, those Altec horns, and I very much appreciate your comments!

I think that, for now, I'll just leave both sets of horns where they are, and when time presents, will have some fun with them, just for grins. Back when I used the 816 cabinets, and 811 horns, for home stereo, I was amazed at how "live" my music seemed! The dynamic capability of that horn-loaded system was simply amazing! And, to top if off, I was driving it with a crumby old, (Quadraphonic!!) Sansui receiver that put out about 15 WPC, IIRC! Listening to my favorite horn bands of the time, Chicago; Blood, Sweat, and Tears; Tower of Power, Cold Blood; and Average White Band, et.al., I LOVED the sound of that setup, as did anyone else that heard it! Now, remember, I was a young musician, and didn't know beans about much. Now, I'm old and though I still don't know beans about much, I do know what I like (L300's, and other great JBL and Altec systems)!! Fun! Thanks, again, Guys. Much appreciated, and God Bless!

Every Good Wish,

Tom Brennan
09-10-2008, 11:34 AM
The 811 was used without a cabinet so perhaps that is the difference.

Probably, the 811s in my Model 19s don't vibrate at all. Note that Altec always used the 811 bolted to a baffle or to a sled kind'a deal, always at least the bottom bolted.

The Emilars I use in one of my rigs are very heavy one piece castings yet even they ring a little when freestanding and not bolted to something, I had to add some modeling clay to calm them down.

Tom Brennan
09-10-2008, 11:35 AM
Have fun Doc.

07-07-2016, 10:02 AM
This thread comes pretty high when googling so I thought maybe I add the Altec specs.72517

Altec recommended lowest crossover freqencies, 511B at 500 Hz and 811B at 800 Hz.