• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Altec horns coming!

spaceman

spaceman

Registered Lunatic
Well, I probably should wait till tomorrow for this, since they're not in the house yet, but I'm 90% sure the seller is cool, so I'll jump the gun a little. I found these advertised locally, for a pretty decent price I think, though I'm hardly knowledgeable on their going price. Good old 811-B horns, with 808-8A drivers, in what looks like very good condition. :D I still need to read up a lot more, but these look like they should keep me happy for quite awhile. :yes: I read in another thread, that the diaphragms might want upgrading, and read briefly about having something done to the Alnico drivers, but that's all over my head right now, so those things are for the future, after more reading. Right now, the best woofers I have are my EVM-12Ls, which I haven't been using lately, but should work VERY well with the Altecs. Any suggestions for a proper value capacitor to use, on a temporary basis at least, until I find some nice crossovers? Thanx. Here are pics, of the actual horns.
 

Attachments

  • Altec1.jpg
    Altec1.jpg
    5.6 KB · Views: 95
  • Altec2.jpg
    Altec2.jpg
    4.4 KB · Views: 91
  • Altec3.jpg
    Altec3.jpg
    4.6 KB · Views: 111
Register to hide this ad
Hey, that makes it REAL easy, thanx much. :thmbsp: Since the 811-Bs go down to 800 Hz. (?), and the EVs hardly even need a HF driver, there should be a lot of room to experiment, once I get a better feel for things. I've talked with the seller again, & they'll be mine early tomorrow afternoon. :banana:
 
A good choice in crossovers, simply buy (from Parts Express) the Eminenece 2-way 800 hz crossovers and 100 w L-pads.
 
Just my .02 here, but EV 12L plays well up to 2k and beyond, unless you're driving them with low power SET's, i'd be crossing the 808/811 a lot higher than the 800hz cutoff of the 811 horn, probably something in the 1200-1500hz range.

If you're going to use a 1st order filter, the parts aren't that pricey so why not get parts to try a couple different XO points and let your ears be the judge?

Here's a 1st order calculator: http://www.carstereo.com/help/Articles.cfm?id=55#first

Just my .02 y'all understand....................
 
Zilch said:
Tom: Would this work as well with 808-8As as it does with 806As?

http://audiokarma.org/forums/showthread.php?p=1473345#post1473345
Click to expand...


Zilch---Supposedly the 808 with it's symbiotic diaphragm has less extended highs than the aluminum diaphragm models. However the 808 uses the big magnet of the 802 so it might have better extension than an 806 when used with an aluminum diaphragm.

I read something online by a fella who worked at Emilar who claimed that the reason the symbiotic diaphragms have less highs is because they have a thicker mounting ring and thus the diaphragm is farther from the plug than with the aluminums.

Next on my agenda is a mic, a new RTA and a pair of Emilar 175s.
 
I read something online by a fella who worked at Emilar who claimed that the reason the symbiotic diaphragms have less highs is because they have a thicker mounting ring and thus the diaphragm is farther from the plug than with the aluminums.
Click to expand...
Interesting, i remember reading something quite a while back, either on the altec board or LH, that Altec actually went to some lengths to engineer the HFE out of the symbiotik.

I've always wondered why they didn't use a phenolic phragm................

Would that have encroached on patents from other makers?

On a side note, i've found 802's and 808's both with paper shims between the mounting hub and driver face. Someone explained that the final testing of these drivers involved running a 500hz signal thru them at rated power, the driver had to work without the diaphragm contacting the phase plug, and shims were added to the assemblies that didn't initially pass, until they did indeed meet the above criteria. Again, not first hand knowledge, just parroting what i've read along my journey.
 
SpeakerLabFan said:
Wow, those look fantastic and it sounds like the house will be rocking. Congratulations.
Click to expand...

Thanx SLF, I've always wanted some nice horns, & seeing yours at the mini-meet helped fuel the lust, lol. ;) The more I look around the net, the more I think I got a pretty nice price on them, 3 benjamins, but I think it was pretty lucky just to find someone willing to sell them, especially with no shipping involved. It was just my pure dumb luck to be in the right place at the right time again. :D And thanx very much for the info, guys, this is definitely the place to learn right. :thmbsp: 3 1/2 hours & counting. ;)
 
bowtie427ss said:
Just my .02 here, but EV 12L plays well up to 2k and beyond, unless you're driving them with low power SET's, i'd be crossing the 808/811 a lot higher than the 800hz cutoff of the 811 horn, probably something in the 1200-1500hz range.
Click to expand...
The 811 horn certainly behaves better at 1200 Hz than 800 Hz. (511 is better at 800 Hz than 500 Hz, also.) Altec moved the crossover frequency for 811B horns to 1200 Hz in Model 19 and subsequent designs.

What several here have not yet noted from the work Steve O and I have done with 846 Valencia et.al. is that the crossovers are NOT symmetrical at 800 Hz. They were, initially, but Altec early on moved the HF highpass considerably higher to attenuate (somewhat) the excess midrange response of the compression drivers. See the actual response measurements with the 846 highpass in the post I linked to above, which shows the behavior of the 806A driver on 811B horn both with and without the 846 highpass filter. Note how it knocks down the output between 800 Hz (the ACOUSTIC crossover frequency) and 3.5 kHz:

attachment.php


The ELECTRICAL crossover frequency is NOT 800 Hz. If you use a symmetrical crossover (lowpass and highpass at 800 Hz) as suggested by others here, and as initially used by Altec, without additional HF compensation, you generate Altec upper midrange "Shout" in full measure. I don't believe it matters which motor or diaphragm is used, the phenomenon is characteristic of compression drivers themselves, generally, and you must employ compensation, either passively or actively, to achieve flat frequency response:

http://audioheritage.org/vbulletin/showthread.php?t=4410

It is SO characteristic, in fact, that most active crossovers and many pro amplifiers accordingly incorporate HF compensation (EQ) circuitry for use with compression drivers and horns. In the Behringer I have referenced in that link, you push a button to accomplish it. While it can also be implemented passively (Tom uses the Altec T-filter circuit, I noticed in one of his posts,) I'm suggesting that Spaceman invest the requisite few extra dollars ($130 PE list,) involved in going active biamped and securing control of his new 811Bs from the outset.... :yes:

Tom Brennan said:
Next on my agenda is a mic, a new RTA and a pair of Emilar 175s.
Click to expand...
Go, Tom, GO!!! :thmbsp:
 
Well, I can partially understand what you're saying, Zilch, and appreciate the advice. I think I'll go ahead and cross at 1200Hz as you suggest, for now, & see what happens. I've been pretty intrigued with the idea of bi-amping, too, but never really tried it. I know where there was a Sansui 7000 receiver for sale pretty recently, so I might have to try to snag it soon to match the one I have. I have a lot to learn yet, but remember reading that matching amps are best for bi-amping.
 
If you are vertically bi-amping, having matching amps isn't so important. If you have a different amp on your horns than your mids and or subs, you would never know it. Just use an amp that will carry the load you need, such as the amp on your sub will more than likely need to be more powerful than the one on the horns.

Now if you are bi-amping horizontally, such as each of your horns on a seperate amp, then yes, you need matching amps..

BTW.. NICE SCORE!.. .I'm still looking for a good pair of Altec horns, and it isn't an easy task..
 
spaceman said:
I have a lot to learn yet, but remember reading that matching amps are best for bi-amping.
Click to expand...
That depends upon how you split it. The power output requirements for the compression-driver HF are but a fraction of that required by the LF. If you use separate amps for HF vs. LF, then you can choose the type according to taste, and many tube fans use "mellower" tubes for the HF and SS for ballsy bass.

I use the very economical Sonic Impact T-amp for the biampped HF in my test system here. Remember that your compression drivers are extremely efficient. The T-amp's 12 Watts is enough to power a rock concert with them.... :yes:
 
Looks like I'm getting a better idea in my head now, of where I want to go. The reason I like my Sansui 7000 so much, is the "ballsy" bass it puts out, much nicer than the average ss amp. And I have a Fisher 800-C receiver, that will be getting serviced sometime soon, that should be excellent for the higher frequencies. I knew there was a reason for buying all this old junk, and it's starting to look like it'll come together nicely. :D BTW, thanx similost, & I'll send you some karma, if it'll help you find some too. :smoke:
 
Welp, they're here, and they look and sound beautiful! :banana: The seller had me pacing the floor a bit, as he came about 1 1/2 hours after the set time, lol, but he turned out to be just as cool as I thought he was. Turns out he's a guitar player, among other things, & has lots of other cool toys I might be interested in later. The only thing that keeps these from being in like new condition, is that one of the binding posts was slightly cross-threaded, and I straightened it out pretty easily, but scratched the paint a tiny bit on the driver. I've been using a Concept 5.5 receiver, with Genesis II cabs, with an ESS 8" Alnico woofer, so even though the speakers are crossed with just a 10 uF cap, that's what I'm still using for now. I just used a little more wire for the HF driver leads, & taped them, and the Altecs just barely fit on top. After I turned the treble down & the bass up on the Concept, I remembered that the Genesis' have a 2-position toggle attenuator, & once I switched that, it balanced things out really well. The ESSs are 4 Ohms, & that probably helped out too. Man oh man, do these things sound good. :D :music: :D
 
Paul C said:
A good choice in crossovers, simply buy (from Parts Express) the Eminenece 2-way 800 hz crossovers and 100 w L-pads.
Click to expand...

This is precisely what I did, I just ordered the dayton caps to replace the electrolytic caps the crossover came with. I am adding the compensation circuit as soon as the correct resistors arrive from PE. I use 416 8C or 5158G along with 802 8G on 511B. So far the crossover is an advantage over the original. Its hard to tell which helped most, the new caps, (no doubt) or the higher (800 vs 500) crossover frequency. More bass, more punch and more clarity at lower levels. will be interesting when my high frequency compensation parts arrive!

Russellc50
 
Yeah, I was thinking about the Eminince crossovers, but wouldn't you need to swap inductors as well as caps, to get to the 1200 Hz level? I'll be looking a lot closer soon here, no huge rush, especially on a holiday. Speaking of the New Year, my local classic rock station is doing that "top 1,000 songs" thing, so it's a pretty nice way to break these in to my system. As good as they sound, I can't stop thinking that they'll sound MUCH better, once I get the crossovers dialed in. :smoke: It never really occured to me before, but I'm going to have to really compare the EVs & ESSs against each other. They both sound very good, so it might take some time deciding which works better. :scratch2: BTW, Russelc, I'm kinda glad I got the 811s, size-wise, the 511s might have been TOO big, lol. ;)
 
I would seriously consider an active crossover, especially the new Behringer... you can do so much more with them and really tune the system to how you want, and change it on the fly to suit your taste..
 
You must log in or register to reply here.
Back
Top Bottom