View Full Version : Altec 511B horn

Steve Racey
11-15-2006, 03:53 PM

What Altec drivers where designed for this horn? As Altec drivers are becoming scarce, what current JBL drivers would you recommend for this horn?

The horns currently have 1 3/8 screw on adaptor plates fitted with E/V 1829 drivers, limited in thier frequency and power range



Tom Brennan
11-15-2006, 04:02 PM
The 1" throat 800 and 900 series drivers fit on the 511. They are not scarce and GPA makes brand new "Altec" 902s, I just bought a pair. The picture is one of my new GPA 902-16s used in 1961 Heathkit AS-21s with Altec 811 horn and 414 woofers.

JBL 2420, 2410, 2426 etc 1" drivers will work fine on 511s if you redrill the 511's flange to the JBL 3 hole bolt pattern. I've used 2420s and 2410s on 511s. Shown is a 2420 I put on a 511.

11-15-2006, 06:15 PM
You should be able to find a peir of altec drivers with another set of horns hanging on them for what you' get the JBL's for. AS for the EV's they have a simple passive EQ circuit on their websightfor the highs. I've got EV horns and drivers, had altec 800 .night and day the altecs were sort of a tweeter these carry the load and I bought a pair of pyramid Tw67 looks like an 075 on steroids so far I love it wow brings out stuff that an equalizer cant get out of the horns. Haven't had it long. Can't guarantee I won't get tired of it but I sure like it now

11-15-2006, 06:27 PM
How do you like those 902-16B's Mr. Brennan? I thought about upgrading my Carmel's with the same drivers. I would need to sell the original 802's to help offset the cost of them. Was it a worthwhile upgrade? I assume they have the Tangerine phasing plug.

Tom Brennan
11-15-2006, 06:50 PM
Mark---I didn't really hear any difference. Note though that I'm 57 years old and if the 902s have better highs I might not be hearing it anyway.

I changed out the old 804s last night and a little while later swapped out my Jolida amp for my old Fisher 500B which was just gone over by Terry Dewick in Knoxville. Now THAT made a big difference, the Fisher sounds MUCH better than the Jolida, much better clarity. So the 804-902 thing has been kind'a swamped.

In any event I'm happy.

Kind Regards

11-15-2006, 07:57 PM
I can't hear any difference between 800s and 900s (given equivalent 'frams/horns), as long as I cross them at 800 or better. Go to 500 though, I'd have to pick the AlNiCos. Nothing a little shelving won't cure for either one. I've got enough of both to last me, but at the current market if I were buying I'd buy new for sure.

Just pick a bolt-on model from those suggested Steve, and lose the threaded adapter.....literally.

11-16-2006, 02:24 PM
I can't hear any difference between 800s and 900s (given equivalent 'frams/horns), as long as I cross them at 800 or better. Go to 500 though, I'd have to pick the AlNiCos. Nothing a little shelving won't cure for either one. I've got enough of both to last me, but at the current market if I were buying I'd buy new for sure.

Just pick a bolt-on model from those suggested Steve, and lose the threaded adapter.....literally.

Hey Moldy, would you recommend I try the new 902-8 driver for the 9846 project I am doing or stick with the 802-8g's?

Mike Caldwell
11-16-2006, 03:52 PM
If you want to go with JBL drivers look some JBL 2425 one inch drivers. They are drilled and tapped for both three bolt and two bolt mounting and fairly easy to come by. I have re drilled horn flanges on some B&C horns for three bolt drivers, I used a 2327 one inch to two inch throat adapter for the three hole pattern. That made it easy to get the holes correct for proper throat alignment by looking through it to line up the throats. Any one inch horn would work for a pattern.

Mike Caldwell

11-17-2006, 01:48 AM
Hey Moldy, would you recommend I try the new 902-8 driver for the 9846 project I am doing or stick with the 802-8g's?

I guess that's not OT since it's about drivers for 511s, but let me take the liberty of giving 2 replies;

Yes, I recommend you try the new 902s (18,000 gauss). If you play loud, go Pascalite, otherwise AL.

For the 9846s w/stock XO and 511s, recharged or equiv. 802G/808B (15,250 gauss). Steeper active filters could be "better", everything considered. If you already have 802s, it's a no-brainer to at least try 'em first.

Keep in mind the additional network for the 9846 further flattens and extends HF (hint for all; the series R and bypass cap from the 9846 network circuit works to shelve 800s or 900s nicely, about anywhere).

What I get with 900s on 511s (below) pretty well looks like it should on RTA, with 500Hz not being a particularly pretty place to add a 12dB rolloff.

If you weren't around then, (many of us weren't...), 900s hit the streets about the same time most all the Pro, MI, and PA systems went to 800/1200Hz XO. For most >800Hz XO apps, they shine. I've played them on several smaller CD horns too, (personal preference), for >1200Hz in a limited space, you can easily EQ them to alienate all the dogs in the 'hood.

Steve Racey
11-17-2006, 05:36 PM
Thanks for all the info everyone! I am new at this.

I currently have found two JBL 2225h woofers in 4 cubic ft boxes. The orginal horns was missing and while these boxes appeared tuned for the driver I am considering closing up the horn cutout and using a pair of 511b's that I have had for some time now. For example the JBL specs for there JBL46710k speaker system crosses over at 800 HZ with a 2426J driver and the JBL4673 crosses over at 500 HZ with a 2445J driver. I got these spec sheets from a friend at IMAX Mississauga.

In order to keep the cost down a bit I am trying to find a resonable match to these woofers using the old Alec horns.

Will the newer Altec 288-8L drivers keep up with the 2225H? What is the power handling capibility of the 228- 8L

Again, thanks for all the help

Steve Racey,

( The Frogman)

11-17-2006, 08:07 PM
It depends on the crossover point and horn, but you will not exceed the power handling capacity of the 288-8L (for home hi fi) unless you are planning on listening from a couple of streets over. However, that is a 1.4" exit driver and will not mount on the 511b horn.


11-18-2006, 08:03 AM
No worries for any compression driver mounted to a 511B keeping up with a 2225. Any combination (barring physical mounting issues) would render a very high effeciency combination compared to any woofer in a box.

FWIW I have used Altec 806/802 drivers with good results on this horn. However my favourite was a JBL LE175 after drilling extra holes in he 511. It had a very seductive, big, warm sound. No doubt a 2420/LE85 would be nice too. My horns also had automobile undercoating to hep dampen the ringing.


08-13-2015, 12:13 PM
I have a similar issue. I have recently changed from a 511B horn driven by an 802-8D paired up with the N-800-F (because when I first designed/built these last march 2015 I did it with the 811B's) and thought I would simply leave well enough alone. But now...I went from 811B's to 511B's (barely fit) to an external 1004B hanging from the ceiling on chains driven by a pair of nice 288's.
Now my question, I really need to reconsider my "leave well enough alone" statement...huh?
I have, or more correctly I'm soon to be removing the 511's from the cabinet completely (the horn/drivers are in the cabs but disconnected) and replace the baffle face with a new 2-holer!
Yes a pair of 416-8a's in each cabinet! with monstrous 1004B horns looming over my tiny (36inT X 33inW X 26inD) little cabinets...I say that jokingly because they still seem to dwarf my cabs, go big or go home, is what a friend of mine says...too often. Do I absolutely need a 500Hz crossover???? To be all that I can be?
Thank you and I truly respect opinions and constructive criticism.

10-23-2015, 11:50 PM
Hi bruno13, I ran across your post to this old thread while googling 511b and was taken by your choice of drivers and your hanging horn! Years ago I built my speakers to flank my fireplace. I have included a photo of the right side. Note the hanging horn. At the bottom is a Lafayette enclosure I assembled around 40 years ago, still in great shape and still housing an Altec 421A bass driver. The enclosure over the window at first housed an EV 8HD with EV driver and an EV tweeter horn (T350). When I got a second 511b (I had one for years with an 808-8A driver and matching xover) I realized during a test that the diaphragms on the EV horn drivers and my 808-8A had seen better days. I got a pair of Peavey drivers with adapters, fitted them to the 511s and replaced the 8HDs with them, hanging them with chains since the boxes were too small to fit. The EV tweeters have had a number of replacements, the latest and best being a pair of Eminence biradials, now the only occupants of the overhanging boxes. However, those boxes (along with trim moldings) made fine anchor points for hanging the 511s, and they've been dangling there for about 20 years now.


I did write to comment on crossovers, since you had asked about them. The system whose right channel is pictured was predicated on a triamp layout with a homemade 3-way 3rd-order Butterworth active xover based on a design given in the wonderful old NSC Audio/Radio Handbook. With the EV mid horns it crossed over at 750hz and 4khz. After installing the 511s I modified it to 450hz/4khz (I figured the low power levels and added slope would give me margin, and 20 years later it all still loafs along). So the difference, in my opinion, between an 800hz xover and 500hz is immense. I would have been wasting a great asset crossing the 511s at 800hz. And you have a 1004 now? Further, I believe the contest between passive and active crossovers is a no-brainer in terms of both quality and flexibility. No need anymore to spend nights soldering opamps, caps etc. Cheap and good commerically-available 24db/oct active analog xovers abound and can be dial-tuned (as in no more component replacement for different xover points).

But there's way more. Not long ago I began a new project in my garage where I spend great amounts of time. It's big, so it affords me a great space to fill with sound. There the woofers are 421-8H, the mids University Cobreflex (peripherally Altec-related at least), the mid-hi's are the old EV 8HDs which I dug out (they won the contest), and the tweeters are small Eminence CD horns. It's all subject to change; it's my hobby shop, free of constraints of decor etc. But 4-way? Too much, right? Here's the rub: I can do it effectively because I'm now kit-building DSPs and class-D amplifiers. I can cross over around 350hz (the Cobreflexes handle it without waveform distortion, a little rolloff) at a once-unheard-of 192 db/oct, and then at 3khz and 6khz, each at 512db/oct (!), all using phase-linear FIR filtering, fully laptop-programmable! The transitions are essentially seamless. So may I suggest you look into active digital xovers/EQs (they generally cohabit the same DSP). The results are better than the wildest dream of any hi-fi fan of not long ago, and such things are suddenly absurdly affordable if you search. I think your 2-way system deserves no less, and you could come up with a premade DSP that has both IIR and FIR filtering for very short money and previously unimagined performance (plus so small it might go unnoticed). Takes a little research but less than you'd think. Five months ago I knew nothing about it. You don't need to do room-correction (though you could) to reap the benefits of a DSP.

Anyway, there are two of us at least with horns of Damocles! :)