Fraltecstein

**Vathek** · December 28th, 2007, 01:29 PM

Hi everybody

this is my first post here and I'm afraid I have more than just one question.

I just acquired some real funky A7's, or rather this fraltecstein out of which I hope to build a pair of A7's.

The bass-cabinets are two 828 or 825 made out of chipboard, but quite well done actually, although mostly unbraced. But they look like a decent starting point and are fine for the time being. Mounted in them are 421-8LF's that at one point have been reconed to 416 or 515(?), because they don't have the aluminum dustcap but the altec typical vented cap.

Then there are five 511b-horns and one 811b. For drivers there are two 808-8b and one 808-8a, all with different diaphrams.
The strangest thing though are one 288-8k and one 292-8a bolted onto two of the 511b that have been modified for those drivers to fit. Meaning one mounting-hole has been enlarged and two more drilled. And the entry to the horn has been enlarged to the 1.4" of the larger drivers using a rasp or something similar. Both the larger drivers seem to have their original diaphrams in them.

There are also four crossovers from 937-speakers, two of them were wired in parallel per speaker! These are definitely not going to get used.

Sorry for this lenghty list of strange altec findings, but I think it might help regarding my questions:

I intend to use the speakers only at home for hifi/home-cinema use but I like to crank things forums

So:

1. The 808-8a has a 20275 diaphram in it and sounds fine, I'll leave that alone. One 808-8b has a working symbiotik, the other a blown aluminum, I want to replace both with new ones from GPA. I know this has been discussed a million times but I'm leaning towards pascalites since I will bi-amp the speakers and this would leave me more headroom to use EQ which in the end might give me more top end than aluminum diaphrams. Or is this logic flawed?

2. What to do with the larger drivers? The 292-8a is of no real use to me, since I want to stay 2-way and I need neither the power handling nor the low cut-off frequency. With the 288-8k I'm unsure what to do. It sounds fine to me in this modified 511b but I have nothing to compare it to and before I start looking for a second one, I'd appreciate any input on whether this makes any sense at all, since the sound still has to travel through the 1" horn even though it's been widened to 1.4" at the entry. And does a 288-8k driver have any sonic advantage over a 808-8b with alum phram from say 700Hz up? (I don't like to cross too close to a horn's cutoff frequency)

I'm sure there will be many more questions in the future, but for now any help just to get fraltecstein to sing its first notes would be greatly appreciated.

Thanks, David

**speakerdave** · December 28th, 2007, 03:42 PM

Originally posted by Vathek:
Hi everybody

this is my first post here and I'm afraid I have more than just one question.

I just acquired some real funky A7's, or rather this fraltecstein out of which I hope to build a pair of A7's.

The bass-cabinets are two 828 or 825 made out of chipboard, but quite well done actually, although mostly unbraced. But they look like a decent starting point and are fine for the time being. Mounted in them are 421-8LF's that at one point have been reconed to 416 or 515(?), because they don't have the aluminum dustcap but the altec typical vented cap.

Then there are five 511b-horns and one 811b. For drivers there are two 808-8b and one 808-8a, all with different diaphrams.
The strangest thing though are one 288-8k and one 292-8a bolted onto two of the 511b that have been modified for those drivers to fit. Meaning one mounting-hole has been enlarged and two more drilled. And the entry to the horn has been enlarged to the 1.4" of the larger drivers using a rasp or something similar. Both the larger drivers seem to have their original diaphrams in them.

There are also four crossovers from 937-speakers, two of them were wired in parallel per speaker! These are definitely not going to get used.

Sorry for this lenghty list of strange altec findings, but I think it might help regarding my questions:

I intend to use the speakers only at home for hifi/home-cinema use but I like to crank things So:

1. The 808-8a has a 20275 diaphram in it and sounds fine, I'll leave that alone. One 808-8b has a working symbiotik, the other a blown aluminum, I want to replace both with new ones from GPA. I know this has been discussed a million times but I'm leaning towards pascalites since I will bi-amp the speakers and this would leave me more headroom to use EQ which in the end might give me more top end than aluminum diaphrams. Or is this logic flawed?

2. What to do with the larger drivers? The 292-8a is of no real use to me, since I want to stay 2-way and I need neither the power handling nor the low cut-off frequency. With the 288-8k I'm unsure what to do. It sounds fine to me in this modified 511b but I have nothing to compare it to and before I start looking for a second one, I'd appreciate any input on whether this makes any sense at all, since the sound still has to travel through the 1" horn even though it's been widened to 1.4" at the entry. And does a 288-8k driver have any sonic advantage over a 808-8b with alum phram from say 700Hz up? (I don't like to cross too close to a horn's cutoff frequency)

I'm sure there will be many more questions in the future, but for now any help just to get fraltecstein to sing its first notes would be greatly appreciated.

Thanks, David

The modified 511b's are useless now. This might have been an attempt to make a 511E.

The 808-8B's should have the tangerine phase plugs. For high frequency extension use aluminum diaphragms in these. You would need two good 511b's, not expensive or hard to find.

Better yet, match the 288 and find horns for them They will sound better than the smaller format. The 288-k comes up on ebay and sells at reasonable prices, but horns for them are not quite as common. The mantra ray horns often sell for reasonable prices. The 291 (phenolic?) should fetch you some money.

David

**Old Guy** · December 28th, 2007, 05:25 PM

It may be possible to butcher the 511's, what Altec did was cut them off at the right point. You'd have to make a new mounting flange. other than that, they are useless.

An issue- the 421 is rear vented. If a front vent cap is installed you now have a front to rear air leak. Not good. Makes me wonder about the competency of the reconer.

As stated, replacement horns aren't hard to get.

Large format Altec horns bring a premium, except for Manta Rays. Lots of decent after market horns work fine with Altecs.

The 292 is phenolic, essentially an 8 ohm 290 without the transformer can.

With some careful changes, you should be able to wind up with a decent set of speakers.

**bowtie427ss** · December 28th, 2007, 06:26 PM

I'm dealing with a nasty cold and am thoroughly medicated, BUT, if i'm reading the OP correctly, he has 5(five) 511 horns of which only two have been molested meaning he's just two GPA phragms away from 802G's(808-8B's with alumaphrams) on 511b. Which while they're not of the ilk of the large format stuff, they're no slouches either. forums

I'd be tempted to silicone a couple aluminum can bottoms over the 421 vents and give them a listen as well as verify any cone numbers stamped on the back.

My WAG is that somebody just replaced the ugly creased and dented aluminum ones with vented caps.

[ December 28, 2007 02:28 PM: Message edited by: bowtie427ss ]

**Vathek** · December 30th, 2007, 03:37 PM

Sorry, I guess I wasn't very clear. I do indeed have five horns out of which only two are 'butchered'. So what I'm definitely going to do (as bowtie also suggested) is to get new diaphrams for the 808's. So I'll have two 802-8G's on 511b's. The only question here would be aluminum or pascalite.

Regarding the 421's, I've found several views on the internet, where people thought reconing 421's with other altec cones a very good thing to do. But the double-vent thing might be a problem and of course only the dust-cap won't do. On the cone the stamp says: 1803035430-01. Can anyone identify this?

Regarding the 'butchered' horns. The modifications basically do the same thing as a reversed 1" to 1.4" adapter would do. Now I'm sure this is not the best solution at all, but does that really make them useless as you all seem to agree?

But apart from that, are there any sonic advantages of the larger drivers except for the ability to play lower? 802-8G vs. 288-8K, better midrange? Is the topend just as extended? How would you characterize the differences?
Large format altec horns in europe are quite hard to find, but as you said there are many other horns to choose from.

I guess I'll sell the 292 and try to find a second 288, then I can answer all my questions by listening forums

Any insight on the 421 cone would be great.

**Old Guy** · December 30th, 2007, 03:49 PM

That sounds like an aftermarket number rather than an Altec number to me.

It's easy enoung for a reconer to replace the vented domes.

No those mods to the horns aren't the same.

What I was trying to say is they could be cut off at the right point to be 1.4" then new mounting flanges made.

Yes aluminum frams will essentially make a nice pair of drivers. i'd do that first.

The 808 has a loading cap over the fram-it should go. This means shorter mounting screws. The back cover then needs to be lined with felt- if you do a search it's been discussed her before. I mention this because if screw availability is an issue where you are, you may want to get a set when you order the frams.
Just doing those, some bracing, and the dust caps gets you close. Then some xovers.

Keep us posted!

**bfish** · December 30th, 2007, 10:30 PM

Originally posted by Old Guy:
That sounds like an aftermarket number rather than an Altec number to me...

That's the same part # format on Altec cones from the EV days. I presume Hawley or whoever actually made them assigned the part numbers to the customers spec, i.e. if EV was buying, they got EV numbers.

Somewhere here I've got an '80s EV list, but haven't seen it in a LONG time...too bad Telex pulled the plug on their FTP archives...

Added;
Haven't yet found the cone number in question, but it's not the EV designation for their 416 or 515 cones, so maybe it's the correct 421 kit from that era that somebody switched domes on??

[ December 30, 2007 11:02 PM: Message edited by: bfish ]

**bfish** · December 30th, 2007, 10:54 PM

Originally posted by Vathek:
...Regarding the 421's, I've found several views on the internet, where people thought reconing 421's with other altec cones a very good thing to do...

For what? Midbass horns? BR cabs? Certainly not the intended application.

Maybe they'd be "better" for a different application, maybe not. Point is, you don't know, and obviously whoever did it didn't care, or they'd have removed all traces of 421 ID, and relabled the unit with what(thehellever) it is now, and included a spec sheet detailing its' measured performance so the new owner might have a clue where to start.

[ December 30, 2007 10:56 PM: Message edited by: bfish ]

**bfish** · December 30th, 2007, 11:17 PM

Just for clarity, it's not your fault David. You're just the poor sucker that ended up with somebody's Fraltecstein.

[ December 30, 2007 10:53 PM: Message edited by: bfish ]

**Vathek** · March 21st, 2008, 08:39 PM

Guys, thanks for your advice! It's been a while, but I have had those not-so-fraltecsteins-anymore running for some time now. I put new Alu-phragms from GPA into those 808's, removed the loading caps and added some felt to the back. Fantastic!

The 421-xx are working fine, but it's hard for me to judge their performance without any comparison or lots of experience (of which I don't have neither). I'll probably replace them sometime anyway, but at the moment I first want to improve those 828 cabinets.

The cabinets are unbraced and the entire back is removable. The port-area at the bottom is of the horizontal-port-type that would let you mount the 511 inside of the cabinet. Now my idea was to change that to the two-vertical-ports-type. That makes it much easier to cross-brace the bottom half of the cabinet when I also make the bottom half of the back plate non-removable. That should improve the rigidity of those big boxes considerably.

What do you guys think of that? Is there something like 'standard improvements' for those cabinets?

David

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