View Full Version : Altec Model Nine components

08-16-2003, 03:30 PM
Anybody know what these Altec consumer transducers are?

One's a 12-in, the other a "6-1/2 in frame" (clever size reference, eh?) mid-range. The only markings are "7 76".

I need part numbers and surround kits for each.

Help...? :yes:

Don McRitchie
08-16-2003, 06:07 PM
Part numbers are here:


08-16-2003, 10:29 PM
IIRC, the surround that fits a McIntosh ML2 12" woofer (the big-roll with flat internal lip) will fit fine on this Altec 12. It may require deleting the carboard gasket, but the increased roll size certainly won't hurt. If you want to retain the gasket, a standard 12" flat-internal-edge surround (make sure it's as SOFT and LIMBER as possible, to avoid making the bass boomy, which can happen with excessively stiff surrounds in these), should fit fine. BTW, I probably have both options in stock at work... if you want, you can get hold of us: www.audioatlanta.com

As for the midrange: believe it or not, I can concretely say, that the replacement surround for a Bose 901 driver (series 3 and up, ie, newer models) is an EXACT fit for the Altec mid. I've DONE two of these recently, with these exact surrounds, and it was a dead-on fit...

Be careful (heck, be paranoid) about NOT accidentally creasing or bending the cones on those mids. That crazy parabolic profile on that insanely thin paper stock, is REALLY easy to damage. If you somehow do manage to crease one of them, take some white glue, thin it with a little water, and soak that into the crease... this will generally reinforce the driver cone well enough that it will sound fine again...

Interesting how your model 9s have stamped-frame woofers... all the other ones I've seen, have had cast baskets. Must be a year model change somewhere... as the rest of the moving assembly (cone, etc) looks identical, otherwise...

Oh, BTW: this is one woofer, that I DEFINITELY recommend removing the dustcap and shimming the voice coil on, when you re-foam the driver. I've sucessfully done JBL LE10s, 127H's and such fine, without removing the caps... but the VC clearance on the last Altec Model 9 woofer I did, was SO tight, that there was virtually no way to get it straight enough to do full-travel without scraping, winging it by feel without removing the dustcaps. A bit of a pain, but if you're careful about peeling it off (score around it VERY LIGHTLY with an Exacto, and lift), you can most oftentimes just re-attach the same dustcap, right back in the original position, with white glue, good as new...


08-17-2003, 10:55 AM
Thanks, Don! ;) I had overlooked that reference sheet. Say, BTW, Page 3 is missing (there's two Page 2's). Just "fyi"...

Hey, GordonW...

this is one woofer, that I DEFINITELY recommend ... shimming the voice coil on ... the VC clearance on the last Altec Model 9 woofer I did, was SO tight, that there was virtually no way to get it straight So, what'd you use for a shim - or would you let me borrow yours...? ;)

Thanks for the help!

08-17-2003, 12:59 PM
...and do I really want to resurround it?

Anybody got T-S parameters for these (dreaded/orphaned) consumer components? GordonW?

The boys need a cabinet upgrade (and they're not yet ready for anything LARGE...), so I'm planning to refit the Model Nine cabinets with LE14A's, LE5-9's and either 2402's or 2405's, N65 network.

Oh - here's the dimensions:
- cabinet (exterior): 686 x 445 x 308 mm
- port (interior): 146 mm length x 75 mm diam.

Opinions? Worth the baffle work?

Here's the LE14A in the Model Nine cabinet - I've not yet modelled the N65...

08-17-2003, 09:31 PM
Actually, that Altec woofer isn't bad at all. It'll probably move more air in the bottom end (as well as go lower) than the LE14, most likely. While it's probably not as "fast" as the LE14, it's overall, a well-behaved woofer.

As for shims- I've used photo film, transparency sheet plastic, anything hard plastic sheet, as shims. I tend to use a "continuous" shim, where I simply fit a roll of something all the way around the gap. Best way to avoid warping a VC...

If you need to fit a size, taking something like the plastic film that some of the school report covers is made of, and rolling it up with a couple layers or so, should allow you to "sneak up" on the right thickness. Worked well for me before.

As for the mids- can't really make that decision for you. IME, they're not bad sounding, but something like an LE5 is better built, from a cone integrity standpoint, and should give less distortion.

As for tweeters: there's no question, the 2405 will KILL the Altec cone tweeter. Heck, an LE25 would probably be a slight improvement. Definitely the weak link of the system, IMHO...


Alex Lancaster
08-18-2003, 02:35 AM
I have used, exposed and developed old x-ray film, shimming all around; One plate will give You a lot of shims.

08-18-2003, 03:31 PM
Hey, GordonW...

...that Altec woofer isn't bad at all. It'll probably move more air in the bottom end (as well as go lower) than the LE14, most likely. Any chance you've got T-S param's on that Altec woofer? No one here has challenged your assertion :eek: , and it's got my attention, at least because the LE14A's I was planning to use would likely move easier on eBay. :D

08-19-2003, 06:39 PM
I haven't had one of the stamped-basket versions in hand, so take my comments with the requisite grain of salt, as compared to the cast version I've worked with.

That being said, the cast-basket woofers, have had a theoretical X-max (excursion capacity) of about 7mm each way. The voice coil is between 1/4" and 5/16" longer than the top plate, in each direction, when the VC is at rest position. AFAIK, that's significantly higher than the LE14, which IIRC, has an Xmax of about 4 mm or so.

Otherwise, sorry, I've never measured them for T/S parameters. I would make the assumption, though, that the Altec box should be pretty close (they usually are), with the only mods I might do, being possibly adding a bit more fiberglass stuffing/wall lining material, and possibly adjusting the port (I might try a bit longer, for a lower tuning frequency, to "smooth out" the bass, but that's just my taste, primarily)...


08-19-2003, 07:08 PM
Hey, GordonW...

So, I'm guessing you're in-the-market for some LE14A's eh...? ;)

Only kidding...

These Altec LF's "look" like their cheapest manufacturing, so I held little/no expectations for their competitiveness. I remember - back in the day - when I bought these Model Nine's new, I was most pleased and always of "crowded house". But, that was oh- so-long ago. At least two wives, four bands and equal number of fine dogs ago...

Interesting comment on the port - the few runs I've done suggest it is, in-fact, a bit short, for most possible LF injections. Odd.

With your experience on this vintage Altec consumer LF's, is it likely these are lesser than the cast frame version you've worked on? If not, I may forgo the planned LE14A infusion...

Thanks, for the input!

08-19-2003, 07:16 PM
Hey Bo

For what its worth give the Le-14A's a try. Obviously they can't come close to the 2245's in your 4345's or 2235's but they will surprise you. MDF is cheap drop them in 4cu.Ft and give them a listen as subs. Don't know how big your room is size wise or the intended application but I have yet to find something a pair of them can't keep up with. Beat the living daylights out of my 12" AR sub. Not that that the 12 is anything great mind you. I have a 3rd I will eventually use to replace the 12' LFE Sub. I have used them under 100dB 4655's and am using them under E145's now. Not bad at all just try one before you E-Bay them. You might like them.


08-19-2003, 08:20 PM
Hey, Rob...

Thanks! ;) I'm inclined that way too, not in any small way due to the lauds the LE14A transducer has received from an erudite protagonist here who's preferences I greatly respect. Plus, I'd like to work the baffle anew - you know, get the router real involved. If nothing else, it will be unique, and me and the boys will have built it. But, we'll see about that...

I am surprised the Altec LF would even compete! GordonW's experience has been real helpful. But, without T-S params, I may just have to wing it!


I will not use the LE14A's anywhere near the 4345's - that'd be silly, and a waste of the LE14A's. The 2245H's simply got it covered. Whoa...

08-20-2003, 06:50 PM
Hey, Gordon W...

I was re-reading your generous replies (thanks :D ), and wondered if you've run across this:

The mids have a hole through the pole piece, which (naturally...) connects through to the back of the dome. Maybe some early attempt at cooling venting - Ha!), but Altec covered this dang hole with a crummy little plastic disc glued to the back of the motor. Well, years ago, that glue dried out and the disk fell off, and rattled around in the cabinet. The mid is not in a acoustic isolation chamber, so that hole would allow cabinet pressure to react with the MF dome/cone. Dumber than dumb, cheaper than cheap.

Seen this?

08-21-2003, 11:07 AM
That little disk, is just to seal up the back chamber through the magnet, which is there to relieve the spring force behind the dustcap. Note that the dustcap is VERY thin on these- without the back chamber in the pole piece, you'd probably see dustcap cave-in on large transients.

I'd just glue the plastic disk back on; if you lost it, just glue the lid from a small pill bottle over the hole (anything approximately the same internal air volume inside. Just make sure that it's sealed... I've actually glued small plastic rigid dustcaps over the hole, and it worked fine, on a pair I had here to rebuild...

Oh, BTW: Bo, I'm checking on the 901 surround for you...