Altec 415 biflex drivers - what to do with them?

[nickbatz]

I have a pair of these drivers, which are about the same age I am (57)! After having them in my garage for ten years, it's time to do something with them or put them on ebay.

The driver has a concentric surround about halfway toward the middle. The idea is for one driver to cover bass and mid-high freqs. Please do a search for a picture if this doesn't make sense.

Obviously an active crossover is a better idea, and Altec sold horns separately for freqs >14K.

But is there anything to this concept?

My thought was to figure out the volume of the home plate-shaped box they specify for these drivers, and use cardboard concrete molds the right size.

Thoughts? Is it worth the effort - especially considering that I already have a pair of UREI 809As (which I really like)?

TIA

[Peter Larsen[_3_]]

nickbatz wrote:

> I have a pair of these drivers, which are about the same age I am
> (57)! After having them in my garage for ten years, it's time to do
> something with them or put them on ebay.

> The driver has a concentric surround about halfway toward the middle.
> The idea is for one driver to cover bass and mid-high freqs. Please
> do a search for a picture if this doesn't make sense.

I have seen a picture of them, I think. Possibly in a book, not in a
brochure.

> Obviously an active crossover is a better idea, and Altec sold horns
> separately for freqs >14K.

Above 14 kHz, nah - above 5 or 7 more likely - otoh, 8'tish Ohms and 2
microfarad lands around a corner at 10 kHz +/- the deviations caused by
driver impedance irregularity.

> But is there anything to this concept?

Do they have a voice coil for each part of the membrane or only one for
both?

> My thought was to figure out the volume of the home plate-shaped box
> they specify for these drivers, and use cardboard concrete molds the
> right size.

You would have to measure Linkwitz-Riley parameters then. But perhaps an
partial open back box is more "like it", kinda like a guitar amp. Wavy
quarter inch thick felt stapled to the sides and perhaps also to the rear
side of the front panel for "hi-fi".

> Thoughts? Is it worth the effort - especially considering that I
> already have a pair of UREI 809As (which I really like)?

Well, you need a 2 X 5 to 2 X 7 watt valve amp I reckon, but a sanely used
solid state amp may also be OK, highpass at 100 Hz first - or second -
order. Period audio can be great fun and sound surprisingly well using a
quality signal source. Even 78's played on a german HMV travel grammophone
have their charm. it ought to be fun enough to be worthwhile doing.

If dual voice coil - ie. real twoway and not just mechanically decoupled -
and IF you build a valve amp, then it begins to get interesting to build two
and try using a digital cross-over, perhaps a Behringer, you should be able
to find a second hand at a very reasonable price.

All advice based on an unskilled estimates, vague memories and partial
understanding, no guarantee of usefulness, deploy on own risk.

> TIA

Kind regards

Peter Larsen

[Peter Larsen[_3_]]

nickbatz wrote:

> I have a pair of these drivers, which are about the same age I am
> (57)! After having them in my garage for ten years, it's time to do
> something with them or put them on ebay.

15 Inch? - and yes, see

http://www.worthpoint.com/worthopedia/altec-lansing-415-biflex-speakers-imp-219731276

looks like separate high range voicecoil.

Looks seriously funny, git going! - open back box just needs to be a wee bit
bigger and you may perhaps put a 1 in front of the suggested amplifier size
to make it 15 watts valve "system power" used wisely, 15 and 5 for twoway
amplification, high pass perhaps lowered to 60 Hz.

Kind regards

Peter Larsen

[Scott Dorsey]

nickbatz > wrote:
>I have a pair of these drivers, which are about the same age I am (57)! After having them in my garage for ten years, it's time to do something with them or put them on ebay.
>
>The driver has a concentric surround about halfway toward the middle. The idea is for one driver to cover bass and mid-high freqs. Please do a search for a picture if this doesn't make sense.

A picture isn't going to help it make sense. The whole idea of sticking
two voice coils onto a single flexing cone assembly is one that does not
make sense.

It seemed like a good idea at the time, but really it wasn't. Put them on
Ebay Japan with a good description and photos. They will sell for good money
in Japan.

>My thought was to figure out the volume of the home plate-shaped box they specify for these drivers, and use cardboard concrete molds the right size.
>
>Thoughts? Is it worth the effort - especially considering that I already have a pair of UREI 809As (which I really like)?

It is not worth the effort, it was generally not a good design although
at the time when the alternatives were expensive coaxials and cheap whizzer
cone drivers, it seemed to fill a good center spot in Altec's line.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[nickbatz]

Thanks for the replies.

As far as I know there's just one voice coil.

http://www.voiceofthetheatre.com/images/412C.415C.1.jpg

But ebay Japan looks like the best idea.

[nickbatz]

By the way, the drivers come with specs for the speaker cabinet - one of which my dad built back in the day. He did a beautiful job, and it's been turned into a really nice-looking walnut corner book cabinet (again, the design is home plate-shaped).

I bought a second one on ebay about 13 years ago, thinking I'd make a stereo pair. But after 13 years...it's time to admit that I'm not in a hurry. :)