Need help - Altec 418B

[albertli]

Hi Guys,

I originally want to buy a pair of woofer, but bought a pair of 418B without checking the specification of the speakers.
I still wish to make use of them, if possible as a woofer, if not please advise what configuration will be best for this speakers.
Thanks in advance

Albert

[GM]

Greets!

It's a musical instrument driver best suited for a lead guitar amp or similar, so has a ~45 Hz Fs, ~0.3 Qts, high Vas (~250 L?) and very small Xmax (1.3 mm) IIRC: http://www.lansingheritage.org/image...-mi/page04.jpg

It has high efficiency, so if you drive it with a high output impedance amp it should play down into the 30s at modest SPL if the box is big enough and tuned low enough. Coupled to an Altec 811 horn and 1200-1500 Hz XO it will make a nice mini-M19: http://www.lansingheritage.org/html/...s/model-19.htm

GM

[albertli]

GM,

Thanks a bunch and nice to have you along.
According to the catalog, it seems to me the dimension including the 811 horn at the top. Would you be kind enough to show me the box dimension for the 418B as well since I'm a old newbie and a copy cat to be exact.

Albert

[bottom_feeder]

I use a pair of these in some monstrous Karlson enclosures . . . I only use them for the sub-120 hz material, as I have some DIY open baffle line arryas for the rest of the music spectrum.

they are SUPER efficient, and have some serious snap (and thump for that matter)

I don't like using them much higher than 150 - 200 Hz as I think they get kinda honky (they are MI speakers after all . . .)

I've never actually measured their frequency response in the Karlsons, but they seem to drop like a rock around their Fs . . .not a big deal for me really . . .

They like lotsa clean SS power, but I have used them with little tube amps too . . . best sound to date from them came from a BIG pro audio mixer putting out 400 watts RMS per channel . . . . ridiculous SPL levels . . . and great midbass snap in the Karlsons . . .

these Altec's really like to be spanked ! I ran the amp so it was just under the clipping threshold for about 5 hours at a DJ gig, and they could've played for DAYS at that level with no sweat.

good luck and have fun

[albertli]

Thanks so much for the suggestion, but I intent to run them with my 2A3 and or EL84pp

[Cal Weldon]

Moved to loudspeaker section.

[GM]

Originally posted by albertli
GM,

Would you be kind enough to show me the box dimension for the 418B........... I intent to run them with my 2A3 and or EL84pp

You're welcome!

OK, so you're saying you want to make a mini-M19 complete with 811 horn system or just a woofer cab or.......?

Regardless, I'll need your amp's output impedance (not their tap ratings) or at least their damping factors (DF) to ensure the cab is large enough to keep its bass line from sounding too 'warm'/'bloated'/'loose'. Otherwise, all I can do is assume a 'worst case' size tuned to Fs and you may have to reduce its internal size and re-tune the vent.

Also, any width/depth height preferences/limitations?

GM

[bottom_feeder]

Originally posted by albertli
Thanks so much for the suggestion, but I intent to run them with my 2A3 and or EL84pp

that should sound very nice . . . what are the output transformers on the two amps ?

[albertli]

GM, & bottom feeder.

The output transformer on my 2A3 are 2.5K double C core with 8R secondary and the EL84PP with a pair of Edcor 7.6K primary and 8R secondary.

GM, I personally love to make it a bass only speaker, so I could play around with different combination.

Albert

[albertli]

GM,

I thought I didn't answer your questions, but I don't know what are the damping factors of two of my amps. The EL84pp is ' The Bovois Vally' designed by Morgan Jones. A friend of mind gave me the schematic, but without any description.

Size of the box is not too critical.

Regards
Albert