Altec 421 woofer

[Conelrad]

I have a homebrew roadshow music/PA system with 421's in 815 cabinets. I drive them pretty hard with souped-up bi-amped Hafler D-500's. They are definitely tougher than 515's, but can really handle the work. Never lost a voice coil, but I have shattered one cone. Maybe it failed from age/brittle. Has made good money for me for over 12 years now with very little maintenance.

The top end is MR64 horns and 291H drivers.

Comments run from 'turn it down!' (ignored), to 'That stuff sounds awesome'....

DG

ps...A tip: never point the bins at each other...one good thump from a kick drum and the opposite HF horn driver diaphragm will shatter...the horn works both ways (think funnel).

[bfish]

...A tip: never point the bins at each other...one good thump from a kick drum and the opposite HF horn driver diaphragm will shatter...the horn works both ways (think funnel).

Absolutely. You'll only do it once though.

:welcome:

[scott fitlin]

True but...there isn't a whole lot of difference between an LF and regular 421. I don't think 421 LF replacement parts are available. GPA may be able to make up something.

It's a bit better than a standard 421. but not as nice as a 416. More comparable sound wise to a 3156. The regular 421's were also used in MI A7's.

The 421, regular or LF sounds very good in a properly tuned box. But regardless, it won't reach as low as a 416B will. I've measured.

However, with the current trend of a sub below 100 or so, it becomes a moot point.

We used to add a larger paper dome over the 421's aluminum one. The net result is a slight drop in resonance and efficiency, and a slight gain in LF extension.
Also eliminates or at least reduce artifacts from the aluminum dome.


It becomes pretty close, so close I think a 421 LF just has a slightly heavier coil.

Is the gap in the 421 series the same as the 515 and 416 drivers? OR, the 421 being a producer of sound, does it have a chamfered gap?

[bfish]

Parallel gap.

[scott fitlin]

Parallel gap.

Thanks, and I'll add to the 421 discussion, I used the 421-8LF for years, they sounded great. They don't reach as low as a 416, but the midbass they make is so clear sounding, and others opt to paint the aluminum dustcaps, or change them to paper, I've always had good results using EQ with a bit of cut at the offending frequencies, and while maybe this MI woofer isn't exactly what we would call ACCURATE HI FI, I just loved my 421-8LF,s in ALTEC basshorns. With Crown DC-300A,s and a pair of White 4200A EQ,s, and ALTEC horns on top of the cabinets they made some of the MOST REAL SOUND playing pre-recorded music I have ever heard, in my life. I have used 515,s and 416,s in my system, they are all EXCELLENT, but I got a special place in my head for the 421,s!