Altec 291a/329a/414 & Jbl 2405??

[timmytimtams]

Greetings to all forum members.

Just recently acquired an Altec speaker system. running 291A in a wooden 329a clone horn, 414 bass & JBL 2045 tweeter in a petite onken enclosure, crossed over with solen parts. i drove the system with a nice 8 watted 300b SET. to my ear it made lovely music, especially the beautifully etched mids, sweet highs, but somewhat lacking in the bottom oomphs.
Im a novice with all this vintage altec/JBL stuff.

i have a few knowledgeable friends who commented on how odd the combination was. greatly appreciated if any forum members could give their views on the setup. Very much would like to be educated. Thankyou in advance

[jandregg]

Nice looking horn. How do you like it?

John

[Tom Brennan]

The 414 is highly valued for it's gorgeous reproduction of mid and upper bass and midrange but isn't really noted for low bass capabilites. If you feel the need for more oomph on the bottom you may need a sub. More oomph in general can come from using double 414s per side as in the Heath AS-21.

Your combination may seem odd to some but it's sensible and I've no doubt it's capable of very fine sound.

[timmytimtams]

Hello John & Tom. Seasons greetings to you both. John, the altec sounded just wonderful especially with small ensemble vocal jazz, it threw out a vast soundstage, vocals are rendered beautifully. i guess one way to discribe it, is very analogue & coloured (nice) sounding.

Tom, thankyou for your kind advices. if time & funds permits i must look into getting a sub or extra 414s for each bin as you have suggested. One thing i would like to ask you is the demagnitising of the 291-16a compressor drivers. what does that actually achieves & is it worth while for me to getting it done? i heard the demagnitization of drivers bring it back to is original sounding best.

timmy

[speakerdave]

Alnico's are sometimes REmagnetized because they have become Demagnetized as the result of being overpowered with a high-current amplifier and sometimes the shock of being dropped. Overpowering is not commonly understood to occur with compression drivers since the voice coils would probably give out before the magnets are affected. The same would probably be the case with your 414's. I wouldn't worry about it.

For goodness sakes, do those spikes need to be directly on that nice floor?

David

[thansaffel]

I'd love to see some more pics of that horn from all angles. I have a 311-90 and recently saw a wooden clone that looked very difficult to build. 311-90s are not that easy to find and, having only one, I fantasized about building 2 from wood until I scored another aluminum one recently (knock wood - it hasn't arrived yet). I would love to see a build diary of one of these big wooden sectoral horns. Than

[spkrman57]

I'd love to see some more pics of that horn from all angles. I have a 311-90 and recently saw a wooden clone that looked very difficult to build. 311-90s are not that easy to find and, having only one, I fantasized about building 2 from wood until I scored another aluminum one recently (knock wood - it hasn't arrived yet). I would love to see a build diary of one of these big wooden sectoral horns. Than

I had a pair of 311-60's some time ago, and have not seen too many 311-60's or 311-90's around.

A few on e-bay, but they cost big bucks!

Regards, Ron

[thansaffel]

I wonder what the difference is between the profiles of the 329 and the 311.

Ron/spkrman57: I don't know why the 311 series is so scarce but I amazingly got the one I DO have from a guy who posted "Altec Horn $50" in a want-advertiser type of publication here in Monongalia County, WV. Yes, fifty bucks including the 291-16A driver!

I drove 25 miles south from Morgantown to meet the seller in the parking lot of a McDonald's where he had it in the back of his minivan. I initially thought, "this thing is hot"--as in stolen-- and maybe it was, but my friend Chris pointed out that the guy didn't know me from Adam and I could have been casing his home for all he knew. Hence the parking lot meetup . . . A rationalization maybe, but I'll take it!

As I mentioned, The driver is a 291-16A. It is not as well-regarded as the 288 series,but it is still a very good midrange match for my 416A midbass drivers. I have them in an open-backed 612-sized cabinet. I experimented with the jelabs open baffle and that did sound good, but the whole thing was just too big. The Valencia-sized open back 612 has good bass extension, fewer boxy reflections than an actual bass reflex cab or the 816A clones I did have the 416A in, and is about the right size for the 311-90 to sit on top. imaging is not as spookily full, but bass is tighter. The 291/311 sounds very good, clean, clear, detailed but smooth, crossed over actively at 350Hz and powered by a Bottlehead Paramour 2A3 SET amp.

I bought a mate for it on eBay December 31st after a long negotiation with the seller, who had posted it on eBay several times and amazingly never got a nibble. Guess the combo is too rare! I paid $575 including shipping. I figured I would never find a mate again as easily and with my "resourcefulness" the pair cost $625. If the mate is as good as the one I have it will be a bargain.

Crossed over at 350Hz, it is a perfect match for the 3-watt/channel SET paramour, which excel in their ability to render guitar, piano,and voice. It also removes the midrange from the solid-state amp I have powering the 416s, which currently are paired with 806As and 511B/811B horns depending on mood and status of loans/auditioning swaps with my audio buddy Chris.

The 416, in my opinion, is a perfect match for SS amps when restricted in frequency range from about 70Hz to about 350Hz. Any farther into the vocal range powered by SS and things seem to get restricted and honky. hence my wish to switch the entire midrange into the larger-format Altec drivers/horns--the goal is to keep the region from 300Hz to about 3000Hz as pure and phase-coherent as possible.

The second 311-90 with 291-16A is scheduled to arrive Monday. I can't stop thinking about it. I have never wanted a weekend to pass by as quickly as I want this one to!

I'll post some pix of the evolution of this system if there's any interest. Also my apologies up front if I've unintentionally hijacked this thread. I am a longtime lurker but a posting noob.

Than

[spkrman57]

The 311-60 is 60 degree dispersion while the 311-90 is 90 degree dispersion.

My 311-60's looked like a 311-90 with one section removed.

Cast aluminum did not ring, aquaplas coated to boot.

A friend of mine is still running them with Great Plains 399 1.4" drivers and they sound great!

Looking forward to pics of the final system!

Regards, Ron