Altec Lansing

[jeff mai]

Originally posted by panomaniac
OK, while we're on the subject of Altec 825 and 828 cabinets - what makes them sound so good?

I didn't think the small Altec cabs sounded that great when I tried them. This is possibly influenced by having a pair of these cabinets to compare:



BIB!

[Geoff H]

Zen Mod

"I have room for them........
I'll do you a favor ,but you pay the freights"

I hadn't considered adoption....
Just did. Nope.

Panomaniac.

"Turntable in another room? You're hard core, Geoff!"

I hinted at that in post 25. GM knows where I'm coming from - post 52.
Don't worry Michael, one day you might get some real speakers.
You read about people hearing the differences between CD players, etc. I could hear when the Thorens needed an oil change. Serious.

The Altec enclosures are what I refer to as real BR, as oposed to those hissing air pumps - ducts. The port is sized according to the piston diameter eg 80%, and the cabinet size adjusted to tune the assembly.

The flare in front of the driver is a horn. In the case of the A7, going down to about 150 Hz. That's the bit that makes Saxophones, lower male vocals, violas etc stand out in the crowd. They are in reality a 3 way system.

Jeff Mai. I think we have grasped the concept that big is better. Now take your horn to your room.

Do you have a front view?

[Pano]

Now, now Jeff (with a J),
Play nice! We can't all trot out or "Bigger is Better, yours is not Big enough." So let's not go there.

Honestly, I've heard the big Altecs, like the A4s and the JBL clones. They sound great, they sound big, and they fill a huge cinema. But I'll take the modified 828 cabs with the 1505 horns any day. Why?

More natural. More realistic. Tighter. At least in a normal size room. A lot of old sound guys I knew would laugh at me when I told them how much I liked those cabinets. But they never heard a really tight, strong version with the 1505 on top.

Construction of the Altec cabinets was not always of the highest quality. Redoubling the walls with extremely dense plywood transformed them. Internal bracing, felt damping and tar helped too. No box sound at all. None. The design is good, if it's well built. Of course the A4s would rule if built up to those standards too.

Geoff (with a G)

Yep, horn loading on the 15" driver. But why? It usually isn't the 150Hz and up region that needs help. So why horn load it? Doesn't that tilt the response up? Is that part of the sound signature? Or is there something else going on?

[Cameron Glendin]

The Voice of the Theatre Models were designed in the era of 2000 plus seat cinemas and 30 watt valve amps, the horn loading of the bass was for efficency and long throw. Also the horn loading would control directionallity minimising early reflections and therefore increase intelligability in those potential echo chambers called auditoriums.

Ps some think that the JBL's were better, I was impressed by the sound myself.

[Pano]

Which JBLs do you mean, Cameron?

[Geoff H]

panomaniac, I have a long established theory to your question, "but why" No physics to prove it however.

I believe for a speaker to reproduce a sound accurately, it must have some resemblance in size to the radiating surface of the instrument. If the effective surface area of the cone is smaller than the original radiating surface, it must travel futher to achieve a similar SPL.

If you take your average up market so called HiFi speaker with the classic 12" + 5" + 1" and crossovers at 500, + 5K, and ask yourself when any of those drivers, or combination, has resemblance to a musical instrument? You must have seen how far the skin on a bass drum travels. The above woofer has to travel twice that distance to achieve anything like the same sonic impact. Violin - off a 5" cone? And what does a 1" dome ressemble? A 15" diameter brass symbol, I don't think so, yet that is what we ask of it.

The horn enlarges the radiating surface, and also provides better impedance matching from the cone to the air. (That is physics)

Maybe others have a different take on it.

Geoff.

[fred76]

current repro 825 clones in Japan cost a mint (w/ WE field coil driver clones)

http://www.gip-laboratory.com/seihinn825system.html
WE587A tweeter clones optional

http://www.gip-laboratory.com/
the 'Interigence' part...

similar competitor for drivers: http://www.eltus.net/english/index-e.html

whoever snagged these very rare minty field coil driver/horn combo pair is lucky:
http://www.hifido.co.jp/cgi-bin/oldh...4-11-27&lang=e
http://www11.plala.or.jp/teikakakuco...nit/d51ex.html
http://www11.plala.or.jp/teikakakuco...nit/hc501.html

How do these latter Mantaray+bassbin types compare to the early models?
http://www16.plala.or.jp/footpointof...rn-System.html

[jeff mai]

Originally posted by panomaniac
Construction of the Altec cabinets was not always of the highest quality. Redoubling the walls with extremely dense plywood transformed them. Internal bracing, felt damping and tar helped too.

To be fair, I never tried to get the most out of the smaller Altec cabinets. I think part of the reason I preferred the bigger RCA cabs (identical to the above picture I posted) is they were much more heavily constructed.

For the amount of space any of these large cabinets used, I'd prefer a straight horn and a separate ported sub below 70 Hz. Those big RCA cabs sure were fun at the time!

[Cal Weldon]

Pano,

What? Are you saying that using nails for curved panels is not high quality?

[phn]

I hope I haven't missed any posts.

Altec A-4

Unfortunately, too big for my room.