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Altec Lansing Voice of the Theater Article

mmi

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Yeah, they certainly put a 15" to shame, but they are very uncommon in the wild. I've never run across a 30" woofer beyond the ones they used at the "Indiana Jones" ride at Disneyland.
Speaking of see the second most recent post on the Instagram linked in my comment above
 
OP
MakeMineVinyl

MakeMineVinyl

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I just carried out a series of measurements on my Altec Lansing A7-500 mains (left channel only). I did individual measurements with the microphone (Bruel & Kjaer type 2619 preamp head with 1/2" capsule) at the mouths of both the LF and HF horns, the port, and at the main listening position 11 feet away. I turned the subwoofers off for these measurements.

Kind of interesting is the very low distortion of the individual drivers, especially the HF horn which hovers between 0.1% and 0.2% through the mid-range - and this is at around 95dB SPL.

The crossover point between LF and HF horns is 500Hz, 2nd order LR.

For those who want to pick apart the .mdat REW file, it can be downloaded from here.
 
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fpitas

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Lovely...

Would dearly love to hear some of these famous big American horn loaded pro-audio speakers from yesteryear, but being uk based it seems unlikely unfortunately.

I'm a big fan of high sensitivity drivers and reckon the Altecs would be one of the few usage scenarios I can envision for the wee desktop amps like the Topping PA5, so popular with some folks here on ASR.


(Would look cool too...the amp/speaker size contrast!)
Vitavox was no slouch. You should be able to find those over there. Like any vintage speaker though, they may need restoration.
 

fpitas

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The 288 driver still appears on "best drivers of all time" lists to this day. I've heard my share, and understand that completely.
 

Jim Shaw

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It is good to keep in mind that VOTT speakers were originally designed for theaters. The last installation I personally heard had two VOTTs in a theatre seating max 700. They were loafing with 35-watt tube amps each. They were on dollies behind a flyable sound screen -- the theater was multi-use, with movies and live performances. They were only used for movies and were coupled directly to a pair of pro projectors. Other stuff did sound reinforcement.

Repurposing them for a much smaller room might be like trying to get more comfort by replacing a Bentley with a Greyhound bus. You can readily get them to play not-so-loud, but they are still floor space hogs. And while they sound good played softly, they were definitely designed to loaf along at very high SPLs in huge spaces.
.....
I agree with those who raise the issue of compression in bookie-size speakers. In my experience, the small speakers typically have lots of compression. It really shows up in playing recordings of pianos, horns, crash cymbals, and tympani for example. The little speakers shave off the tops' of percussive peaks. Casual listeners may not notice or take issue with this, but like everything else that's wrong, once you hear it, you can't unhear the effects. VOTTs don't typically do this. This may be why we worship them.

Compression is why I generally insist on hearing an excellent concert piano recording (Elton John or Billy Joel notwithstanding) when auditioning a new speaker. (For piano, I tend to select modern recordings by DG; Jan Lisiecki, Jussen Brothers, Lang Lang, etc.)

Here are some typical numbers: A concert grand piano, heard at 1 meter, can provide SPLs from near ambient (~30 dBA) to instantaneous peaks of upwards of 115 dBA. Modern digital recording can capture that. Few speakers can reproduce that at near-concert levels. Most will start serious compression at ~100 dBA at 1 meter. So what's the effect you hear at 90 dB at 4 meters? Small speakers play the main body of piano tone but shave off the top peaks. To the untrained listener, it still sounds like a piano, but to the trained listener, it sounds like the instantaneous peaks are missing. A dullness. Once you've heard it...
.....
I've had this discussion with technical listeners who are more serious about hearing tonality and timber. Often, they don't hear what classical piano-trained listeners find missing. They find my piano listening to be some sort of outlier fetish. But the same effects may apply to acoustic guitar. Xylophone. Steel drum. Celeste. Snare drum. Ad musicum...
 

mhardy6647

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The 288 driver still appears on "best drivers of all time" lists to this day. I've heard my share, and understand that completely.
+1, as they say.
The smoothness of a 288 is shocking, relative to so many other tweeters/treble drivers (particularly compression drivers).
 

fpitas

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+1, as they say.
The smoothness of a 288 is shocking, relative to so many other tweeters/treble drivers (particularly compression drivers).
I think that's part of the mystique about multicells. And they do sound good. Most used the 288.
 

fpitas

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[emphasis added]

yes. yes they do.
:)
511s can sound good, too. At least with a TAD TD-2002 driver. I've been told that putting a 288 on a 511 (the E suffix) makes them sound infinitely better.
 

beagleman

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This is a nice article about the legendary Altec Lansing Voice of the Theater A5 and A7 speakers.

I have owned an original pair of A7-500s since I bought them new in the late 1960s: I've reinforced the low frequency cabinet which was constructed of 5/8" plywood and applied massive damping material to the exterior of the 511 high frequency horns. Various active crossovers have been used, but I now use a 2 pole crossover at the original 500Hz; I like the quickness and projection of these lower frequencies from the HF horn. The LF is driven by either a MacIntosh MC240 or Dynaco MKIII and the HF is driven by a highly modified Cary single ended triode amp using 2A3 tubes. I use four 18" JBL subwoofers, each in an 8 cubic foot cabinet and operated in stereo to fill in the low frequencies below around 50Hz where the Altec cabinets start to roll off.

I have two pairs of original HF drivers, 802s with 34647 diaphragms and a franken-driver which is a 902 cast pot assembly with an 802 phase plug (the phase plug on these drivers was originally the plastic "Tangerine" type which I hated).

I eventually became an engineer at Altec Lansing when they were in Anaheim, CA. Needless to say, this was my hog-heaven job.

View attachment 202571
What room size do you have?
 

fordiebianco

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Fascinating discussion on fascinating speakers. But how do they measure (this is ASR..)?
 

Norway

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Here is my VOTT system. It’s app kg. 485 in total… it measures very flat from 100 up to 12 kHz.
 

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Paramedic

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Obviously I joined in here a little late but I just picked up a pair of Altec A5s. I already had 2 pairs of Altec 604s and could not resist the A5s which also came with a JBL sub woofer.
I saw how everybody was saying that they wanted to hear some Altec Voice of the Theater speakers and all I can think is that virtually every theater built between the 60's and the 90's had VOTT speakers in them so I am pretty sure most everybody has heard them.
20230514_204840.jpg
 

fpitas

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Fascinating discussion on fascinating speakers. But how do they measure (this is ASR..)?
Multicells with the 288 driver sound very natural, but have a very wavy directivity. That's inherent in the design, and was one of the reasons (besides cost) that Altec started down the radial horn path (which still have somewhat wavy directivity).

 
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