Greetings:
This all sounds strangely familiar to an old Deadhead. Check out these two web pages on the Dead's former Wall of Sound, especially the design objectives:
http://www.dead.net/cavenweb/deadfile/newsletter19soundrap.html
and
http://www.dead.net/dicks_picks/4044/index_s.html (the second half of the page, where Bear himself evaluates the Wall in hindsight).

My question to Bose engineers is: how have you tackled the problems the Dead encountered, and was their Wall of Sound (or at least their objectives) any inspiration to you?

Thanks (and looking forward to a demo run of four PAS later this month)
Randy

Randy,

This approach is similar to the "wall of sound" idea but a bit more practical. Not being one of the original inventors, I'm not sure if this had any influence on the project as it was developing. Hopefully Cliff-at-Bose, the inventor, will post his thoughts.

It is vacation time right now and a lot of folks are out so it may not come for a week or two.

Hi Randy,

Another non-product-engineer chiming in here...

I'm another old Deadhead and had the same question when I first heard the Personalized Amplification System™. Though I never experienced the Wall of Sound (I was only 14 in '74), I've done some digging and found both differences and similarities.

Biggest difference - The Wall used conventional speaker enclosures - TONS of them! Though front-loaded (as opposed to the horns normally used in large venue, long-throw applications), they radiate sound 3-dimensionally (spherically) and must therefore have been louder at the stage than they were further back in the venue(1/r^2).

Biggest similarity - The Wall allowed the band members to mix themselves. What they heard was what the audience heard (except for perhaps lower volume further back).

Lots of other subtle differences and similarities, but I must get back to my real job! I'll look forward to hearing from the product engineers on this and will definitely be back to this thread when I'm off the clock...

quote:

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They're a band beyond description...

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Randy (and all the ships at sea)

The Dead were the first "big" band to try the monster PA behind the band, aimed at the audience. It wasn't really a "wall of sound" but a first attempt at an individual system for individual instruments. I'm told the system (shown in "dicks picks") sounded really beautiful in concert and not too loud, in fact very pleasant. Visually, the Cathedral-like system was simply stunning (see photo). This system had two big electroacoustical problems:

1. They had a central vocal system which used a very large array of mid devices and another of small HF devices shooting over the band. My guess is that they crossed from one to the other in the upper midrange. This gave 1/r2 performance (loud in front, soft in the back), as compared to the large line arrays they used (much less difference in levels front/back).

2. The line arrays used 12" and 15" speakers. They were very tall and so the 1/r performance reached into the bass region. But the horizontal width of these sources made them start to narrow horizontally, in the region of 1000 and 800 Hz respectively. An octave above this they would produce a 45 degree horizontal pattern and the "horizontal beaming" got progressively worse from there, making them unsuitable for full range use, even for bass guitar (whose spectrum extends all the way up). There was an attempt to aim some of these and also some use of HF devices in a colinear line configuration. Problems everywhere.

From an inventor's and artist's perspective, it was a glorious, brave and pure expression of amplified music, as an instrument to be played by a band. From an engineering perspective (hindsight, of course) it was a hornet's nest of electroacoustic (and other problems. I think the article points out that the system's usage on the road was short-lived, as it was prohibitively expensive and time-consuming to set up, this being a third problem for this large system.

Of course this was an inspiration to us, which we have duly noted (Ken's article online, for instance). We are all indebted to their courage in trying this. Unless you've been here (trying something unknown for the first time, in public), you can't really appreciate how difficult, terrifying and courageous an act like this really is. No parachute here. Everyone wants you to fail (no one wants their world rocked, like if you succeed) and will even try to get in your way. My guess is that there were legions of "self-appointed acoustical experts" standing around telling them what idiots they were. As they say "first Christian gets the hungriest lion". Same thing here. But, God-luv-m, they just went ahead and did it anyway, sort of like Carroll Shelby putting a 750hp NASCAR big-block engine into a little aluminium English sports car. The result (like the Cobra 427) is legend. So, hats off, as always, to the brave soldiers who came before us and paved the way.

I think our Personalized Amplification System (TM) has at least solved these three fundamental problems and musicians today are enjoying the benefits of an affordable, true wideband-1/r, compact and portable sound system concept that is helping them play more and better. And, lest we forget, more better.

This message has been edited. Last edited by: Col. Cliff-at-Bose,

Randy, this was a great post. very interesting. I had heard about the Greatful Dead's "WALL OF SOUND" but had never known what it technically was. Besides the vocal line-arrays, I was also amazed by their work with the differential microphones. This is the concept used by Crown's CM310 and311 mics which I have mentioned numerous times on this forum.
The idea of line array's using very small drivers is not new either. The French company Duran has been marketing this type of speaker system since the early 1990's. Here is a link with a photo of their "Intellivox" speaker. Very similar to the Bose MA12 ans L1 portion of the PAS.
Duran Intellivox
Steve gives Cliff at Bose credit as being the inventor of the PAS. I don't believe Cliff actually developed the technologies that when put together make up the PAS, but rather he had the brilliant idea to combine them into an all-in-one, integrated and portable product.
Robert L

Robert L,

I hear ya, but in my opinion, the challenge wasn't could this be done in theory, but how do you make it practical so that it can be done in practice. I've got a great idea for a perpetual motion machine ... but making it real, that's where I'm having running into challenges (like friction).

I also know that looking at other people's inventions sometimes I think "duh, I should have thought of that" but I still think of that as invention.

For example, the telephone was just a cool combination of known ideas right? Electricity over a wire, been done; microphone, done; speaker, all over it. But put it all togther and find a clever way to network them (a switch board operator) and now you've invented something.

That's my perspective and I still say Cliff (and Ken) invented something cool IMHO.

Now I need to learn more about those Crown mics, I've never checked into them; thanks for the reminder.