ALS DEMO Bob Carver James Sauter Bob Farinelli Les Williams

http://www.audiokarma.org/forums/showthread.php?t=390387

thanks rabbit....

A reply from Bob on the Audiokarma thread discussion.
I will be posting there as well.

Bob Carver here.

I've been reading the commentary on my new speaker and find the interest very exciting. Some of the comments I will address now.

One: It can't be done

My answer: Of course it can. Not only that, but I am used to being accused of inventing things that can't be done, beginning with the Phase Linear 700 watt amplifier of long ago, all the way to my current high-pressure subwoofer. So I'm used to that.

Two: The ribbon looks like it's from Parts Express

Of course it is. I designed that ribbon over thirteen years ago for a loudspeaker I ended up developing and calling the Sunfire Cinema Ribbon. The ribbon was built in China by Hi-Vi for Homni, my Chinese supplier for drivers at the time. Shortly thereafter I sold the design to Hi-Vi as part of a joint cooperation agreement for manufacturing tooling, and subsequently it was delivered into the public domain by my intent. Hi-Vi, under the joint cooperation agreement, markets it worldwide and now sells it to Parts Express. Again, it was originally designed for my Cinema Ribbon and is still used in Cinema Ribbons today. It is truly an amazing ribbon, if I do say so myself.

Three: 121dB SPL

121dB SPL is an enormous sound pressure level but the numbers that teach us how it does that are comprised of simple arithmetic. I begin: A pair of the small woofers as utilized in the tried-and-true Cinema Ribbons produce a loudspeaker that has a sensitivity of 89dB SPL. The Cinema Ribbon was designed to absorb all the power that my 200 watt per channel amplifier could deliver. At 80 Hz it's peak-to-peak excursion is 0.48". Now, my new Amazing Line Source speaker has 22 of these drivers per channel. Since each driver can take 100 watts (92 watts with crossover losses), how much can each Amazing Line Source speaker handle? Well, 92 x 22 is 2,024 watts.  At those power levels and at 80 Hz, those woofers are moving back and forth 0.48". Or, from another point of view, 80Hz/4 (20 Hz) allows equalization and yields flat response down to 20 Hz with a 450 watt per channel amplifier, assuming a room gain of 8dB at 20 Hz (Theoretically it's 3dB per boundary, and there are three boundaries in a room for each speaker).

Four: Low Frequency Response

A line source that goes from floor to ceiling is a weird, spooky, and interesting thing. Imagine that your floor and ceiling are mirrors, and the line source has 22 candles instead of woofers. If we look at it, we will see candles going up infinitely to the sky and down infinitely below. The amazing thing is that each reflection of each candle generates real light and so do the reflected sound sources of the line array. Spooky because it seems as if it's something for nothing, and it almost is!  The same holds true for the ribbons. Each ribbon, on speech and music, can easily absorb 200 watts rms and there are thirteen of them per channel. Finally, 200 watts x 13 = 2600 watts - a walk in the park for these ribbons!

Five: Sensitivity - 96dB

Each time the area or the displacement is doubled - all other things held constant - the sensitivity increases 6dB. Here is the arithmetic: One ribbon = 89dB. two ribbons = 95dB. Four ribbons = 101dB. Eight ribbons is 107dB, and 16 ribbons would be 113dB sensitivity IF the voltage across each were held constant. Since these ribbons are in a complex series/parallel configuration we must subtract 17dB because the voltage across each ribbon is substantially lower (approximately 20% of the original voltage) yielding 96dB SPL sensitivity. The precise calculation is as follows: There are thirteen ribbons, so 10 x log(13) is 11dB. 11 + 89 = 100dB, and the crossover throws away 4dB, for a net of 96dB sensitivity. That's the science.

Six: "Distortionless"

Strictly speaking, nothing is distortionless. However, in hi-fi, if the distortion is below our threshold of audibility we can color it gone. If it's gone we can't hear it and I consider it sufficiently distortionless to call it thus in my use of colloquial English.

Seven: "fast and loose with hyperbole"

I plead guilty for hyperbole, not guilty for fast and loose; my designs always deliver the performance and the numbers, for real, every time, as evidenced by independent reviewers over and over again through the years. Wait and see.

Thanks guys, your comments and passionate responses to this new loudspeaker have made me think.

Great comments, warmest and best,

Bob Carver

I'm quite interested to hear their responses on his response.

I need Gary to post it... Still waiting for my account to be activated over there

=D>

Everyone needs to read this! Don't take no shit Bob - Your the "of course it can MAN!"

I thought it was a good rebuttal. No anger, just the facts.

Awesome. Who needs a marketing machine when you have the man himself?

I thought it was a good rebuttal. No anger, just the facts.

Yes - the facts!
Yes - No anger
Yes - He found a way
Yes - Bob can do that
Yes - its proven
Yes - YES
The BobFather

James, I'm set to hit GO & post Bob's response; want me to send it?

Just looked myself over there na dth ethread is closed. Bob's comments are nowhere to be found.

James, I'm set to hit GO & post Bob's response; want me to send it?

Dad says yes, but make it a good title so it catches everyone's eye.

Posted: http://www.audiokarma.org/forums/showth ... ost4955981

Title: Bob Carver reply to questions/comments on his new Amazing Line Source speakers~

Posted: http://www.audiokarma.org/forums/showth ... ost4955981

Title: Bob Carver reply to questions/comments on his new Amazing Line Source speakers~

try this link.....

http://www.audiokarma.org/forums/showth ... p?t=391704

Some initial comments on Bob's response:

"Whatever you think of the product, the dude is no shrinking violet. "

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"Interesting info; thanks for posting it!

Quote: Floor to what height ceiling?
Quote: The speakers are 90 inches tall from what I have read.

With line arrays, as long as the speakers at the top and bottom ends are close enough to the ceiling and floor, the "coupling" effect will occur, just like mirrors, just as Bob Carver described. They need not go all the way; just sufficiently close. If those speakers are 90 inches tall, that's 7-1/2 feet, more than enough to couple effectively with a typical 8 or 9 foot ceiling. In the real world, coupling of speakers in line arrays doesn't meet the theoretical aims, because of factors like partial absorption by the ceiling and floor, the effects of air itself, etc... but it comes way close enough to sound pretty darned good!

...Interesting that those Parts Express ribbons are the same ones as in the Sunfire Cinemas... might be a bargain, at that!? "


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"I do appreciate these responses which are clearly heartfelt and articulate. It's nice for a guy of his undeniable stature in this game to even bother with responding to a bunch of unwashed critics like me. I will disclose/confess that I run hot and cold in response to Mr. Carver's exploits over the years - back to and including the 700(B).

I am reminded of the poor treatment that James Bongornio received from the rabble at fmtunerinfo.com (although Mr. Bongornio doesn't suffer fools too gracefully), so I do hope we don't get involved in a urinating contest with Mr. Carver.

That said, am I the only one who detects a bit of a philosophical disconnect between these two responses?

Originally Posted by TNRabbit View Post
Six: "Distortionless"

Strictly speaking, nothing is distortionless. However, in hi-fi, if the distortion is below our threshold of audibility we can color it gone. If it's gone we can't hear it and I consider it sufficiently distortionless to call it thus in my use of colloquial English.

Seven: "fast and loose with hyperbole"

I plead guilty for hyperbole, not guilty for fast and loose; my designs always deliver the performance and the numbers, for real, every time, as evidenced by independent reviewers over and over again through the years. Wait and see.

...

Great comments, warmest and best,

Bob Carver

If the numbers are indeed delivered, why no distortion numbers in this case? Col. Paul W. "no BS" Klipsch, for one, certainly had some strong opinions about the importance of low distortion (which, in Klipsch's analysis, is best achieved through low amounts of diaphragm excursion and letting horns do their work as acoustic transformers) in loudspeakers. My own approach to evaluation of loudspeakers - hobbyist that I am - is far more empirical ("suck it and see") than quantitative... but if one promises the numbers, one should feel duty bound to deliver the numbers.

Certainly fair enough to wait until a final configuration is established before publishing quantitative performance data on these loudspeakers.

BTW, I have no beef with the genesis of the tweeter. The little Peerless AlNiCo 2" cones (not to mention their KO10DT 1" silk domes) were cheap, but found employment in some fine and hardly inexpensive loudspeakers in their time."

More comments:

Very cool to see answers to the questions posted on the site, and as predicted.. Bob likes the attention

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It is interesting to hear that the ribbons were designed by Bob and are now distributed by PE. I have to chuckle after so many insisted they weren't. Now I really want to use/hear a pair!

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No such thing as bad publicity, as the old saw has it...

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(RE- distortion): Sophistry. No means no.

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Bob’s “hyperbole” always made me smile and provided a bit of light heartedness to a hobby that sometimes can become overbearingly serious.
In juxtaposition with that tongue and cheek humor he never failed to deliver in spades technically.

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From what I have seen, read and heard Bob Carver is too cool to let anyone else's words worry him.

I look forward to this becoming a commercial product.

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I like this Bob Carver guy, he's alright.

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Nice to hear from Bob, clearing up some of the confusion in the prior speaker thread.

For me, some of the impact was lost with the reply being pasted here instead of Bob logging in and posting it.

That's just my opinion.


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I like this Bob Carver, guy, too. He seems to not take himself too seriously. I just don't recall ever hearing one of his creations that I've liked. I'd like to hear these speakers, though. The world certainly isn't harmed by another pair of speakers made by some guy who just seems to like to play around with this stuff (and sell it with, well, hyperbole).

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Oh come on man, Mr Carver has taken the time to respond to unwarranted criticism, which I am sure is more then most designers would have done, and now you are going to fault him for not joining AK and posting it himself? Sorry but ,with all due respect, that is just plain ridiculous

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He is already a member here (as was pointed out in an earlier post to this thread).

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AK comments continued:

I thought it was real nice of him to take the time to write a candid response. How many other big-name designers can you name who have done that lately? He comes across as a regular guy who is willing to talk with regular people, who's not overly sensitive to criticism ("I made a thing, here's my thought process, hope you like it, if you don't, I'm not going to take it personally"). I wish more people were like that.

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Bob for president.

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Mr. Carver is a big boy and can speak for himself. That's the whole idea here and as was pointed out, Mr. Carver is a member here.

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If he posted here he would be drawn into a time consuming and useless debate.

The speakers will speak for themselves soon enough.

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