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[Lee Buckalew]

Ultimately, isn't the problem trying to achieve  reasonably flat phase and frequency response at every listener location in the hall or on the field? 

The question is how to do this, the problem(s) would be those things that stop us from doing this.  That is precisely why Cellular Drive development began. 
But that is not the question that was generally being asked, the question that was typically being asked by speaker builders was, "how do we achieve flat phase and frequency response from each driver, speaker enclosure, combination of speaker enclosures?"  Which is a great question where we have a single listener and/or in the case of a fully coherent multi-driver assembly, when we never need to use more than one assembly/cabinet to achieve the necessary coverage.

Taking into the equation the number of possible changes available to a system be it MLA, ANNYA, KV2, Danley, L'acoustics, Meyer, D&B, et al, there wouldn't be enough permutations to provide close to ideal.

But it is being done with Cellular Drive in the MLA form factor now through a combination of purpose designed, purpose built; drivers, speaker cabinets, measurement models, modeling software, etc.  It certainly does require many, many very intensive mathematical computations.  It took a military supercomputer to do the model development. 
It is a completely different approach that no one else has done because they have taken into account how the speaker elements and speakers actually behave in each possible combination and then used this to create accurate models.

Perhaps we need to start looking more at finding practical solutions?  It's well known that our hearing adapts, go to a concert with too much top end on the system and after about 10 mins it sounds about right.  Similarly, engineers tweaking eq only to find the eq is by-passed.  Perhaps more work in exploiting the weaknesses in our perception to gain where we are most sensitive?

Unfortunately we can not hear what has been cancelled.  We may be able to get accustomed to it (that's the way this room, band, concert, movie, sounds) but that does not mean that we do not want to translate an artistic vision, be it the music of a band or the soundtrack and dialogue of a movie, to the listener as accurately and with as high a resolution as is possible when given the opportunity.
Exploiting the weaknesses in our auditory perception is a job for sound designers of film, TV, and movies as they use psychoacoustic principles to trick us into believing we are hearing what we are not or we are not hearing what we are.  In most cases, with a few exceptions, the job of the sound system designer, system tech, mixing engineer is to accurately translate an input or group of inputs so that it can be heard as intended by an audience.

Lee

[Steve M Smith]

engineers tweaking eq only to find the eq is by-passed.

As if anyone would ever do that!!!


Steve.

[thirtha chengappa]

I really appreciate the tech talk that has taken place on this thread. Taking the liberty to deviate a bit, it would be relevant to pay attention to real world market, the quality of the audiences ears, and unfortunately, their eyes.

As far as the audiences ears go, we would not have this  if they had astute hearing that we members have on this forum -

http://forums.prosoundweb.com/index.php/topic,160129.0.html

And they, the audience eventually pay us, directly or indirectly.

The point is this, ...... everything comes down to price - Point source VS line array.

More importantly, it, unfortunately comes down to quantity. For the price of a KV2 VHD 2.0 or the VHD 5, the numbers that comes in comparison to a conventional "line array" manufactured by a "reputed" manufacturer would make it more attractive for the vendor, the event organizer, and the artiest to see, not to forget the audience. The proof of that, is that a particular well marketed brand's logo can virtually add +3 DB to the rig at play in the audience's perception.  Sad but true.

I have attended 3 palm show (India) line array demonstrations in the past 3 years. The "point source" KV2 VHD2 stood out in comparison to the other 12 odd line arrays out there, each of these 12 odd lines hangs with nothing less that 8 numbers, and in a 3 way format to boot.

The KV2 was way ahead in term of clarity and SPL. And yet, the only sales that made every year were made by the manufacturers of  "conventional" line array formats. To the best of my knowledge, there is only one VHD rig in India right now. Sad but true.

Is this the same problem in the rest of the world? As far as India goes, this seems to be the case. It's not that there is a lack of money. The sales personal at Harman India proudly told me that one Indian state capital alone has 12 Vertec 4889 rigs with 8 + modules per side minimum (matching number of subs). The same state capital has 5 VTX rigs with 10 per side minimum (matching number of subs).  India has 22 states. Harman is just another manufacturer in India. This, after we play close to 48 % in tax on the Invoice value.

Why is it, that the point source concept like the KV2, and not to forget Danley, not taken off In a big market like India? I Am baffled. Is it just the lack of marketing or the lack of understanding of a concept?

[Tom Danley]

I really appreciate the tech talk that has taken place on this thread. Taking the liberty to deviate a bit, it would be relevant to pay attention to real world market, the quality of the audiences ears, and unfortunately, their eyes.

As far as the audiences ears go, we would not have this  if they had astute hearing that we members have on this forum -

http://forums.prosoundweb.com/index.php/topic,160129.0.html

And they, the audience eventually pay us, directly or indirectly.

The point is this, ...... everything comes down to price - Point source VS line array.

More importantly, it, unfortunately comes down to quantity. For the price of a KV2 VHD 2.0 or the VHD 5, the numbers that comes in comparison to a conventional "line array" manufactured by a "reputed" manufacturer would make it more attractive for the vendor, the event organizer, and the artiest to see, not to forget the audience. The proof of that, is that a particular well marketed brand's logo can virtually add +3 DB to the rig at play in the audience's perception.  Sad but true.

I have attended 3 palm show (India) line array demonstrations in the past 3 years. The "point source" KV2 VHD2 stood out in comparison to the other 12 odd line arrays out there, each of these 12 odd lines hangs with nothing less that 8 numbers, and in a 3 way format to boot.

The KV2 was way ahead in term of clarity and SPL. And yet, the only sales that made every year were made by the manufacturers of  "conventional" line array formats. To the best of my knowledge, there is only one VHD rig in India right now. Sad but true.

Is this the same problem in the rest of the world? As far as India goes, this seems to be the case. It's not that there is a lack of money. The sales personal at Harman India proudly told me that one Indian state capital alone has 12 Vertec 4889 rigs with 8 + modules per side minimum (matching number of subs). The same state capital has 5 VTX rigs with 10 per side minimum (matching number of subs).  India has 22 states. Harman is just another manufacturer in India. This, after we play close to 48 % in tax on the Invoice value.

Why is it, that the point source concept like the KV2, and not to forget Danley, not taken off In a big market like India? I Am baffled. Is it just the lack of marketing or the lack of understanding of a concept?

Hi Thirtha
In any significant market sector be it from cars, to wood preservatives, to politics,  to food products, the largest, best selling and most well known brands are normally not the ones that deliver the biggest “bang for the buck” or best performance.   Like they say in marketing “a dollar spent promoting the image of science produces more sales than a dollar spent on science”

The top sales positions instead normally goes to the ones with the most marketing and promotional efforts.
     
Since  you mentioned us by name, I have not heard the KV2 products but they may be up against what we recognized to be a nearly unwinnable battle against the cumulative effect of so many companies marketing line arrays, in fact while a number of us are live sound folks, we elected not to even try to compete in the live sound area where the arrays are so dominant and the lore so deeply embedded.     

Instead we focused on large venues and stadiums where the owners aren’t happy with line arrays they have and don’t give a hoot about brand recognition or rider acceptance and with essentially no advertising, in the last 6 years, as a result of side by side demo’s like you speak of, have replaced those systems with ours in about half of the country’s 100,000+ seat stadiums so far with more on the way next season.   
So far as your country, I would guess the same things drive popularity in your sound market as they do here but like here, there are probably some who still seek the best results.  If i were KV2 in your country, i would try to reach them and do demos.
Best,
Tom Danley

[thirtha chengappa]

Hi Thirtha
Like they say in marketing “a dollar spent promoting the image of science produces more sales than a dollar spent on science”
The top sales positions instead normally goes to the ones with the most marketing and promotional efforts.

Hats off to you sir. You said it best. Why I took your name is that I inherently understand what you say and I take the liberty to quote you .....

" It is the technology which allows us to put multiple drivers of different bandwidths into a single horn, and make them behave as a single full range loudspeaker. "

I put you and KV2 on the same page because both are, .... to the best of my understanding, please correct me if I am wrong, trying to do the same thing on a very broad spectrum.

Having heard many a line array, especially the Chinese brands that do the most damage via selling substandard stuff for a cheap price, I can say that the technology that you propound makes sense on many levels.  I must admit that I have not heard any of your products, but would love to do so. It's very nice of you to take the time out to reply to my post. Thank you.

[Mike Hedden]

"An exact and unique solution does not exist since in general there are more equations than unknowns" - Dr. Evert Start

AFAIK Dr. Evert Start of Duran-Audio aka Axys in the Netherlands, now owned by Harman / JBL Pro, was the first to come up with a solution to this challenge.

Verzonden vanaf mijn iPad met Tapatalk

Why Dr. Start isn't a household name in the world of the dsp controlled arrays is beyond me. He developed these approaches many years before most of the products that are now considered "groundbreaking" were conceived.  Every steerable column product currently on the market was developed in reaction to Dr. Start's Intellivox products and his concert products, Axsys, were also years ahead of their time.  At the Syn Aud Con Loudspeaker workshop in Louisville Ky over a decade ago, Dr. Start did a thorough presentation as to how they measured their Axsys product and to date, I've never seen another line array technical presentation this detailed and revealing.  He also appeared to be to be a humble gentlemen.

Mike Hedden
Danley Sound Labs, Inc.

[Mark Wilkinson]

Thanks Tom, Thanks Lee,

Yes, miniDSP and rephase was the only way this poor boy could find, to jump into FIR world with enough taps to really experiment down low.

Tom, your reply and Lee's posts are opening my eyes to where I've been having difficulty with VHF, and understanding what MLA is doing. I don't want to mire this great thread with my specific VHF issue, but for me at least it turns into an example of how Cellar Drive differs from traditional tuning.

I've used rephase to flatten driver-by-driver magnitude and phase, and add linear-phase x-over filters, via miniDSP.
It's pretty easy to get individual driver traces that look good in smaart...(even on the subs when I can live with the processing time lol.) The HF and VHF come from a single BMS4594 coax....both traces show flat zero phase throughout their passbands and 48LR x-over regions around 6300hz.
So then, I'd put it all together, adjust levels, and set time offsets via the dsp in my power amps running at 48khz.
System trace looks great, except VHF inevitably slopes up or down about 60 degrees from about 14khz to 20khz, depending on one click of the smallest time offset I can make via the amp (0.02ms).  This was the genesis of my earlier doubt.

I've realized the fallacy of tuning to a single location, and have made a 3 mic rig on a boom for averaging measurements, and still get the same "can't phase flatten the final tail" phenom.
I'm thinking the interference issues you point me to may be...or I'm just still screwing something up

Truly would love to be able to try an active FIR setup on one of your boxes.  Given their extraordinary physical alignment, I have to believe it would be some of the easiest FIR work ever !!!

At any rate, I apologize if this has swerved excessively, and to return...

Lee, 

in a later post you say "the question that was typically being asked by speaker builders was, "how do we achieve flat phase and frequency response from each driver, speaker enclosure, combination of speaker enclosures?"  Which is a great question where we have a single listener and/or in the case of a fully coherent multi-driver assembly, when we never need to use more than one assembly/cabinet to achieve the necessary coverage."

Yes, this is exactly what I've been doing and have trying to apply that thinking to line arrays, ultimately believing it just boiled down to adjusting driver by driver....

Let's just say the Cellular Drive lights went on and I'm seeing the need for MLA's  immense computational power!!!!!

Thx guys, Mark

[Lee Buckalew]

Lee, 

in a later post you say "the question that was typically being asked by speaker builders was, "how do we achieve flat phase and frequency response from each driver, speaker enclosure, combination of speaker enclosures?"  Which is a great question where we have a single listener and/or in the case of a fully coherent multi-driver assembly, when we never need to use more than one assembly/cabinet to achieve the necessary coverage."

Yes, this is exactly what I've been doing and have trying to apply that thinking to line arrays, ultimately believing it just boiled down to adjusting driver by driver....

Let's just say the Cellular Drive lights went on and I'm seeing the need for MLA's  immense computational power!!!!!

Thx guys, Mark

Glad to help turn the lights on :-)

That's the frustrating part of frequently running into the uninformed opinion that MLA is "just using beam steering", or is "just a processed line array".  It is neither, Cellular Drive is a unique approach and is now a patented process.  It is not a form factor or a cabinet layout, it is a complete process that is different than anything that has been done before. 

That still does not make it the right choice for everything or a perfect solution by any means but it is a very powerful tool to understand and have in your toolbar.

Lee

[Tom Danley]

Thanks Tom, Thanks Lee,

Yes, miniDSP and rephase was the only way this poor boy could find, to jump into FIR world with enough taps to really experiment down low.

Tom, your reply and Lee's posts are opening my eyes to where I've been having difficulty with VHF, and understanding what MLA is doing. I don't want to mire this great thread with my specific VHF issue, but for me at least it turns into an example of how Cellar Drive differs from traditional tuning.

I've used rephase to flatten driver-by-driver magnitude and phase, and add linear-phase x-over filters, via miniDSP.
It's pretty easy to get individual driver traces that look good in smaart...(even on the subs when I can live with the processing time lol.) The HF and VHF come from a single BMS4594 coax....both traces show flat zero phase throughout their passbands and 48LR x-over regions around 6300hz.
So then, I'd put it all together, adjust levels, and set time offsets via the dsp in my power amps running at 48khz.
System trace looks great, except VHF inevitably slopes up or down about 60 degrees from about 14khz to 20khz, depending on one click of the smallest time offset I can make via the amp (0.02ms).  This was the genesis of my earlier doubt.

I've realized the fallacy of tuning to a single location, and have made a 3 mic rig on a boom for averaging measurements, and still get the same "can't phase flatten the final tail" phenom.
I'm thinking the interference issues you point me to may be...or I'm just still screwing something up

Hi Mark
Try getting it as close as possible first without DSP and on that driver if i recall the mid needs to be inverted relative to the hf section and for a 6300Hz L&R 4th order xover, try delaying the hf about .2 to .18 ms with the crossover as the two sources are not perfectly aligned in time at the origin.  Fiddle with the frequency and delay a tiny bit to get as close to " one source" as you can, then apply the dsp as a final correction.
Re-phase is fun but at first limit your corrections to broad "things" and don't try to fix every sharp peak and dip as the higher you go, the more likely these are spatially variable things past the voice coil and radiator which are not fixable globally speaking,
Hope that helps
Tom

[Mark Wilkinson]

Hi Mark
Try getting it as close as possible first without DSP and on that driver if i recall the mid needs to be inverted relative to the hf section and for a 6300Hz L&R 4th order xover, try delaying the hf about .2 to .18 ms with the crossover as the two sources are not perfectly aligned in time at the origin.  Fiddle with the frequency and delay a tiny bit to get as close to " one source" as you can, then apply the dsp as a final correction.
Re-phase is fun but at first limit your corrections to broad "things" and don't try to fix every sharp peak and dip as the higher you go, the more likely these are spatially variable things past the voice coil and radiator which are not fixable globally speaking,
Hope that helps
Tom

Thank you Tom,
Yes, that helps.  It's pretty much how I've been going about it... it's nice to sense some verification that I'm at least in the hunt

Using either 4th or 8th order linear-phase LR, I get 0.08 ms delay needed on the VHF coax section, along with polarity inversion. I'm guessing  the linear-phase crossover is what makes the difference between the time I get and your recollection. (Oh, I should have said I have the HE version... no idea if that effects timing.)

I hear your advice about broad strokes. It's easy to get tempted to do too much fine correction.... averages seem to be the cure, along with off-axis readings.
And I've kind of adopted the theory that when measurements don't change with corrections, I've run into stuff like the spatial variables you describe, stuff that needs a different cure.

Best,  Mark

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