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[John L Nobile]

Presonus has come out with a box that has a 12" "woofer" and 8 - 2" speakers which they claim is a line array meets point source system. I don't know who they're marketing this to but it's not me.

I can't keep up with all the new speaker systems coming out in the last few years. It reminds me of the synth explosion in the 80's.

[Chris Hindle]

Presonus has come out with a box that has a 12" "woofer" and 8 - 2" speakers which they claim is a line array meets point source system. I don't know who they're marketing this to but it's not me.

I can't keep up with all the new speaker systems coming out in the last few years. It reminds me of the synth explosion in the 80's.

Bose Bloze ? 
Chris.

[Brian Jojade]

Are you in the market to buy new speakers?  If not, then it doesn't matter.  Yeah, there's always going to be new twists and turns on equipment.  Sometimes it's better, sometimes it's not.

We've gotten to a point where there's no real continuity in products out there.  For any application, there could be thousands of products that could be put in that could do the job, and of those, there are many different designs that could do the job well. (There are also a ton of designs that certainly won't be good choices)

The lifecycle of a product being the latest tech is also shortening.  It used to be that you put in a sound system and that model was around for 5 or more years.  Now, the model of speaker you put in will only be available to purchase until next Thursday....

For pro sound, there's really only a couple of questions that need to be asked.  1. Can this new product make me money? 2. Can this new product make my job easier?  Pretty much if you can answer yes to both of those questions, then it's worth considering.  If not, then continue on your way.

[Stephen Kirby]

Driver design and performance has made leaps and bounds in the last few years.  While a strip of 2" drivers isn't a line array, it may do things far beyond what you expect.

[Chrysander 'C.R.' Young]

I just checked the system out on the web site and they very scrupulous never claim to be a line array.

[Nathan Riddle]

I just checked the system out on the web site and they very scrupulous never claim to be a line array.

Except in their video.
https://youtu.be/cyq4l5E6qJM

[Art Welter]

Presonus has come out with a box that has a 12" "woofer" and 8 - 2" speakers which they claim is a line array meets point source system. I don't know who they're marketing this to but it's not me.

I can't keep up with all the new speaker systems coming out in the last few years. It reminds me of the synth explosion in the 80's.

John,

The CBT array concept is not exactly new:

D. B. Keele, Jr., “The Application of Broadband Constant Beamwidth Transducer (CBT) Theory to Loudspeaker Arrays,” 109th Convention of the Audio Engineering Society, Preprint 5216 (Sept. 2000).

CBT theory wasn't exactly new 18 years ago either, but it takes a while for even Keele to spin a few heads.
His “What’s So Sacred About Exponential Horns” came out in 1975, but exponential horns have not gone away.
 
As Stephen Kirby points out, today's better 2" cone drivers ain't what were put in transistor radios in the 1960's ;^).
Cone driver HF have some advantages over compression driver/line array HF horn designs, but like every other "solution" won't solve every equation.

Art

[Gordon Brinton]

I have yet to hear a mini line array that sounds natural and full-bodied like a conventional box speaker. To me, they just seem to sound slightly mechanical, cold, shrilly, and unbalanced across the frequency spectrum. Perhaps it's their lack of sizable mid and low-mid drivers or their overabundance of upper-mid. Maybe this one is different, but I am not holding my breath.

[Nathan Riddle]

Linky,

https://www.presonus.com/products/CDL-Loudspeakers

What effective pattern control does it have?

420Hz crossover = 32" or 8" 1/4 so I can see the woofer aligning with the 2" drivers.

2" spacing between centers of drivers = ~3300 Hz 1/4 wavelength means pattern control for 3kHz up?

Did I do my math correctly?

[Art Welter]

Linky,

https://www.presonus.com/products/CDL-Loudspeakers

What effective pattern control does it have?

Nathan,

The "math" to determine the effective pattern control of a CDL array is a bit more complicated than a few 1/4 wave calculations.

As in any line array, each addition of another element affects the pattern control.

Keele's predictions for 1 to 6 boxes (attached) are probably "close enough for rock & roll"  .

Art

[Nathan Riddle]

Nathan,

The "math" to determine the effective pattern control of a CDL array is a bit more complicated than a few 1/4 wave calculations.

As in any line array, each addition of another element affects the pattern control.

Keele's predictions for 1 to 6 boxes (attached) are probably "close enough for rock & roll"  .

Art

Well that's why I'm here, to learn

Is the 'box count' the same as driver count?
Does the box/driver predictions take into account physical size?

[Art Welter]

Well that's why I'm here, to learn

Is the 'box count' the same as driver count?
Does the box/driver predictions take into account physical size?

Each box has 8 HF drivers in a curved array, the predictions taking into account physical size and shading.

You can read all about it:

"Based on the Constant-Directivity Two-Way Loudspeaker System design presented at the 143rd AES Convention in New York by Hugh Sarvis and Don Keele"

https://pae-web.presonusmusic.com/downloads/products/pdf/AES_143__eBrief_188_V1-_Keele_Sarvis_-_Design_and_Implementation_of_a_CD_Two-Way_12__Woofer_Wedge_Loudspeaker_System.pdf

[Nathan Riddle]

Each box has 8 HF drivers in a curved array, the predictions taking into account physical size and shading.

You can read all about it:

"Based on the Constant-Directivity Two-Way Loudspeaker System design presented at the 143rd AES Convention in New York by Hugh Sarvis and Don Keele"

https://pae-web.presonusmusic.com/downloads/products/pdf/AES_143__eBrief_188_V1-_Keele_Sarvis_-_Design_and_Implementation_of_a_CD_Two-Way_12__Woofer_Wedge_Loudspeaker_System.pdf

Wow, that is literally the paper on how they built the unit. It performs better than I expected. Nice job Presonus.

I wasn't far off with my 3kHz calculation though.

[John L Nobile]

Each box has 8 HF drivers in a curved array, the predictions taking into account physical size and shading.

You can read all about it:

"Based on the Constant-Directivity Two-Way Loudspeaker System design presented at the 143rd AES Convention in New York by Hugh Sarvis and Don Keele"

https://pae-web.presonusmusic.com/downloads/products/pdf/AES_143__eBrief_188_V1-_Keele_Sarvis_-_Design_and_Implementation_of_a_CD_Two-Way_12__Woofer_Wedge_Loudspeaker_System.pdf

Very interesting. I didn't realize that this was where Presonus got the inspiration. Thanks for clearing that up for me Art. My head stopped spinning.

[Chris Grimshaw]

... and in the end, we're still waving bits of cardboard around with magnets.

Chris

[Stephen Kirby]

There's still a long way to go, especially in SR.  Look at how much bottom and level comes out of those little bluetooth speakers.  Apple has a patent on a system for capacitively sensing the position of the diaphragm and applying various limiting schemes to keep it within excursion limits.  Thus maximizing the amount of level you can get out of a small device.  Such amazing things you can do with computers these days.

[Rory Buszka]

Wow, that is literally the paper on how they built the unit. It performs better than I expected. Nice job Presonus.

I wasn't far off with my 3kHz calculation though.

It is clever how Don Keele and Hugh Sarvis (WorxAudio) developed this concept to incorporate the only unclaimed embodiment of a Constant-Beamwidth Transducer (CBT) array in Keele's earlier patent US7826622B2 by placing the attenuation circuit upstream of individual amplifier sections that subdivide the circular-arc array of wideband drivers. Otherwise they might expect to have infringed on the earlier CBT patent. Directivity and level shaded arrays of line array cabinets have already been proposed, where any level shading is provided upstream of the power amplifier rather than being integral to the speaker. The Keele patent claims an array speaker with level shading networks provided between the input terminals and the speaker itself, rather than ahead of an integrated power amplifier, according to my reading.

In the earliest presentation I attended where Don Keele and Marshall Kay presented the curved CBT36 speaker, Don commented that after spending his entire career working on improvements to horn technology, he now saw small drivers as being capable enough to work together in an array that would be more compact than a horn and replace horns in many applications. The circular-arc CBT in particular is intended to replace a single large horn in systems where wide horizontal dispersion is needed, and the vertical coverage angle can be subtended between the extents of the circular arc array.

The Bose F1 812 is an example of another system where a traditional high frequency horn is replaced by twelve (Tymphany-made) 2-1/2" cone drivers, and a 12" driver is placed behind the array. Calling this a "coaxial" approach is not strictly accurate because the system is not axisymmetric. In my own hearing of the Bose F1 812 system at a WFX speaker demo event, I found the array of full-range drivers to have a "softer" sound characteristic, probably due to some power compression and additional mechanical compression (driver break-up), but in certain applications like a medium-throw auditorium installation, this characteristic could be desirable to avoid sounding "piercing", but these cabinets should present no great risk to the medium format line arrays of the world. I think it would be reasonable to expect the Presonus array to have a similar characteristic. For installation purposes, I would have hoped for a full-face grille rather than the partially perforated panels on either side of the central array for a cleaner look, but there is probably time for Presonus to revise their product in a later version.

[Scott Holtzman]

... and in the end, we're still waving bits of cardboard around with magnets.

Chris

and Kevlar

[Marjan Milosevic]

Dynacord did that decades ago.

[Marjan Milosevic]

JBL too

[Rory Buszka]

JBL too

Given that the Presonus development between Don Keele and WorxAudio's Hugh Sarvis is intended to produce a circular-arc array with constant vertical beamwidth, it is conceptually closer to the JBL CBT (which is also Keele's patent, though it narrowly focuses on passively filtered systems) but the Dynacord Cobra looks similar in that it places a line of midrange drivers in front of a 12" woofer. (Arguably this is a marginal approach because it does little to nothing to address internal reflections from the midrange drivers, only the HF section). Where the Presonus product diverges from the Dynacord product is it uses a circular-arc array shape (not a line array) and no compression HF, and where the Presonus product diverges from the JBL patent is its use of active filtering settings between discrete cabinets to produce the array behavior with constant vertical directivity.

[ProSoundWeb Community]