The Megaliths open baffle line array speakers

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The Megaliths open baffle line array speakers
« on: 30 Apr 2016, 02:26 pm »
Today begins the next stage of the open baffle line arrays.

After the ideas learned from the Pulsing Quasar FPS drivers, it's time to scale it up.

The new speaker will be called The Megaliths. Here is a picture of the open baffle speaker wood at the builders facility. Going for a test fit of drivers today.

To start it will be 8 - BG Neo10 planar drivers per side, each with it's own amp module as before with the FPS drivers. The beamformer will be used again along with Math Audio Room EQ and the dspMusik to build the digital crossover and EQ needed to run them full range.

The baffle is the side wing concept also used on the FPS line array with the piano hinge for angle set and stability.




S Clark

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Re: The Megaliths open baffle line array speakers
« Reply #1 on: 30 Apr 2016, 08:04 pm »
The baffle is the side wing concept also used on the FPS line array with the piano hinge for angle set and stability.


That is basically what one of my students did with his line array project many years back.



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Re: The Megaliths open baffle line array speakers
« Reply #2 on: 30 Apr 2016, 08:24 pm »
Scott,

Cool!  Looks like the only difference is the side wing addition.

I am just glad that I can do this with the BG Neo10's.  Luckily I found 16 NOS units to get.

Now if PE would get the BG Neo3-PDR's would be all set.

S Clark

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Re: The Megaliths open baffle line array speakers
« Reply #3 on: 30 Apr 2016, 09:08 pm »
You can't really see his wings, but he had wings on either side on long piano hinges.  We moved them around to find the best measurements.  He and I took it up to Danny to get the crossover really dialed in.  Honestly, it sounded pretty dang good, and very innovative for a 17 year old in 2007.

Avoosl

Re: The Megaliths open baffle line array speakers
« Reply #4 on: 30 Apr 2016, 09:09 pm »
Rich,

     There are probably more people out there excited about this than you think.  They're probably hesitating,
holding their breath, and wondering, "Can he really pull this stunt to completion?"  - a 21st Century improvement
to the venerable Infinity IRS megalithic towers?  Well, I have confidence, Rich. 

     By the way, I like the Megalith name, but I think it merits a subtitle descriptive of its significant factors.  How about,

                           Megalith - the Digital Beamforming Distributed Power Line Array

The acronym DBDPLA is not pronounceable or memorable to earthlings, but the full-out spelling catches the eye.
What do you think?  The Digital Beamforming deserves accolades by itself, as well as the distribution of power
amplifiers.  Not to mention the active digital crossover with various corrective engines.  It is possibly too far beyond
what most audiophile are thinking about to fully appreciate.  But, just wait, and all the doubters will be shaking and
ratttling their bones at the curious megalithic object standing before their astonished senses.
till they hear it.

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Re: The Megaliths open baffle line array speakers
« Reply #5 on: 30 Apr 2016, 09:23 pm »
Avoosl,
I think it will be very interesting hearing these with the 6x12 servo subs in my room.  If the Pulsing Quasar's outcome is any indication, these should be very interesting indeed.

I like your explanation!  That will be the new Megalith description for hence forth!  :thumb:

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Re: The Megaliths open baffle line array speakers
« Reply #6 on: 30 Apr 2016, 09:26 pm »
Scott,
Very cool indeed!  I think the wing idea works very well! 

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Re: The Megaliths open baffle line array speakers
« Reply #7 on: 1 May 2016, 05:50 pm »
Well I will ask this of the general reading audience, is there any reason to continue this build thread? 

I see people viewing it, but only three people have commented.   :scratch:

If no interest into what happens, will just drop it and go back to building MS-3 Music Server PC's with the room and speaker correction software.

SoCalWJS

Re: The Megaliths open baffle line array speakers
« Reply #8 on: 1 May 2016, 07:48 pm »
Well I will ask this of the general reading audience, is there any reason to continue this build thread? 

I see people viewing it, but only three people have commented.   :scratch:

If no interest into what happens, will just drop it and go back to building MS-3 Music Server PC's with the room and speaker correction software.
Rich - Not enough info for me to comment on at this point. Always interested in new OB builds (I drool over some of Danny's stuff that will probably never see the light of day  :( ).

What are you pairing the Neo10's up with? (an assumption on my part that they won't be "full range")

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Re: The Megaliths open baffle line array speakers
« Reply #9 on: 1 May 2016, 08:00 pm »
SoCalWJS,
To start with they will be full range with just the BG Neo10's.  That is why I am using Math Audio Room EQ. 

Even with the correction, the sensitivity of the Neo10 array should be close to 100dBSPL/1w/1m and -3dB at 20KHz.  All planar drivers have their own amp modules.


Tyson

Re: The Megaliths open baffle line array speakers
« Reply #10 on: 1 May 2016, 08:02 pm »
Looks cool!  How are you going to deal with the beaming that happens to the 10's high frequencies?  Or is that a feature and not a bug in this design?

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Re: The Megaliths open baffle line array speakers
« Reply #11 on: 1 May 2016, 08:07 pm »
It will be part of the design.  Since there is a time domain beamformer working to make a vertical beam and keep the sidelobes down, we will see what happens.

I tested the idea on the smaller FPS planar drivers in the Pulsing Quasar design I did earlier and it sounded very good.

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Re: The Megaliths open baffle line array speakers
« Reply #12 on: 1 May 2016, 08:15 pm »
To give everyone an idea of what I am discussing, this is a variant of ideas used by Quad on the ESL63 speakers and used in SONAR acoustics.  They did concentric rings for the electrostatic speaker with miles of wire for the time delays.  With the dspMusik digital crossover, there is full time delay capability for each output channel.

Not only are pairs of the planars going to have different delays, but the servo sub array will be time aligned as well, so all four output channels will have different delays as part of the processing.  Very difficult to do with analog crossovers using all pass filters and coil delays. 

 

TomS

Re: The Megaliths open baffle line array speakers
« Reply #13 on: 1 May 2016, 10:19 pm »
To give everyone an idea of what I am discussing, this is a variant of ideas used by Quad on the ESL63 speakers and used in SONAR acoustics ...
Something you know just a wee bit about  8)

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Re: The Megaliths open baffle line array speakers
« Reply #14 on: 1 May 2016, 10:30 pm »
Well maybe just a bit.

It was in my Sonar Processing 101 class book about 30 years ago.

nickd

Re: The Megaliths open baffle line array speakers
« Reply #15 on: 1 May 2016, 10:49 pm »
Rich,
Watching  :D

I have built curved arrays before and use Neo 10's for mids (450-1500 hz) in my current reference system.

The drivers are amazing indeed. Most transparent midrange for the money I think. It's ashamed they are now extinct.

Just not sure how I feel about beaming. I remember hearing a Bongiorno design a few years before he passed. I sat between the speakers in a "sweet spot" and dang, best imaging ever. Moved my head to tell my buddy how awesome it was and the soundstage collapsed. The "beam"  was for one person only. Neat trick, but I don't think there was any commercial interest.

I have always preferred wide dispersion designs I suppose. just like the freedom to move around I suppose.
Nick

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Re: The Megaliths open baffle line array speakers
« Reply #16 on: 1 May 2016, 11:12 pm »
Christie Digital now sells the BG planars to Parts Express and you can buy them again.  They also have the Neo3-PDR's as well.

I have some Neo3-PDR's on order when they get stock in a few months.

I have been using the Neo10 in the open baffle two way and do not have the horizontal beaming issues up to 7KHz.  Will see what happens when I extend the range to 20KHz. 

I am no woodworker, so a curved planar array was well outside my idea range.  I think it will be easier with the planar array and DSP processing instead.  So far that has worked well in the FPS planar arrays I built.  Put the vertical beam on the center axis and wide enough to move your head around.  They are much smaller than the Neo10's, so will see how it goes.  If to narrow, will add the Neo3-PDR's for the tweeter range.

The baffle is setup to mount both, just do not have them until PE gets stock.

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Re: The Megaliths open baffle line array speakers
« Reply #17 on: 2 May 2016, 10:31 am »
For power conditioning to run the 16 amp channels, asked Dave Elledge to build a buss.  He is calling this one the BlunderBUSS with 24 AC outlets.  Love that name!   If I add the tweeter array will need 20 AC sockets for the amps.  The other 4 are for the dspMusik and the HX800 servo amps. 

The MS-3 Music Server is on it's own DigiBUSS, and will use my original UberBUSS to drive DigiBUSS as Dave suggests once the BlunderBUSS arrives. 

Cut 16 new Belden 1309A speaker cables for the Neo10 drivers and started prepping them for connectors.  Waiting on the 0.187" 16-14 Fast-On's to arrive to crimp on the cables for the Neo10's.

All the 16 modified LM3875 Gainclone amps are built with balanced inputs and DC coupled signal path.  DC offset is less than 10mV DC for every module driven by the dspMusik that is also DC coupled.  The amps do not have either a Zobel or Theil network on the output, as they are totally stable into the nearly resistive load of the BG drivers as tested.  The speaker cables themselves are the only inductance/resistance needed for stability.

Hopefully will be picking up the finished baffles this Saturday and start building the speakers with the BG Neo10's and wiring them up for testing.

Guy 13

Re: The Megaliths open baffle line array speakers
« Reply #18 on: 2 May 2016, 10:58 am »
Hi,
up to now, I did not comment your topic,
however, I did read every one of your post.
I find it interesting and I like the pictures that
makes that topic of yours even more interesting.
Thanks for sharing your project.
If I did not asked any questions,
it's because it's pretty self explanatory.  :thumb:
Thanks again for sharing.

Guy 13

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Re: The Megaliths open baffle line array speakers
« Reply #19 on: 2 May 2016, 11:07 am »
Guy 13,
Thanks for the feedback!  Glad you found it interesting and followed the process easily. 

I am not a great writer, so good to hear it is clearly written.