[bill13]

Yes, I agree that I should start a new thread -- nee to think about what title it should have.

Anyway, my previous posts mentioned the following:  {attempting to include photos here...}
1. TC Sounds 18" Neo woofer mounted on 2x2 ft piece of plywood for measurements,
2. 3-Neo10 & RAAL OB experimental prototype (please excuse sloppy workmanship),
3. "16+16" (A3 drivers) line-array speaker with RAAL amorphous 140-15D tweeter -- note: felt waveguide for RAAL not shown in photo, duct tape used in photo (it works)--







This is first time for posting picts --  hope they will display OK.

Bill

[studiotech]

Alright, thanks Bill!  You really copied the look of the Audience loudspeakers.  And mine too....just bigger.  For a while I contemplated doing huge rounded edges like the Audience, but could not decide how to make that look right with the bamboo baffle, so I dropped that in favor of the largest reasonable sized roundover bit for a router.  Have you purchased the additional drivers for your enlarged version?  Are you attending RMAF this weekend to hear the new speakers from Danny?

I'm curious how you felt about the A3 drivers.  I wonder if they make a better midrange than tying to run those tiny things full range.  I don't care how much tech and throw a little driver has, IT'S TINY.  Too tiny to move any real air.  I heard several systems from Audience at shows in nice sized rooms, not the usual hotel suite and I was not generally impressed.  They didn't do too much wrong, but didn't seem to do anything special either and for the asking price, I want special.   

But then again, I've never really been a fan of single way, full-range driver systems.  I've never heard the so-called holy grail of "coherence".  I just hear piecing upper midrange, dynamically lacking bass response and in general, more problems than any lack of a crossover could ever fix.  I bought one of the Tang Band Lowther looking clones to try out as a midrange for this project.  Talk about an ear burner.  Ouch, even after steep filtering and EQing to be flat in it's intended passband, there was some nasty resonance coming through that just killed it.  I think there's a reason that fullrange fans seem to usually be part of the AARP crowd......just sayin'

Greg

[studiotech]

Anybody out there got a nice name for mine...I'm not too creative with stuff like that.  For now I just call it "BOB" for Bamboo Open Baffle.

[ratso]

it should be Bamboo Omnipotent Open Baffle

[bill13]

Greg,

Thank you for posting your 'Bamboo Open Baffle' thread - I have to give you credit where credit is due.   Your success inspired me to build the experimental 3-Neo10 version.  It would not have happened otherwise.

"Imitation is the sincerest form of flattery".  Yes, the 3-Neo10 version is essentially a realization of your concept (and of course, not beautiful craftsmanship like your bamboo OB speakers) ... but I always seem compelled {an audio hobby compulsion} to try making changes here and there - like adding an extra driver, &  try using a bigger woofer like the TC Sounds Neo 18", etc...

As for the Audience A3 speakers, it's a long story.  A couple of thoughts come to mind: When you drive 32 each A3s in the '16+16' speaker front and rear/side line-arrays (actually 30 A3s with the RAAL), the total effective 'cone' surface area is greater than that of a 15" woofer.   The A3 driver has a big Xmax so the comparison is somewhat justified.  I think maybe what limits the low bass output of the speaker is the somewhat high fs of each A3 driver and also the small moving mass with the typical rising output with increasing frequency (not sure, would have to do some theoretical analysis, etc.).  In addition, from a perfectionist point of view, evidently there's a problem with some apparent peaks in the frequency response of the A3 driver - most troublesome peak for me, so far, is an apparent peak roughly around 200 to 300 Hz --- my preliminary EQ attempt hasn't been successful yet. 
The A3 line-array (there's two line-arrays in each speaker) curved enclosure is now more of a "boffle" - that is, layers of fiberglass and felt are used for resistive acoustic loading of the A3 line-array's rear wave -- comparable to that achieved with so-called "boffle" or 'open-back' boxes. 
Despite shortcomings, the '16+16' A3-array's dynamics, low-level detail, and most of the midrange, are fantastic, I believe.  The RAAL ribbon gives a wonderful 'real-sounding' high end - and blends very well with the A3 drivers at a low 1600 Hz xover (24 dB per octave).

However, I'm building the Neo10 OB speakers with a goal of getting the 'open', non-resonant upper bass and lower midrange qualities of an open baffle.
Dan Richie's square four-Neo10 OB speakers now look like a candidate 'ultimate' approach to date (but IMO, substitute the Neo3 tweeter with the RAAL ribbon). 
I plan to use a higher crossover for the RAAL, like 2.5 - 3 kHz for the Neo10 OB speakers.

Thanks again for all your work.

Bill

[studiotech]

Bill, how did you wire your 3 neo10?  Using 4 works out great for a series/parallel pairing, but 3 of them?

I think you may find that mounting the Raal on its side requires you to move the foam pads a little closer together than the normal recommendation.  I felt like it worked better that way when I tried the prototype with all of the drivers flipped on their sides.   This will in turn, lower the level of the upper range and you may have to add a little boost.  Good measurements will make this simple.

Looking forward to your results.

[bill13]

The 3-Neo10s were wired in parallel resulting in a low impedance load.  For now, I'm using the new Hypex N-core power amps which can drive low Z.

Ordered another pair of Neo10s -- wiring the square four Neo10's in series/parallel will result in better load for amplifiers.  Another reason to go to the Dan Richie style four Neo10 'square' array.

Yes, horizontal mounting of the RAAL may present an EQ and a horizontal radiation pattern challenge, but will give it a try.   This new 4-Neo10 OB project is going to take some time....

Bill

[bill13]

Addendum:

Optimistically speaking, getting another pair of Neo10s appears to be ‘just can’t fail’ – using four Neo10s will succeed, one way or the other...   

If the ‘Dan Richie style’ 4-Neo10 OB {but with the horizontal RAAL instead of the custom Neo3 tweeter} just doesn't sound good enough,  then can simply stack the 4th Neo10 vertically and rewire in series/parallel.

Maybe initially evaluate/measure by mounting another vertically stacked Neo 10 {the 4th} above the top Neo10 on the existing 3-Neo10 experimental prototype (can attach another piece of plywood on the top of my 3-Neo10 baffle, and just leave the present vertical RAAL where it now is ).
Four vertically stacked Neo10s (40") may start to behave acoustically like a line-array with the SPL dropping off a bit slower with distance , etc..

The Bamboo baffles are great. 
Wish I had a CNC shop here for wood working, but perhaps that would be way too expensive, especially for my never-ending, evolutionary, experiments.   
Anyway, when watching movies and listening to music, the room is dark, so shouldn't be bothered by the poor DIY cosmetics.

Bill

[bill13]

Another addendum:

I would appreciate any suggestions & opinions about changing from the 15" woofer to an 18" woofer....

Am attaching a frequency response plot of my TC Sounds 18" Neo woofer (mic at 1.2 meter, 2X2 ft plywood mount).  This 18" woofer evidently is good from approx 70 Hz to say, 300+ Hz -- with only 5 or 6 DB EQ needed to use down to 70 Hz = target response.  Distortion below 300 Hz is much less than B&C 15" (distortion measurement not shown here).  Lower distortion is of course expected from this monster 53 lb driver with its very high power underhung radial Neodymium motor, 4" voice coil, and anti-flux-modulation shorting ring, etc.

Question is, do you agree this 18" woofer is a suitable candidate for crossing over to a four-Neo10 midrange at about 300 Hz ?  Or, must first mount it on my experimental OB speaker baffle, do some EQ, and do subjective listening tests, before expressing opinions?


Yes, perhaps I should start a new thread about doing four-Neo10s on an OB, but maybe no one would find it interesting - due to lack of focus & organization.

 Thanks,

Bill

[studiotech]

I'm doing my best cheerleader chant here, Ok?

New thread, new thread, new thread, Yaaaaaaaah!   Don't forget lots of pictures too.

I think there are many out there who would be interested in your projects.  That's why we're all here.

On paper, I question using the TC5100 up to 300Hz, but who can really know without listening and looking at distortion plots?  Try it, it might be killer.  And I think using 4 Neo10, you can drop the Xover to at least 200Hz, easy even at levels near 100dB SPL.  If you've got headroom on your EQ and front end, push more boost on the low end of the 5100 and get some real bass out of that sucker.  It can handle it for sure.  StigErik is using 21" drivers up to 200Hz with his RD-75 ribbon, and he's super duper critical, so I'd say go for it.  HAve you seen his mega thread over at DIYAudio?  Get something nice to drink and some free time and read through the whole thing to see his transformation from multiway, complex build to simple 2 way OB.

http://www.diyaudio.com/forums/multi-way/142015-my-open-baffle-dipole-beyma-tpl-150-a.html

PS, can we see the distortion plot?  Maybe a little larger for better detail?  Thanks.

[sfdoddsy]

Anybody out there got a nice name for mine...I'm not too creative with stuff like that.  For now I just call it "BOB" for Bamboo Open Baffle.

I'm afraid 'Bob' has been taken.



http://cargocollective.com/stevedodds/Revenge-of-the-Nerd

[studiotech]

Of course, how stupid of me!  How could I forget your Bobs.  Well, any other ideas?

[Russell Dawkins]

I'm afraid 'Bob' has been taken.



http://cargocollective.com/stevedodds/Revenge-of-the-Nerd

Interesting site!

[scorpion]

Regarding the name, why not  Greg's RAAL = (the holy) GRAAL. 

I side Greg in demanding bill to open a new thread for his venture.
Do test all different alternatives for the Neo10 orientation, horizontal, vertical and line. I doubt that RAAL horizontal is a hit.
Given Zaph's measurement on the Neo 10 I am a bit wondering about Danny Richie's horizontal placement even if he probably is crossing as low as 2 kHz.
It will be good to have Tyson's impressions from the RMAF.

/Erling

[JohnR]

Given Zaph's measurement on the Neo 10

Hi Erling, do you have a link to those handy? I can't find it.

[scorpion]

John,

The link is: http://www.zaphaudio.com/blog.html , thus in the blog part of the site.

Zaph's measurement procedure is outlined on the site here: http://www.zaphaudio.com/setup.html , discussing his SoundEasy application.

/Erling

[studiotech]

Hi Erling, do you have a link to those handy? I can't find it.

John, here's a link to my measurements.  They are quite close to Zaphs in spite of the fact that it is on my own baffle and under different circumstances.  Note that these are nearfield, so in room, listening position response is going to differ depending in baffle shape and size.  These are nice to get the basic idea of what's going one, but then you've got to back up and see what is happening to determine final Xover and EQ settings.

http://www.htguide.com/forum/showthread.php4?t=37264&highlight=neo10

Greg

[scorpion]

BG Radia's own measurements of the new Neo8S (developed along the lines of Neo10) driver's horizontal and vertical dispersion is perhaps of some interest here:
http://meniscusaudio.com/images/NEO8S-spec%20sheet%20Rev1.pdf .

/Erling

[studiotech]

If you guys are really interested in off axis response of the Neo 10's in an actual application then I will try to post you some data as soon as I can.

If you're offering, we're looking.  I've got my own, but now I wanna see yours.

[Danny Richie]

If you're offering, we're looking.  I've got my own, but now I wanna see yours.

Okay, I will try to get you some this weekend.