New Home for the BG Ribbons - Part 27

[Hank]

In addition he's going to experiment with having an air gap between the RD50 and midbass panels.

Why - to keep any woofer baffle vibration from the RD's? How about one baffle for both and mount the woofs from the rear without screws, using a brace to hold them against the baffles like some designs have done? Using good quality gasket material of course.

[ThomasW]

Why -to keep any woofer baffle vibration from the RD's?

No he wants the sound to go into the gap instead of interacting with the baffle.

[JonMarsh]

I don't recognize those planar elements.....?

Newform ribbons, I'd hazard....

Nice going Craig! :T :T :T

Don't let Mr. T pick on you.... :rofl:

[JonMarsh]

No he wants the sound to go into the gap instead of interacting with the baffle.

Most especially, a midwoofer setup would really "pump" a dipole ribbon midrange or tweeter with a continuous panel- if they're disconnected, then the old side null applies.

[CraigJ]

klone the Excelarray. Boooooo. Something about the looks of that dildo standing next to a box thing really bugs me. If it were me, I'd go open baffle and build the ribbon into the baffle, crowding it as close as possible to the woofs. More work but it should both look and sound better.......Looking good, Craig! So that's a monopole Newform planar with dipole mids and woofers?

Thanks Dennis,

You either have a very good memory, or are a good detective. As you can see, I did take your advice and used Thomas's older RD75 baffle design. Hank, what about 6 Aurasound NS10 per side with one RD75?

Craig
p.s. you aren't the only one here keeping an eye on their parents.

[CraigJ]

Newform ribbons, I'd hazard....

Nice going Craig! :T :T :T

Don't let Mr. T pick on you.... :rofl:

O.K., lets see how that check list of dipole builds while Jon is gone is coming;

-finish Isiris Jr. - done
-finish Saint Saens- done
-finish Phoenix - done
-seek professional help from "speakers anonymous" - not done, next project?

Welcome back!
Craig

Jon wrote, "if they're disconnected, then the old side null applies", guess that's why I left my gap. :W

[ThomasW]

Hank, what about 6 Aurasound NS10 per side with one RD75?

A lot of wasted Vd unless one's planning on EQing them to run really, really, low. With my old original black baffles with the 8" Eton's, they were barely off idle given the comparatively low output of the planar elements

[CraigJ]

Craig, let's see the back of those beauties! ;x( I'm curious how you hold them up.

John,
Here you go:

[ThomasW]

Bigger image...

[Hank]

Most especially, a midwoofer setup would really "pump" a dipole ribbon midrange or tweeter with a continuous panel- if they're disconnected, then the old side null applies.

Whoa! Look who yanked his arm hard enough to break the chain to his job desk so he could type a few words! Is it the professor himself? I've been worried about your mental/physical health with your job absorption - the world of commercial high tech is brutal - I'm there :-(
So, two separate baffels, eh? What gap width between them?

[JonMarsh]

Whoa! Look who yanked his arm hard enough to break the chain to his job desk so he could type a few words! Is it the professor himself? I've been worried about your mental/physical health with your job absorption - the world of commercial high tech is brutal - I'm there :-(
So, two separate baffels, eh? What gap width between them?

Ola Hank!

The only sliver lining of the current economic conditions is that my management wants the books to look better, and lower costs, so now they're encouraging me to take some time off- will be at 75% duty the next few months. Would rather do 50% myself.... Just got back from two weeks on the road, trying to wrap things up at work to take the following week off with a "clear conscience". ;^)

What gap between them is a good question- a little experimentation so far shows that 2-3" is probably the minimum. But we'll see. I've got some Corian baffles I'm pondering using for part of the Saint-Saens, but that will be later this year at the earliest, as there are a couple of other "little" projects ahead of it, including a two piecer using the NHT sat module and hopefully a Duelund type crossover. And then there's the partially constructed/designed M12ta, and the nascent Indra Klone (NOT using any Accuton drivers). (let's not even go near the convertion of the M8ta from a two way to three way).

Obviously, I need to prioritize, or I need an Intel style Sabbatical. I don't know if either are possible, the latter is pretty dang unlikely!!

For that matter, I'm looking at a Duelund for the Saint-Saens, too- you know, the rabbit may be "Crazy for Coco Puffs", I've gone "Gaga for Duelund".

This is the target transfer function for the Indra Klone, center frequency of 1 kHz and aleph of 2.5.



The cyan line indicates the level at which I think the drivers must track well for it to all add up; done correctly, the drivers are in the same relative phase through out that bandwidth. OTOH, another way of looking at it, is that for it to work correctly, the drivers MUST BE in the same relative phase from 200 Hz to 6 kHz for this to sum correctly. But it was pulled off OK in the NeoD CC after some work, and I think it's even more doable in this project.

BTW, this is an obvious (to me) candidate approach for the BG ribbons, as they go low, but won't play all that loud down low- a sort of prefect recipe for a Duelund approach, as output is reduced by -20 dB compared with reference level, which in this case lies in the frequency range that the BG's excel at. I expect to use a very similar target for the Saint-Saens.

We'll see how the "Indra Klone" and M12ta go; parts either here or an the way already. Not too expensive, except for the tweeter, and if you have to ask, it's too much.

~Jon

[CraigJ]

Jon,

And to take Tim's thread even further off track....Just when I was about to build "my version" of the M12ta,



You mention the "Indra Klone", I'm in! Reminds me of Paul Ebert's beautiful Trillium speaker.

Craig

[Dennis H]

For that matter, I'm looking at a Duelund for the Saint-Saens, too- you know, the rabbit may be "Crazy for Coco Puffs", I've gone "Gaga for Duelund".

This is the target transfer function for the Indra Klone, center frequency of 1 kHz and aleph of 2.5.

Hey Jon, good to see you back!

If you want to try my ghetto/redneck Duelund thing, that works out to LR2 filters at about 500 and 2K.

-------------------------------

Duelund 3-way with f=1000 and a=2.5
LspCAD optimization from 30-16K, error =~ .002dB

Woofer: LR2 lowpass @ 499.9 + LR2 lowpass @ 2000.4
Mid: LR2 highpass @ 499.8 + LR2 lowpass @ 2000.7
Tweeter: LR2 highpass @ 499.9 + LR2 highpass @ 2000.3

Most likely the slight differences are due to the target files only having .01dB precision.

Edit: yup that was it. I increased the resolution of the target files to 4 decimals and that put all the frequencies within .1 Hz on the optimization runs and dropped the error to ~.0007dB. Not that it matters, just having fun with numbers. :P

[mkc]

Hi,

My first post to the board.

I would like to direct your attention to the following web page.

http://pro.speakerbuilder.dk/synkron/

Here you can generate target files.

The wording is in danish at the moment, but I'm sure you can figure it out. I will try to talk to the web-site owner anf get the wording change to english.

A 4-way Duelund calculator has also been made, but not uploaded yet.

Best regards,
mkc

Edit by moderator to add link using Google translate

http://translate.google.com/translate?prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fpro.speakerbuilder.dk%2Fsynkron%2F&sl=da&tl=en&history_state0=

[JonMarsh]

Hey Jon, good to see you back!

If you want to try my ghetto/redneck Duelund thing, that works out to LR2 filters at about 500 and 2K.

-------------------------------

Duelund 3-way with f=1000 and a=2.5
LspCAD optimization from 30-16K, error =~ .002dB

Woofer: LR2 lowpass @ 499.9 + LR2 lowpass @ 2000.4
Mid: LR2 highpass @ 499.8 + LR2 lowpass @ 2000.7
Tweeter: LR2 highpass @ 499.9 + LR2 highpass @ 2000.3

Most likely the slight differences are due to the target files only having .01dB precision.

Edit: yup that was it. I increased the resolution of the target files to 4 decimals and that put all the frequencies within .1 Hz on the optimization runs and dropped the error to ~.0007dB. Not that it matters, just having fun with numbers. :P

Now, let's see any of us get within two orders of magnitude of accuracy with real drivers and crossovers!!! :rofl:

But if you keep in mind the main concept and benefit- a single all pass like phase rollover with relatively low group delay, and phase tracking enough to achieve the expected summation in the midrange, you just may wind up with something nice to listen to. :T

[JonMarsh]

Hi,

My first post to the board.

I would like to direct your attention to the following web page.

http://pro.speakerbuilder.dk/synkron/

Here you can generate target files.

The wording is in danish at the moment, but I'm sure you can figure it out. I will try to talk to the web-site owner anf get the wording change to english.

A 4-way Duelund calculator has also been made, but not uploaded yet.

Best regards,
mkc

Edit by moderator to add link using Google translate
http://translate.google.com/translate?prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fpro.speakerbuilder.dk%2Fsynkron %2 F&sl=da&tl=en&history_state0=

It's in English when I just tried it this afternoon! Thanks for the link and to the gentlemen putting in this effort!





I won't toss away my MathCAD files, but this can be a big help to others wanting to experiment. :T

[JonMarsh]

Jon,

And to take Tim's thread even further off track....Just when I was about to build "my version" of the M12ta,



You mention the "Indra Klone", I'm in! Reminds me of Paul Ebert's beautiful Trillium speaker.

Craig

Are we talking about the same "Indra", as in by Avalon?





Image not available

Just checking, as I have no idea what Paul's Trillium looks like. ops:

[Dennis H]

Now, let's see any of us get within two orders of magnitude of accuracy with real drivers and crossovers!!! :rofl:

But if you keep in mind the main concept and benefit- a single all pass like phase rollover with relatively low group delay, and phase tracking enough to achieve the expected summation in the midrange, you just may wind up with something nice to listen to. :T

Yeah, keeping it real, we won't get anywhere close with real drivers. But I'm into simple concepts a redneck can understand and S-plane math makes my head hurt. The stacked LR2 thing works with any real 3-way (or 4-way). It's what my old prof used to call 'elegant' -- easy to get a mental picture of an LR2 highpass and an LR2 lowpass giving the same phase rotation. I tested it down to a=2 where there's only about a 10% spread (f1=950, f2=1050) and it still works there. Below there, it starts to fall apart as the Duelund equations reduce down to an LR4 2-way at a=1.414 and don't work at all below 1.414.

[CraigJ]

Are we talking about the same "Indra", as in by Avalon?

Yes, and I just completed course 101 in multi-facet veneering for the "big" project. Oh, and I would not recommend the inexpensive and super thin veneer that Menards/HD sells. May even get to build my second crossover without the help from Madisound.



Craig

[JonMarsh]

Looks pretty good, Craig! It is a challenge. Do you have a Rockler Store anywhere within reasonable (or unreasonable) driving distance? They have a lot of wood resources, and it's where I get all my hardwoods and veneer (in Pleasant Hill, about 35 miles from home).

[CraigJ]

Do you have a Rockler Store anywhere within reasonable (or unreasonable) driving distance?

Jon, The multi-faceted Phoenix/NaO project was an experiment using only "leftover" parts (except plumbing parts ). I didn't want to spend a lot of money on finishing, since there was a chance it might end up in a closet. Usually, as in the case of my "Saint-Saens"., I purchase my veneer from Tape-Ease.

Again, welcome back!

Craig

[Hank]

Jon said:

a single all pass like phase rollover with relatively low group delay, and phase tracking enough to achieve the expected summation in the midrange, you just may wind up with something nice to listen to.

:agree: ;b> : :banana: :^x

Thomas, I just called madisound and the Peerless Nomex 830875 you like will be in stock in about a month at $54.30.

[pusle]

Active 4-way system and woofer selection

Hi

I'm a fan of the NEO3pdr as I've used it in an open baffle design I built about 5 years ago. It also had a 4.5inch seas mid-range and 8x 8" audax woofers pr channel. The sound was dynamic and good for live recordings and movies, but overall not that great.

I'm planning a new system now which will try to take a "best of several worlds" approach. Filter will be digital, maybe 4th order roll-off but phase linear, with time-alignment etc. Nothing between the amplifiers and the speaker terminals but wire. Here is a run down of the system, 1channel:

Tweeter : 1x NEO3pdr , 1250Hz - 20000Hz
Mid-range : 1x NEO8 , 300HZ - 1250Hz
Bass : 2x RS180 ? , 80Hz - 300Hz
Sub : 2x L26roy , 20Hz - 80Hz

All drivers will be in sealed enclosures with digital correction for the sub. I'm thinking of maybe going bipolar, with additional rear mounted bass/mid/tweeter.
Cabinet will be about 20cm wide, and 120-140cm tall, except at the bottom where it flares out to make room for the two 10" Seas on each side of the cabinet.

The choice of x-over freq is based on the notion that I don't want any nulls. As it is now there are about 6dB reduction +/-90Deg off axis when all the elements are spaced as close as possible (except the sub). In practice there will be a null at higher freqs, but what can you do..

My main question is about the woofer choice. The RS180 looks good on measurements I've seen. It's not too expensive, but will it sonically match the two Neo elements? Is there some other elements that would make a better match? I guess a tight waterfall diagram is the thing to look for?

How about the overall design? I am worried that maybe there is not enough area especially for the woofer, and perhaps should throw in more of them.
Since I'm choosing sealed, the volume needed pr driver must be small...
The same goes for Neo's too, but I do want it to be as close to a spherical radiation pattern as possible, and this excludes using more neo8's and neo'3s

Any suggestions are greatly appreciated

-Pusle

[Hank]

Hi and welcome, Pusle! I suggest you start a separate thread with your post. This thread is really about line arrays, particularly LA's based on the B-G RD 50/75. You'll get plenty of helpful comments on this forum.

[CraigJ]

A bit higher on the food chain is the very nice Peerless Nomex 830875. These are among the most 'neutral' sounding drivers I've heard....
http://www.madisound.com/catalog/pro...oducts_id=1613

If anyone is interested, these drivers are on "buyout" at PE in the $27 range.

Craig

edit; apparently I can't read prices.

[JonMarsh]

Thomas is interested... just got an email from him.

[Hank]

If anyone is interested, these drivers are on "buyout" at PE for $20 each

Whoa! So, Madisound just got a new shipment in and they're $54.30 ea/ $48.87 for 10+, BUT PE has them as a buyout? Normally that means they're discontinued by the mfgr...hmmm...
Anyway, I am interested too.

[ThomasW]

Hank,

Get them ASAP.

I talked with PE yesterday they had a total of ~approx 150 pcs. And someone you know ordered 32 of those.....

[JonMarsh]

Greedy little guy, aren't you? :W

I feel like I'm splurging when I go out and order four 7" drivers, as I did on Monday... :B

[Hank]

Wow - 32? 16 per side? You must be going for the RD75 - I'm just not convinced I need that vertical coverage. Convince me already - otherwise it's the RD50.

Point: if these really are factory discontinued, it might be smart to order a spare or two.

[ThomasW]

I'm using 12/side with RD75's, the other 8 are for a different project.

8/side is fine for RD50's

If you want to get any of these pull the trigger SOON because I just ordered 24 for Chasw98.... plus 6 spares.....that gets the free shipping on a wholesale account.

[Bear]

If anyone is interested, these drivers are on "buyout" at PE for $20 each.

Craig

Up to $27/ea. in quantity now. Seems PE sensed a bit of a "run" on these.

Bill

[ThomasW]

Craig's $20 was a typo or he rounds off a little differently than most people.....

The retail pricing hasn't changed, $32.80 or $27.66 4+

[chasw98]

Greedy little guy, aren't you? :W

I feel like I'm splurging when I go out and order four 7" drivers, as I did on Monday... :B

Yeah, I felt like a high roller today when at the end of the day I had a reason to find a hiding place in the house for 24 of these buggers! Going shopping with Thomas is fun! :T :E

[chasw98]

Most especially, a midwoofer setup would really "pump" a dipole ribbon midrange or tweeter with a continuous panel- if they're disconnected, then the old side null applies.

Jon:
Can you explain this in further detail as far as determinig how wide the gap should be and pitfalls to look for in design or just a plain old rule of thumb?

Chuck

[JonMarsh]

I've only experimented with this in a somewhat casual kind of way; i.e., looking at low frequency component with a dipole woofer panel putting the mic at a midrange driver, and separating the panels until the level drops off significantly; 2-3 inches seems to be about the minimum. My concern is my older Fountek ribbons, which are NOT mounted in plastic, and can be damaged even by blowing on them. An RD panel, which has a relatively stiff plastic membrane involved, I don't think this is an issue to worry about. High compliance mids or tweeters, I think they'll act like a microphone if on a continuous panel- in fact, that's the easiest way to measure the effect. Using a separate measurement microphone it's easier to quantify the fall off in SPL.

[1Michael]

QUOTE]Yeah, I felt like a high roller today when at the end of the day I had a reason to find a hiding place in the house for 24 of these buggers![/QUOTE]
Must of been a big hiding place to fit 24 of me :E :rofl:

[JonMarsh]

Yeah, I felt like a high roller today when at the end of the day I had a reason to find a hiding place in the house for 24 of these buggers! Going shopping with Thomas is fun! :T :E

Those of us of more modest means have to be content with getting excited over receiving 4 - RS100-4 today... sure are cute little buggars, but I think they're going to need aluminum plates to mount on for adequate rear window. Have to see how they test out this weekend.

[ThomasW]

Jon:
Can you explain this in further detail as far as determinig how wide the gap should be and pitfalls to look for in design or just a plain old rule of thumb?

Chuck

I ask him the same question last week.

Answer, 2-3" should be fine....

[Hank]

Okay, 25 of the Peerless ordered (with the help of The Kid).
Keep us posted on this "gap" thing. If it really applies to the RD's, as opposed to your true ribbons (I do understand true ribbon fragility), then okay. But if not, I'd sure like to do one solid baffle.

[Amphiprion]

25 HDS drivers - should be a heckuva project Hank! Looking forward to your design and helping out if you decide to go active.

[JonMarsh]

Okay, 25 of the Peerless ordered (with the help of The Kid).
Keep us posted on this "gap" thing. If it really applies to the RD's, as opposed to your true ribbons (I do understand true ribbon fragility), then okay. But if not, I'd sure like to do one solid baffle.

No issue with RD-s they have a relatively heavy film under tension. True ribbons, that's another matter.

[chasw98]

Okay, 25 of the Peerless ordered (with the help of The Kid).
Keep us posted on this "gap" thing. If it really applies to the RD's, as opposed to your true ribbons (I do understand true ribbon fragility), then okay. But if not, I'd sure like to do one solid baffle.

HanK:
Our small club is growing. I've got 24 on the way, you've got 25, and Thomas has a zillion on the way. We need to collaborate on the design so we/I don't do this twice. Are you thinking of RD75's or possibly Neo8 PDR's? Thomas has raised that question with me.

I still don't get the 'gap' thing but it sort of makes common sense in a way. In going over the AudioWorx and ALSR site, nobody used a gap at all. OTOH, they were all built at least more than 5 years ago when design technology was not as evolved(?) as it is today maybe. Almost all of the designs have fairly broad 'wings' for the RD75 and most of them do not use an array for the woofers. One idea I am thinking about is that I can cover the 'gap' with acoustically transparent grille cloth so the front will appear seamless in a room. Just covering the gap only, not the woofers or the RD75. I still have not come up with a way to build and safely support/brace the woofer/RD75 array that will also be esthetically pleasing. I have some ideas that may come to fruition involving aluminum, MDF, and Oak but I am still working out the details. The drivers arrive on Tuesday and I will probably sacrifice a sheet of MDF to test building and mounting 12 drivers in it for measuring and mounting possibilities this next weekend.

Chuck

[Johnloudb]

No issue with RD-s they have a relatively heavy film under tension. True ribbons, that's another matter.

What about diffraction issues. Is there any benefit to having a gap, between the woofers and RDs? I'm drawing up plans for my RD50 and 6 Usher 8" woofer configuration. I was considering having a completely separate baffle for the RD50 so I could position it how it sounds best. But I'm rethinking that - probably a waste of time? But, I'll may leave a gap in there.

[ThomasW]

If nothing else having a gap would decouple the planars from the reactive vibrations created by the dynamic drivers shaking their section of the baffle.

Linkwitz goes to great length to demonstrate the effects of this for his Orion project. I don't know if I can get motivated to build a magnet based mounting system for 2 dozen drivers.