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Directiva r2 project: market requirements gathering

voodooless

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While the D&D approach would seemingly be lower cost, if we have to iterate multiple prototypes to get the tuning right, am less inclined to take on the likely added cost of time/materials to do so.
It will cost additional time for sure, but material cost can be limited greatly with some clever engineering upfront. One does not need to build many enclosure incarnations. One flexible enclosure can be used to test them all.

Looking forward to the requirements list! Probably good to also write down a list of open questions that need to be answered to complete the list. That would help steer discussion.
 
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Rick Sykora

Rick Sykora

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It will cost additional time for sure, but material cost can be limited greatly with some clever engineering upfront. One does not need to build many enclosure incarnations. One flexible enclosure can be used to test them all.

Looking forward to the requirements list! Probably good to also write down a list of open questions that need to be answered to complete the list. That would help steer discussion.

Yes, just may be a tradeoff between design time and implementation cost too.

Since it it not my area of expertise, will depend on who else might do (@TimVG perhaps)?
 

voodooless

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One might also consider putting in some extra time in some simulation tools in this regard. I have no idea if possibly something like Akabak might be helpful in simulation leaky enclosures with dense fillings? Are there any people here familiar with with using it? It’s free for non-commercial use.
 

TimVG

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Yes, just may be a tradeoff between design time and implementation cost too.

Since it it not my area of expertise, will depend on who else might do (@TimVG perhaps)?


Would be happy to from January onward if that suits the timetable. I agree on the modular enclosure for testing purposes.

FYI the lead designer of the D&D 8C who eventually left the company (although they're still friends) already did a similar DIY project involving a passive cardioid system for the midrange (as in the 8C) but with a seperate bass unit with 3 forward and 2 rear drivers (active cardioid), and 4 channels of amplification per channel. The side vents are covered by cloth, but they're there. The front baffle of the top is solid, custom machined aluminium featuring a waveguide of his own design. It's full range constant directivity.

1634928052992.png
 
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abdo123

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Would be happy to from January onward if that suits the timetable. I agree on the modular enclosure for testing purposes.

FYI the lead designer of the D&D 8C who eventually left the company (although they're still friends) already did a similar DIY project involving a passive cardioid system for the midrange (as in the 8C) but with a seperate bass unit with 3 forward and 2 rear drivers (active cardioid), and 4 channels of amplification per channel. The side vents are covered by cloth, but they're there. The front baffle of the top is solid, custom machined aluminium featuring a waveguide of his own design. It's full range constant directivity.

View attachment 160764

takemymoney.jpg


Please tell me where are the plans for this!
 

dc655321

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Would be happy to from January onward if that suits the timetable. I agree on the modular enclosure for testing purposes.

FYI the lead designer of the D&D 8C who eventually left the company (although they're still friends) already did a similar DIY project involving a passive cardioid system for the midrange (as in the 8C) but with a seperate bass unit with 3 forward and 2 rear drivers (active cardioid), and 4 channels of amplification per channel. The side vents are covered by cloth, but they're there. The front baffle of the top is solid, custom machined aluminium featuring a waveguide of his own design. It's full range constant directivity.

View attachment 160764

Cardioid AND cat-approved?!?
What magic is this?
 

TimVG

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What I'm implying is, one could start off with a similar top (2-way, active or passive) and design different bass modules to fit different needs. A semi-modular system if you will.

A Seos 10 combined with a capable tweeter for instance (he used very common Seas H1212-06 27TBFC/G) would be a good start.
 

TimW

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Would be happy to from January onward if that suits the timetable. I agree on the modular enclosure for testing purposes.

FYI the lead designer of the D&D 8C who eventually left the company (although they're still friends) already did a similar DIY project involving a passive cardioid system for the midrange (as in the 8C) but with a seperate bass unit with 3 forward and 2 rear drivers (active cardioid), and 4 channels of amplification per channel. The side vents are covered by cloth, but they're there. The front baffle of the top is solid, custom machined aluminium featuring a waveguide of his own design. It's full range constant directivity.

View attachment 160764
Dang I wonder what the BOM was for this project.

The top and bottom, although separate, probably have to be made to match each other for directivity purposes right?
 

voodooless

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What I'm implying is, one could start off with a similar top (2-way, active or passive) and design different bass modules to fit different needs. A semi-modular system if you will.
I think that is a great idea! Directiva R2.1, R2.2 or R2.3, from lower budget version, to high end cardioid.

Man, 5x8” (per side) isn’t going to be cheap! It surely looks impressive!
 

TimVG

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Dang I wonder what the BOM was for this project.

The top and bottom, although separate, probably have to be made to match each other for directivity purposes right?

High BOM :)

I think he actually tuned the bass module to give the best in-room response, although you could adjust the directivity as you wish (if you have the right data to work off of).
 

voodooless

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A Seos 10 combined with a capable tweeter for instance (he used very common Seas H1212-06 27TBFC/G) would be a good start.
Isn’t a Seos waveguide kind of unobtainium? Even more so outside of the US. Even a 3D printed custom design might be more approachable since local 3D shops are kind of ubiquitous nowadays.
 

TimVG

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Isn’t a Seos waveguide kind of unobtainium? Even more so outside of the US. Even a 3D printed custom design might be more approachable since local 3D shops are kind of ubiquitous nowadays.

I'm sure there's solutions. They're out of stock with DIYSG - but has anyone contacted Denovo and simply asked what quantity they'd need to order for them to produce a batch?
 

tuga

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What is the operating frequency of the 8c slots?

D&D sold a non-cardioid version called the 8m. The directivity is somewhat different above 500Hz and not shown below that...

D&D 8m
6rRRJR0.png


D&D 8c
2l2dt38.png
 

TimVG

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What is the operating frequency of the 8c slots?

D&D sold a non-cardioid version called the 8m. The directivity is somewhat different above 500Hz and not shown below that...

D&D 8m
6rRRJR0.png


D&D 8c
2l2dt38.png


They also made a cardioid PA speaker and subwoofer as seen here
 

voodooless

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What is the operating frequency of the 8c slots?
Should be from 100 to a slow roll off after 500 Hz. That’s about the baffle step, so below you need the slots to work the hardest, above just to match up with the tweeter.
 

abdo123

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I think that is a great idea! Directiva R2.1, R2.2 or R2.3, from lower budget version, to high end cardioid.

Man, 5x8” (per side) isn’t going to be cheap! It surely looks impressive!
I also agree, and i think this is only strategy i have to get this thing in close proximity to my partner.

We have to divide it up into stages! :D
 

617

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At the risk of looking like an idiot, is there any reason in a domestic setting to use cardioid radiation below 200hz or so?

Any in room measurements to make the case for directivity at lf?
 

TimVG

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At the risk of looking like an idiot, is there any reason in a domestic setting to use cardioid radiation below 200hz or so?

Any in room measurements to make the case for directivity at lf?

There was some discussion about that - I believe the consensus from both D&D designers was once you reach the modal region of the room it becomes more or less pointless. From an engineering perspective however it's just cool to achieve.

And as we've seen in this forum, different people want different things - and a semi-modular design would allow for that. It's not even all that difficult to achieve. The main challenge will be the top cabinet :)
 

tuga

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They also made a cardioid PA speaker and subwoofer as seen here

I like the look of "floating" mains on stilts with short bass modules as footings, a bit like the Grimm LS1.
 

sigbergaudio

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Hey, that was our concept! :)

We're already making a modular system with subwoofers, and we're on the drawing board for our next loudspeaker, and that may end up being designed so that our 10D subwoofer can act as stands.

And oh, what are those things on the sides? Seems like many similar ideas are floating around these days. :)


4F783E98-6E52-4377-8AA5-6A148C017BDE.jpeg
 
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