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Directiva driver candidate discussion

Rick Sykora

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Initially kept Directiva driver discussions within the design team, but they still get to make the final call. Since folks like to discuss their favorite drivers, giving it its own thread should keep the main thread tidier too.

Am finding out about new vendors constantly. Some very interesting ones do not make the cut because they lack distribution outside their region. As Directiva is open source, seems appropriate to have a more open forum to discuss. This will also provide a place to share internal team decisions regarding drivers.

So please propose your driver candidates in the thread below. While ok to post your favorite driver, for it to be used, it needs to be a candidate for a target speaker. For example, r1 uses the Purifi 6.5 woofer. If you are proposing another woofer for r1, it is a another release and gets assigned a release number (like r1.1).

Thanks!

Rick
 
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digitalfrost

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I think the Purifi driver should be replaced. It's too expensive and most people will use subwoofers anyway. So what you're paying for is actually not used.

Popular combinations for the DXT tweeter are Seas ER18RNX and the Wavecor WF152BD06 or WF182BD09. I would in general prefer a woofer that doesn't try to do bass. The ER18RNX will do 80hz at -3dB if put in a closed box...
 

hex168

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Since the DXT can do 87-88dB 1w/1m, the Peerless FSL 6" can do that with full baffle step compensation:
As Digitalfrost pointed out above, most will use subs anyway. Consider it the non-Purifi approach to low distortion - let the sub do the large excursions.

Along similar lines, slightly less sensitive but with demodulation rings:
It tested quite well:

Also, Faital Pro 6FE100:
 

alex-z

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I think keeping the Purifi drivers is the right move. They put in a fair amount of work to keep force factor modulation (FFM) and surface area modulation (SAM) to a minimum. Simply adding shorting/demodulation rings is a good addition for cutting down on inductance variation, but directly helps with neither FFM or SAM.

There are certainly some options like the Satori MW16TX and Morel 634Nd which have optimized cone and motor structures, but to my knowledge, the Purifi drivers are practically unique in their surround design. Both are cheaper than the Purifi 6.5" woofers, but only by $100 each.
 

hifi-alex

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I‘d still go with the SB15NBAC, superb midrange performance when supported by a subwoofer and way cheaper than most of the alternatives which could compete (if at all)
 
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Rick Sykora

Rick Sykora

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I think the Purifi driver should be replaced. It's too expensive and most people will use subwoofers anyway. So what you're paying for is actually not used.

Popular combinations for the DXT tweeter are Seas ER18RNX and the Wavecor WF152BD06 or WF182BD09. I would in general prefer a woofer that doesn't try to do bass. The ER18RNX will do 80hz at -3dB if put in a closed box...
I think keeping the Purifi drivers is the right move. They put in a fair amount of work to keep force factor modulation (FFM) and surface area modulation (SAM) to a minimum. Simply adding shorting/demodulation rings is a good addition for cutting down on inductance variation, but directly helps with neither FFM or SAM.

There are certainly some options like the Satori MW16TX and Morel 634Nd which have optimized cone and motor structures, but to my knowledge, the Purifi drivers are practically unique in their surround design. Both are cheaper than the Purifi 6.5" woofers, but only by $100 each.

Context is important here so please provide. Another less expensive woofer for r1 makes sense. Would prefer to think of it as a r1.5 as any major change to cone profile is going to affect the design significantly.

@digitalfrost you seem to suggest you want another speaker than r1. If so, a different driver makes sense. Replacing the Purifi in r1 is no longer a Directiva r1 in my view.

Everyone has different needs and tastes. I think subwoofers are useful but my wife does not care for them and sometimes space does not allow for them either. I suggest a tower speaker is a good compromise and still plan to do. I do struggle with the 6.5 inch Purifi purely for use solely as a woofer in this case and multiples make it too pricey vs alternatives. The r2 team has been looking at some Wavecor woofers that look promising and the larger Dayton Epique is viable too. Wavecor availability in US is a concern and so has slowed its evaluation.

@alex-z agree that a substitute r1 driver is pointless unless it is much less expensive than the Purifi. As mentioned above, really becomes an r1.x. :)
Since the DXT can do 87-88dB 1w/1m, the Peerless FSL 6" can do that with full baffle step compensation:
As Digitalfrost pointed out above, most will use subs anyway. Consider it the non-Purifi approach to low distortion - let the sub do the large excursions.

Along similar lines, slightly less sensitive but with demodulation rings:
It tested quite well:

Also, Faital Pro 6FE100:

In a something beyond r1, have looked at the Peerless and others have suggested too. Agree there is potential in the right application.

Have not looked at the GRS, but will. The Faital Pro gets axed as the octagonal frame seems more build hassle than any benefit it might provide. Convince me otherwise and maybe will reconsider.
 

hex168

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Would you consider surface mounting and a felt front panel cutout for the Faital? Easier than the woodworking hassle the octagonal frame otherwise requires. Aesthetics might be an issue but others are more creative in that respect than I am.

I haven't used them myself but they were selected by Bill Waslo for the SmallSyns (a very different application, for sure) and the smaller version tested well at:

I'm not sure what the added benefit of the Faital would be over the Peerless or GRS, but that is what testing is for. I lean towards the Peerless only because of experience with other Peerless woofers.
 
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Mashcky

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Any thoughts on tweeter? Is the SEAS DXT just too hard to pass up again or is there another drive being considered?

I would be fascinated to see an updated ER18RNX + DXT speaker, if only because I have the ER18DXT already and could rebuild mine into a better speaker
 
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Rick Sykora

Rick Sykora

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Any thoughts on tweeter? Is the SEAS DXT just too hard to pass up again or is there another drive being considered?

I would be fascinated to see an updated ER18RNX + DXT speaker, if only because I have the ER18DXT already and could rebuild mine into a better speaker
Always looking for a better driver, so no the DXT is not the only tweeter to be considered. In r2, we are busier with the woofer and midrange, so keeping the DXT was less work.
 
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Rick Sykora

Rick Sykora

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DanielT

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Also, Faital Pro 6FE100:
But it has high distortion from what I can see. A bit blurry pictures, maybe someone else can see them more clearly?

I found the test on the Faital Pro 6FE100 here:

Screenshot_2022-10-26_172605.jpg


adamhall.s3.amazonaws.com
https://adamhall.s3.amazonaws.com › ...PDF
Table 1: Faital 6FE100 Woofer. - AWS
(Damn I can't copy the link, google it, see attached picture and you will find it)


I‘d still go with the SB15NBAC, superb midrange performance when supported by a subwoofer and way cheaper than most of the alternatives which could compete (if at all)
It is very popular these days. :) I have it myself and intended to use it as a midrange driver in a pair of three-way DIY speakers. The only thing I'm thinking about is those nasty breakup frequencies. If it becomes audible or not, even if you use a 24dB filter and set the crossover somewhere between 1900-2500 Hz?

sb15nbac30-4_offaxis_0 (2).png



At least MAB thinks so with another driver that has unpleasant breakup modes, here's a thread about it and how he solves it:

Screenshot_2022-10-26_173319.jpg



A number of these in a line speaker?:)

 

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Marc v E

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Context is important here so please provide. Another less expensive woofer for r1 makes sense. Would prefer to think of it as a r1.5 as any major change to cone profile is going to affect the design significantly.

@digitalfrost you seem to suggest you want another speaker than r1. If so, a different driver makes sense. Replacing the Purifi in r1 is no longer a Directiva r1 in my view.

Everyone has different needs and tastes. I think subwoofers are useful but my wife does not care for them and sometimes space does not allow for them either. I suggest a tower speaker is a good compromise and still plan to do. I do struggle with the 6.5 inch Purifi purely for use solely as a woofer in this case and multiples make it too pricey vs alternatives. The r2 team has been looking at some Wavecor woofers that look promising and the larger Dayton Epique is viable too. Wavecor availability in US is a concern and so has slowed its evaluation.

@alex-z agree that a substitute r1 driver is pointless unless it is much less expensive than the Purifi. As mentioned above, really becomes an r1.x. :)


In a something beyond r1, have looked at the Peerless and others have suggested too. Agree there is potential in the right application.

Have not looked at the GRS, but will. The Faital Pro gets axed as the octagonal frame seems more build hassle than any benefit it might provide. Convince me otherwise and maybe will reconsider.
How about a wife friendly subwoofer design for the next directiva build then?
 
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Rick Sykora

Rick Sykora

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How about a wife friendly subwoofer design for the next directiva build then?

Lol, in my wife's case, that means no subwoofer!
 

DanielT

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How about a wife friendly subwoofer design for the next directiva build then?
A subwoofer under the sofa perhaps? If it fits under the sofa, that is.High WAF.:)

Here is an example of one with two Dayton Audio LS10-44:

subb under soffan (1).jpg

I am attaching some miscellaneous pictures of it. Not my sofa subwoofer, I should add.
 

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Marc v E

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A subwoofer under the sofa perhaps? If it fits under the sofa, that is.High WAF.:)

Here is an example of one with two Dayton Audio LS10-44:

View attachment 239584

I am attaching some miscellaneous pictures of it. Not my sofa subwoofer, I should add.
This is a great idea. I was thinking myself of hiding a subwoofer by making it part of a tv cabinet. Maybe I should leave it at this point before I derail the thread :p


Btw my 2 cents about the choice of drivers is that they should be cheap. As the D&D 8c and other wel regarded speakers seem to use relatively cheap drivers, why shouldn't we?
 

ryanosaur

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This is a great idea. I was thinking myself of hiding a subwoofer by making it part of a tv cabinet. Maybe I should leave it at this point before I derail the thread :p


Btw my 2 cents about the choice of drivers is that they should be cheap. As the D&D c8 and other wel regarded speakers seem to use relatively cheap drivers, why shouldn't we?
(FWIW, I've seen guys do Devastators that look like Side Cabinets... totally doable! :) )
 
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Rick Sykora

Rick Sykora

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So...
Quad 24s then? :D

You can compromise and settle on 21s from Harbottle! ;)

When my wife sees my big towers she may compromise. She keeps reminding me that my hobbies need to fit in one room in our next place.

Am starting to think that one room looks like this…

1666803271068.jpeg
 
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