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ASR Directiva Open Source Speaker Review

restorer-john

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@ctrl so this speaker has a passive internal 2 way crossover and it's cleaned up additionally with DSP?

What is it like without DSP? Excellent and just needs a bit of help?
 

ctrl

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@ctrl so this speaker has a passive internal 2 way crossover and it's cleaned up additionally with DSP?
What is it like without DSP? Excellent and just needs a bit of help?
No, it's a pure active design.
But as far as I know, @Rick Sykora is also planning a passive version. But Rick should answer that himself.
 

TLEDDY

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Please forgive my ignorance... what amplifier is being used for the test? I have read the thread and I simply am missing that piece.
 

restorer-john

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No, it's a pure active design.
But as far as I know, @Rick Sykora is also planning a passive version. But Rick should answer that himself.

Ah, I misread Amir's statement as saying there was PEQ in the MiniDSP additional to the crossover. The crossover is also in the Mini DSP. :)
Yes. A handful of filters are in there in addition to crossover.
 

Solveit

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Please forgive my ignorance... what amplifier is being used for the test? I have read the thread and I simply am missing that piece.
"This is an active design so I build a compact system to drive it comprising of the Minidsp 2x4 HD and SMSL VMV A2 desktop amplifier. "
 

ctrl

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Is this something a regular person with a MiniDSP can help with?
For this purpose, @Rick Sykora has already tried and measured a lot.
If I remember correctly, the frequency deviations between VCAD and NFS measurement are not due to differences in VCAD versus miniDSP filters.
I can't provide more detail because I use FusionAmp plate amplifiers for my active speaker projects.

Ah, I misread Amir's statement as saying there was PEQ in the MiniDSP additional to the crossover. The crossover is also in the Mini DSP.
Yep, that's exactly how it is.
High-pass filter at 30Hz is optional - for woofer protection at high sound pressure level.

And who likes can set many more PEQ and so increase the rating-score ;)
1633340402169.png
 

GXAlan

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Great work. How exciting to see progress in this field. I think at 4-5k, it does show how good the “big guys” are at industrializing and mass producing premium products, but for the hobbyist, at $1500, it’s a nice option.

One “challenge” of homebrew speakers is that while you can buy speakers with pretty nicely designed grilles that are designed to minimize diffraction. For homebrew speakers, grilles are usually an afterthought. That would be something to look into as well.
 

Rick Sykora

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Hi folks!

Thanks for all the kind comments on this key milestone for the Directiva r1 speaker!

Before I add some of my own comments about this particular review, I would like to thank @amirm for his support and @ctrl for his outstanding contributions (and perseverance). I will get around to responding to all of the directed questions/comments in later posts, but also want to acknowledge 2 other early design consultants. One being Rick Craig who collaborated on the passive radiator and tweeter selection. Another was @DDF who helped with the tweeter selection and evaluating box alignments.

So as Amir indicated, Directiva started as his idea and really had only a few requirements:

1. The speaker should be an active design
2. The speaker should attain a high Olive score (a lot more goals buried in here ofc)
3. The speaker should (preferably) use the Purifi 6.5 woofer

At a high level, I added a couple more goals. Make it easy to build/attain and a target price around $1000. Pleased to say, most of these goals were accomplished with the exception being the cost is a bit higher. As mentioned, the woofer is a bit pricey, so allowed that constraint to flex a bit. More details are in the Directiva thread, so for the sake of brevity, will not repeat here.

Amir asked that I comment on the tweeter. As the main Directiva thread details the alternatives, the short answer is that the Seas DXT tweeter offered the best performance/performance within the overall budget constraints. It is also a proven performer that the @ctrl and other experienced designers approved.

A quick note on a key implied requirement (of my own). The speaker would be targeted to be able to be used for music listening at 3-4 meters in a medium size room (~50 cubic meters) and produce solid bass down to 40 Hz (even away from walls). So, this speaker is designed to be used a far-field monitor. This pushes the Purifi woofer a bit, but one is up to the task and two should be quite satisfying (without a subwoofer). This was my main contribution to the design, most of the rest is @ctrl's fine work.

Since most of the review speaks for itself, I have only 2 notes beyond what @ctrl has already posted. While I have improved my speaker measurement rig considerably, it is not a Klippel and am limited to how low I can reasonably measure. However, am confident that the major resonances in Amir's distortion (and likely CSD) plots are not due to the speaker, but due to the amp/mindisp resting on top of the speaker. The only major distortion I encounter is around 400-500 Hz and it is primarily even order.

Second, I am not very tolerant of hiss from my equipment. I am using a Hypex MC252MP amp in my test setup and so perhaps is quieter than the SMSL amp that Amir used. To further reduce hiss in the future (and better protect the tweeter), I plan to use a hybrid active/passive crossover for the upper frequencies.

Finally, would like to again express my gratitude to @ctrl for his collaboration on this project. He deserves the credit for all that was done well in Directiva and any shortcomings are (likely) my fault!

Cheers,

Rick
 
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voodooless

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Thanks for the write-up, Rick!

3. The speaker should (preferably) use the Purifi 6.5 woofer

At a high level, I added a couple more goals. Make it easy to build/attain and a target price around $1000. Pleased to say, most of these goals were accomplished with the exception being the cost is a bit higher. As mentioned, the woofer is a bit pricey, so allowed that constraint to flex a bit. More details are in the Directiva thread, so for the sake of brevity, will not repeat here.
So your starting point was already chosen so that the budget goal was already hard to reach? Luckily the excellent tweeter is budget-friendly :) Also, this budget does not include the active parts, does it? Amir's amplifier already costs $999, and you need two of them. Obviously cheaper options are available :)

One could probably shoehorn a Hypex MC and miniDSP in a small base to make a compact full contained unit. Or you could build it into a stand.. lots of options really.
 

Rick Sykora

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Not sure the design and tooling for that Purify driver could in any way be described as "minimal resources"

...and the use of Amir's Klippel AND @ctrl's smarts! The only part that might be considered minimal was the size of the team. ;)
 

Rick Sykora

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Hole in the response?

Hole in the response??

Just kidding, but the “slight dip” in the response is virtually unavoidable due to the 2 way design, the distance between the drivers and the crossover creating a cancellation on the vertical off- axis and thus a mild cancellation in the perceived in room total response.

I doubt there are many, if any, two ways which aren’t coaxial designs that don’t have this dip *without bumped on axis response in the same reigon*

Edit: I wouldn't call this ËQd to within an inch of its life:
View attachment 157115

Bravo to the directiva team.

Encore!! Passive design!!

Since you posted the crossover design here, will also share that due to flatter response, the woofer in my speaker does not need that 1960 Hz peak filter. It is newer than the one in Amir's speaker, so hopefully can be removed for the published design. So, neither driver has a lot of filters, but the woofer is likely down to 3. :cool:
 

Rick Sykora

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Fantastic work!!!!!

It is almost like a parts express box + some nice drivers + some effort = a very nice speaker for less than others are charging with probably better parts.

Will you make a thread for alternate XO's or want posts the in the DIY thread?

Will make a thread for alternative crossover in the DIY section. :cool:
 

Rick Sykora

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Well @Rick Sykora said they're interested in making a bigger directiva, so i thought that implied more drivers. and you need them in pairs if you want to maintain decent vertical directivity.

Am not limiting the next Directiva to only using Purifi woofers, but we will see. The first one was for Amir, this one is for me! ;)
 

Absolute

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For this purpose, @Rick Sykora has already tried and measured a lot.
If I remember correctly, the frequency deviations between VCAD and NFS measurement are not due to differences in VCAD versus miniDSP filters.
I can't provide more detail because I use FusionAmp plate amplifiers for my active speaker projects.
Minidsp uses proportional Q filters while Hypex and most other uses Constant Q filters. Could this explain it?
 

Rick Sykora

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No, it's a pure active design.
But as far as I know, @Rick Sykora is also planning a passive version. But Rick should answer that himself.

Several folks have asked for a passive version, so plan to do. Both of us have started on it, so hope to post something soon.
 

voodooless

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Am not limiting the next Directiva to only using Purifi woofers, but we will see. The first one was for Amir, this one is for me! ;)
I think this would be an excellent idea. While an excellent woofer, the price is quite exorbitant for a 6.5" monstrosity.
 
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