ASR Directiva Open Source Speaker Review

[ROOSKIE]

I’d like to see what can be done to a low price point - maybe $300 in materials for a $1000-1200 commercial design. That would be much more complicated, and it’s not my time being spent

Super happy to see the Purifi treated well here and the speaker seems well engineered and yes still expensive.
So going off your lead.

To save money without losing a lot of performance.

The same tweeter here could be used with other known excellent woofers and come in under $500.

For a real budget, you could deff get near $300 if one went with Dayton RS woofers though they are not nearly as unique. My RS180 woofers are a superb value @ $120 or less for a pair.(2)

SB acoustics has their myriad options for around $100-125 each.

Misco has 2 newish woofer out with nearly the excursion of the Purifi and they are
$135each

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One superb option could be the Wavecore WF182BD (or CSS LDW7) at $150-160 each.

The old standby Anarchy woofers could be an option for much less than the Purifi.

All of these designs can use a port that fits the box, or there are passive radiator options. The issue with the Purifi is it basically requires a radiator due to port length. The other drivers will not, though that radiator might still be part of a sweet design.

As you can even see here confirmed via @voodooless, the radiator chosen is likely stressed at really high volume and the system even needs a larger one to truly be optimal. It seems the Purifi is just a tough driver to work with in a small box.

PS, for the right person. If one could get ahold of the woofers in the JBL l82 that would be sick, though not a good idea for a wide release. Likely they are hard to get and only from a few sources. They are incredible 8's in my humble opinion and the distortion I have measured of the speaker is low.

Anyway it great to the Purifi can work well, I am also excited to see if a less expensive woofer in a ASR speaker is on the table.

This could be a good alternative to the Seas tweeter. Goes down to 1.5khz with zero problems(Even lower with an 8th order) and will most likely fill the vertical directivity hole.

https://www.parts-express.com/pedocs/specs/264-1678--peerless-da32tx00-08-spec-sheet.pdf

I have that tweeter here, the only issue is no waveguide. I think here @ ASR that is not going to fly.
I am planning to partner mine with a few different woofers and see what I can get. That tweet is beast.

 

[abdo123]

So @abo123, this is not a no-compromise system. Nothing ever is.

The design would be less compromised if these valuable contributions showed up earlier

 

[aac]

Sorry as it may seem I am singling you out, but too often I see this same mistake being made on the forum overall...

While I appreciate what Genelec and others have accomplished, I think it is important to compare speakers that are intended for the same application space. A Genelec 8040 might be a well-designed nearfield monitor, but Directiva r1 was designed for use in far-field applications. Far-field (hifi) design puts a much greater demand on the speaker to be able supply more and lower bass (without a subwoofer) than the 8040 is able to deliver.

This would be no different than comparing the Genelec 8040 to a JBL Pro speaker. Nobody should expect a nearfield studio monitor to do duty as a high sensitivity sound reinforcement speaker (or vice versa). They are both speakers, but they are made for different applications. There is not much point in discussing value as the speakers are meant for different purposes.

Usually speakers meant for "far field" (whatever this means) have fairly large baffles and woofers to control their directivity lower. I don't think I've seen it the other way (with multiple small woofers and narrow baffle, maybe if some sophisticated design like active cardiod is used).

 

[thorvat]

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.


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
View attachment 157119

Seeems like a lot of headroom was sacrificied here. I have to admit I wasn't expecting a filter with such large amplitude at this particular frequency. Is it here to boost the entire LF range?

 

[abdo123]

Seeems like a lot of headroom was sacrificied here. I have to admit I wasn't expecting a filter with such large amplitude at this particular frequency. Is it here to boost the entire LF range?

Yes below 300Hz or so the sensitivity drops from 90 dB to 83 dB if i recall correctly.

 

[eboleyn]

The front looks almost exactly the same as some DIY speakers I bought the parts for back in December 2020, so I guess before this project kicked off. I didn't track this project starting so didn't know about it til today.

I also clearly used the same knock-down cabinet from Parts Express and similar if not identical Purifi mid/woofer driver, and mounted the driver the same way using the mid-height support posts for the outside screws, though I used a purely sealed design and a Raal 70-20XR tweeter. There is no crossover in my box at all and I expose all the taps on the back as binding posts (the tweeter has 3 positive taps with different impedances, so 4 just for that). I use a DEQX HDP-5 for active crossover.

They sound amazing, so clearly great minds think (partly?) alike. While the bass response is acceptable, to get strong sub-bass, I cross over with a Rythmik sub at 80 Hz (via the DEQX unit), and then the entire spectrum sounds clean and extremely accurate.

Pics:

 

[Tangband]

Yep, the Purifi driver makes the speaker an expensive DIY project.
However, the performance in terms of harmonic distortion (HD), intermodulation distortion (IMD) and displacement volume (DV, i.e. possible achievable sound pressure level in the low bass range) of the Purifi driver are exceptionally good.

With another woofer from SBAcoustics, for example, one could achieve a similar result at a much lower price, with a few sacrifices in HD, IMD and DV.




When you look at the measurements like this, it's almost boring.

On the other hand, we have a tiny speaker that, according to Amir's measurement, achieves an f3 of around 40Hz ( without DSP expansion) and can also produce reasonably low bass sound pressure levels due to the Xmax of +-10mm.
View attachment 157094

A cheap 6 or 6.5'' driver has a typical Xmax of about +-5mm. The displacement volume of the Purifi driver therefore corresponds to that of about two inexpensive 6.5'' drivers.

The quality of the drivers used is also reflected in the DSP settings. Very few corrections have to be made to achieve a good result.
View attachment 157087





As Amir said, the increased harmonic distortion around 400Hz was caused by the measurement setup.
In this frequency range, the Purifi driver and the passive resonator show no abnormalities.

The slightly increased HD3 (see 1. in the graph) around 9kHz and HD2 (see 2.) around 13.5kHz is due to the violent (damned translation programs ) breakup of the tweeter around 27kHz.
View attachment 157096

In Amir's measurement the 27kHz break-up is just visible due to the lowpass filter of the measurement system. In reality, this is much more pronounced and the cause of the (inaudible) increased HD values.
Manufacturer measurement of the Seas-DXT tweeter with break-up resonance at 27kHz:
View attachment 157098


For those interested, I have attached the complete VCAD project that corresponds to the version of Directiva measured by Amir.

Yes , the violent 27 KHz resonance in the tweeter is a real issue - especially if you play high resolution material . With 44,1 or 48 KHz sampling material theres no problem.

 

[Tangband]

One should remember that everyone can get a result like this with a good measurement program and a good mic.
…and a good midbass unit and tweeter.
You can also get a minidsp, two Aiyima a07 and make an already passive loudspeaker active by simply taking away the passive crossover.

It takes a while to learn how to make active loudspeakers, but very soon you’re gonna be able to construct a better speakers than an average passive loudspeaker.

The SB 26 ADC tweeter is a very good alternativ.

 

[voodooless]

The design would be less compromised if these valuable contributions showed up earlier

Not really, it might just be a different one.

 

[Koeitje]

Yes , the violent 27 KHz resonance in the tweeter is a real issue - especially if you play high resolution material . With 44,1 or 48 KHz sampling material theres no problem.

Can't you just roll of the response like crazy after 20kHz, you are not going to hear that anyway.

 

[thorvat]

Yes below 300Hz or so the sensitivity drops from 90 dB to 83 dB if i recall correctly.

To 83dB? Well, that is quite low..

 

[thorvat]

Can't you just roll of the response like crazy after 20kHz, you are not going to hear that anyway.

Exactly. The same way they did it with Butterworth 24 at 30Hz to save LF driver from trying to do what it cannot do.

 

[abdo123]

To 83dB? Well, that is quite low..

Flat Frequency response, High Sensitivity, and Small Size. pick two .

 

[Rick Sykora]

What would you change for a near-field setup?

How near and how close to room boundaries?

 

[digitalfrost]

How near and how close to room boundaries?

1m listening distance, 1 side wall ~ 1,5m away.

 

[thorvat]

Flat Frequency response, High Sensitivity, and Small Size. pick two .

Or add a 3rd driver to handle 20-300Hz?

 

[Bugal1998]

Great work by the team. I'm definitely intrigued and would like to hear them someday. Would be even more interested in seeing them put up against the Revels/Kefs/Nuemann/Genelecs of similar size in a double blind listening test.

Can you really design by measurements alone?

 

[617]

This could be a good alternative to the Seas tweeter. Goes down to 1.5khz with zero problems(Even lower with an 8th order) and will most likely fill the vertical directivity hole.

https://www.parts-express.com/pedocs/specs/264-1678--peerless-da32tx00-08-spec-sheet.pdf

Another, but very expensive..

BlieSMa T34A-4 | HiFiCompass

hificompass.com

I don't think the DI would be as smooth with the Bliesma or Peerless, but it might be acceptable. That DA32 is a serious tweeter for the money.

 

[Spkrdctr]

The flip side to this is what can we go out and buy that is as good or better for $1000 a pair? Anything? Anyone know of anything?

 

[voodooless]

The flip side to this is what can we go out and buy that is as good or better for $1000 a pair? Anything?

Exchange Purify for Satori WM16P. That should probably do it.