• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

ASR Directiva Open Source Speaker Review

ROOSKIE

Major Contributor
Joined
Feb 27, 2020
Messages
1,915
Likes
3,394
Location
Minneapolis
Sure, maybe it's not, but it's got a flat response and THD below 5% from 40Hz upwards at 86dBSPL, in a small package. Can you point to other speaker measurements that cause you to say it's not special?
I feel the JBL A130 is one example. Very good above 55hrz, quite low in distortion (and subjectively I though sound excellent) and on sale a pair of complete speakers costs less than 1/2 of one bare purifi woofer. I'd say if you are going to use a sub/subs then the purifi is really hard to value. Though compression is not measured here.
The A130 can be Eq'd to a 6+ harman score with 8+ using a sub as well.

(not saying I am not impressed with this speaker - I am, just not as sure about the woofers due to price)
 
Last edited:

respice finem

Major Contributor
Joined
Feb 1, 2021
Messages
1,867
Likes
3,774
It would be very hard to surpass the studio monitor "establishment" I guess, but as a "case study" it is very interesting.
Prices can only be taken down with mass production, is there enough demand for a "newcomer"?
But then, maybe the Purifi esteem will help.
 

thewas

Master Contributor
Forum Donor
Joined
Jan 15, 2020
Messages
6,731
Likes
16,156
Now, we just need to bring the price point down below the magic $1000 a pair price point and this might just become the Objective2 of speakers starting a movement among audio companies to aim for absolute objective fidelity.

As expected from @ctrl and the chosen drivers (the Seas DXT tweeter is used also on Kii Three and Grimm LS1 and no words needed about the Purifi woofer) one of the best 2-way loudspeakers someone can buy or build, hope also this cheaper and passive but also very good measuring alternative will be NFSed one day https://heissmann-acoustics.de/en/dxt-mon-182/
 

LTig

Master Contributor
Forum Donor
Joined
Feb 27, 2019
Messages
5,760
Likes
9,442
Location
Europe
This is an outstandingly good result for a 2-way speaker, due to great design and very good but expensive drivers. I'm wondering though if a 3-way design using cheaper drivers might be better in the end for less money (see the KH310).
 

McFly

Addicted to Fun and Learning
Joined
Mar 12, 2019
Messages
903
Likes
1,861
Location
NZ
Interesting review. :)

I'm not sure what to make of it however. Has it been EQ'd in DSP within an inch of its life and if so, why the obvious hole in the response, at the crossover point, dead in the most important part of the midrange?
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:
1633336795734.png


Bravo to the directiva team.

Encore!! Passive design!!
 
Last edited:

aac

Active Member
Joined
May 17, 2020
Messages
217
Likes
163
This is an outstandingly good result for a 2-way speaker, due to great design and very good but expensive drivers. I'm wondering though if a 3-way design using cheaper drivers might be better in the end for less money (see the KH310).
From the thread I believe format was chosen because of the easier shipping.
For DIY I'd prefer to look at something like "classic" 3 way with 12 inch woofer. Maybe even closed box.
For the price of purify woofer a 6.5 midrange and 12 (15?) inch woofer looks possible.
 
Last edited:
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
44,368
Likes
234,381
Location
Seattle Area
Isn‘t this using a MiniDSP and utilizing its ability to do 10 bands of PEQ?
Yes. A handful of filters are in there in addition to crossover.
 

MZKM

Major Contributor
Forum Donor
Joined
Dec 1, 2018
Messages
4,240
Likes
11,462
Location
Land O’ Lakes, FL
Great effort but the value, apart from having fun building it, is not there. A pair of Genelecs 8040 will be cheaper and at least as good.
Bass & max SPL will probably go to the Directiva.

But if I was wanting to buy a computer speaker, I’d go 8040 (not a DIY guy).

Though, this project seemed mainly about showing what is possible using modern methods & access to the NFS scanner (though virtualized/estimated Spinoramas were used in VituoxCAD) with a semi-restrained budget (go crazy and build a tower with a 34mm BlieSMa tweeter, dual 4.5” Purifi as MTM midrange, dual 6.5” Purifi woofers, and dual side-opposing Purifi passive radiators; though some Satori Textreme woofers (similar to Perlisten) seems awesome too).
 
Last edited:

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,221
Likes
17,798
Location
Netherlands
This is quite an achievement. Thumbs up to everyone involved!

Since we don't have a lavish marketing page for this product with fluffy language to admire, it would be nice to have a short write-up on the features design principles and design incarnation to come to this version. It would save a lot of people a lot of reading work on the Directiva topic And don't skimp on the hyperbole ;)
 

abdo123

Master Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
7,423
Likes
7,940
Location
Brussels, Belgium
I expected @amirm to find the design a bit on the bright side due to the 'directivity error'.

Hopefully the next iteration of the speaker would smooth that out :).

Considering that the woofers only cost as much as an LS50 Meta, i think this design gets ALOT of things really well (in terms of output and response linearity) but future iterations should primirarily focus on ironing out that directivity error and then just smoothing out the LW with EQ if the tweeter had to be changed.

Would love to see future iteration with 2 or 4 Purifi woofers with a linear response all the way to 20Hz with front ports / front passive radiator.
 

ctrl

Major Contributor
Forum Donor
Joined
Jan 24, 2020
Messages
1,616
Likes
6,086
Location
.de, DE, DEU
Great effort but the value, apart from having fun building it, is not there. A pair of Genelecs 8040 will be cheaper and at least as good.
This looks amazing until I saw the price, now time to go back to genelec and Neumann with my bank account
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.


My hope from this review would be that the purefi woofer would somehow distinguish itself in terms of bass or output but this review doesn't seem to indicate anything special.

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.
1633328936799.png

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.
1633328058963.png




Curious about those large distortion spikes at 96dB THD.
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.
1633329664882.png


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:
1633330291639.png



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

Attachments

  • directiva_v20.zip
    1.4 MB · Views: 173

McFly

Addicted to Fun and Learning
Joined
Mar 12, 2019
Messages
903
Likes
1,861
Location
NZ
I thought this was the final filter design?
Didn't say final. I said filter design. Its open source, so waiting to see what it is at all? What we see is the summed response of two drivers with DSP, but what EQs and Xover slopes have been used to get here?

EDIT: NVM, @ctrl posted it above you! EPIC!!
 
Top Bottom