ASR Directiva Open Source Speaker Review

[musicforcities]

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

I suspect economy of scale comes into play. economy of scale comes into play at such prices. Hard to imagine trying to compete with Amir approved speakers around that range for example. But maybe not.

come to think of it…funky/creative designs, like using a compression driver with massive wave guide (a la JBL studio 530) may be one way to get more out of less expensive drivers. Or open baffle designs that drive down cabinet expense. Or KEF Ref / Vandersteen style of mid bass and bass in separate compartments with a dipole amt. if you could figure an economical way to handle the cabinetry (such as modifying a parts express box or two to stack). Or 3D print a giant honking wave guide.

Indeed if anyone has access to a cnc router one could do amazing things with a corian baffle with built in wave guides. So long as you don’t factor in time and tooling/equipment costs.

 

[musicforcities]

How about a sensitivity focused design for Home Cinema folks and for the future of the planet?

Use a renewable electricity provider. Managing carbon footprints with speaker sensitivity is not useful. We are not talking PA systems here.

The energy used to make any speaker, it’s materials, and ship it etc matters far more. Indeed, using one inefficient speaker for decades is likely better than any energy savings from sensitivity. Or indeed if the factory it was made in used coal based electricity. The amp efficiency matters more. The amount of time the amp is left on matters more. Or that it uses in standby mode.

With class D ones wireless router likely has a far larger energy footprint in use. And those are typically left on 24/7…

Though the lifespan and ability to repair class d is a huge factor when considering lifecycle energy footprints.

To save the planet in terms of audio, Get the best stuff you can and keep it forever. May even be cheaper amortized over the years. Repair it when it breaks.

 

[617]

I suspect economy of scale comes into play. economy of scale comes into play at such prices. Hard to imagine trying to compete with Amir approved speakers around that range for example. But maybe not.

come to think of it…funky/creative designs, like using a compression driver with massive wave guide (a la JBL studio 530) may be one way to get more out of less expensive drivers. Or open baffle designs that drive down cabinet expense. Or KEF Ref / Vandersteen style of mid bass and bass in separate compartments with a dipole amt. if you could figure an economical way to handle the cabinetry (such as modifying a parts express box or two to stack). Or 3D print a giant honking wave guide.

Indeed if anyone has access to a cnc router one could do amazing things with a corian baffle with built in wave guides. So long as you don’t factor in time and tooling/equipment costs.

The economic case for DIY is strong the larger the speaker gets. Building a huge subwoofer isn't any harder than making a small one, but big subwoofers cost far more than small ones.

Same with speakers. Making a speaker small presents a lot of challenges. This is a state of the art small speaker, but it would be outperformed if you replaced the purefi with a 10 inch woofer and a 4 inch midrange in a big box.

Well, in theory anyway. They did do a great job with this project.

 

[musicforcities]

They did do a great job with this project.

Agreed. It’s awesome. To me
The project is about the level of quality one can achieve today diy. I would be curious how crucial this particular woofer is though. Though again, the smaller one goes the more cost entailed for the woofer driver.

For example of what it takes fir a small speaker; I have a pair of mirage mrm 1 (which I was given…). Tiny stand mounts. 5inch woofers. But the drivers are built like a 1960s Volvo with massive voice coils and massive excursions. The tweeter has a massive magnet, vented pole, plays down to 2k or something nuts. The crossover is complex. The Cabinet has a 1.5”corian front baffle, and 1/4 steel lining sandwiched between mdf. They are over 30lbs each I think. They sound ten times larger than they are even in a 16x24 ft room. But simple they are not and I bet they measure worse than the Diectivas!

(The MRM - 1 imaging is very picky re room placement and the top end extends but is diffuse/soft and there is a dip in the presence region…aka “British hi fi tuning”. Nothing a bit of eq/dsp can’t fix but the imaging is always a pain. It’s super wide but getting it precise is a pita.) the low crossover point seems to be begging for a large AMT rather than a 1” dome. But these are from the early 1990s when such things were exotic.

 

[hex168]

Seems a stretch, but like the premise. Already using Class D amps partly to be more eco-friendly. As cannot do much about the speaker parts, seem the bigger opp is to get AVR designer to use Class D amplification. The problem is AVR packaging as ones with more desirable features usually have higher power amps...

Maybe yet another project to replace the crossover in a DIYSOUNDGROUP HT speaker?

What about substituting a Peerless FSL-0615R02-08 for the Purifi? I don't think a passive version could get the DXT loud enough, but active should be fine. It would need a sub or two, but efficiency is in another ballpark:

Home

Peerless by Tymphany FSL-0615R02-08 Professional 6-1/2" Midrange Woofer 8 OhmThis rugged woofer, with a high strength steel frame, 1.5" high temperature voice coil, and optimized suspension, is a terrific midbass for use in a compact PA speaker or even a midrange in a larger 3-way. The...

www.parts-express.com

A couple of AIYIMA A07s should do for amps.

Or, a FaitalPRO 6FE100. Not quite as loud as the Peerless, but with a demodulating ring and not as embarassingly cheap. Should work with the DXT active or passive:

Home

FaitalPRO 6FE100 6" Professional Midrange Midbass Woofer 8 OhmFaitalPRO's 6FE100 6" professional midbass woofer driver has an extremely flat response from 63 to 5,000 Hz for use in applications where high fidelity is required, such as studio monitors and reference speakers. Great off-axis...

www.parts-express.com

When I have time (who knows when that will be) I'd like to try the Peerless FSL with either a Peerless BC25TG15 or a DA25BG08 mounted on a board behind the front panel, with a ~6.5" hole in the front panel. Fill in from a circle on the tweeter faceplate to the front panel hole edge with self-hardening modeling clay, and you have a (rather unsophisticated) waveguide. My hypothesis is that a very shallow, e.g. 3/4" deep, waveguide can pull off being less sophisticated; I'll find out someday. It even looks like one could use the existing contour of the BC tweeter's faceplate as the throat of the waveguide and that's the hard part. Either of these tweeters would be louder than a DXT.

 

[richard12511]

Interesting review.

why the obvious hole in the response, at the crossover point, dead in the most important part of the midrange?

Hole? Dead?

We must be looking at different measurements. This is probably one of the 3 best 2 way speakers we've ever seen. There is a very slight directivity increase, but it's fantastically tiny. 90%+ of speakers have a much worse dip.

Can someone put the bass performance in some kind of reference for me? Better than a Revel f206? Better than a 708p? If it beats either of those, that is a huge win for a speaker of this size.

Comparing side by side with the 708p, this speaker digs about 7Hz deeper. 708p is down 1.9dB at ~47Hz; Directiva is down 1.9 at ~40Hz. Comparing the distortion side by side at 96dB:

Directiva has much better 96dB distortion performance where it actually matters. 708p has lower bass distortion where we can't really hear it. I'm assuming those 2 spikes seen on the Directiva graph aren't real(in the sense that they exist in the real listening situation). 708p might look better at 106dB(guessing), but 96dB is already loud enough for most, especially for a speaker this small.

Looking at the spins:

Directivity is about equal, but the Directiva is clearly better in terms of frequency response.

The Directiva is ~$1350 to build, while the 708p is ~$3,800(on Sweetwater with big sale, normally $4,600). I own the 708p, and I think it's amazing for the price, but this speaker looks even better(at least at 96dB). Seeing the measurements of DIY projects here, I've been somewhat disappointed, but this is right up there with Genelec in terms of performance, while being cheaper(to build). The 8330 cost more than this and measures worse.

For more context, let's compare it to one of the best values out there, the Neumann KH310:

Spins looks almost equal(honestly can't decide which I like more).
KH310 extends ~3Hz deeper, being -1.9dB at 37Hz.
Distortion @96 is close, but Directiva comes out on top. This is especially true if we assume the Directiva spikes are a product of the miniDSP vibrating on top and the 27kHz breakup.

The KH310 is an amazing speaker for the price, and one of the best values out there(if not the best) above $4,000. Not saying it assuredly sounds better than the KH310(I'm a huge fan of 3 way), but the fact that it arguably measures better for less than 1/3 of the price is amazing. Even at $4-5k full package price, I still think it's an incredible value. At 96dB it measures as well or better than the 708p and KH310, which are both in that same range.

I get that it's expensive, but at $1400 to build, this thing is a steal, and a huge win for DIY. The DIY designs measured up to this point have been bad to good in terms of value, but never exceptional. This is the first DIY design I've seen that really makes me want to try it.

 

[richard12511]

Note the negative sign of the PEQ.
This is the "baffle step correction" for the woofer. The PEQ reduces the sound pressure level of the frequencies that are still radiated by the driver as in the half-space (baffle is "large" in relation to the wavelength).



Nope, that is why Rick still needs to do some fine tuning.



With these tweeters you would have to change the name of the speaker in any case



LOL!
If this was not meant as a joke, you should read the thread again



See post#123, in the low frequency range, one reaches approximately the sound pressure level of two "normal" 6-6.5'' drivers.
If these two normal drivers use a BR port instead of a PR, they are at a slight advantage, with the usual disadvantages of a BR concept.

Cool to hear you say you can't design by measurements alone. These already measure as some of the best 2 way speakers we've seen.

If Rick hears a change that he rates subjectively higher, but measures worse, how do you plan to balance that?

 

[ROOSKIE]

I suspect economy of scale comes into play. economy of scale comes into play at such prices. Hard to imagine trying to compete with Amir approved speakers around that range for example. But maybe not.

come to think of it…funky/creative designs, like using a compression driver with massive wave guide (a la JBL studio 530) may be one way to get more out of less expensive drivers. Or open baffle designs that drive down cabinet expense. Or KEF Ref / Vandersteen style of mid bass and bass in separate compartments with a dipole amt. if you could figure an economical way to handle the cabinetry (such as modifying a parts express box or two to stack). Or 3D print a giant honking wave guide.

Indeed if anyone has access to a cnc router one could do amazing things with a corian baffle with built in wave guides. So long as you don’t factor in time and tooling/equipment costs.

This Directiva is a truly great measuring stand alone monitor. Superb really.

As far as $300.
If you were using subs, there are quite a few other drivers that likely can compete well and be a part of a speaker ASR would be proud of.
I actually think that going bass limited to a sealed design, designed to be crossed at 80hrz, one could nudge that $300 a pair mark.
Use the very same tweeters, they are $160pr USD
Make your own box (and for many drivers this will be a very small box, requiring minimal bracing and very easy to construct), use inexpensive connectors like the ones used here, and select from a handful of worthy contenders for woofers that cost $100-150 a pair (or even less if you can accept some minor compromises).
Again this type of design is only for use with subs although several drivers out there can play with some good output below 60hrz in sealed-smallish boxes if needed to.

Even using the Purifi sealed you would save some cash and likely be able to use it in an even smaller box.

That is the thing about DIY, there some options not really available in HiFi shops.

I get that it's expensive, but at $1400 to build, this thing is a steal, and a huge win for DIY. The DIY designs measured up to this point have been bad to good in terms of value, but never exceptional. This is the first DIY design I've seen that really makes me want to try it.

It is a superb speaker, I do see the BMR is another example of a great option for a similar price DIY and it does only require 1 amp. (I realize ASR did not test it.)
Most of the DIY testing has been on the more budget side so far. (or in the case of previous Purifi designs a cluster F of poor choices)
I think most DIY folks will say that due to the typical retail market being full of very strong budget finished speakers, ($300-750 retail) the really sweet spot for DIY monetary value is in the more expensive stuff.
Spending more time and money on Making a run at the $5k stuff.
Of course the real value in DIY IMHO and it MUST be said, is not saving money, rather gaining skills and learning. Even making a very average kit based speaker is a great learning experience and there is no substitute.
Often it is easy to tell the difference between people who have and people have not whenever these reviews roll out.

Anyway the main point for me is that Open Source Designs can work when the folks at ASR team up.
Like I stated to many times now, I'd love to see some less expensive options now that the capability is proven. I love DIY and so to see this site upgrade DIY across the board with a friken Klipple NFS and wide talent in hand, is a fantastic thing.

 

[musicforcities]

A lot of work was done to keep the surround flat like KEF.

Lol. No tangerine wave guide, instead we get fusilli screen. $240 each driver. Though I chuckled at the review by some dude who cannibalized the amp/dsp/etc from an ikea/Sonos speaker to use with it.

Right now The KEF 350 are listed fir $750 a pair. So the drivers alone would be 2/3 the cost of a finished pair. maybe one can DIY make a better measuring speaker that the 350 for the remaining $270 for hardware, finish, cabinets and crossover (if passive) and we don’t count labor). Those KEF engineers seem to earn their pay though.

All I am saying is that the Directiva is amazing and impressive and a feat at $1k and as others have noted bests many much more costly designs. The excellence speaks for itself.

No need to value engineer it. Indeed, not only is it good value, it makes me appreciate more the value presented by some manufactured speakers. The directiva demonstrates that DIY can now be about high-end quality and value.

 

[ROOSKIE]

Lol. No tangerine wave guide, instead we get fusilli screen. $240 each driver. Right now The KEF 350 are listed fir $750 a pair. So the drivers alone would be 2/3 the cost of a finished pair. maybe one can DIY make a better measuring speaker that the 350 for the remaining $270 for hardware, finish, cabinets and crossover (if passive) and we don’t count labor). Those KEF engineers seem to earn their pay though.

All I am saying is that the Directiva is amazing and impressive and a feat at $1k and as others have noted bests many much more costly designs. The excellence speaks for itself.

No need to value engineer it. Indeed, not only is it good value, it makes me appreciate more the value presented by some manufactured speakers.

People asked about potential Coaxial drivers.
I would never buy them myself.
KEF does have the market cornered. I think they have all the "good" coaxial patents and so others are hamstrung.
I think value engineering is part of the fun for many in the maker communities, most of the DIY guys are not really talking $ for moneys sake. Rather we/they are simply enjoying the classic discussion of the best $20 bottle of wine and best $200 bottle.
The Purifi IS special and IS especially expensive (and factor in the required PR's for small cabs)

Anyway as my previous post said don't DIY to save money. Do do it for other reasons.

 

[617]

Hole? Dead?

We must be looking at different measurements. This is probably one of the 3 best 2 way speakers we've ever seen. There is a very slight directivity increase, but it's fantastically tiny. 90%+ of speakers have a much worse dip.



Comparing side by side with the 708p, this speaker digs about 7Hz deeper. 708p is down 1.9dB at ~47Hz; Directiva is down 1.9 at ~40Hz. Comparing the distortion side by side at 96dB:

View attachment 157232

Directiva has much better 96dB distortion performance where it actually matters. 708p has lower bass distortion where we can't really hear it. I'm assuming those 2 spikes seen on the Directiva graph aren't real(in the sense that they exist in the real listening situation). 708p might look better at 106dB(guessing), but 96dB is already loud enough for most, especially for a speaker this small.

Looking at the spins:

View attachment 157234

Directivity is about equal, but the Directiva is clearly better in terms of frequency response.

The Directiva is ~$1350 to build, while the 708p is ~$3,800(on Sweetwater with big sale, normally $4,600). I own the 708p, and I think it's amazing for the price, but this speaker looks even better(at least at 96dB). Seeing the measurements of DIY projects here, I've been somewhat disappointed, but this is right up there with Genelec in terms of performance, while being cheaper(to build). The 8330 cost more than this and measures worse.

For more context, let's compare it to one of the best values out there, the Neumann KH310:

Spins looks almost equal(honestly can't decide which I like more).
KH310 extends ~3Hz deeper, being -1.9dB at 37Hz.
Distortion @96 is close, but Directiva comes out on top. This is especially true if we assume the Directiva spikes are a product of the miniDSP vibrating on top and the 27kHz breakup.
View attachment 157235

The KH310 is an amazing speaker for the price, and one of the best values out there(if not the best) above $4,000. Not saying it assuredly sounds better than the KH310(I'm a huge fan of 3 way), but the fact that it arguably measures better for less than 1/3 of the price is amazing. Even at $4-5k full package price, I still think it's an incredible value. At 96dB it measures as well or better than the 708p and KH310, which are both in that same range.

I get that it's expensive, but at $1400 to build, this thing is a steal, and a huge win for DIY. The DIY designs measured up to this point have been bad to good in terms of value, but never exceptional. This is the first DIY design I've seen that really makes me want to try it.

OK, that puts the performance in perspective. Thanks for drawing this comparison up.

My extensive DIY experience comes from the day when the basic approach was large box + fanciest drivers possible + on axis measurements + passive networks. This speaker is really a new approach to DIY, and shows the advantages of the NFS, the active topology and the Purifi woofer.

That distortion spike, by the way, doesn't show up in the purifi data and I doubt a PR would give you such a high Q distortion spike.

I guess what I keep asking for and not seeing is subjective impressions. Does this speaker have bass impact? Is it dynamic? Compression issues? Normally I don't care for subjective impressions but this is such an unusual driver I feel like I need someone to put it in perspective. Someone said the bass is equivalent to a 2x6" woofer speaker, which is helpful; this little speaker sounds like a small floorstander. Does that mean an mtm would sound like a 2x8 woofer speaker? You get the idea.

 

[tktran303]

Great job @amirm ; @ctrl ; @Rick Sykora

This is a great outcome for a first trial collaboration between measurers, crossover designers and builders.

It’s seem to have started a discussion; some people like it and some people don’t; so you’re obviously doing the right thing.

It’s a outstanding outcome for a 1/2cu ft speaker; and this is how it should be judged.

Remember; there is no EQ boost for the bass end- with further EQ and limiters @ctrl could have tweak the low end for even more output or
deeper bas (or less depending on desired placement attributes.

I suspect that the design brief was to be able to use it to construct a passive crossover with similar performance.

But this speaker has the clarity; power or resolving ability of a speaker like Genelec 8050B; which is a bigger speaker.

Put up the graphs side by side and compare for yourself- at 96dB the Directiva outperforms it!

I’ve said it before and I’ll say it again; this Purifi 6.5” has the bass of a 8” and the midrange clarity of a 5”. And all this in a small box.

 

[617]

Anyway as my previous post said don't DIY to save money. Do do it for other reasons.

I would reiterate that. God knows how much I've spent on DIY speakers...enough to buy something really nice I'd expect.

DIY has been a lot of fun, but at a certain point you find yourself sanding a cabinet for the 20th time and wondering what you're doing with your life.

 

[617]

@ctrl @Rick Sykora how hard was it to get NFS measurements into VCad? Any major issues there?

 

[Beershaun]

Congrats to the team! I love seeing this collaboration. I am very impressed with the smoothness of the woofer and the spl it delivered in Amirs tests. If I'm not mistaken this bookshelf style speaker is putting out the same spl as large floor standing speakers at the test power levels.

 

[garbulky]

So, I take it this is good? Amir, can you compare it to any other speakers?

 

[Arc Acoustics]

Nice one!
It's mostly done by the relatively good DXT waveguide and excellent woofer, so I should say the project itself is not quite impressive for me other than easiness of build and budget though.

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

I know a guy who got this kind of frequency response and score with passive crossover in a pittance, around 300 bucks (30k yen more precisely) including tie-rap(generic cheapies) and double-sided tape.

 

[mcdn]

[...] I guess what I keep asking for and not seeing is subjective impressions. Does this speaker have bass impact? Is it dynamic? Compression issues? Normally I don't care for subjective impressions but this is such an unusual driver I feel like I need someone to put it in perspective. Someone said the bass is equivalent to a 2x6" woofer speaker, which is helpful; this little speaker sounds like a small floorstander. Does that mean an mtm would sound like a 2x8 woofer speaker? You get the idea.

@617 you might be interested in this post from a while back giving subjective impressions of the same woofer in a similar (though sealed) speaker: https://www.audiosciencereview.com/...sma-prototype-unscientific-impressions.18242/

In short, yes it can do impact, punch, etc. The Directiva has a very flat response so if you're like me you would probably want to dial in a bit of boost below 200Hz

 

[Tangband]

Well done guys, very impressive. Pretty much blows every other 6.5" 2-way out of the water.

One thing that I think might be really worthwhile, however, is to do this same process, but use a more economical woofer. Nothing really wrong with the tweeters, but the use of $370 woofers limits the market for this to some degree. It might be interesting to explore a similar project using a Seas or SB Acoustics woofer, sacrificing some bass distortion performance for cost. Perhaps the ER18RNX or the equivalent size SB / Satori woofer.

The Purifi woofers are probably the best on the market... but they're still really, really expensive for a 6.5" driver.

I have used seas er18rnx and w300 waveguide with a scanspeak radiator in my active dsp loudspeaker HYBRID.
Crossover at 2,3 kHz 24 dB/oct Linkwitz Riley . They sound and measures very similar to my Genelec 8340.
HYBRID is a closed box loudspeaker made to play with dual subwoofers crossed at 80 Hz.
Knowing er18rnx very well, it has low distortion in the bass, but not at the same low level as the purifi midbass.

 

[aac]

with a passive crossover (i am a fan of active, but is not very easy to get on a cheap (under USD10K) multichannel setup.

A multichannel sound card for your PC will do the trick.