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ASR Directiva Open Source Speaker Review

Rick Sykora

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If I'm not mistaken the Denovo cabinet is only 'off-the-shelf' in the USA. Buying this cabinet and having it shipped to Europe, for example, would probably cost nearly as much as getting a similar cabinet custom built by a local cabinetmaker. And really, if someone can't cut six pieces of MDF square and glue them together they probably shouldn't be considering DIY in the first place. Since the majority of ASR members are not in the USA, the off-the-shelf requirement of Directiva is a bit unnecessary IMO as most potential builders will be building from scratch anyway ...
Yes, the off-the shelf cabinet is a convenience item.

There were a few factors that influenced the move away from the custom cabinet:

1. There was apparent midrange leakage to the PRs and I did not find a simple solution.
2. Was using the Purifi PRs and they drove the cost even higher. 2 of them is almost as expensive as another woofer.
3. My wife (who initially liked) saw it on the stand and thought it was ugly. Later, I have to admit it was not my favorite.

Figured if the rectangular cabinet really was challenged, could resurrect the angular one. It turned out pretty good after all. :)
 

dukanvadet

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Considering the thoughtful criticism from the readers and helpful insights from the designers I look forward to all the improved versions! Until then i can only say thank you so much to rick and ctrl for the work you have provided for the community. A completed product is always a set of compromises and as far as i can see as an amateur speaker builder I think they are well choosen and excecuted in this design.
 
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bluefuzz

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My wife (who initially liked) saw it on the stand and thought it was ugly. Later, I have to admit it was not my favorite.
Yes, for a smallish bookshelf speaker æsthetics and convenience are every bit as important as sound quality. Otherwise we would all be building refrigerator sized floorstanders anyway. I'm certainly not arguing for the coffin shaped design – I would never build such an ugly box regardless of how good it may sound. But for any design I don't see the need for it to be compromised by off-the-shelf boxes as they are unlikely to be available to more than a fraction of the potential builders anyway. Better to design an optimal (and æsthetically pleasing) cabinet and let people figure out how to build it. There are online suppliers that can cut MDF, plywood, and more exotic materials to size, as can most home-improvement stores, which is essentially the same as a flat-pack.
 

somebodyelse

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If I'm not mistaken the Denovo cabinet is only 'off-the-shelf' in the USA. Buying this cabinet and having it shipped to Europe, for example, would probably cost nearly as much as getting a similar cabinet custom built by a local cabinetmaker. And really, if someone can't cut six pieces of MDF square and glue them together they probably shouldn't be considering DIY in the first place. Since the majority of ASR members are not in the USA, the off-the-shelf requirement of Directiva is a bit unnecessary IMO as most potential builders will be building from scratch anyway ...
https://www.soundimports.eu/en/denovo-audio-300-7064.html
They're available from at least one supplier in Europe, and the price differential isn't that big. I don't know about other parts of the world.

Having said that, if you're up to the task of routing the driver cutouts you shouldn't have any trouble making a simple box.
 

TLEDDY

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“Since the majority of ASR members are not in the USA...”

Is this statement correct?
 

Acoustician

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In the original post #1:
That is less than half than what a KH310 or 8341 cost which makes the rest of your post and comments invalid.

This is likely where most of the confusion comes from. The Directiva at least to this point, is an open DIY design and not a product you can purchase. It would seem that there is in fact only a single speaker in existence so far, so criticism of it as a "product" is premature :)

Oh, that makes the whole conversation (non)sense.
What I commented was "the commercial implementation" in the post #1.

400-500 grand a pair (according to the 1st post)
By the way, 4-5 grand a pair, not 400-500 grand stupid high-end obviously.
 

TimVG

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If I'm not mistaken the Denovo cabinet is only 'off-the-shelf' in the USA. Buying this cabinet and having it shipped to Europe, for example, would probably cost nearly as much as getting a similar cabinet custom built by a local cabinetmaker. And really, if someone can't cut six pieces of MDF square and glue them together they probably shouldn't be considering DIY in the first place. Since the majority of ASR members are not in the USA, the off-the-shelf requirement of Directiva is a bit unnecessary IMO as most potential builders will be building from scratch anyway ...

It's available from soundimports in Europe.
 

Sancus

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@amirm Question regarding the distortion charts:

In the spinorama, this speaker is almost flat to 40hz. But in the distortion charts, it's down 8dB by 40hz from the stated level(ie 78dB in the 86dB chart). Why is that?
 

mtg90

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I'm guessing the distortion measurements are a single measurement taken at 1m at the desired output level, which is why the measured frequency response deviates some from the rest of full scan NFS data.
 

kencreten

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Amazing work!
takemymoney.jpg
HA!
 

tvrgeek

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Just saw this thread. I was considering a similar build myself. I have used the DXT tweeter several times with success, but also looking at the CSS or the Satori ring dome ( a bit more pricy though). I have yet to really study the design and testing results, but my recent tests concluded the importance of phase between the drivers through the midrange and crossover. So much more to a speaker than just tonality, but amazing as has been pointed out, how many fail that most basic requirement!

I would add a radius to the top edge and offset the drivers. Diffraction matters. Not into odd shaped boxes, but doing what we can in a conventional box is audible.
 

tvrgeek

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As a long time speaker builder:
Nearfield driver measurements are useless once one has chosen them. Just as useless an anechoic measurements. 1M and further in the prototype box in a "reasonable" room is all that matters as that is how we use them.

I'll match my passive crossover skills over a Mini-DSP any day for musicality. Actually 90% of a speaker design is crossover. If active and DSP, then you are just slapping a couple drivers in a box. Any 14 year old can do so.

Anyway, fun project, let's see where it goes. Be very carful in the eq for both the tweeter around crossover and the woofer below Fb. All to easy to exceed 1/2 X-max where distortion skyrockets. I would start by perfecting the baffle dimensions and layout. Measure the AC offset and go from there. With DSP, you have a potential to remain in phase through the crossover and critical midrange which does wonders for imaging.
 

TimVG

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You've obviously not gone through the design thread. This speaker was developed around certain constraints and a lot of work was done to maximize performance within said constraints. This was not only done through building and measuring, but also meticulous simulations using ABEC. The measurements were more of a sanity check as performance was already well predicted beforehand.

Also:
Nearfield driver measurements are useless once one has chosen them. Just as useless an anechoic measurements. 1M and further in the prototype box in a "reasonable" room is all that matters as that is how we use them.

I'll match my passive crossover skills over a Mini-DSP any day for musicality.

You're in the wrong forum for this kind of nonsense.
 

tvrgeek

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You've obviously not gone through the design thread. This speaker was developed around certain constraints and a lot of work was done to maximize performance within said constraints. This was not only done through building and measuring, but also meticulous simulations using ABEC. The measurements were more of a sanity check as performance was already well predicted beforehand.

Also:


You're in the wrong forum for this kind of nonsense.
Actually I did, and having about 45 years of experience building high end speakers, I actually have some background on this. Where the objective measures as presented are informative, they do not tell the entire story. I offered a couple suggestions based on this experience.

Again, as I clearly stated, this is a fun project direction and I would like to see where it follows.

I too use as many simulation tools as I can afford as it reduces the number of prototypes many times. I too use use as many objective measures of my prototypes as again, it reduces the number of iterations. But in all that, I know for a fact, models only go so far as do objective measures. There is always the final tune by ear as your ears and your room are not the same as mine. Science. I will say, I can hit my cabinet design in a couple of days, so not impressed there. I prefer passive crossovers and that can take me 6 months at least. Not that I object to DSP, just all I have tried, including MiniDSP and Behringer, have been very disappointing. I will be testing Dirac on my living room soon as I have a broad midrange dip that is not practical to resolve in the passive domain.

An advantage if DIY, is we can do things that are labor intensive or to personal bias that are not practical in the mass market. An example is an asymmetric baffle. In a commercial product, that raises the cost. Not for a DIY. We can evaluate the actual drivers and tune ( with DSP if needed) to the actual drivers as manufacturing tolerances vary greatly. We can even afford to re-tune after a period of break-in as drivers change quite a bit and not always predictably. Depending on your woodworking skills, one can make very non-resonant cabinets that would be cost exclusive in volume. I can also suggest some alternative materials that are even better than MDF. With CNC, we can do thigs almost impossible before and would take too long in production. Anyone who is a woodworker knows about the various difficulties in finishing MDF which can me mitigated by DIY, but difficult in production. Things like PVA shrinkage.
 

thewas

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Actually I did, and having about 45 years of experience building high end speakers, I actually have some background on this.
Just out of curiosity, could you please post some of these loudspeakers and some of their corresponding
I too use as many simulation tools as I can afford as it reduces the number of prototypes many times. I too use use as many objective measures of my prototypes
 
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Rick Sykora

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Directiva is a project platform and is meant to be modified and improved upon.

Anyone who thinks they can do better is welcome to contribute to one of the r1 crossover design threads, join a future project or start one of their own.

Thanks!

Rick
 

fluid

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An advantage if DIY, is we can do things that are labor intensive or to personal bias that are not practical in the mass market. An example is an asymmetric baffle. In a commercial product, that raises the cost. Not for a DIY.
I agree wholeheartedly with the first statement but given that this design targeted directivity as a primary focus, adding twisted lobes from asymmetric positioning would be an odd choice.

https://www.prosoundtraining.com/2013/01/25/tweeter-placement-two-way-loudspeakers/

An asymmetric baffle doesn't mean asymmetric positioning but the two often go together particularly in a two way.
 
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