Introducing Directiva - An ASR open source platform speaker project

[TimVG]

Alright. The drivers are pretty much 'confirmed' at this point right?

Yes, pretty much. While they seem like obvious standard choices, for the woofer alone we considered over two dozen models, so we didn't go over this choice lightly
These drivers just perform really well for the money.

 

[abdo123]

Yes, pretty much. While they seem like obvious standard choices, for the woofer alone we considered over two dozen models, so we didn't go over this choice lightly

Alright. I might consider purchasing them already since in 2022 you never know when something goes out of stock. forever.

 

[TimVG]

Alright. I might consider purchasing them already since in 2022 you never know when something goes out of stock. forever.

I wouldn't worry too much about that since these are quite popular drivers, and we intend for people to be able to actually build this model.. But sure, I understand if you'd like to order sooner than later

 

[McFly]

Yes, pretty much. While they seem like obvious standard choices, for the woofer alone we considered over two dozen models, so we didn't go over this choice lightly
These drivers just perform really well for the money.

The SB15NBAC30 really is a jack of all trades woofer. Amazing little unit.

 

[muad]

How about now?

So as Rick already mentioned. This is a prototype - so is the crossover which I implemented in maybe 10 or 15 minutes. Please view this as the top module (2-way) of a larger system (3-way).

Damn, I think I may just have to build this. This is definitely an opportunity to try affordable cardioid dispersion!

 

[Colonel7]

Any details on the bass module(s) close yet?

 

[Rick Sykora]

Any details on the bass module(s) close yet?

Not really TBH. Team has done some spitballing but that is about it....

The smaller tower one is likely to have a vent or a PR to get enough extension.

The bigger one is still targeted to be sealed and have discussed potential drivers, but nothing firm as yet.

 

[ppataki]

Amazing work! I think @ppataki would approve of the Raptor-coating. I am definitely looking forward to the progress and am very impressed so far!

Yes, totally!!
Here it is: https://audiosciencereview.com/foru...-corner-line-array-project.25983/post-1044700

 

[TimVG]

Damn, I think I may just have to build this. This is definitely an opportunity to try affordable cardioid dispersion!

And with both an active and active/passive hybrid in the works (and perhaps even a fully passive version), it should prove to be a very versatile system.

 

[hege]

A tall 2x12" base for it would make it very interesting 1237A alternative.

 

[TimVG]

A tall 2x12" base for it would make it very interesting 1237A alternative.

It should provide better directivity, but I highly doubt it will play as loud

 

[abdo123]

It should provide better directivity, but I highly doubt it will play as loud

Speaking of which, any idea what the sensitivity is roughly with the crossover you did?


I'm very scared that it will dip below 80dB/2.83V @ 200Hz because of the baffle step and cancellation.

 

[TimVG]

Speaking of which, any idea what the sensitivity is roughly with the crossover you did?


I'm very scared that it will dip below 80dB/2.83V @ 200Hz because of the baffle step and cancellation.

To be determined.
Since this was an active crossover there is no real system sensitivity. But your remarks are quite correct, this is why a passive/active hybrid seems interesting. We not only have to account for the top module, but also different bass modules, which will have variable degrees of sensitivity. A passive/active hybrid has the advantage of being able to drive the system from a basic miniDSP 2x4 unit and use signal shaping on both the bass unit, as well as the top module. A fully active system would require 3 channels per speaker. (or if one would be after extended directivity down to the bass range by means of an active cardioid bass module, 4 channels per speaker).

 

[abdo123]

To be determined.
Since this was an active crossover there is no real system sensitivity. But your remarks are quite correct, this is why a passive/active hybrid seems interesting. We not only have to account for the top module, but also different bass modules, which will have variable degrees of sensitivity. A passive/active hybrid has the advantage of being able to drive the system from a basic miniDSP 2x4 unit and use signal shaping on both the bass unit, as well as the top module. A fully active system would require 3 channels per speaker. (or if one would be after extended directivity down to the bass range by means of an active cardioid bass module, 4 channels per speaker).

If you have an oscilloscope lying around it would be interesting to see what output you have at 200Hz @ 2.83V with a ground plane measurement.

I think most people would be interested in at least getting ~100 dB to 105 dB of peak output @ 1 meter with realistic amounts of amplification (~100 to 300W with [email protected]).

 

[Colonel7]

(or if one would be after extended directivity down to the bass range by means of an active cardioid bass module, 4 channels per speaker).

Is that something you'll be trying eventually?

 

[TimVG]

If you have an oscilloscope lying around it would be interesting to see what output you have at 200Hz @ 2.83V with a ground plane measurement.

I think most people would be interested in at least getting ~100 dB to 105 dB of peak output @ 1 meter with realistic amounts of amplification (~100 to 300W with [email protected]).

I don't have oscilloscope - and the weather (+my schedule) isn't really allowing me to do any GP measurements anytime soon.
I've overlayed the SB on-axis from the IEC baffle (factory) measurements with the on-axis from the driver in the cabinet.

So you're looking at a 4dB loss in comparison.

 

[TimVG]

Is that something you'll be trying eventually?

The bass module(s) are being designed by other members, so while I can't speak for anyone but myself, I'm a bit sceptical about the added value of controlled directivity in the modal range of a room, so I won't be building one for myself. There may be others who will design such a module. In an active configuration, it's quite easy to execute really. It has been done in the PA world for many years.

 

[abdo123]

I don't have oscilloscope - and the weather (+my schedule) isn't really allowing me to do any GP measurements anytime soon.
I've overlayed the SB on-axis from the IEC baffle (factory) measurements with the on-axis from the driver in the cabinet.

So you're looking at a 4dB loss in comparison.

View attachment 178164

Thank you for sharing, I hope you didn't take any offense with my comments, I'm just very interested in the design.

I very much recommend this oscilloscope if you're interested in buying one, it's a bit on the cheap side but very effective for our use: https://www.aliexpress.com/item/4000717577838.html?spm=2114.12057483.detail.3.54772fcaM5KFZq

it might be even more interesting in the future to get one incase you want to mix amplifiers you have already around for an active crossover design.

 

[TimVG]

Thank you for sharing, I hope you didn't take any offense with my comments, I'm just very interested in the design.

I very much recommend this oscilloscope if you're interested in buying one, it's a bit on the cheap side but very effective for our use: https://www.aliexpress.com/item/4000717577838.html?spm=2114.12057483.detail.3.54772fcaM5KFZq

it might be even more interesting in the future to get one incase you want to mix amplifiers you have already around for an active crossover design.

None taken

I do have a decent multimeter for measuring voltages.

 

[A_R]

The bass module(s) are being designed by other members, so while I can't speak for anyone but myself, I'm a bit sceptical about the added value of controlled directivity in the modal range of a room, so I won't be building one for myself. There may be others who will design such a module. In an active configuration, it's quite easy to execute really. It has been done in the PA world for many years.

Would it be an idea, to built a bass module more or less similar the Genelec W371?