Directiva r2 monitor prototype build

[gnarly]

Great Rick, glad my comments fit in.
Very nice project, looking forward to developments,
If, for active processing settings, you decide to try FIR as well, I'd be happy to build FIR files from whatever raw drivers' measurements (or averages) ......that you'd like corrected, along with various linear phase xovers you specify... just lemme know if...

 

[Rick Sykora]

Team is still quite busy with improving our measurement rig but felt I should share that we have agreed that the first r2 speaker will be more of a 3-way stand-mount design. Our goal to keep costs lower than r1 are intact, so likely means the midwoofer and tweeter filters will need to be passive.

This should simply some of the integration effort and allow me to build an r2 speaker worthy of Amir's test effort. Expect the design will evolve further before it is ready for me to build. Still planning to improve price/performance significantly beyond r1. For smaller applications, expect the first prototype may be good enough but currently only have bandwidth for one speaker.

 

[TimVG]

Just a little bit of background: Since loudspeakers outside of my dedicated room in this house have to be somewhat discreet, and since I have two Hypex FA253 left which I'd like to use, I told the team I would like to build a version which would incorporate both the top module and the bass module in a standmount design. Luckily, they seemed interested so we can do this within the public scope of the R2 project.

This will not be a drastic change from what was done already, the separate bass enclosure will simply be very small and not-so-seperate. The design goal for myself is an anechoic response to 80Hz (Q = 0.7). This will be fully customisable by the user though, so you'll be able to adjust the system to your specific situation.

This version is a compromise in itself in terms of output (although a reasonable one, since many of you have already asked for something like this/numbers will be made available when they are available) and extension. Don't expect any low bass unless you listen at very moderate levels. Output should be more than reasonable when combined with a sub.

My personal version will be a fully active 3-way, but as Rick mentioned, a passive filter between mid and tweeter is also in the works.

If I can finish in time, I plan on hosting a listening session of this system along with a couple of small subs for those of you willing to make the drive (Belgium, EU)

 

[abdo123]

This will not be a drastic change from what was done already, the separate bass enclosure will simply be very small and not-so-seperate. The design goal for myself is an anechoic response to 80Hz (Q = 0.7). This will be fully customisable by the user though, so you'll be able to adjust the system to your specific situation.

Is the bass enclosure so far going to be a sealed regular design or a ported cardioid?

Has a driver been chosen for the module?

 

[TimVG]

Standard sealed. Makes crossing to subs a bit more straightforward. Driver I'll be testing is this Peerless 6.5"as I need the truncuated frame to fit within the width of the original R2 module. Driver may still change, but it is a good candidate.

 

[Trouble Maker]

FA253

I 100% get why the team is doing a 2 channels of DSP and amp/side. But it's also easy to imagine the 3 channel plate Hypex DSP plate amps being perfect for this.

Are there any user configurable DSP systems (like miniDSPs or these Hypex plate amps) which enable dynamic boosting/compression of the signal based on frequency? I'm not sure if that's the right terminology. What I mean is many OEMs making active speakers artificially boost low Freq. at lower volumes to give more extension, but then limit after some limit in the speaker is hit. This would be a cool feature for the DIY community!

 

[D!sco]

Did they finish the Atlantic bridge yet? I’ll see you in 6k miles, Tim! I just need to pack some oars.

 

[abdo123]

@TimVG Will you need to build new cabinets from scratch for the FA253? Or are you planing to make space for it somehow?

 

[TimVG]

New cabinets to accomodate both the bass driver and the hypex amp. Top part will be similar to current version.

 

[abdo123]

New cabinets to accomodate both the bass driver and the hypex amp. Top part will be similar to current version.

Well if you happen to not need the ones you already built, i would be more than happy to buy them.

 

[TimVG]

Well the current version will remain in my listening room as-is. These new ones are extra for the living room

Happy to provide templates or files when the project is finished. I'm in early talks with a small local shop to produce some flat packs in summer.

 

[abdo123]

as I need the truncuated frame to fit within the width of the original R2 module.

I have a small comment on this. Since the crossover frequency is relatively low, can you put the driver on the side ? (still below the midrange)

If someone would like to use a wider bass driver.

@ctrl @Rick Sykora

 

[Rick Sykora]

I have a small comment on this. Since the crossover frequency is relatively low, can you put the driver on the side ? (still below the midrange)

If someone would like to use a wider bass driver.

@ctrl @Rick Sykora

This has been discussed already, but would have major effect on directivity. Am busy on another project, so will leave to @TimVG or @ctrl to elaborate.

 

[ctrl]

can you put the driver on the side ? (still below the midrange)
If someone would like to use a wider bass driver.

A bass module with side-mounted drivers is counterproductive to our efforts to control the radiation, especially the lateral radiation, as far as possible down to low frequencies.

Side-firing woofers in the bass module would produce lobes with maximum sound pressure level at +-90°, as a simple simulation quickly shows.

Simulation of a side-firing 10'' woofer in a bass module, viewed from the side. The listening axis is therefore at hor -90° - the blue curve. The radiation to the side is shown by the orange curve (hor and ver 0°), brown curve is backward radiation (+90°):

Even at 200Hz, the difference between side and front radiation is still around 3dB. So we would end up with "lateral lobes" which would counteract our effort to limit the lateral radiation.

So, side woofers come with a price, whether it is worth it, everyone must decide for themselves. Perhaps it is possible to push the crossover frequency down to 150Hz, then the widening in the radiation should begin only from around 200Hz and below.

 

[nc535]

My tongue in cheek advice is not to use side woofers on a what is intended to be a passive cardioid. I think side woofers only work as subwoofers where they are omnidirectional but even with dual opposed side subwoofers, the radiation to the side, iirc, may be 3 db greater than to the front and dual opposed subwoofers leads to a fairly wide cabinet. I think the best solution for deeper bass is simply to stack up the woofers.

 

[abdo123]

My tongue in cheek advice is not to use side woofers on a what is intended to be a passive cardioid. I think side woofers only work as subwoofers where they are omnidirectional but even with dual opposed side subwoofers, the radiation to the side, iirc, may be 3 db greater than to the front and dual opposed subwoofers leads to a fairly wide cabinet. I think the best solution for deeper bass is simply to stack up the woofers.

It’s just my mind can only justify so many drivers for something that you would need to cross to a subwoofer at the end. Specially since my space is not big in anyway.

I thought maybe i can increase extension and do less steep crossovers to justify it (as a way to become less dependent on excessive digital processing for bass management) but it doesn’t seem like a good idea.

But you know i get random ideas all the time, and i appreciate other members input on them.

 

[Rick Sykora]

It’s just my mind can only justify so many drivers for something that you would need to cross to a subwoofer at the end. Specially since my space is not big in anyway.

I thought maybe i can increase extension and do less steep crossovers to justify it (as a way to become less dependent on excessive digital processing for bass management) but it doesn’t seem like a good idea.

But you know i get random ideas all the time, and i appreciate other members input on them.

May just have to wait a bit longer until we can circle back and see how much output we can get from the initial proto. My initial directivity measurements with the sealed version look slightly better than r1. I have some other projects to deliver but plan to measure it with the slotted sides soon. After that, the project progress will depend on Tim’s bandwidth.

 

[TimVG]

Passive resistance cabinet systems are quite easy to start, but tricky to get right, it's a delicate balancing act. Since we do eventually want to complete this project, and results with the top module have met/exceeded expectations, radically changing our approach won't help continuity. Now, in my opinion - the 3-way version (with the 6,5" fillter driver) is a practical and cost-effective solution if you are looking to cross to subwoofers. R2 was always going to be a 3-way system, so in that sense, nothing has changed.

 

[julbo]

I 100% get why the team is doing a 2 channels of DSP and amp/side. But it's also easy to imagine the 3 channel plate Hypex DSP plate amps being perfect for this.

Are there any user configurable DSP systems (like miniDSPs or these Hypex plate amps) which enable dynamic boosting/compression of the signal based on frequency? I'm not sure if that's the right terminology. What I mean is many OEMs making active speakers artificially boost low Freq. at lower volumes to give more extension, but then limit after some limit in the speaker is hit. This would be a cool feature for the DIY community!

I'm testing right now a 3E Audio SY-DAP2002 alongside a MiniDSP HD with the Directiva r1. IMHO it's a cheaper (and lower performance/connectivity) DSP amp combo alternative to a FA-122 if you don't mind tinkering a bit

 

[Morpheus]

Is anybody around ASR trying the extended directivity goal going from the R1 template or other high price/SOTA specs driver aiming for the best with less price constraints?