Directiva r1 speaker build

[TheBatsEar]

I one have appropriate tool and could prepare a .dwg project - then in some cases it could be even cheaper to cut all pieces by local professional...

Found an online shop. Their price would be 70€ for two baffles without shipping, but i can't use their service, because they only can do 10mm radius on the baffle, not the needed 19mm. Darn.

If you can do it, i'd pay 70€ plus shipping for your service.

 

[TheBatsEar]

In fact, i would pay 110€ plus shipping for the whole kit. Not sure how many Zloty that is, maybe 500 or so.

 

[Rick Sykora]

Found an online shop. Their price would be 70€ for two baffles without shipping, but i can't use their service, because they only can do 10mm radius on the baffle, not the needed 19mm. Darn.

If you can do it, i'd pay 70€ plus shipping for your service.

The Denovo cabinet used for r1 has a 1/2 inch roundover. So about 12-13 mm.

 

[abdo123]

The Denovo cabinet used for r1 is a 1/2 inch roundover. So about 12-13 mm.

Doesn’t it come pre-roundedover?

Or am i missing something?

 

[TheBatsEar]

Doesn’t it come pre-roundedover?

Or am i missing something?

The Denovo kit? I don't think so.
Seems so:

Denovo Audio Regallautsprecher | 15,9 L | Flatpack kaufen

Bestellen Sie den 300-7064 online bei SoundImports ✓ Versand am selben Tag ✓ Niedrige Versandkosten

www.soundimports.eu

 

[julbo]

I’d love to do some mods on the cabinet if going full custom. Slanted bracing, thicker front panel with heavier chamfer around the tweeter, narrower/shorter and bit deeper for (IMO) aesthetics, replaceable back panel, thicker walls, HDF, colored, etc

 

[julbo]

The Denovo kit? I don't think so.
Seems so:

Denovo Audio Regallautsprecher | 15,9 L | Flatpack kaufen

Bestellen Sie den 300-7064 online bei SoundImports ✓ Versand am selben Tag ✓ Niedrige Versandkosten

www.soundimports.eu

I reckon you've finally concluded this steak does not exist

 

[TheBatsEar]

I reckon you've finally concluded this steak does not exist

Still tastes good, can't deny that.

 

[TheBatsEar]

Found an online shop. Their price would be 70€ for two baffles without shipping, but i can't use their service, because they only can do 10mm radius on the baffle, not the needed 19mm. Darn.

Can't input all the data as i need it there, screw it. I think i'll just get a simple box for now and get a proper front later. Maybe i buy or lend a router and do it in the bathroom, tit's the best place to keep dust in check.

The parts for two speaker in case someone will do the same. I have changed 217 to 218 as to not have fractions of a mm at the back. I think it's close enough to not kill the dispersion:

410 x 218 x 19 = 2x Front
410 x 270 x 19 = 4x Side
180 x 270 x 19 = 4x Top/Bottom
180 x 372 x 19 = 2x Back

This results in a box 410mm high, 218mm wide and 270mm deep. Inside is 372mm high, 180mm wide and 251mm deep, which is almost exactly 16.8 liter volume. Which can be reduced by using bracing and maybe shoving the back deeper in. I ordered at baumarkt-deutschland.de, 35€ for the MDF, 20€ for shipping.

Still waiting for the tweeters and some other stuff.

 

[julbo]

Starts to look like a cabinet, had a lot of small mistakes with the trimmer that will be unashamedly covered by a blanket of paint chamfered the radiator because I think it deserves a breathing room as well.
Loaded the baseline active XO into my new minidsp and ran a test drive with a cute little A07 @ 48V. Should say it sounds good even with no box and zero baffle.
I've read about people complain of A07 getting hot, in my case it's luke warm (albeit mono and not too loud) with the miniDSP getting actually hotter

 

[TheBatsEar]

Still waiting for tweeters, wood cuts and passive radiators.

 

[julbo]

Directiva R1 first dry run!!
First impression it sounds good, meaty bass, punchy, crisp highs. A bit of mid ear strain, will need to calibrate the xover to my specific drivers and acoustics. Will take me some time.
Issue 1 - There is some chuffing noise seemingly from the speakon connector going from 70Hz downwards. Initially I thought it was the radiator.
Issue 2 - Radiator seems a bit underpowered, seems to reach max mech excursion while the Purifi is still having a ball.
To do:
Try adding the (currently shorted) 30Hz high pass in the LF xover.
Pull out the radiator and recheck the internals. Replace radiator.
Run a sweep, this reveal all the bad resonances and FR.

 

[ctrl]

A bit of mid ear strain

In any case you should check by measurement if the filter slopes correspond to the desired LR filter fourth order at 2500Hz.

I would recommend to load the target functions (LR4@2,5kHz) for woofer and tweeter in REW as an overlay, then you can compare exactly with the VCAD simulations shown below:

tweeter with target HP LR4@2,5kHz


woofer with target LP LR4@2,5kHz



The VCAD simulation refers to a distance of 3m. If you measure at a distance of 1m at the height of the tweeter (this is the reference axis), then the FR of the woofer deviates minimally.
But the deviation is so small that this hardly matters.


If the filter slopes follow the target functions, but the resulting frequency response of the loudspeaker does not match the simulation, then you should check the delay set in the tweeter XO.

Radiator seems a bit underpowered, seems to reach max mech excursion while the Purifi is still having a ball

The passive radiator (PR) is, with the standard tuning in terms of max SPL very limited.

But by using the provided HP filter as a protection against too much excursion of the PR, the maximum SPL is almost arbitrarily adjustable, at the expense of low bass.

A fourth order Butterworth HP at 45Hz increases max SPL significantly. At the same time the f3 of the speaker is still at 45Hz, which is good for a speaker of this size.

Here is the comparison of the standard tuning without HP, with BW4@45Hz and BW4@50Hz.
First simulated max SPL in half-space, then excursion of woofer and PR:

standard tuning without HP (f3 about 38Hz), max SPL free field 95dB


BW4@45Hz (f3 about 45Hz), max SPL free field 100dB


BW4@52Hz (f3 about 53Hz), max SPL free field 104dB

At the 104dB peak level, however, the voice coil of the woofer is loaded with 400W , which the woofer certainly does not withstand very long.

Which HP frequency is chosen, everyone must decide for themselves.

 

[morpheusX]

Now off to do impedance measure to see whether this really is a twin to the one Amir has!

Could you please explain how you did the impedance measure?

 

[Rick Sykora]

Could you please explain how you did the impedance measure?

I use the REW impedance measurement rig with a SoundBlaster Audigy soundcard. From comparison to other tests, it is small signal. If you have more specific questions, let me know.

 

[morpheusX]

Thank you for your quick response.

REW documents the process here, and DATS is a complete package, but i was trying to understand if there was a cheaper and already made product that could be used

Edit: THIS might help others

 

[Rick Sykora]

In any case you should check by measurement if the filter slopes correspond to the desired LR filter fourth order at 2500Hz.

I would recommend to load the target functions (LR4@2,5kHz) for woofer and tweeter in REW as an overlay, then you can compare exactly with the VCAD simulations shown below:

tweeter with target HP LR4@2,5kHz
View attachment 197466

woofer with target LP LR4@2,5kHz
View attachment 197476


The VCAD simulation refers to a distance of 3m. If you measure at a distance of 1m at the height of the tweeter (this is the reference axis), then the FR of the woofer deviates minimally.
But the deviation is so small that this hardly matters.
View attachment 197478

If the filter slopes follow the target functions, but the resulting frequency response of the loudspeaker does not match the simulation, then you should check the delay set in the tweeter XO.



The passive radiator (PR) is, with the standard tuning in terms of max SPL very limited.

But by using the provided HP filter as a protection against too much excursion of the PR, the maximum SPL is almost arbitrarily adjustable, at the expense of low bass.
View attachment 197468
A fourth order Butterworth HP at 45Hz increases max SPL significantly. At the same time the f3 of the speaker is still at 45Hz, which is good for a speaker of this size.

Here is the comparison of the standard tuning without HP, with BW4@45Hz and BW4@50Hz.
First simulated max SPL in half-space, then excursion of woofer and PR:

standard tuning without HP (f3 about 38Hz), max SPL free field 95dB
View attachment 197469View attachment 197470

BW4@45Hz (f3 about 45Hz), max SPL free field 100dB
View attachment 197471 View attachment 197472

BW4@52Hz (f3 about 53Hz), max SPL free field 104dB
View attachment 197473 View attachment 197474
At the 104dB peak level, however, the voice coil of the woofer is loaded with 400W , which the woofer certainly does not withstand very long.

Which HP frequency is chosen, everyone must decide for themselves.

A couple of quick adds here as I realize I may need to better articulate some points…

Directiva r1 was targeted for a speaker hobbyist to tailor to their own needs. In particular, the default bass tuning is more flat and does push the passive radiator to achieve. This works well for most music when the speakers are on stands well away from walls. The HP filter was meant to protect the woofer from over-excursion, but as noted, the PR will reach its excursion limits more readily. While it can also be helped with the HP filter, if the speaker is to be used closer to walls, then the default bass tuning may be too aggressive and needs to be tweaked. As is placement and room dependent, tailoring the bass response is left to the builder. As previously mentioned, if you find the chosen PR to be a limiting factor, the dual Purifi ones allow for much more excursion but at a more premium price than our original design target provided.

Next, along with gasketing the speakon, should emphasize that the tweeter does not incorporate a gasket and should have one as well. I had some from older dome tweeters but tape is much easier to find. Along with the bass tuning will edit this thread to help future builders plan accordingly.

Finally, I realize that I should have created a user build thread. I will remedy this shortly and so expect that some content here will get moved. Ideally this would be a sub-thread that allows multiple individual builds to be managed, but will need to get some admin support to do.

 

[julbo]

A couple of quick adds here as I realize I may need to better articulate some points…

Directiva r1 was targeted for a speaker hobbyist to tailor to their own needs. in particular, the default bass tuning is more flat and does push the passive radiator to achieve. This works well for most music when the speakers are on stands well away from walls. The HP filter was meant to protect the woofer from over-excursion, but as noted, the PR will reach its excursion limits more readily. While it can also be helped with the HP filter, if the speaker is to be used closer to walls, then the default bass tuning may be too aggressive and needs to be tweaked. As is placement and room dependent, tailoring the bass response is left to the builder. As previously mentioned, if you find the chosen PR to be a limiting factor, the dual Purifi ones allow for much more excursion but at a more premium price than our original design target provided.

Next, along with gasketing the speakon, should emphasize that the tweeter does not incorporate a gasket and should have one as well. I had some from older dome tweeters but tape is much easier to find. Along with the bass tuning will edit this thread to help future builders plan accordingly.

Finally, I realize that I should have created a user build thread. I will remedy this shortly and so expect that some content here will get moved. Ideally this would be a sub-thread that allows multiple individual builds to be managed, but will need to get some admin support to do.

Thanks a lot @ctrl & @Rick Sykora for taking the time for the feedbacks. As this is my first DIY there's a lot to be learned To some extent it's a litmus test of the Directiva open source for the less initiated, appreciate a lot your patience and guidance.
My setup is far from ideal, I have constant noise in my neighborhood and from my household so I need to hide in my man cave. That is a 50sqm space 2.4m high, 1/3 packed with HT and gym stuff. For sure I cannot get a meaningful response for anything below 400Hz so I'm focusing on tweeter and xover region. 1m height spkr placed on an old B&W floorstander with padding, 1m distance to mic placed between HF and LF drivers. UMIK 1. MiniDSP HD. A07 amp. I ran REW with 75dB SPL reference pink noise.
The woofer is slightly deep into the recess, plan to raise it a bit with a cardboard gasket that also will tighten up air leakage. The air leaking in the speakon and PR was almost completely solved with a cardboard gasket and some wrapped acoustic barrier stuff.
I have a couple of major screw-ups that revealed themselves during the REW sweeps, without any further ado I welcome myself to the dark world of resonances
The tweeter recess (hole) diameter is too large, I have a 1 mm gap that creates a dispersion havoc with the FR (blue line). Did not imagine it is THAT bad. I figured 1mm is 300KHz so no worries, boy I was wrong, it's a ridge on the waveguide...
The sweep has no smoothing other than IR gating with a window of -0.05 ~ 3.3 ms. Shows tweeter with a strip of cardboard partially padding the 1mm gap and w/o the padding. Added the HF response from Vituix as reference, cannot sample the amp in or out signals into REW. It is higher then my 75dB reference and flatter. I already fried an audio card so I'm waiting for a replacement. In a couple of days will do more measurements as per @ctrl pointers.
To dos:
1. Replace audio card, get rid of the acrid smell that keeps reminding me to turn off stuff before moving it around
2. Get FR plots from the amp in/out
3. Close the gaps in the tweeter recess, add bottom gasket to close air leaks. Tweeter should be FLUSH with the baffle !!
4. Figure out why the IR has a long tail before the ref point. I'm guessing this might be related to the MiniDSP IR filters.
5. Run NF measurements, at least at 0deg to correlate with Directiva. And to learn how to do that
6. Long term project - get hold of x2 Purifi PRs, added bass is worth the experiment - stick them in the back (aka Sointuva) or stick them on the side (aka HIFICompass)? As I have a wall proximity issue, not sure what will be better.
And yes @Rick Sykora you're right that this sub-thread should be in a subdirectory for Directiva implementations.
This is hard fun work

 

[D!sco]

3. Close the gaps in the tweeter recess, add bottom gasket to close air leaks. Tweeter should be FLUSH with the baffle !!
This is hard fun work

Bondo is your friend for woodworking mistakes. Those gaps are worth filling, and at this price point it's worth doing correctly. It will behave similarly to MDF when finishing.
How do you plan to finish it, by the way?

 

[julbo]

Bondo is your friend for woodworking mistakes. Those gaps are worth filling, and at this price point it's worth doing correctly. It will behave similarly to MDF when finishing.
How do you plan to finish it, by the way?

Bondo is indeed a friend, I hope I don't muck that too.
I frankly didn't think of finish. I may leave them as is with stains and scratches and ... Bondo Au naturel, maybe with a varnish coating for suntan