Minidsp Flex Review (Audio DSP)

[mdsimon2]

I am looking into a Flex or SHD Studio for my system and I am considering it as a DIRAC platform/input switcher with a secondary DSP (CamillaDSP on an Rpi) for the actual crossover work. My questions are:

Does it work (well enough) to use DIRAC on one system and another for the PEQ, FIR filters, Xover, etc.? Or is it too much of a faff in actual use? I am thinking about this signal path:

Flex as source > DIRAC applied > AES/EBU out > in Okto Dac8Pro > out over USB to CamillaDSP RPi > in over USB back to Okto > Okto analog out to amps

I did this exact setup with a SHD Studio and an Okto for a while. Eventually I stopped using Dirac as I didn't find it was necessary with CamillaDSP. IMO it is a good setup if you are starting from a documented active design (like the Linkwitz designs) and want add Dirac to it.

I believe, but please get it confirmed by someone else, that you can do it a bit simpler with the same devices:
Flex with Dirac as source > USB > rpi with camilladsp > USB > DAC
I am doing something similar with a minidsp 2x4 hd, but I think it works the same with the flex

There are pros and cons for using AES vs USB from the Flex.

AES avoid resampling and rate adjust as the Okto will be clocked via the AES input. Downside to this is you can only run the Okto at the sample rate of the Flex (48 kHz for Dirac, 96 kHz for no Dirac)

USB requires asynchronous resampling and rate adjust to bridge the clock domains but you can run the Okto at any sample rate you want (input data will still be 48/96 kHz). The big disadvantage here is you lose the USB input of the Flex because it is tied up by the RPi.

Overall I think AES is the better way to go but YMMV.

Michael

 

[gandalfandula]

I believe, but please get it confirmed by someone else, that you can do it a bit simpler with the same devices:
Flex with Dirac as source > USB > rpi with camilladsp > USB > DAC
I am doing something similar with a minidsp 2x4 hd, but I think it works the same with the flex

Good point, I wouldn't need to go in and out of the DAC separately. Is there any issue with running DIRAC on a separate device? Do you have any sample rate issues between devices?

You might want to consider a PC which has considerably more power than any MiniDSP. You could do all your crossovers and room EQ with DIRAC with the PC and just out to Okto DAC and you are done. Not to mention PC is great as a source, and storage, and much more.

I have considered it. I wanted to avoid going to a PC based system since I am trying to separate the computer paradigm from the listening area paradigm, for no other reason than that of user interface. I want my wife to be able to operate the input switching and volume (e.g. Roon/streaming vs TV audio, etc.), and it's also just easier for me too if it's based around something like the Flex units that have a nice screen and a normal remote. Of course the DSP functions are less user friendly, but those don't need to be adjusted very often. The minidsp units are also handy in that they have presets, but I am skeptical if they have the processing power to do a full FIR implementation on board, hence the interest in CamillaDSP (and the helpful insights from mdsimon2!).

 

[MCH]

AES avoid resampling and rate adjust as the Okto will be clocked via the AES input. Downside to this is you can only run the Okto at the sample rate of the Flex (48 kHz for Dirac, 96 kHz for no Dirac)

Well, another "disadvantage" of the aes/ebu is that he would necessarily need to go for the studio...
Edit: well, having the okto, who cares.

 

[mdsimon2]

Well, another "disadvantage" of the aes/ebu is that he would necessarily need to go for the studio...
Edit: well, having the okto, who cares.

Okto will accept SPDIF with a simple RCA to XLR cable. Can also use a transformer if you want but I have found it isn't needed.

Michael

 

[will.b]

I am looking into a Flex or SHD Studio for my system and I am considering it as a DIRAC platform/input switcher with a secondary DSP (CamillaDSP on an Rpi) for the actual crossover work. My questions are:

Does it work (well enough) to use DIRAC on one system and another for the PEQ, FIR filters, Xover, etc.? Or is it too much of a faff in actual use? I am thinking about this signal path:

Flex as source > DIRAC applied > AES/EBU out > in Okto Dac8Pro > out over USB to CamillaDSP RPi > in over USB back to Okto > Okto analog out to amps

What about just using the Flex Eight?

miniDSP Flex Eight

miniDSP Flex Eight, 400MHz Sharc DSP audio processor, toolbox for subwoofer or multiway speaker tuning, Optional Dirac Live license for room correction, Bluetooth LDAC/APTX/AAC streaming.

www.minidsp.com

 

[MCH]

Good point, I wouldn't need to go in and out of the DAC separately. Is there any issue with running DIRAC on a separate device? Do you have any sample rate issues between devices?

Sorry I missed your question. No issues at all with sample rates, works incredibly well. See here:
Post in thread 'RPi4 + CamillaDSP Tutorial' https://audiosciencereview.com/forum/index.php?threads/rpi4-camilladsp-tutorial.29656/post-1284938

 

[Marc v E]

What about just using the Flex Eight?

miniDSP Flex Eight

miniDSP Flex Eight, 400MHz Sharc DSP audio processor, toolbox for subwoofer or multiway speaker tuning, Optional Dirac Live license for room correction, Bluetooth LDAC/APTX/AAC streaming.

www.minidsp.com

Good suggestion! This seems like everything you would need, @gandalfandula. All in one device: Dsp, dac, crossovers, Dirac. Pls correct me if I'm wrong.

 

[aikofan]

Has anyone else had problems with the Device Console upgrade? After updating my software, my PC no longer recognizes my Flex and I no longer have music. I had to submit a support request.

 

[will.b]

Has anyone else had problems with the Device Console upgrade? After updating my software, my PC no longer recognizes my Flex and I no longer have music. I had to submit a support request.

It's working fine for me.
I just followed the instuction notes. Had a few reboots and resync from what I remember.

Maybe try to completly remove the drivers/software and start again with just the new version.

 

[poxymoron]

It's working fine for me.
I just followed the instuction notes. Had a few reboots and resync from what I remember.
View attachment 238944

Maybe try to completly remove the drivers/software and start again with just the new version.

Same for me, it just worked. A lot less hassle in fact than when I setup my Flex originally.

 

[will.b]

Same for, it just worked. A lot less hassle in fact than when I setup m my Flex originally.

Nice option on there now to "CUSTOMIZE SELECTION" where you can just select the inputs you use.
For me it's just USB for the PC and TOSLINK for the TV, so now when I use the remote to switch input, it only has the two choices to alternate.

 

[poxymoron]

Nice option on there now to "CUSTOMIZE SELECTION" where you can just select the inputs you use.
For me it's just USB for the PC and TOSLINK for the TV, so now when I use the remote to switch input, it only has the two choices to alternate.

Didn't spot that, thanks.

 

[ELberto]

Has anyone else had problems with the Device Console upgrade? After updating my software, my PC no longer recognizes my Flex and I no longer have music. I had to submit a support request.

Yes. Bricked my Flex. Returned it and moved on.

 

[aikofan]

Yes. Bricked my Flex. Returned it and moved on.

Man, that’s rough. After several reboots, my Flex is now recognized by my PC, but the updated driver doesn’t play any sounds, neither through the Windows sound device test tones, LMS, or Foobar2000. I’ll see what miniDSP support has to say. Aside from not playing any sounds, the Device Console seems to have a much better UI than the previous software, so I hope I’m not forced to restore the old set up all over again.

 

[gandalfandula]

Okto will accept SPDIF with a simple RCA to XLR cable. Can also use a transformer if you want but I have found it isn't needed.

Michael

So just a "normal" one - you weren't using 110 ohm cables or something like that?

 

[mdsimon2]

Just standard cables, these to be exact -> https://www.monoprice.com/product?p_id=4777.

If you want to be extra careful you could use a RCA to BNC cable like this -> https://www.bhphotovideo.com/c/product/1053962-REG/kopul_vrbc_406_bnc_male_to_rca.html in to a 75 ohm to 110 ohm transformer like this -> https://www.bhphotovideo.com/c/product/367655-REG/Canare_BCJXPTRB_BCJ_XP_TRB_75_Ohm_to.html but I don't think it is worth it unless you have obvious issues with a standard RCA to XLR cable.

Michael

 

[onlyoneme]

I've tried to compare WiiM's toslink output to the source file and I've got very bad results on Flex. I had RME bitperfect test file 24/96. When recorded over ASIO during playback on USB I got this:

But when playing from WiiM using its toslink I got this:

All above are waveforms in ocenaudio, recorded of Flex with ASIO driver.

I'm not sure if it's a WiiM issue, or my Flex is affected. Could someone make similar test with toslink in Flex?

 

[mdsimon2]

I've tried to compare WiiM's toslink output to the source file and I've got very bad results on Flex. I had RME bitperfect test file 24/96. When recorded over ASIO during playback on USB I got this:
View attachment 239140
View attachment 239141

But when playing from WiiM using its toslink I got this:
View attachment 239142

View attachment 239143
All above are waveforms in ocenaudio, recorded of Flex with ASIO driver.

I'm not sure if it's a WiiM issue, or my Flex is affected. Could someone make similar test with toslink in Flex?

I don't know the specifics behind your test but the output of the Flex will not be bit perfect as it goes through an ASRC.

Michael

 

[onlyoneme]

I don't know the specifics behind your test but the output of the Flex will not be bit perfect as it goes through an ASRC.

Michael

I know that, but I was expecting the same results over toslink and over usb with the same test file. And I've got different results.

 

[onlyoneme]

Regarding my issues above - it looks like the WiiM's problem and not miniDSP Flex one. Current WiiM FW seems to be no longer bitperfect as it introduces high level of distortions to the sound.