Minidsp Flex Review (Audio DSP)

[testp]

Can't you just choose the sample rate in settings?

View attachment 208898
from the manual

minidps does convert everything to 96khz before dsp, if what you are showing is after dsp, then this could be the solution

 

[deafenears]

a wobbly decoder button that is almost scary to use,

For those following, I managed to replace the knob. It takes 5mm:

 

[TheBatsEar]

interesting... i can get past the lights and the fiddly dial, but if it does not work well as a "close enough" state of the art USB DAC it is of no interest to me. Are you underwhelmed by the sound?

He has the digital version and didn't use it as a DAC.
I have the RCA output version and use it as a USB DAC and it makes no difference to me compared to a Topping E30 or Yamaha A-S801.

As for up/down sampling being audible ... i have doubts.
I can tell Moode to send whatever i think is best, in this case 24bit/96kHz, and i can choose different scaling precision algorithms (that use up different amounts of CPU). None of them made a difference to me either.

Tin ears, right?

 

[as labs]

He has the digital version and didn't use it as a DAC.
I have the RCA output version and use it as a USB DAC and it makes no difference to me compared to a Topping E30 or Yamaha A-S801.

As for up/down sampling being audible ... i have doubts.
I can tell Moode to send whatever i think is best, in this case 24bit/96kHz, and i can choose different scaling precision algorithms (that use up different amounts of CPU). None of them made a difference to me either.

Tin ears, right?

what does tin ears mean - like opposite of golden?

would you agree the DAC quality compares roughly to mid range consumer DAC's? seems to me this is what you are saying.

does anyone have experience or comparison with mid-range pro DSP units like models from harman/BSS, xilica, symetrix, dbx?

i have a minidsp 2x4HD - does anyone have direct comparison with the HD and the flex?
i wish they allowed returns... i guess i'm being cheap. i have unfortunately developed expensive taste from work tuning studio systems. it's like working at a fancy wine bar and then going home to two-buck chuck...

 

[antcollinet]

what does tin ears mean - like opposite of golden?

would you agree the DAC quality compares roughly to mid range consumer DAC's? seems to me this is what you are saying.

does anyone have experience or comparison with mid-range pro DSP units like models from harman/BSS, xilica, symetrix, dbx?

i have a minidsp 2x4HD - does anyone have direct comparison with the HD and the flex?
i wish they allowed returns... i guess i'm being cheap. i have unfortunately developed expensive taste from work tuning studio systems. it's like working at a fancy wine bar and then going home to two-buck chuck...

The reviews are here:

Review and Measurements and miniDSP 2x4 HD DSP and DAC

This is a brief review and measurements of miniDSP 2x4 HD Processor and USB DAC. I purchased this online and seems like the price as of this writing is USD $207 as of this writing. This is a USB DAC with Toslink optical input and analog/digital in, four channel digital signal processor (DSP)...

www.audiosciencereview.com

and here:

Minidsp Flex Review (Audio DSP)

This is a review and detailed measurement of the Minidsp Flex audio signal processor. It was sent to me by the company and costs US $475 for unbalanced and $550 for balanced that I tested. Flex borrows the interface from SHD and puts it in a compact package. Seeing how I really liked that...

www.audiosciencereview.com

Unfortunately a long time apart, and the measurement process has changed. However the flex is around 20dB better on both noise and distortion. That is significant.

The Flex ranks quite highly on Sinad compared to the best DACs, as you can see in the chart in the review - more than halfway along the blue section. You won't hear the difference between the flex and those at the top of the chart. Noise and distortion are already below the level of audibility.

 

[TheBatsEar]

what does tin ears mean - like opposite of golden?

Yes

would you agree the DAC quality compares roughly to mid range consumer DAC's? seems to me this is what you are saying.

Yes

i have a minidsp 2x4HD - does anyone have direct comparison with the HD and the flex?

I have both. The Flex is basically a 2x4HD in DSP functionality, but measures better. Both are measured by Amir somewhere on this site, you can compare them directly.

If you ask me if you should upgrade, the answer is no, likely your gains are better by getting better speakers and room treatment instead of wasting money on DACs and DSPs. Best to start a thread for it, describe what you have, what you think you should do and ask what others think.

 

[MCH]

The Flex ranks quite highly on Sinad compared to the best DACs, as you can see in the chart in the review - more than halfway along the blue section. You won't hear the difference between the flex and those at the top of the chart. Noise and distortion are already below the level of audibility.

Tony, what is yout take on the imd of the flex when talking about low sinad and comparing to the sota dacs?
After almost 1000 posts this is yet to be discussed, or is it that completely irrelevant? If i look at the graph, imd starts picking up quite early

 

[antcollinet]

Tony, what is yout take on the imd of the flex when talking about low sinad and comparing to the sota dacs?
After almost 1000 posts this is yet to be discussed, or is it that completely irrelevant? If i look at the graph, imd starts picking up quite early

Yes - IMD is its weakest point.

Even on the multitone test though, it is still down at -90+dB (0.003%), and that is with high frequency tones at a *very* much higher level than you get in music. I'm not worried about it being audible.

An exercise for the reader is to see where a ranking of IMD would put it on a chart compared with other DACs

 

[MCH]

Yes - IMD is its weakest point.

Even on the multitone test though, it is still down at -90+dB (0.003%), and that is with high frequency tones at a *very* much higher level than you get in music. I'm not worried about it being audible.

An exercise for the reader is to see where a ranking of IMD would put it on a chart compared with other DACs

I trust you, just calls my attention that doesn't seem to be able to clear even the 16bits mark of "clean signal under any circumstances".

Regarding the ranking.... i am afraid it would do pretty bad.

 

[TheBatsEar]

I trust you, just calls my attention that doesn't seem to be able to clear even the 16bits mark of "clean signal under any circumstances".

Perfect for MQA then.

But just so we know what we are talking about, this, in my humble opinion, is good enough. Real music will never look as bad like this synthetic benchmark:

 

[MCH]

Well, i was looking at the imd graph, just above the multitone, that seems to indicate a floor of ca 90db starting at -20db signal (i tend to think that you get the best of your dac with low attenuation, but -20db seem quite reachable even if you use the flex as preamp). I don't really understand how this translates to real life: what are the chances we have more that one frequency reaching high levels and what are the consequences if that happens, that's why i was asking.

 

[TheBatsEar]

Well, i was looking at the imd graph, just above the multitone, that seems to indicate a floor of ca 90db starting at -20db signal (i tend to think that you get the best of your dac with low attenuation, but -20db seem quite reachable even if you use the flex as preamp). I don't really understand how this translates to real life: what are the chances we have more that one frequency reaching high levels and what are the consequences if that happens, that's why i was asking.

I think it means distortion is at least 90dB from the signal at all times.

If your background noise is 45dB (i have more because city environment), you would need to play music at more than 135dB to have it in the signal. At which time your speakers would melt and your inner ears would start bleeding of course. Not to mention that you will not hear any distortion from your source if you play signal at 135dB+.

That is how i interpret it.

 

[MCH]

Yes, sure, fully agree, 90 db is more than plenty, no doubt about it, and this brings us to the eternal discussion of how much is enough and all that.... i just feel in this particular case imd might be worth to mention when comparing the flex with other sota dacs. It might be one of this cases that a single 1kHz tone does not tell all the story.

 

[HarmonicTHD]

Yes, sure, fully agree, 90 db is more than plenty, no doubt about it, and this brings us to the eternal discussion of how much is enough and all that.... i just feel in this particular case imd might be worth to mention when comparing the flex with other sota dacs. It might be one of this cases that a single 1kHz tone does not tell all the story.

It is as BatEar said regardless if 1kHZ, IMD or any other test signal if SignalSPL minus distortion/noise/imd is below room noise or even to be more conservative below 0dBSPL you don’t hear it.

see also here

Audibility thresholds of amp and DAC measurements

Introduction A recurring theme on ASR is whether or not the various measured qualities of the devices are audible. In this post, I'll present some clear and visual thresholds for when those imperfections can be considered a potentially audible concern. I will not explain the basics of amp/DAC...

www.audiosciencereview.com

or here

Interpreting THD Measurements - Think dB not Percent!

Distortion measurements (THD, THD+N and IMD) are traditionally expressed in terms of percent. But what do 1%, 0.1%, 0.01% or 0.001% mean in terms of loudness or audibility? If you are like most people you just know that 0.001% is the best of the three numbers listed above. If you are a...

benchmarkmedia.com

or if still in doubt, ABX test for yourself. There are some software tools in this forum. It is mainly sobering in terms what you thought you can hear and what you actually do in ABX.

 

[usersky]

Lovely little device but there is something that really needs to be addressed with a firmware update: acceleration for the volume. It really seems out of control.

 

[as labs]

I think it means distortion is at least 90dB from the signal at all times.

If your background noise is 45dB (i have more because city environment), you would need to play music at more than 135dB to have it in the signal. At which time your speakers would melt and your inner ears would start bleeding of course. Not to mention that you will not hear any distortion from your source if you play signal at 135dB+.

That is how i interpret it.

A bit of a tangent here, but not exactly. impulsive sounds like music are audible at 10dB+ below the ambient sound level. I'm no expert for audibility in IMD, so i won't comment there.

also background sound level in most homes is level dependent - far higher at low frequencies than high, which is where i'd expect we would detect distortion issues. I work in acoustics and a quiet urban residence is typically 30 dBA, with something like 50-60 dB in 63 hz octave band and sometimes 10-20 dB in 1k-4kHz.

ok, all finished derailing the conversation

 

[as labs]

Perfect for MQA then.

But just so we know what we are talking about, this, in my humble opinion, is good enough. Real music will never look as bad like this synthetic benchmark:
View attachment 209203

I guess i don't understand what this result means in the real world. this does look quite bad compared to other usb DAC's.
From what I can ascertain from the measurement results for the flex:

1. 1kHz tone yields good results when compared with other DACs.
2. Multitone does not rank as well (thanks for posting the plot)
3. IMD is frequency dependent (i think, right?)

which frequencies are offending? i suspect high frequencies, but i have no idea.

 

[tjcinnamon]

If I have 2 of these could I run Dirac on my LCR-Sub and have them all correlate? Or does Dirac only do one device at a time where I’d need a 4 input Flex

 

[antcollinet]

I trust you, just calls my attention that doesn't seem to be able to clear even the 16bits mark of "clean signal under any circumstances".

Regarding the ranking.... i am afraid it would do pretty bad.

Armin’’s multitone test specifically states it does have 16 bits Of distortion free range.

 

[Sluraad]

If I have 2 of these could I run Dirac on my LCR-Sub and have them all correlate? Or does Dirac only do one device at a time where I’d need a 4 input Flex

You would be calibrating them separately but it is possible. You could do some work in REW afterwards to get the levels balanced.