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Minidsp Flex Review (Audio DSP)

Rate this product:

  • 1. Poor (headless panther)

    Votes: 2 0.5%
  • 2. Not terrible (postman panther)

    Votes: 8 2.0%
  • 3. Fine (happy panther)

    Votes: 86 21.2%
  • 4. Great (golfing panther)

    Votes: 309 76.3%

  • Total voters
    405

tonycollinet

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Check out this Audioholics review of what happened when they changed the crossover of a high end speaker to one using phase coherent FIR filters. Gene Dellasalla, the head of Audioholics, said he was skeptical that phase coherence based on papers he had read, but after listening to the difference as they switched back and forth he called FIR filters a "game changer", achieving "immediacy to the sound", "better imaging", and the "utmost accuracy and lifelike sound".

Ignore my opinion, watch the Audioholics 11:57 minute review here.

Do you think Gene Dellasalla was imagining things?

They used an expensive professional processor by Marani to do the FIR crossover filters, but the miniDSP Flex can do the same thing.
Did he test blind or sighted. If sighted he may well have been subject to confirmation bias, expectation bias etc.

No-one is immune - it is how our brains work.
 

Dan B

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Those impressions are worthless unless backed up by double-blind testing and his resulting confidence score. Yeah placebo is a real killjoy.
Perhaps it's just not worth checking out without a structured, certified double-blind test that you can participate in, which may never happen. Just ignore it.
 

Dan B

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Did he test blind or sighted. If sighted he may well have been subject to confirmation bias, expectation bias etc.

No-one is immune - it is how our brains work.
Do you insist on a certified double blind test whenever you listen to new audio equipment? Is there any point in listening and evaluating any new audio equipment, say at a high end audio store, without a certified double blind test?
 

dublinthedog777

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Just got the balanced version and can not sum my L and R channels for the subwoofer, and appears to be some kind of phase error as stereo image is no longer there and voices seem to coming from two directions until I invert one of the speakers. Old dac sounds perfectly fine. No returns, made in China. My mistake.
 

levimax

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Do you insist on a certified double blind test whenever you listen to new audio equipment? Is there any point in listening and evaluating any new audio equipment, say at a high end audio store, without a certified double blind test?
The problem is unless the equipment you are comparing is level matched and blind it is not a useful test.
 

tonycollinet

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Do you insist on a certified double blind test whenever you listen to new audio equipment? Is there any point in listening and evaluating any new audio equipment, say at a high end audio store, without a certified double blind test?
When I'm listening to music, I'm not trying to make a definitive claim that a particular characteristic of that music is audible. Or not. I'm just enjoying music.

If I'm evaluating new kit, I'll short list that kit based on measurements. If I listen to kit (particularly electronics), it'll only be to ensure there is nothing fundamentally broken about the way it performs in my room/environment. I'll not be expecting to hear significant differences with what I have now, except where measurements tell me I might (eg power). Speakers a slightly different issue. But again I'll be listening for something not working in my room, that doesn't gel with the measurements.

Most importantly - if I'm evaluating new kit I'm only doing it for *me*. I'm not going to try to convince others that what I (think) I hear is correct. That they should buy the same kit because I think it sounds great.

On the other hand.

If I'm trying to provide evidence that Phase shift is audible I can't do it with sighted listening tests because everyone with any knowledge of psychoacoustics knows that my (like everyone else's) ear/brain is subject to unconcious bias. We can only prove a difference can be heard by doing it blind and controlled.

Especially when all the other published information doesn't point towards audibility. In that case I am making a claim that requires a high level of support (evidence)
 

tonycollinet

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Just got the balanced version and can not sum my L and R channels for the subwoofer, and appears to be some kind of phase error as stereo image is no longer there and voices seem to coming from two directions until I invert one of the speakers. Old dac sounds perfectly fine. No returns, made in China. My mistake.
How are you trying to sum your channels? What happens when you try?

If you need to invert one of your speakers, I'd be suspicious of your cables before the flex. Or of your configuration/filters. Have you tried with all filters removed? (Factory config)
 

dublinthedog777

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How are you trying to sum your channels? What happens when you try?

If you need to invert one of your speakers, I'd be suspicious of your cables before the flex. Or of your configuration/filters. Have you tried with all filters removed? (Factory config)
I am doing it as stated in the manual, output three sending left and right channels. Sound outputs when I am just sending the L or R channel then goes silent when they are combined(visually stops sending info on the EQ bars as well). I have had an SHD in this system and it worked fine, I am familiar with the software and have reset to factory several times.
 

withoutsuit

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Today I tried to replace my DDRC-24 with the Flex Digital. Unfortunately, the RCA Outputs of the old DDRC are fully dedicated assignable whereas the digital outputs of the Flex only work as a pair (1 toslink + 2 coax and 3 toslink + 4 coax carry the same signal). What a pitty - It's now useless for me :( Just to warn others, who think it's flexible as the DDRC but fully digital...
 
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mdsimon2

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Today I tried to replace my DDRC-24 with the Flex Digital. Unfortunately, the RCA Outputs of the old DDRC are fully dedicated assignable whereas the digital outputs of the Flex only work as a pair (1 toslink + 2 coax and 3 toslink + 4 coax carry the same signal). What a pitty - It's now useless for me :( Just to warn others, who think it's flexible as the DDRC but fully digital...

I mean...obviously, it doesn't have 8 output channels. How is it not as flexible as the DDRC? What did you expect to be able to do that you cannot?

Michael
 

withoutsuit

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I mean...obviously, it doesn't have 8 output channels. How is it not as flexible as the DDRC? What did you expect to be able to do that you cannot?

Michael
Well, just what I wrote. e.g. If you want to use 2 Toslink and 1 Coax output with independent delay, its not possible, because 1 toslink and 1 coax are always a pair. The DDRC can handle it. After trying for hours, I read that in the manual. Should be more clear at the product page. Maybe / I think the RCA Version can do this.
 

mdsimon2

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Well, just what I wrote. e.g. If you want to use 2 Toslink and 1 Coax output with independent delay, its not possible, because 1 toslink and 1 coax are always a pair. The DDRC can handle it.

Again it doesn't have 8 output channels, just like the DDRC. You can output 4 channels and do whatever independent processing on those 4 channels you want, just like the DDRC.

Your example would imply the use of 6 outlet channels (2 x TOSLINK = 4 channels, 1 x Coax = 2 channels).

I am not sure where the confusion lies. What are you specifically trying to do?

Michael
 

deafenears

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Well, just what I wrote. e.g. If you want to use 2 Toslink and 1 Coax output with independent delay, its not possible, because 1 toslink and 1 coax are always a pair. The DDRC can handle it. After trying for hours, I read that in the manual. Should be more clear at the product page. Maybe / I think the RCA Version can do this.
Again it doesn't have 8 output channels, just like the DDRC. You can output 4 channels and do whatever independent processing on those 4 channels you want, just like the DDRC.
@withoutsuit , like what @mdsimon2 says above, the Flex only has 4 output channels. Each pair are output via both via the optical TOSLINK and coax.

So channels/output 1 & 2 via TOSLINK *and* coax on the left under the label "1& 2". Channels/output 3 & 4 via both TOSLINK and coax on the right under label "3& 4".
 

deafenears

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Anyone know if the volume knob is replaceable ? Looking to replace it with something deeper, it doesn't seem to come off easy and I don't want to use force in case it breaks it.
 

Blew

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The MininDSP Flex looks like a good unit for a 2.2 setup, but I wonder how it compares to processing DSP in software before outputting via a stereo DAC then adjusting the crossover on the amplifier.

Is there a measurable advantage to processing DSP in a hardware unit like the Flex before outputting the separate channels individually to 2x active subwoofers + stereo amplifier?

For example:
Streamer/CD player -> MiniDSP Flex DSP, individual channel outputs (stereo amplifier -> passive speakers, subwoofer RCA -> active subwoofers)
vs
Pi4/CamillaDSP, Roon, Volumio etc streamer + DSP -> stereo DAC -> multichannel amplifier with bass crossover -> active subwoofers & passive speakers

Has anyone done any measurements to compare these configurations?
 

Sluraad

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I am doing it as stated in the manual, output three sending left and right channels. Sound outputs when I am just sending the L or R channel then goes silent when they are combined(visually stops sending info on the EQ bars as well). I have had an SHD in this system and it worked fine, I am familiar with the software and have reset to factory several times.
I inverted my subwoofer with my balanced Flex, which sounds like what you need as well, I was getting inconsistent FR readings when playing crossover content. I've tried looking into it more but I'm not sure why, maybe it has something to do with a TRS adapter -> RCA cable into a sub?
I've got one of the official miniDSP cables on order, I'll have to see if that returns it to normal.
 

tonycollinet

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The MininDSP Flex looks like a good unit for a 2.2 setup, but I wonder how it compares to processing DSP in software before outputting via a stereo DAC then adjusting the crossover on the amplifier.

Is there a measurable advantage to processing DSP in a hardware unit like the Flex before outputting the separate channels individually to 2x active subwoofers + stereo amplifier?

For example:
Streamer/CD player -> MiniDSP Flex DSP, individual channel outputs (stereo amplifier -> passive speakers, subwoofer RCA -> active subwoofers)
vs
Pi4/CamillaDSP, Roon, Volumio etc streamer + DSP -> stereo DAC -> multichannel amplifier with bass crossover -> active subwoofers & passive speakers

Has anyone done any measurements to compare these configurations?
Any difference will likely come from two areas.

1 - Capabilities of the DSP software, eg Camilla vs Dirac (or REW/Parametric EQ if that is what you are using)

2 - Crossover capablity - Frequency response, filter rolloff, delays/phase etc in the Flex Vs Amp.

In other words - the hardware is just a vehicle for whatever DSP you are running. It is the software that will determine the effectiveness of the result. (within limits - eg sampling rate capability/number of parallel filters etc).
 

Dan B

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When I'm listening to music, I'm not trying to make a definitive claim that a particular characteristic of that music is audible. Or not. I'm just enjoying music.

If I'm evaluating new kit, I'll short list that kit based on measurements. If I listen to kit (particularly electronics), it'll only be to ensure there is nothing fundamentally broken about the way it performs in my room/environment. I'll not be expecting to hear significant differences with what I have now, except where measurements tell me I might (eg power). Speakers a slightly different issue. But again I'll be listening for something not working in my room, that doesn't gel with the measurements.

Most importantly - if I'm evaluating new kit I'm only doing it for *me*. I'm not going to try to convince others that what I (think) I hear is correct. That they should buy the same kit because I think it sounds great.

On the other hand.
If I'm trying to provide evidence that Phase shift is audible I can't do it with sighted listening tests because everyone with any knowledge of psychoacoustics knows that my (like everyone else's) ear/brain is subject to unconcious bias. We can only prove a difference can be heard by doing it blind and controlled.

Especially when all the other published information doesn't point towards audibility. In that case I am making a claim that requires a high level of support (evidence)
 

abdo123

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Check out this Audioholics review of what happened when they changed the crossover of a high end speaker to one using phase coherent FIR filters. Gene Dellasalla, the head of Audioholics, said he was skeptical that phase coherence based on papers he had read, but after listening to the difference as they switched back and forth he called FIR filters a "game changer", achieving "immediacy to the sound", "better imaging", and the "utmost accuracy and lifelike sound".

Ignore my opinion, watch the Audioholics 11:57 minute review here.

Do you think Gene Dellasalla was imagining things?

They used an expensive professional processor by Marani to do the FIR crossover filters, but the miniDSP Flex can do the same thing.
For me linearising the phase of my crossovers did sound different, but not different enough for me to appreciate one over the other.
 

abdo123

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Do you insist on a certified double blind test whenever you listen to new audio equipment? Is there any point in listening and evaluating any new audio equipment, say at a high end audio store, without a certified double blind test?
You can evaluate audio equipment without blind listening, but you can’t compare them to each other without it.
 
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