Questioning the MiniDSP 2x4 sound quality.

[FrantzM]

I have (had, can't find it) a 2x4. It struggled to pushing voltage to my LSR308 and my subs. The 2x4 HD doesn't have this problem. Could the 2x4 non-HD distorts when pushed around 0.9V be the reason? Some gear may need a bit over 0.9 Volt... Could it be the case? Gain structure?

 

[Pdxwayne]

I have (had, can't find it) a 2x4. It struggled to pushing voltage to my LSR308 and my subs. The 2x4 HD doesn't have this problem. Could the 2x4 non-HD distorts when pushed around 0.9V be the reason? Some gear may need a bit over 0.9 Volt... Could it the case? Gain structure?

The non HD 2x4 also could not push my subs when I used it in my large living room (+5000 sq ft).

It works fine pushing my sub in my computer room, which is much smaller (~1000 sq ft). I could get satisfying bass effects in the room without having to turn my volume that loud.

So yes, I think it is gain related.

 

[mdsimon2]

Do you have a link for 4x10 measurements?

https://neurochrome.com/pages/minidsp-4x10hd

Michael

 

[Plcamp]

I found 2x4 HD noisy, but once that fixed (new power supply and clamp on ferrite beads) it was fine. I used it only on digital in, only for crossover and level/time alignment of drivers…avoiding filters except for one or two low q shelves.

I have also seen in forums that certain minidsp’s can have stability problems with low frequency filters if you are not careful.

 

[Pdxwayne]

https://neurochrome.com/pages/minidsp-4x10hd

Michael

Seems pretty nice....

Interesting that for multitones tests, he said near state of the art. I wonder if he saw all those nice DAC multitones measurements in ASR. ; )

https://cdn.shopify.com/s/files/1/0...one-IMD-32-tone-Vout-2-V-RMS.png?v=1569193060

 

[Lorenzo74]

The minidsp HD series do not measure that well....

For 2x4 HD, analog input measured even worse per Amir.

The issue is the overall sound quality based particularly on minidsp HD series. I have the 2x4 HD. Adding it to the chain added significantly louder hiss to my speakers.

Not only that... I tried it, again, a few days ago, comparing DAC to minidsp to amp, vs DAC (xlr out and not RCA out) direct to amp. I much prefer the sound quality of DAC direct to amp, even without the benefit of minidsp high pass the speaker....So, it is out of my chain again....like before....

Respectfully disagree. I have it and there is absolutely zero hiss.
Amir never said it was not ok. Read it again. I challenge you in a blind test to detect it in an HIFI gear subjectively. I mean double Blind test.
Maybe your device is broken or you pick up some noise anywhere.
Use a minidsp umik1 or Line in and software like REW and you’ll simply realize what I’m saying.
There is a very useful ABX test here in the forum where you can try to detect differences between Two musical track where one has been modified with 5%THD. Several order of magnitude higher than any Minidsp HD dac.

I recommend you to try it and see if you really can detect it. The software plug in is designed to create a blind test. You’ll get a score. Then you’ll realize how small 0.1%THD is for human ears. Hope this help.

Best
L.

 

[Pdxwayne]

Respectfully disagree. I have it and there is absolutely zero hiss.
Amir never said it was not ok. Read it again. I challenge you in a blind test to detect it in an HIFI gear subjectively. I mean double Blind test.
Maybe your device is broken or you pick up some noise anywhere.
Use a minidsp umik1 or Line in and software like REW and you’ll simply realize what I’m saying.
There is a very useful ABX test here in the forum where you can try to detect differences between Two musical track where one has been modified with 5%THD. Several order of magnitude higher than any Minidsp HD dac.

I recommend you to try it and see if you really can detect it. The software plug in is designed to create a blind test. You’ll get a score. Then you’ll realize how small 0.1%THD is for human ears. Hope this help.

Best
L.

You don't hear hiss doesn't really mean much.

My $150 speakers in my computer room don't show hiss that readily too. Doesn't mean my other $7000 Paradigm Persona B speakers won't show hiss more easily than the $150 pair of speakers.

Please save your lectures about ABX. See my own tests results link here: https://www.audiosciencereview.com/forum/index.php?threads/tracking-my-listening-tests.24364/

Try some of the online tests in my first post yourself. If you can match or beat my results, lets talk more.
: P

 

[GimeDsp]

Ok so I have had the ddrc-24 which is just the 2x4 with Dirac for about a year now and I don't like it.

I have quite a few DACs to choose from and the mini DSP is the worst. These are the the things I notice

1. Constrained sound.
Not sure if it is lack of dynamic range or what it is. But at any volume level the sound is squashed/constrained.

2. Metallic/tiny sound

3. Poor bass response

And before anyone chimes in with gain staging or room problems I have recently had a chance to set this up with well known speakers with this set up:

1. Properly placed main speakers
2. Tuned ceiling cloud
3. ASC full set up

so I know for a fact that room issues were not there as i had some of the best treatment and tuning done in my room for these tests.
MINI dsp sound sucked
Grace design balanced DAC was SO MUCH BETTER.

but that me, YMMV
I would only use the miniDSP for subwoofer stuff.

ANYONE want to buy a perfect condition DDRC-24? (maybe I shouldn't bash it if selling it)

On the flip side proper EQing and taming of peaks can bring out the actual room brightness and speaker problems so that can be some of the bad sound, but for me it is the unit that just does weird stuff.

 

[mdsimon2]

I found 2x4 HD noisy, but once that fixed (new power supply and clamp on ferrite beads) it was fine. I used it only on digital in, only for crossover and level/time alignment of drivers…avoiding filters except for one or two low q shelves.

I have also seen in forums that certain minidsp’s can have stability problems with low frequency filters if you are not careful.

The low frequency issues are common to all fixed point DSPs. Floating point DSPs like the 2X4HD do not have this issue.

Do you have any measurements documenting the noise improvement with the new power supply?

Michael

 

[Plcamp]

Do you have any measurements documenting the noise improvement with the new power supply?

No. It was audible with the supplied wall wart, I changed it to a non switching wall wart from an old ZIP drive and noise disappeared. Also had noise show up when connected to pc via USB, a ferrite clamp on USB mitigated that.

Edit: The stability problem applies when using 96k plugin and attempting to apply low frequency high pass filters…you can get severe overshoots in lf response,

 

[abdo123]

new power supply

What did you get?

 

[AldenB]

Lots of insightful replies here, thanks. I realise the hazards of the subjective listening experience (especially in this forum , so there may be other things I need to consider. The work and listening continues...

 

[raindance]

Ok. this is not in my head. I connected my Adam studio monitors directly to the DAC bypassing the minidsp and that is the sound I want! Clarity and dynamic range, albeit without my sub. Myself and anyone in the world would have no problem hearing the difference.

I don't know whats going on with this unit but it definitely lowfi. I will open it up later tonight and check the jumpers

My experience was the same. I was also told it was in my head. The cheap Dayton Audio 4X8 DSP sounds way better than the first gen mini DSP and doesn't have the signal level loss issue.

 

[Colonel7]

My experience was the same. I was also told it was in my head. The cheap Dayton Audio 4X8 DSP sounds way better than the first gen mini DSP and doesn't have the signal level loss issue.

Wish someone would send the Dayton to Amir

 

[mdsimon2]

No. It was audible with the supplied wall wart, I changed it to a non switching wall wart from an old ZIP drive and noise disappeared. Also had noise show up when connected to pc via USB, a ferrite clamp on USB mitigated that.

Edit: The stability problem applies when using 96k plugin and attempting to apply low frequency high pass filters…you can get severe overshoots in lf response,

Gotcha, was curious about the measurements as although the audio band noise level is relatively low there are two ultrasonic tones that show up in the FFT that I've wondered about. I've tried different power supplies and haven't seen any difference.

Michael

 

[mdsimon2]

Ok so I have had the ddrc-24 which is just the 2x4 with Dirac for about a year now and I don't like it.

I have quite a few DACs to choose from and the mini DSP is the worst. These are the the things I notice

1. Constrained sound.
Not sure if it is lack of dynamic range or what it is. But at any volume level the sound is squashed/constrained.

2. Metallic/tiny sound

3. Poor bass response

And before anyone chimes in with gain staging or room problems I have recently had a chance to set this up with well known speakers with this set up:

1. Properly placed main speakers
2. Tuned ceiling cloud
3. ASC full set up

so I know for a fact that room issues were not there as i had some of the best treatment and tuning done in my room for these tests.
MINI dsp sound sucked
Grace design balanced DAC was SO MUCH BETTER.

but that me, YMMV
I would only use the miniDSP for subwoofer stuff.

ANYONE want to buy a perfect condition DDRC-24? (maybe I shouldn't bash it if selling it)

On the flip side proper EQing and taming of peaks can bring out the actual room brightness and speaker problems so that can be some of the bad sound, but for me it is the unit that just does weird stuff.

Are you talking about the sound of the DAC or the sound of the Dirac correction?

You know it is possible to use another USB DAC instead of the DDRC-24 internal DAC if you use a RPi running CamillaDSP? MOTU M4 is a great option for this if you want a decently priced 4 channel balanced DAC.

Michael

 

[julesqn]

I registered just to add my voice to the chorus of "MiniDSP 2x4HD sounds noticeably bad". I can't believe how many people are trying to make it sound like you're crazy for hearing it. I've tested with several speaker/amp/dac combos, inserting it - with no processing engaged - in between the DAC's analog output (volume controlled) and the amps (or active speakers).

Issues:
1. Distortion from bass filters. There are many ways to set the bass filters such that they produce measurable and audible distortion. All of these are perfectly legal from using the MiniDSP GUI - I'm not even talking biquads imported from REW (which distort even worse). Yes, I made sure there's no clipping anywhere, and this behaviour is exhibited even with only cut filters.
2. Hiss. Very audible in this scenario (since miniDSP output is being amplified at full gain).
3. Loss of clarity / punch. Yes, this is real! It doesn't sound outright "bad" - just "worse than without it". To me, that makes it unusable. This is less of an issue when you use the MiniDSP digital inputs, but its still bad.

It's a hard scenario to get right because MiniDSP converters are dealing with really low input and output signals, and full-scale amplification of the unit's hiss. But this is the exact scenario that the MiniDSP is designed for! We aren't going to use a 4-channel analog volume control after the MiniDSP to trim down the hiss level and allow higher input and output...

So, although it offers fantastic flexibility for integrating subs, or a 2 way crossover with correction, the degredation in quality eventually gets to me and the MiniDSP returns to the drawer, to be replaced by an analog crossover (plus software room correction).

 

[Pdxwayne]

I registered just to add my voice to the chorus of "MiniDSP 2x4HD sounds noticeably bad". I can't believe how many people are trying to make it sound like you're crazy for hearing it. I've tested with several speaker/amp/dac combos, inserting it - with no processing engaged - in between the DAC's analog output (volume controlled) and the amps (or active speakers).

Issues:
1. Distortion from bass filters. There are many ways to set the bass filters such that they produce measurable and audible distortion. All of these are perfectly legal from using the MiniDSP GUI - I'm not even talking biquads imported from REW (which distort even worse). Yes, I made sure there's no clipping anywhere, and this behaviour is exhibited even with only cut filters.
2. Hiss. Very audible in this scenario (since miniDSP output is being amplified at full gain).
3. Loss of clarity / punch. Yes, this is real! It doesn't sound outright "bad" - just "worse than without it". To me, that makes it unusable. This is less of an issue when you use the MiniDSP digital inputs, but its still bad.

It's a hard scenario to get right because MiniDSP converters are dealing with really low input and output signals, and full-scale amplification of the unit's hiss. But this is the exact scenario that the MiniDSP is designed for! We aren't going to use a 4-channel analog volume control after the MiniDSP to trim down the hiss level and allow higher input and output...

So, although it offers fantastic flexibility for integrating subs, or a 2 way crossover with correction, the degredation in quality eventually gets to me and the MiniDSP returns to the drawer, to be replaced by an analog crossover (plus software room correction).

Which analog crossover are you using?

Thanks!

 

[Doodski]

If I can pop in here @Pdxwayne I used one of these Coustic XM-7 crossovers for my home tri-amp'd system. It worked fabulously. I took a 13.4VDC 120VACsupply and swapped out the smoothing capacitance for something significantly larger and voila a home unit that had little to no hiss and was inexpensive.

 

[Pdxwayne]

If I can pop in here @Pdxwayne I used one of these Coustic XM-7 crossovers for my home tri-amp'd system. It worked fabulously. I took a 13.4VDC 120VACsupply and swapped out the smoothing capacitance for something significantly larger and voila a home unit that had little to no hiss and was inexpensive.

Interesting, using mobile crossover. Thanks for the idea.