Article: Grimm Audio MU1 Music Player Review

[The Computer Audiophile]

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[The Computer Audiophile]

5 minutes ago, FredM said:

“ The Grimm Audio MU1 digital music source is absolutely the right product for many listeners in our wonderful hobby. If perusing the MU1 thread here on Audiophile Style is any indication, most people set it and forget it, at either 2fs or 4fs oversampling. The concept and validity of an external up/oversampling device has long been proven highly effective in many audio systems. The MU1 takes this a step further by including a Roon core and an advanced FPGA working to extend the capabilities of Roon, to deliver a pristine audio signal out to a DAC. “
 

Imho spot on 👍. It’s an one box solution that offers turn key musical enjoyment. End game for many. Personally one of my best ever hifi choices, it just keeps amazing me.
 

Thanks for sharing your experience Chris, a well written review with nice new insights which were untouched in the other MU1 reviews. I can imagine that (heavy) thinkering/tweaking curiosity (experimenting with oversampling, DAC filters or DSP and Convolution settings, I didn't knew what it is 😀) require some determination given the bunch of combinations. Thanks!
 

Thanks so much @FredM. I'm very grateful your MU1 thread in the forum has provide so much information. Seeing how everyone uses the MU1 and the success they've had is really nice. 

 

Question: Do you use internal storage?

[The Computer Audiophile]

1 hour ago, Richh84 said:

Any update from grimm on why the roon convolution w/ grimm upsampling issue?

I can only speak for myself on this one. With so many variables, it's probably best to know about my issue using convolution with the MU1's oversampling, but not think much more about it. All convolution filters are different, convolution engines are different, DACs are different, etc... My issue could be a non-issue for everyone else. I really wish others with the MU1 used convolution and could give me some feedback on how it sounds in their system with oversampling set to No/2fs/4fs. 

[The Computer Audiophile]

1 hour ago, 57gold said:

So exactly what does this $10.5K box do that say a $2.5K Mac Studio with 2TB of SSD and Roon software can't do?

 

Alternatively, I'm guessing that with say HQ Player on the Mac Studio, it can do things that the Grimm unit cannot.

 

Looks nicely made.

Like everything, it isn’t for everyone. The built-in DSP is “idiot” proof, with a couple radio buttons to click. There is nothing to update when a new OS comes out or OS settings to adjust etc… plus, the Grimm DSP is proprietary, and something not available elsewhere. 
 

That said, if you have a Mac and HQP, and a DAC that accepts the stream coming from that, you can do incredible things. The learning curve can be steep though. 
 

I’m glad we have options. 

[The Computer Audiophile]

5 hours ago, 57gold said:

Thanks pmorali for sharing your experience with this product.

 

Still not sure I understand its functions / capabilities.  The company's website seems to indicate that it is a DAC (Do you use it as a DAC? Review has it hooked up to super DACs.), has limited built in upsampling capabilities, there is no info on its capabilities with respect to player software like HQPlayer and dealing with upconverting to DSD 128 or higher using its powerful filters.  

No DAC in MU1. Word on the street is the MU2 will contain a DAC. 

[The Computer Audiophile]

5 minutes ago, Flashman said:

Two thoughts:

1) A friend of mine says that the Tambaqui DAC with the Grimm MU1 is the best digital system he's ever heard.

2) For a few years, Grimm has been touting an upcoming MU2, which would add a DAC.  As it's been some time, I suspect the Grimm folks are having some issues.  Did you hear anything about a MU2?

Here is info about the MU2, straight from Eelco Grimm. 
 

https://audiophilestyle.com/forums/topic/58754-grimm-audio-mu1-server/?do=findComment&comment=1215325

 

[The Computer Audiophile]

9 minutes ago, soupcon said:

Appreciate this review. The MU1 is the most consequential audio expenditure in a long time. I spend a lot more time enjoying music than I have in a long time. 

 

 

Great to hear @soupcon

[The Computer Audiophile]

8 hours ago, FredM said:

After testing various settings in and outside the MU1, you mentioned that you preferred the non upsampling (0fs) setting in the MU1 with piano music. Calling the transient in the Midnight Sugar track ‘overly sharp’ and even ‘the piano can rip the listener’s ear off’. It got me curious and also puzzled. I’ll try to explain: Although I have preferred the 4fs upsampling since the first day with the MU1 (and actually never touch it since), I tried if I could reproduce your findings. Well, long story short: no. On the contrary actually. I downloaded Midnight Sugar the album (great album btw, thanks!), and must say that I clearly prefer the 4fs setting compared with the 0fs setting (didn’t brother with the 2fs setting). This said, I’m not questioning your findings. But find it interesting what makes that things differ. And thinking more about it, I wonder if the way of testing could have anything to do with it.

 

Hi @FredM this is fantastic. This is what it's all about. Read what I have to say, then listen for yourself. Never take what I say about my experience, with my ears and my system n my room, as the gospel. 

 

Part of what this boils down to is which initial stage upsampling is preferred by the listener, that of the MU1 or that of the DAC being used. There's no right or wrong. 

 

 

9 hours ago, FredM said:

With upsampling enabled to me it just sound more alive, with more air around the instruments. Also smoother, in a positive way. The strike of a piano key is easier to hear and the tones have a beautiful decay (longer lasting than in a 0fs setting). In more complex pieces, multiple tones just ‘flow’ next to each other and fade out gradually individually. In the specific section (2.25) the piano key is struck hard (and recorded close by?), but the clarity and flow remain. In the 0fs setting it sound (a bit) harsher for me, with less ‘flow’. I would call it an obvious difference (easy to pick in a blind test). Or could the higher Dynamic range (15) of the specific track have something to do with it?

 

What this seems to say is that the upsampling to 4fs in the MU1 is either better than in your DAC or preferred by you more than what's in your DAC. All good. 

 

 

9 hours ago, FredM said:

With countless tuning combinations possible (filter settings, DSP, convolution setting, upsampling inside the DAC, etc), it’s hard to pin point things.

 

Absolutely!

 

 

9 hours ago, FredM said:

Perhaps double upsampling (in MU1 and T+A DAC 200) can lead to mixed results?

 

It isn't double upsampling technically. It's upsampling in the MU1 to 4fs, and in the DAC 200 to its max rate. The first stage is done in the MU1, the rest in the DAC 200, versus all in the DAC 200. Different filters and algorithms should sound different. Both of us have definitely heard this :~)

 

 

9 hours ago, FredM said:

Besides difficulty in reviewing the product itself with the external variables, as a reader it will also be more challenging to get an understanding of the performance of the product (like I have at the moment 😀 ). Perhaps my hifi tuning knowledge is far below average, but I wonder to what extend an average listener/ reader uses these tuning options in practice (and apply specific tuning for specific music).

 

I hear you loud and clear. I really wanted to be able to deliver some clarity, but it just isn't possible with so many options. The only thing I could do was try many of them, and describe what I heard. It's great that you and others have described what you/they heard with the MU1 as well. More data points are good. 

 

 

 

9 hours ago, FredM said:

Looping back to the Grimm MU1, I think it would be interesting if you can try out the Midnight Sugar track with perhaps the tracks above and see how they sound in a minimalist setting (Without the DSP, filters, etc, etc.) Keep it simple. I think that would be closer to (most) users situation, better to understand and more valuable insights. 

 

The MU1 is heading out the door today, back to @Analog Audio of Minnesota

 

 

9 hours ago, FredM said:

Please don’t get me wrong, at first I liked your to approach as a welcome addition to existing reviews. But some results seem to differ quite from what others experience (by MU1 users and other reviews). As a suggestion, perhaps it’s an idea to simplify the evaluation approach for gear and perhaps have a separate paragraph for those who have interest and understanding in advanced filter/tuning settings?

 

No worries. I know you have th best of intentions and it all comes from a good place. The fact that my results are different, is kind of nice to me. I feel very different from most other writers. Not better, just different :~)

 

All feedback and recommendations noted. It's all valuable. Thank you.

[The Computer Audiophile]

20 hours ago, FredM said:

I guess I’m trying to understand why -per type of music- you seem to prefer different upsampling settings (0fs / 4fs).

 

This is actually very common. Here is page 22 of the dCS Vivaldi manual. You can see why people may prefer different filters and type of music may be considered when selecting a filter.

 

 

[The Computer Audiophile]

20 minutes ago, fas42 said:

 

Very strange recording balance to the piano; I've never heard a live instrument present so much 'power' in the transients - did they place a microphone right on top of the right hand strings?

 

Is this typical for how TBM record the sound of the musicians?

This is the specific version I listen to. 
 

https://www.impexrecords.com/midnight-sugar/