Tonality control adds a lot of noise (Bass only, in fact)

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7 Kommentare

  • RaoulJ

    OK, so adding more details

    I measured using Audio Precision Multi Tone 32 signal (24 bits 48kHz)
    The signal is in a WAV file on my computer, shared with the Node 100.
    It's then played through SPDIF output to an RME ADI-2/4 Pro SE.
    The RME is connected to my PC with USB
    So the signal path is purely digital: No analog conversion.
    Measurement is done using Virtins Multi Instrument 3.9.9.2
    NB: Don't worry about the Voltage measurement. It's just wrong.

    Here is the measurement when tone control is disabled


    Here it is when I switch Tone control on, but all controls are on 0dB


    We lose only 10dB (6dB of which are due to the -6dB level change to avoid saturation)
    That's pretty good actually.

    Now with some Trebble change (-6dB)


    This has very little impact. This is the worst case scenario: all other trebble settings are better.

    But what happens if we dare to touch Bass control ?


    It doesn't even cover the CD dynamic range - and still in full digital 24 bits !
    We've lost 36dB of dynamic range just by modifying bass level by 0.5dB.

    All other bass settings give similar results.

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  • RaoulJ

    Of course, that does have very little impact on the analog output, since this one is VERY weak...
    But I only use the Node 100 with its digital output, anyway.

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  • RaoulJ

    Measuring the same signal through Analog output, the best result we get is for -12dB volume

    because at 0dB or fixed volume, the output is saturating:
    It's 0.23% TD+N, which is not good

    As from -1dB (2 notches below max level), we get results close to the "best".

    Again, this saturation only occurs in the Analog path.
    There is no such thing in digital domain, as the measurements in the post above show.

    Bottom line: with analog output, don't use fixed volume, but lower the level by 2 notches at least for best results.

    By the way, there is very little impact of the volume control on sound quality.
    We can check that by comparing the (pure digital) output through SPDIF at full / fixed volume (identical)

    to the results with a small level decrease

    This difference is negligible, of course.
    So the level control itself is well implemented.

     

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  • RaoulJ

    Tested today on my brand new Node N132
    BluOS 4.8.15

    This stupid bug is still there:

    Digital loopback with Tone control in
    All is OK

    Same with Bass correction -0.5dB
    We loose 40dB of dynamic range !

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  • RaoulJ

    And in case you're wondering weither that makes a difference on the analog output for the Node 2025 (N132), the answer is YES

     

    Without tone control

    With Tone control active

    With Bass -0.5dB

    30dB loss !
    We are now more than 20dB below CD quality 

    That kind of thing makes the difference between "Good enough" and not !
    Why to invest in a good DAC chip and a "correct" implementation of it, if that's to eventually screw it with a poor software ?

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  • RaoulJ

    Would you guys mind acknowledging this ?

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  • Alan Dang

    This has also been reported by end users at AudioScienceReview with the flagship Node Icon.

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