Matrix Audio X-Sabre Pro technical measurements

Discussion in 'Source Measurements' started by atomicbob, May 15, 2020.

  1. atomicbob

    atomicbob dScope Yoda

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    Matrix Audio X-Sabre Pro (Matrix XSP) technical measurements
    This is the non-MQA version. I have no use for MQA.

    Standard Prologue
    If you are unfamiliar with audio measurements please use a search engine with the query:
    "audio measurements" or "audio measurement handbook"
    Look for publications by Richard C. Cabot and also by Bob Metzler, both from Audio Precision. There are other useful publications as well. These will provide basic knowledge.
    Interpretation of the following measurements is beyond the scope of technical measurements posts.

    The data presented were collected as follows:

    1. PrismSound dScope III, picoscope 5243B, Cal Test CT2593-2 balanced probe
    2. Tecnec 75R spdif cable
    3. Balanced XLR cables Belden 1800F with Neutrik 110R AES connectors
    4. Single Ended cables Mogami 2964 1 meter with Amphenol RCA connectors
    5. 100 Kohm load used for measurements
    6. dScope analyzer sample rate 48 KHz unless otherwise noted
    7. DAC 44.1 KHz sample rate, 24 bit depth unless otherwise noted
    9. Audioquest Forest and Schiit Pyst USB cables
    9. Vaunix Lab Brick USB hub
    10. Shielded 14AWG and 16AWG power cables
    11. Filter mode 3 unless otherwise noted
    12. DAC settings
    a) Preamp mode
    b) Dither ON
    c) Filter 3
    d) DSD 47 KHz
    e) Line OUt 0 dB
    f) Jitter reduction OFF
    g) DAC Mode Sync
    h) Firmware version 1.82

    Measurements are made in accordance with AES17:2015

    Why I measure multiple digital inputs on DACs.
    AES/EBU and spdif inputs are important for use in my acoustic lab. The lab is wired for Dante AOIP delivery in multiple locations. DACs are easily AB and ABX compared with synchronized identical source data streams from Dante to AES or spdif bridges. Running USB AB and ABX comparisons involves a lot more effort to maintain synchronization. I am not concerned with short AB or ABX but find it distracting to change setups during listening exercises. Flipping a switch between synchronized level matched DACs minimizes distrations allowing better auditory focus.

    Often a given DAC has been optimized for best measured results on the ASIO USB input and the other digital inputs fall a bit short. Better DAC design supports nearly the same performance on the various digital inputs.

    Matrix Audio XSP
    Measurements for record commenced after warmup of 2 hours.
    Measurements were performed over a period of several days.

    Index
    Post 1 - measurement setup description, highlights
    Post 2 - AES input - Bal XLR outputs part A
    Post 3 - AES input - SE RCA outputs part B
    Post 4 - USB ASIO input - Bal XLR outputs part C
    Post 5 - USB ASIO input - SE RCA outputs part D
    Post 6 - Filter response
    Post 7 - Filter ringing vs dBFS level
    Post 8 - reserved for additional data and corrections

    Notable highlights:
    Ultra low distortion
    Power supply noise spectrum are typically at or below -160 dBFS in balanced output
    The power supply spectrum residual noise was so low it was necessary to reconfigure y-axis scale low enough to see the noise floor.
    Balanced output Dynamic Range of > 140 dB
    Balanced output Cross-talk is dual mono with > 148 dB isolation
    Balanced output Gain Linearity is nearly perfect to -115 dBFS, less than ± 1 dB to -130 dBFS, AES input
    Balanced output Gain Linearity is nearly perfect to -125 dBFS, less than ± 0.25 dB to -130 dBFS, USB ASIO input
    Exceptionally low jitter
    Single Ended performance is somewhat less than Balanced output, as is typical
    Single Ended performance is still exceptional compared to other DAC SE outputs

    Well done Matrix Audio!

    Commentary:
    Power supply is at least 50% of any audio component's design. The higher the level of performance the more the power supply matters. Matrix Audio demonstrates understanding of this detail and has employed milled aluminum chassis for internal isolation, enhanced XSP's power supply, keeping noise to 100s of nanovolt levels while supplying 10s of volts throughout the system. This is an exceptional achievement. Every aspect of performance has been scrutinized and optimized. The result is an equally impressive neutral presentation, allowing one to observe amplifer character with ease. I have my pairing favorites, based on my personal preferences.

    Measurement setup picture example:
    DSC_0433_small.jpg

    Listening pictures
    More than usual listening session hours disappeared while evaluating Matrix XSP with a variety of headphone amps. After the ESS 9018 and 9028 designs, I never thought I would find myself enjoying anything from ESS ever again. I have enjoyed this DAC so much as to buy one for myself. Here are a few of my favorites DAC - Headamp combinations:

    DSC_0137_small.jpg

    DSC_0145_small.jpg
     
    Last edited: May 15, 2020
  2. atomicbob

    atomicbob dScope Yoda

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    AES input Bal output measurements part A

    Matrix XSP Dynamic Range spdif input Bal output
    20200508 Matrix XSP dynamic range FFT AES Bal.png
    Excellent performance

    Dynamic range, in simplified terms
    1. find maximum output voltage at 0 dBFS
    2. find residual noise with a -60 dBFS 1 KHz stimulus, removed from analysis by window notch
    3. Dynamic Range is the difference between maximum output and residual noise
    Specifics are in AES17 section 9.3 (measurebators do your homework please)
    Example here:
    https://www.maximintegrated.com/en/design/blog/spec-dynamic-range.html

    Why we have a -60 dBFS stimulus
    Some clever codec designers include an output gate that shuts off when there is no signal present. This has the dual benefit of lowering output idle noise while also gaming the measurements. AES became wise requiring a -60 dBFS stimulus so any such gates are open during measurement and true Dynamic Range performance measured.

    Matrix XSP -120dBFS sine AES input Bal output
    FFT_0_L1T18_1.png
    Sine at -120 dBFS is excellent. Very few DACs can achieve this level of resolution at this time.

    Matrix XSP A04 THD+N THD nth-HD FFT AES input Bal output
    20200508 Matrix XSP A04 THD+N THD nth-HD 4+HD+N 60Hz FFT 0dBFS - AES Bal.png
    Are there enough zeros in the various distortion measurements on that graph??

    Matrix XSP 50 + 7000 Hz AES input Bal output - Left Channel
    FFT_2_L1T13_1_A.png

    Matrix XSP Gain Linearity AES input Bal output - Left Channel
    G2_L1T3_1_A.png
    Perfect to below -115 dBFS then ±0.5 dB to -125 dBFS and just above 1 dB off at -130 dBFS.

    Matrix XSP THD+N vs Frequency AES input Bal output - Left Channel
    G2_L1T5_1_A.png

    Matrix XSP Residual Noise Bal AES input Bal output - Left Channel
    FFT_2_L1T16_1_A.png
    The residual noise spectrum is below -170 dBFS above 15 Hz!!!


    Complete AES input Bal output analysis report pdf attached
     

    Attached Files:

    Last edited: May 15, 2020
  3. atomicbob

    atomicbob dScope Yoda

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    AES input SE output measurements part B

    Matrix XSP A04 THD+N THD nth-HD FFT AES input SE output
    20200507 Matrix XSP A04 THD+N THD nth-HD 4+HD+N 60Hz FFT 0dBFS - AES SE.png

    Matrix XSP 50 + 7000 Hz AES input SE output - Left Channel
    FFT_2_L1T13_1_A.png

    Matrix XSP Gain Linearity AES input SE output - Left Channel
    G2_L1T3_1_A.png

    Matrix XSP THD+N vs Frequency AES input SE output - Left Channel
    G2_L1T5_1_A.png

    Matrix XSP Residual Noise AES input SE output - Left Channel
    FFT_2_L1T16_1_A.png

    Complete AES input SE output analysis report pdf attached
     

    Attached Files:

    Last edited: May 15, 2020
  4. atomicbob

    atomicbob dScope Yoda

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    USB ASIO input Bal output measurements part C

    Matrix XSP Dynamic Range USB input Bal output
    20200508 Matrix XSP dynamic range FFT ASIO Bal.png
    Beyond impressive at > 141 dB dynamic range.

    Matrix XSP -120dBFS sine USB input Bal output
    FFT_0_L1T18_1.png
    Also very impressive.

    Matrix XSP A04 THD+N THD nth-HD FFT USB input Bal output
    20200508 Matrix XSP A04 THD+N THD nth-HD 4+HD+N 60Hz FFT 0dBFS - ASIO Bal.png
    Enough zeros in that graph?

    Matrix XSP 50 + 7000 Hz USB input Bal output - Left Channel
    FFT_2_L1T13_1_A.png

    Matrix XSP Gain Linearity USB input Bal output - Left Channel
    G2_L1T3_1_A.png
    Nearly perfect to -125 dBFS and then only off by -0.25 dB at -130 dBFS. Impressive.

    Matrix XSP THD+N vs Frequency USB input Bal output - Left Channel
    G2_L1T5_1_A.png

    Matrix XSP Residual Noise Bal USB input Bal output - Left Channel
    FFT_2_L1T16_1_A.png
    Again, impressive.

    Complete USB input Bal output analysis report pdf attached
     

    Attached Files:

    Last edited: May 15, 2020
  5. atomicbob

    atomicbob dScope Yoda

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    USB ASIO input SE output measurements part D

    Matrix XSP A04 THD+N THD nth-HD FFT USB input SE output
    20200508 Matrix XSP A04 THD+N THD nth-HD 4+HD+N 60Hz FFT 0dBFS - ASIO SE.png

    Matrix XSP 50 + 7000 Hz USB input SE output - Left Channel
    FFT_2_L1T13_1_A.png

    Matrix XSP Gain Linearity USB input SE output - Left Channel
    G2_L1T3_1_A.png
    Single ended output certainly does not appear to be deficient in gain linearity compared to Bal output.

    Matrix XSP THD+N vs Frequency USB input SE output - Left Channel
    G2_L1T5_1_A.png

    Matrix XSP Residual Noise USB input SE output - Left Channel
    FFT_2_L1T16_1_A.png

    Complete USB input SE output analysis report pdf attached
     

    Attached Files:

    Last edited: May 15, 2020
  6. atomicbob

    atomicbob dScope Yoda

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    Filter Response

    Measurement conditions
    1. -3.5 dBFS 20Hz square wave
    2. 44.1 KHz sample rate
    3. USB ASIO input
    4. SE output to oscilloscope

    It was necessary to use -3.5 dBFS digital gain to avoid DAC recovery filter clipping during the filter ring for Filter Mode 1 and 2. Other modes clip the filter ring at above -2.0 dBFS. All modes were measured with -3.5 dBFS digital gain applied.

    Matrix XSP 100uS/div Filter 1
    20200508-41 Matrix XSP fltr1 20 Hz sqr -3_5 dBFS 4_00 Vpp 100uS div AES SE.PNG

    Matrix XSP 100uS/div Filter 2
    20200508-42 Matrix XSP fltr2 20 Hz sqr -3_5 dBFS 4_00 Vpp 100uS div AES SE.PNG

    Matrix XSP 100uS/div Filter 3
    20200508-43 Matrix XSP fltr3 20 Hz sqr -3_5 dBFS 4_00 Vpp 100uS div AES SE.PNG

    Matrix XSP 100uS/div Filter 4
    20200508-44 Matrix XSP fltr4 20 Hz sqr -3_5 dBFS 4_00 Vpp 100uS div AES SE.PNG

    Matrix XSP 100uS/div Filter 5
    20200508-45 Matrix XSP fltr5 20 Hz sqr -3_5 dBFS 4_00 Vpp 100uS div AES SE.PNG

    Matrix XSP 100uS/div Filter 6
    20200508-46 Matrix XSP fltr6 20 Hz sqr -3_5 dBFS 4_00 Vpp 100uS div AES SE.PNG

    Matrix XSP 100uS/div Filter 7
    20200508-47 Matrix XSP fltr7 20 Hz sqr -3_5 dBFS 4_00 Vpp 100uS div AES SE.PNG
     
    Last edited: May 15, 2020
  7. atomicbob

    atomicbob dScope Yoda

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    Filter ringing vs dBFS level

    Measurement conditions
    1. 20Hz square wave
    2. 44.1 KHz sample rate
    3. USB ASIO input
    4. SE output to oscilloscope
    5. Filter mode 3

    DAC anti-alias filter ringing can clip on fast transition signals. Leading edges of percussive sounds often have transitions that are nearly that of a square wave which will stimulate filter ringing. All OS DACs have this trait. Most DAC manufacturers gain stage the DAC such that a 0 dBFS sine is just below the power supply limits and thus doesn't clip. When the filter rings, clipping occurs. Using digital attenuation can avoid this unwanted signal modification. How much attenuation is dependent on the filter design. Here is an example for Matrix XSP Filter Mode 3.

    Matrix XSP 50uS/div 0.0 dBFS
    20200508-30 Matrix XSP fltr3 20 Hz sqr -0_0 dBFS 6_00 Vpp 50uS div AES SE.PNG
    Note clipping on both ring peaks

    Matrix XSP 50uS/div -0.5 dBFS
    20200508-31 Matrix XSP fltr3 20 Hz sqr -0_5 dBFS 5_66 Vpp 50uS div AES SE.PNG

    Matrix XSP 50uS/div -1.0 dBFS
    20200508-32 Matrix XSP fltr3 20 Hz sqr -1_0 dBFS 5_35 Vpp 50uS div AES SE.PNG

    Matrix XSP 50uS/div -1.5 dBFS
    20200508-33 Matrix XSP fltr3 20 Hz sqr -1_5 dBFS 5_05 Vpp 50uS div AES SE.PNG
    Positive going ring peak still slightly clipped.

    Matrix XSP 50uS/div -2.0 dBFS
    20200508-34 Matrix XSP fltr3 20 Hz sqr -2_0 dBFS 4_77 Vpp 50uS div AES SE.PNG
    No clipping.
     
    Last edited: May 15, 2020
  8. atomicbob

    atomicbob dScope Yoda

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    reserved for additional data and corrections.
     
  9. magicwonder

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    Hi, good post, what is the second headphone amp with the silver box with stripes?
     
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