Recent content by JLM1948

  1. J

    To EQ or not to EQ... that is the question.

    I have absolutely no doubt that the boost in the 100-200Hz octave is perceived as "fuller" sound, and the lift in the 3k-10k range results in increased clarity, which you perceive as "closer".
  2. J

    REW and Testing Electronics - what interface do you like?

    I think it just demonstrates that the M2's output stage does not perform well when one leg is shorted. That is quite common actually. That's the biggest challenge designers of electronically balanced output stages are faced with. THAT and TI are honest with this issue, their datasheets show...
  3. J

    REW and Testing Electronics - what interface do you like?

    I don't disagree with that; indeed it's quite common to note that the analog stages have distortion increasuing with level. What I would like to see is the differnce in distortion, all else being equal, when the connection is balanced vs. when one leg is grounded.
  4. J

    REW and Testing Electronics - what interface do you like?

    I have looked at the documents on the MOTU website and the 6263 datasheet. I couldn't find anything related to distortion being different when one leg of the input is grounded. It is true for output stages that have non-linearities concentrated in the output devices, but for inputs, the...
  5. J

    REW and Testing Electronics - what interface do you like?

    Your demonstration is well known , but it applies generally to push-pull stages, where most of teh distortion is caused by the output devices, not by the drivers. In the case of balanced (or symmetric) input or output stages, the situation is different; there is one input signal that is split...
  6. J

    REW and Testing Electronics - what interface do you like?

    You: "You are free to consider any level of distortion on a connection as valid. " This is definitely what I said. I said applying an unbalanced signal to a balanced input introduces no distortion, as long as the performance of said input is adequate. I'm not telling that distortion does not...
  7. J

    REW and Testing Electronics - what interface do you like?

    Intended or not, it's a perfectly valid connection. Then why do you say that there is distortion when using an unbalanced source? I really doubt the whole signal path is balanced in the interface. It is certainly between the input buffer and the A/D converter, because that's how ESS have...
  8. J

    REW and Testing Electronics - what interface do you like?

    I beg to differ. It's common practice, even in high-end and instrumentation equipment. I understand that as you connect the "balanced "output of whatever your source is to an unbalanced input. If the output stage is not floating, you are shorting the inverting leg to ground, which causes the...
  9. J

    Using REW to Plot Crossover Response Curves?

    Veru likely. Another possible cause of errors is the unbalanced connections. Ground current circulation can offset measurements.
  10. J

    Using REW to Plot Crossover Response Curves?

    0.3dB is a minor error, about 3%. Do you know what your DMM's precision is? And its frequency response. REW is not exempt of error either. What soundcard are you using? Significant error can come from the reference point of the measurement setup.
  11. J

    Using REW to Plot Crossover Response Curves?

    Yes, you must know that noise, after AD conversion and FFT results in bumpy response instead of a nice continuous fraph.
  12. J

    Using REW to Plot Crossover Response Curves?

    Well, it looks like there is a notch in the response at about 5k, on which LTspice and REW agree. The fuzziness is just noise. I suggest you do the same measurement with the input signal muted (but with the amp and soundcard connected). You'll see the same fuzziness.
  13. J

    Separate In and Out interfaces...possible feature request

    I use it for measurements. When all is said and done I should be capable of measuring frequency response, oscillations and ringing up to 180kHz.
  14. J

    Separate In and Out interfaces...possible feature request

    IIRC, John mentioned issues with ASIO4ALL at 384kHz SR
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