Recent content by jschwender

  1. J

    REW fails to output sound on Linux

    As UMIK comes with cal file, you don't need loopback for calibrating. For timing reference you can use acoustic signal in the measurement. If you start pulsseaudio after REW, that works because access to device is locking, and preventing other applications from access. Like if you have REW...
  2. J

    REW fails to output sound on Linux

    for acoustic measurements, a USB microphone like UMIK-1 has the advantage that it is simple. I have a UMIK-2 and it does not have any mixer controls, switches or something you can screw up. You plug it in, an alsa-device appears and REW does recognize it properly. Very user friendly.
  3. J

    REW fails to output sound on Linux

    pulseaudio or wine is not a good choice, it makes things unpredictable. pusleaudio is very good for destop application, as it allows to transparently join multiple audio streams with different rates or resolution and run them through network or your speakers. This signal path may utilize...
  4. J

    How to build an impedance measurement rig using an amplifier

    Yes, it does. More or less. Metallic alloy cores and some ferrite core materials mostly have a wide linear range, that goes pretty sharp into saturation. Powder cores have more a soft transition to saturation, or in other words they are mostly non-linear. If you have a core it is important to...
  5. J

    How to build an impedance measurement rig using an amplifier

    Do you mean the resitor itself causes thermal distortion? The resistor is a 50W with ayrton-perry winding and 20 ppm temperature coefficient, that is at least much lower than copper in objects. In theory power load could be 100%, but i never did that, usually i apply signal like 6 Veff on the...
  6. J

    How to build an impedance measurement rig using an amplifier

    That is amazing, it means that your setup must have 120 dB usable dynamic range (1000 Ohm to milliohm). So your milliohm results have only very limited accuracy, right? The systematic error is minimum if the object resistance has the same value as the reference resistor, below or above the...
  7. J

    How to build an impedance measurement rig using an amplifier

    If you have only one input (mono) impedance measurement will not work. It takes two and they should have best matching in their characteristics and need to utilize the same analog to digital converter to run synchronously. Having only one input is also for frequency response measurement a...
  8. J

    Feature requests for loudspeaker design

    Please, can you explain what you mean by protection capacitor?
  9. J

    How to build an impedance measurement rig using an amplifier

    I use an external amplifier and a 29 and 4 ohm precision resistor with Ayrton-Perry-winding built in, and a 1/10 voltage divider built in. Works pretty well for impedance measurement between 10 mOhm to approximately 1 k Ohm. The amplifier has 10,0x amplification, and i can do measurements up 12...
  10. J

    Bang & Olufsen BeoLab 8000

    I had a set of them until 2015. They look fantastic. As the Beosound 9000 device died i could not use the RCA inputs direct to cd player - lot of hum. I Modified them and refurbished them completely. At the end they were not powerful enough. I think ok for small rooms, so i sold them.
  11. J

    run REW with different set of fixed settings

    Thank you for your support!. If you like, you might want to mention that this file is erased and newly written on REW restart. Therefore it does not work to make it a symbolic link, which was my first approch to manage set of settings. Creating the directory above as a symbolic link works (for me).
  12. J

    run REW with different set of fixed settings

    ok, your hint helped, now found it: ~/.java/.userPrefs/room eq wizard/prefs.xml
  13. J

    run REW with different set of fixed settings

    Sorry, i forgot to mention that i am on Linux, do you know how it works there?
  14. J

    REW and Testing Electronics - what interface do you like?

    Different device, similar effect. I used the M2 to generate a signal of FS level and fed that into the Steinberg UR22. One time asymmetric only to the (+) leg, one time to the (-) leg and one time as symmetric signal. 2nd harmonic is much lower with sym input.
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