Either dBUu(0.775V) or dBV (1V) could be used, however smartphones may not be able to reach those voltages. I would always go for dBV and state the reference when that's not possible. Jds specs -105 dBu (4.3 uVrms) for the headphone amp and -103 dBu (5.4 uVrms) for the dac, Your measurements...

Hey haku, what's the reference in those measurements (The 0dB output voltage of the device when it was measured)? So i can have an idea of the noise levels.

Hey can somebody recommend some dirty cheap ba iems which impedance varies a lot? So far I've found these, don't know if there's something at a similar price that varies even more: http://reference-audio-analyzer.pro/en/report/hp/kz-zst.php

Thanks a lot. I know you have (or had) a FiiO X7, because I checked your profile (you have a review of it). xD   ~2 Vrms 33 Ohm, very nice, that's even more than what the dragonfly red can output at that load (it clips @1 Vrms with 32 Ohm load).  ...

  Can you measure its max output power into the 32 Ohm load? Just set up everything as if you were going to run a RMAA test with the load in parallel, generate a 0dB 1 KHz tone in audacity, hit record only in RMAA (and don't go any further, you can use the RMAA's calibration to determine if the...

  Unloaded measurements don't say much about the real performance of the device. The only thing that can be said of those is that the walnut sucks.   And the channel imbalance is because of the potentiometer of the walnut. Usually you want it to be under 1dB from its max output voltage (the...

  He's calling his measurements inaccurate because his multimeter accuracy is off by 0.33 dB. xd I told that's fine.      

Because it has a series inductor.     Edit: nvm, thought you where asking why high frequencies drop with a load. Chris already stated that is because of the aliasing filter of his PC.

  Add a 0 dB tone to your music, that way you can perfectly match volume before recording. Once done, remove the tone before uploading the files.   And the tone also tells you if you're clipping the input (going over its max input voltage).   For example, it seems I was drunk when I...

  I would like to have the two files separated so I could perform an ABX test on foobar2000. That's the method I use.   I actually have a Samsung Galaxy Ace (the first one) recorded driving an 80 ohm load, and the original file had to be converted to AAC in order to record it (Cuz the phone...

  There's actually a video on one of the tutorials on r/headphones that literary implies that you have to do the power calculations dB/mW at the impedance peak of the headphones, a while back I sent feedback asking them to fix that and to this day the video is still there. xd   I would think...

  It would be great if you could report the output impedance, though you need resistors.   A way to measure output impedance is to use the calibration test in rightmark, create a 0 dBFS tone, hit "recording only" on rightmark, play the tone and increase the volume until it says -1 dB, then...

Today I tested two Blu phones. A Blu advance 4.0 L2 and a Blu Studio 7.0.   Output impedance:   @1 KHz Advance 4.0 L2 = 65 Ohm. Studio 7.0 = 88 Ohm.   @120 Hz Advance 4.0 L2 = 110 Ohm. Studio 7.0 = 122 Ohm.   This means both have output caps.   So I tested them with rightmark, with...

  High output impedance and or small output coupling capacitors are the most common source of problems.   Listen to these: https://mega.nz/#!sUgxzRgS!JLTybF_ElfTmROh6pzDngcP8wJoRqA2Sm2V5fZxq-BA   That motherboard has terribly small output coupling capacitors, even with a 320 Ohm completely...

    Do you hear hiss with the HD650? Hiss is usually an issue with sensitive headphones, it really needs to be terrible for it to be perceptible in headphones like the HD650, If you hear it with the 650s that would mean that noise is higher than 65 uVrms.  What do you mean with greater dynamic...

  With high impedance headphones the only requirements is that whatever the source is, it needs to output enough voltage for them . They're not affected by high output impedances or small coupling capacitors like low impedance headphones, and they draw very little current, so distortion is...

  I actually find hard to believe that the odac+o2 is a bit cleaner. How did you set up the blind test? A proper blind test needs a perfectly match volume in both devices and to do so you need a decent multimeter, and also perfectly sync both devices which I find very difficult/impossible, and...

Archimago's measured a 33 Ohm output impedance in the Nexus 7 2nd gen at 1 KHz, though he didn't test it at lower frequencies..

  You can't adjust levels by ear. How do you know that whatever device that's being tested is outputting say 1 Vrms? You could in theory adjust levels with the ADC of your PC if you have a device with a known max output voltage at 0 dBFS. But my god, it is going to be a complete hassle. With a...

http://image.prntscr.com/image/36a5bed4120c44fb83104eccfb73e343.png   What?   Anyway xd, C1, 2, 3, 4, 5 and 6, two of those capacitors have to be in series with the headphones jack, Also it seems they added bleeding resistors (R14, R5, etc) (they reduce the "pop" when you connect the...

   It would be great to know the capacitance of the output capacitors, open the thing up and check the capacitors. And also the output opamp (To know the model). It can easily be fixed by replacing the output caps for bigger ones. (>1000 uF).   It's likely that the output stage directly works...

You can still use the ADC of your PC to measure output impedance. By comparing the amplitude drop at the line in when you add a load to the device being recorded. I've found that method to be quite precise, you need custom cabling though. And make sure to prevent clipping either from the ADC or...

http://www.mediafire.com/download/av6k1rhkv5lwol6/Superlux+HD681+EVO.pdf

  Make one.    http://prnt.sc/97niqx http://prnt.sc/97nj5v http://prnt.sc/97njj4

Why don't you post the whole report as an screenshot?    I use this: https://chrome.google.com/webstore/detail/full-page-screen-capture/fdpohaocaechififmbbbbbknoalclacl?utm_source=chrome-app-launcher-info-dialog   Example: http://i.imgur.com/wLZcTb4.png