I have finished the version 3 listening test which is now in full beta.
I am going to publish in on Github, links to follow.
Currently writing report, just finished stuff on THD, now doing other distortion measures.
I am going to rewrite a few new logbook posts, which more accurately represents THD and IMD.
I am also going to talk about the test development timeline, and Rnonlin, which i have started looking at.
I have also been looking at papers talking the perception of loudness and distortion in relation to dynamic range.
I am finding that masking may be a particularly significant part of the way we experience distortion.
Thursday, 22 January 2015
Monday, 12 January 2015
The final listening test format
After much too-ing and frow-ing and re-evaluation, the final listening test interface is ready.
The listening test format is a double-blind compare and capture i.e. a listener will compare two versions of the same track for loudness, and will set the volume for one version.
This will be done for 10 tracks, some of which are the same.
The tracks will vary in genre, because loudness perception is reportedly so genre dependent.
Although, I believe the dependence is really in the data (tracks) and not in their associated labels.
The distorted tracks will be the ones that listeners change the level of.
Each track will last 30 seconds, and be of the same sampling rate.
This is to keep even comparison and quality in the measurements later on, and to keep the listening windows short so more accurate comparisons in level can be drawn.
Each track will be peak normalized to -10dBFS.
This is to make 'like' comparisons, and reduce any extra distorted caused by DSP due to numbers going beyond the registers size.
The order of tracks will be randomised, to ensure that its not possible to cheat the test by asking someone else what levels they set.
The track volume for the distorted version, will be offset by 0.5, and then modulated with a 0 - 1 slider. This should an an appropriate amount of level variety available to the listeners, without adding too great a range.
The listeners name, age and listening experience will be recorded, as well as the levels set for each track.
There will be another test format, which uses one track.This track will be modulated 4 times using 4 different NLDs. The slider will be present to change the envelope, and the listener will aim for the loudest and clearest response. The point in time and NLD modulation coefficient will be recorded for each listener.
The listening test format is a double-blind compare and capture i.e. a listener will compare two versions of the same track for loudness, and will set the volume for one version.
This will be done for 10 tracks, some of which are the same.
The tracks will vary in genre, because loudness perception is reportedly so genre dependent.
Although, I believe the dependence is really in the data (tracks) and not in their associated labels.
The distorted tracks will be the ones that listeners change the level of.
Each track will last 30 seconds, and be of the same sampling rate.
This is to keep even comparison and quality in the measurements later on, and to keep the listening windows short so more accurate comparisons in level can be drawn.
Each track will be peak normalized to -10dBFS.
This is to make 'like' comparisons, and reduce any extra distorted caused by DSP due to numbers going beyond the registers size.
The order of tracks will be randomised, to ensure that its not possible to cheat the test by asking someone else what levels they set.
The track volume for the distorted version, will be offset by 0.5, and then modulated with a 0 - 1 slider. This should an an appropriate amount of level variety available to the listeners, without adding too great a range.
The listeners name, age and listening experience will be recorded, as well as the levels set for each track.
There will be another test format, which uses one track.This track will be modulated 4 times using 4 different NLDs. The slider will be present to change the envelope, and the listener will aim for the loudest and clearest response. The point in time and NLD modulation coefficient will be recorded for each listener.
Monday, 5 January 2015
How LUFS works.
Please see the LUFS related document in the attached folder.
The program is very close to working now!
More lit review, and starting to think about Rnonlin as a perceptual method of measuring distortion.
Subscribe to:
Posts (Atom)