Meeting: 9/14/2010

This meeting was held to discuss the next stages of our current perceptual test, which is to determine if expert listeners are able to differentiate between 2 vinyl record playback systems of differing price ranges. Each system includes a cartridge, turntable, preamplifier, and interconnect cables. The meeting was attended by Ichiro Fujinaga, Catherine Guastavino, David Weigl, and myself (Jason Hockman). The following are notes take from the meeting:

We will perform a study that will test participants' discrimination through preference testing.

This test will be based on a preference of system 1 or system 2, however subjects will also be tested using a comparison of different recordings of the same system, due to the variability inherent in the analog recording process. More specifically, we feel it necessary to include this "A1-A2" testing because playback of vinyl records can result in clicks and pops which may be found in different places within the digitally recorded timeseries, as well as possibly audible record degradation. Subjects will be informed in the preamble of the experiment that this will be part of the test, so they will not feel deceived by the test setup.

In a previous listening test (see the MP3 study here) started w/ 40 mins - 1 hour of audio material to listen to. Subjects were allowed to listen as many times as they wished, and could move between listening examples. We will adopt a similar structure for our experiment.

So how will we choose the files? is there a particular type of sound we are looking for? how long will the files be? The previous study used 5-12 sec. clips. Our study will instead utilize longer clips, as audiophiles will most likely require longer clips for analysis, but this makes the number of different clips heard overwhelming.

The final decision was to identify from our library 8 audio excerpts, of approximately 15 seconds each.

The participant should be able to switch between the 2 systems with a button. Upon pressing the button, there should be a fade-out of the first track followed by a 200-ms silence buffer and fade-in.

The interface should consist of this A/B switching button, a start (from beginning) button, as well as play, pause. Not discussed in the meeting, but assumed by myself is the need of "stop" and "next sample" buttons.

We will need background and response questionnaires, and receipt forms. Catherine has these forms from the previous MP3 experiment, and she will send these to David.

Timeline:

• recordings and pilot will be done in October
• study will take place in November
  

To do:

• book headphones
• once headphones are booked, verify the difficulty in differentiating between 2 systems.
• contact Harold about our timeline and requirements for the critical listening room for November
• set David up with a MAQ page account
• make copies of music for Catherine, Ich, and David for selecting musical clips