Mass project

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Revision as of 17:21, 31 July 2006 by Hiroko (Talk | contribs) (parameters)

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Welcome to the Masking Ambient Speech Sounds project Wiki. The project is on-track to begin listening trials on the 21st of July.


Experiment 1

The first listening tests will involve project staff members to check if things make sense. If it looks good we'll start working with non-project volunteers. Experiment 1, in the the CCRMA "Pit," will take about 30 mins. and involve 30 trials. There will be 6 conditions of masking sound crossed with 5 conditions of speech sounds. The masker (FM noise) and the speech sounds will be presented as if the sources are outside the room. We'll use the measured room model from Tokyo and the exterior sound source position (hallway). The "as if" impression will be created by convolving with the measured impulse responses.

Necessary ingredients: (x = done)

  1. (x) ambient room sound recording from Tokyo
  2. (x) 15 sec. recordings of FM noise masker with parameter variation
  3. (x) 4 min. recordings of 4 conversations (animated / not-animated, crowd / pair, always 50% gender balance)
  4. (x) 15 sec. clips cut from conversations
  5. (x) convolved versions of 15 sec. files putting them "as if" in the hallway
  6. (x) GUI for running randomized listening, A/B forced choice, logging results


Strategies to define conditions for FM masing noise

To define the conditions of this first experiment, the approach will be to leave all the parameters fixed, except the modulation frequency.

Noise set Contains a complete technical documentation of the masking noise generation. It also contains the soundfiles.

The conditions of the masking FM noise will be defined by the following criteria:

  • 3 bands of FM noise will be used (centered at 200 350 and 500 Hz):
    This bands are selected based on an analysis of speech voice recorded in the Tokyo office. The motivation behind this decision is to identify the relevant parameters in the leaking voice. For example, we know that the wall is filtering much of the high frequency components, so that's relevant in the selection of the main frequencies.
  • The amplitude (volume) of each band will be fixed:
    The amplitude was tuned in order to psychoacoustically balance the level of the three noise bands that will be used. This balance was done without modulation.
  • The amplitude of the modulation will be proportional to the modulation frequency:
    The motivation behind this choice is to minimize the annoyance effect. When the modulation rate is low, higher amplitudes are more noticed and annoying.
  • The relation between of modulation frequency of the 3 bands is then the main factor to define the conditions:
    For this experiment, 3 modulation rates are selected, 2, 5 and 7 Hz. The idea is to span some of the frequencies in the range of 2 to 7 Hz. Basically, all the combination of these 3 rates are used for each center frequency, plus a case with no modulation at all.

--Jcaceres 17:09, 24 July 2006 (PDT)

The beta-test of the experiment tool took longer than anticipated. Some minor fixes remain. The ones I remember from yesterday (Friday, 28th) and the ToDo list for Monday (x = done):

  1. delete input slider from bottom of GUI (in Qt Designer), final product should look like the picture above
  2. when user hits "OK, Next" button, clear all the radiobuttons, with radiobutton->setDown(false)
  3. comment out all the "cout" statements that are printing during trials, except for the one that says "behind"
  4. find a sticky way to keep machine speed at max during trial (automatic energy saving may be the reason for the occasional stuttering)
  5. (x) convert QString to const char for logger class file open (use const char * QString::latin1 ())
  6. create a "shuffle" sort method in MainDialog.cpp and apply it for the actual first test
  7. I think each individual mono file repeating is ok, but I'm worried that they could slip out of sync. Don't know for sure. Better if the repeats for a group of four is from the first channel's repeat
  8. add envelopes at all file starts, stops, repeats (with STK's Asymp class), pipe the file's output through it
  9. IF I've created a problem for disk files keeping up, you will see the message "behind" printed from FileWvIn and it will start stuttering, the next fix to try (and this might be important anyway for our sanity) is to go to quad files rather than 4 mono files for each layer.

_____________ there are probably more things I'm forgetting, but this is close

--Cc 09:42, 29 July 2006 (PDT)

Conference Call Meetings

July 18, 2006

  • FM Modulation discussion (Yasushi's Comments, with Juan-Pablo's comment on answer A:):
  1. Do you have any idea how to specify frequency modulation for each frequency band?
    • A: based on speech freq, ~2-8 Hz
  2. The period in time for each frequency should be the same?
    • A: No, different. When it's the same the masking efficiency decreases. It seems also more anoying.
  3. Modulation speed will be getting faster according to higher frequency, or
    • A: I don't know yet, this is going to be the main parameter in the first experiment I think.
  4. The frequency modulation considering the voice sound
  5. We have to analyze how the voice sound is modulated in different frequency bands?
    • A: I thiks this is the best way, and we have to consider that the wall is filtering almost all the high frequencies.
  • Discussion of the experiment setup.
  • Look at the documentation, the new example of impulse responses, and delay of arrival.

July 24, 2006

Tuesday 9:30AM Japan - Monday 5:30PM Stanford

  • Discuss Experiment 1.
  • Ask Atsuko about calibration files and SPL meeter.
  • Comment diffusion in the Pit with PZM system (Hiroko).
  • Discuss Experiment Design writen by Hiroko and Atsuko.

July 31, 2006

Tuesday 9:30AM Japan - Monday 5:30PM Stanford

  • Discuss Experiment Design writen by Hiroko and Atsuko.
  • Explain experiment setup.
  • Discuss Atsuko's agenda at CCRMA.
  • Goals for this week are to finsih the setup (C++ and pit room) and collect and analyse some data in a couple of subjects.


  • modulation width (critical band or speech frequencies)
  • band width of the noise (critical band)
  • modulation frequency (2, 5, 7 or more?)
  • number of center frequencies (0, 3, 8)
  • levels of the channels ()
  • with or without broadband noise (0, med, high)