by wdbames » December 16th, 2005, 5:31 pm
[quote="davelowe1977"][quote="dgrade"]
One thing that is important to remember though is if you're saving your work in MP3 format do not let your encoder save it in "Joint Stereo" or (J-Stereo) as that completely blows the whole point. Also if you have 5.1 Stereo Headset make sure you set your sound card to only output 2/2.1 while you're listening to any binaural (for Creative soundcards you must use the Creative Audio Console, not the Windows Sound manager).[/quote]
That is an interesting and very true point. In my mind it opens a can of worms about the effectiveness of all the subliminal files.
Quick revision: topic file compression (for the non-techies!):
mp3 format is a lossy type of file compression. One of the ways this works is to eliminate sounds that cannot be heard by the (conscious) mind, methodologies include 'masking' etc. Masking occurs when a loud sound at one frequency masks a quieter one at a slightly different frequency so they are not included in the file. The file sounds identical to a non compressed format (ie .wav) on commercial tracks. zip files by contrast offer less compression (bigger files) but is loss-less (ie the full content can be completely re-assembled during de-compression). End of technical advice.
Now to the point. If the techniques employed in mp3 compression (such as masking) mask the sound of the voice in a subliminal (by using white (broad frequency noise), can we expect them to work? There are several answers: yes, no or maybe. A full scale scientific trial would answer this question, but in lieu of more informed advice, we are not likely to find an answer unless we undertake a study or employ expert advice. One answer might be to use noise at a suitable sound level but excluding frequencies that are essential to vocal communication (similar to telephone limitations). Another answer might be to distribute the subliminals in a zipped .wav format. Maybe the subconscious fills in the gaps in the missing sound (I doubt this). My only goal in discussing this subject is to improve the effectiveness of the subliminals if this even needs to be done. Maybe this lossy effect helps the subliminals (again doubt) Either way, I salute the efforts of EMG and jerm et al in making these files and can only hope my thoughts will help.
I open the floor to discussion!
----- Dave (part time audio engineer)[/quote]
We're straying off the subject of binaurals, however I concede the possibility that subliminals could become a problem in MP3 at too low of a bitrate. I see two possible approaches:
1. Raise the bitrate to an acceptable level, if there is one. This would involve some research and experimentation.
2. Switch to "Supraliminals." This involves keeping the message at a high volume, but increasing the audio frequency to around 15.5KHz. Which is at the fringe of the audible range. Assuming MP3 can perform acceptably at this frequency, we should be O.K. Next overlay binaural beat music and compress to a suitable MP3 stream. I have tried this approach and found it at least as effective as subliminals.
If anyone has more information on these topics, I invite comment, Correction, Clarification, or even a flame if You feel I'm way off base. :)
WDBames
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You are relaxed and obedient....
So completely relaxed.