Lectorum Salutum!
I came across an interesting report on Digital Audio Projection. The full report was sprinkled with copyright notices and threats of punishment if copied unauthorized so I just cut out an exerpt, see below.
Does anyone have experienced such a system or knows more about its performance? Is this the end of speakers farms?
Jan Didden
I came across an interesting report on Digital Audio Projection. The full report was sprinkled with copyright notices and threats of punishment if copied unauthorized so I just cut out an exerpt, see below.
Does anyone have experienced such a system or knows more about its performance? Is this the end of speakers farms?
Jan Didden
Tom2 said:
Yes, the report refers to the YSP-1
http://www.yamaha.com/yec/YSP1/idx_setup.htm
Jan Didden
Sounds like what my classmate was trying to get to work at uni for our Diploma in Acoustics and Noise Control project.
Basically it uses summed beams of HF and modulation to achieve the desired tones, e.g. two beams one at 25kHz the other at 26kHz and where they cross you get a 1kHz tone.
As all the 'work' is done at HF you only need small drive units.
Basically it uses summed beams of HF and modulation to achieve the desired tones, e.g. two beams one at 25kHz the other at 26kHz and where they cross you get a 1kHz tone.
As all the 'work' is done at HF you only need small drive units.
Is that how it works? I was more thinking on the methods used for radar beam steering. You transmit the signal from an array of transducers, and apply small phase shifts to adjacent transducers. That way you get nulls in certain directions and reinforcements in other directions.
By manipulation of the phase shifts in each matrix elements you steer the beam.
That is the mathod used by air defense and jet fighter phased arrray radars. The big advantage is that your antenna is stationary taking out a lot of potential problems with mechanical scanning and doing it all solid state.
Since it depends on heavy use of DSP's, it would be a natural technology for audio now that audio DSP's really are taking off.
But I could be wrong,
Jan Didden
By manipulation of the phase shifts in each matrix elements you steer the beam.
That is the mathod used by air defense and jet fighter phased arrray radars. The big advantage is that your antenna is stationary taking out a lot of potential problems with mechanical scanning and doing it all solid state.
Since it depends on heavy use of DSP's, it would be a natural technology for audio now that audio DSP's really are taking off.
But I could be wrong,
Jan Didden
My gut feeling is that eventually somebody will incorporate ultrasonics into osha requirements, and this technology will go away.
Not a lot is understood about long term exposure to ultrasonic acoustic energy. It has the ability to deliver significant energy levels to the eardrum as a result of it's wavelength.
Cheers, John
Not a lot is understood about long term exposure to ultrasonic acoustic energy. It has the ability to deliver significant energy levels to the eardrum as a result of it's wavelength.
Cheers, John
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