Hybrid Audio Technologies Legatia Pro - Manual (Page 34)

Legatia Pro User’s Manual ©Hybrid Audio Technologies Page 34 of 43
• ITD is the dominant factor for frequencies below about 500 Hz;
• A combination of ITD and IID are dominant for frequencies between approximately 500 Hz and
2,000 Hz; and
• IID, in concert with HRTF, are dominant above about 2,000 Hz.
These are generalizations, and are subject to the size and shape of one’s head and torso, and size
and shape of the outer ear (the folds and ridges of the ear), but in general, the above is a good
guideline for establishing ITD, IID and HRTF thresholds for the human auditory system.
Because the Legatia Pro midrange’s ability to play into the sub-400 Hz range, an effect clearly
dominated by ITD, up to and including frequencies exceeding 6,000 Hz, an effect clearly dominated
by IID and HRTF, placement of this driver is extremely important. The driver should be placed as far
forward as possible in the vehicle to optimize ITD. Lateral (forward to back) placement is much more
important than horizontal placement (up and down). This is because of the brain’s ability to process
sounds such as spectral envelope cues, and use a phenomenon known as the “precedence effect”;
the brain can be easily “fooled” into thinking a sound stage is high with kick panel or floor-mounted
speakers (a word to the wise: the best place to put a set of speakers is not always “up high”, as most
vehicles do not offer an amicable location in the dashboard or a-pillars for good image placement for
both seated passengers, especially in the critical frequencies sub-500 Hz). In addition to the time
equalized placement of the drivers, the end-user must also consider that above approximately 2,000
Hz, intensity plays a key role in good sound staging and imaging. Therefore, the Legatia Pro
midrange’s should be placed in an area where intensity differences can be equalized, either
mechanically or electronically, to ensure good imaging and sound staging.
The lesson to be learned is that, like Lesson Two, the Legatia Pro midrange should be placed as far
forward from your listening position as possible, and every effort should be made to optimize time and
intensity domain characteristics of the installation.
Lesson Four: Point-Sourcing
The term “point-sourcing” is often used to describe the technique of having a single pair of speakers
in an installation cover the majority of the critical middle band frequencies. In many installation
scenarios, the Legatia Pro midrange could be considered a point-source speaker driver, because it
has the ability to reproduce up to six octaves of tones. Point-sourcing, if done correctly, can lend itself
to a variety of valuable attributes, including precise image definition and stable sound staging
character. By applying Lessons 1-3 above, the Legatia Pro midrange can be used as a point-source
driver to achieve excellent staging and imaging results.
The lesson to be learned here is that the Legatia Pro midrange, given its wide-bandwidth design, can
faithfully reproduce as much as six octaves of tones, and would make a valuable addition to any
sound system as a point-source driver for the spectrum comprising vocal imaging cues.
Lesson Five: Reference
One of the most important things to do before completing your Legatia Pro installation is to get a
reference for your future listening tests. To really know what a snare drum sounds like, you must go