Acoustics 101 Course by John Dahl of THX

[Audioholics]

<P><FONT face="Arial, Helvetica, sans-serif" size=2>John Dahl has been a volunteer instructor for CEDIA for the last 11 years. So it’s a pretty good bet that virtually all of the CEDIA design and installation professionals who have passed through his classes have been taught Home Theater theory, design and calibration from the perspective of THX’s recommendations. And those THX recommendations have themselves have been distilled into practical acoustical measures for the home theater which THX has championed for the several hundred commercial theater certifications worldwide.</FONT></P>
<P><FONT face="Arial, Helvetica, sans-serif" size=2>Our own Patrick Hart monitored this class at CEDIA and took some rather detailed notes to whet your apetite and expose you to the kind of resources available at CEDIA each year. Read on for some excellent information on acoustics!</FONT></P>
<P><FONT face=Arial size=2>[Acoustics 101]</FONT></P>

 

[Rob Babcock]

Great feature. Should be required reading- you have to pass a quiz before you can post on the forums! This is the sort of material that elevates this site above the average websites.

 

[plhart]

I've found it helpful to reread and understand John Dahl's (Part 2 of the CEDIA Seminars) explanation of comb filtering axial reflections and then reading Tony Grimani's (Part 3 of the CEDIA Seminars) explanation of the same phenomena.

It is these first axial reflections, from the ceiling, floor and sidewalls which are most destructive to the soundstage, imaging and front system timbre and balance. And no built-in "room EQ" function, found in many receivers, can tell the difference between a direct signal and an axial reflection. The circuitry is simply not sophisticated enough to differentiate between signals arriving only a couple of milliseconds apart. But our ears can...

Passive equalization via acoustic treatment works.