[BC] RE: DTV Audio Levels

[Kirk Harnack]

Kevin Clayborn replied with good and true observations about how we perceive
loudness.

I am adding a comment on several of his points:

> Some factors regarding apparent audio volume of commercials has a lot to
> do with the following: (from the expert, Bob Orban)
> 
> The four most important factors that correlate to the subjective
> loudness of broadcasts are these:
> 
> 1. The power of the sound.

For example, Billy Mays' powerful voice.

> 
> 2. The spectral distribution of the power. The ear's sensitivity depends
> strongly on frequency. It is most sensitive to frequencies between 2 and
> 8 kHz. Sensitivity falls off fastest below 200 Hz.

Billy Mays' voice when he's excited.  That would be throughout the commercial.

> 
> 3. Whether the power is concentrated in a wide or narrow bandwidth. For
> a given total sound power, the sound becomes louder as the power is
> spread over a larger number of critical bands (about 1/3 octave). This
> is called loudness summation.

Also referred to as the "Billy Mays Effect".

> 
> 4. Temporal integration: As its duration increases, a sound at a given
> level appears progressively louder until its duration exceeds about 200
> milliseconds, at which point no further loudness increase occurs.

Billy Mays' staccato delivery, for example.

> 
> **
> 
> And then the crux of the matter:
> 
> Regarding the loudness of commercials: There are two principal
> techniques used to make commercials louder than the surrounding program.
> The first is dynamic range compression, which increases the average
> power. The second is emphasis on frequencies to which the ear is most
> sensitive - the region between 1 and 5 kHz.

Textbook example: Billy Mays

> 
> **
> 
> All is not lost however. There are techniques that can help the
> broadcaster. 

Foremost would be to cancel Billy Mays commercials.  Vince the Sham-Wow guys is
next.

Market-by-market - yellin' car dealers.

Best - from Singapore,

Kirk Harnack