[BC] Omnia.FM

[Glen Kippel]

On Mon, Oct 5, 2009 at 5:56 AM, Richard Fry <rfry at adams.net> wrote:

>
> The Fletcher-Munson curves apply to soundfield levels heard by an average
> listener in the listening environment.  That is more a function of the
> listener's audio system and its settings than to the peak/average
> modulation
> of an AM or FM transmitter.
>
> The F-M curves show that even the "loudest" AM/FM transmission will be
> peaky
> in the mid-range at SPLs from the receiver/sound system of ~90 dBa and
> less -- and ultimately that SPL is controlled by the listener.
>
> -------------------


Remember also that "loudness" is a function of the signal-to-noise ratio.
If the SNR is very good, the weaker portions of the audio are not being
masked by noise and are thus easily heard.  Distortion is just another form
of noise.  If the distortion level is high, it will mask the lower-level
portions of the audio.  Therefore, keeping distortion as low as possible
contributes to the perceived loudness.  Processing artifacts, being a form
of distortion, make excessive audio processing counter-productive.  I am
sure that David Reaves could provide more insight on this.