AM-10HD FAQ

AM-10HD FAQ

Ten bands mean a lot of band splitting! Doesn't that cause a lot of really strange swishing artifacts?

Actually, no. Maybe back in 1975 it would (and it did!), but not now - not with our exclusive band splitting technology.

We've invented a new method to parse and recombine the audio spectrum that doesn't create the recombination artifacts that have plagued traditional band splitting methods. Our frequency bands are loosely based on the Bark frequency scale (also known as the Critical Band Rate) and our parsing method is a highly refined technique perfectly suited to a very high-resolution audio processing application.

This technique is so revolutionary that we've written an application note about it, and you can find it on the Vorsis website. Look for application note AN2008-05, “The Magic Behind the Vorsis 31 Band Limiter”. This document, while specific to the 31 band algorithm first used in the AP2000 and FM2000 processors, explains why we do high band count processing and what the benefits are when it's done correctly.

NOTE: The document referenced above has been unpublished while it's being rewritten. It will reappear shortly.

I'm confused about Emphasis and the Emphasis Location settings. What is 'Emphasis'?

The Emphasis setting pertains to the high-frequency pre-emphasis that is typically used in AM broadcasting. In the NRSC position of the control the recommended pre-emphasis according to NRSC-1 is generated. If no (pre) emphasis is used the station will sound very dull on typical receivers!

The Emphasis location selector allows the end user to place the AM pre-emphasis at the location in the processing structure that creates the sound that they desire from a sound dynamics standpoint. The three possible locations are:

Pre-MbLim:
The pre-emphasis is before the multiband limiters creating a frequency-conscious multiband limiter that constrains energy as a function of frequency - high frequencies will be limited more aggressively than mid and low frequencies. The resulting sound will be smooth and easy to listen to albeit a bit dull compared to the other settings.
Pre-Limiter:
The pre-emphasis is placed prior to the broadband lookahead limiter - if it is selected as active. This setting is recommended only for non-aggressive purist formats since broadband pre-emphasis limiting is quite audible when aggressive loudness is the goal. Note: when the lookahead limiter is not selected this setting is equivalent to the Post-Limiter setting!
Post-Limiter:
The pre-emphasis is placed after the multiband limiters and therefore high frequency peak control is achieved solely by the distortion-masked main clipper. This setting has the most open sound as far as high frequencies are concerned but is accompanied by the touchiest behavior of the Lim/Clip Drive control which sets the drive into the main clipper.

The setting of the Emphasis Location is entirely a matter of preference and taste - each has its own sound, benefits and limitations.

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