Focal SM8 user manual Level control and mute, Sweet spot adjustment, Shelving equalisation

6		ADAPTING THE SYSTEM TO
	THE LISTENING ENVIRONMENT

You will find in this section a brief description of the main features of the control software.

For further information please refer to "Focal Manager" instruction manual.

Level control and mute

Firstly, it is worth emphasizing the benefit of setting the monitoring level on the speakers themselves rather than on the mixing console: the latter case is inevitably detrimental to overall performance (due to lessened resolution in the digital domain), contrary to the former case where level adjustment takes place after the final D/A conversion.

Please note that positive values are not allowed, as 0 dB corresponds to digital full scale (maximum value).

For easy multichannel operation, the gain levels can be set both by a Master level adjustment (i.e. applying to all channels) or by an Individual level adjustment.

The same principle applies to the Mute control.

Sweet spot adjustment

Another, and very significant benefit provided by the SM8 thanks to its digital core lies in its capability to fine tune what is generally referred to as the "sweet spot".

Technically, what is it all about? Essentially it is about adjusting delays applied to each transducer so that, at the listening position, acoustic waves generated by each transducer can be perfectly coherent in phase, therefore combine together and be perceived as a virtual point source.

This requires 3 parameters to be entered by the user: spacing between Left and Right loudspeakers, distance (horizontal spacing) and height (vertical distance) between the tweeters and the listener’s ears. If a center channel is used, then the distance and height of this speaker are required too.

Shelving equalisation

This facility is ideal for gentle, fairly wide band equalisation of the bottom and top ends of the response.

The LF shelving filter is typically useful to deal with possible excessive level of LF energy resulting from acoustic coupling associated with close reflecting surfaces: mixing console, nearby walls…

The 0dB reference gives a flat response in anechoic conditions, seldom met in real-life environments.

Theory tells us that a -3dB attenuation in the bottom end should suit half-space conditions.

Generally a few -2 to -4dB’s of attenuation is therefore expected as desirable, but specific acoustic environment or other considerations might dictate other adjustments.

In the top end, shelving adjustment is more left to personal taste, or possibly to mimic the voicing typical of some specific acoustic environments or other loudspeaker systems.

The range of adjustment in amplitude of the two shelving filters is from +6 to -12dB. The frequency break points are user defined, within a range of 25 to 16000Hz.