Hello!

I use Soundcard Deluxe to transmit aes/ebu to my DA11.
In the digital output options of my soundcard I can choose if I want
to use pre-emphasis or not.
Is there any idea to use it?, i dont know what it is.

/Krister

Basically, high frequency pre-emphasis and de-emphasis are reciprocal processes that boost the treble on "record" or before transmission, and then turn the treble back "down" to the original level on playback or reception. In a manner of speaking; it is a "poor man's noise reduction" that is based on an assumption that there is no significant amount of high frequency content in the original audio. The amount of "boost" can be in the range of 10 dB's at high frequencies.

Whereas this may be true of orchestral or vocal recordings, it certainly does not apply to most "pop" recordings! If you take a typical pop recording and apply pre-emphasis to it; the result will be clipping of any treble content that is above the (inverse of the) "boost" amount (for example treble content above -10 dB) unless the over-all level is reduced to accommodate the increase in level at treble frequencies.

Even if the level is adjusted; reducing the level of the entire recording will not add fidelity. Unless a lot of care is taken in accomplishing this digitally, it could also reduce the quality of the resulting audio. Most systems that incorporated pre-emphasis employed analog circuitry before the conversion, because the goal was to reduce the audibility of distortion caused by low-level conversion in early digital recording systems.

Because this is basically an "outmoded" process, none of Lavry Engineering's DA converters support de-emphasis. This means that if you enable the pre-emphasis it will not be de-emphasized by the DA11, and the emphasis will be clearly audible as excessive treble. In most cases, treble peaks will also be severely clipped as a result.

Brad Johnson
Lavry Engineering Technical Support