Meridian America Meridian 518 manual DAC enhancement by using high-frequency dither

Appendix 4 –Resolution Enhancement 54

	100
	80
	60
dB spl	40
	20
				SBM
		Shape C
	0
	-20	Shape D
	10Hz	100Hz	1kHz	10kHz

Figure 6. Showing the effect on audibility of the 518's Shapes

C and D (C using pre-emphasis).

DAC enhancement by using high-frequency dither

The graphs above and in Appendix 1 (page 43) show that some of the noise-shapers produce quite a lot of supersonic noise. This high level of dither can have a very positive effect on DACs by causing them to represent each level by averaging a large a number of different levels.

This high-frequency 'lubricant' tends to smooth out truncation and linearity problems in real-world DACs.

Try the various shapes and see which one you like best in your system.

DAC or channel enhancement by word-length matching

Digital systems work best if the input data is matched to the correct wordsize for the device. Particularly where the signal has a larger wordsize than the following device, then truncation distortion will arise. The effects are real, but more subtle the other way round and are to do with jitter and linearity.

In general 518 should be set to match the input and output wordlengths to the incoming signal and following equipment. That will produce the cleanest sound.

518 User Guide