Dither

Music Manic · Post by **Music Manic** » Wed Mar 08, 2006 7:24 am

Just wondering about the analogue outs of the Creamware boards D/A converters.

If you have Dithered a file,in say Cubase is it then re-dithered by Pulsar outs?

Where does dither come into play?Say I've recorded directly into VDat and don't use anything else,but SFP mixer,to analogue outs,what dither is being applied?

Thanks

ChampionSound · Post by **ChampionSound** » Wed Mar 08, 2006 2:04 pm

As far a I know, dithering is not a part of the DA conversion chain, so I believe the pulsar outs cannot just dither an audio signal by itself.

Dithering is only necessary when changing e.g. 24 bit audio to 16 bit audio. If you don't dither, you'll truncate (throw away) the last 8 bits and this doesn't sound very good. Dithering is especially useful for quiet passages/low amplitudes to "mask" the quantisation errors, which can become audible there. With the extra dither noise applied, the transitions between possible "steps" at very quiet passages seem to be more smooth this way.

Dithering has to be applied manually with a plugin (offline or realtime) or hardware (realtime) and only dither just before lowering the bitdepth of an audio chain.

So you only should use dithering at the last stage of your audio chain. Try to avoid plugins (or hardware) serially connected, which may apply dither more than once. If you can disable the dither option in the first plugins of the audio chain, please do. Otherwise you'll add extra noise, and that is something you don't want.

If I'm missing something here maybe somebody else can help me out

cheers, Darce

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[ This Message was edited by: ChampionSound on 2006-03-08 14:19 ]

Music Manic · Post by **Music Manic** » Wed Mar 08, 2006 4:11 pm

Thanks for info.So do the ASIO drivers which a project uses,or the SFP mixer outs apply dither?

symbiote · Post by **symbiote** » Wed Mar 08, 2006 5:43 pm

No. Dither is something that is added explicitely. Technically, it adds noise to the signal, so it's not something you want to do more than once. Converters and drivers don't dither, unless very explicitely mentionned.

Music Manic · Post by **Music Manic** » Wed Mar 08, 2006 7:53 pm

So it's safe to say that we need a dither plugin on the mixer outs if it is feeding our analogue outs?

If so why does some material sound really good without it?

Obviously if my project is 24bit it is truncated when it appears at analogue out?

Am I missing something?

Post by **garyb** » Wed Mar 08, 2006 8:12 pm

dither is not a nessessity. if it's not an improvement, don't use it.

symbiote · Post by **symbiote** » Wed Mar 08, 2006 9:26 pm

no you don't need a dither plugin to feed an analog out. the DAC on your scope card is 24bit and don't need dithering. most other fairly modern cards on the market also have 24bit DACs and don't need dithering.

dithering is something you add to a 24bit master when you transfer it to 16bit. it just hides the quantization noise in a sea of more pleasing noise. it's not a necessity, just a neat trick to compensate for the fact that 16bit plain fqn sucks.

edit: typo etc o<

[ This Message was edited by: symbiote on 2006-03-08 21:26 ]

ChampionSound · Post by **ChampionSound** » Thu Mar 09, 2006 4:46 am

Music Manic, Could it be that you're unintentionally using a 16-bit ASIO driver or a 16-bit wave driver to your analog outs, while playing 24-bit audio?

You never need to dither from your SFP mixer to your analog outs. Analog out doesn't mean you're going to a lower bitdepth.

IMO dithering is not really necessary with popular, hard compressed/limited music, as the effective dynamic range can be about 6-12 dB. Everything is relatively loud and there will be little quiet passages. Dithering is recommended for music with a high dynamic range like classical music.

cheers, Darce

[ This Message was edited by: ChampionSound on 2006-03-09 04:47 ]

Music Manic · Post by **Music Manic** » Thu Mar 09, 2006 7:30 am

Thanks guys