[sdiy] A/D Conversion Kweschunnn...

[Seb Francis]

Hi Ron,

In general always try and avoid converting backwards and forwards from analog to digital more than you have to.  A direct digital connection is almost always better.  The exception is when the digitial source and destination are different sampling frequencies - then it is _sometimes_ better to go via analog than use digital re-sampling (depending on what is doing the re-sampling).

More bits allows more detailed storage of dynamics - at high levels the difference in sound quality of 16 bit to 24 bit is not so noticeable, but at lower levels 24bits gives you more headroom (you can run input signals quieter without so much digital degradation to the sound).  When you go _digitally_ from a lower number of bits (e.g. 16) to a higher number of bits (e.g. 24) you will loose in theory no quality at all.

When you go digitally from higher number of bits to lower number of bits you loose information.  The same is true when you lower the volume of a sound in the digital domain - this is why internally most digital equipment uses higher number of bits than it's inputs (e.g. your sampler which records and stores at 16bit, but manipulates and outputs at 18bit - you didn't really gain any information, but when you turn a sample level down inside the sampler at least you don't loose information - unless you turn it down more than 2 bits worth).

Seb



Ron Malleis wrote:

> Hi all,
>
> Just wondering if anyone could give me some insight into this particular
> setup I'm pondering:
>
> Thanks!
>
> -Ron
>
> ----------------------------------------------------------------------------
> -----------------
>
>  posted October 29, 2002 09:55 AM
> ----------------------------------------------------------------------------
> ----
> Hi all,
>
> I have a Yamaha A3000 sampler that I use for samples (duh!) and outboard
> processing. A/D for the A3000 is "16-bit delta sigma type, 64 x
> oversampling". D/A (for the sampler's analogue outputs) is "18-bit, 4 x
> oversampling". Is there any weird issues, problems, quality concerns, etc.
> that I should know about if I wanted to use this for routing all of my
> analog inputs? More clearly, is it better to A/D convert @ 16 bits into the
> A3000, and then go SPDIF into the 001, or use the 24-bit converters on the
> 001, but have a A/D step (sampler in) and then a D/A step (sampler analogue
> out) BEFORE hitting the 001 converters? Kinda weird question, but I'm trying
> to get the cleanest sound possible with what I gots for now; I'm trying to
> keep the A/D and D/A conversions to a minimum, but I'm just not sure which
> way is more advantageous.
>
> Hope that my question is clear, and any replies are greatly appreciated...
>
> TIA!
> ----------------------------------------------------------------------------
> ----
> IP: Logged
>
> Ben Jenssen
> Member
> Member # 9890
>
>   posted October 29, 2002 10:45 AM
> ----------------------------------------------------------------------------
> ----
> Why dont you try it and compare?
> You will probably learn to know your equipment better too.
>
> --------------------
> Ben.
> http://home.online.no/~bjensse/
>
> ----------------------------------------------------------------------------
> ----
> IP: Logged
>
> LA_Sprawl
> Member
> Member # 18706
>
>   posted October 29, 2002 12:24 PM
> ----------------------------------------------------------------------------
> ----
> Will do...
>
> If anyone else has any insight into this, I'd love to hear it. Just curious
> as to which one (on a technical or theoretical level) SHOULD be best. Also,
> if anyone knows of any links discussing similar A/D questions/theory, that
> would be appreciated.
>
> For all I know, this could be another case of, "That's nitpicking, isn't
> it?"
>
> Thx!