Graham's Blog Archive

Did I Change My Mind About Digital Audio, Or . . .

Posted by Graham
December 5th, 2013

Did I change my mind about digital audio or did I change digital audio to suit my mind?

Years ago I used to verbally trash digital audio so why am I about to launch my second DAC in the space of one year?

It’s because a few people kept saying “I wish you could do the same for digital as you’ve done for analogue”.

Shouldn’t it be that if you please people they should come to you?

But what could I do that’s different to what others have done?

Some may remember I said digital audio sounded fatiguing because of the way the analogue circuit filtered out the sampling frequencies – it filtered too steeply and the phase displacement crept down into the upper midrange. That means the musical timing isn’t quite consistent as pitch changes, and I put the fatiguing listening experience down to that.

Some designer’s use a work around which is simply not to bother filtering the sampling frequency at all. Being outside our hearing range it shouldn’t matter?

But amps can do those ultrasonics and because many operate close to the edge of stability, that sort of stimulus can get them ‘ringing’ where there is no musical signal to ‘ring’ about. The result again is unnatural, and to me, still-fatiguing.

DAC chips have oversampling filters that multiply the sampling frequency to such a degree that it can be filtered out by a less-steep filter and any designer can push the phase displacement out of the way of the audible sound. They probably do that! But there is one thing I’ve noticed that they also do – they’re all seriously concerned about great signal to noise specifications.

Well I’m not! If specmanship leads to fatiguing listening then count me out!

Analogue noise floors are ‘translucent’ not ‘opaque’ like it is in the digital domain, so trading a little noise for a more musical involving circuit isn’t going to completely block out the low end of the dynamic range.

And that’s exactly what I used to do (and still do) with my phono preamp designs – I traded a bit of noise spec for musicality.

That made the Bitzie USB DAC so incredibly musical, and the soon to be launched Majestic DAC goes further still.