Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › Testing a DAC absolute phase ?
New Posts  All Forums:Forum Nav:

Testing a DAC absolute phase ?

post #1 of 6
2/20/11 at 5:50pm
Thread Starter 

At first sight, it'd be as simple as playing an asymmetric waveform generated in audacity (see attached one) and check with an oscilloscope the output of the DAC. Or am I missing something ?

 

 

 

Sans titre.png

Reply
post #2 of 6
2/20/11 at 6:43pm

sounds like a plan to me

Reply
post #3 of 6
2/20/11 at 6:52pm

Like many things, phase is relative.

Left phase relative to right phase.

Input phase relative to output phase.

 

Absolute phase relative to what?

 

An electric guitar has no phase.

The strings move side to side and up and down

though the speaker can only move in and out...

A kick drum could be said to have a phase...

But how do we know if they were recorded in phase or not..?

 

I think what you are getting at is the absolute phase of the recorded signal.

Your asymmetric wave form is probably the best indicator of the absolute phase.

 

Too bad I sold my scope years ago...that would be a fun experiment.

Reply
post #4 of 6
2/20/11 at 7:14pm
Thread Starter 

 

Quote:

Originally Posted by Avro_Arrow View Post

 

I think what you are getting at is the absolute phase of the recorded signal.

Your asymmetric wave form is probably the best indicator of the absolute phase.

 

Yeah, that's what I meant. It's more a way to check my wiring inside a DAC than anything else.

 

As an OT, here's an interesting link about AKG headphones being always wired out of phase: http://recording.org/pro-recording-forum/17159-akg-headphones-usually-out-absolute-phase.html

Reply
post #5 of 6
2/20/11 at 7:34pm

rmaa will tell you, for those without a scope ...

Reply
post #6 of 6
2/20/11 at 8:21pm
Quote:
Originally Posted by 00940 View Post

Yeah, that's what I meant. It's more a way to check my wiring inside a DAC than anything else.

 


Build a little stereo to mono box like this. If the outputs are wired properly a mono tone comes through loud and clear. If they are not wired properly nothing comes through.

Reply
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › Testing a DAC absolute phase ?