[watchnerd]

  Cool. it's not surprising after all, since any kind of waveform have a sound except if the waveform we are talking about is a flat line. But what does square waves having a sound have to do with the topic? The signal that passes through the USB cable is carrying information for your DAC, it's not connected to your headphone by any means. I mean what's the point of this video?

 
Man, if only my speakers / headphones had infinitely fast rise-time so they could reproduce square waves!

 

[spruce music]

   
Man, if only my speakers / headphones had infinitely fast rise-time so they could reproduce square waves!

What you really mean is, "Man, if only my ears had infinitely fast rise-time so they could hear reproduced square waves as square!"

 

[watchnerd]

 
What you really mean is, "Man, if only my ears had infinitely fast rise-time so they could hear reproduced square waves as square!"

 
Are you saying I don't have Golden Ears with with hearing that defies the laws of physics and biology?
 
How dare you!

 

[GuyUnder]

You guys are seriously contorting yourselves out of shape.

A square wave does not have infinitely fast rise and fall times. The difference between a 1 and a 0 is infinite, and can only exist in our imagination. We pretend that a voltage change across a given threshold inbetween slices of time is a 1 or a 0. It's a useful approximation. This just an educational statement I'm not trying to make point.

But if I was going to make a point -- it would be that we don't hear 1s and 0s. We also don't hear electrical currents. What we hear is air pressure hitting our audio reception system (ears), which includes tiny little hairs that fire signals into our brain when excited by even exceedingly minute amounts that are difficult to measure without purpose built lab equipment.

Also, why are high grade clocks great in pro audio, but snake oil for audiophiles?

 

[spruce music]

   
Are you saying I don't have Golden Ears with with hearing that defies the laws of physics and biology?
 
How dare you!

 

[spruce music]

You guys are seriously contorting yourselves out of shape.

A square wave does not have infinitely fast rise and fall times. The difference between a 1 and a 0 is infinite, and can only exist in our imagination. We pretend that a voltage change across a given threshold inbetween slices of time is a 1 or a 0. It's a useful approximation. This just an educational statement I'm not trying to make point.

But if I was going to make a point -- it would be that we don't hear 1s and 0s. We also don't hear electrical currents. What we hear is air pressure hitting our audio reception system (ears), which includes tiny little hairs that fire signals into our brain when excited by even exceedingly minute amounts that are difficult to measure without purpose built lab equipment.

Also, why are high grade clocks great in pro audio, but snake oil for audiophiles?

Clocks in pro audio are for using several different pieces of gear that must all be in synch on the clock cycles.  Otherwise drift of the various devices would make a mess of things.
 
http://www.soundonsound.com/techniques/does-your-studio-need-digital-master-clock
 
This might be educational.  External clocking increases jitter on an ADC.  Using external master clocks is not for low jitter.  It is for keeping multiple devices on the same clock signal.

 

[VNandor]

https://en.wikipedia.org/wiki/Square_wave
 
If you look up the definition part you can see that a square wave, by definition has infinitely fast rise and fall times. You can also read that it's not achievable in real systems.

 

[watchnerd]

You guys are seriously contorting yourselves out of shape.

A square wave does not have infinitely fast rise and fall times. 

 
a) We're joking
b) Yes, the perfect square wave has infinite rise and fall times
c) In the physical world, it doesn't exist
d) That's why we're joking
 
 

But if I was going to make a point -- it would be that we don't hear 1s and 0s. We also don't hear electrical currents. What we hear is air pressure hitting our audio reception system (ears), which includes tiny little hairs that fire signals into our brain when excited by even exceedingly minute amounts that are difficult to measure without purpose built lab equipment.

 
Yes, we're all aware that we hear air pressure.
 
What's your point?
 

Also, why are high grade clocks great in pro audio, but snake oil for audiophiles?

 
I do recordings and volunteer with the local symphony.  When you have to synchronize multiple ADDA devices across multiple tracks, it's a different situation from home replay.

 

[Joe Bloggs]

You guys are seriously contorting yourselves out of shape.

A square wave does not have infinitely fast rise and fall times. The difference between a 1 and a 0 is infinite, and can only exist in our imagination. We pretend that a voltage change across a given threshold inbetween slices of time is a 1 or a 0. It's a useful approximation. This just an educational statement I'm not trying to make point.

But if I was going to make a point -- it would be that we don't hear 1s and 0s. We also don't hear electrical currents. What we hear is air pressure hitting our audio reception system (ears), which includes tiny little hairs that fire signals into our brain when excited by even exceedingly minute amounts that are difficult to measure without purpose built lab equipment.

Also, why are high grade clocks great in pro audio, but snake oil for audiophiles?

OT: who's trying too hard, posting all through the night presumably on Australia / NZ time trying to convert everyone in the Sound Science forum to the ways of audio voodoo?

Anyway.

The point everyone here is making is, USB audio is a digital transmission protocol. Your square waves (imperfect they may be in the real world) are used to represent digital 1's and 0's. How good or bad these square waves look like has no bearing on the final sound unless they get so bent out of shape that a 1 gets read as a 0 and vice versa.

The only caveat to this was that "synchronous" mode USB audio devices extracted their audio clocks from these square waves, so any imperfections in this wave train resulted not in errors in the data, but in an erratic rate at which the data is read and in turn played out. Voila, jitter. Asynchronous mode USB audio eliminates this error vector: the connection effectively becomes a pure data connection, the audio data is buffered on the USB audio device and played back according to the clock on the USB device, in a way no different from a standalone music player that happens to possibly be drawing power via USB.

Finally: due to the nature of digital audio, a glitch in the transfer (reading a 0 for a 1 or vice versa) in the case of abovementioned extremely poor connection would 99% of the time result in serious glitching (consider: each audio sample is made up of at least 16 bits. The probably magnitude of error in flipping one of these bits is akin to replacing one random digit of a 16-digit number with a random number. How big / small do you think the average error would be?) or complete loss of connection (consider: bit stream consists not only of bits representing samples, but also probably error checking and protocol related info. Corruption of these would lead to stream not being recognized at all by USB device)

 

[Brooko]

You guys are seriously contorting yourselves out of shape.

A square wave does not have infinitely fast rise and fall times. The difference between a 1 and a 0 is infinite, and can only exist in our imagination. We pretend that a voltage change across a given threshold inbetween slices of time is a 1 or a 0. It's a useful approximation. This just an educational statement I'm not trying to make point.

But if I was going to make a point -- it would be that we don't hear 1s and 0s. We also don't hear electrical currents. What we hear is air pressure hitting our audio reception system (ears), which includes tiny little hairs that fire signals into our brain when excited by even exceedingly minute amounts that are difficult to measure without purpose built lab equipment.

Also, why are high grade clocks great in pro audio, but snake oil for audiophiles?

 
The bit I highlighted has to stop  - from all posters.  Comment on the matters at hand - not the people. OK.
 
Gregorio - that goes for you too.

 

[watchnerd]

There are 3 main ways that I can think of where USB can mess up digital audio:
 
1. Data loss.  If it's small enough, the error correction circuitry handles it.  If it's large, you get drop outs.
 
2. Jitter.   Not really an issue with USB itself in asynchronous systems as the DAC controls the clock unilaterally.  Any jitter asynchronous USB systems have is inside the DAC.  Takes a lot to be audible.
 
3. Noise.  Highly measurable. Might be audible if the receiving DAC is poorly isolated.  But if it measures low enough, don't worry about it.
 
 
Those are the only major ones I can think of.

 

[Argyris]

 
What you really mean is, "Man, if only my ears had infinitely fast rise-time so they could hear reproduced square waves as square!"

 
You know, if I could pick any one of my senses to upgrade, despite my enjoyment of personal audio it would not be my ears. It would be my eyes. I want to see the world the way the mantis shrimp does.

 

[U-3C]

   
You know, if I could pick any one of my senses to upgrade, despite my enjoyment of personal audio it would not be my ears. It would be my eyes. I want to see the world the way the mantis shrimp does.

​Things may get confusing very fast and your brains would be overloaded and you will never be able to appreciate human art again as everything is either messy because people splatter on things that they can't see, or everything is dull, as everyone only works within their own limited view.

 

[Joe Bloggs]

 


What you really mean is, "Man, if only my ears had infinitely fast rise-time so they could hear reproduced square waves as square!" :wink_face:

You know, if I could pick any one of my senses to upgrade, despite my enjoyment of personal audio it would not be my ears. It would be my eyes. I want to see the world the way the mantis shrimp does.

I might need an upgrade in my sense of aesthetics if I meet you sporting your new visual upgrade :blink:

 

[spruce music]

   
You know, if I could pick any one of my senses to upgrade, despite my enjoyment of personal audio it would not be my ears. It would be my eyes. I want to see the world the way the mantis shrimp does.

Me too.  But you'll need some really broadband sunglasses when outside.