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Schiit Bifrost Uber Analog Upgrade - Page 42

post #616 of 1100
Quote:
Originally Posted by yblad View Post
 

 

Not to cause a huge arguement but the nyquist-shannon theory is for the absolute minimum representation of a frequency, not an accurate one. Sampling at exactly double the highest frequency turns a sine wave at that frequency into a triangular saw tooth wave of the same frequency. You need a much higher sample rate to get a realistic reproduction of the origional sound wave.

 

Just think about it, if you have a 1khz signal and you take a sample at 2khz you take one sample at the top extreme and one at the bottom. When you recontruct it that makes for a striaght line from top extreme to bottom extreme, and back again. And that's assuming that the sample is matched perfectly with the tone, if it isn't you get worse effects coming into play, that's actually the best case possible for Nyguist-Shannon. It's actually possible to completely mute the tone if the sample is aligned at 180degrees to the best case. And anything between 180 and 0 degress phase difference will give you attenuation of the amplitude. It's a lot more complicated than just you might think. 

 

Even at 4 times the tone frequency you get a very messed up wave coming out of it. Yes DACs are designed to accomodate for this as much as possible, but they do it by making educated guesses. In reality we aren't dealing with pure sine wave tones which stay locked in at a nice constant frequency where we can just round things out and hope everything will be ok.

 

 

I'm not saying they are right, just saying I wouln't discard the opinion of two experts on the basis of basic and largly approximated thoery.

 

Anyway, this isn't a discusson for this thread. There's an entire sound science section of forum for that.

Heck, I was just trying to balance the scales. I think the claim about bass makes little or no sense. Also we are not sampling at 2 kHz, so that statement isn't in context. So then, let's leave this alone and discus how wonderful the Bifrost is, My Uber USB Bifrost should be arriving on Friday. :regular_smile :

post #617 of 1100
Quote:
Originally Posted by StanD View Post
 

Heck, I was just trying to balance the scales. I think the claim about bass makes little or no sense. Also we are not sampling at 2 kHz, so that statement isn't in context. So then, let's leave this alone and discus how wonderful the Bifrost is, My Uber USB Bifrost should be arriving on Friday. :regular_smile :


It doesn't matter if it's at 2khz, 44.1khz or infinty-1 khz, it happens in exactly the same way (so long as the sample frequency is still double the wave frequency). I just chose 1 and 2 khz as nice easy example numbers because trying to imagine a 44.1khz sample on a repeated cycle placed over a 22khz signal is enough to even give me a headache!

 

But yes I fully agree it's not worth getting into here. Also, i agree that the claim very well may not be true. I was just trying to re-balance the scales after your balancing. A 200hz signal is very low frequency and I also doubt it will make a huge difference. As you said even if you take it up to a 4khz harmonic we have (at 44.1khz) 11 times the sampling frequency than the sound wave frequency. Which I imagine would put us well into the "the errors in the reconstruction from the DAC are bigger than any theoretical gains" region. I'm just saying that it's so easy to discard as simply using Nyquist-Shannon because that theorum is a little bit hopeless.

 

I don't think you'll be dissapointed, i'm really falling in love with the uberfrost rather quickly! Coming from my old Fiio e17 it's a major step up.


Edited by yblad - 2/11/14 at 7:05pm
post #618 of 1100
Quote:
Originally Posted by yblad View Post
 


It doesn't matter if it's at 2khz, 44.1khz or infinty-1 khz, it happens in exactly the same way (so long as the sample frequency is still double the wave frequency). I just chose 1 and 2 khz as nice easy example numbers because trying to imagine a 44.1khz sample on a repeated cycle placed over a 22khz signal is enough to even give me a headache!

 

But yes I fully agree it's not worth getting into here. Also, i agree that the claim very well may not be true. I was just trying to re-balance the scales after your balancing. A 200hz signal is very low frequency and I also doubt it will make a huge difference. As you said even if you take it up to a 4khz harmonic we have (at 44.1khz) 11 times the sampling frequency than the sound wave frequency. Which I imagine would put us well into the "the errors in the reconstruction from the DAC are bigger than any theoretical gains" region. I'm just saying that it's so easy to discard as simply using Nyquist-Shannon because that theorum is a little bit hopeless.

 

I don't think you'll be dissapointed, i'm really falling in love with the uberfrost rather quickly! Coming from my old Fiio e17 it's a major step up.

The last DAC I bought recently was a FiiO E18 for portable use, not bad. I'm expecting the UberFrost to be music to my ears, even though I can't hear the 22 kHz in your last example. :D

post #619 of 1100

Nothing more amusing than reading engineering debates with virtually no regard for the science human perception- of which we understand very little, I admit.

 

Anyway, my Uber is slated to arrive tomorrow, as long as nature cooperates.  I can't wait to perceive how long it takes my hippocampus, amygdala, and the rest of my audio cortex to burn-in and adjust to the sonic signature  :tongue_smile:

post #620 of 1100
Quote:
Originally Posted by swspiers View Post
 

Nothing more amusing than reading engineering debates with virtually no regard for the science human perception- of which we understand very little, I admit.

 

Anyway, my Uber is slated to arrive tomorrow, as long as nature cooperates.  I can't wait to perceive how long it takes my hippocampus, amygdala, and the rest of my audio cortex to burn-in and adjust to the sonic signature  :tongue_smile:

Are you sure you aren't referring to Human Deception? :wink_face:

Dang, I have to wait till Friday. :mad:

post #621 of 1100
Quote:
Originally Posted by StanD View Post
 

Are you sure you aren't referring to Human Deception? :wink_face:

Dang, I have to wait till Friday. :mad:


I'm chuckling too hard to argue that, even in jest.

 

Nicely played   :biggrin:

post #622 of 1100
Quote:
Originally Posted by swspiers View Post
 


I'm chuckling too hard to argue that, even in jest.

 

Nicely played   :biggrin:

I'd rather listen to my Bifrost a'play'in. :D But you're gonna get there first. I can't wait I can't wait I can't wait

You gonna get hammered by snow? I'm getting a delivery of that tomorrow night.


Edited by StanD - 2/11/14 at 7:40pm
post #623 of 1100

Upgrade now installed and Bifrost running smoothly...

 

I have an issue though. When I reconnected everything, I got no sound out at all. My first assumption was that the ug didn't work, or I'd done something wrong. I replaced the original board and still nothing. So I went into test mode...

 

Here's the setup:

 

PC with toslink > bifrost > lyr > LCD-2

 

this no longer works, but

 

DX-100 optical > bifrost > lyr > LCD-2 

 

works fine with original and uber boards

 

and 

 

PC with toslink > HiFi M8 > LCD-2

 

doesn't

 

so the issue seems to be PC.

 

Can anyone offer any suggestions, in particular what could I have done to my PC during disconnection and reconnection? or is there a fault in my logic, ie could it be something other than PC? In which case what?

 

Any thoughts welcomed...

post #624 of 1100
Quote:
Originally Posted by dc-k View Post
 

Upgrade now installed and Bifrost running smoothly...

 

I have an issue though. When I reconnected everything, I got no sound out at all. My first assumption was that the ug didn't work, or I'd done something wrong. I replaced the original board and still nothing. So I went into test mode...

 

Here's the setup:

 

PC with toslink > bifrost > lyr > LCD-2

 

this no longer works, but

 

DX-100 optical > bifrost > lyr > LCD-2 

 

works fine with original and uber boards

 

and 

 

PC with toslink > HiFi M8 > LCD-2

 

doesn't

 

so the issue seems to be PC.

 

Can anyone offer any suggestions, in particular what could I have done to my PC during disconnection and reconnection? or is there a fault in my logic, ie could it be something other than PC? In which case what?

 

Any thoughts welcomed...

Did the driver get updated? Sometimes Microsoft slips one in when they sabotage our PC with an underhanded update. Perhaps you can try uninstalling the driver and reinstalling the driver that is made just for your PC. Hopefully it isn't busted hardware.

I'll assume that you used the terms toslink and optical to mean the same thing. If possible, did you try Coax SPDIF?

post #625 of 1100
Quote:
Originally Posted by StanD View Post
 

Did the driver get updated? Sometimes Microsoft slips one in when they sabotage our PC with an underhanded update. Perhaps you can try uninstalling the driver and reinstalling the driver that is made just for your PC. Hopefully it isn't busted hardware.

I'll assume that you used the terms toslink and optical to mean the same thing. If possible, did you try Coax SPDIF?

excuse any ambiguous language, the pc audio stuff is not my area...    

 

the PC out is S/PDIF out. The cable is as below, which is what I meant by toslink...

I've used two different cables so I don't think that's likely to be the issue...

 

I'll try the driver thing...

post #626 of 1100
Quote:
Originally Posted by StanD View Post
 

Did the driver get updated? Sometimes Microsoft slips one in when they sabotage our PC with an underhanded update. Perhaps you can try uninstalling the driver and reinstalling the driver that is made just for your PC. Hopefully it isn't busted hardware.

I'll assume that you used the terms toslink and optical to mean the same thing. If possible, did you try Coax SPDIF?

the driver seems to be the original but I'm going to install the latest specific driver now

 

how easy is it to damage an optical port when removing or inserting a cable?

post #627 of 1100
Quote:
Originally Posted by StanD View Post
 

Did the driver get updated? Sometimes Microsoft slips one in when they sabotage our PC with an underhanded update. Perhaps you can try uninstalling the driver and reinstalling the driver that is made just for your PC. Hopefully it isn't busted hardware.

I'll assume that you used the terms toslink and optical to mean the same thing. If possible, did you try Coax SPDIF?

reinstalled the driver and it now works!!!  :gs1000smile:

 

thanks StanD

post #628 of 1100
Quote:
Originally Posted by yblad View Post
 

 

Not to cause a huge arguement but the nyquist-shannon theory is for the absolute minimum representation of a frequency, not an accurate one. Sampling at exactly double the highest frequency turns a sine wave at that frequency into a triangular saw tooth wave of the same frequency. You need a much higher sample rate to get a realistic reproduction of the origional sound wave.

 

Just think about it, if you have a 1khz signal and you take a sample at 2khz you take one sample at the top extreme and one at the bottom. When you reconstruct it that makes for a striaght line from top extreme to bottom extreme, and back again. And that's assuming that the sample is matched perfectly with the tone, if it isn't you get worse effects coming into play, that's actually the best case possible for Nyguist-Shannon. It's actually possible to completely mute the tone if the sample is aligned at 180degrees to the best case. And anything between 180 and 0 degress phase difference will give you attenuation of the amplitude. It's a lot more complicated than you might think. 

 

Even at 4 times the tone frequency you get a very messed up wave coming out of it. Yes DACs are designed to accomodate for this as much as possible, but they do it by making educated guesses. In reality we aren't dealing with pure sine wave tones which stay locked in at a nice constant frequency where we can just round things out and hope everything will be ok.

 

 

I'm not saying they are right, just saying I wouln't discard the opinion of two experts on the basis of basic and largly approximated thoery.

 

Anyway, this isn't a discusson for this thread. There's an entire sound science section of forum for that. While not an EE I am a mathematical physicist, so I also know a thing or two about sound waves ;)

 

Yes, this is not the right place for this discussion... love my Uber Bifrost .... but as a EE myself, I've always taken @StanD 's stance about bowing down to the almighty Nyquist theorem ... which I regard as absolutely theoretically true.  That being said, you make an excellent rebuttal regarding real world components and implementations.  

 

Of course, not being able to hear above 15khz myself, I still feel pretty secure with a sampling rate of 44.1khz.

post #629 of 1100
Quote:
Originally Posted by swspiers View Post
 

Nothing more amusing than reading engineering debates with virtually no regard for the science human perception- of which we understand very little, I admit.

 

Anyway, my Uber is slated to arrive tomorrow, as long as nature cooperates.  I can't wait to perceive how long it takes my hippocampus, amygdala, and the rest of my audio cortex to burn-in and adjust to the sonic signature  :tongue_smile:

 

Yeh, I didn't really want to escalate the situation and turn it into a firestorm. I understand the engineering half of it but I know a huge amount less about the human side, it would be ever so foolish to engage in a debate on something I'm not expert in.

Quote:
Originally Posted by BobJS View Post
 

 

Yes, this is not the right place for this discussion... love my Uber Bifrost .... but as a EE myself, I've always taken @StanD 's stance about bowing down to the almighty Nyquist theorem ... which I regard as absolutely theoretically true.  That being said, you make an excellent rebuttal regarding real world components and implementations.  

 

Of course, not being able to hear above 15khz myself, I still feel pretty secure with a sampling rate of 44.1khz.

 

To be fair for most purposes 44.1khz is probably fine. The only place it bothers me is classical music where the upper harmonics are of such a higher importance. It's made worse for me that I personally have a very high upper frequency hearing threshold, I can hear up to ~21Khz. Combination of being on the upper end of the bell curve and being in my twenties! As a physicist my mind is always more inclinded to taking a thoery and shaking it by the throat to see what falls out :evil:


Edited by yblad - 2/12/14 at 12:33pm
post #630 of 1100
Quote:
Originally Posted by dc-k View Post
 

reinstalled the driver and it now works!!!  :gs1000smile:

 

thanks StanD

Cool, I'm glad you're back in business enjoying some music.

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