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RE: How about answering a question, for a change?

"It is widely known, among those who have experience building a system using cMP recipe, that disabling Spread Spectrum, if your BIOS allows that, audibly improves sound quality. Regardless of whether it outputs via USB or a sound card."

I simply dismiss these reports as useless to me if I try them and don't notice a significant difference. The people who report these differences stop at that point and they do not go on to understand how/why these audible differences arise. In other words, they have the tinkerer mentality, not the scientific mentality. If I make my system sound better, I am not happy at this point. I want to understand why it sounded better. (Long years of experience has shown me that if I don't understand correctly what is going on it won't be long before the system reverts back to poor performance.)

I heard differences when tweaking BIOS settings when I was using a juli@ sound card. These went away when replacing the computer with a newer one and replacing the juli@ with a USB DAC. If I still heard them, I would get another DAC or experiment with various forms of USB isolation. If the USB power wire is continuous from the computer to the DAC I would start there. Also, I suspect that some of those "asynchronous" USB DACs aren't really asynchronous. The problem with software tweaking inside a computer system is that there are so many things to tweak, they all interact, and many of them change out from underneath you without your knowledge if you change something else.

As to the specifics of the spread sprectrum. I know why it was implemented, being familiar with how EMI is measured according to government standards. I don't know why changing this might affect sound quality, as this will depend on a myriad of specific details. It's easiest to see why undervolting and underclocking might improve sound quality due to lower CPU power consumption where there are problems elsewhere in the system. By the same intuitive power consumption metric, it is easy to see why inefficient linear power supplies might make things worse than a well designed switcher.


Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar


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  • RE: How about answering a question, for a change? - Tony Lauck 09/22/1411:22:54 09/22/14 (0)


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