Upsampling..........

Funny you should ask about the algorithm. I was thinking about this last night (because I really have no life !)

A perfect CD player would have an anti-aliasing filter that was a perfect brick wall. Below 22kHz signals would be completely untouched, and above 22kHz would be infinite attenuation.

In the time domain this equates to a sin(x)/x impulse response.

So my guess is that a good place to start for the interpolation algorithm would be the sin(x)/x waveform.

" Funny you should ask about the algorithm. I was thinking about this last night (because I really have no life !)"

Thanks for the laugh Sean...that was funny in an Audiophile sort of way, my wife didn't get it though.

Dave

I'm not sure of the science, but it works. I believe that Seandtaylor99 above does a commendable job of an explanation. I recently installed an upsampler on a CD player (AH! 4000) that I was already familiar with and pleased with. The change was dramatic, though it's been taking a while to break in.

-Darren

Hi Dave,
my wife would get it because we're both engineers ! In fact we often have nerd type conversations regarding audio, even though she's not interested in hifi, and she calls me a geek whenever I tinker with my system.

By the way I've never known the difference between upsampling and oversampling .... I suspect that they may be the same thing, but that the marketroids decided that upsampling is a more marketable term.

As an engineer I must say .... "Damn those marketroids !".

See Goldy! Not a stupid question after all. The current top of the line Zanden Dac/transport retails for $43,440.00. It doesn't up sample or over sample. Straight red-book only. Seantaylor99 mentions a filter and brick wall. The Zanden claimes better sound with out this filter and brick wall.
It's all above my head. I just listen to what sounds best to me in my price range and go for it.