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aive

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  1. Been reading around the internets lately trying to learn about DACs, filters, up sampling, etc and came across an exact interpolation process. I.e. time domain -> FFT -> zero pad FFT -> inverse FFT resulting in up sampled time domain signal (exact interpolation values and keeping of original samples) as opposed to estimated interpolation samples based on accuracy of FIR filters. Key advantages are the process: - Keeps original samples - Exact interpolation (bit perfect?) Sound familiar? I ran some basic/simple code to confirm the maths and it seemed to work well based on random number generated waveforms. I think Schiit managed to figure out how to apply this process to audio signals and managed to do so with an embedded DSP. There are a few issues inherent to audio signals that need to be managed - e.g. periodicity, large sample sizes, etc. Additional info here: How to Interpolate in the Time-Domain by Zero-Padding in the Frequency Domain | dspGuru.com filters - Upsample data using FFTs. How is this exactly done? - Signal Processing Stack Exchange
  2. Posted this on head-fi, but thought it'd be appropriate here too I'm thinking about getting an Auralic Vega and playing back my music (100% PCM) converted and up sampled to 2xDSD (DSD128) via USB. Could people, more experienced than I in these matters, please provide some feedback re this idea? Still in planning stages of DAC purchase with sights set on Yggy but in case that option takes too long, I'm thinking about the Vega as an alternative. Started thinking about this arrangement based on information released re the PS Audio Directstream and DSD - I guess I'm trying to 'emulate'/achieve some of the features in more expensive DACs with the following: - Increasing sampling rate to push noise further into the ultrasonic band and with the use of the Mode 5 filter in the Vega (-3 dB @ 70 kHz) I should be able to preserve more original high frequency content. As an example, EMMDAC2X up samples all music to DSD128 in hardware prior to conversion. Also the Directstream LPF is apparently -3 dB @ 80 kHz (link). - Bypass the PCM-to-DSD decoder in the ES9018 chip by transcoding in the PC. There are some thoughts that the integrated PCM decoder in the ES9018 may be detrimental to sound quality. - Hopefully run the Vega in EXACT clock mode to minimise jitter. Think it'll make a difference? Thoughts?
  3. Just a quick question, sorry if this has been asked before - Is the ESS9018 chip used in the Vega capable of directly converting DSD64 and DSD128 at their native frequencies/clocks? Just wondering as I can't see support for DSD64 or DSD128 in the ESS9018 documentation (the limited brochure they have on their website) or specification of a 'max input DSD frequency limit'. I see that the max PCM input rate is ~1.5 Mhz... This is all coming about as I'm thinking of up sampling all my music to DSD128 to play through the Vega - but there's no point if the Vega doesn't process/convert it natively (i.e. if it down samples it prior to conversion). Much like how the EMMLabs DAC2X performs a DSD up sampling in hardware prior to conversion - hey if it's good enough for a 15K DAC, why not
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