I've been digging around to better understand DACs and filters and ran into some very interesting articles.

One thing that prompted me was in reading some reviews that some DACs give users a choice of filters because there are tradeoffs to each. What's interesting is Apodizing was a choice and not the one the reviewer preferred.

I always found it odd that you didn't have a choice on Meridian and is only ever used when upsampling.

This first article is rather disturbing because the Apodizing filter adds phase shifts relative to frequency. There is no free lunch. It adds phase errors on the same scale that MQA claims to fix. It references this forum and I apologize if this has been hashed out in some now closed heated debate or something. But that article was well before MQA which talks about fixing subtle phase errors which Apodizing ADDs.

Mr Apodizer Blog on issues with Apodizing filter

So how accurate is the claim above? Well here is an excellent paper for understanding the math behind these filters and does backup (IMHO) the above claim. This is an excellent paper.

Larvy Engineering Paper on FIR filters

This is Rob Watts explanation of things and is consistent with both articles above.
Upsampling always bothered me. The goal is to "up sample" to infinity (i.e. Analog).
Which is how he looks at it. By adding more and more taps he is effectively upsampling towards infinity and why he claims the more taps the better.

Rob Watts interview on his filter

I really don't care about who buys what at what price. I want to understand the science behind any of it. And know who to listen to. It's hard to know.

But I know where the science is leading me, to my current understanding.

I don't blindly follow $$$ or pounds.


- Fiddler (IMHO)

If you think listening to music is fun, try learning an instrument.
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