The merits of upsampling

[MLA]

Ayre's take on why apodizing, min-phase, slow roll off filters is where it's at and what they prefer. Should be the same as HQplayer's poly-sinc-shrt-mp.

https://www.ayre.com/white_papers/Ayre_MP_White_Paper.pdf

 

[Sherwood]

That was an interesting piece.  I like it because it makes me feel smart for making the choices I had previously made in ignorance.

Seriously, though, that filter sounds lovely.

[Dreadhead]

I tend to use a brickwall because that's how the music was downsampled anyway (if it wasn't it would cause aliasing) so it's recreating what's on the disc and I like that concept. That said I agree that other filters can help a lot with some of the clipping and transients in some recordings, I even made a couple custom filters myself for Foobar back in the day. The closed form filter thing seems really like marketing to me not arguing that it sounds bad or good because again it can.

[MLA]

3 hours ago, Sherwood said:

That was an interesting piece.  I like it because it makes me feel smart for making the choices I had previously made in ignorance.

Savor the moment Happens way too seldom for me...

2 hours ago, Dreadhead said:

The closed form filter thing seems really like marketing to me not arguing that it sounds bad or good because again it can.

I think it's brilliant marketing; if you're not into filter math/theory it makes the competition look like approximating amateurs .

That said, I prefer it to others for stuff recorded in something bigger than a studio booth. Good for the perception (illusion?) of space.

Edited September 8, 2016 by MLA

[Dreadhead]

The more I think about it the more I wonder if the reason we hear these filters in the "space" of the room is because those types of cues are in the lower sound levels of the signal and have started to interact with the dither which is a very wide banded noise with which the filter will interact and change the character.

When the signal clips or has some very high transient (e.g. cymbal hit) the adopodizing filters definitely sound more natural.

[MLA]

6 minutes ago, Dreadhead said:

The more I think about it the more I wonder if the reason we hear these filters in the "space" of the room is because those types of cues are in the lower sound levels of the signal and have started to interact with the dither which is a very wide banded noise with which the filter will interact and change the character.

When the signal clips or has some very high transient (e.g. cymbal hit) the adopodizing filters definitely sound more natural.

Funny, I have started to think along those lines too but was a little afraid to say it, because I don't have the filter math skills to back it up

I realized that the effect is recognizably similar across what must be very different recording rooms. I guess that makes it more of a reverb effect than anything else. If it comes from interaction with the dither as you suggest, its character would then be defined by dither type rather than recording room properties. Fascinating thought. 

 

 

[Sherwood]

HQplayer just put out an update, 3.15.  It adds a new non-apodizing filter, poly-sinc-XTR, said to be a close approximation of the filter implemented in the Chord DAVE.  It takes some horsepower to run it properly.

ROON has also announced some HQPlayer-like upsampling options built into their newest version, which should be coming out shortly.  I am positively chuffed to bits.