16x Custom Filters

[manisandher]

Hey Peter, I've been playing around with the 16x filters in my office system. The Mid filter seems 'off'. What I mean is that I can hear some similarity, or 'house sound' between the Low and the two High filters, but Mid just seems so different - much duller/softer than the other three. Looking at the specs there doesn't seem to be a lot of difference between  the Low and Mid, but they sound very different. (Maybe because of the number of poles perhaps?)

Anyway, just let me know if everything is actually in order, and as you would expect.

Mani.

[PeterSt]

Hi Mani,

Well, each of the filters is "build up" in a different fashion (like the umber of poles you mention) so it can easily be that. And if the other 3 have a similar sound, then it is coincidence when that would be because of the build up. Of course I see you looking at the 2x 17 for the Low and the first High above, but ... ok, maybe.

My explanation would be a very different one :

I use the Low because there's more "high" in it. This could be hard to explain, but when the high frequency sines are better shaped, they will audibly express more highs to your ears and it is genuine. Remember that this is at the cost of the even higher frequencies we are not suposed to hear very welll anyway (like 16KHz in this case) ...

The High filters approach it the other way around;
They exhibit the most of the highest frequency but now at the cost of THD. The effect ? more highs again.

So yep. But this time because of the sines out there being too much of a square, so to speak (they are not nice sines because of the implied distortion).
Maybe it is not 100% justified, but squares are more "high frequency"; the "not justified" springs from a kind of chicken egg problem, because a "square" in the music first implies high frequency (a square is build from many high frequency sines), which goes odd because the high frequency sines required, which become square - and those ... etc.

Anyway, the High filters too implies high frequency but that is false.

Lastly, I should add that I use Low from pure theory - I like more highs. So once in a while it is really so that I engage Mid to get rid of too much highs, for the situation of concern. That this next helps is because my theory is right, or that you are right that something is odd or different with Mid. But as long as my theory is there, I like to stick to that ?


Peter

[manisandher]

Thanks Peter, that makes sense. FWIW, I too have a strong preference for Low but sometimes (very rarely) engage Mid if I think there's too much HF grunge (for example with that other DAC I had here recently).

Isn't it interesting that an earlier roll-off can make the sound 'brighter', just because of lower distortion in HF that you can hear!!! So if hires really does sound better, it's nothing to do with the extended frequency range - more likely better phase and timing (pure speculation, because to my ears redbook can sound absolutely fine).

Fascinating stuff!

Mani.