Hey everyone, I’ve been trying hard to suppress my curiosity because it’s like opening a whole new can of worms (similar to my previous post about cables). But I can’t hold back any longer - and maybe I like to open new cans of worms from time to time? - so I have to ask: Do you always stick with the default filter on your DACs, or do you have a preferred filter that you switch to whenever possible?
I know some people believe that filters are “invisible,” but in my experience, that’s not the case. For instance, when it comes to Linear Phase Filters, I’ve noticed a significant difference between the Fast and Slow options. The same applies when comparing Minimum Phase filters to Linear Phase ones. Despite the common understanding that filters only affect frequencies above 20 kHz (except for Slow Filters, which gradually drop within the audible range), my ears tell me otherwise. Why would I perceive differences if they were limited to the “inaudible” range?
What stands out most to me is how filters impact the “attack” and “decay”. Linear phase Slow filters offer a gentler attack and an airier presentation, while Linear Phase Fast Filters are sharper and quicker in both attack and decay, resulting in a cleaner but less airy sound. As for Minimum Phase Filters, they share the same characteristics I mentioned earlier for their Slow and Fast iterations, but compared to Linear Phase one their attack tends to be sharper and cleaner. However, their decay is generally slower—slower even than Linear Phase Slow Filters—leading to a more organic and richer overall sound. These are just a few of the distinctions I’ve observed. I decided to not go more in depth in this post because there are way too many in between Filters (Low ripple, Hybrid, Apodizing, etc.) and the post would end up being unnecessarily detailed and longer than it needs to be.
Now, to answer my own question: I tend to stick with the default filter on my DACs most of the time. After all, there must be a reason why the manufacturer chose a particular filter as the default. However, I also enjoy exploring different ones to take advantage of all the possibilities my DAC offers. Lately, I’ve been using mainly the Hybrid filter on my BTR15 and the Minimum Phase Fast filter on my KA17 (both default). Occasionally, I’d like to change them and use filters that I think better suit a particular IEM. For example, when I want to add a little more clarity to warmer-sounding IEMs, I switch to the Linear Phase Fast filter (or a variant of it). Alternatively, if the treble on an IEM is borderline too bright, I opt for a slow filter (either Linear Phase Slow or Minimal Phase Slow).
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