I did not keep it. (Noise wasn't necessarily awful, but there was a subjectively apparent increase in noise output at the speaker when introducing the K231 to the system. At listening distances, it was inaudible; however, the increase at the speaker was significantly higher than what I have experienced when swapping other components, and that, combined with the fact that it was noticeably louder in one channel than the other, left me unsatisfied.)
I am currently using an SPL Crossover (I didn't, and wouldn't, pay MSRP). I don't have any complaints with the unit, but I am not sure it is an end-game solution for me.
Pros:
- It has some nice features, like 360 deg of phase control and level-adjustable VU meters which can be set to show total / low / hi signals (I have it set to show the hi output so that I can tell when I am pushing my amps towards clipping).
- SPL claims 138 dB of dynamic range, but it appears this is at max input / output of +32.5 dB, which as I understand it is approx. 11v RMS and well beyond any signal I might introduce to it (current digital source is a Topping D90). At ~4v input, my math shows it should give approx. 118 dB of dynamic range based on the published specs. Amir recently measured one of SPL's HPAs (Phonitor line), and the preamp section (rated for 135 dB of dynamic range, again at +32.5 dB) measured 112 dB of dynamic range at 4v (which if we adjust for the crossover's +3 dB of DR, puts us around 115, close to the 118 estimate).
Basically, you'll likely never drive the crossover to clip, and it might pair nicely with a low gain Benchmark or Purifi, but you need a source with sufficient output to take advantage of it. (RME ADI-2, maybe?)
Cons:
- Crosstalk is awful - published specs state ~75 dB down at 1k, similar to the specs listed for the Phonitor HPA Amir measured; his measurements showed that by 20k crosstalk was only 60dB down. I am assuming the crossover would show similar.
I'm happy with the utility of the crossover, and I have no complaints re: distortion, etc., but I question whether there is any value in having 115-130 dB of dynamic range if crosstalk is only down 60-70 dB. Might I actually get better total performance out of a different unit with less dynamic range (or input headroom) and better crosstalk + functionality?
Unfortunately, there do not seem to be many options available that are all-in-one, so-to-speak. MiniDSP SHD comes to mind, but the SINAD / DR isn't up to par with new DACs or Purifi / Ncore / Benchmark amps. Audiolense + a couple high-performance DACs might be best, but I believe you need a PC involved for that.