December 5, 2010

Active crossover listening tests - conclusion

The process of evaluating active crossover units has been revealing. My findings briefly are:

1. Instant switching is critical for evaluating subtle differences.

2. Digital active crossovers may not be compatible with tube preamps. Some attention is needed regarding gain structuring.

3. The units were comparable regardless of price - the differences could be picked by some and not others. This would suggest they are quite subtle. (Note - we did not adequately test DEQX so it is excluded from that comment).

4. All the units were transparent enough to satisfy the majority of DIY speaker enthusiasts.

Tube systems

If you have tube preamps and power amps, then you may have trouble with any of these DSP units. You could use MiniDSP as a development tool and then have an analogue crossover made up. Or you might find a solid state preamp gives better results. 

Sonics vs features

In a test like this, attempts are made to level the playing field. In an actual system, they will all sound different as they have different filtering options. DEQX allows steep filters up to 300db/octave as well as advanced time and phase alignment options. DCX only allows textbook filters while MiniDSP allows advanced custom biquad filters. The modded DCX has a remote control. DCX has an auto align feature for time alignment, while with MiniDSP this can be done manually. 

In general I would tend to recommend MiniDSP as the first low cost option to try. 

More about DCX vs MiniDSP >


  1. Paul, thank you for the great report and findings. I could see that you guys are very much analog oriented. I think that you should next time run test where only digital out from CD is sent to digital input of the various DSPs. In my opinion, unless you are running analog source, such as turntable or reel to reel, it really is disadvantage to have all these unnecessary elements in the signal path. First DA conversion in CD, than analog out of CD, than analog tube (or solid state) preamp with its own degradations, and than AD conversion in front of DSP. I am positive that is the reason you guys did not find much differences between the units.Your tube preamp sound great on its own but when it passes through opamps or electrolythic cap plus opamp used in Behringer there is very little beauty left in your signal.

    Regardless, it was great fun reading your report. I could understand you guys were exhausted at the end of the day, since doing this careful listening tests do tire you easily.
    All the best and thank you for publishing results of your tests.
    AR2 from DIYAudio

  2. Why might tube preamps and/ or power amps, give trouble?


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