August 18, 2010

Which active option is right for me?

Previously I discussed the varios active crossover options. But which one is right for you?


MiniDSP is easily the cheapest option where US $125 covers a simple 2 way stereo configuration. DCX is the next step up and as this unit often can be purchased second hand, it can be very affordable. Thuneau Allocator will typically cost most, although this is highly variable depending on sound card choices, so you have some control there. DEQX is the most expensive option.

How many channels?

MiniDSP allows 2 inputs and 4 outputs, but multiple cards can be used to cater for surround systems of more complex designs. One master volume pot can control a number of boards. Given the low cost, MiniDSP boards can also be used to extend the number of channels for any of the other options. DCX has 3 inputs and 6 outputs and that will cater to most projects. 1 x 6 way, 2 x 3 way, 3 x 2 way are covered. Allocator both allow 4 channel, although if multiple sound cards are used it's possible to obtain more channels in running multiple instances of Allocator Lite. DEQX provides 8 channels.

Phase correction?

Only DEQX and Thuneau provide phase correction.

Dynamic options

DCX has a number of dynamic options that are not supported in the other options. Dynamic EQ allows the EQ settings to change with level. This means you can compensate for the insensitivity of the ears to bass at lower levels, a very handy feature. It also has limiters so you can make the system "teenager proof." You can also effectively dynamic driver protection so that bass is limited at higher output - effectively a rumble filter that only comes on at a certain level.

Ability to make quick changes

DCX wins here. It's quick and easy to tweak settings. Suppose you wanted to adjust the bass level as a particular CD or movie was bass heavy or bass shy. It's quick and easy with DCX. MiniDSP requires a PC to make any changes. I can't comment on DEQX or Thuneau.


DCX is a bit like a circus and it will annoy some. DEQX looks more hifi and with the other options you are in control.

Sound Quality

MiniDSP is a new option and I haven't tried it yet. I'm not making any assumptions here as price isn't always a good indicator of sound quality.

The sound quality of DCX is a matter for debate. It certainly won't be more transparent than DEQX, but will you actually notice a difference? There is no shortage of people who claim DCX damaged the sound quality of their system, but that could easily be explained as bias against a pro crossover which many assume to be "mid fi at best." I suggest that those who have concerns make up their own mind, ideally with some sort of blind comparison. There mere suggestion of poor sound quality is enough to sway many away from a potentially great value crossover. Don't be too easily put off. Allocator will be as good as the sound card you choose.

Balanced or unbalanced?

In most home audio systems it would be best to run unbalanced lines. Where noise rejection isn't required, balancing actually adds noise. This is acceptable in a pro application where noise pickup over 200m of cabling would be a disaster, but for home use it's rarely a requirement. In the rare situations where long runs are needed, DCX is handy. You might put a concealed audio rack some distance away where it's convenient. Otherwise, this is a black mark for DCX.

Do you want a PC in your sound system?

If so then Allocator is probably your choice. This is a good time to consider other benefits of having a PC in your sound system as a media server for audio and video playback and storage. You can save some money here and gain a lot of new features, but it all comes down to whether you like the idea of a PC in the sound system. Personal preference comes into play.


  1. Hi Paul, thanks for this great article. makes interesting digital modules, including DSP crossovers, maybe its worth looking at.

    Additional noise from balanced ouputs: This may be true for systems where the the negative output is "servo-driven", i. e. derived from the non-inverting output by an inverting OpAmp or so. But you can always "ignore" the negative ouput (and thus get rid of the additional noise) by only using the positive output and signal ground, thus yielding an unsymmetric output.

    And it doesn't cost a penny :-)


  2. Thanks for the link Ulrich, I'm about to add it to the main active options page. Always happy to hear about other options.

  3. I am from Melb., emailed you before about buying Speakers drivers, thanks for your suggestions.

    I am thinking of getting this MiniDSP even though I have a DCX2496,because I want to make my system more compact and stream the system architecture.

    I like to suggest you get a unit from MINIDSP for evaluation, I am sure you will get one, if you like it you may end buying it.

    Like your new Blog.

  4. Thanks. My plan is to use it for active surrounds, so it's only a matter of "getting around to it."

  5. I am suprised by your comments regarding balanced outputs , i have never noticed any noise issues on my system from using balanced vs unbalanced and I have not heard anyone else express that balanced outputs is undesirible for a home system. I just wish the mini-dsp had balanced outputs then I would buy a pair. Instead I will have to go with higher end soundcards to try and make a DSP computer based source/preamp, trying to get the best sound on the lowest budget.

  6. Camper, it's better in theory at least to go unbalanced unless you have a real noise problem. I have not done any proper comparisons there, it may not in reality be audible. I'd rather err on the safe side.

  7. I've been using a DCX2496 for about three years now. I had my digital sources direct into a SRC2496 where everything was upsampled to 24/96 and fed to the DCX via AES/EBU. The DCX does do phase correction, contrary to your comments above, as part of the auto-setup of the drivers. The main problem I found with the un-modded version was the tendancy for the input module to go into a 'fog' mode, as it's been described, where the sound is just awful. A reboot usually clears it, but still annoying. The other issue was the balanced output, the servos of which I believe were responsible for various thumps from the bass amp. Also, I have a tube treble amp and it works just fine. Unfortunately, another attempt at modifying the DCX wrecked a PCB last weekend so I've now ordered the miniDIGI/miniDSP kit and the 2.0 x-over plugin. If you have digital sources I really can't see any advantage of converting to analogue before the DSP. Best to keep it all digital until it goes off to the amp I reckon.

  8. @Notahappycamper: There is a balanced version of the miniDSP:

  9. Paul

    An interesting read. The big difference for the DEQX vs mini-DSP/DCX look to be the "driver correction". This feature looks to allow one to address the frequency / phase response of each driver. Have you experience with this part of the DEQX? Or it's importance?

  10. I have heard DEQX running that way a couple of times in different systems. I will be experiencing a demo soon set up to show what that part of things does. Will be interesting.


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