Suggestions for active crossover setup please.

Thinking about putting together a second 2.1 or 2.2 system using a sub(s), two tower mains and running it with a preamp of some sort into an active crossover sending 50hz and up to an amplifier and on to the mains and letting the sub fill in the bottom. A couple questions...

1. Why isn't this setup more common? It seems like most people just send a full range signal to their mains and add a sub. The thing is, the vast majority of speakers don't do very well below 40 or 50hz so why let them and/or the amplifier struggle?

2. I have looked around a little and it seems like there a not a lot of options for active crossovers that can be used this way. Either they are made for pro audio, or they are designed for actively crossing over each individual driver or they are prohibitively expensive (as in the case of the JL Audio CR-1). So, for those who have a setup such as this, what component(s) are you using?

This is still in the planning phase so I am really open to thoughts and suggestions.

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An inexpensive example:
Rolls SX45 Stereo Two-Way Mini Crossover w/Sub Output

Isn't this what Vandersteen does? I use the M5-HP crossovers with the Vandy subs. The only thing that keeps you from using it with other subs is that the Vandy sub output compensates for the crossover attenuation.
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I've been doing a 2.1 system with active crossovers for years.  Others have been dong it since the 80s.  Main issue is that it takes a lot of work and listening to dial it in properly because the active crossover allows so much adjustment - they all do crossover frequencies, but some also do slope, Q, etc.  You can try by ear but it's better to have a mic and analyzer to confirm your settings.

FWIW, I'm using 2 First Watt B4 active crossovers.
The First Watt B4 provides an unbelievable range of settings: 6-12-18-24dB/octave (1st-2nd-3rd-4th order) filters at 25Hz to 3200Hz in 25Hz increments! And it is built with all discrete parts, no Opamps or IC's. It is about to be discontinued, so if interested act now. Reno HiFi sells it discounted.
This is a really good idea, most flexible, and has the most problems with room integration.

IT is a lot easier to integrate a bandwidth limited speaker (45 Hz and up) than a sub + satellites into a room. The lower you go, the more dragons you find.


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Hi @bob_reynolds

I'd be happy to.

I have been using satellite/subwoofer systems since Miller & Kriesel claims to have introduced the concept with the S-1B monitors and an active sub. After a lot of experimentation, and using full-range speakers and building my own I've developed a little experience in the area. :)

Here is how I see the world.

The "smaller" or more limited a speaker is, the less problems it will have with the room acoustics and room modes. This is the typical argument for super-monitors. They sound really good because they don't challenge the room acoustic problems the way larger speakers do. This is also a lot of what happens with ESL / dynamic hybrid speakers.

Getting the bottom 2 octaves (20-80 Hz) well is a real challenge. The usual solution is to add bass traps and good EQ. With a subwoofer the challenge of integrating to the satellites is also present. Doing this well almost requires you know how crossovers work as well as a speaker designer.

It is not insurmountable, but best left to a pro.

On the other hand, the BEST way to get that bottom octave (16Hz to 32 Hz) IS with a subwoofer. It has a number of advantages. You can place it independently of the satellites, you can use an in-line EQ without affecting your satellite performance, etc.

Fortunately some speakers now have really good auto-EQ features. The only auto-EQ I trust however is JL, which are not only expensive but I hear aren't very reliable. Personally I use Hsu with miniDSP and my own settings.

I always suggest, if you want good bass, start with your room acoustics first. That treatment will outlast all your speakers and gear. :) I recommend GIK for advice and products.

THEN and only then should you listen and decide what works best in your environment.


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Thanks for all the great responses. I understand that a lot of people don't use this approach because they want a simple system with as few pieces of electronics between source and speakers as possible. My first system follows that idea and I don't have any problems with it. Just want to see what an active system will sound like. Looking for very low distortion and flat response from 20 to 20. I may build my own speakers if I can't find a deal on something I like. Considering the Zaph Audio ZRT 2.5 build. Very clean from 25khz down to 60 where it starts to gradually roll off. I do have an old Martin Logan Grotto sub that has line level inputs and outputs and I was wondering if the line level outs are high passed or full range...couldn't find anything in the manual. Also need to look further into miniDSP. I just don't want raise the noise floor or introduce more distortion than I'm saving limiting the signal to the mains.
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