Outboard crossover? Why not?

I didnt say all inner crossovers were bad, but that ther could be benefits of externals.  an active crossover is before the amplifier.  its called active because it needs a power supply.  the subwoofer output of a dvd player is a type of active crossover.

Erik

Inna,

I’m assuming you are discussing having a passive crossover, that is outside of the speaker cabinet, right?

There are no disadvantages at all, but several possible advantages. I should point out there’s a hybrid approach. In this, there is a separate enclosure just for the crossover components but the enclosure itself appears part of the speaker. I personally like this solution the best.

Advantages include:

• Reduced effects of microphonic interactions with the speaker or the amp
  
• More physical space is available for the crossover, allowing for the use of massive coils and caps which may not have fit otherwise
• Less space is needed for the speaker cabinet
  
• Better crossover cooling, which keeps the crossover’s behavior stable
  
• Since the heat generated by the crossover stays outside the cabinet, the temperature inside the cabinet are reduced which keeps the drivers cooler and are therefore less prone to thermal compression
  

If you were talking about active vs. passive, it’s more complicated. :)

Best,


Erik

@bombaywalla 
The Apogee's had no real speaker cabinet though, did they? :) I mean, it was one giant magnet frame.

I did not write anything about advantages of active vs. passive, by the way, at least not here. :) It's more complicated than one or the other being better. Depends on your values and needs.

My preference is a fully digital crossover feeding reference grade DAC's and a multi-channel preamp, but I can't afford that at all. :) After that it's passive.


Best,

Erik

And let's not forget open baffle designs which practically demand active crossovers. You can read lots about those on Linkwitz' site.

Erik

You have to be SURE that you have an internal crossover! :)

If so, then sure, jumper away.

The tweeter, for instance, needs at least 1 cap to keep it from blowing.

My current reference pair, there's no internal crossover at all, but you can't tell by looking at the outside.

Best,

Erik

@tatyan69

You run the risk of very easily blowing your tweeter and watching it turn ballistic unless you know what's going on for sure. There's no "less" damage here, either is as risky.

If you have a multi-meter, connect it to the tweeter section. It should, over time, read infinite resistance.

If you get a number between 3 and 10, and it doesn't change after a minute, you don't have a crossover. :)

Of course, you could just take a driver or the panel off and look.

Here is an example of an internal crossover being turned external, check out the pic with the coffee cup and caps. You'll see what I mean when I say enormous caps.

 
http://www.positive-feedback.com/Issue70/duelund.htm

Best,


Erik

Active vs. passive is not as easy as saying one is better. There's always trade offs.

Passive crossovers have no power supply noise to add, and no new op amps or transistors to put in series with your high end gear.

DSP solutions require more DAC channels.

So, I personally feel I can beat a lot of active crossovers with a passive.  Not always though. :)

Erik

@sevs great looking pics!

@tatyana69 You may have better luck on the DIYAudio forums.  Also, there you can post pics of your external crossover, which makes this discussion a lot easier.

Best,

Erik

@timlub

Thanks for the vote of confidence, I’m sure you can do a better job than I could. I still see it as trading off. For instance, if I go all DSP happy, I need to find multiple DAC’s as good as I’m listening to right now and multiple amps with an ongoing explosion of cables. Also, DSP’s tend to be bandwidth limited. Getting a DSP that can do all your tweaks at 384/32 is no mean feat. Of course, this assumes we CAN take a digital signal and DSP it. I don’t know of any libraries for doing this with DSD on the fly.

If I do this in the purely active and analog domain, I’m forced to deal with power supply noise, and the addition of even more gain stages (op amps) than there was before.

To do the same phase and amplitude matching in DSP as in passive is still a challenge, though you can iterate a lot faster. In some ways I have an easier time with passive, I can tweak the filter Q’s up or down to trade phase and amplitude issues across the drivers in funny (and very useful) ways by altering values of caps, coils and resistors.

Maybe I need to look at the DSP manuals more closely to find this.

Still, I love being able to delay the tweeter in the purely digital domain. You can do some crazy work with that. Maybe this is my alternative to half-order slopes. :)

My message is just, there’s absolutely no free lunch with any option. Integrating any two drivers in the real world is no easy feat to do well, whether it’s in a single cabinet, or a subwoofer plus main speakers.

As for off-the-shelf units, I think pro gear is designed for a very different set of expectations. Of course, some is top notch, but a lot of it is for engineers putting together megawatt systems and close-enough is all they need. Any problems with the drivers and they'll hammer it right with EQ. Gaah!! I mean, I used to do this in theaters and it was fine, especially since you have such a variation in seating position, trying to get any spot with great phase alignment was nearly impossible.

So, could I take a "generic" crossover off the shelf and get to "working" with the speakers I"m listening to now? Yeah, in minutes, but no, I could not get the same quality of alignment and integration between the drivers.


Best,


Erik