Passive crossover power usage


The last thread about crossovers (good and bad or as is and rebuilt with better components) got me thinking about the power required in watts to run it. Actually heat dissipated by the crossover itself.  Seems to me it must be minimal if some of you guys a running systems with crossovers and are using 2-5 watt flea power amps on efficient speakers.  Any ideas?  Thanks.

128x128barts

@erik_squires  pretty much covered it. The other parts that can dissipate power are inductors, particularly those wound with very thin wire like you often see in less expensive (and some pricier) speakers. 

@carlsbad2 

I agree with your point concerning "less processing is better".  The reason I went with an electronic crossover is the control I get from the ability to alter the input level to each set of speakers in the box.

I would say the biggest benefit of that is the mids and highs have no idea what the woofer is doing and they don't care.  So, everybody plays nice. 

You're right to each their own.

Regards,

barts

Barts:

IMHO, the best, simplifying solution right now for active speaker making is to use a plate amp with built in DSP. These are available from Madisound, Parts Express and miniDSP.

They come with 2 or 3 output channels. The benefits are mulitple, including not having to have 3 amps and an explosion of cables coming in and out of them, but also better frequency response tailoring than you get in an analog crossover.

I am currently working on a 3-way center channel and the features of a Hypex 3-way amp/crossover is really outstanding.

@jaytor

The other parts that can dissipate power are inductors, particularly those wound with very thin wire like you often see in less expensive (and some pricier) speakers.

 

That’s not a negative!! 🤣 The DCR (DC resistance) of an inductor can be effectively used as part of a circuit, especially a baffle-step compensation. Your average inductor has fabulous power dissipation capabilities (100W or more) so it’s a really good design choice when given a chance of using a low DCR coil and a big R or high DCR coil and no R I’ll take the latter.

So, don’t go willy-nilly reducing the DCR in a crossover unless you have measured what you are doing. In the even-ordered filter stages you would have to compensate for any missing R to ground with an additional R value.

This is where a crossover simulator like XSim or other can really help, as you can evaluate changing DCR in the frequency and impedance domain at the same time.  Small changes in even ordered filter stages can have big implications in the minimum impedance.

He then went on a tirade about crossovers and how much power they suck up.  Asked me why would I want to go back to that.

Well, it's true but usually in the home we don't care very much.  We run 10W or less most of the time. :D

It's in pro applications where power is at a premium where this becomes a big deal.