Passive crossover power usage

Thanks @yodogyodog  - I have survived George Hifi, Miller, Kenjit and the swarm, so I think I can live through the bottiness.

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.

@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.

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.

  That's why I ripped the crossovers out of my speakers and use a Marchand 3-way electronic crossover and four amps to run my speakers.

So you knew the answer already and I wasted my time?

It really depends. Get a hold of XSim crossover simulator or other such device.

The big power wasters isn’t the frequency filters but the equalizer and amplitude leveling resistors.

Look at it this way. Almost all multi-way speaker systems use drivers with drivers that don’t exactly have the same sensitivity to the amp signal. That is, for the same signal a tweeter may be at 96 dB but the woofer at 88 dB.

The only way to equalize these is to "pad" the tweeter level down so it’s at the same relative output given the same amp input. That’s where the power wasting is mostly concentrated, but Zobel, notch filters, baffle step, impedance compensation, etc. can also waste power as heat. This is also why you see such large cement resistors in crossovers. 5W resistors are typical, while 25W resistors are also possible. That’s all wasted heat.  BTW, resistors are not the only place where power waste can occur, but they are the most obvious.

This is one area where active crossovers are undeniably better. Amplitude matching in the signal domain takes microwatts.