passive crossover and active analog line crossover.

[arivel]

Hi everyone . can you explain something to me please?
Vorrei sapere quali sono le funzioni che un crossover passivo non può svolgere e quali quelle che il crossover di linea analogico attivo non può svolgere. infine un confronto tra le due tipologie .
bye thank you

Translated:

I would like to know which are the functions that a passive crossover cannot perform and which are the ones that the active analog line crossover cannot perform. finally a comparison between the two types.

 

[tvrgeek]

Sorry, I do not how to translate from I assume Spanish? A full page Google will translate, but not a message.

 

[MakeMineVinyl]

A passive crossover is more limited in its ability to do equalization corrections to compensate for driver responses, and wastes some degree of signal in the process of doing so. EQ is possible, but not with the precision of an active.

The only negative with active crossovers is that it is a whole lot more trouble and requires more knowledge to implement correctly.

 

[arivel]

excuse me .
I tried to correct by clicking on the "edit" button but it won't let me

 

[arivel]

A passive crossover is more limited in its ability to do equalization corrections to compensate for driver responses, and wastes some degree of signal in the process of doing so. EQ is possible, but not with the precision of an active.

The only negative with active crossovers is that it is a whole lot more trouble and requires more knowledge to implement correctly.

but what do you mean by equalization?.
a flat response at all frequencies or SPL corrections which may be different depending on the frequency and the environment?

 

[MakeMineVinyl]

but what do you mean by equalization?.
a flat response at all frequencies or SPL corrections which may be different depending on the frequency and the environment?

Drivers are not perfectly flat, and speaker manufacturers routinely 'voice' their speakers to sound a particular way - equalization does this. This is traditionally done in the crossover network in the speaker.

In an active crossover, you need to establish these corrective equalizations. Equalization to correct for room problems is an entirely different topic. Also active speakers which have built-in amplifiers and DSP equalization are something altogether different.

 

[arivel]

The only negative with active crossovers is that it is a whole lot more trouble and requires more knowledge to implement correctly.

do you mean DIY or commercial ones ?

 

[MakeMineVinyl]

do you mean DIY or commercial ones ?

Both. You need to invest in multiple power amplifiers, match the outputs of the individual drivers, and EQ for flattest room response and/or to taste. A passive speaker you just hook up the power amplifier, move the speakers to the ideal position and you're done.

 

[DVDdoug]

Once you have an active circuit you can make filters with very-sharp cut-off at very little additional expense. With passive crossovers you have to add proportionally more components and the large capacitors & inductors cost more than the "small" capacitors & resistors used in active crossovers.\

Of course, the disadvantage of active crossovers is the extra cost & complexity of the additional amplifiers. And with active speakers you have to supply power to the speakers.

And since there will be amplification anyway, with active crossovers you can boost or cut the signal to the drivers individually. With passive crossovers you can only attenuate. With active crossovers it also doesn't take much additional circuitry to add some equalization to fix a dip or bump in the frequency response or to extend the low frequencies.

Digital processing is similar... It's more expensive to "get started" than with an analog crossover (or equalizer) but once you have the processor and A/D & D/A converters it costs nothing to add more-complex or more-advanced software (although you do have to have adequate processing power).

 

[tvrgeek]

A passive crossover is more limited in its ability to do equalization corrections to compensate for driver responses, and wastes some degree of signal in the process of doing so. EQ is possible, but not with the precision of an active.

The only negative with active crossovers is that it is a whole lot more trouble and requires more knowledge to implement correctly.

I would say different, not harder. Actually much easier in my view, but I have been doing passives for 40 years. Active means more parts, as in more amplifiers and the crossover system. More money for sure.

 

[MakeMineVinyl]

I would say different, not harder. Actually much easier in my view, but I have been doing passives for 40 years. Active means more parts, as in more amplifiers and the crossover system. More money for sure.

A state variable filter is a bit more complicated to implement in a passive crossover.

 

[tvrgeek]

Yes it is. That is why I said active can be easier. Plus, you can play with active by a keyboard rather than a soldering iron. All pass is a pain in the backside in passive. A HP for the woofer to control it sub Fs means HUGE parts, where active is a line of code.

 

[arivel]

is a preamp essential?

 

[tvrgeek]

I am not sure I know the exact context of your question. so let me make a complicated answer

IMHO, the volume control needs to be buffered to drive a power amplifier. Passive volume controls, depending on the amplifier input impedance, can cause far more distortion that a good buffer stage. The "less must be better" is good logic, but fails when you understand amplifier input stages.

So, if your DAC or whatever source has a decent line drive output, like the Topping D30pro, you do not need a separate preamplifier. It is built in.

If it does not have a volume control, you need one so a preamp is needed. A volume control in software before the DAC reduces fidelity.

But, you may want a headphone amp too, so something like the JDS Atom Amp is a great little box.

Same thing if your DAC or source feeds something like a DBX active crossover, it has sufficient buffer to drive a power amp and has a buffered volume control. A simpler active crossover, like the Rolls, does not have a master volume so it has to be fed by a preamp with a volume control.

In other words, your volume control needs to be buffered with a line driver to feed your amplifier. If you are feeding an integrated amp, of course that is built in.

 

[Trdat]

I have the Marchand XM66 and always wondered how much better it will be compared to a passive crossover of course with decent implementation and DSP. But the below average results from the XM44 made me suspicious.

My understanding is that an active analogue crossover implemented correctly beats a passive while a digital active surpasses analogue active but I have heard counter arguments for all.

 

[tvrgeek]

I believe none are perfect. All have positives, all have negatives
We can build very predictable analog active filters. Easy. But our drivers do not behave that linearly.
In passive, we can play a lot with phase, bumps, notches etc. Harder for time.
In DSP we can do all that, but run the risks of degrading the resolution if we cut in DSP and then amplify in analog.
DSP gives many more ways to screw up.
Which crossover depends. Mains to sub, not too critical but at 3000? different details.
I am considering a hybrid on my next build. Analog active but passive networks to fix problems in the speaker. Tweeter roll-off etc. We could do these in a dedicated analog, but the complexity skyrockets. I am not quite ready to go MiniDsp.

 

[sailor2005]

Sorry, I do not how to translate from I assume Spanish? A full page Google will translate, but not a message.

It's Italian

 

[arivel]

besides the state variable which seems to be the simplest what other configurations are possible?