Active vs. Passive X-overs

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#41
What do you guys think: does it pay to change your passive speakers into active ones with the use of an off the shelf active crossover?
I have done the same thing with my 3-way speakers, with a Behringer cx3400. I think the sound got slightly better, but it's not a night and day difference. The greates advantage IME is that the amps are less stressed, and so I can play louder without audible compression and distortion.
Why do active crossovers still need to be specifically designed for a set combination of drivers?
 
#42
Equalization and signal processing doesn't really appeal me.
Conversions from analog to digital, back to analog...
Or do you think the only source is digital?
I have others...😀
I've heard the Tact room correction thinggie and what it did to the sound didn't convince me.
No, thanks.
I pass that one.
More jitter?:sour: [/B]
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All my sources and media are digital, so the appeal is greater for me.
You talk about more conversions, I only have one and thats digital to analogue just before the amps. Again good implementation is key.

Jitter isn't a problem with the Isochrone:

http://www.antelopeaudio.com/products_iso_ocx.html
 
#44
This is the original statement that I said was ridiculous.

soongsc said:


When you have a 1st order crossover, there is more overlap, thus when each band adds the overlap part, you get more energy. When you increase the order of the filter, there is less overlap. So even if the gain of each band is the same, the total energy over the spectrum is reduced.
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And here you agree with him.

moamps said:

Hi,
Soongsc's explanation actually does make sense. Take a look at the energy spectrum for different slopes (pic below), you'll find that the total energy decreases as the slope increases.

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That's doubly ridiculous. Now this post is way out of context so the meaning's lost. Anyway, soongsc shouldn't be posting erroneous information. And you shouldn't be agreeing with him or her. I am now going to go hang myself.
 
#45
Bill Fitzpatrick said:
This is the original statement that I said was ridiculous.



And here you agree with him.



That's doubly ridiculous. Now this post is way out of context so the meaning's lost. Anyway, soongsc shouldn't be posting erroneous information. And you shouldn't be agreeing with him or her. I am now going to go hang myself.
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Are we supposed to send flowers according to local customs?:cannotbe:

At work I'm usually proven right more than 80% of the time, so maybe you're the one that caught that 20%.

Anyway, when you do any kind of active crossover using either digital techniques or analog techniques, there is less distortion than when you try to do it in the high power section.
 
#46
soongsc said:



Are we supposed to send flowers according to local customs?:cannotbe:

At work I'm usually proven right more than 80% of the time, so maybe you're the one that caught that 20%.

Anyway, when you do any kind of active crossover using either digital techniques or analog techniques, there is less distortion than when you try to do it in the high power section.
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Flowers wilt, send cash.

80/20? Is that all?

You won't get an argument from me.
 
#47
carlosfm said:


Another active stage on my system?
No way.
Don't play with the signal, it is too sensitive.

Otherwise, another active stage in the way of the signal can only make things worse.
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A passive filter adds far more distortion and phase anomalies than an active stage. I'm not sure about your logic that passive is better, although you do make some great points about matching drivers first!

But as long as you're happy with the result, that's all that matters. Personally, I'll never go back to passive.

Az
 
#48
I think my post #42 may have been missed because shinOBI posted only 2 mins after me.. Here I'll repeat it:

What do you guys think: does it pay to change your passive speakers into active ones with the use of an off the shelf active crossover?
I have done the same thing with my 3-way speakers, with a Behringer cx3400. I think the sound got slightly better, but it's not a night and day difference. The greates advantage IME is that the amps are less stressed, and so I can play louder without audible compression and distortion.
Why do active crossovers still need to be specifically designed for a set combination of drivers?
 
#50
keyser said:
Why do active crossovers still need to be specifically designed for a set combination of drivers?
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Because quite often you want to use driver roll off as part of the crossover, and active, just like passive, need to be designed for this.

For instance, suppose you need a 12dB/octave total roll off for a mid/low crossover. The mid driver has a 6dB roll off starting at 100Hz, where you want to crossover. For this, you would then only need a 6dB crossover response to get the total of 12dB that the system requires.
 
#52
You might be making it simpler, if you take the example shown above. 😉

Whilst I'm not a total minimalist when it comes to component use, if you can lose a couple of op-amp stages in the crossover, why not? Even if you use a premade pcb you can just bypass the stages not required.
 
#53
still I wonder why would you go through the fuss of making the crossover more complicated if there are better matching units available. two units that are both flat at the crossover point.
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If you want to neglect the drivers' response(s) when calcualting an active x-over they must be flat faaaaaaaaaaaaaar beyond the crossover frequency.

Regards

Charles
 
#58
pinkmouse said:
Digital purely has the advantage of steeper slopes that are easier to impliment.
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There's more to them than that.

You can tailor the rolloff perfectly to get an exact acoustical rolloff of your choosing and very easily. Whilst this is possible with passive and analogue active XO's be prepared for quite a number of hours testing.

Your also have access to phase perfect filters such as FIR with digital, passive phase accuracy is laughable compared to these.

I too always overlooked digital XO's up until a few weeks ago, dissmissing as them as complicated and harder to get good results from compared to passive. Now I'm so convinced by the improvements that I'd have a hard time going back! That's when you know something is right.

The most effective option is a PC equipped with a pro level audio card such as an Creamware, RME, Lynx etc. And an ASIO 2.0 compatible plugin host such as Console. Then you need the actual filter and DRC plug-ins, Waves Linear Phase EQ is an FIR filter and is quite exceptional. Voxengo CurveEQ - another FIR filter which is phase perfect, will equalise your room response using a captured impulse response that you create using a mic at the listening position, the program then uses an inverse of this signal to process the audio and fully eliminate your room 🙂
 
#60
carlosfm said:
Inserting passive line-level components between the pre and the power amp(s) is not a thing I would do, only if they were inserted inside the power amp, as part of the input stage.
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That's definitely the way to go. Replace the cap in the input stage with a cap that allows the same rolloff as the tweeter cap. Use the amp's input impedance to set the level correctly for the tweeter circuit. Now you have picofarads instead of microfarads, and no resistor instead of a 10 or 20W power resistor, sucking the life out of your tweeter.

Active filters are good in some situations, with multi-way speakers, with complex crossovers.
For subwoofers it's what I use, and in this case it's obviously better.I
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I agree that the Epos and other minimalist designs don't necessarily need an active filter. But for those rare situations a passive line-level filter is clearly better than a speaker-level XO. And especially when the speaker XO has an inductor in the woofer cct
 
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