Active VS Passive crossover.

[Danieljohn]

Aaron could you elaborate by an example or something : " Mechanically-Crossovered" driver / set up?

I understand the TL box does play the acoustic crossover part.

Thanks.

Hi Yogi here are some Proofs of Mechanical & Acoustical Crossovers which are Held up by Physics & I Dont think these are Patented.

1.JBL D130 Aluminium Dome/Diaphragm is attached directly to the Voics Coil tube in order to extend high frequency range [30-17000 hz].

2.Tannoy used a Compound Horn to Acoustically Crossover at 200hz & TL is Variable Acoustical Crossover.

3.Coral BETA-10/8 Clearly mentioned Mechanical Crossover as 6000 hz & I Wish everyone publish their respective Fullrange model's Mechanical Crossover point.

Check this Link also stereonomono: Lowther PM3 Regarding Mechanical Crossover & My friends thought I'm Delusional.

Wish I was

 

[nn_in]

http://www.pteacoustics.com/linked/the case for powered speakers.pdf note from PTE acoustics

 

[DBruce]

I think active crossovers need active filters in their circuits, which means there are RC filter networks working with the amplifier circuits.
If you use RC filters in an amplifier's negative feedback loop, different frequencies will have different delays in the feedback loop, that is NOT GOOD!
I am not sure how many harmonic distortions it will generate, but different delays for different frequencies in the negative feedback loop is not a good thing for music regeneration, at least I don't like it at all.

So active crossovers might have even worse phase problems, they even generate frequency dependent harmonic distortions.

An ideal audio amplifier for me is a full linear amplifier without negative feedback loops, I guess so far only tube amplifiers can do it.

And so, a full range amplifier without RC filters will not have the negative feedback delays that is dependent on frequencies, that should guarantee the minimum harmonic distortions.

And at the driver side with a passive crossover, it will have phase shifts of course, but it's totally passive (no feedback loop and no harmonic distortions), and the driver's phase shift can be adjusted (this is the hard part and good ones will cost you). For example you can adjust the related positions of your tweeter and woofer to compensate the phase difference, or when it's over 180 degrees you can just simply reverse one of your driver's connections.

I admit I haven't listened to any active crossover systems, this is all by me an engineer's point of view only.