[BobRex]

Worst being active means the amount of harmonic & phase distortions generated by active X-overs onto the complex music signals will be getting magnified by the active electronics down the audio . Getting worse & worse.

c-J

What makes you think that this is gospel?  You can contruct a single pole 6/db active filter that will have less harmonic and phase distortion than a passive filter.  Marchand makes such a crossover.  You can do the same for just about any order crossover. 

The biggest problem I see with going active is matching the levels and accommodaing any passband irregularities that the speaker vendor had handled before with a trap or such.  (think Thiel, for instance)

[JohnR]

I think what c-J is referring to there is the fact that a passive speaker crossover does its filtering after all of the electronics. So any out of band (for a given driver) electronic noise and distortion will be filtered, which is not the case for an active system. He is correct, that is a weak point of active systems.

[brj]

I think what c-J is referring to there is the fact that a passive speaker crossover does its filtering after all of the electronics. So any out of band (for a given driver) electronic noise and distortion will be filtered, which is not the case for an active system. He is correct, that is a weak point of active systems.

I agree, although usually the only additional piece of hardware between the crossover and driver in an active system is the amp.  I admit that I haven't looked at this issue specifically when researching amps, but has out-of-band noise been a big problem in well-designed amps, especially when considering the reduced frequency spectrum each amp in an active system is required to address?

And I confess that I still don't understand why a passive crossover would inherently have fewer phase issues than an active system.  Certainly I've seen passive speakers designed with a strong focus on phase linearity, but that still imposes its own compromises.

Everything is a compromise in some aspect, whether that involve design trades, end-user complexity, cost, personal preferences, or something else.  If there was a single answer, we'd be doing something more productive or enjoyable right now!

[jimdgoulding]

I'm assuming that speaker companies making active speakers are aware of this and control it somehow, but it's something hobbists should know about.  Not a hobbist myself, it's something I had no knowledge of.   

[JohnR]

I agree, although usually the only additional piece of hardware between the crossover and driver in an active system is the amp.  I admit that I haven't looked at this issue specifically when researching amps, but has out-of-band noise been a big problem in well-designed amps, especially when considering the reduced frequency spectrum each amp in an active system is required to address?

It's just a design parameter to be considered. If you have excess gain in your system (including the speaker sensitivity) and/or have a driver with a very strong resonant peak in the "hiss" region, you will have a lower S/N. And, not all DIYers have enough great amps at their disposal

Afraid I don't understand the comment about reduced spectrum - very few amps are designed specifically for a reduced spectrum (wrt 20-20k).

Phase issues - phase is just a fact of life. Linear phase digital crossovers obviously have the upper hand in that regard.

[Rick Craig]

Passive line-level filters are really a waste of time. I would do a standard passive  or DSP active filter for much more control over the performance of the speaker.

[Davey]

They're certainly not a waste to time.  If the application is straightforward enough they can make an excellent solution.  Obviously, if a person is trying to create a higher-order crossover, with possibly some dips and shelving, etc, etc, then they are not suitable.  But I certainly wouldn't dismiss them out of hand.

I see a whole bunch of silly commenting was deleted from this thread.  Good moderating.

Cheers,

Dave.

[Trismos]

They're certainly not a waste to time.  If the application is straightforward enough they can make an excellent solution.  Obviously, if a person is trying to create a higher-order crossover, with possibly some dips and shelving, etc, etc, then they are not suitable.  But I certainly wouldn't dismiss them out of hand.

I see a whole bunch of silly commenting was deleted from this thread.  Good moderating.

Cheers,

Dave.

But this too is getting somewhat of jtwrace's original question which I read as wanting to know if anyone has had experience with the same speaker using both passive cross-overs and active cross-overs. I am thinking of doing this and the whole topic is quite interesting but only some of what Rclark has said has seemed to intend to at least look into it further (and hopefully report back).

[Davey]

I doubt you'll find many/any folks who've done a comparison that wasn't apples/oranges.  You'd need to create an exact (electrical) duplicate of a reference passive filter network with an active filter.......or vice-versa.  (I hope I'm clear on what I'm saying there.)

I've done a few of these with Magnepan networks since they're fairly easy to re-create with active (or passive line-level) filters.  In that case you truly would have an apples/apples comparison since the driving voltages to the transducers would be identical (or very similar) in both cases.  Any difference heard then you could (probably) blame on the other variables.  An experiment like that would address the OP's initial question.

Cheers,

Dave.

[Rclark]

Oh don't be such a prude Davey  , it's not apples to oranges, it's framed mmg versus framed mmg, active via your preferences versus essentially an smga crossover with high end parts.

 I'm sure we could learn something useful, no? Like I said, wait until I can get the Ncores so we have a more level field.

 I think it would be fun regardless, even if nothing is gained. Hobby, right?

[medium jim]

Davey:

I've been kicking around the idea of bi-amping my Magnepan 2.5's.  As you know, i could do passive and hook directly to the ribbons.  The other option is go active and bypass everything.

What are the pro/cons.  Or should I leave them stock.   The previous owner upgraded the caps to Munford and Jantzens and possibly to 2.6 x/o specs to smooth out the bass/mid integration.

Thanks,
Jim

[Tyson]

But this too is getting somewhat of jtwrace's original question which I read as wanting to know if anyone has had experience with the same speaker using both passive cross-overs and active cross-overs. I am thinking of doing this and the whole topic is quite interesting but only some of what Rclark has said has seemed to intend to at least look into it further (and hopefully report back).

Yes, I have had that experience with 3 different speakers - the VMPS RM40's, the diy Elsinore speakers, and the GR Research V2's.  And I've used 4 different active crossovers - the miniDSP 4x10, the stock Behringer 2496, a highly modded Behringer 2496, and a DEQX HDP-3.  In every case, going active was a big step up, no contest.

[cujobob]

There are advantages to each type. Reliability of passive is a big win in my book.

[randytsuch]

Yes, I have had that experience with 3 different speakers - the VMPS RM40's, the diy Elsinore speakers, and the GR Research V2's.  And I've used 4 different active crossovers - the miniDSP 4x10, the stock Behringer 2496, a highly modded Behringer 2496, and a DEQX HDP-3.  In every case, going active was a big step up, no contest.

Which one did you keep?
I was considering the Behringer or the 4x10, leaning towards the 4x10.

Randy

[Tyson]

Which one did you keep?
I was considering the Behringer or the 4x10, leaning towards the 4x10.

Randy

4x10 is what I kept.

[brj]

Passive line-level filters are really a waste of time. I would do a standard passive  or DSP active filter for much more control over the performance of the speaker.

I definitely like a lot of what a DSP based crossover solution gives you, but in most implementations I know of, it also tends to lock you into the DAC and pre-amp solution integrated with the DSP.  The caliber or properties of those sections may or may not match one's preference and mods are your only real option if you do want something different from those sections.

(Not that it is relevant to the core of my comment, but the analog active crossovers I've explored have all had a gain stage and offered more flexibility than the few passive LL crossovers I've read about.  Then again, I've never seriously explored purely passive implementations.)

Afraid I don't understand the comment about reduced spectrum - very few amps are designed specifically for a reduced spectrum (wrt 20-20k).

Yes, I have to agree that I can't think of any amps that were specifically designed for a reduced spectrum either, but I can think of several amps than many love for their control over (sub)woofers that they wouldn't necessarily want to run full-range.

[jtwrace]

And I've used 4 different active crossovers - the miniDSP 4x10, the stock Behringer 2496, a highly modded Behringer 2496, and a DEQX HDP-3. 

Can you tell us why you chose the miniDSP over the others specifically the DEQX.

[cheap-Jack]

Hi.

(1) What makes you think that this is gospel?

(2) You can contruct a single pole 6/db active filter that will have less harmonic and phase distortion than a passive filter. 

(3) The biggest problem I see with going active is matching the levels and accommodaing any passband irregularities that the speaker vendor had handled before with a trap or such.  

(1) My very picky ears tell me so. They are my personal "gospel".

(2) Yes, I agree single pole 6dB/octave first order filter gives the lowest harmonic & PHASE distortions & it sound the BEST to my ears. BUT  passive ONLY, not active. Sorry.

FYI, my KEF 2-way bookshelves also got similar very simple 6dB first order filter passive X-over network - only 2 chokes & 1 cap !!!! But the X-over was built so cheap (like most brandname loudspeakers, regardless of price!) that I decided to rebuild it.

As I posted here before, I upgraded it by modifying the X-over to passive bi-wiring, rebuilt on a large fibreglass PC board. Also replacing the lousy tiny stock non-polar 'lytic caps with large over-rated metallized PP film aps & rewired the entire loudspeaker with heavy AWG#12 oxygen-free pure copper cables thru-out.

Knowing the 'downside' of passive bi-wiring, I moved the upgraded X-over board, out of the loudspeaker box & housed it in a plastic box (no metal please!) & seated it floating on the floor just behind the power amps.

The idea of OUTboard X-over networking is to get shortest run of loudspeaker cables from the power amp to the X-over, reducing the 'X-talking' of HF & LF along the samle cable. - the alleged 'pitfall' of passive bi-wiring or multi-wiring.
In fact, quite a few brandname loudspeakers got similar outboard X-over networking systems.

I can tell this vintage KEF loudspeakers sound so much better like nite & day after such passive bi-wiring modification. Yet it did not need to go thru the nite-mare of active bi-wiring & still sounds better.

(3) YES, you have said it - "matching the levels" different drivers is a PAIN for active X-over networking when the room acoustics kick in.

We have to understand any frequency filters get phase shifts as this is the way how a filter works - to dealy the signals to compute how the signals will behave in the immediate future. This time delay is manifested as 'phase shift'.
It is therefore our job to make sure the phase shift is minimized.

Any active networking invovles gain which can only get phase shift worse instead of limited to the amount of phase shift generated inside a passive filter as used inside a loudspeaker X-over.


c-J

[medium jim]

There are advantages to each type. Reliability of passive is a big win in my book.

The more I mull this over, the more I agree that reliability is a key factor and might be the winning ticket.

Jim

[cheap-Jack]

Hi.

The more I mull this over, the more I agree that reliability is a key factor and might be the winning ticket.

So what can be more reliable than beng PASSIVE?

FYI, I am using passive linestages for many years as they virtually generate zero harmonic & phase distortions.

I have the phonostages driving the passive linestage, driving the power amps.
My picky ears approved it along with hi-fives from my elder son, a veteran
classical pianist (by hobby) with gifted accurate pitching ears.

Hearing is believing.