Active is better sounding than passive

[gnarly]

Why not go real active with motion feedback All else is scaring the barrel.

I was watching a vid of John Meyer talking about the active X-10 studio monitors they made around 2000, that had servo control on its 15" low driver.
He said one of the thing they learned about the servo control, is that it would try to counter things that it shouldn't, which made for audible disruptions.
Like if a door into the studio was opened or closed, the acoustic pressure on the cone would trigger an undesired servo reaction.

I know nothing about servo control....just thought it is interesting. .....and of the devil in the details !

 

[gnarly]

OMG not again with linear phase XOs..

Ostrich away, my man !

 

[MAB]

I was watching a vid of John Meyer talking about the active X-10 studio monitors they made around 2000, that had servo control on its 15" low driver.
He said one of the thing they learned about the servo control, is that it would try to counter things that it shouldn't, which made for audible disruptions.
Like if a door into the studio was opened or closed, the acoustic pressure on the cone would trigger an undesired servo reaction.

I know nothing about servo control....just thought it is interesting. .....and of the devil in the details !

That's interesting! Do you happen to have a link to the vid?
My simpleton understanding of servo; put an accelerometer on the driver and use the the feedback to generate a difference signal.
I never thought of the point that Meyer made. I also thought servo is interesting, and imagined about all sorts of feedback control scenarios with sensors all over the driver. My imagination and reality don't always align.

 

[MAB]

OMG not again with linear phase XOs..

Could you explain?

 

[thorvat]

My simpleton understanding of servo; put an accelerometer on the driver and use the the feedback to generate a difference signal.

Actually the system is implemented with sensing coil sending feedback the amp, not with the accelerometar on the membrane as that would cause a delay comparable to the original signal.

 

[thorvat]

Could you explain?

Nope, as if a got a 10$ bill for every time linear phase XOs have been discussed here I could easilly buy a <insert sports car of your choice here>.

 

[MAB]

Actually the system is implemented with sensing coil sending feedback the amp, not with the accelerometar on the membrane as that would cause a delay comparable to the original signal.

Thanks for the clarification. Like I said, simpleton understanding at best...

 

[MAB]

Nope, as if a got a 10$ bill for every time linear phase XOs have been discussed here I could easilly buy a <insert sports car of your choice here>.

OK. How about a Pontiac Fiero?
Edit: I'm not challenging, just wanted to know!

 

[gnarly]

That's interesting! Do you happen to have a link to the vid?
My simpleton understanding of servo; put an accelerometer on the driver and use the the feedback to generate a difference signal.
I never thought of the point that Meyer made. I also thought servo is interesting, and imagined about all sorts of feedback control scenarios with sensors all over the driver. My imagination and reality don't always align.

Lol my imagination and reality seldom align.

Found the link!

X-10 servo discussion begins around 23 min.

Fascinating meyersound history vid ...

 

[Matthias McCready]

I was watching a vid of John Meyer talking about the active X-10 studio monitors they made around 2000, that had servo control on its 15" low driver.
He said one of the thing they learned about the servo control, is that it would try to counter things that it shouldn't, which made for audible disruptions.
Like if a door into the studio was opened or closed, the acoustic pressure on the cone would trigger an undesired servo reaction.

I know nothing about servo control....just thought it is interesting. .....and of the devil in the details !

Agreed, audio is all about compromises. Which ones are we ok with?

 

[thorvat]

OK. How about a Pontiac Fiero?
Edit: I'm not challenging, just wanted to know!

Pontiac Fiero would do nicely!

Edit: Just use forum search, there should be no problem finding relevant topics/posts

 

[IPunchCholla]

So right now, the majority of votes are in the No and I Don’t know categories. The plurality goes to yes. Personally I’ve seen plenty of arguments that have convinced me that active is easier, but probably significantly more expensive. The data posted that does compare the same drivers in the same box would indicate to me that I would likely NOT be able to here a difference in music but that there would be an audible difference in test tones at particular frequencies.

Questions I have having read the thread through as someone who is at the very beginning of re-cabineting their drivers and eventually going active (maybe):
1. What is the actual delineation point for a speaker to be considered active? Is it that the drivers are constantly being monitored/modified (via active cross-overs/DSP? Or that the can be monitored/modified?
2. Are there other measurements out there of the differences in drivers in the same cabinet?
3. Is there any data out there for failure rates due to vibration? I had been planning to put plate amps in the cabinet, but now am considering DIY external.

 

[gnarly]

Questions I have having read the thread through as someone who is at the very beginning of re-cabineting their drivers and eventually going active (maybe):
1. What is the actual delineation point for a speaker to be considered active? Is it that the drivers are constantly being monitored/modified (via active cross-overs/DSP? Or that the can be monitored/modified?

A speaker is active if the crossover(s) are at line level, feeding multiple amp channels, with each amp channel going to a separate driver section.
A speaker is passive if one amp channel's high level output feeds crossover(s), that split the output to multiple drivers.

Active line level crossovers may be analog or digital. Digital may be divided into IIR or FIR. FIR may be used as either linear phase, or IIR replication (and mixed phase in more advanced implementations)

2. Are there other measurements out there of the differences in drivers in the same cabinet?

Would be nice to see more of them.

3. Is there any data out there for failure rates due to vibration? I had been planning to put plate amps in the cabinet, but now am considering DIY external.

Not that i know of.

fwiw, I'm not a fan of plate amps, but not due to reliability concerns.

I built a few speakers using miniDSP PWR-ICE250's. They were a pain in the butt to fit into a speaker where the speaker stays sealed, and the plate amp has adequate ventilation for cooling. I guess all plate amps share this problem to various degrees.
A speaker with an internal plate amp ties up the plate amp and its processing, not allowing experimentation with other DIY speaker builds.... unless of course you're willing to ditch the speaker you just built with the embedded plate amp.
Also, I've found as my measuring and processing skills have improved, my desire for more capable DSPs has grown. It's much easier to upgrade an external processor than contemplate plate amp changes. Plus I've had changing amplifier needs.

If a plate amp project is truly a 'build once and I'm done' type project...then maybe. But i think i'd still rather have external.....

 

[IPunchCholla]

A speaker is active if the crossover(s) are at line level, feeding multiple amp channels, with each amp channel going to a separate driver section.
A speaker is passive if one amp channel's high level output feeds crossover(s), that split the output to multiple drivers.

Active line level crossovers may be analog or digital. Digital may be divided into IIR or FIR. FIR may be used as either linear phase, or IIR replication (and mixed phase in more advanced implementations)



Would be nice to see more of them.


Not that i know of.

fwiw, I'm not a fan of plate amps, but not due to reliability concerns.

I built a few speakers using miniDSP PWR-ICE250's. They were a pain in the butt to fit into a speaker where the speaker stays sealed, and the plate amp has adequate ventilation for cooling. I guess all plate amps share this problem to various degrees.
A speaker with an internal plate amp ties up the plate amp and its processing, not allowing experimentation with other DIY speaker builds.... unless of course you're willing to ditch the speaker you just built with the embedded plate amp.
Also, I've found as my measuring and processing skills have improved, my desire for more capable DSPs has grown. It's much easier to upgrade an external processor than contemplate plate amp changes. Plus I've had changing amplifier needs.

If a plate amp project is truly a 'build once and I'm done' type project...then maybe. But i think i'd still rather have external.....

Thank you. That helps considerably.

Edit: Back to the CAM-cave!

 

[Matthias McCready]

Also, I've found as my measuring and processing skills have improved, my desire for more capable DSPs has grown.

Granted this again more focused at the professional product realm, sorry can't help it.

This is where I find that the separation of duties to be helpful:

1) There is an overall system DSP that controls overall tonality, addresses tuning for room and deployment, and interaction of the parts as a whole (timing, polarity).
2) Individual speaker processing: The thing that makes that particular box and drivers feel fantastic.

 

[Holmz]

...
If you ever try linear phase xovers, you're not gonna believe how much easier it is to time align two flat level lines together, than align two sloping curves !
(This is true for wavelets / tone busts too...they have less assymetric deformity around the peak with lin phase xovers)
I think this comparative ease of alignment vs IIR is a major reason why 0.02ms is achievable.
…

It is also hard to do a cross correlation of a signal when half the drivers are 180 degrees it of phase.

…
fwiw, I'm not a fan of plate amps, but not due to reliability concerns.
...

OK- so it is like your opinion or preference?
(And I do not like the colour pink)

Pontiac Fiero would do nicely!
…

I thought a sports car was mentioned?

 

[Matthias McCready]

I thought a sports car was mentioned?

That is it... you are getting a green 1990 Geo Metro.

 

[thorvat]

I thought a sports car was mentioned?

Well, as beauty is in the eyes of the beholder let's say the same about sports car perception.

 

[Holmz]

Well, as beauty is in the eyes of the beholder let's say the same about sports car perception.

Except cars have objective things like weight, cornering, braking… and maybe acceleration and power.
I seem to recall the Fiero was over 1500 kg, but it was a nice concept ~ (Mid engine, 2 seats.)

It would be interesting to compare them with older US sports cars like the early 60s Studebaker and Corvette.

https://www.hotcars.com/heres-why-the-pontiac-fiero-was-discontinued/.

But was I really was interested in the Fiero when it first came upon the scene, so I can see the attraction.

 

[Flaesh]

At the exhibition, in a 4-minute subjective test, the active LS50W sounded better than the passive LS50 . So I voted "Yes" meaning these KEFs.