Active vs Passive Monitors

[jodaki]

Hi,
I was asking for hi-fi advice on a well known hi-fi forum and encountered a very widely prevailing view that passive speakers are superior to active systems. In some opinions, vastly superior.
I'm not sure but I think the belief is partly about the benefit of a separate power amp - that a dedicated/separate power amp will be 'cleaner' or anyway do a better job than an integrated amp, possibly also the physical distance/separation from the cones being a consideration.

Do people here feel it's true that passive systems are better than active ones? And does this apply to studio monitors as well?

thanks, John

[MOF]

If the crossover and separate amplifiers are high quality then they should be better than the single amplifier and passive crossover especially at high volume, well that’s what I read ages ago.
I seem to remember that the active crossover is more accurate at its crossover point.

[jodaki]

If the crossover and separate amplifiers are high quality then they should be better than the single amplifier and passive crossover especially at high volume, well that’s what I read ages ago.
I seem to remember that the active crossover is more accurate at its crossover point.

Sorry to be uninformed, Im not sure what you are saying.

My question is asking about the comparison between preamp signals going via cable to a power amp and then via cable to some passive speakers vs a hifi system with preamp signals going via cable then into active speakers.

Are you saying the relevant audio quality difference (if there is one) between these systems is down to the crossovers?

[Hugh Robjohns]

I was asking for hi-fi advice on a well known hi-fi forum and encountered a very widely prevailing view that passive speakers are superior to active systems. In some opinions, vastly superior.

Ah... you're entering a mystical world where ignorant opinion trumps science and facts...

The vast majority of mastering suites and recording studios use high quality active monitoring, for very good scientific reasons... and have done for decades.

I'm not sure but I think the belief is partly about the benefit of a separate power amp - that a dedicated/separate power amp will be 'cleaner' or anyway do a better job than an integrated amp, possibly also the physical distance/separation from the cones being a consideration.

The last point is pure make-believe. A good quality amp will always trounce a cheap amp... and some budget active speakers use cheap amps.

So yeah, a decent passive speaker with a very good amp may well perform better than a cheap active speaker with cheap 'chip' amps.

However, there are serious compromises involved in passive crossovers and long speaker cables that are completely overcome by active designs.

So a good active design with good amplifiers and a low-level active crossover will easily outperform any passive speaker in terms of distortion, transients, control, linearity, and any other parameter you care to mention. Throw in some good DSP and you can improve performance way beyond anything a passive speaker can do.

Do people here feel it's true that passive systems are better than active ones?

You have to put some boundaries on that. As I said, a very good passive may well be better than a cheap active. But a good, professional active system will blow passives out the water every time.

And does this apply to studio monitors as well?

Absolutely — because accuracy and fidelity is paramount, as opposed to hi-fi land where the emphasis is on flattering, impressive and nice.

ATC and PMC are two British speaker manufacturers who both supply the hi-fi and studio markets. Both offer passive and active models, but the top-end models are all actives using high-quality amps.

[Hugh Robjohns]

Are you saying the relevant audio quality difference (if there is one) between these systems is down to the crossovers?

It's much more than that.

Low-level active crossovers are far more accurate in terms of frequency and phase responses, and allow much steeper slopes that improve the drive unit integration.

And by driving each speaker drive unit from its own amp intermodulation is removed and cone control (starting and stopping movement) dramatically improved.

It's also possible to engineer much better driver protection systems, and — with dsp — correct mechanical imperfections in individual drivers.

[Nazard]

If you read FAQ number 8, from ATC, it explains some of the issues:

https://atc.audio/faqs/

[Arpangel]

There is a tendency in the hi-fi world to put down any modern ideas, or changes in the way we listen, traditionally domestic hi-fi used a separate amp and speakers, I'm not saying active is anything new, but its not normally used in hi-fi systems, also, it does away with the separate amplifier, denying the hi-fi enthusiasts something else to play with and get obsessive about.
In short, it's actives all the way for me, especially in the studio, no speaker cables, separate amp's to worry about, and all the hassle that goes with these thing’s.

[ajay_m]

An active monitor will have an amplifier for each driver; two in most cases, more in some of the higher-end monitors that have dedicated midrange drivers as well as woofers and tweeters,

Because the signal can be bandwidth split using high gain opamps rather than a passive crossover made from inductors and capacitors, it's possible to design this bandpass filtering to have steeper crossover points and have more controllable phase shift at the crossover point, then any passive circuit could ever achieve.

Active monitors can also support relatively sophisticated digital signal processing which can be used to compensate (to an extent) for room acoustics, evening out the frequency response, for example, to compensate for room nodes caused by reflection. This is possible with passive designs but very uncommon.

Additionally the amplifiers are tightly coupled to the driver design, with appropriate power for the drivers (which may well differ between the tweeter and woofer) and usually with protective limiting circuitry to prevent damage on signal overdrive that with a passive speaker could cause driver failure.

Active monitors are not common in hifi systems simply because generally it's more practical to include the amplifier in a single integrated system and as people move upmarket they may choose to retain their speakers but upgrade the integrated system to a set of separate units (traditionally, amplifier, cd player and tuner).

Active monitors also require a power source for each speaker. Owners of hifi systems often have partners who are "cable hesitant" and some delicate negotiation is often required. When finally positioned, there may not be an aesthetically appropriate way of running mains power to an active monitor pair, (particularly on stands), but a relatively unobtrusive and less bulky speaker cable might be able to be concealed more easily, because you can purchase white or translucent cable with the inner conductors left as their tinned silver finish, whereas a power cord is always going to be much more noticeable.

There is also the issue of power management. Passive speakers controlled by an amplifier simply require that the amp is turned off. Active monitors need to have their power controlled separately. While you can, now, purchase cheap wifi-controlled remote power sockets, these are a relatively recent innovation and you still then have to use your phone to turn the speakers on and off; fine in a studio, not so convenient in a domestic scenario with shared users of the system.

However we are starting to see some hifi enthusiasts switch to active monitors. The Tannoy Gold 5 and 8 inch monitors seem to be quite popular for this purpose and there are some enthusiastic reviews on the internet. I use these as the main studio monitors and I do concur that to my ears these are voiced very much in the neutral style that is appropriate for hifi use, as opposed to an often emphasised midrange that may be more appropriate for analytical studio monitoring.

So I think this is why we currently have the split. In my opinion a good pair of active monitors are an ideal solution and are technically superior to passive monitors but you would need to take care to purchase units which are not voiced for an emphasised midrange, which seems to be somewhat common for studio monitors. Apart from the Tannoy Golds, I would expect the Neumann monitors to be very flat, I am not sure what other active monitors are voiced neutrally, most of the SOS reviews seem to indicate that they have some presence boost, which would not be appropriate for hifi use.

[ef37a]

Actives all the way for me. A long time ago the principle of having a separate power amps for bass and treble drivers was called "bi amping"* and the benefits were a higher, high quality SPL than could be wrung from the same drive units fed with comparable power via a high level crossover. And those crossovers were a design nightmare! To get a high enough inductance for a low turnover frequency the coil really had to have a ferrite core and that of course could be a source of distortion. The capacitors are almost always non-polar electrolytics and they are certainly not distortion free. Yes some very top end designs use foil caps but they are big and very expensive (as are air cored inductors!) And finally on X overs? When you have made something that divides the frequencies nicely and doesn't produce too much distortion, you can find the amplifier cannot drive it without going unstable or at best popping fuses or tripping protection circuits!

*Not to be confused with "bi-wiring" which IMHO is largely snake oil.

Dave.

[Hugh Robjohns]

A long time ago the principle of having a separate power amps for bass and treble drivers was called "bi amping"* ...

Just for the avoidance of confusion, bi-amping still involves a high-level passive crossover, just one where the high-pass and low-pass sections (assuming a two-way system) have separated inputs.

There are some theoretical benefits to the bi-amping approach... but not many... If you're going to the expense of the extra amps a fully active system will deliver significantly better performance for no extra cost — an active cross-over is probably less expensive than a good passive one!

In other words, the amps are not connected directly to their respective drivers in bi-amping, but they are in active systems.

*Not to be confused with "bi-wiring" which IMHO is largely snake oil.

No snake oil involved, just well known physics. But the benefits are negligible with low power systems and short speaker cable lengths.

In high power systems it can quite definitely prevent intetmodulation distortions (as well as a bi-amped system).

And finally on X overs? When you have made something that divides the frequencies nicely and doesn't produce too much distortion, you can find the amplifier cannot drive it without going unstable or at best popping fuses or tripping protection circuits!

It's certainly true that the impedance of some passive cross-overs in complex speaker designs can dip to alarmingly low levels which many lesser power amp designs struggle to cope with.

[ef37a]

"In other words, the amps are not connected directly to their respective drivers in bi-amping, but they are in active systems."

Hmm, I did mean a system where the bass and treble units were directly connected to their own PA and line level filters used.
I built such a setup years ago using 2 12" bass drivers and 2m line source speaker. Sallen&Key filters realized with BC109 emitter followers.

No the amps were not built into the cabs (one was KT66s!) but then many of the early 'actives' just bolted the amps etc on the back? And yes, I s'pose if there is a lot wire it can help to double it up but is there a real benefit over just paralleling the extra Copper?

Dave.

[Hugh Robjohns]

Hmm, I did mean a system where the bass and treble units were directly connected to their own PA and line level filters used.

That's a fully active system.

In an active system each driver is powered directly by it's own amplifier, and cross-over duties are performed at line-level in active electronics which feed the appropriately filtered signals to each power amp. Thus, each amp carries a band-limited signal.

A bi- (or tri-) amped system is a passive setup where the cross-over filters for each driver are separated and fed from their own amplifier but all amps recieve the same input. Thus, each amp carries a full range signal.

No the amps were not built into the cabs (one was KT66s!) but then many of the early 'actives' just bolted the amps etc on the back?

Plenty of big studio active monitors mount the electronics separately from the speaker cabinet for very practical reasons. With smaller systems it is more convenient to build the crossover electronics and amps into a dedicated recess in the cabinet.

... is there a real benefit over just paralleling the extra Copper?

Assuming you're talking about bi-wiring, yes, in theory.

With a single cable feeding a passive two way system, the large currents involved in loud low frequency signals will necessarily generate a voltage across the cable's small but finite resistance. That voltage gets added to the HF signal, effectively modulating it and causing intermodulation distortion.

It's the same problem as a three-wire headphone connection, albeit with a different outcome here.

Bi-wiring essentially keeps the LF currents out of the HF cable which is tightly controlled by the amp's high damping factor st one end, and the high-pass filter at the other. Consequently, there is no intermodulation.

Paralleling the cables instead of bi-wiring will reduce the overall cable resistance and thus reduce the cable-induced voltage... but it can only reduce IMD, not prevent it as bi-wiring does.

As I said earlier, in small speaker systems with limited power handling and a relatively high bass roll off the IMD is probably inaudible with single wiring. But in beefy systems with deep bass extension it definitely is. I can hear it on my (passive) PMC IB1s (driven by a Bryston 4B SST2), for example. Biwiring gives a clearer midrange and HF. It just sounds more transparent and cleaner. Subtle, yes, but reliably detectable in AB comparisons.

I run two separate cables from the amp, one to the bass driver cross-over input, and the other to the linked midrange and tweeter inputs. Years back, I experimented with tri-wiring but found no benefit over bi-wiring.

[resistorman]

I would stay off hifi forums

[The Elf]

And all this to play vinyl...

[Hugh Robjohns]

Quite right.

Cassettes are much better. None of that snap crackle and pop...

[Eddy Deegan]

Hugh, you should write a book

[The Elf]

Quite right.

Cassettes are much better. None of that snap crackle and pop...

[Wonks]

Though they can be very chewy.

Pencils at the ready!

[Zukan]

All tapes matter.

[jodaki]

...you have to put some boundaries on that. As I said, a very good passive may well be better than a cheap active. But a good, professional active system will blow passives out the water every time...

Fab information as always Hugh. Thanks. And thanks to everyone else who replied.

[FrankF]

Though they can be very chewy.

Is this some kind of new-fangled iron supplement I haven't heard of?

[RichardT]

And all this to play vinyl...

I wouldn’t be surprised if the reason they don’t like active speakers is partly that they often use DIGITAL processing.

[Hugh Robjohns]

I think the real reason is that actives mean you can't purchase one or more sets of tweaky speaker cables, or spend hours comparing and upgrading power amps, and their interconnects.

Basically it removes hours of fun and upgrading...

[MOF]

Basically it removes hours of fun and upgrading...

We should join their forums, explain why they're wasting their time and then introduce them to the joys of modular synths, that's SERIOUS hours of fun and upgrading.

[Arpangel]

Basically it removes hours of fun and upgrading...

We should join their forums, explain why they're wasting their time and then introduce them to the joys of modular synths, that's SERIOUS hours of fun and upgrading.

Thats what I was thinking when I wrote my post, my God, talk about glass houses
Bi-wiring? no never heard any difference, never.