ATC active vs passive

[steve_1979]

The largest limitation in passive loudspeakers is the passive crossover. It's large, expensive (especially in a 3-way) and is quite limiting in it's function of combining the output of separate drivers in a multi-driver system. During testing we have found that active implementation of a loudspeaker far outweighs any advantage gained from a very high performance outboard amp (of comparable power).

We fully understand that an active system restricts some of the 'adjustability' of a system powered by separate outboard amps but, there are advantages based on solid engineering that apply to all multi-driver loudspeakers, not just ATC's

Here's the full run down:

1) More accurate crossovers
•Active filters allow independent control of level and phase(time). This is not possible with passive crossovers. With a passive crossover any changes you make to the circuit affect both level and phase. The benefit this allows is that we can adjust for the crossover to have a perfect magnitude response and phase response. The result is that the stereo imaging is much more stable and the tonal balance of instruments is improved.
• An active filters performance is not changed by the temperature of the drive unit voice coil as they are not directly connected to them. A passive crossovers performance (filter shape and crossover frequency) will change with voice coil temperature which, increases with SPL (input power). This leads to passive loudspeaker systems having a slightly different sound when driven at low SPL compared to high SPL. The performance of active ATC systems changes very little with drive level.
•More efficient crossovers. Active crossovers do not need to use series inductors to achieve their filter shapes. Series inductors have resistance that reduces bass driver efficiency and also increases the Q of the low frequency tuning.
•More cost effective crossovers. Passive crossover networks use large, bulky and expensive components in order to deal with the high voltages from a power amplifier. Active crossovers offer better performance for lower cost.

2) Lower Intermodulation-Distortion
As the separate amplifiers in an active system are located after the crossover, they only operate over a limited bandwidth. This reduces intermodulation-distortion and, in comparison to a passive system, even a bi or tri-amped passive system, an active system will show 15 – 20dB lower intermodulation distortion.

3) Improved Frequency Response and Stereo Matching
An active system can very simply feature individual gain trims for the two, three or four amplifiers involved. This allows very simple fine tuning of the frequency response and the stereo matching. Similar matching in a passive system would involve the replacement of large, soldered passive components which, in practice, is difficult and time consuming for the manufacturer.

4) Lower Cost for Higher Performance
Because an active system is designed, engineered and implemented by a single manufacturer into as compact a package as the design allows, cost is saved on electronics case work and packaging and the manufacturer can invest in real performance enhancing changes or pass the saving on to the customer.

Kind Regards, Ben

 

[steve_1979]

Clicky

 

[SteveR750]

I'd be more impressed if the streamer and DAC was all included. If only to see how you figure out your business plan Mr Nordost.

 

[jjbomber]

Who do you mean by we?

 

[SteveR750]

Who do you mean by we?

He's quoting the reply from ATC, who are the "we" in this excerpt.

 

[jjbomber]

He's quoting the reply from ATC, who are the "we" in this excerpt.

Thank goodness for that. We wouldn't want someone on here representing an active speaker company while pretending to be a member of the public now would we*biggrin**biggrin**biggrin*

 

[SteveR750]

And this still applies, one of the more amusing intros, though these thing are relative but hi fi reviews are not known for their (intentional) side splitting content:

"There's something odd about ATC's ACM40, it doesn't look or feel like almost any other loudspeaker in its price class. It's almost as if someone has forgottne to style it, liike they've taken three drivers and put them in a box designed to do the job, and then gone home"

There is something appealing about them, and ATC generally, in the way jet fighters and battle ships are interesting.

 

[Alec]

someone else's words, without quotation marks, followed by a link to a thread many know, or want to know, nothing about.

Do you think that's a particularly great way to present a thread?

 

[steve_1979]

someone else's words, without quotation marks, followed by a link to a thread many know, or want to know, nothing about.

Do you think that's a particularly great way to present a thread?

Well I'll consider myself well and truly reprimanded. *sorry2*

I just thought it may have been of some interest to a few members here. A bit like the famous PMC YouTube quote on the same subject.

 

[steve_1979]

Can I come out of the dog house now?

 

[lindsayt]

The largest limitation in passive loudspeakers is the passive crossover. It's large, expensive (especially in a 3-way)

No it's not. The largest limitation in any speaker comes from the actual drivers used and their ability to convert the electrical signal fed to them into the sound that we will hear, with a good amount of fidelity under all normal operating circumstances.

Passive crossovers may be large, compared to the size of a flea. But they are not large compared to the size of proper bass drivers, or of an active crossover combined with an amp pack.

Passive crossovers are expensive compared to a second class stamp. They are not expensive compared to an active crossover, or a bass driver, or a speaker cabinet, or an amp pack for an active speaker.

Why did Ben from ATC make these false / misleading statements?

 

[SteveR750]

I'm waiting to listen to them, but the HF Choice review states "prodigious bass", which suggests strong and powerful. The infinite baffle and subsequent natural roll off (spec is -6dB at 48Hz) on paper suggest otherwise, and no amount of active crossovering is going to change such fundamentals unless it resports to some DSP, which of course you can in passive mode too. This assumes of course that most ported speakers have artifically extended bass (which they do by design) but the in room LF responses probably more often than not resemble a line of camels. I wonder though if David Price meant prodigiously controlled...

 

[Jota180]

"Bart LoPiccolo, National Sales Manager for Genelec, Inc., takes the definition of active a few steps further, explaining that Genelec’s speakers are active because, “they have active electronic crossovers before the amps, they have dedicated amps for each driver, each channel has protection, and there are room response controls per driver.” Active speaker proponents like LoPiccolo believe that an active speaker system has certain advantages over a passive system due to the fact that the crossover components, amps, drivers, and speaker enclosures are all manufactured with one another in mind.

Although high-end passive speakers can contain high-end crossover components, LoPiccolo says that, by nature, passive crossover components and passive speakers have some intrinsic drawbacks. “Passive crossover systems dissipate heat, and can lose as much as 30-percent of the amplifier’s power,” LoPiccolo states. “And as the crossover components heat up, the performance of the speaker changes. So a movie may sound differently toward the end than it did in the beginning,” he continues."

 

[Jota180]

The largest limitation in passive loudspeakers is the passive crossover. It's large, expensive (especially in a 3-way)

No it's not. The largest limitation in any speaker comes from the actual drivers used and their ability to convert the electrical signal fed to them into the sound that we will hear, with a good amount of fidelity under all normal operating circumstances.

Passive crossovers may be large, compared to the size of a flea. But they are not large compared to the size of proper bass drivers, or of an active crossover combined with an amp pack.

Passive crossovers are expensive compared to a second class stamp. They are not expensive compared to an active crossover, or a bass driver, or a speaker cabinet, or an amp pack for an active speaker.

Why did Ben from ATC make these false / misleading statements?

All things being equal, an active version of a passive speaker should have a number of advantages because of the active crossover. There's no point comparing passive speaker of one manufacturer with an active of another. Too many variables.

ATC are a good brand to test the differences between active and passive.

 

[steve_1979]

And this still applies, one of the more amusing intros, though these thing are relative but hi fi reviews are not known for their (intentional) side splitting content:

"There's something odd about ATC's ACM40, it doesn't look or feel like almost any other loudspeaker in its price class. It's almost as if someone has forgottne to style it, liike they've taken three drivers and put them in a box designed to do the job, and then gone home"

There is something appealing about them, and ATC generally, in the way jet fighters and battle ships are interesting.

Great description. Apart from the dodgy grills which need covering in transparent cloth, I do rather like the look of the 40's though. That's what real HiFi should look like.

 

[Jota180]

The new SCM40A do look much better than previous versions. I'm going to have a pair of Dynaudio Focus 200XD on loan in a few weeks time. Should be fun.

 

[SteveR750]

If they (passive ACM40) work in my system, then I'd be inclined to consider a Hegel HD12 driving a pair of the active ATCs as a future upgrade. A laptop, one small box, two leads and two speakers. Could be minimalist nirvana.

 

[matt49]

The largest limitation in passive loudspeakers is the passive crossover. It's large, expensive (especially in a 3-way)

No it's not. The largest limitation in any speaker comes from the actual drivers used and their ability to convert the electrical signal fed to them into the sound that we will hear, with a good amount of fidelity under all normal operating circumstances.

Passive crossovers may be large, compared to the size of a flea. But they are not large compared to the size of proper bass drivers, or of an active crossover combined with an amp pack.

Passive crossovers are expensive compared to a second class stamp. They are not expensive compared to an active crossover, or a bass driver, or a speaker cabinet, or an amp pack for an active speaker.

Why did Ben from ATC make these false / misleading statements?

All things being equal, an active version of a passive speaker should have a number of advantages because of the active crossover. There's no point comparing passive speaker of one manufacturer with an active of another. Too many variables.

ATC are a good brand to test the differences between active and passive.

In the real world no buyer is limited to a choice between a passive speaker and the same model in active form. So whilst the comparison between ATC actives and ATC passives is interesting as an academic exercise, it's of limited interest to actual buyers.

Anyway, Lindsayt is right. The biggest limitation on passive electrodynamic speakers isn't the crossover. By far the biggest limitation is the nature of electrodynamic drivers.

And there are two other limitations that are more significant than passive crossovers: (i) speaker enclosures, and (ii) using a crossover at all (whether passive or active). If you could make a speaker that didn't use electrodynamic drivers, didn't mount its drivers in boxes and didn't use any crossovers (at least not in the 'presence zone' above c. 350Hz), then you'd have a speaker that was far more accurate and free of colorations than any multi-driver electrodynamic box speaker.

And speakers of that kind have existed for over fifty years -- i.e. electrostatic and planar magnetic panel speakers. This is the only way to make speakers that distort as little as good quality hi-fi electronics do. Back in the 1950s Arthur Janzsen put together a then SOTA system consisting of turntable, amp and his own electrostatic speakers; he was able to show that the speakers were the least distorting element in the chain. No electrodynamic speaker could come close to that performance.

 

[jonathanRD]

It looks like we will soon be able to demo both the passive and active versions of the new Epos K range. It would be an interesting comparison to hear the passive K2 with a Creek 50a versus an active K2. I intend to have a listen to the active version at the Bristol Show - I just hope they are not too good otherwise I am going to regret buying my RS5's!