Ajani said:
There seems to be a bit of hostility on the forum about the recommendation of active speakers. So I wonder, when should active speakers be recommended? Is it only if the OP specifically asks for an active rec?
...
But back to the main question:
When should active speakers be recommended?
In my mind there are 3 definitive use cases for active speaker configurations at home:
1. Home theatres.
2a. Hi-Fi - constrained space setups.
2b. Hi-Fi - Build from scratch super-premium.
Now, before I go on to explain why, let me correct a common misconception that active speakers are always powered speakers. No, they need not be. The difference is as follows:
Passive Configuration:
In this configuration the amplification of the line-level signal happens before the frequency isolation (high-pass/band-pass/low-pass). So a passive chain looks somewhat like this:
Digital source -> DAC -> Analogue Pre-amp -> Amplifier -> Passive Cross-over -> Drivers (Low/Mid/High)
OR
Digital source -> Digital Pre-amp -> DAC -> Amplifier -> Passive Cross-over -> Drivers (Low/Mid/High)
OR
Analogue source -> Pre-amp -> Amplifier -> Passive Cross-over -> Drivers (Low/Mid/High)
The important aspect in all the above variations is that the amplification stage always precedes the cross over stage.
Active Configurations:
In this configuration the amplification is applied after the frequency isolation (high-pass/band-pass/low-pass). So each driver has its own amplification. Hence the active chain looks one of the following:
Digital source -> Digital Pre-amp -> DAC -> Active Cross-over -> Amplifier (Low/Mid/High) -> Drivers (Low/Mid/High)
OR
Digital source -> Digital Pre-amp -> Active Cross-over -> DAC(Low/Mid/High) -> Amplifier (Low/Mid/High) -> Drivers (Low/Mid/High)
Again the important aspect is in all the above variations the amplification stage is applied after the frequency isolation stage. In some configuration the active crossovers, the amplifiers, and occasionally the DACS (as in Meridian DSP products) are installed within the speakers, thereby requiring the speaker to be powered. But these components can as well be externalized as in the case in Linn Active configs, in which case the speakers need to be powered.
Performance implications:
1. Passive cross-overs introduce more noise and distortions than active ones. Removal of these need masking circuitry which as a side-effect introduce coloration. Hence a passive speaker can never be as accurate in rendition as the active ones.
2. Passive cross-overs are inherently less efficient in terms of voltage and current losses. Hence a passive speaker can never be as loud as an active speaker for the same degree of amplification.
3. Passive speakers need the amplified signals to travel between the amplification stage and frequency isolation stage. Amplified signals create a larger electromagnetic field around the conductor and so are more susceptible to inductive interference. Therefore amplified signals cannot be made to run efficiently over large lengths as is required in home-theatre setups. Drivers in actives configurations can therefore be installed much further away from the source provided the amplification takes place within the speaker itself. It’s even better if only the pure digital signal is carried right up to the speakers and the DA conversion takes place within it.
Coming to the justifications for the ideal use-cases of active speakers:
1. Home-theatres: predominantly implications 2 & 3
2a. Constrained space hi-fi: predominantly implication-1; lower noise allow better near field listening as the rendition is sans minute distortions which are noticeable when one sits closer
2b. Super premium hi-fi: predominantly implication 1 & 2; because at stratospheric levels of audiophile equipment, the most important objective is to make the sound as accurate and as loud as possible.
As a matter of fact, many passive speaker design geniuses are now appreciating the benefits of active loudspeaker design and have started offering such options for their flagship offerings. Take a look at this
article:
Cheers AVEX