What matters most in speaker design?

Its like asking "What is the most important organ in the body: brain, heart or lungs?" You need them all working together properly!

Wireless200,

The key with active speakers is moving the crossover to the line level side of the signal path rather than the high power level. This reduces distortion (capacitors have a sound and especially caps driven with high power signals can add distortion). This means that power amp/cable/speaker interface no longer matters, since there is line level cabling directly into very high (10K) impedance of the speakers. Furthermore the three separate amplifiers in a tri-amplified active three way speaker will only need to drive a limited bandwidth (say 20 to 400 Hz for the bass, for example). The limited bandwidth prevents IMD distortion from the huge 1 amp current needed by the bass woofer from affecting the tiny 1 milliamp current used by the tweeter. Another aspect is the ability to correct for phase - so the designer can maintain as near as possible an ideal transient/impulse response (good on drums/percussion/piano). Yet another aspect is the improved power performance due to less losses from heating up a passive crossover parts (roughly 3db louder for the same power). Low power requirements can also allow the design to be tailored - for example a tweeter is where the worst of the high order and most audible crossover and IMD distortion might be expected to show up - you could easily drive the low power requirements of the tweeter and most of the midrange in Class A while using Class B for the power hungry woofer. Finally, and related to the last few points, one can better protect the speaker from destruction due to being overdriven (often the tweeter blows when a conventional speaker is driven too hard but in an active speaker the tweeter still gets clean power even if the woofer is being overdriven).

Those probably aren't all the advantages but that is what I could think of at the moment. Of course, for those who like to tailor their sound like "mix and match" fashion accesories then the active speaker is limiting. However, if you want the speakers to produce music as closely as possible to how it sounded in a studio or in mastering then the appropriate active speaker will ensure you are quite close (simply because there are much less variables when a good 50% of the reproduction chain that you have matches what they used)

as i am new to hifi, can you give some examples of speakers/speaker companies that are "active" speakers?

what type of amp does one use with active speakers? or does one use two amps?

if there's a website that explains all this please let me know. didn't find it through google.

thanks, jeff

Jeff,

can you give some examples of speakers/speaker companies that are "active" speakers?

Examples of companies making active speakers are nearly too many to list here are a few (not exhaustive)
Meridian
ATC
PMC
B&O
KRK
Adam
K&H
NHT
Mackie
JBL
Tannoy
Yamaha
Westlake
Paradigm
Barefoot
Dynaudio

what type of amp does one use with active speakers? or does one use two amps?

A preamp only - or if you have a source with volume control then you can connect that directly (for example Benchmark DAC1)

if there's a website that explains all this please let me know. didn't find it through google.

Here is a lecture you can listen to Bob Stuart of Meridian

Jeff, ATC makes (truly excellent) active loudspeakers - I believe Shadorne owns a pair.

You'll find a lot more active loudspeakers in pro audio than this hobby. One reason being audiophiles really run the gamut in terms of power amplification, and they also are prone to a lot of buying/trying of them.