@ronboco wrote:
Why does an onboard amp in an active speaker pair better than separate amplification ?
In an active config. an onboard amp by itself doesn’t pair better than an outboard ditto. Remember, active can be an outboard solution as well.
Are the drivers different than a passive speaker?
Not necessarily.
Are the crossovers different than in a passive speaker?
Yes, active XO’s are placed prior to amplification on signal level, not on the amp’s output side between that and the drivers taking the full power.
It seems the only thing active does is eliminate the need for an external amp.
No, primarily active eliminates the passive XO between the amp and drivers, and this gives the amp(s) much better control over the drivers sans intervening passive XO components, which in turn has the drivers perform more accurately to what’s fed to them by the dedicated amp sections.
@ghasley wrote:
An example would be the speaker designer could match the appropriate amp to the appropriate speaker driver to achieve their design goals optimally.
While amp matching certainly isn’t irrelevant, its importance - in some respects - has been blown a bit out of proportion, if you ask me. Overall, active config. also allows the designer to downscale amps, while getting away with it, being the output power is more effectively used sans passive XO’s, and they also perform (i.e.: sound) better actively. As a bundled solution that comes in handy with more compact designs.
Not trying to diminish amp matching, as per your next quoted paragraph below, but often it means allowing the designer to potentially downscale while dedicating amp sections to their specific driver dittos.
An extreme mismatch example would be for an active two way where the amp driving the top end was a class d plate amp and the low frequency driver driven by a class A 10 watt amp.
Indeed. It’s what I do myself in my outboard config. active setup; lower wattage class A from the lower to central mids on up, high power class TD taking over down to the upper bass, and high power class A/B from here to 20Hz. Common wisdom, very generally, may dictate class D variants to the lowest octaves, but I’ve found using my class A/B amp (MC² Audio) to serve better from 20 to ~85Hz and having a bigger, more positive effect on the remaining frequency spectrum above in comparison to using my class TD Lab.Gruppen amp here, which is no slouch either, I might add. Interestingly the MC² Audio amp is the better full-performer vs. the Lab.Gruppen (but not the Belles class A, which is the best of the bunch), to my ears, and yet the overall sonic picture has it serving better in the subs region - go figure.
That’s what an outboard solution allows you, to use external quality amps and experiment with their implementation in the respective frequency spectrums.
