Different Amplifiers on Bass and the Other Drivers

[Elkerton]

I have friends with 3 way speaker systems and amplifiers of different manufacture driving the woofers and the midrange/tweeters. None of the amps have volume controls. The systems sound fine without their having had to adjust the outputs of the amps. I would have thought that there would likely be some matching of levels necessary because of different input sensitivities. Did they just get lucky, or am I wrong?
(I hope this isn’t a stupid question)

 

[DVDdoug]

You're right!

Different amplifiers have different gain. There's no "industry standard" except that there is a standard practice that power amps should have enough gain to reach full power with a line level input. But even that's fuzzy because line-level isn't calibrated (especially in home equipment) so some line outputs are hotter than others, some recordings are louder than others, and sometimes there's a volume control. Plus, there are different pro and consumer line level standards.

Usually with b-amped and tri-amped speakers, there is a line-level active crossover, and no speaker-level crossover. Active crossovers usually have adjustments for each frequency band. In that case the amplifiers don't have to be gain matched but the setup needs to be adjusted-calibrated.

The drivers may not have matching sensitivity either. It's not uncommon for the crossover in a speaker to attenuate the signal to the tweeter to make it match the woofer.

Oh... Most home-theater subwoofers are active (a built-in amplifier) and they have to adjusted to match (or to taste).

 

[staticV3]

I would have thought that there would likely be some matching of levels necessary because of different input sensitivities. Did they just get lucky, or am I wrong?
(I hope this isn’t a stupid question)

In other words, the levels are likely matched upstream of the Amps.

Each Amp get a different, already adjust level that, combined with the Amp's voltage gain and its driver's voltage sensitivity, results in matched SPL output between drivers.

 

[Hear Here]

I would have thought that there would likely be some matching of levels necessary because of different input sensitivities. Did they just get lucky,

In other words, the levels are likely matched upstream of the Amps.

Each of the 3 drivers are likely to require greatly differing power to sound in harmony. For example the ATC active 50 speakers use an active XO for the 3 drivers and apply a 50 watt power amp for the tweeter, 100 watts for the mid and 200 watts for the bass driver.

The example the OP quotes are likely in harmony (if in fact they are) by preamp control.

 

[DVDdoug]

For example the ATC active 50 speakers use an active XO for the 3 drivers and apply a 50 watt power amp for the tweeter, 100 watts for the mid and 200 watts for the bass driver.

Wattage doesn't come into-play until you start clipping.

And power is not necessarily related to gain. You can have a higher power amp that's quieter than a lower-power amp with the same input.

The bass range usually does require more power. And sometimes woofers aren't as sensitive as tweeters so in an active speaker the woofer amp may have more gain and more power. And in an active speaker, there may additional gain from EQ to extend the low frequency response.