How much power output with gain all the way down?

[aidanskatez]

I'm getting ahead of myself again.. Thinking about upgrades when I'm not even done installing my current system. Anyways, I think I want to do a 3 way active front stage with some Dayton Audio components (an 8" midbass a 4" midrange, and a tweeter). Obviously it would be nice to run everything off of one amp but life isn't always fair.

My main question is. How much will an amps power output be reduced if the gain is turned all the way down?

I was looking at the JL Audio XD600/6v2 which is 75 watts per channel because the midbass drivers I've looked at are rated at 80 watts rms and the midranges are rated at 30 so I think the amp would work for those but the tweeters are only rated for 15 watts rms.

If it's not possible to use that amp I'll just connect the tweeters to my HU or to something like a Rockford 250.4 40 watts per channel.

Also, am I correct in assuming that if my midbass driver is only playing 60-300 (not exactly those points) that it could take more power? Or that drivers in general can take more power if you decrease the bandwidth they play?

[SPLEclipse]

That's not possible to answer; there's too many factors.

Consider that the spectrum of frequencies that the tweeters reproduce are probably around ~5% of the total "energy" of the signal, meaning that for equal gain and theoretical power output on all channels and speakers the tweeters will be only getting a small fraction of the total wattage. Also consider that on dynamic material like music the actual power at the speaker will swing wildly.

As for the midbass... you're assumption on bandwidth taking up more power is somewhat correct, but because the majority of the actual power on the spectrum is at lower frequencies it's not a noticeable difference. The inductive load from the speaker will also compensate for this by presenting higher and higher impedance as frequencies increase. Power handling is defined by the lowest frequency you expect to play (vented applications being somewhat different because you have to worry more about heat than a sealed or IB application where mechanical handling is the primary concern). For a really dynamic system on good speakers I would never use 75 watts on a midbass. You need as much power as possible to cleanly reproduce dynamic bursts. Not saying you have to do it, but a lot more power would be ideal. If you put (as an example) 300 watts on a midbass your average power at the speaker will probably only be 20-40 watts because of dynamic swings. You might see power jump for brief fractions of a second, but never continuously unless you are playing a sin wave at 0dB recording volume.

[SPL Addict]

There is no definitive answer. At least you said which amp you were looking into but I'm not going to look at its gain levels, but I will give some info

First What important is your HU preout voltage in relation to your amp input sensitivity. Some amp are 5v - .2v (5v bring the lowest) and my HU for instance is 4v so that will be close to rated power on the amp lowest setting, some people boost signal aswell with EQ's, but there is many setting in HU to back off to actually make less power/preout voltage

But that is all unnecessary IMO. You can safely overpower speaker if your signal is not clipping and a narrow bandwidth, but that's all user preference.

I would run active and open lpf and hpf and use bass blocker (capacitor) to cut frequency for your mid bass and highs you can, now it's possible to distort your signal with a too large of a bandwidth for 1 speaker to play, but you would have to see what your driver is capable of and what you want.

Also the bass blocker info can be found online it needs to work off impedance of the speaker

[aidanskatez]

Thanks for the info SPL eclipse and addict. I don't mind overpowering a speaker but I'll just play it safe and go with two amps then. A low power 4 channel for the 15 watt tweeter and 30ish watt midrange. And a high power 4 channel for my midbass and rearfill or possibly just double up on midbass. I've heard good things about the Crescendo PWX 8 and 10" and they have good specs. I might build the system around those. What are your experiences with the PWX's?

[SPL Addict]

I had 4 pwx 6.5 and they were nice but I liked my prv a bit better m.