Can someone explain "Crossover" to me?

[ack1961]

Hey guys - I've been wrestling with this, and I still don't understand the "Crossover" section of my Peavey TNT130.
I guess that I really don't understand the concept of Bi-amping.

from the TNT130 manual:


As an experiment, here's what I did: I took the High Output from the Crossover section and put it in to the Input of a little SWR 60W Combo amp.
When I power on the SWR, I get sound from both amps, which I was expecting.
Here's what's puzzling: In this configuration, the SWR is louder at 3 then it is at 10 by itself.
If I put both amps at 5, the room shakes. 

I'm pretty certain that since their example (XC 400) is 210W @ 4 Ohms, that the idea is to bi-amp with a more powerful amp/cab or combo than the TNT130.
Is the purpose of Bi-amping simply to have a single source signal (the bass) spread out on larger stages? Maybe for small venues without PA systems?

Sorry if these questions are stupid, but I've failed trying to learn exactly what it does and why.
Thanks,

[the mojo hobo]

A crossover's function is to split high frequencies from low frequencies and direct  each to suitable speakers.  Lower  frequencies take more power to produce than higher  frequencies.  What Peavey is suggesting is to use the TNT for the highs and add a power amp and speaker for the lows. The reason your SWR was louder is because it was receiving a signal that was already amplified by the TNT pre-amp.

IMO bi-amping is more suitable for keyboards than bass guitar.

To simplify: In a bass guitar application a bi-amped system will direct the bass part to the bass speaker and the guitar part to the guitar speaker.

[ack1961]

A crossover's function is to split high frequencies from low frequencies and direct  each to suitable speakers.  Lower  frequencies take more power to produce than higher  frequencies.  What Peavey is suggesting is to use the TNT for the highs and add a power amp and speaker for the lows. The reason your SWR was louder is because it was receiving a signal that was already amplified by the TNT pre-amp.

IMO bi-amping is more suitable for keyboards than bass guitar.

To simplify: In a bass guitar application a bi-amped system will direct the bass part to the bass speaker and the guitar part to the guitar speaker.

Thanks for the great explanation - very much appreciated.
I can envision some pretty cool applications for it.

I can probably do some damage to the little 60W/12" practice amp, but it was an interesting experiment.

[Freuds_Cat]

I've been running a Bi-Amp rig for over 25 years.

The Hobo's description is right.
One of the benefits of running a bi-amp rig that most ppl dont consider is that changing the crossover frequency to suit each different stage/room can be a very suitable and accurate fix to stage sound problems. Sounds complicated but its really not. Selecting a higher crossover point for instance directs the lower frequencies that were going into the top cab (in my case running a single EV 12") down into the lower cab (a single EV 15"). Even though we are talking about the same frequencies here the voicing changes due to the size of the speaker and cab. The effect is similar to selecting different cabs in emulation software or on a pod. Its a cool and functionable side effect of Bi-amping.

[ack1961]

I've been running a Bi-Amp rig for over 25 years.

The Hobo's description is right.
One of the benefits of running a bi-amp rig that most ppl dont consider is that changing the crossover frequency to suit each different stage/room can be a very suitable and accurate fix to stage sound problems. Sounds complicated but its really not. Selecting a higher crossover point for instance directs the lower frequencies that were going into the top cab (in my case running a single EV 12") down into the lower cab (a single EV 15"). Even though we are talking about the same frequencies here the voicing changes due to the size of the speaker and cab. The effect is similar to selecting different cabs in emulation software or on a pod. Its a cool and functionable side effect of Bi-amping.

I was dorking with the frequency settings last night, just to see how it affected the two signals.  Although our jam room is small, the changes are still quite noticable.  Thanks for the input. Cheers!

[jumbodbassman]

keep on ething in mind.  the low end power needs to be at least 2-3 times that of the high end.

[Psycho Bass Guy]

It doesn't HAVE to be. With my PA, I can easily run both of my Bag End 2x12's off one side of my Crown MA1200, giving them 300 watts each with a Power Base 3 feeding my Electrovoice SX300's 300 watts each and I have "boom" to spare, however those are all incredibly efficient speakers at what I've got them doing.