Crossover vs. Sub Out

[Stidd]

My Band Just Picked up some Live Sound Equipment so we could be equipped to play parties and small non equipped Bars and such. The equipment is in my Basement Studio so I have the priviledge of playing with and learning the equipment. I ahve so many questions is really kinda scary.
Here is the Gear Line Up.

Mackie CFX16 Mixer

Main output from Mixer to
Crown CE2000 Powering the Following
JBL SF15 15" 2 Way Speaker Cabinets as FOH

Aux output from Mixer to
Crown CE1000 Powering the Following
JBL SF12M 12" 2 Way Stage Monitor as Monitors
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In a Nutshell, what I was hoping to find out is information on this equipment. I realize that there is alot that can be done with different wiring scenerios and equipment.

1. Speakers Can be Run in Either Parrallell or in Series Right?

2. If I were to get a Passive Sub-Woofer and a Mono PA, would I be able to Use a Cross Over from the Main Output of the Mixer instead of SUB Out of the Board? Or is the Best Scenerio to use the SUB out of the Mixer.

3. With the Above Configuration (w/o a Sub) is it recommended to run a Bass Guitar and Kick Drum Into the Board?

4. Recording From the Board to a Tape Deck or MiniDisc..... Any Info on This would be Great.
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I Realize that I'm asking alot here. Just want you all to know I'm greatful for the help. As Soon as I'm Up to Speed on this, I will be around to help others out as well...

Thanks Again,
Stidd

 

[knightfly]

1. Speakers can be either parallel or series. Paralleling two identical speakers drops their characteristic impedance to half, so two 8 ohm speakers would make a 4 ohm load in parallel. Series adds impedances, so the same two speakers would make a 16 ohm load. If your amp can handle the lower impedance, parallel is louder since the same output is connected thru 1/4 the impedance and will therefore put out up to 4 times the current if the amp can source that much. Most stage type speakers are set up so that if you plug a second phone cord into a speaker and run it to another speaker, they are in parallel.

2. You could use a separate cross-over from the main outs, but the Mackie has a built-in 18 dB/octave crossover at 75 hZ, so I would try that output into the mono amp first. You could always get a 24 dB/octave crossover later if the internal one didn'g give you a tight enough sound. (The higher the dB/octave rating, the narrower the band of freq's that are being reproduced by two different speakers, and the less possibility of phase cancellations.)

3. I do it all the time. The sub will usually make your vocals stand out better, because you're not asking the same speakers that are reproducing your voices to also put out massive bass power for kick and bass guitar. For this reason, a more adjustable crossover might work better with the sub, so you could raise the crossover freq. and therefore use less power in the low mids, leaving more headroom for vocals/guitars.

4. Recording from any board in a live situation is less than a perfect way to go. It's OK for reference tapes to learn how to improve your act, but won't give you the same sound that people in the room hear, or even close. If that's what you want, you would be better off using an XY pair of mics with a separate preamp into the MD or tape deck, and placing the mics overhead out of the crowd's way. If you're using a separate sound man from out front, the mics could be placed there as well. Whatever the sound person hears would be pretty much what got recorded, if levels are correct, etc...

Recording from that particular board in a studio situation will work OK since you're not using live speakers in the room, etc, but if you do very much of this you'll probably decide to get a more recording oriented board sooner or later... Steve