PA system upgrade suggestions?

[Sky Blue Lou]

This is posted at RP in the Live Gear forum. We don't have one of those so this looks like a decent place to drop it.


Hi guys - I'm gettin' the urge to acquire some gear. Well I'd like to step up the level of the PA system anyway. I'm turning over possibilities and I'd appreciate your thoughts.

I'll start with what we have:

Mackie VLZ 1604
4-way compressor for vox
BBE Maximizer - 2 channel Main/Monitor
Alesis multiverb or some such - depth for vox
Some Behri effects box - for oddball shit - telephone voice, etc.

All that stuff is fine and I have no desire to change any of it.

Power side:

Tapco Juice (by Mackie) 2500 Power amp - 700 watts/side into 4 ohms
Peavey SP7G speakers - handle 600 watts continuous, 2400 peak
Older Peavey XR600B Powered mixer - This is our monitor amp, 210/300 watts into ---
Older Peavey MDJ 1150 Speakers - Damn big for floor monitors.

Concerns and questions:

I've always worried about relying on one amp - if she croaks we're a no-show. I suppose we could use the Peavey for vox and go w/o monitors in a pinch but I think it might be a tad chaotic.

The big speakers can be bi-amped so I was thinking another Juice and a crossover. I wouldn't need as much power for the high side so I could step down to the 1400 and still have plenty of headroom and enough to sub for big brother if it goes down. Bi-amping should give a better sound and more control as well, no?

Monitors - Another amp and passive floor wedges? We are trying to keep the monitors for vox only. Both guitar amps and the soon-to-be new bass amp have direct outs and we want to try the guitar cabs on the ends of the stage facing center as opposed to the typical back line. The Peavey can certainly handle the job but as mentioned the speakers occupy a lot of floor space. Also the Peavey won't mount in a rack. (Speaking of racks...)

One note before I talk about racks: The Juice amps are mono/stereo/bridged mono. They are essentially two amps in one. We run mono, one input and two sends to speakers w/ separate volume controls. I take it this is standard stuff? Has anyone used this configuration as two amps with one side taking main input/output duties and the other side doing monitors? I can daisy-chain the speakers in normal mode but can't if bi-amped.

Racks:

I want all this shit in one rack, hooked up, with the snake and speaker wires coiled and ready. I am so fuckin' sick of setting all this shit up for every gig you do not know!! (We should have done this first, I know...) I've looked at the SBK Gig Rig but besides being bloody expensive I'm not sure I could fit the snake and speaker cables in there once loaded. We're leaning toward building one - it's gonna weigh a ton!! Suggestions?

All right - done. There are no budget constraints other than reality. A couple thousand tops - I should think we can stay well within that.

I appreciate your thoughts and recommendations. I'll check back often.


lou

 

[drstawl]

Are you gonna wanna shlep an extra amp (like a big QSC) in case your Tapco goes Flatco????

 

[Sky Blue Lou]

Are you gonna wanna shlep an extra amp (like a big QSC) in case your Tapco goes Flatco????

Well yeah. Hence the bi-amp questions.


lou

 

[easychair]

Lou,

You could get a pair of Mackie SRM-350s for monitors. You could try bi-amping the SP-7s with the Tapco, see if it's enough power for you.

 

[Sky Blue Lou]

Thanks for the input easy. The SP7Gs have 4 inputs; 2 normal and 1 each high and low. I assume that means I could daisy-chain them in normal mode - 1 in, 1 thru. If Bi-amping I think I need both ouputs off the Tapco, 1 per side. So I'm leaning towards a less powerful amp for highs and use the existing one for lows. Then if the big one fails I could use the less powerful one in bridged mono as a backup, just revert to daisy chaining the normal ins. I may have an issue with impedence though. The Tapco wants 4 ohms minimum in bridged and the SP7s are 4 each.

This shit makes my hair hurt. More homework required. And I haven't addressed the monitor issue yet. I'll look at those Mackies.


lou

 

[easychair]

Redundancy is never a bad thing at a gig, that's for sure.

As far as the speakers go, you can't daisy-chain when bi-amping, but you could certainly run two cables from each side of the amp, two for highs and two for lows, if you wanted to do it with one amp. It sounds like you want to go with two amps anyway, but it can be done with one amp.

If I was using one amp to drive 2 4 ohm boxes, I'd run in stereo or parallel mono, not bridge mode. You get pretty much the same power, but you don't have the impedance worries.

I think looking for a one-rack solution is a little nuts. Someone's gonna pop a disk. But you are from NH, you'll do what you want anyway.

I'd get a separate rack for the amps and crossover, myself, with a rack panel on the back that had all the input and speaker jacks on it. Or get one with a couple extra spaces so you can hold your speaker cables in it, if you are feeling masochistic. That way you could leave them hooked up. Use the binding posts and bare wire to hook up the cables if you go this way.

And I'd get one of those 10 space over 10 space angled racks for my mixer, etc. There might be enough room for a small snake.

Splitting them up may come in handy, if you ever want FOH away from the stage and amps, too.

Hosa makes some 20 foot IEC power cables, you can get a couple and tape mic cables to them for the monitors, to simplify that step. You could have them hooked up in the same rack as your PA amps.

Your setup would go like this:
Set up speakers and monitors
Uncover FOH, plug it into juice, and run the snake.
Uncover amp rack, plug it into juice, run speaker cables and AC/signal cables for monitors
Hook up PA and monitor sends from FOH to amp rack, use a little snake, labelled.
Rawk.

 

[Sky Blue Lou]

Good stuff easychair - thanx.

Questions - How do you run two speakers/outs off one side of the amp? Splitter? How does the impedence work in that scenario?

Also - why run bare wire to post if leaving cables hooked up? So they don't work loose? So the jack doesn't lose tension?


I may be a New Hampshire boy but I'm not completely stupid (above questions notwithstanding). Everyone thinks one rack will be too bloody heavy and you're all probably correct. I think the two as you've laid out may well be the hot setup. Being the guy hauling the shit, setting it up, running sound and playing guitar makes gigs a less than relaxing experience sometimes. I'm looking to cut down on the time involved in set up.


lou

 

[easychair]

LOL. I was referring to the legendary independence and stubborness of you New Hamphire people, not your intelligence.

Questions - How do you run two speakers/outs off one side of the amp? Splitter? How does the impedence work in that scenario?

You can stack banana plugs, for one option. If you use speakons or 1/4", I made a little splitter, someone may make one for sale, I don't know. Now I have a panel in the back of my amp rack that has XLR and 1/4" jacks and speakons. These run to the inputs and outputs of my amps and crossover. Easier to plug in, and saves wear on the connectors. I use banana plugs at the amp outs, so I can easily switch to bridge mode, swap polarity, etc. Those are wired to the speakons on the panel. I have a few extra on the panel, and I can stack the banana plugs, run another speakon cable to the other box, and run both boxes from one side.

Impedance is the same as a daisy chain, the speakers get paralleled, so the impedance drops the same way.

Also - why run bare wire to post if leaving cables hooked up? So they don't work loose? So the jack doesn't lose tension?
lou

Both. Banana plugs wear out pretty fast under constant use, I find. Really, I'd probably use crimp-type ring connectors on the wire ends. Much neater, and no chance of a short. And things do come loose. Permanent connections can be a pain, though, especially in those emergency situations when you need to rewire everything. Bananas are fine if left hooked up, but I'd clamp the cables to the rack for strain relief, they will stay hooked up better during transit, and also in those times when you give it a little tug to see if maybe it will stretch that little tiny bit more that you need.

Banana plugs also offer more flexibility, as you can remove them quickly if you have to. You may want to stay with them. That's why I dig the little panel. I get the benefits of bananas without most of the hassle. And I don't have to go digging deep in the rack to hook up the crossover. And if you don't use speakons at all, the panel could just as easily be loaded with binding posts or 1/4" speaker jacks. Labelled well, of course!!! Since you want to leave your speaker cables hooked up, you could just go with an input panel, or a few short jumpers to your crossover.

The panel isn't necessary, for years I just had short cables that came to the back of the rack for my x-over, all labelled, and 1 foot banana-speakon adapters. Everything was clamped to the side of the rack for strain relief.


I made an assumption about the SP7G that was half-right. They are 4 ohm boxes. I assumed that when bi-amped, both the highs and lows would be 8 ohms. The highs are, but the lows are 4 ohms. Running those boxes bi-amped with one amp would mean that the low side would be at 2 ohms. One amp would get you by, but two would be better. Even though most amps can handle 2 ohm loads, 4 is a lot less stress. Gives you the option of stereo, as well.

 

[Sky Blue Lou]

Very helpful - thanx again. I'm gonna go over all this with my partner in crime and do some heavy digesting.

lou