mackie amp with wedges

[Scott Brochu]

I just finished 4 w10's and am hooking up to a 1000 watt mackie amp. It is 8 ohms and 2 channels. If I hook up 2 per channel than am I dealing with 2 ohms per speaker? and is this good? If I get a bigger amp like Behringer 1500 and do the same would that make it louder or blow the speakers?
Thanks

[novasak]

What do you mean "It is 8 ohms and 2 channels"? Each amp channel is 8 ohms? What model amp is it?

over all, for most 2 channel amps, you should have no problem running 2 wedges on each channel. I would not run all 4 on a single channel though, and never in bridge mode.

[Scott Brochu]

I thought it was 8ohms. Maybe bridged.
So it might be 16 ohms 8 per channel?
If that is the case it is 4ohms per cab if i run 2 on each channel.
Just trying to get more out of it for my leed singer. I should'nt run more watts into it...should I?

It's an older amp I'll try to find the link to it.

[David Carter]

Normally, amp ratings are listed per channel. For example, the Mackie M2000 is listed on mackie.com as 400W/channel @ 8 ohms, 650W/channel @ 4 ohms, 1000W/channel @ 2 ohms. For this particular amp, this means that you can run a 2 ohm load on each channel (although not advisable). That would mean that you could connect all 4 of your WH10's to one side of the amp (again, not advisable) and they'd be getting 1000W. Two on each side would be a 4ohm load on each side which would result in 650W/side.

So, is your quote of 8 ohms and 1000W a per-channel rating? Does it handle a 4ohm or 2ohm load? If so, what's the power rating to those loads? If it'll handle 4ohms per channel (which just about any power amp these days will), you're fine connecting 2 WH10's per side.

[novasak]

Looking at most Mackie amps, even discontinued amps, all are capable of running at 2 ohms per channel.

Your best/easiest option, IMO, is to run 2 wedges per channel. This will make a safe 4 ohm load and, hopefully, provide plenty of power.

[Scott Brochu]

http://www.mackie.com/pdf/FRSeries_OM.pdf
Mackie M1400i FR series
This is the one but mine is a lot older.
it says Mono bridge 1000w at 8ohms
stereo 500w/500w 4 ohm load

So does that make it 2ohms per cab and 4 ohms per channel? If I run 2 off each channel?
I also was messing with the back of it and there is a switch that is the constant directivity. It is on 4.5khz (straight up) to the left it can go to 2khz and 6khz all the way clock wise.
Also switched the dial to monitor (100hz) instead of 80hz what it was set at. This must be the cross over dial of some sort. There is a limiter on it and it is on.

[David Carter]

So does that make it 2ohms per cab and 4 ohms per channel? If I run 2 off each channel?

Your cabs are always going to be 8ohm cabs because they have 8ohm drivers in them (I'm assuming). If you connect two of them to a single amp channel, the two 8ohm loads paralleled together put a 4ohm load on that amp channel. Same for the other amp channel. So, doing it that way, each amp channel will put out a max of 500W to the pair of WH10's connected to it.

[Scott Brochu]

Thanks David.
I used the default driver in Leland's kit. If memory serves me right, than the driver is the Beta 10 which I think is a 8 or a 16ohm driver.
Let me just say, Hooking these up to the amp and hearing them I all ready notice a difference in the sound from the 15" Behringers we used. They sound full and rich but very exact on the highs (thats the only way I can explain it)
I am letting another band try them this Fri and they will be up against some 12" Yamaha wedges.
They have Behringer 1500's now for the 4 they got one per channel, which is what...750watts a channel?
So if I did this to the wedges I will probably blow'm, right?
I think I will tell him to hook....wait I will hook up the wedges 2 per channel of 1amp.

[Gregory East]

I can see you are a bit out of your depth so it's good that you're asking questions.

Sorry, I don't know what a behringer 1500 is exactly. Conventionally it would be 750W a side into 4 ohms. Or possibly 1500 into 4 ohm when bridged.

So I'm pretty sure it is capable of blowing up 2 wedges per channel if you could cope with them going full blast in your face. Reading the reviews I doubt anyone would be needing to try it up that loud. I'd be surprised if they need any more than 150W each to be crazy loud. That might be close to the limit of the drivers anyway.

Your real problem is a lack of comprehension of power and speaker loadings. Amps are rated by how much power they can deliver to a given minimum load. More speakers in parallel lowers the load on the amp so it puts out more power. I think you have that bit down.

Too many speakers overloads the amp.

Too much amp overloads the speakers.

You could put a limiter on the amp but that's a whole lot more learning to be done. Have to start talking in Volts!

[Scott Brochu]

Ya, I am in my learning yrs of this trade.
I didn't even have a clue about these things a while ago because everyone set it up for me in my last band. It is only when I swaped bands and needed subs is when I looked here and got into it.
I am a Dietetic Technician by day.

[LelandCrooks]

I am a Dietetic Technician by day.

Teach me to keep 25lbs off and I'll teach you electricity.

[David Carter]

Ya, I am in my learning yrs of this trade.
I didn't even have a clue about these things a while ago because everyone set it up for me in my last band. It is only when I swaped bands and needed subs is when I looked here and got into it.
I am a Dietetic Technician by day.

Don't worry. You're not alone. I didn't have a clue two years ago when I first showed up here wanting an affordable option for a bass guitar cab. I still pale in comparison to many around here, but they've taught me an awful lot! There is hope...

[Scott Brochu]

I am a Dietetic Technician by day.

Teach me to keep 25lbs off and I'll teach you electricity.

DEAL!

Stay away from snacking at night and exercise thats it, for 9 out of 10 people.

[Gregory East]

I work at night, never had a problem with weight gain until I stuffed my ankle. Staying away from icecream and beer helps. These are not snacks but essentials of life

Back to amps and speaker loads.

An amp is happy until you try to suck too much power out of it. A speaker is happy until you put too much in.

The load per channel is the inverse of the sum of the inverses of the cab impedances. Eg 1/8 + 1/8 = 1/4 then 1/(1/4) = 4 ohm load a safe load for most amp channels, there are usually two channels per amp.

These horn loaded speakers get a bit tricky when it comes to how much power they will take so it pays to f.t.p.

[mattaudio]

Another reason to have one or two wedges per amp channel: You get more monitor mixes. If you put four on one channel or bridged, you get the same mix in four wedges, which sucks. The best way to make musicians happy, short of in-ears, is for each to have their own mix and wedge.