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Author Topic: Confused about powering 8 Ohm Speakers  (Read 4459 times)

Al Limberg

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Re: Confused about powering 8 Ohm Speakers
« Reply #20 on: October 04, 2005, 10:18:22 am »

Justin, you seriously need to go to the study hall and learn how speaker loads combine when wired in parallel or series.  This isn't rocket science and it becomes more apparent with every post that you haven't grasped this relatively elementary audio concept.  

Al
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Bud Bolf

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Re: Confused about powering 8 Ohm Speakers
« Reply #21 on: October 04, 2005, 07:35:55 pm »

Justin,
Your Mackie mixer the 808m the M stands for Mono, so you do not have a Pan, because the Left & Right is summed together.
If it was Stereo it would be a 808S.

Because it is not a Stereo Powered Mixer you have what they call the Main and the Monitor Power Amps. However with the Power Amp routing switch you can select how these Power Amps are used, either Main/Monitor setup or a Main/Main setup. This button is located to the right of the last Channel strip's XLR - 1/4" Inputs right above the EFFECTS 1/4" Send/return. Do you see it?
With the switch in the UP position, it routes to Amp1/Main and Amp2/Main

Now in the Back of the Mixer, plug one of your JBL's into
Power Amp1/Main Speaker out, pick either 1/4" jack, their Paralleled together.
Now the part that your NOT GETTING, Plug the other JBL into one of the 1/4" jacks above the markings for, Power Amp 2 / Monitor!
You now are using both Internal Power Amps and you have 300Watts per Speaker Cabinet.

Turn on the Mixer and your good to go, Mix as you usually do.
You should notice a difference though with the extra Power/Voltage being applied to your Speakers.

The Manual is not clear if the Monitor 9 Band EQ will now effect the JBL that is now plugged in to that Power Amp output, but I would think that it should. Move the Sliders and see if it effects the JBL Speaker, if it does, then you now have a seperate
EQ for each Cabinet. Also if it does, make sure that the 75Hz Rumble Reduction is set the same for both.
That's about it.

  Later,
    Bud
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Justin Philip

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Re: Confused about powering 8 Ohm Speakers
« Reply #22 on: October 04, 2005, 09:58:20 pm »

Bud thanks for helping but I knew all that stuff in your post.

Even though i said i dont have anything plugged into power amp 2, i have a peavey loudspeaker with 15" woofer sittin there which i am planning to plug into power amp 2 to use as a 3rd speaker. the speaker is 300w rms at 4 ohm. and does "ok" lows.

thats why i asked if its better to plug both jbls into the outputs of power amp 1 or run one into an output and plug speaker B into speaker A.
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Andy Spalla

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Re: Confused about powering 8 Ohm Speakers
« Reply #23 on: October 04, 2005, 11:54:15 pm »

In that case, I would put both speakers on amp 1. Your JBL speakers would get 225w per cab. Very underpowered. Whatever this Peavey subwoofer is, it may need an active crossover, which I don't beleive you can do on the 808.

Oh how I hate those 808s...
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-Andy Spalla
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Bud Bolf

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Re: Confused about powering 8 Ohm Speakers
« Reply #24 on: October 05, 2005, 11:31:50 am »

 Justin,
 Geeze, everytime we get one step forward,
you change the scenerio of what you want to do.
It's frustrating and hard to keep up!
I'm afraid to ask, what's next? But here goes!!
What's with this Peavey Speaker? Make and Model?
What do you want it to do? Do you have a crossover?
God help us,
  Bud
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Justin Philip

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Re: Confused about powering 8 Ohm Speakers
« Reply #25 on: October 06, 2005, 12:05:57 am »

Bud Bolf wrote on Wed, 05 October 2005 10:31

 Justin,
 Geeze, everytime we get one step forward,
you change the scenerio of what you want to do.
It's frustrating and hard to keep up!
I'm afraid to ask, what's next? But here goes!!
What's with this Peavey Speaker? Make and Model?
What do you want it to do? Do you have a crossover?
God help us,
  Bud


haha. I am sorry man. Brace yourself. Here it goes. DONT GET MAD!

I returned the Mackie 808m. Got a 16 channel behringer (i know, on a tight budget) mixer instead. as far as amp for the 2 jbls..i got a QSC RMX 2450. they push 500 RMS at 8 Ohms per channel. Also got a jbl powered sub at 300 RMS with a built in crossover. So i connected mixer to subs, then line outs to amp and then the speakers. the youth pastor is happy now.  

As far the turbosound issue, i got a pro to come out and look at it. he said bad idea to hang those in the middle of the church. and even if i do delay, it wont sound right. he told me the turbosounds are better than the two yamahas i have right now. (1000w rms at 4 ohms powered by ce4000 - 1200w at 4 ohms)

His advice: take out the Yahamas completely. Run the mains (high/mids only-i have a crossover and 2 jbls for my lows) with the new turbosound, and mount/angle them for the best coverage. power them with my current crown ce4000.(600w @ 8ohm).

Sorry about all the confusion. but forget the whole mackie 808m..all under control now. What do yall think about replacing the yamahas. good idea?
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