basic question about speaker/ohm set up
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Posted on Dec 11, 2008 07:21 am
david jackman
Member Since: Dec 07, 2008
Just a quick question about my potential set up.My powered mixer will send 300w to the mains when powering 4 ohm load.I currently have a 8 ohm speaker on each side. I understand that running 2 8 ohm speakers on the same side will give me the 4 ohm load.(I have already acquired the two extra 8 ohm speakers) My question is this, if I put a 1/4 jack spliter in the mixer output (ie. the right channel) and run 2 speakers cables from it , will this give me the 4ohm load for that channel? Is this aviable option or there other options? There are no outputs on the speakers , so they can't be connected that way.Thanks in advance for any advice you can offer.
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Dec 11, 2008 07:56 am two eight ohms speakers will give you a 4 ohm load if they are run in parallel, not in sequence...if memory serves me correctly, the way you mention to run it (with the splitter) would be parallel and give you the 4 ohm load.
Wait for Rob Stemple, he's good on this sort of thing and around daily.
Dec 11, 2008 06:06 pm dB has it right. A splitter is in parallel. And yes, you will be in a 4 ohm load.
The only thing that you did not mention, is how many watts each of your speaker are?
At 300 watts, it really doesn't matter all that much, but, even still. You need to make sure that the total of the two speakers is close to the 300 watt limit.
So, 2 150 watt 8 ohm speakers is kind of what your looking for.
Dec 12, 2008 07:42 pm Thanks for your advice guys.Rob, one speaker is 125 w and the other is 100w.Would this be a reasonable set up for the 300w power output? Maybe I wasn't clear, there will be 150w to each side.Will I still be ok?One other quick question.I can split the power so that 150 watts mains/150 watts monitors.My basic understanding tells me that my mains will receive 75 watts to each side.In this setup can I still use the splitter and my speakers as mentioned previously.Thanks,David.
Dec 12, 2008 09:56 pm I'm sorry, you lost me a little here.
Usually when you are given as amps rating, it is per side. So, 300 watts @ 4 ohms per side of the amp.
Now, these are RMS ratings. Or continuous power. Peak, is another rating that they give. And the peak will always be above the RMS value.
Now, wattage is just how much current an amp is pushing down the line. It is a constant. So, 300 watts will be coming down the line when you have the proper ohm load, and are at the input sensitivity level.
From here, you want speakers that can absorber the amount of wattage that the amp is producing. This is where I mentioned the two 150 watt speakers for the example.
Wattage, can not be split. It can only be absorbed.
This is why yo want to put the proper amount of speakers on an amp to to give it the ohm load, and speaker wattage.
Now, you can use series/parallel connection to get all of the ratings that you need.
If you need to know how that is done, I can give some examples.
I hope this is of help to you.
Dec 13, 2008 06:21 am Rob,sorry for the confusion.Here are my specifics:
- samson tm300 powered mixer producing 150 w per side at 4 ohms.My understanding is that at 8 ohms this power output is seriously reduced,hence my desire to get the two speakers on each side.It is not a powerful unit and I am trying to get whatever power it has to offer.Are the potential gains worth the hassel?
-My speakers are 100w and 125 w continous.
-If this unit is used in the split monitor/main mode the power output is cut in half,right?Am I then correct in saying that the mains will get 75w per side at 4 ohms?
Thanks again for all your advice. david
Dec 13, 2008 11:23 am Oh, I see where the confusion is.
your amp is a stereo amp. When it says Monitor/Mains, it is referring to where it is picking up the signal from.
So, in Mon/Mains, one side is getting the signal from the aux sends. The other from the Left/Right (Summed together).
The power output is still the same for each side. 150w @ 4 ohms. And the speakers that you have, match the ratings very well. Going above the amps output rating for your speakers, by only a small amount, is just fine.
Going to far above will out an undo strain on the amp. You would need more power just to move the speakers then the amp can produce. Being that all speakers have a minimum wattage requirement.
Running the mixer in Main mode, will give you a true Left/Right mix. Running in Mon/Main will give you one mix of monitors, and one summed mix of the Left/Right out.
monmixrIf 50hz 60 will kill ya.Member
Since: Jan 08, 2009
Jan 08, 2009 12:18 am Ultimately you would want to have power at twice the rating of your drivers, this gives you headroom.However, with todays hi watt drivers, this can get very expensive very quickly. Driving a 150 watt driver with a 150 watt amp gives you very little headroom. You are going to damage your drivers much faster by overdriving your power and sending square waves to your drivers than you are by "overpowering" them. Put a little wattage in the cottage...give yourself some headroom. In the rig you have described you have to be very careful not to overdrive your power. overdriving or "clipping" is actually cutting the tops and bottoms of the sine wave off creating a square wave, and that is something that drivers hate.
