Mixing 4 ohms & 8 ohms Speakers In A Daisy Chain ?
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Posted on Aug 02, 2010 07:51 am
Hatch
Member Since: Aug 01, 2010
Hey All, I'm New To The Scene & Have A Few ?
Most Of My Speakers 8 ohm 15" With A Horn Cabinets, I Do Have Some 4 ohm Double 15" With A Horn Cabinets As Well..
All My Amps Are Rated For 2 ohm, 4 ohm, & 8 ohm Loads, The Last Gig We Did Off Of One Of My 2500 Watt Amps Each Channel I Daisy Chained 1 - 4 ohm Cabinet With 1 - 8 ohm Cabinet On The End, Not Sure If That Is The Proper Way To Daisy Chain ? I Know If You Daisy Chain 2 - 4 ohms The Load Changes To 2 ohms, And If You Daisy Chain 2 - 8 ohms The Load Changes To 4 ohms, So The Big ? Is If You Have 1 - 4 ohm + 1 - 8 ohm Will = 2.something ohms Load ? Or Will It Make It = 6 ohms Load ? On Another Note Would It Make Any Difference If You Had The 1 - 8 ohm Cabinet First Then The 4 ohm Cabinet On The End Of The Daisy Chain ?
Yet Another ? Would This Set Up Work Better If Off One Channel I Daisy Chained 2 - 4 ohm Cabinets To Get A 2 ohm Load, Then Off The Other Channel Daisy Chain 2 - 8 ohm Cabinets To Get A 4 ohm Load ?
Okay I Have Four Amps Altogether 2 - 2500w. I Use To Drive The Main's (6 - cabinets totaling 8 - 15" woofer/horns & 2 - 15" sub's), 1 - 500w. I Use To Drive The Lead Singer's 2 - 12"/Horn Monitors On One Channel (Off aux - 1 on mixer), Then The Other Channel I Drive 2 - 12"/Horn Monitors For The Drummer (Off aux - 2 on Mixer), My Mixer Is A Non-Powered Eurodesk SL2442FX-Pro, My ? Here Is I Have Another Power-Mixer 500w. & 2 - 15"/Horn Monitors I Want To Use For The Guitar Player & Bass Player This Mix I Want To Send Both Of Them Will Be The Hole Band (or The Main Mix), The Power Mixer All I'm Using It For Is The 500w Amp., Would It Be Better To Daisy Chain Off The The Main Amps To One Of The Mono 1/4" TRS Line-In Jacks/or XLR, Or The Aux 1/4" TRS Line-In Jack, Or One Of The Effect's 1/4" TRS Line-In Just For The Main Mix Signal ?
Or Would It Be Best To Use The Other Aux. F-1 & F-2 Off My Main Mixer Just For The Main Mix Signal ?
Hey Thanks In Advance For Some Help & Getting Me Going In The Right Direction On Everything For That Perfect Sound !!
Catch Ya Later, Hatch
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pjkPrince CZAR-mingMember
Since: Apr 08, 2004
Aug 02, 2010 08:21 am Wow, you really like Capital Letters. It makes it hard to read, and is considered bad form to use unusual capitalization. Makes it difficult to read.
But anyway, welcome to the HRC. I'm not an expert on live sound, but if you have 2 speakers; 4 ohm & 8 ohm, hooked together, either parallel or series, then you're not going to hear the 8 ohm. Instead, you'll just throw off the impedance the amp sees, either making the ohms: 2.6 ohms, or 12 ohms. Both aren't great. Plus, the 4 ohm speaker will be doing all the work, so most of the power will only go to that speaker. Not good.
I'm not sure what the daisy chain jacks do for a chain of speakers, either connecting them in parallel, or in series. I'd check to be VERY sure before I set them up again.
You may want to get yourself a meter, so you can check the resistance of your speaker chain before you make something bad happen.
Here's a nifty page on calculating, and figuring out speaker impedance matching, calculations, etc. It's for car audio, but the basics are the same: amp -> speakers
www.bcae1.com/spkrmlti.htm
In a nutshell, spks hooked up in parallel cut down the resistance, where spks hooked up in series add up the resistance. If the spks resistance is equal, then it's done in nice even chunks, but if the speakers are not matched, then funny math can apply to parallel connections. Series connections keep adding up.
I'm thinking, after I read the above page and figured out impedance matching, is that I would put the 8 ohms together on one amp, and the 4 ohms together on the other amp. Then you don't have any mismatches. But I'd have to get more detailed to figure it all out.
I'm sure Rob will be along before long, and give a more professional opinion on matters.
Aug 02, 2010 06:34 pm Hey Hatch! Welcome to the HRC from here as well.
First off, I need to know what the rms value of the wattage is of your speakers. If your pushing 2500 watts per channel of you amp, then you have a very hefty amp, and you could be cooking the speakers. Now, you do want just a little more wattage to be able to push above the rms value, but, not an excessive amount.
Second, pjk is correct in the total ohm load that you will have by connecting a 4 and an 8 ohm speaker in the same signal path. It's very simple arithmeticians to find what the total ohm load will be.
Ohm X Ohm
------------------- = Total Ohm's
Ohm + Ohm
So, in your case, it's 4 X 8 = 32. Then 4 + 8= 12. 32 / 12 = 2.6
Now, for the total wattage. Here, this is really simple. You just add the wattage together. And that's it! So, Wattage + Wattage. And this will tell you the total amount of wattage that your speakers can soak up. Now, just in case your amp is 2500 watts in total, meaning bridge mono @ 2 ohm load. That means that each of the channels will be considerably less when running in a stereo mode. You will need to look back over the spec sheet for your amp to see what the rating is for this. You just need to look at the stereo mode @ 2 ohm rating. And now you will know how much your pushing at max for each channel. Once again, bounce this off of the Wattage total for your two speakers.
Now, all speaker manufactures hook all of the jacks on the back of the speakers in parallel. So, when you daisy chain, you are hooking everything in parallel.
As for how to give the the other members of the band a FOH mix........... Unless you have another 31 band EQ laying around that you can hook in, your just asking for problems. There is not an additional EQ on a powered lixer that you would be able to access. So, you would just be creating a feedback situation. Using the same little 10 band EQ that is there already for both FOH, and monitors will lead to some very crappy sound out in the house. Being that you will have to hack just about everything to make the monitors stable.
The best way to do so with your set up is to split the signal out the back that goes to your Left and Right mains. From there, take it to some sort of graphic EQ, and then to a power amp. Now you can lower the total gain of the EQ, or turn back the input sensitivity knobs on the amp, to control the volume on stage. And still give the two members the FOH mix that you want.
HatchMember
Since: Aug 01, 2010
Aug 02, 2010 07:36 pm Awesome I thank you both, I will work on the cap's thing, it's a old engineering habit sorry..
Put ya that all helps alot, on the daisy chaining & getting the 2.6 load will it make a difference which comes first in-line, like 4 ohms + 8 ohms or 8 ohms + 4 ohms just on a wear & tear aspect ? or is that where rms value comes into play ? I'm guessing the high of the two rms would be first in-line ?
And my amps are 2500w. total, @ 1200w. per channel @ 2 ohms, I have never bridged any of the amps ? should I, another thing while talking amps, can you have different loads off each channel ?
I'll get a 31 band EQ to add to the mix, thanks, would adding a cross/over help in any way ?
Check ya'll later, I'll Be Back , Hatch
Aug 02, 2010 09:48 pm In parallel, it doesn't matter. It see the speakers in the same way. One big resistor. So, position doesn't mean anything to the amp.
The rms value comes into play with the 1200 watts per side of the amp. You need to make sure that the speakers can absorb the 1200 watts the amp is kicking out. Lets say that your speakers can take 1000 for your 4 ohm speakers, and 600 with the 8 ohm speakers. The total wattage that your speakers can take at that point is 1600 watts.
Well, with your amp only outputing 1200 watts, your under powering your speakers by 400 watts. This can lead to a situation called "Square Waving". Square waving is caused by the speaker being able to handle the wattage being thrown at it. So, no distortion. This leads to pushing the mains fader up higher to get a desired volume. Once the amp goes into continues clip, (Solid Red for more then a second or two.) a square wave can develop. Which will cause a great deal of heat within your system, and it will destroy all in it's path!!!!
Ideally, you want your speakers rms total to be around 1100 - 1150 for your amp. This will prevent square waving, and will allow your system to live a long and happy life.
As far as adding a crossover, that's up to you. It will give your system some more headroom. So, you can get that extra +3 dB out of it when you really need it.
