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Ohms FAQ
- Thread starter IvanMike
- Start date
Awesome thread! Just what I was looking for. I haven't seen my specific problem addressed here. forgive me if it has been done.
Behringer 3000T amp 300 watt 4ohm minimum load
Steelsound 1 x 15 8ohm
Steelsound 2 x 10...heres the problem. I have two 8ohm 10" woofers that i want to put in this cabinet. How can i wire these to get the most of my setup? Series will give me a 4ohm load, parallel will give me a 16ohm load.
Help!!
Behringer 3000T amp 300 watt 4ohm minimum load
Steelsound 1 x 15 8ohm
Steelsound 2 x 10...heres the problem. I have two 8ohm 10" woofers that i want to put in this cabinet. How can i wire these to get the most of my setup? Series will give me a 4ohm load, parallel will give me a 16ohm load.
Help!!
Im not sure what you mean is the 2x10 an 8ohm cabinet that you want to put a further two single 10" speakers into? Each extra 10" being rated 8ohms?
What ever way you wire it make sure that you end up with above the 4ohm min of the head over all.
What ever way you wire it make sure that you end up with above the 4ohm min of the head over all.
the only way you can wire those speakers on their own is in series so you get 16 ohm resistance on the 2x10 cab. Then when that cab and the 15 are paralleled together that will give you an over all rating of 5.333333 Ohms.
Thats above the minimum requirement of 4ohms for your amp which in theory is ok.
However because the impedances of the cabs are different I believe that the 1x15 cab which is half the impedance of the 2x10 is going to get twice the power sent to it by the head. As opposed to having two 8ohm cabs in parrallel in which case power will be split evenly between the two.
Also the because the overall impedance is slightly higher your going to get slightly less wattage out of your head although. I couldnt say how much less though.
Mismatching impedances like that may also cause problems with the head. Again i'm not 100% sure on that so maybe you could do a search on the subject
Also you have series and parrallel mixed up in you post so just to be certain.
Thats above the minimum requirement of 4ohms for your amp which in theory is ok.
However because the impedances of the cabs are different I believe that the 1x15 cab which is half the impedance of the 2x10 is going to get twice the power sent to it by the head. As opposed to having two 8ohm cabs in parrallel in which case power will be split evenly between the two.
Also the because the overall impedance is slightly higher your going to get slightly less wattage out of your head although. I couldnt say how much less though.
Mismatching impedances like that may also cause problems with the head. Again i'm not 100% sure on that so maybe you could do a search on the subject
Also you have series and parrallel mixed up in you post so just to be certain.
Thank you so much for the feedback. I appreciate it. Now I have a much better idea of what I'm doing here.
I suppose if I just get a pair of 4ohm (each) 10" woofers wired in series, that would solve that problem too.
i'll let you know how it works out.
I love this place!
I suppose if I just get a pair of 4ohm (each) 10" woofers wired in series, that would solve that problem too.
i'll let you know how it works out.
I love this place!
I know this has been asked several times, but not being an English native speaker, some of the expressions seem to escape my understanding...
I have an Aguilar DB750 amp and an 8 Ohm Eden 210 XST cab. I'd like to buy an Eden 212, but the only one I can buy around here is a 4 Ohm version.
That leaves (or, as I'm before purchase, WILL leave) me with an 8 Ohm 210 and a 4 Ohm 212. The DB750 can handle 2 Ohms so I guess it can handle 2.xx (I forgot the exact value) Ohms that result from connecting paralelly these two cabs. This is where my English is inadequate...
Does parallel mean connecting each cab to a separate output of the amp (one cab to one amp output and the other cab to the other)?
Is it advisable to do this? Both cabs have a 103 dB sensitivity. The 8 Ohm 210 XST is 500W, the 4 Ohm 212 XLT is 400W.
What can I expect?
Thanks!
Gergely
I have an Aguilar DB750 amp and an 8 Ohm Eden 210 XST cab. I'd like to buy an Eden 212, but the only one I can buy around here is a 4 Ohm version.
That leaves (or, as I'm before purchase, WILL leave) me with an 8 Ohm 210 and a 4 Ohm 212. The DB750 can handle 2 Ohms so I guess it can handle 2.xx (I forgot the exact value) Ohms that result from connecting paralelly these two cabs. This is where my English is inadequate...
Does parallel mean connecting each cab to a separate output of the amp (one cab to one amp output and the other cab to the other)?
Is it advisable to do this? Both cabs have a 103 dB sensitivity. The 8 Ohm 210 XST is 500W, the 4 Ohm 212 XLT is 400W.
What can I expect?
Thanks!
Gergely
I think that your best bet is to e - mail aguilar and ask them if their head will handle the mis matched (8ohm + 4ohm) impedances. I would imagine that it would be ok.
The value of 4 ohms and 8ohms in parallel is 2.66667
1/(1/4+1/8) = 2.67 ohms
Again there most likley would be more power coming out on cab than the other because of the differenet impedance values
Parallel is a method of connecting anything electical such as resistors, capacitors, speakers etc.
For example a speaker has two wires coming off it. A red wire (positive) and a black wire (negative).You can see this in lot of combo guitar amps and in cabs with holes in the back that let you see the speaker from behind. If you were to connect the speakers in parallel the two red wires would be connected together and the two black wires would be connected together. These red and black wires are then connected to the signal coming from the amp.
Connected in series would mean one red wire from one speaker is connected to one black wire from the other speaker. The left over red and black wire is connected to the signal coming from the amp
When you use two cabs and one head they will always be connected in parallel and it doesn't matter how you connecet them
wire from head to cab + a second wire from head to a second cab
OR
wire from head to cab + wire from first cab into second cab
both connections will be parallel connections. All the connecting in parallel is done inside the head all you have to do is plug in the cabs
The value of 4 ohms and 8ohms in parallel is 2.66667
1/(1/4+1/8) = 2.67 ohms
Again there most likley would be more power coming out on cab than the other because of the differenet impedance values
Parallel is a method of connecting anything electical such as resistors, capacitors, speakers etc.
For example a speaker has two wires coming off it. A red wire (positive) and a black wire (negative).You can see this in lot of combo guitar amps and in cabs with holes in the back that let you see the speaker from behind. If you were to connect the speakers in parallel the two red wires would be connected together and the two black wires would be connected together. These red and black wires are then connected to the signal coming from the amp.
Connected in series would mean one red wire from one speaker is connected to one black wire from the other speaker. The left over red and black wire is connected to the signal coming from the amp
When you use two cabs and one head they will always be connected in parallel and it doesn't matter how you connecet them
wire from head to cab + a second wire from head to a second cab
OR
wire from head to cab + wire from first cab into second cab
both connections will be parallel connections. All the connecting in parallel is done inside the head all you have to do is plug in the cabs
ERIC31 said:Thank you so much for the feedback. I appreciate it. Now I have a much better idea of what I'm doing here.
I suppose if I just get a pair of 4ohm (each) 10" woofers wired in series, that would solve that problem too.
i'll let you know how it works out.
I love this place!
You would be better off getting 2 16 ohm 10" drivers, and wiring them in parallel. That will give you a total impedance for that 2x10 cab at 8 ohms.
Then you can use the 1x 15 8 ohm cab on your second
amp speaker output (if available) or your 2x10 line out,
which is usually wired in parallel.
This will give you a final total impedance of 4 ohms, and all
the drivers will be in phase.
The 1x15 cab will receive 1/2 the power, and the 2 x10
will receive 1/2 the power. ( The 10's will receive 1/4 of the total power output each)
This is the most elegant solution to the rig that you propose,
satisifes all the impedance matching issues and has the most
versatility.
Glad you love this place ....
Well I've tried to hook this thing up but it's not working. 2 x 10 is much more complicated. Probably because I don't know what I'm doing! LOL I'm taking it down to my local music shop to have it wired up by a pro so I'll have no problems.
Question:
How is it that four 8 ohm speakers, can be wired for a total impedence of 8 ohms? I have a Laney R410 with 8 ohm Celestions, and I just don't understand how that works.
Also, is it possible to wire these (four 8 ohm) speakers for a total impedence of 4 ohms? What's the best way to do this?
Thanks.
How is it that four 8 ohm speakers, can be wired for a total impedence of 8 ohms? I have a Laney R410 with 8 ohm Celestions, and I just don't understand how that works.
Also, is it possible to wire these (four 8 ohm) speakers for a total impedence of 4 ohms? What's the best way to do this?
Thanks.
needmoney said:
You get 8 ohms out of four 8 ohm speakers by using a series-parallel connection. Wire one pair in series for a total of 16 ohms, then do the same for the other pair. Wire the two 16 ohm pairs together *in parallel* for a total of 8 ohms again. You could also do it the other way around if you wanted.
You can't really wire four 8 ohm speakers together to get 4 ohms. You can get 2 ohms (all parallel), 8 ohms (series-parallel), or 32 ohms (all series). You could get some inbetween impedances too, but only by doing something screwy that wouldn't make sense, like wiring three speakers together one way, and then wiring this triplet to a single speaker another way.
Richard Lindsey said:
Building on this.... back 'in the day' when the fretless stereo chorus sound was in vogue, we took 4x10 8 ohm cabs with 4 8 ohms speakers and rewired/added an additional input jack so that you could have two separate 4ohm pairs of speakers in the same cab.... just hook up a stereo power amp and a two channel preamp and off you went.... pretty cool!
needmoney said:
Here is a typical series/parallel wiring diagram.
You can remove the piezo and output for simplicity.
Can I play too? I went back and skimmed through the thread and saw stuff similar to what I'm about to ask, but not exactly. Forgive any redundancy...
From page 1, IvanMike said:
Exactly my current setup:
T-E GP12, Series 6 (says minimum load 4 ohm on the back) -> Ashdown Mini 15 (300w @ 8 ohm) + T-E 1048T (300w @ 4 ohm).
So, for 4 years now, I've been running a 2.67ohm load into a minimum 4ohm amp.
So far, so good.
Anyway, I'm looking into a new 2x10 cab and it's rated at 8ohm. Run that with the Ashdown for another 8ohm and I get a load of 4 ohm, yes? Now, this 2x10 is rated at 700w. If I'm running it at 4 ohm, is it putting out 350w? So confusing!!
Since 4 ohm the minimum my T-E wants, and since it's more than it's used to, what will happen to my sound? Will the head run more efficiently and therefore hook me up with more wattage?
Thanks for your expertise!
From page 1, IvanMike said:
Exactly my current setup:
T-E GP12, Series 6 (says minimum load 4 ohm on the back) -> Ashdown Mini 15 (300w @ 8 ohm) + T-E 1048T (300w @ 4 ohm).
So, for 4 years now, I've been running a 2.67ohm load into a minimum 4ohm amp.
So far, so good.Anyway, I'm looking into a new 2x10 cab and it's rated at 8ohm. Run that with the Ashdown for another 8ohm and I get a load of 4 ohm, yes? Now, this 2x10 is rated at 700w. If I'm running it at 4 ohm, is it putting out 350w? So confusing!!
Since 4 ohm the minimum my T-E wants, and since it's more than it's used to, what will happen to my sound? Will the head run more efficiently and therefore hook me up with more wattage?
Thanks for your expertise!
If I understand you correctly, The TE head will put out whatever it is rated @ 8-ohms or 4-ohms. The speaker cabinets do not put out anything, those numbers are just their power ratings of the max they can handle.lildrgn said:
Yes you were running your head at a 2.67-ohm load, if your head has a minimum load of 4-ohms you were below that and the manuf. doesn't recommend it. 'nuff said.
If your head is rated something like (for example) 220watts/@8-ohms and 400watts/@4-ohms and 500watts/2.67-ohms then that is what the amp is pushing out at those loads. and that load is divided between cabs.
It gets tricky here when different ohm cabs are mixed together. Think of it this way. If you are running one 8-ohm cab and one 4-ohm cab the amp will *see* them as 3 4-ohm cabs. The one 4-ohm cab and the one 8-ohm (2x4-ohms) cab. The power is then divided equally among the 4-ohm cabs, the 8-ohm cab which is seen as 2 4-ohm cabs will get twice the power. 500 watts divided by 3 = 166 watts, each 4-ohm segment gets 166 watts. The 4-ohm cab gets 166 watts and the 8-ohm cab gets 332 watts (2x166)
I may be wrong, and I am open to correction, but that is my understanding of mixing different ohm cabinets. It is a lot simpler to figure the power dispersion when mixing cabs of the same ohm-load, the power is just equally divided among the number of cabs.
Your TE would run cooler than your previous setup with a 4-ohm load into 2 8-ohm cabs in parallel. The power would be equally disributed to both cabs. If (for example) your head is rated at 400watts/@4-ohms, then each cab would be getting 200watts.
lildrgn said:
Hope I can answer that a little bit.
A solid-state amplifier produces power by supplying voltage and current. (P=VI) Let's first look at the voltage side of the equation...the maximum voltage that an amp can deliver is predetermined by the design of the amp's internal power supply, called rails--there's a +DC rail and a -DC rail. These rails supply the output transistors, so the output transistors can't deliver more voltage than the voltage on the rails.
The other half of the equation is current. This is where the speaker load affect everything big-time. As the speaker's impedance drops, the current demand increases. Sure the amp may have enough voltage, but if the transistors can't supply enough current, they will overheat, their power production will drop, and they may fry. So at 2.67 ohms you may have been in that "gray zone" where the transistors have not yet fried, but they may not be operating as efficiently as they would have been in a 4 ohm situation.
Let me take a stab at this. If you have a 60 w lamp in an outlet, and you plug in a 2nd 60 w lamp, what happens? Each lamp gets 60W, total 120W.nashvillebill said:
This is what the power amp TRIES to do with the extra cab, but it can't maintain the power supply voltage with the heavier load, it "sags" or "droops" so you don't quite get double the power by adding the 2nd cab of the same impedance.
If you were using a really tiny extention cord so there would be a similar voltage drop so you could end up with 60W going to 1 lamp, but when the 2nd lamp is added, the voltage sags from 120 V to maybe only 110 V and the 2 lamps used together don't quite end up with 120 w total anymore. Power has been absorbed by the cheap wire, wasted.
Also what happens when using too small wire to hook up your speakers, by the way.
Randy
not sure if anyone is able to help me out with this...
i've got a 1x15 speaker cab with two jack inputs in the back, its got a 4 ohm, 300w, celstian that i put in when i use to run a 4 ohm head.
what i would like to do is split the line from my bass and put it through two 8 ohm heads; a 250w bass head (for bass) and a 100w valve guitar head (for fuzz), then blend them both in the speaker.
the question is... can i run two 8 ohm heads into one 4 ohm cab? what will happen, will it end in tears?
cheers me dears.
i've got a 1x15 speaker cab with two jack inputs in the back, its got a 4 ohm, 300w, celstian that i put in when i use to run a 4 ohm head.
what i would like to do is split the line from my bass and put it through two 8 ohm heads; a 250w bass head (for bass) and a 100w valve guitar head (for fuzz), then blend them both in the speaker.
the question is... can i run two 8 ohm heads into one 4 ohm cab? what will happen, will it end in tears?
cheers me dears.
