Wiring 16ohm speakers for 8ohm? - Gearslutz.com

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25th January 2012   #1
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Wiring 16ohm speakers for 8ohm?

Ok I have a 4x12 cab with 16 ohm speakers, How would I go about wiring these things so that they are 8 ohm? I found this...

Quote:
 Now, if we take a single 8 ohm speaker and attach it to another 8 ohm speaker, we can actually hook it up so that its resistance in ohms can be one of two ratings. If we wire the positive and negative terminals of each speaker together, this is called a parallel connection. Parallel connections reduce overall resistance, and as such the ohmâ€™s rating would be halved to four ohms. What if we add another pair of 8 ohm speakers to the first pair and wire them all together the same way? The second pair of 8 ohm speakers would be of course halved to four ohms. Then, when we wire the resulting two 4 ohm pairs together, this would of course bring the overall final resistance to 2 ohms.
Seems like I could use the same process to make 4x12 16ohm speakers be 4x12 8ohm speakers.

But it makes my brain hurt. Can someone simplify this for me? Or explain it in way I might understand what I need to do?

PS, I also need to add a parallel output to this cab so I can run 2 cabs together. If you think this is an ignorant question, I wont argue with you, I know absolutely nothing about this. But I'm trying to learn.
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 25th January 2012 #2 Lives for gear     Joined: May 2005 Location: Oklahoma City Posts: 1,988 With four 16 Ohm speakers (AND presuming you want the amplifier's power to divide equally among all four speakers), you have three possible choices: 64 Ohms (all four speakers wired in series) 16 Ohms (two pairs of speakers each in series, then each pair in parallel with the other) 4 Ohms (all 4 speakers in parallel with each other) 8 Ohms won't happen. Best, Bri __________________ Brian Roth Technical Services Oklahoma City, OK www.BrianRoth.com
 25th January 2012 #3 Lives for gear     Joined: Dec 2009 Posts: 1,049 Thread Starter 1 Review written Shucks! I'll look at my Head options, see if I can't make it work. I have an 8ohm cab and a 16ohm cab, I want to run them together. What can I do? I can run the 16ohm at 8ohms but lose volume right? Or will I damage something?
 25th January 2012 #4 Lives for gear   Joined: Feb 2010 Location: New Zealand Posts: 1,007 To avoid damaging the amp, the speaker has to be the same, or higher impedance than the amp. Optimum impedance gives a maximum power transfer. Transistor amps are more forgiving than valve amps. To work out the total impedance of the two cabs in parallel, you first multiply the two values (16x8=128). Then divide this by the sum of the two values (128/24=5.33ohms). So, which cab will be louder... The single 8, or the 4 wired as 16....
 25th January 2012 #5 Gear addict     Joined: May 2006 Location: Vancouver Island Posts: 385 You could wire your 16 ohm cab as a stereo 8 ohm cab ...... then you can use both amps with the same 4 x 12 and at 8 ohms ...... you can also add a switch to so you can use it as a 16 ohm mono cab or a 8 ohm stereo cab .....
26th January 2012   #6
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Quote:
 Originally Posted by Minion You could wire your 16 ohm cab as a stereo 8 ohm cab ...... then you can use both amps with the same 4 x 12 and at 8 ohms ...... you can also add a switch to so you can use it as a 16 ohm mono cab or a 8 ohm stereo cab .....
That is an amazing idea. cheers to you!

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8th May 2012   #7
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Quote:
 Originally Posted by Minion You could wire your 16 ohm cab as a stereo 8 ohm cab ...... then you can use both amps with the same 4 x 12 and at 8 ohms ...... you can also add a switch to so you can use it as a 16 ohm mono cab or a 8 ohm stereo cab .....
To do what you are explaining, using a two jack panel w/ switch, you would hook up two speakers (in parallel) per jack, right?

How would you have to wire the cab to run it at either 4 or 16ohms Mono using the same two jack panel w/ switch?

Thanks,
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 8th May 2012 #8 Lives for gear   Joined: Feb 2010 Posts: 5,476 ...or you could wire it as a 16 ohm cab, and parallel a dummy 16 ohm load... but my question is 'why?' (I mean, I used to drag ten cabs with Gauss and JBLs, 3 Marshalls and a rack of Crowns, thought that it was cool, and now i ask myself 'Why did I do that??????') Now I've got a single small 2x12 THD cabinet that smokes anything I had in the past, and it only weighs about 35 pounds. __________________ "I believe that entertainment can aspire to be art, and can become art, but if you set out to make art you're an idiot." Steve Martin Show business: we're all here because we're not all there. Resistance is not futile. It is voltage divided by current.
8th May 2012   #9
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Quote:
 Originally Posted by Bill@WelcomeHome ...or you could wire it as a 16 ohm cab, and parallel a dummy 16 ohm load... but my question is 'why?' (I mean, I used to drag ten cabs with Gauss and JBLs, 3 Marshalls and a rack of Crowns, thought that it was cool, and now i ask myself 'Why did I do that??????') Now I've got a single small 2x12 THD cabinet that smokes anything I had in the past, and it only weighs about 35 pounds.
Because I just got an Ampeg V4 and the OT tap only goes as high as 8 ohms.. Right now my cab is wired for 16ohms (which I assume is series parallel); I want to use this cab with both of my amps.

8th May 2012   #10
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Quote:
 Originally Posted by adam_l79 Because I just got an Ampeg V4 and the OT tap only goes as high as 8 ohms.. Right now my cab is wired for 16ohms (which I assume is series parallel); I want to use this cab with both of my amps.
Ahh... I had one of those when they were new, with a V2 cab (because the Stones did...). I was working clubs then and it was just too loud for the rooms.

8th May 2012   #11
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Quote:
 Originally Posted by Bill@WelcomeHome Ahh... I had one of those when they were new, with a V2 cab (because the Stones did...). I was working clubs then and it was just too loud for the rooms.
Yeah, I've heard they are really loud amps. I bought it broken, brought it to a tech, and it's ready to be picked up. I haven't played it yet, or any V4 for that matter, I bought it on it's reputation for great clean sounds and from what I've heard on youtube demos.. I noticed that the Stones used the 7 knob models (mine is a 6 knob). I wonder if they were using the Distortion model or the Master Volume model.. Is it so loud that it's hard to tame even at the lowest volume settings? You said that the Altair attenuator messed with the amp's tone. Did you ever try the Master Volume footswitch that was made for the V4?

Anyways, back to the 4x12 wiring.. If I install the two jack switch panel, and wire two speakers (per side) in parallel to each jack, will the switch do anything? Would it be like have two 2x12s in the same cab (no matter what position the switch is set).. or would the switch enable it to run in Mono or Stereo?

Also, like I mentioned in my original post, is there a diagram out there that would allow me to wire the speakers to the switch panel so I can choose between running the cab in Mono at either 4 or 16ohms?

Thanks for the help,

8th May 2012   #12
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Quote:
 Originally Posted by adam_l79 Is it so loud that it's hard to tame even at the lowest volume settings? You said that the Altair attenuator messed with the amp's tone. Did you ever try the Master Volume footswitch that was made for the V4? Anyways, back to the 4x12 wiring.. If I install the two jack switch panel, and wire two speakers (per side) in parallel to each jack, will the switch do anything? Would it be like have two 2x12s in the same cab (no matter what position the switch is set).. or would the switch enable it to run in Mono or Stereo? Also, like I mentioned in my original post, is there a diagram out there that would allow me to wire the speakers to the switch panel so I can choose between running the cab in Mono at either 4 or 16ohms? Thanks for the help, -Adam
I pulled the Altair reference because I realized that I might not have had the Altair until after I got rid of the V4.

The V4 did not sound good to me at low levels, and when I got to a good sound, the level was way too loud. I never saw a master volume pedal.

Two inputs receiving the same sound source would not be 'stereo'.

Brian gave you the possibilities. I don't know what you mean by a switch panel, but yeah you could put in a switch to give you various speaker wiring options.

9th May 2012   #13
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Quote:
 Originally Posted by Bill@WelcomeHome I pulled the Altair reference because I realized that I might not have had the Altair until after I got rid of the V4. The V4 did not sound good to me at low levels, and when I got to a good sound, the level was way too loud. I never saw a master volume pedal. Two inputs receiving the same sound source would not be 'stereo'. Brian gave you the possibilities. I don't know what you mean by a switch panel, but yeah you could put in a switch to give you various speaker wiring options.
Here's a link to the back panel w/ a switch: More Info for item S-H801. I'm new to wiring, so I'm looking for a diagram (for a visual) to help me out.

 9th May 2012 #14 Lives for gear   Joined: Apr 2009 Posts: 1,288 OP: run the 8 ohm and 16 ohm cabs both together in the 4 ohm out of your amp
 9th May 2012 #15 Gear addict     Joined: May 2006 Location: Vancouver Island Posts: 385 To wire this as a stereo 8 ohm cab you would wire each pair of speakers in paralell , each paralell pair will be 8 ohms..... To wire it as a mono 16 ohm cab you would wire the each pair in paralell (like above) and wire each paralell pair in series ..... To wire is as a 4 ohm mono cab wire all 4 speakers in paralell .....
10th May 2012   #16
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Quote:
 Originally Posted by johnnyc OP: run the 8 ohm and 16 ohm cabs both together in the 4 ohm out of your amp
You can run two cabs w/ different ohm ratings through the same amp? In addition to my 4x12 cab running at 16ohms, I also have a 2x12 cab running at 8ohms. I never knew that they could be combined..

10th May 2012   #17
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Quote:
 Originally Posted by adam_l79 You can run two cabs w/ different ohm ratings through the same amp? In addition to my 4x12 cab running at 16ohms, I also have a 2x12 cab running at 8ohms. I never knew that they could be combined..
If you run a 16 ohm cab and 8 ohm cab together you will end up with a total load of about 5.3 ohms. So using the 4 ohm tap there will be a slight mismatch, but one that any well built amp should be able to tolerate. To be sure it's ok check with the manufacturer.

I've run a 16 ohm 4x12 and 8 ohm 4x12 together for years in my custom amp with zero problems. All things being equal the 8 ohm cab will be slightly louder than the 16.

 10th May 2012 #18 Lives for gear     Joined: May 2005 Location: Oklahoma City Posts: 1,988 Ignoring the impedance of the cabinets.....it ALL depends on what speakers are in which cabinet. Some speakers are more efficient than others. Bri
10th May 2012   #19
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Quote:
 Originally Posted by Minion To wire this as a stereo 8 ohm cab you would wire each pair of speakers in paralell , each paralell pair will be 8 ohms..... To wire it as a mono 16 ohm cab you would wire the each pair in paralell (like above) and wire each paralell pair in series ..... To wire is as a 4 ohm mono cab wire all 4 speakers in paralell .....
Is there a way to wire the cab to run at either 4 or 16 ohms Mono?

10th May 2012   #20
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Quote:
 Originally Posted by adam_l79 Is there a way to wire the cab to run at either 4 or 16 ohms Mono?
Here ya go

Shows a wiring diagram to configure a cabinet for:
• 8 ohm stereo
• 4 ohm mono
• 16 ohm mono
• 8 ohm mono (but only uses half the speakers)

IMPORTANT if you build this be sure the sleeves of each jack are isolated
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11th May 2012   #21

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Quote:
 Originally Posted by adam_l79 Is there a way to wire the cab to run at either 4 or 16 ohms Mono?
Yes it is possible but wiring it up to a switch so you can just flick it and change from 4 or 16 ohms would be a nightmare to figure out , at least with my dislexic brain ......

you would need to wire it so you went from all 4 speakers in paralell for 4 ohms to series/paralell for 16 ohms .......

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