Speaker Cab Impedance Question

[Stike]

So I have 2 Port City 2 X 12's, they both have 16 ohm speakers. Would I be better off wiring them in parallel so the cabs are 8 ohms or in series so each cab is 16 ohms? I've never really messed around with this much before and was wondering if one rating could possibly sound better than the other?

Also seeing as sometimes I use just one cab (lazy) and other times I use both how tricky would it be to add a through jack to one cab so I could run them essentially as a 4 X 12?

[geoff_hartwell]

I always try to make sure to match the impedence of the amp and the speaker cab, but in a pinch I've used a PowerBlock into a Carvin floor monitor (8 into 16) and nothing exploded. If I were in your shoes I'd think about what ohm rating your amplifier is putting out, and if you have flexibility in that (multiple outputs etc). For example, my new favorite amp puts out only 8 ohms because of its transformer, not 8 or 16 so my choices are somewhat limited, but there are always several ways to make something work. I also never bring more than one cab because I don't want to move more than one, ha! There are definitely easily accessible diagrams for several different jacks, including the cool Marshall one that can be mono or stereo.

What ever you decide please keep us posted, and all the best of luck.

[dogsrock]

I could be wrong but I think 16 ohm speakers in series is 32 ohms.Two speakers parallel is half,two speakers series is doubled

[murkat]

I have always wired a cab to match the ohm load of the speaker (s)

Back in the day, Andy Marshall insisted this method to me for the sake

of the speakers, like a marshall 4x12 cab, 4 16 ohm speakers~ a total of 16 ohm load.

and you can safely run the cab with a 8 ohm load head (mesa).

But, it boils down to personal taste.

[Bobby Marshall]

I did read somewhere that Steve Morse had his cabs rewired from 16 ohm to 4 ohm as he preferred the sound/feel/interaction with them wired that way, but that is HIS preference. For mere mortals, matching the cab to the head is what you want. And use speaker cable to connect them. I never even knew what speaker cable was until AFTER I bought a tube head many years ago. Luckily I did not learn the hard way on that one.

And you also want the speakers to be able to handle the load. If you have four 20w speakers connected to a 100w dimed amp, have the fire extinguisher ready.

[stobro]

Is each cabinet rated at 16 ohms, or each driver within that cabinet? If each driver is 16 ohms, then the cabinets would have to be either 32 ohms (2x16 ohms series connected) or 8 ohms (2x16 ohms parallel connected). You can't get 16 ohms total impedance from a pair of 16 ohm drivers.

Almost all cabs and heads that have two jacks are wired with the jacks in parallel, so running both cabs at the same time will present the amp with either a 16 ohm load (2x32 ohms parallel connected) or a 4 ohm total load (2x8 ohms parallel connected).

If the amp has an output transformer, the load should match the rating of the amp. If it is overbuilt well enough, you can get by with a load as low as 1/2 the amp rating. If the amp is solid state and has no output transformer, then the load can be any impedance as long as it is equal to or higher than the rating of the amp. Output power will decrease with higher impedance loads. Solid state amps should never be connected to a load that has lower impedance than the amp's rating.

[veatch]

stobro is correct. What output impedence(s) is your amp? You can wire both cabs to be in parallel for 8 ohms each (assuming 16 ohm speakers). If you do not have a 4 ohm option and you do have a parallel jack in one of the cabs, you can replace the jack with a switch jack and wire it for series. That would give you two 8 ohm cabs by themselves or 16 ohms if both are connected.

[Stike]

So have ya'll ever seen the Far Side cartoon with the kid pushing on the door that says Pull trying to go inside the "school for the gifted"? I just went back and looked at the wiring diagrams on the Eminence site and sure enough I read it wrong. Parallel for 8 ohm cabs it is. Duh.

[veatch]

[Never2Late]

Newbie here - I just bought two empty 4x12 slant cabs, and a boatload of speakers. Considering that each speaker is simply an Ohm-load to the amp, I'm assuming the speakers can be wired series/parallel in such a manner that one could 'mix' 8-Ohm and 16 Ohm speakers in the same cab, but wire them in such a manner that the total load connected to the Amp is 8, or 16 ohms depending on the wiring. Is this correct, or is there only 'one' way to wire a 4x12 cab, and all speakers must be the same impedance?

[HSB0531]

If each speaker is 16 ohms and you have 2 cabs of 2 each:

Best to wire each 2x12 in parallel.

This will give you an 8 ohm cab.

When you plug them both into your amp you'll see 4 ohms.

[Bobby Marshall]

I always thought a 4x12 with 16 ohm speakers could only be wired 16 ohm or 4 ohm as i mentioned above regarding Steve. Morse. Most do 16 ohm as two 16 ohm cabs make your amp see 8 ohms. Two 4 ohm cabs would make the amp see 2 ohms. I have stereo power amps so i just plug one cab into each side but ymmv.

I would find wiring diagrams on scum back speakers website.