Difference Impedence Cabinets Question.

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aussiefreebird
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Difference Impedence Cabinets Question.

#1 Post by aussiefreebird » Wed Aug 09, 2017 11:48 pm

I am building 1x12 and 2x12 Simplex cabs for Bass Guitar. Would like to Run both at same time if possible.
The 1x12 will be 8 ohm Cab and the 2x12 will be 16ohms (wired in Series).
The difference in the cab has started me thinking about difference in volume between the cabs.
If I run them both at once in Parallel will the 8ohm 1x12 cab be louder as it will receive more power?
Less resistance = more current.
I could just run the 2x12 at most gigs but having the 1x12 also would be useful to direct sound to the drummer.
If its a bad idea to use both cabs at the same time I will just wire the 2x12 in parallel as a 4ohm Cab.

Grant Bunter
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Re: Difference Impedence Cabinets Question.

#2 Post by Grant Bunter » Thu Aug 10, 2017 3:46 am

With the 2 cabs in parallel the 2 x 12 will be louder, it has twice the radiating surface/speakers. In fact, the 2 x 12 will be 6dB louder.

If you run both cabs in parallel, with one cab at 8 ohms and 1 at 16 ohms, the overall impedance will be 5.33 ohms. Most amps will handle that.

I have to ask this question as a drummer though, can't your drummer hear your bass rig?
Adding another cab to your rig to aim at the drummer simply raises the stage noise level...
Built:
DR 250: x 2 (melded array) with March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

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Bill Fitzmaurice
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Re: Difference Impedence Cabinets Question.

#3 Post by Bill Fitzmaurice » Thu Aug 10, 2017 6:47 am

If you have a 16 ohm 212 and an 8 ohm 112 the 112 will get twice the power that the 212 does. That's a very bad idea. Two 112 stacked, the lower cab aimed at the drummer and the upper cab at you, is a sensible arrangement.

aussiefreebird
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Re: Difference Impedence Cabinets Question.

#4 Post by aussiefreebird » Tue Aug 15, 2017 8:28 am

Bill Fitzmaurice wrote:If you have a 16 ohm 212 and an 8 ohm 112 the 112 will get twice the power that the 212 does. That's a very bad idea. Two 112 stacked, the lower cab aimed at the drummer and the upper cab at you, is a sensible arrangement.
Thanks Bill. That's the advice I needed and will follow. I am a little confused when I see the SLA PRO plans where a 4x6 can be stacked on a 2x6 which would have a similar situation with the ohms of the cabs. I am guessing there is a different reason it works for the SLA pros as its for a different application where the 4x6 could be louder to reach the far audience. Would be great if you you could explain as I wish to build SLA pros as well.

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Bill Fitzmaurice
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Re: Difference Impedence Cabinets Question.

#5 Post by Bill Fitzmaurice » Tue Aug 15, 2017 10:18 am

aussiefreebird wrote: I am a little confused when I see the SLA PRO plans where a 4x6 can be stacked on a 2x6 which would have a similar situation with the ohms of the cabs.
It's not similar. A 2x6 cab has the woofers wired in series, for a 16 ohm load. A 4x6 cab is wired series/parallel, for an 8 ohm load. Paired the total load is 5.3 ohms, with every driver receiving the same power.

aussiefreebird
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Re: Difference Impedence Cabinets Question.

#6 Post by aussiefreebird » Tue Aug 15, 2017 8:56 pm

Bill Fitzmaurice wrote:
aussiefreebird wrote: I am a little confused when I see the SLA PRO plans where a 4x6 can be stacked on a 2x6 which would have a similar situation with the ohms of the cabs.
It's not similar. A 2x6 cab has the woofers wired in series, for a 16 ohm load. A 4x6 cab is wired series/parallel, for an 8 ohm load. Paired the total load is 5.3 ohms, with every driver receiving the same power.
Thanks Bill. I like to understand how things work and now it makes sense after your explanation.
Time to continue speaker building! Plans are excellent by the way.

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BrentEvans
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Re: Difference Impedence Cabinets Question.

#7 Post by BrentEvans » Sat Aug 26, 2017 1:02 pm

Just to insert, there is a way to do this: wire the 212 in parallel. You'd have to have an amp that can comfortably run 2 ohm loads, but it would technically work. Better yet, do 2 212 series and run whatever amp you like, as you'd have an 8 ohm load, and room to double the stack. A stack that size starts to act more like a line source, netting even more benefits.
99% of the time, things that aren't already being done aren't being done because they don't work. The other 1% is split evenly between fools and geniuses.

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