4 ohm, 8 ohm. What's the deal? Help please!

[shababy32]

Hello ladies and dudes. I am in dire need of some help. I have found a nice 2×10 4ohm candor sale. Very nice cab. My problem is I wanted to pair it with an Ampeg 115HE cab. It's an 8 ohm. So, can I pair the two? If not, why? Is there anyway to make it work? If so, or if not, could u give me a reason why? In layman's terms please!
Thanks!
Sha

 

[FunkHead]

What amp would you be using?

 

[Bass_Pounder]

Bad idea...…….

#1 - Those cabs combined show a total load of 2.67 ohms to your head. If your amp is a 4 ohm minimum, then read no further.

#2 - A four ohm cab will draw twice the power of your 8 ohm cab. For simplicity, lets say your head puts out 300w. The 4 ohm cab will get 200w, while the 8 ohm cab gets 100w.

 

[thewildest]

I could be wrong, but if the cabs are put in series, wouldn’t this work?

 

[bikeplate]

Not unless your amp can work safely at 2ohm

 

[Downunderwonder]

I could be wrong, but if the cabs are put in series, wouldn’t this work?

It might or it might do weird things that are related to unpredictable combined impedance vs frequency.

 

[mmbongo]

I could be wrong, but if the cabs are put in series, wouldn’t this work?

The loss in volume would negate the addition of the extra cabinet, and there would still be a power mismatch. Plus he would need an external box to handle the wiring. What a pain. Forget about series.

 

[Al Kraft]

If the head/amp you're using can handle a 2 (or 2.67) Ohm load you would be safe doing it...whether it will turn out to be a pleasing pairing is another issue. While you could use a series cable or series box/adapter, my sense is that the resulting high impedance would likely hinder a low to medium power head's ability to get you serious volume with any headroom. Without knowing more about the head/amp, that's all I can add.

 

[lug]

The only way to easily do this is if you happen to be running a preamp/stereo power amp combo.

 

[Raf Seibert]

Series? I see that term used here quite a bit. It does not mean plugging a cable from one cab to another. That’s daisy chaining, and it’s another way to connect in parallel. Connecting two or more cabinets in series requires going to some trouble to make special arrangements. Using ordinary speaker cables, either TRS or Speakon, will not achieve series connections. That means nearly all the common ways of connecting more than one cabinet to an amp will result in parallel connections, and all the problems with lowering impedance as well.

I’ll go one step further. If you don’t understand why I’m saying this, you probably don’t know enough to achieve a series connection. Unfortunately, getting that wrong can fry your amplifier. Folks, these aren’t things we made up to make you life harder - it’s the way this stuff works.

Once more, running a cable to one cab, and then another cable to another cab is not connecting in series. It’s still parallel and it will still fry your amp. Btw, this wasn’t aimed at the OP, I just saw some comments that reminded me that some folks have some misunderstandings.

 

[shababy32]

If this makes makes any difference, I'm using an Ampeg SVT3 Pro. It has 2 outputs. I've always wondered why this is because in the past I have just daisy chained from one cab to another. Have I been wrong for, well a long, long time?

 

[Bodeanly]

I'm using an Ampeg SVT3 Pro.

I believe these are 4 ohms. I could be wrong, but if I’m right, you cannot safely use both cabs.

 

[SadowskySteve]

If this makes makes any difference, I'm using an Ampeg SVT3 Pro. It has 2 outputs. I've always wondered why this is because in the past I have just daisy chained from one cab to another. Have I been wrong for, well a long, long time?

I have an SVT3pro. 4ohms is as low as you can go. If you want to use two cabs then they both have to be rated at 8ohms.

 

[Jaco who?]

If this makes makes any difference, I'm using an Ampeg SVT3 Pro. It has 2 outputs. I've always wondered why this is because in the past I have just daisy chained from one cab to another. Have I been wrong for, well a long, long time?

No, you haven't been wrong, daisy chained or using both amp outputs are both parallel. Either way 8+8 still = 4, and 8+4 still = 2.67Ω.

 

[Coolhandjjl]

Series wiring fully assembled cabs that have crossovers can be a risky venture. Series wiring of raw drivers if they are exactly the same can be okay in certain situations.

 

[Smooth_bass88]

Hello ladies and dudes. I am in dire need of some help. I have found a nice 2×10 4ohm candor sale. Very nice cab. My problem is I wanted to pair it with an Ampeg 115HE cab. It's an 8 ohm. So, can I pair the two? If not, why? Is there anyway to make it work? If so, or if not, could u give me a reason why? In layman's terms please!
Thanks!
Sha

Generally a very bad idea to run speaker cabinets of different impedances off the same amp. Refer to the speaker outputs on the back of your amp to determine the impedance.

 

[BassmanPaul]

Running a 4Ω cabinet in parallel with an 8Ω the 4Ω will take twice the power of the 8Ω. In series it’s the opposite, the 8Ω cab will ‘drop' twice the power of the 4Ω one.

 

[Eric Swaim]

Rule number 1: make sure your head and bass cab match up in ohms and power in order to get maximum efficiency.

Rule number 2: when you question if something will work, refer back to rule number 1

 

[abarson]

Let's start with proper notation to avoid confusion.

Serial = a + b.
Simple sum of a and b. The sum will always be larger than the highest number being added.
Example: 8 ohms in series with 4 ohms.
8 + 4 = 12.

Parallel = a || b.
Inverse sum of a and b. 1/a + 1/b = 1/c. The sum will always be smaller than the either number being added.
Example: 8 ohms in parallel with 4 ohms.
1/8 + 1/4 = 1/R
0.125 + 0.25 = 1/R
0.375 = 1/R
2.67 = R

Do not go below the minimum load that the manufacturer lists for their amplifier.
Do not go above the maximum power rating that the manufacturer lists for their speaker.

Be proud of yourself for being able to do the math, and smarter than the average bear.

 

[Rip Van Dan]

The loss in volume would negate the addition of the extra cabinet, and there would still be a power mismatch. Plus he would need an external box to handle the wiring. What a pain. Forget about series.

Actually, it may not negate the extra cab. I ran into this problem when I bought a GK Backline 250 and when I got it, I found out that it had an 8 ohm minimum and should NEVER be used with a second cab. I had a 4 ohm Sunn Beta 202 (2x12 cab) that I had planned to use with it. Luckily my Sunn cab had both parallel (industry standard) and series connectors (very unusual) on the back of the cab.

My solution was to plug my 4 ohm Sunn cab into the amp and then plug the 8 ohm GK BPX115 cab into the series connection of the Sunn cab. Net result was that I was running a 12 ohm connection and could safely run that through the 8 ohm minimum GK amp. The amp put out 125-watts rms @ 8 ohms. At 12 ohms it was putting out somewhere near 85-watts rms. The addition of that second cab with two 12" speakers in it more than made up for the lower power and sounded far better than that 115 did by itself because it was moving a lot more air with the additional two speakers.

Now that Sunn cab is the only one I've seen that had both parallel and series outs, and yes, he would need to invest in a little series box to make it work. But it might work. Unfortunately he's going the opposite way that I did going from a 210 and adding a 115 to it. So he won't get as much extra air movement out of it. I would be more inclined to add another 210 instead of a 115.