Add resistor to increase cab resistance?

[BluesMagoo]

Hi,
New to the forum and I've been searching many many threads for the following question.

I have a 1x15" cab. rated at 4 ohms. I just purchased an additional 8 ohm cab. (2 x 12 plus tweeter)

How can I increase the 4 ohm cab. to 8 ohm restance?

My understanding is that it is possible to add a resistor in the 4 ohm cab. to increase the resistance to 8 ohms.

I would like to do this so that when I hook up both cabs, I'm creating a 4 ohm resistance load to my amp and that both speakers should have a balanced sound. ie., both provide equal volumes.

Can anyone advise me or point me to a thread with some discussion on this subject.

This is a very informative site and thanks to anyone who can help.

Dave

[john m]

Not a good idea. The ohm rating on a speaker is the impedance not the resistance. They are not the same thing.

If you wanted to reduce power to the speaker by limiting the current to the speaker, it would take a very big resistor-
100 watts, 200 watts or larger. Then you'd have to do something to get rid of the heat created by the resistor--
all of the energy would be turned into heat instead of sound.

[BurningSkies]

Originally Posted by BluesMagoo

Hi,
New to the forum and I've been searching many many threads for the following question.

I have a 1x15" cab. rated at 4 ohms. I just purchased an additional 8 ohm cab. (2 x 12 plus tweeter)

How can I increase the 4 ohm cab. to 8 ohm restance?

My understanding is that it is possible to add a resistor in the 4 ohm cab. to increase the resistance to 8 ohms.

I would like to do this so that when I hook up both cabs, I'm creating a 4 ohm resistance load to my amp and that both speakers should have a balanced sound. ie., both provide equal volumes.

Can anyone advise me or point me to a thread with some discussion on this subject.

This is a very informative site and thanks to anyone who can help.

Dave

Dave, there's no free ride.

You can put in a resistor, or resistor array to do what you want, but that array will see a lot of the wattage going to the cab and also generate a lot of heat.

You won't get a balanced sound because half of what you're sending to the cab will end up heating your resistor, rather than going to the speaker. You're much better off trading out the cab you have now or finding an 8 ohm speaker that fits the cab's specs.

[Codger]

Originally Posted by BluesMagoo

Hi,
New to the forum and I've been searching many many threads for the following question.

I have a 1x15" cab. rated at 4 ohms. I just purchased an additional 8 ohm cab. (2 x 12 plus tweeter)

How can I increase the 4 ohm cab. to 8 ohm restance?

You need a transformer not a resistor. Weber sells them. (WZC-50 and WZC-100 Impedance Converter). Power limited, 100W max. Never tried one myself.

[Roadkill]

Usually the best thing to do is sell your cab and buy an 8 ohm one. It might be almost worthwhile to see if you can order an 8 ohm driver from the cab manufacturer if that cab was ever offered as an 8 ohm model. Just swapping in a random 8 ohm driver may or (more likely) may not sound good.

[bongomania]

Adding a resistor is a very bad idea in this case.

[Stanley Pugh]

Years ago I used a variable resister on a speaker. It worked for a while.
Then it made a loud bang and that was that.

[Jazzdogg]

When I found myself in that situation several years ago, I bought a 2-Ohm-capable head. Problem solved. Perhaps not ideally, but solved nonetheless.

To the OP: are you in love with your current amp?

[BluesMagoo]

Originally Posted by Jazzdogg

When I found myself in that situation several years ago, I bought a 2-Ohm-capable head. Problem solved. Perhaps not ideally, but solved nonetheless.

To the OP: are you in love with your current amp?

Thanks everyone for your feedback.
With your advice and recommendations, I've decided to either look for a different head with a 2 ohm capability or trade the cab in to defray the costs on a new head to drive my new Messa 2x12 + tweet cab.

I'm going to research options on heads and try to figure out what head would please me . . . . . old school (warm + punchy)

Thanks a bunch folks, this really helps.
Dave

[trevcda]

Ah, whatever happened to excess of bass playing? Buy another four ohm cabinet and run the two in series. Blammo! Eight ohms! Soooper cool stack! More output!