4 Speaker Cabinets - Wired for Stereo/Mono

updated 04/03 - Jens Moller

What to do with 4 Speakers in a single cabinet

or

This would give you a Mono Cabinet, were all the speakers were wired to the same output stage of a Power amplifier. This is how most 4 speaker cabinets are wired up from the factory. If you want to be able split this up into 2 sets of 2 speakers, and run the cabinet as a Stereo cabinet, its not hard to do, however, there are loading effects to keep in mind.

You have the option of creating 2 different loads, these will either be 1/2 the impedance of the single speakers (wired in parallel) or 2 times the impedance of the single speakers (wired in series). You need to make sure that you know what your Power Amplifiers are capable of before you decide which you want to do. If you are uncertain, I highly suggest the second option - (Speakers Wired in Series) - as it will likely not overload your amplifiers.

How to split the the internal speakers

Warning: If you are using individual connectors for each set of speakers (Left and Right), do not mount them onto a common metal plate. Doing so may short out signal paths and cause damage to one or more of your Power Amplifiers. Either mount them in separate locations on the back of the cabinet, or mount them on a Plastic, Masonite (fiber board) or other non-conductive material.

Here is how to do each way. The examples show 1/4 inch Phone Jacks, however you can use any connection system that you prefer. In the case of 1/4 inch Phone Jacks and RCA connectors, the center tip is always connected to the + side and the outside case to Signal Ground (the - side).

Warning: Two different Mono Cable designs (schematics) are presented here. Use the one that is appropriate for how you plan to wire the separate Stereo Combinations. Do not mix up these Cables with the wrong cabinets - you could damage your Power Amplifier.

If you plan on using a number of Stereo Cabinets, I highly reccomend that you wire them all the same way - this will allow you to standardize on any cabling that you use and will prevent someone from accidently hooking any of them up incorrectly.

Assuming that each Driver is the same Impedance each individual channel will be: Two 4 ohm speakers - total load = 2 ohms Two 8 ohm speakers - total load = 4 ohms Two 16 ohm speakers - total load = 8 ohms

WARNING: The Left and Right jacks cannot be mounted on the same metal plate (serious damage to some power amps will occur if you do this). Use a seperate jack plate for each channel, mounted on a non-conductive surface

Cable needed to run this in Mono Mode

This cable will reconnect the above Stereo Speakers to operate in Mono Mode so that you use it with a single amplifier. This will cause it to be wired as the Parallel/Series Example at the top of this Web Page.

• Four 4 ohm speakers - total load = 4 ohms

• Four 8 ohm speakers - total load = 8 ohms

• Four 16 ohm speakers - total load = 16 ohms

Assuming that each Driver is the same Impedance, each individual channel will be: Two 4 ohm speakers - total load = 8 ohms Two 8 ohm speakers - total load = 16 ohms Two 16 ohm speakers - total load = 32 ohms

WARNING: The Left and Right jacks cannot be mounted on the same metal plate (serious damage to some power amps will occur if you do this). Use a seperate jack plate for each channel, mounted on a non-conductive surface

Cable needed to run this in Mono Mode

This cable will reconnect the above Stereo Speakers to operate in Mono Mode so that you use it with a single amplifier. This will cause it to be wired as the Series/Parallel Example at the top of this Web Page.

• Four 4 ohm speakers - total load = 4 ohms

• Four 8 ohm speakers - total load = 8 ohms

• Four 16 ohm speakers - total load = 16 ohms

To Use in Stereo Mode With 2 Cables

If using individual Power amplifiers, use a separate cable for each connection. Make note of how you wire these up and mark a set of cables specifically for this purpose. If you ever have a road crew that will wire this up for you, provide clear instructions for them - drawings are the best.

To Use in Mono Mode With a Special Cable

• Power Amp
• Left
• Right

Doing so will allow you to always connect the cabinets up correctly and avoid any strange phasing problems that you can encounter if plugged in wrong.

Using a Switch to select between Stereo and Mono

There is, of course, another way to select between Stereo and Mono, with a DPDT switch - This avoids having to carry around a spare cable, but keep in mind that some amplifiers (for example tube type, with output transformers) always want to see some sort of load on them, so don't flip the switch around while you have both power amps plugged in and running music thru them. This example is a variation of the 'Speakers Wired in Series' above. When running in 'STEREO' mode, the left and right will have an impedance 2X the individual speaker impedance. When running in 'MONO' mode, the combined speakers will have the same impedance as the individual speaker impedance. In running in 'MONO', you are simply connecting up the left channel set of speakers in parallel with the right channel set of speakers. This will accomplish the same thing that building a specialized cable will. I show a DPDT (Double Pole, Double Throw) Switch - I suggest one that is rated for 15 Amps at 120 VAC.

WARNING: The Left and Right jacks cannot be mounted on the same metal plate (serious damage to some power amps will occur if you do this). Use a seperate jack plate for each channel, mounted on a non-conductive surface

For 1/4 inch (and 1/8 inch) phone jacks, you need to verify which solder tabs go to the + and - connections, 1/4 (and 1/8) inch phone jacks have no standard for which of the solder tabs goes to what. Open cased Jacks are easy to verify - just look at it. In an enclosed Jack, you may need to use a VOM/Digital Multimeter to check which connection goes to what. The + and - relate to how the speakers are connected. The speaker should have a colored dot on it to indicate + or it will be marked with a +.

NOTE: We do not work on Home or Car Audio. We work only with Pro-Audio applications. We cannot help you with Home or Car Audio questions.

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