Can you use 4 ohm for an 8 ohm speaker for a home speaker?

Question

I have a pair of home cerwin vega speaker that need to be replaced, I want to know if i can replace them with a 4ohm car speaker intead of a 8 ohm home speaker and what is the difference. Can anyone explain the ohm rules?

Answer 1

The transistors used to power the speakers are ": balanced" to see a " LOAD " on the end of the wire. You ae dealing with impedance, ohms, resistance, amperage, and the dynamic curves of the output of the transistors. All these affect the " sound " quality of what you hear from the speakers. Without getting into nitty gritty details that audio gurus would discuss for hours, the most important thing in the physical hook up, is how will replacing the 8 ohms with 4 ohms affect the transistors? Some amplifier circuits actually state " 4 ohm or 8 ohm output " so you are dealing with a crude amplifier that doesnt care. On higher end equipment, though, putting in 4 ohms means that the transistors see 1/2 the " load " they expect and and are continually " shorted out ", using more current flow than they are designed for, which will cause overheating and shorter life. If the transistors are high quality, with huge heatsinks, and were over-designed in the first place by putting larger amperage values than " needed", then you can get away with it, since the over-powerful, high rated transistors can take the extra " short". If you have a unit with cheap transistors which are exactly rated for the output, with no reserve, and are not heatsunk at all or with tiny heatsinks, then you can rapidly overstress them to failure. An 8 ohm speaker will show that the coil of wire wound in the magnet on the back, is about 8 ohms.
A 4 ohm speaker will show about 4 ohms on an ohmeter setting on a typical meter. Since ohms is " resistance", less ohms means that the electricity travels more easily.
A good example would be a toaster. If you put an ohmmeter on the toaster, you find for example 10 ohms. You plug in the toaster and raw, 110 volts goes through the element, and heats it red hot. If you cut the element 1/2 as long, and plug it in, the element still has raw 110 volts, but now only has 5 ohms, and gets yellow hot to white hot, and will last only a short time before it burns itself up. The power generating station at the other end of the house wiring does not care about the huge amount of power being used, and will happily pump in power until the toaster is toasted. If you cut the wire to 1/4 the length the wire will immediately get white hot and probably blow out in front of you.
If you cut the long element in the toaster to just 1/4 inch length, and plug it in to 110, you will have almost NO resistance to the 110 ( 0 ohms ) and the element will light up like a lightbulb, and burn up with a bang.
Back to the amp. The amp is biased or balanced to see an 8 ohm RESISTANCE on the output of the transistors. Think of just shorting out the wires going to the speakers to zero ohms. People do this all the time accidentally with bare wire going into the clips, and the transistors, trying to put out x amps of power see a dead short and will try to put out infinite amps - they are only rated at X amps, and the over stress causes them to over heat, and burn out.. Putting in 4 ohms " One-Half " shorts out the transistors, causing them to try to maintain the pre-set amperage, by using more current ( amps ) than rated. ( it actually is not as simple as this, but close enough for demonstration purposes ).

hope this gives you a rough idea of what is involved without
getting overly technical..

Answer 2

You would be best advised against doing that. Normally there is a crossover network in line with all drivers including the woofer. If the original woofer was 8 ohms and you put a 4 ohm woofer in place of it, that could spell awfulness in terms of sound. Also, some amplifiers might not be "comfortable" with the combination. However, if you bypass the crossover network and run the woofer directly to the connection, that will create a much more stable situation for the amplifier (but not 100% if the amp can't handle a 4 ohm load at all). Even then, the sound quality may not be as good as the original. You will just have to carefully experiment. Do it carefully.

Answer 3

It depends entirely on the amplifier. High quality amps can tolerate a wide range of impedances. The lower impedances are not a problem for the speaker, but can draw too much current from the amplifier output stages and cause overheating. Unless your amp is rated for 4-ohm speakers, it is not advisable to use them. Impedance matching, which used to be necessary in tube amplifiers with output transformers is no longer necessary for transistor-output amps (the most common kind). The 4-ohm speaker will increase the max power output of the amp, if it can handle the current.

Answer 4

Cerwin Vega Replacement Woofers

Answer 5

you cant. The 8 ohm circuit is designed to supply a specific wattage to 8ohm output. When you connect 4ohm speaker there, it will overload amplifier as well as the speaker and one will burn out.

Answer 6

You can...but you run the risk of blowing it up.

go to radio shack and put a 4 ohm series with it.