Most car speakers are 4ohm and most guitar amps are 8 ohm.
A 4ohm speaker will be damaged quickly hooked up to a 8ohm amp, but you can wire 2 4ohm speakers in series(+ of speaker 1 to amp +, - of speaker 1 to + of speaker 2, - of speaker 2 to amp -) to work with a 8ohm amp.
Car speakers will not last long though with a guitar amp because they aren't made for that kind of use.
if the 4 ohm speaker is of sufficient wattage then it wont suffer any damage. what CAN happen is that a 4 ohm load on the output of an amp can overload the output transistors and burn them out. basically less resistance more current flows , exceeds transistor capacity. dead amp. the only time you will blow speakers is if you are trying to put 100w through a 10 w speaker. then it gonna die!
yes. amps are usually designed with an output load in mind. that can usually be 4 ohms to 16 ohms. a speaker is a dynamic load. what it is is a coil of wire suspended by a cone in a circular groove in a permanent magnet. what power the speaker can handle depends on how strong the magnet is. the gauge and number of winds in the coil and the stiffness of the suspension. the part of the speaker that connects to the rim and allows movement.
assume you have a 5W amp module. the most obvious thing to do is to try to match it to a 5W speaker.If you only have a 10W speaker then you are not going to hurt the speaker or the amp you just wont get full efficiency out of the amp.
Now lets use that 5W amp to drive a 50W speaker. we are now putting only 1/10th of the power that the speaker can handle. you will hear sound but there wont be any punch to the sound. the movement of the speaker cone is called excursion , how far back and forward the speaker cone can move. with only 1/10th of the power the cone wont move much at all.
go to the other extreme and put a 1/2 W speaker on a 5 W amp, you are now putting 10 times the power into the speaker than it was designed to handle. the speaker cone will try to move beyond the limits that it was designed to and the suspension will fail. blow out the speaker. unless the added current and voltage through the coil doesnt burn it out first.
now that was all assuming the amp and speakers were the same that is 8 ohm load and 8 ohm output amp.
with load mismatch the amp controls the voltage the only thing that can change is the amount of current . To horribly oversimplify this if you have half the load you get twice the current. by ohms law twice the current is twice the power developed assuming the voltage stays the same. so now your 4 ohm speaker is trying to pull 10 W out of you amp.
Valve outputs are slightly different because they have a transformer as the load and the speaker is on the secondary.
That is very helpful! Thank you!
I know! Right!
Damage can also occur to the speaker coil from ohm mismatch. One of the parts will be damaged for sure.
But the real damage to speaker coils comes from using a instrument that has a high level output in a small dedicated range of sound that's used with a speaker that's designed for a lower intensity wide range of sound for stereo audio output.
You can use car stereo speakers, but it will damage them a little at a time and eventually rag them out and make them sound terrible. If you use a guitar speaker, that will not occur.
Could be true But I have some I built 7-8 years ago that are still working well I do agree a guitar speaker is build for that purpose But I dont seem to have any problems with car or boat speakers And lots cheaper
Guitar speakers can be expensive, but there's plenty of speakers now that can be purchased for as little as 15 bucks. Mostly 6" and 8", but some 10" speakers can be had for less than 40 bucks that sound ten times better than a little car stereo speaker.
Jensen MOD speakers, Celestion has some 8" and 10" from 30 to 40 bucks, Eminence and WGS have 2 or more that I know of under 40 bucks.
Good and correct speakers are available for affordable prices these days and they sound so much better. The cost of parts are coming down.
I used a Home Theater Subwoofer in my little 4watt bass amp. Lasted 6 months. Bass speakers are so much more expensive, but Eminence now has a 8" and 10" available for 75 bucks. They used to be in the 200 dollar or more range.
I and others use tons of Ford car speakers 6x9 full range they are cheap on EBay and work great
I have gotten away from everything but guitafuel boards Over the years iv built most of them out there But for simple and reliable its GF for me They take quite a beating can overheat and still come back Iv hooked up every speaker combo to them and never had any problems I have a two speaker 3 watt and a four speaker 5 watt that I use for my own Both have Ford 6x9 speakers Iv never overloaded one of his boards He was the original Artec seller Then when other people started to sell them he went on his own and had the GF boards made I think to a better standard Just my opinion