To check if they work, get a 1.5 volt battery and connect it with a wire to the speaker terminals.
You should hear a scratchy sound as the connections made.
Look at the cone, see how far it moves in and out, compair that to other speakers. The more movement the better bass output, generally.
Push the cone down evenly with your fingers, if it 'scratchs' as it moves. Then the coils been overloaded, heated up and now scratching on the magnet poles. That means its buggered.
Listen very carefully as it gets to the end of the stroke, if it scratches there, its been played loud and the coils hit then end pole plate and its damaged the end of the tube that the coils on. Probably sounds ok, for a while.
That speaker, the sort with the post in the centre of the cone, if its open, like if there's no fibre washer/ring/support between the centre pole and the 6x9 cone. Then often they let in bits of dust, particually iron fileings and grinding grit, anything that's attracted to the magnet. And it gets in there and scratches between the centre pole and the coil and makes a bad sound. Impossible to get the grit out. Dunno why they even make them like that.?
Also, by using the battery trick, you can get a idea of what the speaker 'sounds' like and how efficient itbis.
Efficiency is very important with speakers. 93db @ 1 metre with 1 watt is very good.
That equals 90db @ 1 metre with 10 watts...
3 db is twice as loud.... ie 93 db is twice as loud as 90 db. 96 db is twice as loud as 93 db....
In watts..... 10 watts is twice as loud as 1 watt. 100 watts is twice as loud as 10 watts.....
So, by buying a more efficent speaker can be like doubling the sound, or multiplying the wattage of the amp by 10.
Generally, the wattage of the amp should be the same as the speakers, maybe a little lower.
When a amps overloaded it 'clips'. At that point its putting DC power into the speaker, not AC as it should.
DC power does not make sound, it heats up the voice coil = blows the speaker up.
By using the battery trick to see what the speaker sounds like, is the scratchy battery sound only the high pitched sound? Or is it a mid range sound? Or is it a wide range of sound?
That gives you a idea of what music will be clearest.
Mounting the speakers important too. If air can get from the rear of the speaker to its frount, its not going to give you much bass, as the speaker must act as a piston, pushing air to make the sound.
Put some music thru the speaker when its being held in your hand, very little sound.
Now put the speaker into something so to block the rear of it off, like a large tin, same diameter of the speaker, let the speaker sit on its open rim, suddenly there's more sound.
That's why the position of a speaker in its enclosure in a car makes a big difference.
I have seen speakers just sitting in the hole on the rear shelf of a car. They didn't know the difference...
Till I sat them in concentric with the hole and sealed the edges with a towel... Uh, WoW! uh Thanks!!!!
If there's any holes in the cone, or outer edge (somethimes) you can fix them with silicone sealant.
Just a few ideas to help you out, but push the cone, if it scratches, its buggered.
CRT TV speakers are actually good speakers. If you ever need a 4 inch speaker to fill a hole, they will do the job well.
They may not look fancy, just find one with 4 or 6 ohms and 15 watt plus. Do the battery test.
Tv manufactures are not going to let their TV's down by buying a rubbish speaker, so they get good ones, cheap.
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