Sound, light, heatRebuild shelfHand tools, works as-is

Speaker driver

Also called woofer, cone, 8 ohm, laptop speaker.

A coil, a magnet, and a cone. TVs and stereo speakers are the ones worth mounting. Laptop and phone speakers are fine as alarms and poor as music. Read the impedance before you parallel two of them.

If you are new to this category

Speakers, lamps, heaters, and displays. To test a speaker, touch a 1.5 V cell to the terminals for a moment. The cone should click once. A heater can start a fire if you remove the part that was supposed to shut it off.

Heat and bright light usually mean household voltage. Unplug first. If the original safety part is open, find out why before you replace it.

The one-second speaker test

Touch a 1.5 volt cell to the two terminals for a moment only. A good cone clicks and moves. A scrape means the coil is rubbing, which will sound bad even if it still makes noise. The ohms printed on the magnet, often 4, 6, or 8, tell you what amplifier it expects.

Strong neodymium magnets. Hard-drive magnets slam together hard enough to blood-blister skin and shatter into sharp chips. They also wipe media and bother pacemakers.

Specification. The right-hand column is what is typical. The label on the part in your hand wins if they disagree.
What to look for	Usual figure
Impedance	Usually 4, 6, or 8 Ω, stamped on the magnet. Two 4 Ω drivers in parallel is 2 Ω, which many amps will not do.
Power	A laptop speaker is about 1–2 W. A TV speaker may be 5–10 W. The stamp is optimistic marketing as often as it is a rating.
Enclosure	A bare driver needs a box or it will sound like a telephone. Keep the original box if you liked the sound.

Volts are electrical pressure, amps are how much current is flowing, and ohms are how hard the part resists that flow. A higher voltage than the part was built for is how salvage parts die on the bench. If a cell in the table says “read the stamp”, that stamp is the whole specification.

What people actually use it for

An amplifier you already have
An alarm
The donor enclosure as a finished speaker

Leave this one when

The cone is torn, the voice coil rubs, or the surround is foam dust. Re-foaming is a hobby, not a side effect of salvage.

Buying a new one is the better idea when

A driver with a frequency-response curve, once you are building a speaker rather than reusing one.

How to tell if this one still works

1.5 V cell, momentary. One click, cone moves freely, no scrape.

Step-by-step on the bench: Test a speaker or voice coil

Tools you will want: AA cell, Meter.

Words on this page

Short meanings, so the rest of the entry is readable if you are not already doing this every weekend.

parallel: Connected side by side. Cells in parallel share the current and stay at the same voltage. Only match cells that are in similar condition.

Where people actually find it

11 notes, most useful first. “Leave it” means the part is in that machine and you should not take it: it is dangerous, worn out, or only useful if you already know that exact repair.

Harvest at a glance
From	Call	How many	How often	Where it sits
Clock radio or stereo	Prize	2	always	Left and right.
Powered or Bluetooth speaker	Prize	1–2	always	Each cabinet.
Headphones	Prize	2	always	The earcups.
Laptop	Worth it	2	usually	Front edge, left and right.
LCD television	Worth it	2	usually	Left and right inside the rear cover.
Mobile phone	Worth it	1–2	usually	Bottom speaker and earpiece.
End-of-life car	Worth it	2–8	usually	Doors and deck.
Alarm clock	Worth it	1	usually	The back.
LCD monitor	Bonus	2	sometimes	Bottom corners, on models that had them.
Motorized toy	Bonus	1	usually	Inside.
CRT television or monitor	Leave it	1–2	usually	Inside.

Prize — take this firstClock radio or stereo2 · always
In this particular machine
Real cones, impedance stamped.
Where to look
Left and right.
How to get it out
Unbolt. Keep the enclosure.
The condition to expect
Foam surrounds may be dust.
Prize — take this firstPowered or Bluetooth speaker1–2 · always
In this particular machine
Stamped impedance.
Where to look
Each cabinet.
How to get it out
Unbolt.
The condition to expect
Surrounds may be rotten on older ones.
Prize — take this firstHeadphones2 · always
In this particular machine
Often 32 Ω, low power. The stamp is on the driver.
Where to look
The earcups.
How to get it out
Desolder the cable.
The condition to expect
Good if the cone is not crushed.
Worth pullingLaptop2 · usually
In this particular machine
Small, often 8 Ω, 1–2 W, with a plug.
Where to look
Front edge, left and right.
How to get it out
Unplug. Note which side.
The condition to expect
Cones are usually intact.
Worth pullingLCD television2 · usually
In this particular machine
Often 8 Ω, several watts, with a plug.
Where to look
Left and right inside the rear cover.
How to get it out
Unbolt. Note impedance.
The condition to expect
Cones usually intact.
Worth pullingMobile phone1–2 · usually
In this particular machine
8 Ω class, under a watt.
Where to look
Bottom speaker and earpiece.
How to get it out
The grille is glued.
The condition to expect
Distorted if it was drowned.
Worth pullingEnd-of-life car2–8 · usually
In this particular machine
4 Ω is typical. The stamp is on the magnet.
Where to look
Doors and deck.
How to get it out
The screws are usually Torx.
The condition to expect
Cones get wet and rot.
Worth pullingAlarm clock1 · usually
In this particular machine
Small, for the buzzer.
Where to look
The back.
How to get it out
Fine.
The condition to expect
Good.
Bonus, if you are already in thereLCD monitor2 · sometimes
In this particular machine
Small, 4–8 Ω.
Where to look
Bottom corners, on models that had them.
How to get it out
Unplug.
The condition to expect
Fine.
Bonus, if you are already in thereMotorized toy1 · usually
In this particular machine
A small mylar cone.
Where to look
Inside.
How to get it out
Fine for noises.
The condition to expect
Good.
Leave it — present, not yours to reuseCRT television or monitor1–2 · usually
In this particular machine
Ordinary speakers, and not worth the tube.
Where to look
Inside.
How to get it out
Leave them.
The condition to expect
Fine, and still not worth it.