Matching Speaker drivers

I ran into a problem with my PC speaker cabinet project, After completing the mock up of the second speaker cabinet, I noticed the right speaker was less loud than the left one. Changing the wires and the output terminals did not change anything. I measured about 7 db difference between them using pink noise.

Apparently all speakers have some degree of mismatch.

Anyone had any experience with this? How do you compensate for this? I am thinking of an internal L pad on another set of 4 inch speakers this time that sound not so different from each other,
 

eriksquires

Member
2013-05-10 4:11 pm
Basic,

Are these full range? That is, are you using a single driver, or is this a multi-way with a crossover?

Assuming it's just one driver then you could probably buy a third one and get at least one matching pair. :)

If this is a multiway then things get more complicated.

Best,

Erik
 
I ran into a problem with my PC speaker cabinet project, After completing the mock up of the second speaker cabinet, I noticed the right speaker was less loud than the left one. Changing the wires and the output terminals did not change anything. I measured about 7 db difference between them using pink noise.

Apparently all speakers have some degree of mismatch.

Anyone had any experience with this? How do you compensate for this? I am thinking of an internal L pad on another set of 4 inch speakers this time that sound not so different from each other,

I think you should measure the DC resistance next. Sounds like a fault. Should be 3 or 6 ohms for 4 or 8 ohm nominal. No easy way to test the magnets, so we'll have to wait and see.
 
Another twist in the tale of Hi Fi audio.

I read somewhere about matching tweeters and also that quality control is important, as important as the speaker design itself. I never put two and two together and realized that the left and right speakers consist of two separate components, and if QC is not done correctly, or it is not possible to do, then they will sound different.

I tested another set of powered PC speakers I had, the Creative ones bought last year, and was surprised to hear a distinct difference in tone between left and right speakers with pink noise. The 'note' played by the pink noise on each speaker was different. This could be due to the fact that they are different inside, one speaker is empty and the other one has the transformer and electronics.

Yes the speakers I mentioned are full range and come from a PC speaker. I tested another PC speaker driver pair and they sound different, but within a few DB with pink noise.

I have learned my lesson : test the pair before building anything. My work on the cabinet is now wasted.

One other question, I had another full range fail on me while testing the speaker using a 9 volt and then 2 AA batteries connected to the AC terminals of the PC speaker amplifier. Is it possible running it with low voltage caused distortion that burned out the speaker or could it be just that it was an old speaker? It got terribly distorted and then went out. infinite resistance across terminals.

How long can I expect a speaker to last anyway? My car speakers burned out after about 11 years or so.
 

Jay

Banned
2003-02-11 9:02 am
Jakarta
One other question, I had another full range fail on me while testing the speaker using a 9 volt and then 2 AA batteries connected to the AC terminals of the PC speaker amplifier. Is it possible running it with low voltage caused distortion that burned out the speaker or could it be just that it was an old speaker?

Amplifiers may produce very high SPL (that may kill speaker, usually tweeter) at very high frequency. This is caused by oscillation. Oscillation can be caused by clipping. Clipping can be caused by too low supply voltage.

(With certain circuit, too low supply voltage can cause DC at output)

How long can I expect a speaker to last anyway? My car speakers burned out after about 11 years or so.

Forever if not abused like in your case :D
 
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Amplifiers may produce very high SPL (that may kill speaker, usually tweeter) at very high frequency. This is caused by oscillation. Oscillation can be caused by clipping. Clipping can be caused by too low supply voltage.

Yes of course. But devices designed to be battery operated - and we have all run transistor radios or portable stereos until the batteries lost all power, must have some protection circuitry? I will just have to run the remaining speaker of the pair at similar under voltage, that is 2 volts to 9 volts DC.. If it burns out I have a crisis and opportunity to try my hand at speaker repair and rebuilding.
 

Jay

Banned
2003-02-11 9:02 am
Jakarta

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Jay

Banned
2003-02-11 9:02 am
Jakarta
Sure. But is it really possible to zero in on a amp chip based on the circuit?

You showed a PCB with a known size of chip under small heatsink, from a typical PC speaker...

I have opened more than a hundred of PC speakers, so I have Statistics here...

Of that 14-pin (or 16-pin) in less than 2W category I have only seen 2 types. Of course, 2025 (from various manufacturers) is the most popular because it is IMO the best sounding. Others use a 8-pin IC (like opamp), the also popular LM386, which sound is worse but the current requirement is low so can use the USB port for power supply...