I have a very basic pair of 2-way bookshelf speakers (6ohms). The tweeter uses a 1.75mF capacitor as a filter. They sound very flat, lacking in sparkle and brightness. As I cannot believe they sounded this bad out of the box, I surmise the problem must be me, getting old and losing top-end reception. I want to change the capacitors for 2.2mF. Will it make a difference?
I agree with the equaliser. It's hard to say whether changing that capacitor would increase the treble in a shelving manner or give you a bump in the upper midrange.
Next time the TV license person knocks on your door, ask them for a second opinion on your speakers.
Online hearing test using some earbuds maybe, just to get a quick idea of where you’re at?
Different filter caps can definitely change the subjective perception as well, regardless.
Different filter caps can definitely change the subjective perception as well, regardless.
An equaliser isn't a practical option. I have completed the surgery and there is a slight improvement, a little more zing to the high hat and noticeably better channel separation.
Does the original cap have "NP" after the voltage? Does it have one crimped end? In that case it is probably electrolytic and after 20 years or so, probably dried up. Way off value. If it is solid looking plastic and says MKP or some other M**, it is probably film and should last forever.
They will almost certainly have a padding resistor in line with the tweeter, meaning you can place a 0.5 to 1.0 uF cap parallel to it so the extreme HF response curve will tilt upwards. It can't hurt to try with a set of clip leads. Do one with and the other without and listen to a momo recording or pink noise.
Just recently I "repaired" a set of vintage loudspeakers. Took out the old electrolytic capacitors and repaced them with non brand polyester capacitors I had lying around. BIG difference in resolution. Frequency response measured absolutely the same though, so no equailizer could have made the same difference.
If there is an L-pad (or even just a single resistor in series) - just before the tweeter, as profiguy says, you can add a parallel small value cap to bypass the resistor at higher frequencies. The bigger the cap value, the more "lift" you'll get. Here's a 2.2uF cap "lifting" the driver response very slightly from about 2KHz, ramping up at about 8Khz
Here's the same with half the cap value:
Here's the same with half the cap value:
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There's lots of conjecture going on here, so perhaps it would help if you told us the make & model or diy details of your speakers.