Privia PX-870 lost mid frequencies?

[greengrapegravy]

Hi, I’m having an issue with the sounds on my Privia PX-870. The best I can describe is the piano sounds are thin, like the way your voice sounds when your nose is blocked. I’m not an audiophile by any means, but having done Music Tech A level a few years ago I wonder if the issue is the mid frequencies are quiet/missing? It affects the middle two octaves the most, surrounding middle C. 

 

There is a bit of story to this issue which might be useful so I’ll include it just in case. I’ve had this piano for something like 8 or 9 years. A couple of years in I first noticed the sound felt like it was lacking “oomph”, kind of thin and the dramatic parts of my pieces weren’t hitting the right way. It came and went sporadically, and whether I changed sounds, turned the piano off and back on, turned it off at the wall, all made no difference. I just put up with it until it magically went back to normal by itself and carried on. 

 

Fast forward to about 2022 and the sound gradually stopped going back to normal. I fiddled around with the adapter my headphones were plugged into and found that I could push the adapter in further than it naturally rested and the sound issue seemed to be fixed by that, almost as if some sound had been “leaking” around the adapter. (I’m fairly sure at this point I also tried a new adapter, with the same results.) I blu-tacked it in place and that was that for a bit. I also picked a new favourite piano sound for good measure (modern - felt like it had more oomph that bright which I was using before).

 

Now yesterday, the sound got REALLY bad again all of a sudden, and no amount of fiddling with the adapter will make any difference. It’s buzzy in the higher octaves, super thin in the mid octaves, and doesn’t feel like it has as much dynamic range as before. Having suspected for a while that this was somewhat headphone-related, (and given that the old pair are disintegrating anyway) I bought a new pair almost identical to the pair I’ve used for years. No luck. The new pair is slightly muddier and more bass-heavy than my old ones, but the same buzzy, thin qualities are there. 

 

I wonder if this is an issue with the actual input where the headphone adapter goes? There are two, but neither is better than the other. Otherwise if it’s a software issue, is it fixable? I’ve tried factory reset today which did nothing. 

 

Sorry for a long post! Thanks 

[Brad Saucier]

Is this happening entirely with headphones only?  Are the internal speakers sounding normal?

[Jokeyman123]

I agree with Brad-to get any idea as to what is wrong, need to know if this sound is the same through the speakers. i can tell you from experience, many of these headphone adapters-from the smaller 1/8" to 1/4" stereo adapters give me problems-seem to not make very good stereo contact unless I monkey around with them (see my avatar for my tech support team). But seriously, a balky stereo adapter can do odd things to the sound-you can lose the stereo effect-and will sound like a thinner monophonic piano as it blends both stereo sides to one out of phase mono signal-losing all stereo imaging, or even only transitioning to one side of the piano samples, but still will sound through both left and right headphone earcups which can make the piano sound-awful.  Now if it is in the speakers too-a different problem. There is a separate amplifier board in these I believe if Casio is consistent with their amplifier boards, which can go bad and can be replaced by Casio for at least several Privias. I think they still will have these parts, I've had repair done by them out of the Dover, NJ facility, very good if you need that. As this seems to be a problem getting worse over time, I would suspect a deteriorating component somewhere-usually but not always leaky or dried out capacitors, if it not the headphone adapter. I had the occasion not too long ago-a sustain pedal did not work. since my others did, and this was brand new and supposedly compatible-drove me crazy until i noticed-the end plug was not quite the same shape as my others. This one was ever so slightly shorter in the shaft's dimensions, thus the critical end connector was not contacting inside-it wasn't going in far enough! I trimmed about 1/16" of an inch around the rubber boot where the grounding sleeve was fastened to the rubber

 

Read these posts-might help-or might make it more confusing but several of us have done some brainstoming on issues similar to yours. Apparently these Casios use the same amplifier chip for the speaker outputs and headphones (we thought so anyway) although the amp board is a little more complicated than just a one-chip design. It could be as simple as poor electrical conduction through even one cable, but this would require internal checking and disassembly-which for a an 870-unless you are experienced at keyboard repair and if it is under warranty-i would contact Casio repair.