Possible cause of harsh mids?

Once in a while you get that used album that sounds good except for a static like distortion on some more dynamic vocals, horns, guitar.  Just typical for some old albums?  Listening to Corea - The Leprechaun.  It's a very good sounding album, well balanced with great dynamics.  But, that annoying distortion rears its ugly head once in a while.  
Used album? It could be played out on bad equipment. Or you are tracking too light, maybe? 
It was probably played on a turntable that could not track those peaks consequently they got knocked off so to speak and you hear distortion. This is assuming your table is tracking correctly. 
If you like that record get RTF's Romantic Warrior. This will really blow you away. Records like the Leprechaun, Friends and My Spanish Heart were done in the years following RTF when Chick was trying to find a new rhythm. I wish he had veered more towards classical jazz. IMHO these interim records were a bit...cheesy. (I have them all) Polydor and Columbia pressings at the time were not the best.   
The sound you describe as static like can be caused a number of different ways and goes by a number of different names depending on what exactly is going on. Sorry but you just kind of have to experience it a whole hell of a lot on a lot of different records to get the feel for what is what and which is which. Once you do it is very easy to talk about. Problem is most don't have that same experience, don't use the same terminology, and so people wind up talking past each other. 

Sound familiar?

One of the most common ones is sibilance. That is when vocals, for some reason especially female but doesn't matter, and can be some instruments too, but certain sounds get the ssss exaggerated and splattered and sounds like static. A lot of people blame this on dirty or beat up old records but really it can be on brand new perfectly clean ones. So really what we are talking about is a bad pressing. For proof I have several copies all nice and clean all the same shape but one has massive sibilance the other hardly any. It's the pressing.  

Another cause of this static sound is mis-tracking. The stylus never traces the groove the way we think. It mostly bounces back and forth sampling the groove. Go watch Peter Ledermann's terrific video on jitter where he explains this in detail. Fascinating stuff. Anyway, this tends to be worse with high amplitude and certain sounds excite harmonic resonance in the cartridge/arm system and so you can get this same sort of sound from breakup when this happens. If this is what it is you can try and tweak VTF, anti-skate (if it is more one channel than the other) and record mats or clamps. But these are all work-arounds, the real solution to this variety of breakup is a better arm/cartridge.  

This can also simply be caused by a dirty record. Doesn't take much dust to encourage the stylus to bounce around and if you are tracking dirt it is gonna sound like it. Walker Enzyme 4 step cleaning is the best you can do. No one ever regretted cleaning their records, not that I know of. 

But honestly my money is on the first one. Whole lot of records do this, it is just the nature of the beast. Most of the time it is the pressing, and not much if anything can be done but to find another pressing. The best ones are found at better-records.com but even those can still have this same problem. Nobody likes hearing this but it's true. Playing records is a trade-off. You can have awesome great sound- just not all the time.
What millercarbon sez...

Spitty sibilants and scratchy violin sections have been my audio bete noir for decades.
Can spitty sibilants and “static” in high amplitude passages also be an amplification issue?  I upgraded my turntable and think I have the alignment of a nice soundsmith cartridge fairly dialed in using Peter Lederman’s instructions and test record.  SQ is way improved and I’m hearing so much more in the music, but sometimes on some records I also what pkatsuleas describes.  Of course one improvement often tempts another, and now I’m looking askance at my 30 year old B&K preamp and amp.  Trying to talk myself (and wife) into new Brystons.
There's a process for figuring out what is causing what. If it was a gain issue then the problem would be present every single time the volume got loud. That is not at all what was described. So it has nothing to do with gain. 

Likewise, if it had anything to do with the amp then it would be consistent. So the one simple fact that it is occasional tells us it can't be the amp. Then to test if it is what I said it gets a little harder. The way I know for sure is what I said, having heard multiple copies of the same record on the same table so the only thing left to explain it is pressing quality.  

Then having heard it and knowing exactly what it sounds like the next time it happens I know what it is. There's just no doubt any more. But that is because I went through the learning curve. 

sryeager, this is in no way an attempt to talk you out of buying a new amp. I would never ever try and talk anyone out of buying a new Raven amp. Or Decware, for that matter. 

Congratulations on the Soundsmith cart. It will be so sweet with a Raven, you will forget all about the occasional spitty pressing.
Thanks.  I hadn’t thought of that.  I’ll give it a try.  I think I may have kicked it up a notch way back when I got the phono preamp (Musical Surroundings NovaPhonomena) to bring the phono volume up to the level of the tuner and CD player.  The phono was quieter when I was using the preamp’s phono stage.
Does this Corea album exhibit the effect every time when played. How do other albums sound, any harshness?

There’s no mistaking sibilance, It’s a narrow frequency range in the upper mids or highs, the sssss sound. It's sounds different than distortion.
Is the loading on your phonostage set correctly for your cart?

MC has listed the most likely causes if this is a persistent problem.

Static like distortion and sibilance are two entirely different things. If the OP had heard this on other records he would have reported it. If his phono stage were overloading it would also do it on other records. I would tend to believe the OP and that it is a unique problem with this record, which means it is a problem with the record. If it walks like a duck and talks like a duck, it is usually a duck. In millercarbon's world it becomes an ostrich.  
I only have sibilance issues on a small handful of records. Sounds like groove damage.
Yes, sibilance on records is atypical. 
I bought some classical records from a private seller online, all had distortion. It sounded like he played them on an old Victrola.

I’ve gone through this for years, realigning cartridges more times than I can remember. All this to no avail, as it is the pressing as stated. Some older records were played on cheap a$$ players without antiskating, hence it is mostly heard in the left channel as the stylus was digging excessively into that groove wall. It sounds like sssss and often splashes into the left channel. It is annoying as hell, but short of tossing certain records, I just put up with it. I often just buy a replacement record, which often times solves the issue. There are also some poorly pressed brand new records that do this, however the ssssss and splashing is not necessarily in the left channel, just excessive sssss sound.
Classic Records Nora Jones come away with me had this issue on certain songs.
Yes Audioguy85, Back in the 80's commercial pressings were hit and miss but the static and other noise was not associated with peaks in the music. It was random. I had several Columbia discs that actually had little bubbles in the PVC with some of them open to the surface. There was a Warner album with something in the PVC, sounded like sand. I always took them back and got replacements. Sometimes the defect is in the stamper and you get exactly the same noise in every copy you get as the store usually gets a batch of consecutive discs off the same stamper. There was some great music on these labels and like you said, sometimes you just have to live with it....until you get a digital copy of the record:-)
One note on sibilance. Lowrider is right. It is unusual to get sibilance in a recording, it happens but it is rare. Sibilance, in my experience is a product of the system and or room. Sound between 3 and 4 kHz has a lot of energy and can bounce around a room for a relatively long period. Then our ears are more sensitive right at these frequencies, a perfect storm. If anything is prominent at these frequencies you will get sibilance particularly with female voices and violins both capable of broadcasting a lot of energy in this area. The BBC developed the Gundry Dip for this problem and many loudspeaker designers will intentionally cut a few dB out of this region to make their speakers sound smoother. My buddies Watt/Puppies do this. 
Thanks for the replies, gents.  Certainly only on a few albums so far.  Not sibilance per se, but more of a distortion on peaks in the mid band - guitars, keyboards, etc.  Bass and treble not an issue.  For example, another one that does it is an old Stanley Clarke album.  (Funny that it's Corea and Clarke!)  First song starts out with some drumming and bass for maybe 30 seconds and sounds good.  I'm thinking, good score for $4!  Then the guitar starts in and it's instant distortion. Grrrr

Brand new Rega P6 with exact cart.  I think I have it set up pretty well.  Most albums sound very good with no problems.  Other than the normal pops and ticks of course!  A definite upgrade from my old Dual.  I am leaning towards bad pressing or just plain worn out.  I am taking notes and will do a good cleaning asap.  Maybe that will help a bit.
pk, I just had another thought. The Exact cartridge has an extraordinarily high output, 7 mV! It may be overloading your phono stage. Here is the inexpensive way to figure it out and fix the problem. Go to Digi-Key and get a few of these, https://www.digikey.com/en/products/detail/stackpole-electronics-inc/RNF14FTD2R00/1974192
They are very high quality metal film resistors, 2 ohms. They will cut the voltage in 1/2 to 3.5. I would insert them right at the cartridge. Cut the resistor leads short, solder a cartridge clip to one lead solder the other lead to the red tonearm lead then cover the construct with red heat shrink. Do exactly the same to the white wire. The resistors are like 15 cents a piece!  If it does not work just return everything back to stock. If it works and sounds fine you have fixed the problem! If you decide to try this let us know what happens please. Another way to get an idea if this is the problem is take the record somewhere where you can hear it on another system and see if it distorts in exactly the same place. If it does then it is the record, if not then it is your system and the cartridge overloading the phono stage is an excellent candidate for the prize.
I was going to offer the same explanation that @mijostyn did - the extremely high output of the Rega cartridge might be overloading your phono stage.  If you have lower gain settings on your phono pre, you might try that.  Or if you have another cartridge with lower gain, you could install that to do a comparison.  If you don't have another cart, you can pick up something cheap like the Audio Technica AT-VM95C for $39 to give it a try.  And having a cheap, backup cart is never a bad idea in case you accidentally damage the Rega cart.