Vinyl and subwoofers


I have a pair of Thiel 3.6 and a Thiel ss1 sub with the prescribed Thiel crossover. I have a pretty good vinyl rig with a Clearaudio performance se, Stradivari cartridge and a ARC PH8 phonostage. Although the Thiels go down to 20hz, an audiogon member  persuaded me that I was missing something without a subwoofer. What I have heard with the Thiel SS1 sub and prescribed crossover is an amplification of record imperfections I was not aware of without the sub. As well, the overall sound seems often muddied. Has anyone else had this problem with vinyl? Is this a problem with my setup? Any insights are very appreciated.
golferboy
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A second thumbs up to the kab rumble filter.  If your cartridge  is picking up low-frequency feedback it will double in the subwoofer and make things really muddy
Thanks tons for all the responses. I have room treatments, a power re-generator supplying clean, constant 120. A Thiel PX02, a passive integrator tailored to the 3.6. My CJ pre inverts the phase, so I switched the red and black at the speaker terminals. I'll try to be more articulate in describing the problem. A scratch on a record or the end of a record will turn into a thump, which is then magnified by the sub. This is not the problem. However, on those records that are poorly pressed, there is sometimes a gravely sound and on some occasions, this gravely sound has a bass component that is amplified by the sub, turning what should be tight bass into extremely bloomy and unmusical bass, which then muddies the music. Back in the day, 35 years ago...when I thought that putting a penny on a headshell might help get more music out of the grooves...I might have damaged more than a few records. If the sub was not there, the gravely sound would still be there, but easily overlooked without the sub. I'm going to recheck my turntable cartridge setup and look into a rumble filter, something I didn't know existed. Thanks in advance for future responses.
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Just read about the KAB rumble filter. I had no idea this problem of pumping woofers was so common. I am still shaking my head. Why didn't the experts who designed the audiophile skyscraper put in a button for the rumble-filter floor in all of the elevators serving the analogue section of the building.