As others have suggested (stated), compression is not the problem. During the mastering process the speed at which the cutter head moves across the disc can be varied to compensate groove width for loud and soft passages. This is true across the record when properly mastered, unless that process is screwed up. With an LP of unusual side play time, say 25 minutes or so, bass may be compromised but that should be apparent across the entire side.
But the slower speed of the stylus through the inner groove can affect sonics, just as Herman describes. Another potential cause for inner groove distortion is cartridge alignment, at least if you use a pivoted arm. Among the different alignment procedures, one can select for average overall alignment, mid-record optimization, or latter half optimization. But if you have not carefully aligned your cartridge to one of these, all bets are off and you will likely hear greater distortion on the inner groove of an LP.
But the slower speed of the stylus through the inner groove can affect sonics, just as Herman describes. Another potential cause for inner groove distortion is cartridge alignment, at least if you use a pivoted arm. Among the different alignment procedures, one can select for average overall alignment, mid-record optimization, or latter half optimization. But if you have not carefully aligned your cartridge to one of these, all bets are off and you will likely hear greater distortion on the inner groove of an LP.