More of my $.02. I had a Icom 7600 for 6 years, and bought a 7300 as a backup, as I didn't want a radio to crap out during a contest and leave me hanging. After a year of alternating the two in many contests, IMO the 7300 was simply the better radio all around, so I sold the 7600 and bought another 7300. The 7600 only had Audio Peak Filter and Dual Receive over the 7300, which I very seldom used anyway (some will disagree with me).
The RX audio in the 7300 sounded better to my ears. But I maintain, It *ALL* depends on the speaker...I don't care what radio you have. Ham radio transceivers are not audiophile-quality products. The internal speakers are top-firing and tiny, a compromise at best. For aesthetics, I bought a pristine used matching SP-38 (I won't pay ridiculous retail prices for matching speakers), which is 4", front-firing, and a deep cabinet. Due to its size, it emphasizes the high frequencies, and provides crisp communications-type audio, easier to distinguish voices, but also a little harsh, which might be considered fatiguing to some. I have an old DCM audio system speaker hanging around, which uses 8" and 3" drivers. I put a switch between the two, and compared. What a difference! The noise/hiss was virtually gone, voices were warmer and more mellow...easier to listen to when ragchewing. But there's reasons to use both, depending on band conditions and operating preferences. When contesting, I always use mic/boom headphones.
Then again, a crappy muffled, distorted transmitted signal will sound crappy on whatever speaker you use

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Bob K7JQ