iPad Pro m4 speakers

Worse? This is clearly a question of subjective judgement - of which you might be the most appropriate arbiter.

The speakers used in recent models of iPad Pro, of which there are four, generally produce substantially better quality audio than other current models of ipad. That said, some anecdotal reports within these forums suggest that the speakers used in the iPad Pro M4 produce less bass than the earlier M1 and M2 models of iPad Pro.

This is most likely due to the iPad Pro M4, due to the reduced thickness of the chassis, having to use speakers with smaller resonators. Obviously, while larger resonators usually produce better sound, the physical restrictions of the iPad chassis will restrict the physical size of the speakers that can be accommodated.