iphone 16 pro max speaker sound low

Expecting spatial audio from the builtin speakers on iPhone is an unrealistic expectation. They're not full fidelity for sure, but for cell phone speakers, they're about as good as you're going to get in a cell phone. If you want the best sound, including Spatial Audio, you need to listen through earphones. And for Spatial Audio specifically, see this --> Listen with Personalized Spatial Audio for AirPods and Beats - Apple Support

gowtham14 wrote:

speaker support dolby sounds. I can’t feel iPhone original speaker sound like loud punch bass. All are said iPhone 16 pro max speaker sound quality very good compare with other iPhones. But my iPhone speaker low sound quality. Call quality super but when I listen music or videos ( my iPhone 16 pro max uk dual physical sim slot )

I'm guessing you don't under the physics of how speakers move air to produce sound? You simply cannot expect full volume, high fidelity sound from the little speakers in a cell phone. They simply can't move enough air to produce realistic sonic soundstages. The Sim has nothing to do with this. If you want realistic full fidelity, you need headphones. No one can change this for you and honestly, your expectation is unrealistic.