Everyone ear canal is different so it's a 5 answer question...The way the canal shaped can cause variation on how bass/mids/treble is perceived.
Don't forget that ear wax, although it is a good thing,...
Earwax, also known by the medical term cerumen, is a gray, orange, red or yellowish waxy substance secreted in the ear canal of humans and other mammals. It protects the skin of the human ear canal, assists in cleaning and lubrication, and also provides protection against bacteria, fungi, insects, and water.
...can cause problems if it builds up in your ear canals. Ear wax buildup varies in the amount, viscosity, and the ability of your body to "let it flow out" naturally. The amount of wax in your ear canals will definitely affect hearing as it effectively changes the shape of your ear canal - and narrows it. If you are serious about critical listening when evaluating speakers, headphones or IEMs, you should always make sure you do not have wax "plugs" present that are reducing the area or blocking your ear canals.
In my case, I have smaller than average canals, and periodically need to flush out what I call a "wax worm." It costs $55 for an ear cleaning by the local doctor, but I normally use Debrox (carbamide peroxide) followed with a warm alcohol/water solution flush using an ear syringe. I usually get several tiny bits of hard wax and a bigger "plug", and my hearing improves immediately.
(Be sure to check with your doctor before self-cleaning and flushing to make sure you have no problems or abnormalities that would make unsafe for you to clean your own ears. I was a hospital corpsman assigned to the EENT (Eye, Ear, Nose and Throat) clinic at the Oakland California Naval Hospital in the mid 1960's, and I am familiar with the configration and condition of my ears.)