Whenever a musical artist refers to trying to stay within their "wheelhouse", they're usually referring to a genre or sound that works well with their voice and style. They don't want to alienate or throw off their fans by doing something way out of their norm. To me, it conjures up a different image.
I picture a big house with a giant waterwheel on the side. They use the water as a source of power for various purposes. When I think of it as an analogy regarding music, it refers to a different meaning. Follow my train of thought, if you will...
The wheel itself has many wedges that each represent a different genre or "flavour" of music. An artist can take these different wedges, like wedges of cheese for example, try mixing them together to see if they work well, not unlike pairing wine with cheese. Creating songs, or cheese for that matter, take time and care to craft, at least authentic ones do.
Creating records, an artist uses a variety of flavours so they don't all sound the same. Instead of just having one album, you would want to check out more of their body of work. People have different palettes and identify with different lyrics or flavours...they find something that speaks to them that may not speak the same way to someone else.
When you see descriptions of wine or cheese, they use imagery, emotions or flavours not unlike song lyrics. Coming back to the wheelhouse, the water drives the music and the lyrics pour out of it...hence the waterwheel analogy. I could go on...I guess I just really love music, finely-crafted songs, water...and apparently cheese.
