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I would use plain old carbon resisters until you find the best value. Once that is achieved, I would think a wire wound may be the best, or one of the best.

So if you play first with carbon types, plan to measure them with an ohmmeter before inserting them, so you know for sure what you are hearing. And too, a carbon resistor will have colorations that will go away when you substitute a Vishay or a tant or a Caddock, e.g.
I would not use a wire wound unless it was a non-inductive type and you otherwise like it.
Lewm (System | Threads | Answers | This Thread)

I suggested the carbon for trial because of the cost. A typical 5% wouldn't make that big a difference in the sound when your changing the values at lot more extreme than that. Vishay resistors are to fragile to keep swapping them out, and buying a handful of different values is way to costly IMO.