your ears and a sine wave wav that you can download is all you need,
music is my bag, I have had some experience with creating workable listening and recording spaces.
Spending a bit of time and relatively small amount of money on the listening space will be the biggest bang for the buck upgrade you can do,
consider that a very large % of what reaches your ears is reflected sound.
Seeing as you appear to have the luxury of a dedicated music roomseems a shame not to take advantage as you will not have to compromise a living space to get a great listening space.