All modern receivers...what are you talking about? What "receivers" that are in common use by many or most of us can tell is the frequency curve of our system?
If you want lame advice DON'T do this!
Have you ever seen a member ask for advice about their system and don't understand why they need to make a change? Mistakes in this hobby are generally expensive. Does a list of components tell you how they sound together as a system? No Does a picture of a room tell you how the system sounds in the room? No. Think about the dollars that have been flushed away because the problem was the room and no matter what you stick in there or how much it cost it won't git er done. A flat in room frequency response is a starting point before changing anything. So, why don't more people post measurements when asking for advice? If you want lame advice DON'T post your system in your profile. If you want good advice post your system and a pic. If you want excellent advice include your in room FR measurements (which almost all modern receivers provide or REW can do for free).