>>So, if you figure out how to create a similar graph in Excel, help me out man.
I'm going from memory here (misplaced my Office CD in the move) so you might have to interpret the menu items a bit.
I normally enter the FR data (other people's data, I'm too damn lazy to measure my own room) in columns, where the first column is the frequency and the second column is the measured SPL.
Start in the top left hand cell with actual data (eg. your lowest frequency) and select down to SPL for the highest frequency, ie select the data you want to graph.
Insert => Chart, then pick whatever option gets you a new worksheet instead of embedding the chart in the middle of your data table.
I think a little wizard pops up here. It lets you pick what kind of graph style you want. I vaguely remember picking X/Y but that doesn't seem right for an FR graph -- maybe start with a line graph first. You are given all kinds of options for smoothing the lines etc..., stay with "simple".
Other than legends & grid lines, you should be pretty much done at this point.
[EDIT] As long as I'm here, just wanted to say for the record one more time that a single frequency response graph is *not* sufficient to show more than a fraction of the improvements that you can get from good room treatments.
An EQ can fix response at a single point in the room, but you need room treatments (bass traps) and/or speaker relocation to get decent response across a listening area of more than one seat. You would need to measure response at a number of locations and plot them all (before and after) to show this improvement.
Similarly, many of the improvements from room treatment simply won't show on an FR graph at all. Reductions in echo need a more complex graph (spectral decay ?) to see the change. For changes like getting the right level of diffusion (which can open up the sound of a room in a similar way as going from direct surrounds to QS surrounds) I have no idea *how* to measure the results in a graph.
Regarding appearance, it's worth taking a spin through some of the sample rooms on the Rives Audio site to see what you can do. While I prefer the look of rooms with dramatic and highly visible treatments (as, I suspect, do most guys
) they actually design most of their rooms with hidden treatments right down to embedding large Helmholz resonators in custom-built furniture. It's really worth a visit to see what can be hidden in walls and ceilings.
For practical budgets, this translates into "don't hang ugly stuff on the drywall, use the space between the studs".