How to diagnose the need for room treatment?

FWIW, in my post I referred to 'smooth FR' but I purposefully did not say 'flat FR'. Flat suggests to me hearing all frequencies at the same SPL, and when I have heard sounds in a room that were measurable as flat (especially from speakers which allegedly had a flat FR) the result was too much upper-mid and high frequency energy, where as a 'smooth' albeit tilted FR could be much more realistic for most installations.

Personally I really detest peaky mid-range and upper midrange FR, and it is easy thru measurements to determine whether this is attributibutibe to the speaker or the room (or both) by doing both near field and listen position measurements. Am I wrong, or am I missing the point?

Newbee -- I don't think you are missing the point, you are just making some additional points.

To re-state my basic point, room effects at mid and high frequencies are heard differently by microphones + sound level meters than by the human hearing mechanism. The human hearing mechanism tends to some degree to "latch on" to the leading edges of transient waveforms, and give them greater emphasis than what may follow a few milliseconds later. I think that is pretty well recognized. But a microphone + sound level meter monitoring a continuous frequency sweep, or a series of tones covering the different parts of the spectrum, will not do that -- the late arriving sounds at any given frequency will be taken into account, so to speak, simply based on their amplitude. Therefore, whatever the desired tilt of the fr may be, tuning the room or the system to provide it on the basis of that measurement technique will not give the desired result when listened to by a human.

Regards,
-- Al

How about a dumb question :)

I am going to try Room EQ wizard with a good microphone placed at ear level where I normally sit. Do I aim the microphone at the front of the room (HDTV) or do I aim it at the ceiling?

I will be trying to analyze (and perhaps improve) my 5:1 theater system.

The ceiling.

Hi Ghstaudio, I assume you are using the Radio Shack microphone/Spl meter (although you did say a good microphone so its probably not Radio Shack). But If you are buying a microphone and you need a SPL meter, just buy the Radio Shack unit. It is more than adequate and the freq correction is done by the REW set up. Also many/most use this combination, myself included, and help in setup is freely available.

Point it straight ahead. It mut be on a tripod at where your head is.

When you get your Freq response graph, waterfall and RT60, please post them here for interpertation. That will be interesting.
Bob