Sherlock Holmes needs clues

Doing a lot in acoustical engineering the first thing I would do is plot the frequency response in the room. You could do a simple 1/3 octave plot, but this is probably a little crude for what you are looking for--still it would be a start. I would actually use an MLS method, which is a noise burst and the an FFT transform that would give me the plot. The other thing it would do is give me reflections in the room and timing of those as well as the frequency range that they comprised. Then I would look at the waterfall plot and see what the energy time curves were like in this frequency range as opposed to areas outside this range. This would tell me if the problem was room interaction or not. Cases like this I usually expect it to be room interactions--but not knowing the room or equipment it's impossible to say. Even if I did know the room and equipment I would probably first do some theoretical calculations and then proceed with actual measurements.

Rives: What your are describing sounds like trying to measure the impulse response of the room.

1. What would you use as a noise burst source?
2. What would be your detector? I assume you would locate the detector at the listening position. [I can do an FFT in MATLAB, but need to get the time series data input to my computer to do the plots you describe]
3. What characteristic behavior would you be looking for in the waterfall plot? A more rapid decay of energy in this band?
4. What calculations would you make? Anything besides the peaks and nulls of standing waves? I have an irregular shaped room , but do have a program I use for SONAR development that would give me the normal mode structure for a room like this.

Thanks for the input. I would like to give this a go, as long as I have access to the tools I need to make the measurements.

Judith

Elementary, my dear:

It could be your CD player -- piano is an instrument with many complex overtones. Many CD players (even expensive ones with favorable reviews) fail at trying to reproduce natural sounding piano music. violins, cellos, and even brass instruments are difficult for CD to get right. That's why many folks like analogue!