God alone knows which forum this ought to be in; we'll try it here first. Mods redirect at will.... Recent threads on the subject of setting up subwoofers (and BFDs) have made me wonder just how accurate my faithful £25 SPL meter is when it comes to setting the subwoofer level. There's a much-referenced Excel spreadsheet which includes corrections for a standard SPL meter - reading vs actual value at different frequencies. Obviously subwoofer adjustments - positioning as well as level - are a big subject, and as I haven't yet found a satisfactory position, or dealt with some obnoxious room acoustics issues, or hooked up my BFD, results at this stage are going to be a shade sub-optimal. But as a general point: if one is using a processor-generated pink noise test-tone to set one's speakers to the same level, is a standard SPL meter actually accurate enough to adjust the subwoofer level in this way? Or is it a given that one should actually adjust the subwoofer several dB up or down from what the meter suggests is the right level, because the meter is inaccurate when it comes to bass frequencies? And, if so, what sort of correction factor should one use? (I would assume that the meter would read a level that is lower than the true volume at low frequencies, and hence the subwoofer would tend to be set too high if you trust the reading).