This topic comes up often in other forums and it is alwasy noted that things such as how and where you make the measurement potentially make a significant difference in the results. With the same output at the speaker or even the nearest listeners, a person measuring dBA, slow response at a back corner of the house or at a booth in a room with poor coverage could get a reading 20dB or more lower than someone measuring dBC, fast response in the middle of the house. The relationship of the peak and average levels and which are being reported can also have a significant bearing on the numbers. So can the frequency content, using dBSPL A-weighted can allow for much higher low frequency levels without affecting the actual measurement although there may be a noticeable difference in the perceived level. And of course the application and intended audience can dramatically affect what is considered acceptable. So comparing to any numbers other may use is most useful when as many of these factors are known as possible.