Clipping on Radio Shack SPL Meter RCA Output

[Retread]

I have the TrueRTA spectrum analyzer software. It has an oscilloscope mode by which you can see the actual waveform of the signal being fed into the computer.

I fed the RCA output from the analog Radio Shack SPL meter into the laptop that hosts TrueRTA with the intent of measuring 3rd harmonic distortion and found that the SPL meter output clips at zero on all scales. So, while the display meter itself is bouncing around, but the output waveform is clipped. By the point at which the meter is pegging, the output is virtually a square wave.

I've just ordered a calibrated microphone and preamp to take care of this problem.

[Lwang]

I haven't noticed clipping until I am well past the scale of the meter (in the case of the digital meter, it is +10dB).

Although I've noticed that the SPL meter does not capture the true peak, even when it is in min/max memory or peak hold mode, since I could see on the scope a much higher peak reading, albeit with a impulse signal of a somewhat high freq.