SparkFun Sound Detector Circuit Analysis
A gain of 100 at 8 kHz is a gain-bandwidth product (GBW) of 800,000. The OP-07 has a typical GBW of 500,000, so a typical part will not be able to make the calculated output amplitude.

This is a common problem when using older or low-power amplifiers in audio-ish  applications.  The solution is to use an "audio opamp" an opamp with the extra gain and bandwidth needed for full-spectrum audio.  The NE5523/34 also is a fairly old part, but designed from the ground up for low noise, high gain audio applications.