I normally use poster putty to stick contact mics to surfaces. I recently hung a Metal Marshmallow Pro to my front door for about a week using this putty, and it showed no signs of loosening.
In situations where the putty does not stick well to the surface, I will use it in conjunction with double-sided tape. I will put a layer of tape, a layer of putty, another layer of tape, and then the mic. The putty sticks to the tape very well, and helps the tape conform to the surface and the mic.
Does poster putty affect the sound
The short answer is no. I explain it in more detail and with graphs in the following video.
Watch on Youtube
A summary is in Figure 2. Two of the plots represent sound transmitted to the mic through double-sided tape. The other two plots represent sound transmitted through poster putty.
Figure 2: Graph showing sound transmission through double sided tape (orange and green) and poster putty (red and aqua).
Overall, these plots are roughly the same. The various plots all contain notch filters, and these are in different locations in the different plots. However, these are due to the fine placement of the mic, and not due to the putty or tape blocking sound. The other differences in these plots are not statistically significant for the amount of data collected. From this it can be concluded that the putty is transparent to sound and does not impede the transmission of sound into the contact microphone.
