Spectrogram: Format and Edit

I have a

Neighbor From Hell

in the upstairs apartment and have recorded her booming footfalls. I need to produce 4 graphs for the lawyer-mediator, comparing bare feet with different footwear. I was able to make 2 nice ones on Audacity 2.1.2 a couple of months ago but am having trouble getting formats of the new ones to match. The x-axes of the new ones go from 3.00 Hz to 20,000.00 Hz instead of 3 to 3500 Hz and needlessly clutter up the graph with .00. The Y-axes go to -145 db instead of -90 db. I have in vain searched the manual and wiki for ways to edit and format the plots, but may well have missed something. For the record, the sound files are mono in wav format, and I use two Macs running 10.10.5. The recordings are mostly recorded on Amadeus Pro and then transferred to Audacity 2.1.2 (downloaded as .dmg and installed on the internal SSD drive).

Audacity takes no part in this. You need calibrated equipment and a lawyer with experience in legally-admissible recordings.

If you leave “Meter dB range” in Interface Preferences at -60 dB this should give you the Y-axis you want.

The X-axis always goes up to half the sample rate of the track. Look at the entire graph not the highest labelled frequency.

If a previous recording shows a highest labelled frequency of 3500 Hz this probably means your track rate or the recording itself is at 8000 Hz sample rate and your newer recording with a maximum label of 20000 Hz is probably at at 44100 Hz sample rate. 44100 Hz would be more expected (it is audio CD quality).

Recordings at different sample rates would I guess not assist legal admissibility.