Dear cemprotecta,
We are in danger of confusion from poor terminology. I’ve had a look at the PDF documents you’ve posted so let me clarify (if I can).
All decibels are logarithmic as Ken has stated, but dBL has no WEIGHTING applied. dBA for example has a weighting applied to adjust the frequency response to mimic the human ear so that the same dBA at different frequencies sound the same loudness to the human ear. The documents you refer to seem to use the terms weighting and filter interchangably. Normal practice in seismology and related fields is to refer to filters as a limit in bandwidth of the signal (i.e. low pass, highpass or bandpass).
A RS&B can produce the UNWEIGHTED decibels (dBL if you like) you require up to a maximum frequency of 50Hz. For example, refer to the latest version of the python report here:
Note that while developing this report some errors were found in the Raspberry Shake and Boom Manual which has since been corrected. The code for converting counts to Pascals and Pascals to dB are detailed there as well.
The only concern I would raise - again this is purely based on terminology - is that the dBL definition clearly states “unfiltered, and represents the full spectrum of incoming noise”. If this means no weighting, and no missing frequencies from the available bandwidth, then everything is fine. If the “full spectrum” means the full spectrum of human hearing (20Hz to 20,000Hz) then clearly infrasound (<20Hz) does not apply and RS&B data does not apply as the RS&B is limited to <50Hz. This might seem pedantic, but if the reason for you wanting the data is, or turns into, a legal one, this will become a legal point of debate IMO so expect that one. ;o)
Al.