# A Progressively Expanded Database for Automated Lung Sound Analysis: An Update
## 2 Materials and Methods
### Lung Sound Recordings  
We used two different devices to record the participants' lung sounds. The first device was a commercial handheld electronic stethoscope, Littmann 3200 (3M, Saint Paul, MN, USA); the second one was a customized auscultation device, HF-Type-1 [18], which supported multichannel continuous sound recording through attachable acoustic sensors. We followed the same recording protocols described in our previous study to acquire the lung sounds from the participants [18]. Eight auscultation locations (Figure 1a) were firstly defined--L1: second intercostal space (ICS) on the right midclavicular line (MCL); L2: fifth ICS on the right MCL; L3: fourth ICS on the right midaxillary line (MAL); L4: tenth ICS on the right MAL; L5: second ICS on the left MCL; L6: fifth ICS on the left MCL; L7: fourth ICS on the left MAL; and L8: tenth ICS on the left MAL. Briefly, when the Littmann  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{1}{c}{**Subjects from RCC/RCW**} & \multicolumn{1}{c}{**Subjects from FEMH**} & \multicolumn{1}{c}{\
\begin{tabular}{c} **Subjects in TSECCM** \\ **Database** \\ \end{tabular} } \\ \hline Number (n) & 25 & 32 & 243 \\ \hline Sex (M/F/NA) & 16/8/1 & 19/13 & NA \\ \hline Age & 64.5 \(\pm\) 18.5 & 68.2 \(\pm\) 11.7 & NA \\ \hline Height (cm) & 162.3 \(\pm\) 9.1 * & 160.0 \(\pm\) 8.8 & NA \\ \hline Weight (kg) & 63.4 \(\pm\) 12.7 * & 59.7 \(\pm\) 12.3 & NA \\ \hline BMI (kg/m\({}^{2}\)) & 24.0 \(\pm\) 4.3 * & 23.6 \(\pm\) 4.6 & NA \\ \hline Recording device &
\begin{tabular}{c} HF-Type-1 \& \\ [PERSON] 3200 \\ \end{tabular} & [PERSON] 3200 & [PERSON] 3200 \\ \hline \multicolumn{4}{c}{Respiratory disease} \\ \hline Acute exacerbation of chronic & 1 (4\%) & 1 (3\%) & NA \\ obstructive pulmonary disease & 1 (4\%) & 0 (0\%) & NA \\ \hline Acute respiratory failure & 4 (16\%) & 0 (0\%) & NA \\ \hline Asthma & 0 (0\%) & 1 (3\%) & NA \\ \hline Bronchitis & 1 (4\%) & 0 (0\%) & NA \\ \hline Chronic respiratory failure & 12 (48\%) & 2 (6\%) & NA \\ \hline Chronic obstructive pulmonary disease & 2 (8\%) & 5 (16\%) & NA \\ \hline Emphysema & 1 (4\%) & 0 (0\%) & NA \\ \hline Pleural effusion & 0 (0\%) & 1 (3\%) & NA \\ \hline Pneumoconiosis & 0 (0\%) & 1 (3\%) & NA \\ \hline Pneumonia & 6 (24\%) & 7 (22\%) & NA \\ \hline Pulmonary embolism & 0 (0\%) & 1 (3\%) & NA \\ \hline \hline \end{tabular}  
* With four missing data. NA: not available.  
\end{table}
Table 1: Demographic data and the characteristics of respiratory diseases of the subjects in HF_Lung_V2.  
3200 device was used, to complete a standard round of recording, lung sounds must be ausculated sequentially from L1 to L8 (white arrows in the top graph in Figure 1b). When the HF-Type-1 device was used, acoustic sensors were attached at L1, L2, L4, L5, L6, and L8, and lung sounds were continuously recorded at the same time. A standard round of lung sound recording with the HF-Type-1 device consisted of the acquisition of continuous signals from each of these six locations over 30 min (white arrows in the bottom graph in Figure 1b).  
The lung sounds of the seven RCW/RCC inpatients were obtained with the Littmann 3200 device for 4-5 rounds and the HF-Type-1 device for 3-4 rounds. The lung sounds of the 32 inpatients at FEMH were recorded using the Littmann 3200 device alone for 1-3 rounds. The sampling rate of the recording devices was 4000 Hz, and the bit depth was 16 bits. We did not ask the participants to take deep breaths during sound recording.