# Design and Application of the BiVib Audio-Tactile Piano Sample Library
## 2 Creation of the BiVib library
### Recording Hardware  
The samples were recorded from two Yamaha Disklavier pianos--a grand model DC3 M4 located in Padova (PD), Italy, and an upright model DU1A with control unit DKC-850 located in Zurich (ZH), Switzerland. Disklaviers are Musical Instrument Digital Interface (MIDI from here on)-compliant acoustic pianos equipped with sensors for recording keystrokes and pedaling, and operating electromechanical motors for playback. The grand piano is located in a large laboratory space (approximately \(6\times 4\) m), while the upright piano is in an acoustically treated small room (approximately \(4\times 2\) m).  
\begin{table}
\begin{tabular}{l l l} \hline \hline  & **Disklavier Grand** & **Disklavier Upright** \\ \hline \multirow{3}{*}{**Sample sets** (. wav files)} & Binaural (closed) & Binaural (closed) \\  & Binaural (open) & Binaural (semi-open) \\  & Binaural (removed) & Binaural (open) \\  & Keyboard vibration & Keyboard vibration \\ \hline \multirow{3}{*}{**Sampler projects** (Kontakt _multilis_)} & Binaural (closed) + vibration & Binaural (closed) + vibration \\  & Binaural (open) + vibration & Binaural (semi-open) + vibration \\ \cline{1-1}  & Binaural (removed) + vibration & Binaural (open) + vibration \\ \hline \hline \end{tabular}
\end{table}
Table 1: Binaural and vibratory (BiVib) core structure. Piano lid configurations are given in square brackets.  
Binaural audio recordings made use of dummy heads for acoustic measurements, with slightly different setups in PD and ZH: the grand piano was recorded with a KEMAR 45 BM (GRAS Sound & Vibration A/S, Holte, Denmark), whereas the upright piano with a Neumann KU 100 (Georg Neumann GmbH, Berlin, Germany). Both mannequins were placed in front of the pianos, approximately where the pianist's head is located on average (see Figure 1).  
The dummy heads were connected to the microphone inputs of two professional audio interfaces, a RME Fireface 800 (PD, gain set to \(+40\) dB) (Audio AG, Haimhausen, Germany) and a RME UCX (ZH, gain set to \(+20\) dB) (Audio AG, Haimhausen, Germany). The pair of condenser microphones inside the dummy heads were respectively driven by two 26 CB preamplifiers supplied by a 12 AL power module (PD), and by 48V phantom power provided by the audio interface (ZH).  
Three configurations of the keyboard lid were selected for each piano. The grand piano (PD) was measured with the lid closed, fully open, and removed (i.e., detached from the instrument). The upright piano was recorded with the lid closed, in semi-open position (see Figure 1), and fully open. Different lid configurations in fact add insight on the role of the mechanical noise coming from the moving keys to the creation of transient cues of lateralization in the sound field reaching the performer's ears [30]. As a result, three sets of binaural samples were recorded for both pianos--one set for each lid position.  
Vibration recordings were acquired with a Wilcoxon Research 736 (Wilcoxon Sensing Technologies Inc., Amphenol, MD, USA) piezoelectric accelerometer connected to a Wilcoxon Research iT100M (Wilcoxon Sensing Technologies Inc., Amphenol, MD, USA) intelligent transmitter, whose AC-coupled output fed one line input of the audio interface. The accelerometer was manually attached with double-sided adhesive tape to each key in sequence, as shown in Figure 2. Its center was positioned 2 cm far from the key edge, where most vibration modes are radiated efficiently, and where pianists typically put their fingertip.  
Figure 1: Binaural audio recording setup in Zurich (ZH). Piano lid in ‘semi-open’ position.