Nicola Granzotto, Paolo RuggeriProceedings of the Second Vienna Talk, Sept. 19−21, 2010, University of Music and Performing Arts Vienna, Austria VITA-1 DRUM SETS CHARACTERIZATION

Proceedings of the Second Vienna Talk, Sept. 19−21, 2010, University of Music and Performing Arts Vienna, Austria

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DRUM SETS CHARACTERIZATION IN ACOUSTIC LABORATORY

Nicola Granzotto, Paolo Ruggeri

Department of Applied Physics University of Padova, Italy

[email protected]

ABSTRACT

This work presents the measurement results of two drum sets (one for professional use and the other one for beginners use), played by two different drummers, carried out in the Acoustics Laboratory of the Department of Applied Physics of the University of Padova (Italy). The sound power of these drum sets has been evaluated in reverberation room, according to the methods indicated in the ISO 3741 Standard. Six common and simple drum patterns, with different rhythm speed have been played (120 BPM and 60 BPM). Then, some comparisons have been made between the whole sound power level of the drum sets, and each single drum piece of the drum set separately played. The relative third octave bands A-weighted spectrums of six grooves has been calculated in order to calculate spectrum adaptation terms for predicting the A-weighted sound pressure level in a receiving room. According to the methods indicated in the ISO 140-3 Standard [2], sound insulation has been measured using a drum set instead of a omnidirectional source.

1. INTRODUCTION Acoustics drums set instruments produce very high sound pressure level, depending on the type and quality of the drums and cymbals and of the drummer. It depends also by the groove and by the BPM (beat per minute) of the groove.

2. MEASUREMENTS

2.1 Sound power level of acoustic drum sets Sound power level, Lw, of a acoustic source is a characteristic of a source and doesn’t depend on distance and room absorption. The sound power level of acoustic drum sets was determined in laboratory according to ISO 3741 Standard [1]. It is calculated by the following equation:

0 0

427 27310lg 4,34 10lg 1 25lg 6 [ ]8 400 273w p

A A S c BL L dBA S V f Bθ

⎧ ⎫⎡ ⎤⎛ ⎞⋅⎪ ⎪= + + + + − −⎨ ⎬⎢ ⎥⎜ ⎟⋅ ⋅ +⎝ ⎠⎪ ⎪⎣ ⎦⎩ ⎭

(1)

where: Lp is the mean sound pressure level in the reverberation room [dB]; A is the equivalent absorbing area of the room [m2]; A0 =1 m2; S is the surface of the reverberation room [m2]; V is the volume of the reverberation room [m3]; f is the third octave band frequency [Hz]; c is the sound velocity at the temperature θ [m/s]; θ is the temperature [°C]; B is the atmospheric pressure [Pa]; B0 = 101300 [Pa]. For the measurements it has been used a 4 channels Svantek 948 sound analyzer, microphones B&K 4188, microphone

calibrator B&K 4231, power amplifier B&K 2716, omnidirectional source B&K 4295.

2.2 Drums, drummer and grooves For the measurements of the sound power level, two basic drum sets have been used, one for professional use and another one for beginner use, with the following characteristics: Table 1: Description of drum sets Professional drum set Beginners drum set Model SONOR Signature PEARL EX825P Export Drum Bass drum SONOR wood 22”x18” PEARL wood 22”x16” Snare drum SONOR wood 14”x8” PEARL wood 5-1/2” Hi-Hat ZILDJIAN K/Z 13” PEARL Cymbal 14” Ride ZILDJIAN K Custom 20 ” PEARL Cymbal 18”

Figure 1: Basic Drum set in the reverberation room Every drum set was played by two drummers, one with a school background (drummer 1) and the other one self-taught (drummer 2).

Figure 2: Drummer 1 and drummer 2 play Sonor and Pearl drums in the reverberation room Six basic grooves are chosen. Every groove was played at 120 BPM and 60 BPM for 20 seconds. Single piece was also played using the same grooves.

Ride/Crash

Snare Drum

Bass Drum

Hi Hat

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Table 2: Grooves played n° Groove Notation

1 “CHH+SN” (cloded Hi-Hat with snare drum)

2 “OHH+SN” (open Hi-Hat with snare drum)

3 “CHH+SIDE” (cloded Hi-Hat with side stick)

4 “CRASH+SN” (4/4 board cymbal with snare drum)

5 “RIDE+SN” (Ride cymbal with snare drum)

6 “RIDE+SIDE” (Ride cymbal with side stick)

2.3 Experimental results In the following graphics are presented the sound power level of acoustic drum sets, with different groove and BPM.

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120BPM Pearl (1) CHH + SNLw=114,9dB


120BPM Sonor (1) CHH + SNLw=115,7dB




60BPM Sonor (1) CHH + SNLw=113dB


Figure 3: Sound power level of groove 1 at 120 and 60 BPM

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120BPM Pearl (1) OHH +SN Lw=116,1dB

120BPM Pearl (2) OHH +SN Lw=113,7dB

120BPM Sonor (1) OHH +SN Lw=115,9dB

120BPM Sonor (2) OHH +SN Lw=113,7dB

60BPM Pearl (1) OHH + SNLw=113,2dB

60BPM Pearl (2) OHH + SNLw=109,8dB

60BPM Sonor (1) OHH + SNLw=113,2dB

60BPM Sonor (2) OHH + SNLw=111,7dB


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120BPM Pearl (1) CHH +Side Lw=107,2dB

120BPM Pearl (2) CHH +Side Lw=107,7dB

120BPM Sonor (1) CHH +Side Lw=106,9dB


60BPM Pearl (1) CHH + SideLw=103,9dB

60BPM Pearl (2) CHH + SideLw=103,8dB




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120BPM Pearl (1) Crash +SN Lw=117,2dB

120BPM Pearl (2) Crash +SN Lw=115dB

120BPM Sonor (1) Crash +SN Lw=116,7dB


60BPM Pearl (1) Crash + SNLw=114,9dB

60BPM Pearl (2) Crash + SNLw=111,9dB




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120BPM Pearl (1) Ride + SNLw=115,8dB


120BPM Sonor (1) Ride +SN Lw=115,8dB

120BPM Sonor (2) Ride +SN Lw=113,5dB



60BPM Sonor (1) Ride + SNLw=113dB

60BPM Sonor (2) Ride + SNLw=110,9dB


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120BPM Pearl (1) Ride +Side Lw=106,5dB


120BPM Sonor (1) Ride +Side Lw=107,8dB






Figure 8: Sound power level of groove 6 at 120 and 60 BPM In the following graphics are presented an example of time history of the sound pressure level in the reverberation room.

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CHH+SN Pearl (1) 120BPM - Short Leq CHH+SN Pearl (1) 120BPM - LeqCHH+SN Pearl (2) 120BPM - Short Leq CHH+SN Pearl (2) 120BPM - LeqCHH+SN Sonor (1) 120BPM - Short Leq CHH+SN Sonor (1) 120BPM - LeqCHH+SN Sonor (2) 120BPM - Short Leq CHH+SN Sonor (2) 120BPM - Leq

Figure 9: Sound pressure level of groove 1 at 120

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CHH+SN Pearl (1) 60BPM - Short Leq CHH+SN Pearl (1) 60BPM - LeqCHH+SN Pearl (2) 60BPM - Short Leq CHH+SN Pearl (2) 60BPM - LeqCHH+SN Sonor (1) 60BPM - Short Leq CHH+SN Sonor (1) 60BPM - LeqCHH+SN Sonor (2) 60BPM - Short Leq CHH+SN Sonor (2) 60BPM - Leq

Figure 10: Sound pressure levels of groove 1 at 60 BPM It can be noted that different drummers play with different sound power levels. Single drum set piece sound power level has been also measured and summed. It has been found quite the same sound power level of total groove (example of “Ride+SN” in Figure 11).

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10 10 1010 lg 10 10 10 [ ]P BD P SD P RideL L L

sumL dB⎛ ⎞ ⎛ ⎞ ⎛ ⎞⎜ ⎟ ⎜ ⎟ ⎜ ⎟⎜ ⎟ ⎜ ⎟ ⎜ ⎟⎝ ⎠ ⎝ ⎠ ⎝ ⎠

⎛ ⎞⎜ ⎟= + +⎜ ⎟⎝ ⎠

(2)

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Figure 11. Sound power level of groove “Ride+SN” at 120 BPM and the energetic sum of single piece

2.4 Prediction of drums grooves A-weighted sound power level

From the measurements of single piece, it has been calculated the mean single event A-weighted sound power level by two drum sets and two drummers, SELwA, (power level normalized to one second). Table 2: mean single event A-weighted sound power levels by two drum sets and two drummers

Piece

SELwA

Hard Bass Drum 101,4 dB(A) Soft Bass Drum 96,0 dB(A) Snare Drum 109,0 dB(A) Closed Hi Hat 91,3 dB(A) Open Hi Hat 98,7 dB(A) Crash 108,1 dB(A) Ride 98,9 dB(A) Side Snare Drum 100,4 dB(A)

Single event, SELwA, can be used to estimate global A-weighted sound power level of a drum groove using the following equation:

10lg240

10

_ 10 lg 10 [ ( )]

wAiE BPMSEL

TS

wA groove iL dB A

⋅⎛ ⎞⎛ ⎞+⎜ ⎟⎜ ⎟⋅⎝ ⎠⎜ ⎟⎜ ⎟⎜ ⎟⎝ ⎠

⎛ ⎞⎜ ⎟⎜ ⎟

= ⎜ ⎟⎜ ⎟⎜ ⎟⎝ ⎠

∑

(3)

where: SELwAi is the single event A-weighted sound power level [dB(A)]; E is the number of musical event in a measure; BPM is beat per minute; TS is the time signature. For example for a heavy metal groove (Figure 12) at 130 BPM with 16/16 double bass drum, we can estimate the global sound power level by this:

16 130 4 130 8 130101,4 10lg 109,0 10lg 91,3 10lg240 1 240 1 240 1

10 10 10

10lg 10 10 10

114,7 [ ( )]

wAL

dB A

⋅ ⋅ ⋅⎛ ⎞ ⎛ ⎞ ⎛ ⎞⎛ ⎞ ⎛ ⎞ ⎛ ⎞+ + +⎜ ⎟ ⎜ ⎟ ⎜ ⎟⎜ ⎟ ⎜ ⎟ ⎜ ⎟⋅ ⋅ ⋅⎝ ⎠ ⎝ ⎠ ⎝ ⎠⎜ ⎟ ⎜ ⎟ ⎜ ⎟⎜ ⎟ ⎜ ⎟ ⎜ ⎟⎜ ⎟ ⎜ ⎟ ⎜ ⎟⎝ ⎠ ⎝ ⎠ ⎝ ⎠

⎛ ⎞⎜ ⎟⎜ ⎟

= + + =⎜ ⎟⎜ ⎟⎜ ⎟⎝ ⎠

=

(4)

Figure 12. Heavy metal groove

2.5 Sound reduction index measurements Measurements of sound reduction index, R, of a wall were taken using an omnidirectional source, according to ISO 140 part 3 Standard [2], and a drum set with “CHH+SN” (groove 1). R is calculated by the following equation:

1 2 10 lg [ ]SR L L dBA

⎛ ⎞= − + ⎜ ⎟⎝ ⎠

(5)

where: L1 is the mean sound pressure level in the transmitting room [dB]; L2 is the mean sound pressure level in the receiving room [dB]; A is the equivalent absorbing area of the receiving room [m2]; S is the surface of the separating wall [m2].

Figure 13: Measurement of sound reduction index of a wall using omnidirectional sound source and using drums set (groove 1 in transmitting room).

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Figure 14: Sound reduction index of a wall using omnidirectional sound source or drums set The weighted sound redution index was Rw(C;Ctr)=58(-3;-10) for both source, so sound reduction index doesn’t depend on the drums sound.

2.6 Drums grooves spectrum adaptation terms It has been found that the frequency distribution of sound power levels dosen’t change very much by changing BPM, and drummers (Figure 15).

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Figure 15: Example of sound power level changing BPM and drummers So, average sound power levels of the six grooves have been calulated (Figure 16) to find normalised to 0 dB spectrums (Figure 17). This is useful for “drums grooves spectrum adaptation terms” calculation, we call this parameter “Cdr” in analogy with ISO 717-1 method [3].

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Figure 16: Average sound power level of different gooves

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Figure 17: Relative spectrums (normalized to 0 dB) for “drums grooves spectrum adaptation terms” calculation We can use Rw+”Cdr” to estimate A-weighted sound pressure level in a receiving reverberant room, or to choose the best wall for sound insulation (for example if we have to project a drums insulation box, we haven’t to choose only the higher Rw value but we have to choose the higher Rw+”Cdr” value). The weighted sound reduction index, Rw, of 58 dB and “Cdr” of -8 dB has been measured for a light wall in laboratory and groove 1. In the transmitting and receiving room, the A-weighted sound pressure levels of respectively 108,1 dB(A) and 58,4 dB(A) has been measured. Predicted A-weighted sound pressure levels in the receiving room, Lp2(A), is:

1( ) ( " ") 108,1 (58 8) 58,1 [ ( )]p w drL A R C dB A− + = − − = (6) well according to measurements.

3. CONCLUSIONS The comparison between two drums sets played by two drummers show a relation between sound power level and BPM. In fact, doubling the BPM sound power level increase up to 3. It is noted that adding sound power level of single piece get the sound power level of entire groove. It has been calculated the mean single event A-weighted sound power level, SELwA, to predict the A-weighted sound power level of any groove. It is find sound power level of different groove and six normalized to 0 dB spectrum for “drums grooves spectrum adaptation terms” calculation useful for predicting sound pressure level in a receiving room produced by a particular drums groove in a transmitting room or to choose the best wall for a particular groove.

4. REFERENCES [1] ISO 3741 Acoustics. Determination of sound power

levels of noise sources using sound pressure. Precision methods for reverberation rooms.

[2] ISO 140-3 Acoustics. Measurement of sound insulation

in buildings and of building elements. Part 3: Laboratory measurements of airborne sound insulation of building elements.

[3] ISO 717-1 Acoustics. Rating of sound insulation in

buildings and of building elements. Part 1: Airborne sound insulation.

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Nicola Granzotto, Paolo RuggeriProceedings of the Second Vienna Talk, Sept. 19−21, 2010, University of Music and Performing Arts Vienna, Austria VITA-1 DRUM SETS CHARACTERIZATION

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