Acoustics of a Music Venue/Bar—A Case Study

buildings

Article Acoustics of a Music Venue/Bar—A Case Study

Ramani Ramakrishnan *,† and Romain Dumoulin † Department of Architectural Science, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada; [email protected] * Correspondence: [email protected]; Tel.: +1-416-979-5000 (ext. 6508); Fax: +1-416-979-5353 † These authors contributed equally to this work.

Academic Editor: David Arditi Received: 1 February 2016; Accepted: 11 March 2016; Published: 16 March 2016 Abstract: A vacant unit, once used by a Portuguese Deli, was converted to a bar/music room in Toronto. The unit was divided into two spaces along its north-south axis. The western portion was designed as a music room that would provide a performance space from a solo artist to a Jazz combo to a small rock band. The eastern part was designed as a regular bar/dining area. The plan also called for a microbrewery unit at the back of the unit. The bar music can be loud, while the music room can be pianissimo to forte depending on the type of performance. The acoustical design aspects are critical for the music room. In addition, the acoustical separation between the two spaces is equally important. The music room/bar is currently in use. The design results are compared to actual ﬁeld measurements. The results showed that the music venue performed satisfactorily. The acoustical separation between the music venue and the bar/restaurant was better than expected other than an installation deﬁciency of the south side sound lock doors. The background sound along the northern portion was NC-35 or less. However, the southern portion’s background sound exceeded NC-35 due to the hissing of the return air grille. The acoustical design and the performance results of the music venue-bar/restaurant are presented in this paper.

Keywords: music room; bar; acoustical metrics; acoustical separation; HVAC (Heating, Ventilation and Air-Conditioning) system noise

1. Introduction The acoustics of a space is seldom considered when designing a bar or a restaurant. Even the noise intrusion from the bar into adjoining spaces is not recognized and attended to, only if there are complaints. Many small music venues do not undertake a proper acoustical study and only implement minor fixes after the fact. Acoustical consultants face myriad obstacles when requested to provide design guidelines during the initial stages of the venue planning. Cost and implementation difficulties are excuses used to thwart the acousticians. Similarly, when the small music venues face acoustical deficiencies after the facilities are constructed, the owners do not always offer a free hand to the acousticians to satisfactorily resolve the acoustical concerns. In contrast to the conventional modus operandi, two partners with strong musical background, decided to convert a defunct deli into a music room/bar-restaurant facility at a major intersection in Toronto. As musicians, they understood the seriousness of their plans from an acoustical perspective. The acousticians were given total freedom to provide proper design solutions from different aspects of acoustics such as room acoustics and noise separation. The two spaces were designed using conventional prediction schemes and implementation details were appropriately prescribed. Preliminary details and results from site measurements were presented in Ramakrishnan and Dumoulin [1]. Vigeant et al. investigated different test methods to determine the JND (Just Noticeable Difference) for the clarity metric C80 [2]. The current case study has evaluated the relative errors of different

Buildings 2016, 6, 11; doi:10.3390/buildings6010011 www.mdpi.com/journal/buildings Buildings 2016, 6, 11 2 of 13 acoustic metrics by using the subjective limen calculations. The JND evaluation of Reference [3] is Buildings 2016, 6, 11 2 of 13 somewhat similar to the current investigation. differentPatania etacoustic al. investigated, metrics by using through the subjective simulation, limen the calculations. acoustic of The a music JND evaluation hall in a heritage of Reference building in University[3] is somewhat of Catania, similar Italyto the and current provided investigatio methodsn. to improve its acoustic quality [3]. Orlowski conductedPatania a series et al of. investigated, measurements through to evaluate simulation, the the reverberation acoustic of a music time hall and in strength a heritage in building a number of musicinrooms University [4]. Noceraof Catania,et al Italy. investigated and provided the methods lecture hall to improve of steel constructionits acoustic quality and provided [3]. Orlowski methods to improveconducted its a acoustic series of qualitymeasurements [5]. Similar to evaluate investigations the reverberation were undertakentime and strength in the in currenta number study of to music rooms [4]. Nocera et al. investigated the lecture hall of steel construction and provided methods provide suitable acoustical designs for the conversion of a delicatessen into a music room. to improve its acoustic quality [5]. Similar investigations were undertaken in the current study to The two facilities were constructed and became operational in early 2015. Detailed site provide suitable acoustical designs for the conversion of a delicatessen into a music room. measurementsThe two were facilities conducted were and constructed the ﬁnished and facilitybecame was operational remodeled in early using 2015. ODEON Detailed software site [6]. The resultsmeasurements of the comparisons were conducted between and the simulation finished facility and sitewas measurementsremodeled using are ODEON presented software in this [6]. paper. DetailedThe results results of of the the comparisons simulation between are also simulation presented and in site this measurements paper. are presented in this paper. Detailed results of the simulation are also presented in this paper. 2. Background 2. Background The proposed, but preliminary, lay out details of the music venue/bar-restaurant, on Bloor Street, Toronto,The are proposed shown in, but Figure preliminary,1. The lay unit out was details divided of the musi intoc two venue/bar spaces-restaurant, along its on north-south Bloor Street, axis. The westernToronto, portionare shown was in Figure designed 1. The as unit a music was divided room, into with two an spaces approximate along its volumenorth-south of 230 axis. cu.m, The that western portion was designed as a music room, with an approximate volume of 230 cu.m, that would would provide a performance space for a solo artist to a Jazz combo to a small rock band. The eastern provide a performance space for a solo artist to a Jazz combo to a small rock band. The eastern part part was designed as a regular bar/dining area. The bar music can be loud, while the music room can was designed as a regular bar/dining area. The bar music can be loud, while the music room can be be pianissimopianissimo to to forte forte dependingdepending on on the the type type of of performance. performance. The The plan planss also also called called for a formicrobrewery a microbrewery unit atunit the at norththe north end end of theof the facility. facility.

[Large Window] [Sound Lock Doors] [Music-Venue] [Bar/Restaurant] [Stage] [Microbrewery] (a)

(b)

Figure 1. Music venue/bar layout. (a) Perspective view; (b) Plan with dimensions. Buildings 2016, 6, 11 3 of 13

Music Venue/Bar Requirements Two different types of needs were considered during the design: (a) Unreinforced concerts with acoustical instruments; and (b) music using sound reinforcement system. The main acoustical requirements were: (i) adequate loudness in every part of the room; (ii) uniform distribution of sound pressure levels; (iii) optimum reverberation for music; (iv) free from acoustical defects (such as echoes); and (v) low background noise levels and vibration. The acoustical parameters used to evaluate the quality of the venue acoustics were: reverberation time (T30); and clarity (C80). It must be noted that only the above two metrics and expected sound level distribution were investigated for preliminary design details of the music venue. The optimum acoustical parameters for the venue according ISO standards and well known recommendations are summarized in Table1 below [7–11].

Table 1. Optimum acoustical parameters for an empty musical space.

Condition T30, s C80, dB dBA Unreinforced music 0.8–1.0 >´5 >80 * Reinforced music 0.6 – 90–100 Notes: dBA is the overall sound pressure level from the activity. * Preferred overall sound pressure levels for classical music.

In addition, adequate acoustical separation must be provided between the bar and the music venue. The bar sound levels must be controlled with a limiter and overall sound levels in the bar-restaurant area should not exceed 85 dBA and 90 dB. It can be seen therefore that an Apparent Sound Transmission Class (ASTC) of around 50 is an adequate separation for the construction between the music venue and the bar.

3. Proposed Design The microbrewery is located along the north end of the unit. The east wall faces a side street and there is a gap along the west wall. In addition the second level of the complex has three rental apartments. And hence, it must be pointed out that the interior acoustical design is as important as the design of appropriate separation so that the noise intrusions can be kept to a minimum. Finally, the HVAC system noise levels must be adequately silenced. The details of the design are outlined in the following sections.

3.1. Interior Acoustical Design The music venue is long and narrow with a large window on the south wall. The stage area is at the north end with the musicians on an elevated platform. It will be utilized for three different events: solo musician (with and without amplification); a small group such as a jazz band (with and without amplification); and a rock band (with amplification). The three event scenarios were modeled in the acoustical software. The results showed that the solo musician might need some amplification. Jazz Band can be loud enough without amplification. The Rock band uses amplification. Since the space is narrow and long, it needs diffusers to aid in the propagation and assist in the diffusivity of the sound. Approximately 50 square metres of diffusers were to be applied in the acoustical simulations and a few diffuser options, as shown in Figure2 below, were proposed. One of the main requirements is to install heavy valour drapes, operable, over the south window and behind the stage for two reasons: (a) to prevent echoes from the window; and (b) to add acoustical absorption to the room when sound amplification is used. Moveable absorbing curtains and a treated ceiling were recommended for the stage area in order to reduce the risks of acoustical feedback when microphones are used for sound reinforcement. Buildings 2016, 6, 11 4 of 13 Buildings 2016, 6, 11 4 of 13 Buildings 2016, 6, 11 4 of 13

(a) (b) (c) (a) (b) (c) Figure 2. Diffuser design options. (a) Polycylindrical diffusers; (b) 2D random pattern diffuser; FigureFigure 2. 2.Diffuser Diffuser design design options. options. (a) Polycylindrical d diffusers;iffusers; (b (b) )2D 2D random random pattern pattern diffuser; diffuser; (c) Pyramidal diffuser. (c)( Pyramidalc) Pyramidal diffuser. diffuser. The location of the speakers and sub-woofers are very critical to overcome low-frequency modal TheThe location location of of the the speakers speakers and and sub-woofers sub-woofers are very critical critical to to overcome overcome low low-frequency-frequency modal modal distribution in the music room and appropriate locations were recommended. distributiondistribution in in the the music music room room and and appropriate appropriate locationslocations were recommend recommended.ed. Finally, the speakers for the Bar music are to be hung by spring hangers from the main ceiling Finally,Finally, the the speakers speakers for for the the Bar Bar music music areare toto bebe hunghung by spring hange hangersrs from from the the main main ceiling ceiling joist and the levels are controlled to be less than 85 dBA and 90 dB (linear). The limiter to be used for joist and the levels are controlled to be less than 85 dBA and 90 dB (linear). The limiter to be used for joistthe and bar themusic levels must are include controlled a microphone to be less to than measure 85 dBA the and bar 90noise dB levels. (linear). The limiter to be used for thethe bar bar music music must must include include a a microphone microphone to to measure measure thethe barbar noise levels. levels. 3.2. Acoustical Separation 3.2.3. Acoustical2. Acoustical Separation Separation A floating floor assembly was used for the music venue. Baltic birch board, ¾” thick, was floor A floating floor assembly was used for the music venue. Baltic birch board, ¾” thick, was floor mountedA floating on rubber floor assembly-in-shear mounts was used as shown for the below music in venue. Figure Baltic3. birch board, ¾” thick, was floor mountedmounted on on rubber-in-shear rubber-in-shear mounts mounts as as shown shown belowbelow inin Figure 33..

Figure 3. Floating floor assembly details for the music venue. FigureFigure 3. 3.Floating Floating floorfloor assemblyassembly details for the the music music venue. venue. Two wall assemblies will separate the music venue and the bar. Each wall assembly is two layers Two wall assemblies will separate the music venue and the bar. Each wall assembly is two layers of Twodrywall wall (5/8 assemblies′′ thick) and will is separateon separate the metal music studs. venue The and spacing the bar. between Each wall the assemblystuds was ischosen two layers to of drywall (5/811′′ thick) and is on separate metal studs. The spacing between the studs was chosen to offit drywall the space. (5/8 Thethick) air-gap and between is on separate the two metal studs studs.is filled The with spacing batt insulation. between theThe studsre are wastwo chosenwall fit the space. The air-gap between the two studs is filled with batt insulation. There are two wall toassemblies fit the space. for Thethe music air-gap venue: between one thethat two separates studs the is filled bar and with the batt other insulation. one is next There to the are exterior two wall assemblies for the music venue: one that separates the bar and the other one is next to the exterior assemblieswall. Both for the the wall music assemblies, venue: oneincluding that separates the studs the were bar placed and the on otherthe floating one is floor. next to The the studs exterior of the wall. wall. Both the wall assemblies, including the studs were placed on the floating floor. The studs of the Bothwall the assembly wall assemblies, next to the includingexterior wall the were studs connected were placed through on partition the floating supports floor. such The as studs sway ofbraces. the wall wall assembly next to the exterior wall were connected through partition supports such as sway braces. assemblyThe next ceiling to the of exterior the two wall spaces were were connected designed through as a membrane partition supports system to such provide as sway separation braces. The ceiling of the two spaces were designed as a membrane system to provide separation between the two spaces as well as to adequately separate the spaces from the apartments above. betweenThe ceiling the two of the spaces two spacesas well were as to designed adequately as aseparate membrane the systemspaces tofrom provide the apartments separation above. between Details of typical membrane system are shown in Figure 4 below. Note: The T-Bar system shown in theDetail two spacess of typical as well membrane as to adequately system are separateshown in theFigure spaces 4 below. from N theote: apartments The T-Bar system above. shown Details in of Figure 4 was not part of the current design. The music venue’s ceiling consisted of a 3-layer gypsum typicalFigure membrane 4 was not system part of arethe showncurrent indesign. Figure The4 below. music Note: venue The’s ceiling T-Bar consisted system shown of a 3- inlayer Figure gypsum4 was board with each layer’s taping staggered from the adjacent layers and were connected to the main notboard part ofwith the each current layer design.’s taping The staggered music venue’sfrom the ceiling adjacent consisted layers and of awere 3-layer connected gypsum to boardthe main with slab through resilient hangars. On the other hand, the celling of the bar-restaurant, due to space eachslab layer’s through taping resilient staggered hangars. from On the the adjacent other hand, layers the and celling were of connected the bar-restaurant, to the main due slab to through space limitation, consisted of a double layer gypsum board construction and were connected to the slab resilientlimitation, hangars. consisted On the of other a double hand, layer the cellinggypsum of board the bar-restaurant, construction and due were to space connected limitation, to the consisted slab above through resilient “z” channels. of aabove double through layer resilient gypsum “ boardz” channels. construction and were connected to the slab above through resilient The music venue and the bar share two sets of doors, one near the stage of the music venue and “z” channels.The music venue and the bar share two sets of doors, one near the stage of the music venue and the other is near the raised portion of the music venue, as shown in Figure 1. Both doors, of each set, theThe other music is near venue the raised and the portion bar share of the two music sets venue, of doors, as shown one near in Figure the stage 1. Both of the doors music, of venueeach set, and was solid core and one of them had an STC 47 rating. Finally, the HVAC system details were assessed was solid core and one of them had an STC 47 rating. Finally, the HVAC system details were assessed theand other appropriate is near the silencers raised portionwere recommended of the music so venue, the music as shown venue in ambient Figure1 .sound Both doors,levels were of each less set, and appropriate silencers were recommended so the music venue ambient sound levels were less wasthan solid NC core-35 ( andNC is one Noise of them Criterion had anCurves STC) 47. rating. Finally, the HVAC system details were assessed andthan appropriate NC-35 (NC silencers is Noise were Criterion recommended Curves). so the music venue ambient sound levels were less than NC-35 (NC is Noise Criterion Curves). Buildings 2016, 6, 11 5 of 13

Buildings 2016, 6, 11 5 of 13 Buildings 2016, 6, 11 5 of 13 A few images of the completed music room are shown in Figure5 below. Wall design as diffusers A few images of the completed music room are shown in Figure 5 below. Wall design as diffusers andand the A locationthe few location images of theof of the the stage stage completed speakers speakers music are are highlighted roomhighlighted are shown in Figure in Figure 5.5. 5 below. Wall design as diffusers and the location of the stage speakers are highlighted in Figure 5.

Figure 4. Membrane ceiling details. Figure 4. Membrane ceiling details. Figure 4. Membrane ceiling details.

(a) (b) (a) (b)

(c) (d) (c) (d) Figure 5. The built music room. (a) East wall diffuser; (b) West wall diffuser; (c) Stage speakers; and Figure(d) Music 5. The room built looking music nor room.th. (a) East wall diffuser; (b) West wall diffuser; (c) Stage speakers; and Figure 5. The built music room. (a) East wall diffuser; (b) West wall diffuser; (c) Stage speakers; and (d) Music room looking north. (d) Music room looking north. The diffusers correspond to a relaxed architectural adaptation of maximum length sequence diffusersThe diffuserswith vertical correspond and horizontal to a relaxed wells. architectural While perfectly adaptation uniform of diffusion maximum was length not needed, sequence the diffusersmainThe objective diffusers with vertical for correspond the seand diffusers horizontal to a was relaxed wells.to diffuse architecturalWhile early perfectly lateral adaptation uniformreflections. diffusion of The maximum location was not of length needed,the speakers sequence the diffusersmain objective with vertical for the andse diffusers horizontal was wells.to diffuse While early perfectly lateral reflections. uniform The diffusion location was of the not speakers needed, the main objective for these diffusers was to diffuse early lateral reflections. The location of the speakers Buildings 2016, 6, 11 6 of 13 and sub-woofers are very critical to control the acoustic energy delivered from speakers to room modes. In order to limit the first three orders of the axial modes (for the venue’s width and height axes) to be energized, appropriate locations of the subwoofers were recommended—25% of the room width from each wall and elevated at 25% of the room height from the floor, which correspond to the null locations for the second-order standing waves. Simple room acoustic simulations were not undertaken since the main frequencies around 125 Hz were below the Schroeder cut-of frequency limit for the simulation software. Note: If one needs an accurate representation in low frequencies, FEM (Finite Element Modelling) simulation would have to be undertaken, which is beyond the scope of the current study.

4. Acoustical Modelling The final design of the room was modelled in ODEON simulation tool for comparison purposes [2]. Two scenarios were applied to generate acoustical metrics along a grid, at a height of 1.5 m, representing the audience space. The audience space of the music room consisted of two areas: (a) the audience, seated, in the northern half; and (b) the audience, standing, near the southern portion. The grid simulations were undertaken for the fully occupied room and for the empty room. In addition, four individual locations were chosen to generate the acoustical parameters for an empty room so as to provide comparison results with site measurements, to be discussed subsequently in Section6. The results of the reverberation time from the site measurements were used to calibrate the simulation models. A large set of parameters were generated by simulation as well as calculations from impulse measurements. Detailed definitions and acceptable range of values for the acoustical parameters can be found in Barron [10] and Rossing [11]. The following parameters will be evaluated and discussed in this paper. Note: The relationship between subjective parameters and objective acoustical metrics such as T60, EDT, C80, and Ts have been dealt with in detail by a number of researchers and can be found in References [9–11]. And hence only their brief definition are highlighted below.

1. Reverberation Time, T60—represents the amount of reverberance of the space; 2. Early Decay Time, EDT—represents the amount of reverberance of the space and is better correlated with reverberance than RT60; 3. Clarity, C80—describes the degree of perception of the details of the performance; 4. Centre Time, Ts—describes the balance between early and late sound and hence evaluates the balance between clarity and reverberance; 5. SPL (Sound Pressure Level) Variation—describes how the sound is distributed throughout the space. The absolute values are not critical and one should look only at its variation.

Finally, the echo potential is evaluated by using the methods of Dietsch and Kraak [12]. The simulations of the room requires acoustical parameters such as absorption coefficients of the interior materials. These values are obtained from the database of the simulation software as well as published materials such as those provided by Adelman-Larson et al.[13]. The scattering coefficients, in particular for wood diffuser walls and audience were obtained from Zeng et al.[14]. The above values were adjusted while calibrating the simulation models with measured data from impulse measurements (Section 5.3). A set of sample results, RT60 (based on T(30) averaged T(30), and SPL variation, of the simulations are presented in Figure6 through 8. Reverberation time results for the full and empty rooms, at 500 Hz, are shown in Figure6. The variation across the room is insignificant. The reverberation time reduced from 0.8 s for the empty room to 0.55 s for the full room. The reduced reverberation falls within the design goal set for the music room with sound amplification. The SPL variation at 500 Hz for the fully occupied and empty room scenarios are shown in Figure7. In the case of a small group with amplification only on the stage, the SPL variations are of the order of 9 dB for the fully occupied room and 7 dB for the empty room. However, the SPL variation for the front half of the room is 3.5 dB for the full room and 2.5 dB for the empty room. The lack of Buildings 2016, 6, 11 7 of 13

Buildings 2016, 6, 11 7 of 13 uniform distribution near the back of the music room was highlighted during the initial design and it was recommended that sound amplification was to be implemented. The final plan of the music room Buildingsand it was 2016 ,recommended 6, 11 that sound amplification was to be implemented. The final plan of the 7music of 13 included two ceiling mounted speakers, in the centre of the room and provided additional sound for room included two ceiling mounted speakers, in the centre of the room and provided additional the back portion of the room, as shown in Figure5d. andsound it was for recommended the back portion that of sound the room, amplification as shown was in Figure to be implemented. 5d. The final plan of the music roomThe Theincluded results results two of of average averageceiling reverberationm reverberationounted speakers, time time is inis presented presentedthe centre in inof Figure Figurethe room8 below.8 below. and The provided The variation variation additional of of the the reverberationsoundreverberation for the time back time is portion is similar similar of to theto that that room, of of 500 500as Hz. shown Hz. The The averagedin averagedFigure value5d. value reduced reduced from from 0.8 s0.8 (empty s (empty room) room) to 0.5to s0.5 (fullyThe s (fully results occupied occupied of average room). room). Thereverberation The reduced reduced reverberation time reverberation is presented falls falls withinin within Figure the the 8 design below.design goal Thegoal set variationset for for the the musicof music the roomreverberationroom with with sound sound time amplification. amplification.is similar to that of 500 Hz. The averaged value reduced from 0.8 s (empty room) to 0.5 s (fully occupied room). The reduced reverberation falls within the design goal set for the music room with sound amplification.

(a) (b)

Figure 6. RT60 variation at 500 Hz for the music room. (a) Empty; (b) Fully occupied. Figure 6. RT60 variation(a) at 500 Hz for the music room. (a) Empty; (b) Fully(b) occupied.

Figure 6. RT60 variation at 500 Hz for the music room. (a) Empty; (b) Fully occupied.

(a) (b)

Figure 7. Sound Pressure Level(a) (SPL) variation at 500 Hz for the music room. (a) Empty;(b) (b) Fully occupied.

FigureFigure 7. Sound 7. Sound Pressure Pressure Level ( LevelSPL) variation (SPL) variation at 500 Hz at for 500 the Hzmusic for room. the music (a) Empty; room. (b) Fully (a) Empty; occupied. (b) Fully occupied. Buildings 2016, 6, 11 8 of 13 Buildings 2016, 6, 11 8 of 13

(a) (b)

FigureFigure 8. AAverageverage T(30) variatio variationn for the music r room.oom. ( a) Empty; ( b) Fully occupied.occupied.

FFinally,inally, the simulation results showed the following values, of the remaining acoustical parameters, for for a a fully fully occupied occupied room room at at 500 500 Hz Hz:: (a) (a) C80 C ranged80 ranged between between 3 dB 3 and dB and8 dB; 8 ( dB;b) T (b)s was Ts betweenwas between 25 ms 25 to ms 65 to ms; 65 and ms; and(c) EchoDietsch (c) EchoDietsch values values were were between between 0.39 0.39and and0.49. 0.49. And And hence, hence, it can it becan concluded be concluded that that the themusic music room room had had been been designed designed to to provide provide more more than than satisfactory satisfactory acoustical acoustical conditions. N Note:ote: EchoDietsch EchoDietsch values values have to be higher than 0.9 to cause any concerns.

55.. Site Site Measurements Measurements The music room/bar room/bar-restaurant-restaurant has has been been in in operation operation since since the the spring spring of of 2015 2015 and and hence, it was possible to conduct site measurements.measurements. Three sets of measurements were conducted:conducted: ( (a)a) ambient measurements within the music room; ( (b)b) noise reductio reductionn between the bar bar-restaurant-restaurant and the music room; and ( (c)c) Impulse response measurements within the music room. The The results results of of the three measurements are described below.

55.1..1. Acoustical Separation The acoustical acoustical separation separation between between the t bar-restauranthe bar-restaurant and the and music the music room was room established was established through throughmeasurements. measurements. Three potential Three potential noise paths noise existed paths between existed the between two spaces: the two (a) spaces through: (a) the through separating the separatingwalls; (b) through walls; (b) the through double the doors double (two doors sets); (two and sets); (c) through and (c) through the ceiling. the ceiling. Threedifferent Three different sound soundsequences sequences were played were playe throughd through the speaker the speaker system system of the bar-restaurant: of the bar-restaurant (i) 30 s: of(i)pink 30 s of noise; pink (ii) noise; 90 s (ofii)electronic 90 s of electronic music; and music; (iii) and 120 s(iii) of a120 musical s of a sequence.musical sequence. The sound The sequences sound sequences were played were at played a high at90 a to high 95 dBA 90 to level. 95 dBA The soundlevel. The sequences sound weresequences measured were at measur two locationsed at two inside locatio thens bar-restaurant inside the bar as- restaurantwell as at two as well locations as at two inside locations the music inside room. the The music average room. noise The reductionaverage noise levels reduction were calculated levels were and calculatedthe results and are presentedthe results in are Figure presented9 below. in Figure 9 below. It cancan bebe seen,seen, from from Figure Figure9 that 9 that between between ASTC ASTC (Apparent (Apparent Sound Sound Transmission Transmission Class) Class) 45 to ASTC 45 to ASTC50 noise 50 transmission noise transmission loss has been loss provided has been by provided the acoustical by the separation. acoustical The separation. northern portion The northern is seen portionto have is provided seen to have high transmissionprovided high loss transmission values compared loss values to the compared southern to portion the southern of the separation.portion of theEven separation. higher transmission Even higher losstransmission would have loss been woul obtained,d have been if notobtained, for the if following not for the reasons. following reasons.

(a) TheThe music music room room is is separated separated from from the the bar bar-restaurant-restaurant by by a a sound sound lock lock with with two two solid solid-core-core wood doors.doors. One One of of them them is is rated rated as as an an STC STC-47-47 door. door. The The second second door door is is a a simple simple solid solid-core-core wood wood door. door. TheThe STC STC-47-47 door,door, ofof thethe door-set door-set in in the the middle middle of theof the room, room, has has started started to warp. to warp. The bottomThe bottom door door seal of the second door of the same set has worn out and does not exist anymore. And Buildings 2016, 6, 11 9 of 13

Buildingsseal of2016 the, 6, second11 door of the same set has worn out and does not exist anymore. And hence,9 of 13 the leakage though the southern doors was strongly noticeable. In contrast, the northern doors were seenhence, to operate the leakage satisfactorily. though the southern doors was strongly noticeable. In contrast, the northern (b) Thedoors southern were seen portion to operate of the musicsatisfactorily. room has a large window and hence trafﬁc noise from a major (b)street The (Bloorsouthern Street) portion could of the have music interfered room has with a large the measurements, window and hence in particular traffic noise at low from frequencies a major forstreet the longer (Bloor musical Street) and could electronic have interfered sequences. with the measurements, in particular at low frequencies for the longer musical and electronic sequences.

(a)

(b)

Figure 9. Noise reduction between bar-restaurant and music room. (a) North side; (b) South side. Figure 9. Noise reduction between bar-restaurant and music room. (a) North side; (b) South side. The acoustical separation would have matched the design goal of ASTC 50, if the sound lock doorThe along acoustical the southern separation portion would performed have matched as designed. the design Finally, goal of the ASTC walls 50, and if the the sound ceiling lock were door alongobserved the southern to perform portion as per performed the design. as designed. Finally, the walls and the ceiling were observed to perform as per the design. 5.2. Ambient Sound 5.2. Ambient Sound The background levels were measured inside the music room at two locations and the results areThe shown background in Figure levels10 below. were measured inside the music room at two locations and the results are shown in Figure 10 below. Buildings 2016, 6, 11 10 of 13 Buildings 2016, 6, 11 10 of 13 Buildings 2016, 6, 11 10 of 13

90 90

80 80 South side South side

70 70 NC 70 NC 70

60 60 NC 60 NC 60

50 50 NC 50 NC 50

40 40 NC 40 NC 40

30 30 NC 30 North side NC 30

OCTAVE BAND SOUND PRESSURE LEVEL, dB re 20 micro Pa micro 20 re dB LEVEL, PRESSURE SOUND BAND OCTAVE North side

OCTAVE BAND SOUND PRESSURE LEVEL, dB re 20 micro Pa micro 20 re dB LEVEL, PRESSURE SOUND BAND OCTAVE 20 20 NC 20 NC 20 10 10 NC 10 NC 10 0 0 63 125 250 500 1000 2000 4000 8000 63 125 250 500 1000 2000 4000 8000 OCTAVE BAND CENTRE FREQUENCY, Hz OCTAVE BAND CENTRE FREQUENCY, Hz Figure 10. HVAC system sound levels inside the music room. FigureFigure 10. 10. HVACHVAC system sound levels inside the music room.room. The HVAV system was designed with silencers so that the ambient sound levels inside the music The HVAV systemsystem waswas designeddesigned withwith silencers so that the ambient sound levels inside the music room will be less than NC-35 (NC: Noise Criterion Contour). The results of Figure 10 show that along room will will be be less less than than NC NC-35-35 (NC: (NC: Noise Noise Criterion Criterion Contour). Contour). The Theresults results of Figure of Figure 10 show 10 showthat along that the northern portion, near the stage, the sound levels are less than or equal to NC-35. However, the thealong northern the northern portion, portion, near the near stage, the stage,the sound the sound levels levels are less are than less thanor equal or equal to NC to-35. NC-35. However, However, the southern portion, near the return air grille, has sound levels between NC-35 and NC-40. It was southernthe southern portion, portion, near near the the return return air air grille, grille, has has sound sound levels levels between between NC NC-35-35 and and NC NC-40.-40. It It was observed that the sound levels decreased substantially if the large return air grille was removed. And observed that that the the sound sound levels levels decreased decreased sub substantiallystantially if the if thelarge large return return air grille air grille was removed. was removed. And hence, it can be seen that the flow speed across the return air grille is high as well as the current grille hence,And hence, it can it be can seen be that seen the that flow the speed flow speed across across the return the return air grille air grilleis high is as high well as as well the ascurrent the current grille needs to be replaced with a quieter grille. needsgrille needsto be replaced to be replaced with a with quieter a quieter grille. grille. 5.3. Music Venue Acoustics 55.3..3. Music Venue Acoustics The interior acoustical performance of the music room was evaluated from impulse response The interior acou acousticalstical performance of of the music room was evaluated from impulse response measurements. The source locations and receiver locations are identified in Figure 11 below. The red measurements. The source source locations and receiver receiver locations are identified identified in Figure 11 below. The red points P1 and P2 are the two speakers located on the stage ceiling (as per our original design points P1 P1 and and P2 P2 are are the the two two speakers speakers located located on the on stage the ceiling stage (as ceiling per our (as original per our design original guidelines) design guidelines) and were used to generate sine-sweep signals. The four blue points were the receiver guidelines)and were used and to were generate used sine-sweep to generate signals. sine-sweep The four signals. blue pointsThe four were blue the points receiver were locations the receiver (1.5 m locations (1.5 meter above the floor), where the impulse responses were measured. locationsabove the (1.5 floor), meter where above the the impulse floor), responses where the were impulse measured. responses were measured.

Figure 11. Impulse response measurements locations of the empty music room. Figure 11. Impulse response measurements locations of the empty music room. Figure 11. Impulse response measurements locations of the empty music room. The impulse response measurements were analyzed using the ISO 3382 Standard procedures [7,8]. The impulse response measurements were analyzed using the ISO 3382 Standard procedures [7,8]. The results of the evaluations are presented in Table 2 below. Six acoustical parameters—Early Decay The results of the evaluations are presented in Table 2 below. Six acoustical parameters—Early Decay Time, EDT; Reverberation Time, T(30); Centre Time, Ts; Sound Pressure Level, SPL; Clarity, C80; and Time, EDT; Reverberation Time, T(30); Centre Time, Ts; Sound Pressure Level, SPL; Clarity, C80; and Buildings 2016, 6, 11 11 of 13

The impulse response measurements were analyzed using the ISO 3382 Standard procedures [7,8]. The results of the evaluations are presented in Table2 below. Six acoustical parameters—Early Decay Time, EDT; Reverberation Time, T(30); Centre Time, Ts; Sound Pressure Level, SPL; Clarity, C80; and Echo Potential, EchoDietsch are analyzed for the current case study. The various metric values at ﬁve frequency bands (250 Hz through 2000 Hz) were averaged and presented in Table2.

Table 2. Averaged acoustic response from impulse measurements.

Metrics/Locations Location 1 Location 2 Location 3 Location 4 EDT, s 0.70 0.85 0.902 0.888 T(30), s 0.90 0.85 0.85 0.91 Ts, ms 42 60 71 70 SPL, dB ´7.12 ´9.54 ´11.56 ´12.44 C80, dB 7.2 4.4 2.98 3.46 Echo Dietsch 0.40 0.44 0.46 0.47

The averaged results of the acoustic metrics were shown in Table2. The following observations can be gleaned from the results of Table2. (A) EDT and T(30) variations are not signiﬁcant and the values are well within the design goals; (B) EDT at Location 1 is low since it is closest to the source;

(C) The centre time Ts, vaues are well below 100 ms; (D) The SPL variation is not too large and hence additional rear area ampliﬁcation may be required. The above point was highlighted in our original design speciﬁcation;

(E) Clarity, C80 values are well above 0 dB and is acceptable; (F) Echo potential values are well below 0.9 and hence echo is not a concern. The main conclusion of the room acoustical measurements is that the music room performs satisfactorily and the original design guidelines have been satisﬁed adequately.

6. Comparison between Simulation and Measurements The ﬁnished music room was remodeled using a simulation software, whose results were presented in Section4. Four receiver positions were chosen with two speaker (sound source) locations, as shown in Figure 12 and the simulation were reevaluated. Sine-seep measurements were conducted in the music room, using the same sound source-receiver location combinations. The same acoustical metrics, as that of the simulation computations, were evaluated from the measured impulse responses as discussed in Section 5.3. The accuracy rating of the chosen acoustical parameters was determined by calculating the relative errors between measurements and simulations. Details of the evaluation process of the relative error can be found in Shiokawa et al. and Vorlander [15,16]. Shiokawa et al., surveyed eleven European concert halls and determined the relative errors for six acoustical parameters [15]. Vorlander’s study involved with the simulation and measurement of a 273 seat auditorium in Braunschweig, Germany [16]. Fourteen different programs were applied to simulate the auditorium and site measurements were conducted to evaluate eight acoustical parameters. Relative errors between simulation and measurement were evaluated. Simulations are deemed to be accurate if the relative errors are as close to “zero” as possible. Typical values found in the literature tend to be in the range between 2 and 10 [15,16]. Relative errors for the four acoustical metrics chosen in the current case study were evaluated from Equations (1) and (2) [15]. The relative errors for EDT and T(30) are calculated from Equation 1 below [15].

|APMeasurement ´ APSimulated| ˆ 100 AP ˆ SL ERROR “ Measurement (1) ř NPts Buildings 2016, 6, 11 12 of 13

The relative errors for Ts, and C80 are calculated from Equation (2) below.

|APMeasurement ´ APSimulated| ERROR “ SL (2) Buildings 2016, 6, 11 ř NPts 12 of 13 where, APMeasurement is the measured value of the acoustical parameter; APSimulated is the simulated valuewhere, of AP theMeasurement acoustical is the parameter; measuredSL value is the of the subjective acoustical limen parameter; of the acoustical APSimulated parameter; is the simulated and N valuePts is theof the number acoustical of measurement parameter; points.SL is the subjective limen of the acoustical parameter; and NPts is the numberThe of subjective measurement limens points. used in the evaluation of the relative errors are listed in Table3 below [ 15]. The subjective limens used in the evaluation of the relative errors are listed in Table 3 below [15]. Table 3. Subjective limens of room acoustical parameters—SL (from References [15,16]). Table 3. Subjective limens of room acoustical parameters—SL (from References [15,16]). Parameter Subjective Limen Parameter Subjective Limen EDT, s 5% EDT, s 5% T(30), s 5% T(30), s Ts, ms 10 ms 5% Ts, ms C80, dB 1 dB 10 ms C80, dB 1 dB

The results of the relative errors for the four acoustical parameters, EDT, T(30), Ts, and C80 are shownThe in results Figure of 12 the below. relative The errors results for are the shown four acoustical for ﬁve frequencies. parameters, The EDT, relative T(30), errorsTs, and are C80 well are belowshown 5.in Figure 12 below. The results are shown for five frequencies. The relative errors are well below 5.

4.5 EDT T60 Ts C80

3.5

2.5

1.5 RelativeError

0.5

-0.5 250 500 1000 2000 4000 Frequency, Hz Figure 12. RelativeRelative error as a function of frequency, units of subjective limens.limens.

Reference [15[15]] presented presented results results for for 500 500 Hz andHz and2000 2000 Hz also Hz and also the and relative the relative errors were errors between were 1between and 6. Vorlander 1 and 6. [Vorlander16] presented [16] results presented at 1000 results Hz in at his 1000 study Hz and in thehis relativestudy and errors the ranged relative between errors 0.5ranged and between 6. 0.5 and 6. It is seen therefore the current study results are in the same range as those found in the literature and the simulations areare seenseen toto produce produce realistic realistic results results that that can can be be easily easily incorporated incorporated in in the the design design of aof music a music room. room.

7.7. Conclusions Conclusions The acoustical acoustical design design of a ofproposed a proposed bar/music bar/music venue was venue compared was to compared actual ﬁeld to measurements. actual field Acousticalmeasurements. separation Acoustical between separation the two between spaces, the ambient two spaces, sound ambient in the music sound room in the and music the room acoustics and ofthe the acoustics music room of the were music evaluated room through were evaluated simulation through and the simulation results were and also the determined results were through also determined through field measurements after the facilities were constructed. The results showed that the bar/music venue perform as designed, except for two deficiencies. The deficiencies were appropriately discussed in the current study.

Acknowledgments: The authors would like to thank Jason Stein and Mathew Park of Burdock for giving permission to conduct field measurements as well as assisting during the site measurements. Acknowledgements are due Michelle Martinez, one of our students, in helping to prepare sketches. Buildings 2016, 6, 11 13 of 13

field measurements after the facilities were constructed. The results showed that the bar/music venue perform as designed, except for two deficiencies. The deficiencies were appropriately discussed in the current study.

Acknowledgments: The authors would like to thank Jason Stein and Mathew Park of Burdock for giving permission to conduct field measurements as well as assisting during the site measurements. Acknowledgements are due Michelle Martinez, one of our students, in helping to prepare sketches. Author Contributions: The first author, Ramani Ramakrishnan, contributed to the design specification of the project and evaluated separation details and background noise levels. The second author, Romain Dumoulin, simulated the music room acoustics, design goals and interior room details. The first author modelled the finished facility, conducted site measurements and prepared the manuscript. The second author evaluated the noise reduction data, prepared the subjective limen criteria and the process for calculating the relative errors of the simulation when compared with field data. Conflicts of Interest: The authors declare no conflict of interest.

References

1. Ramakrishnan, R.; Dumoulin, R. Design of a bar/music room—A case study. In Proceedings of the Acoustics Week in Canada, Halifax, 6–9 October 2015. 2. ODEON. Simulation Software for Room Acoustics; ODEON: Lyngby, Denmark, 2013. 3. Vigeant, M.C.; Celmer, R.D.; Jasinski, C.M.; Ahearn, M.J.; Schaeffler, M.J.; Giacomoni, C.B.; Wells, A.P.; Ormsbee, C.I. The effects of different test methods on the just noticeable difference of clarity index for music. J. Acoust. Soc. Am. 2015, 138, 476–491. [CrossRef][PubMed] 4. Patania, F.; Gagliano, A.; Galesi, A.; Nocera, F. Proposal to improve the acoustic quality of the main hall of Catania University. In Proceedings of the 16th International Congress on Sound and Vibration 2009, Krakow, Poland, 5–9 July 2009; pp. 1039–1047. 5. Orlowski, R. Sound strength and reverberation time in performance and rehearsal spaces for music. In Proceedings of the 2014 Forum Acusticum, Krakow, Poland, 7–12 September 2014. 6. Nocera, F.; Gagliano, A.; Evola, G.; Gioia, M.C. Acoustic quality of a tensile membrane structure used as a lecture hall, and proposals for its improvement. Build Acoust. 2014, 21, 287–304. 7. ISO 3382–1 Acoustics—Measurement of Room Acoustic Parameters—Part 1: Performance Spaces; International Standards Organization: Geneva, Switzerland, 2009. 8. ISO 3382–2 Acoustics—Measurement of Room Acoustic Parameters—Part 2: Reverberation Time in Ordinary Rooms; International Standards Organization: Geneva, Switzerland, 2008. 9. Beranek, L.L. Concert Halls and Opera Houses—How they Sound; Acoustical Society of America: New York, NY, USA, 1996. 10. Barron, M. Auditorium Acoustics and Architectural Design; Spon Press: London, UK, 2010. 11. Rossing, T.D. Acoustics in halls for music and Speech. In Springer Handbook of Acoustics; Springer: Berlin, Germany, 2007. 12. Dietsch, L.; Kraak, W. Ein Objectives Kriterium zur Erfassung von Echostrorungen bei Musik und Sprachdarbeitungen. Acoustica 1986, 60, 205–216. (In German) 13. Adelman-Larson, N.W.; Thompson, E.R.; Gade, A.C. Acoustics in rock and pop music halls. In Proceedings of the 122nd Convention of the Audio Engineering Society, Vienna, Austria, 5–8 May 2007. 14. Zeng, W.; Christensen, C.L.; Rindel, J.H. Practical methods to define scattering coefficients in a room acoustics computer model. Appl. Acoust. 2006, 67, 771–786. [CrossRef] 15. Shiokawa, H.; Rindel, J.H. Comparison between Computer Simulations of Room Acoustical Parameters and Those Measured in Concert Hall; Report #89 of the Research Institute of Industrial Technology: Nihon University, Japan, 2007. 16. Vorlander, M. International round robin on room acoustical computer simulations. In Proceedings of the 15th International Congress on Acoustics, Trondheim, Norway, 26–30 June 1995.

© 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons by Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).