Tor Halmrast Sjefingeniør, akustiker: Musikkrom
STORE ROM EN-BRUK Bach skrev musikk for samme kirke i 16 år I dag: FLERBRUK «Skal brukes til alt- Kan ikke brukes til noenting» Byggherre Akustikk/Teater/Forestillings-kompetanse? «The Importance of beeing early» Kompetanse inn FØR arkitekt etc.
Romprogram: B x L x H Prioriteringsliste, etter Etterklangsforhold, ikke slik: 3) Konferanse 6) Kor 1) Rock 2) Kino 5) Filharmonien på turné (1x pr. 24 år)
Angi Form og Volum allerede FØR arkitektkonkurranse Stavanger Konserthus Oslo Opera
Oslo Konserthus: Trekantformet Tomt Trekantformet Sal!!!
Form= innhold? PS! En tilsynelatende «musikalsk» form er ikke alltid egentlig god akustisk. NRK Store Studio er «feil vei»
Hvis man lover alt blir ingen fornøyde Hvis man derimot lover f.eks: - God til Kor, kanskje jazz-trio, blir mange fornøyde når det også fungerer noenlunde for «snill pop».
IKKE BLI BLENDET AV AT OPERAEN KLARER «ALT» Motorpsycho + blås + strykere i Operaen Berlin Philh. i Operaen Operaen er et UNNTAK «Ikke prøv dette (i samme) rom hjemme!!!»
Vanlige skoler etc. kan ikke rigge provisoriske scener når det skal skje musikk-aktivitet
GYM-SALER har faktisk OK romform, men feil veggkledninger/reflektorer etc. Alle mål er på idrettens definerte premisser!
SMÅ ROM App. 11 i høringsutkastet til standarden, finnes på Akutek: «Musician s Perceived Timbre and Strength in (too) small rooms» http://www.akutek.info/papers/th_smallrooms_timbre_strength.pdf
L=4.33m, W=2.14m, H=2.28m ca 22 m3 Forsvarets Musikk Korps, Nord Norge Kulturhuset, Harstad
Corner/ «Bass»- Absorber 4 Wall-Absorbers, 10 cm Cosmos
Reverberation Times Tm: Nothing: 0.5 Curtain: 0.42 Non-Dampened Curtain+Corner: 0.33 All: 0.27 Dampened
Musician s Perceived Reverberation Dampened Non-Dampened just curtains Schroeder curves for In-Ear measurements of own tongue drops.
Non-Dampened room, just curtains Dampened room Reverberation times for In-Ear measurements of own tongue drops. (User defined T15, taken from -20 db to -35 db). PERCEIVED greater reduction than standardised MEASUREMENTS
Mid-frequencies (315-2000 Hz) Reduction of sound pressure levels: STANDARDISED MEASUREMENTS WITH LOUDSPEAKER Curtain: 1.5 db Curtain + Corner: 3.0 db Curtain + Corner + Wall: 6.5 db so that the change between Curtains Only ( Non-Dampened ) and All Absorbers ( Dampened ) is 5 db.
Measured In Room
Conclusion, Sound Pressure Level MUSICIAN as SOURCE: Measured reduction in sound pressure level at the musician s ear when introducing the extra absorbers is 1-2 db less than the reduction measured with a constant loudspeaker source. Musicians compensate for the reduced answer from the room.
COMPARISONS with CALCULATIONS - Lp from Lw values from literature (Meyer) - Lp Measured Instrument ppp pp p-mf f ff fff Clarinet 55 75 93 117 Trumpet 77 89 101 103 111 Trombone 73 88 101 104 113 Tuba 77 93 106 108 112 T=0,5 s TUBA f NS/Rindel 103.2-103.6 Måling (102)
NS/Rindel 103.2-103.6 Måling (102)
(non-calibrated) TRUMPET LAeqT LCpeak Sone Phon max Whole Piece Dampened 88.4 108.5 Un-Dampened 89.9 105.2 10 s forte, f Intro Dampened 71.8 101.7 Un-Dampened 90.2 105.0
Perceived In-Ear changes in Strength (G) Non- Dampened Dampened 3-5 db reduction of Perceived G when introducing all absorbers
Timbre In-Ear -measurements, clarinet Dampened Non-Dampened
TUBA
Whole Composition TRUMPET Dampened Non-Dampened
CLARINET Spectrum Slice 10 sec High C repetitions ~ 1000 Hz Linear freq. axis
Peak spectral centroid 10 s section Dampened: 3617 Hz Non Dampened: 3930 Hz
Non-Dampened Room: Unpleasant sharpness for 2-4 khz Frequency region where the human ear is most sensitive Possibility of hearing loss?
SONE/BARK Trombone Bark region 7-12: 700-1600 Hz Facing MIRROR Facing CURTAIN
ROOM RESONANCES «by ear»
1:1:0 90.0 Hz corner 0:2:1 109.2 Hz corner ceiling 1:0:1 110.5 Hz corner ceiling 1:2:0 114.2 Hz Corner!! 1:1:1 117.6 Hz (corner) (ceiling) 0:3:0 119.7 Hz Corner!! 136 Hz
ROOM RESONANCES Non-dampened w/corner ABSORBER Rest: Resonance Ceiling/Floor (In practice: dampened by musician)
Schroeder-Curve 125 Hz 1/1 oct Non-dampened: Resonances, Double/triple slopes w/corner ABSORBER:
Dampened Non- Dampened
CONCLUSION Dampened Room-Non Dampened (only curtain) Reduction db: LOUDSPEAKER MEASUREMENTS: 3-5 db MUSICIANS COMPENSATE: 1-2 db less
The main effect of a well absorbed room in practice is to: 1)Reduce «SHIMMERING» of high frequencies 2)Dampen (some) room (bass)-resonances These issues are more important than a common reverberation time approach when designing (too) small rooms for music