Tor Halmrast Sjefingeniør, akustiker: Musikkrom

Transkript

1 Tor Halmrast Sjefingeniør, akustiker: Musikkrom

2 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.

3 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)

4 Angi Form og Volum allerede FØR arkitektkonkurranse Stavanger Konserthus Oslo Opera

5 Oslo Konserthus: Trekantformet Tomt Trekantformet Sal!!!

6 Form= innhold? PS! En tilsynelatende «musikalsk» form er ikke alltid egentlig god akustisk. NRK Store Studio er «feil vei»

7 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».

8 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!!!»

9 Vanlige skoler etc. kan ikke rigge provisoriske scener når det skal skje musikk-aktivitet

10 GYM-SALER har faktisk OK romform, men feil veggkledninger/reflektorer etc. Alle mål er på idrettens definerte premisser!

11 SMÅ ROM App. 11 i høringsutkastet til standarden, finnes på Akutek: «Musician s Perceived Timbre and Strength in (too) small rooms»

12 L=4.33m, W=2.14m, H=2.28m ca 22 m3 Forsvarets Musikk Korps, Nord Norge Kulturhuset, Harstad

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15 Corner/ «Bass»- Absorber 4 Wall-Absorbers, 10 cm Cosmos

16 Reverberation Times Tm: Nothing: 0.5 Curtain: 0.42 Non-Dampened Curtain+Corner: 0.33 All: 0.27 Dampened

17 Musician s Perceived Reverberation Dampened Non-Dampened just curtains Schroeder curves for In-Ear measurements of own tongue drops.

18 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

19 Mid-frequencies ( 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.

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21 Measured In Room

22 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.

23 COMPARISONS with CALCULATIONS - Lp from Lw values from literature (Meyer) - Lp Measured Instrument ppp pp p-mf f ff fff Clarinet Trumpet Trombone Tuba T=0,5 s TUBA f NS/Rindel Måling (102)

24 NS/Rindel Måling (102)

25 (non-calibrated) TRUMPET LAeqT LCpeak Sone Phon max Whole Piece Dampened Un-Dampened s forte, f Intro Dampened Un-Dampened

26 Perceived In-Ear changes in Strength (G) Non- Dampened Dampened 3-5 db reduction of Perceived G when introducing all absorbers

27 Timbre In-Ear -measurements, clarinet Dampened Non-Dampened

28 TUBA

29 Whole Composition TRUMPET Dampened Non-Dampened

30 CLARINET Spectrum Slice 10 sec High C repetitions ~ 1000 Hz Linear freq. axis

31 Peak spectral centroid 10 s section Dampened: 3617 Hz Non Dampened: 3930 Hz

32 Non-Dampened Room: Unpleasant sharpness for 2-4 khz Frequency region where the human ear is most sensitive Possibility of hearing loss?

33 SONE/BARK Trombone Bark region 7-12: Hz Facing MIRROR Facing CURTAIN

34 ROOM RESONANCES «by ear»

35 1:1: Hz corner 0:2: Hz corner ceiling 1:0: Hz corner ceiling 1:2: Hz Corner!! 1:1: Hz (corner) (ceiling) 0:3: Hz Corner!! 136 Hz

36 ROOM RESONANCES Non-dampened w/corner ABSORBER Rest: Resonance Ceiling/Floor (In practice: dampened by musician)

37 Schroeder-Curve 125 Hz 1/1 oct Non-dampened: Resonances, Double/triple slopes w/corner ABSORBER:

38 Dampened Non- Dampened

39 CONCLUSION Dampened Room-Non Dampened (only curtain) Reduction db: LOUDSPEAKER MEASUREMENTS: 3-5 db MUSICIANS COMPENSATE: 1-2 db less

40 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