ShoddyNet

Jubilee Hall

Treatments - 106m²:

• 57.6m² of 50mm absorbers covering the walls between 800-2000mm (20 panels)
• ~21m² of Heavy drape infils of spaces between rafters and ceiling (3 rafters)
• ~28m² of Heavy drape curtails at top of end walls

Reverb reduced from 3 seconds to just under 1 second. Is now a great space for large ensemble rehearsals - has enough support for instruments but manages the volume well and allows players to hear themselves and others clearly.

Should not require any more significant treatment, though might play around with diffusers over a couple of the panels to give it a little more sparkle.

Middle Hall

Treatment - 26m²:

• 11.5m² of 25mm absorbers in wooden panels with 35mm airgap (4 panels)
• 2.9m² of 50mm absorbers fixed to wall above entry door
• 7.7m² of 25mm absorbers fixed to sliding door panels
• 3.8m² of 50mm absorbers fixed to wall above sliding doors

Reverb has been cut in half from 4 seconds to around 2, with a slightly lower response when sliding doors are closed. Currently has a very nice acoustic for solo performance though is probably still a little loud for its primary users the theatre groups.

Limited space for additional absorbers (unless ceiling is utilised) but two beams could provide ideal curtain track for heavy drapes which would also create the ideal stage sized area for rehearsals.

East Hall

Treatment - 15.4m²:

• 5.8m² of 25mm absorbers in wooden panels with 35mm airgap (2 panels)
• 5.8m² of 25mm absorbers fixed to wall above serving hatch
• 3.8m² of 50mm absorbers fixed to wall above sliding doors

Reverb has been cut from 4 seconds as an empty shell to around 2.5 seconds. Prior to referbishment this hall was around 1.4 seconds and I think the stage prosenium was absorbing a lot of the sound (plus there was a large amount of theatre costumes and storage in the space)

Space for at least 4 additional framed panels (11.5m²) and additional drapes. Target for this hall should be 1.5-2 seconds to make it ideal for masterclasses, small plays etc.

Results

Reverberation times:

Space               Purpose                       Previous     Empty     Current      Target
Jubilee Hall        Large ensemble rehearsals     1.42s        3.1s      0.9s         1.0s
Middle Hall         Theatre rehearsals            2.40s        4.0s      2.0s         1.5s
East Hall           Masterclasses / theatre       1.46s        4.1s      2.4s         1.8s

Previous measurements were taken with a large number of items in each space, including some intended to manage the sound issues (carpet, drapes on walls etc). It should also be noted that each occupant of a space provides approximately 1.5m² additional absorption roughly corresponding to a 0.02s decrease in RT60 for the space based on crude estimates.

Measurements

As before measurements were made with a Beringer ECM8000, a Yamaha DBR-10 speaker and RoomEQWizard. 512k sweep from 50 to 10000Hz. The DBR-10s have a response of 55-20000Hz so ignore anything under 50Hz.

Resources

Here are the useful papers I came across while researching this.

Designing small music practice rooms for sound quality

Focused on small practice rooms but includes some tables for suggested reverberation times:

Type                    m^2     height     m^3      Reverberation time according to various standards
Ensemble /music studio  16-50   2.4-3.0    38-150   0.7-0.9    0.5-1.0     0.6-1.2    0.5-0.7      <0.6
Recital rooms           50-100  3.0-4.0    150-400  1.1-1.3    1.0-1.5     1.0-1.5     N/A         N/A
Teaching/practice room  6-10    2.4-3.0    14-30    0.7-0.9    0.3-0.6       <0.8      <0.5        <0.6