Reverberation room A3-006.
Measurement concerning fullfillment standard related to reverberation rooms. Our room now contains a Low Frequency Chamber (LFC) which have been used for Low frequency experiments with humans. Due to this the room volume have been decreased and the shape have changed. Measurements have been made to check if the room still fulfills iso354/3741/3742 and can be used eg. for classification of absorbtionpanels (iso 11654 / iso354) or for declaration of noiseemmison from eg. ITequipment (iso 9296 / iso 7779). The last part with can be difficult due to relatively high (~35dbA) background noise level (ventilation, toilets, people in buildning) during normal daytime.
Department of Electronic Systems Acoustics Fredrik Bajers Vej 7 BAalborg phone: fax: mail: acoustic@aco.es.aau.dk web: acoustics.es.aau.dk
Volumen of our room is now 199m3, and this means that the physical demand which we have trouble fullfilling is the demand in iso354 of lmax < 1.9 x V 1/3 and a volumen of minimum 200m3 for measurements down to 100Hz (1/3octave band). Our room have and lmax of 11.2m which is a little more than the demand set in above formula which gives a value of 11.1m. This minor detail will be fixed later on. Number of diffusers have been decreased from 7 to 5 after the LFC have been constructed. This have been tested with succes according to iso354/annex A.2. Measurements have been carried out with mainly abrupted pink-noise, since it's the easiest way to obtain a good (>40dB in all freq.bands) signal to noise ratio. However to see how results obtained with this method a number of measurements have also been carried out with integrated impulse-response method. Furthermore the first of these methods are also considerably faster due to the posibility of using our 4channel Harmonie measuring system (4channels, all freq.bands simultaneously in about 15secs) compared with B&K2231+BZ7109 (1channel, 1 freq.band in 30-10secs depending on frequency). In the following figures and tables it can be seen to which extend the room can be used if standard iso354/3741/3742 should be fullfilled. Picture shows actual setup used during this measurement session.
Table 1 - shows an overview of data obtained in the reverberation room.
Frequency Hz 1k 1.25 k 1.6 k 2k 2.5 k 3.15 k 4k 5k 6.3 k 8k 10 k m*m 2,8 2,9 3,3 3,2 3,3 3,4 3,7 4,1 4,3 4,8 6,2 7,0 6,9 7,3 8,5 9,9 11,4 13,9 17,5 22,8 30,8 Measured data absorp.area Rt *** sec. 11,29 10,89 9,74 9,99 9,84 9,42 8,58 7,84 7,43 6,64 5,16 4,59 4,65 4,37 3,76 3,22 2,81 2,31 1,83 1,41 1,04 ISO354 average diff. mean max absorp s % m*m 0,01 -4% 6,5 0,01 -1% 6,5 0,01 2% 6,5 0,01 0% 6,5 0,01 0% 6,5 0,01 -1% 6,5 0,02 0% 6,5 0,02 0% 6,5 0,02 -1% 6,6 0,02 -2% 6,8 0,03 1% 7,0 0,03 2% 7,8 0,03 -1% 8,6 0,03 -1% 9,5 0,04 0% 10,6 0,04 0% 11,8 0,05 -1% 13,0 0,06 -1% 14,1 0,08 -1% 15,3 0,10 -1% 16,4 0,13 36% 17,6 fulfilled? yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes no no no Rt min sec 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 0,87 ISO3741/42 s max fulfilled? 0,16 0,16 0,16 0,16 0,16 0,16 0,06 0,06 0,06 0,06 0,06 0,06 0,06 0,06 0,06 0,06 0,06 0,06 0,06 0,06 0,06 yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes no no no
*** Measured Rt (average of 60 measurements) is used for calculating Absorption area from Sabin's formula.
note that iso 354 are not fullfilled for physical dimensions (se previous page)!! Table 2 - shows diffences between abrupted pink noise and integrated impulse methods

Frequency Hz 1k 1.25 k 1.6 k 2k 2.5 k 3.15 k 4k 5k 6.3 k 8k 10 k Measured data dBati32 absorp.area Rt *** std.dev m*m sec. 2,8 11,29 1,13 2,9 10,89 1,09 3,3 9,74 1,16 3,2 9,99 0,54 3,3 9,84 0,56 3,4 9,42 0,40 3,7 8,58 0,32 4,1 7,84 0,20 4,3 7,43 0,21 4,8 6,64 0,18 6,2 5,16 0,15 7,0 4,59 0,10 6,9 4,65 0,09 7,3 4,37 0,08 8,5 3,76 0,05 9,9 3,22 0,05 11,4 2,81 0,04 13,9 2,31 0,03 17,5 1,83 0,03 22,8 1,41 0,02 30,8 1,04 0,02 Measured data B&K2231 absorp.area Rt** st.dev m*m sec 3,0 10,66 1,26 3,1 10,42 1,17 3,5 9,21 1,06 3,4 9,54 0,60 3,3 9,58 0,73 3,5 9,23 0,51 3,8 8,37 0,32 4,2 7,71 0,18 4,3 7,43 0,20 4,7 6,77 0,21 6,1 5,21 0,15 7,0 4,60 0,08 6,9 4,67 0,08 7,3 4,37 0,12 8,7 3,69 0,09 9,9 3,23 0,04 11,3 2,83 0,04 13,9 2,30 0,04 17,6 1,82 0,03 22,8 1,41 0,02 31,5 1,02 0,01
** Measured Rt bk2231 (average 12 measurements/decays) used for calculating Absorption area from Sabin's formula *** Measured Rt dBati32 (average of 60 measurements/decays) is used for calculating Absorption area from Sabin's formula.
Table 3 - shows diffences between std.mic.pos and random selected mic.positions.
Frequency Hz 1k 1.25 k 1.6 k 2k 2.5 k 3.15 k 4k 5k 6.3 k 8k 10 k Measured Rt data dBati32 ** Standard mic. positions random H1 H2 H4 H1 sec. sec. sec. sec. 11,73 11,17 11,14 11,66 11,85 11,65 10,91 10,78 9,17 10,08 8,83 8,90 9,87 9,67 9,56 10,03 9,85 9,61 9,97 9,69 9,73 9,64 9,80 9,90 8,79 8,55 8,65 8,69 7,76 7,90 7,76 7,86 7,35 7,31 7,32 7,37 6,63 6,62 6,61 6,61 5,16 5,20 5,17 5,20 4,59 4,61 4,62 4,60 4,57 4,65 4,60 4,67 4,31 4,30 4,33 4,36 3,71 3,72 3,72 3,73 3,17 3,20 3,17 3,15 2,75 2,74 2,76 2,76 2,25 2,25 2,23 2,27 1,79 1,79 1,79 1,79 1,35 1,37 1,34 1,37 1,00 1,01 0,99 1,00 mic. positions H2 H4 sec. sec. 11,11 10,81 11,24 11,26 10,32 8,86 9,92 10,25 9,69 9,97 9,72 9,73 8,74 8,91 7,94 7,88 7,39 7,29 6,68 6,70 5,21 5,17 4,57 4,65 4,65 4,63 4,31 4,34 3,74 3,74 3,14 3,20 2,78 2,75 2,26 2,25 1,80 1,78 1,37 1,37 1,01 1,00
** Each value for Rt is calculated as average of 4 mic.positions 3 repetions table shows for 3 different speaker-positions as seen at 160Hz loudspeaker position have some influence on measured values.
Figure 1 sketch showing room with std.mic.& speaker positions and diffusors.

M1 M3 M4 LFC H4

Measurements done by: Claus Vestergaard Skipper Document updated: 19. september 2006 Equipment used during these measurements: B&K 2231 SLM aauno.8236 + BZ7109 Reverberation Module 01dB Harmonie system (pc with DAQ-unit) 56524 & 60923 Microphones: 2x B&K4134 aauno 8129 & 8130, 2x B&K4166 aauno 8601 & 8602 Microphone preamps: GRAS 26AK aauno 52664, 52665, 56525 & 56526 Microphone powersupply: 2x B&K 2804 aauno 6998 & 7304 Loudspeaker: EV-S200 aauno. 8722- eq present setting PowerAmplifier: Pioneer A-616 aauno. 8249 - fixed gain 20dB setting Measurements in reverberation room have been done in the periode from 31.juli 2006 14.september 2006 ,. Figure 2 measurement setup.

FOR IMMEDIATE RELEASE
Pioneer Construction Named No. 1 "Green Contractor" in West Michigan, Top 100 in Nation, by Engineering News Record Magazine
GRAND RAPIDS, Mich., September 16, 2009 Pioneer Construction, one of the largest full service contracting and construction employers in West Michigan, today announced that it has been named the number one Green Contractor in West Michigan and ranked 75th in the United States by Engineering News-Record (ENR), a prominent magazine tracking the construction industry. Pioneers rank on ENR's overall green building list represents the highest ranking for any West Michigan based firm, and the second-highest ranking in Michigan. The rankings are based on construction and contracting revenue from registered or certified sustainable projects. Engineering News Record is the leading magazine covering the construction industry. "We are proud to be number one in West Michigan, and noted as one of the nations top green contractors. Pioneer has a cultural commitment to sustainable practices, and our focus is on helping our customers develop buildings that perform in every way. said Tim Schowalter, president of Pioneer Construction. "Our buildings must provide quantifiable returns for the owners this includes incorporation of sustainable building principles that provide demonstrable life-cycle cost savings. Our sustainable construction methods and existing LEED projects are prime examples of Pioneers attention to the needs of our clients, their bottom lines, and our community." This is the second consecutive year that Pioneer has been ranked by ENR as the top green contractor for West Michigan and among the top 100 in the country. LEED, or Leadership in Energy and Environmental Design, is a system designed by the U.S. Green Building Council to certify and rate facilities on conservation, energy reduction and sustainability. This year's Top 100 Green Contractors generated $38.69 billion in 2008 from projects that either were registered or certified with a major third-party environmental standards or ratings group, a 69.9% increase from last year. There are three Michigan firms on the Green Contractors list. About Pioneer Construction Founded in 1933, Pioneer Construction is one of the largest full service general contracting, designbuild, and construction management companies in Michigan offering a full range of services. Headquartered in Grand Rapids, Mich., Pioneer emphasizes the companys commitment to build on the values, quality, and service that define its seventy-six year history with the vision and innovation of a new generation. The Company strives to bring unparalleled value to customers through delivering high quality construction projects, while also maintaining an active dedication to the promotion of sustainable design and construction practices. To find out more about Pioneer Construction, please visit www.pioneerinc.com.
Contacts: Chris Beckering Pioneer Construction (616) 247-6966 chris@pioneerinc.com
David Buckalew Lambert, Edwards & Associates (616) 233-0500 dbuckalew@lambert-edwards.com