Large-Array Subwoofer
Listening Workshop
7:30pm, Monday, January 29,
2001
Paramount Theatre, Seattle,
WA.
A) To observe how the same number and type of subwoofers behave differently when configured in different arrays, and the effect of quantity on performance.
B) Observe other methods of generating very low frequencies while maintaining pattern control.
C) Provide an opportunity for analysis hobbyists using SMAART, Spectrafoo, Mac the Scope, etc., to examine large arrays of subwoofers.
Discussion on the live-audio Bulletin Board which gave impetus to this event can be found at:
http://www.live-audio.com/messages/52785.html
http://www.live-audio.com/messages/52804.html
and concerning the effects of Very Low Frequencies on hearing loss at:
http://www.live-audio.com/messages/archive2/39541.html
http://www.live-audio.com/messages/archive2/38774.html
Descriptions of previous events by the same sponsors and coordinators can be found at
http://www.aes.org/sections/pnw/pnwrecaps/1998/subs/subs.html
http://www.aes.org/sections/pnw/pnwrecaps/1997/loudspeakers/speakers.html
Note: (affiliations for identification purposes only, as known; listing here in no way implies approval of this protocol or anything else.):
Barry Bozeman (Seismic Systems and Live-Audio Board participant)
Christopher Whitt (Live-Audio Board participant)
Curt Hare (Point Source, Inc.)
Daniel Casado (First Choice Marketing)
David Tosti-Lane (Cornish Institute for the Arts)
Dennis Griffiths (Audio Control)
Henry Heine (Bag End)
Josh Millward (Live-Audio Board participant)
Patrick Scott (Live-Audio Board participant)
Paul Bauman (l'Acoustics, France)
Rick Smargiassi (PNW AES Chair/ Integrated Light & Sound)
David Lee (Rhino Sound and Live-Audio Board participant)
Scott Holden (McCauley)
Tom Danley (Servodrive, Inc. and Live-Audio Board participant)
Weogo Reed (Live-Audio Board participant)
William Cowan ((Live-Audio Board participant)
Attendance will be open to any interested persons. There will be no cost to attend.
The theatre is a classic vaudeville-style proscenium theatre, with a seating capacity of just under 3000. It has a balcony, which will be closed for this event. All listening will be done on the main orchestra level, which measures roughly 120' deep by 120' wide. The theatre was built in the early 1900's, and was significantly remodeled in the mid 1990's. It has a unique movable floor, which can be configured several ways: a traditional sloped floor with fixed padded seats; a flat floor at orchestra level with portable or no seating; or a flat floor at stage level with portable or no seating. Our preference will be to use the traditional sloped floor with fixed padded seats, but, realistically, we will be at the mercy of whatever configuration is used before and after our event. Should it be in flat-floor configuration, there will be a 9' or so hard wall at the rear of the theater. It should be noted that the movable floor is accomplished via numerous adjustable jacks underneath the floor; this means there is a lightweight floor above a large empty concrete cavity, thus significantly increasing the volume of the room at low frequencies. The schedule as of 1/10/01 indicates that the floor will be in sloped mode, with fixed padded seats.
The theatre is used for all kinds of theatrical and musical events on a daily basis, and is widely admired for its acoustics and suitability for live events.
A) Carlson Audio will provide 16 x EAW SB-1000 dual 18" subwoofers, and NAF Productions will provide 16 x EAW SB-1000 dual 18" subwoofers, for a total of 32. Carlson Audio will provide all amps, crossovers, cabling, power distro, trucking, and rigging, except as outlined below.
1) Servodrive Inc. will provide 12 BT-7 hornloaded subwoofers, with 3 Crown MA-3600 amps to drive them, all cable between amps and speakers, and the AC distro for those amps. 2) Rhino Sound will provide 4 to 6 BassMaxx hornloaded subwoofers, with amps.
B) Load in to Paramount Theatre will be at 10:00am on Jan. 29. The public event will begin at 7:30pm. Doors will open at 7:00pm. There will be a dinner break from 5:30pm to 7:00pm, with a no-host dinner for participants at a nearby restaurant. Refreshments at the event will be provided by the PNW AES.
C) After load-in, verify functioning and correct polarity of each driver by first verifying one box, then placing each box adjacent to verified box, connecting in parallel, and listen to one driver at a time. Repeat for all boxes. (Functioning of amps and cables will be previously verified.)
D) Mid/hi listening will be accomplished by lowering the Paramount's center cluster of 2 x Meyer MSL-4's and 2 x Meyer CQ-2's.
E) The EAW subwoofers will be arrayed onstage in two clusters, equidistant from the centerline of the stage, except as noted below. 1) The Servodrive speakers will be arrayed adjacent to the proscenium, either left or right, or as determined by the Event Coordinators.
1) The BassMaxx speakers will be arrayed adjacent to the proscenium, either left or right, or as determined by the Event Coordinators.
F) For comparison purposes, a crossover input signal level will be established which will remain constant throughout the testing. The input signal to the crossover will be electrically monitored by a device with a readout large enough that multiple people can verify signal level.
G) During the testing, attendees will be encouraged to roam the theater to hear the effects of subjective angle and distance on array performance. Distance and angularity markers will be placed throughout the listening area, so attendees can locate themselves relative to the arrays. In addition, there will be light fabric pieces placed throughout the auditorium (probably on mic stands) so that air movement can (maybe) be observed.
H) AudioControl will place a reference mic on the face of the balcony, connected to an SPL meter with a very large, very bright readout located onstage beneath the center speaker cluster. The meter will be calibrated to read ***unweighted*** dbSPL. Additionally, there will be SPL meters located throughout the theater, some reading dbA and some reading db(unweighted). Mics to meters reading dbA will be located adjacent to those reading db(unweighted), so attendees can see the relationship of dbA to dbUnweighted.
I) Attendees and participants will be encouraged to bring their own analysis systems, and provision will be made for placement throughout the listening area, meaning a flat surface, an AC connection, and to the best of the organizersĖ abilities, an isolated dry signal from the main source mixer. Attendees will be encouraged to discuss measurements with analysis system providers, but such discussions (and verification of analysis functioning) will not be allowed to take up event time, unless there is a clear issue of interest to the group (as decided by the event coordinator).
J) To assist attendees in seeing air movement, some form of very lightweight ribbons or similar non-noise-making material will be placed in front of each speaker (and throughout the theater, as noted in G) above), so that air movement in each part of the array can be observed independently. This material will be provided by PNTA.
K) Source material will be the same as used for the January 1998 Large Array Subwoofer Listening Workshop presented by the same lead sponsors. Choices are as follows (Title/Artist- CD Title/Source or CD #):
1) Pink noise/generator/Synaudcon Test CD
2) Sweep up 5-300hz/Function Generator
3) Sweep down 300-5hz/Function Generator
4) Shaped Sine bursts 250-20hz/Don Keele/Synaudcon Test CD
5) Kick Drum/Wendell Jr./Masterfonics Studio Test Disc
6) Kick & Snare/Wendell Jr./Masterfonics Studio Test Disc
7) Bass Guitar/Alan Parsons Sound Check/MSFL SPCD 15
8) Big Bass/Sampler/Prosonus Sampler Sampler
9) Bass & Drum mix/ Thomas Dolby/ Lexicon Demo CD
10) Big Bass Drum/ Barbra Streisand- How Does the Wine Taste?/People/Columbia ck9015
11) Drum Kit/ Ron Tutt/Sheffield Drum Record cd-14 20
12) Deep Note/ Jeffrey Borish/ Lucasfilm Electra 9 60303-2
13) Train Wreck/ The Fugitive Soundtrack/ Laserdisc
14) Canal Chase/ Terminator 3 Soundtrack/ Laserdisc
15) Attention!/ Tocata & Fugue in D Minor/ Wilson wcd-8111
16) Higher You Rise/ Robbie Buchanan, James Newton Howard & Friends/Sheffield cd-14 20
17) Metro/ Greg Adams- Hidden Agenda/ Epic dk 66768
18) Airhead/ Thomas Dolby- Aliens Ate My Buick/ EMI cdp-7-48075-2
19) Speak to Me/ Pink Floyd- Dark Side of the Moon / EMI 7-81479 2 3
20) Another Brick in the Wall/ Pink Floyd- The Wall/ MFSL UFCD 2-537
21) Also Sprach Zarathustra/ Seattle Symphony/ Delos Sampler
22) Carillon de Westminster/ Virgil Fox- Plays the John Wanamaker Organ/ Bainbridge bcd2501
23) Little Bird/ Annie Lennox- Diva/ Arista 18704-2
24) The Facts About Jimmy/ Shawn Colvin- A Few Small Repairs/Columbia ck 67119
25) Watermark/ Enya- Watermark/ Geffen 24233-2
26) The Long Ships/ Enya- Watermark/ Geffen 24233-2
27) A Day in Tunisia/ Spies- By Way of the World/ Telarc cd-83305
28) This Time/ Dwight Yoakum- Inside the Pocket of a Clown/ Reprise 452541-2
29) Tocata & Fugue in D Minor/ James Welch- Magnum Opus/Wilson wcd-8111
30) SerpentĖs Tongue/ Dead Can Dance- The SerpentĖs Egg/Warner 45576-2
31) Finest Work Song/ REM- Eponymous/ IRS IRSD-6262
32) Busy/ Crystal Method- Vegas/ City of Angels OPRD30003
33) Bassgasm/ Techmaster PEB- Bass Computer/ NewTown NTN2008
34) Use Me/ Junior Wells- Everybody's Getting Some/Telarc CD-83360
35) The Hunter/ Jennifer Warnes- The Hunter/ PrivateMusic 01005-82089-2
36) Sleep to Dream/ Fiona Apple- Tidal/ Clean Slate OK67439
37) Walkin in the Same Tracks/ Terry Evans- Puttin It Down/ Audioquest AQ CD1038
L) Each array to be examined will consist of 16 x EAW SB 1000. When possible, arrays will be instantaneously A-B'd to compare various aspects of performance. Those aspects include:
1) Directivity, both horizontal and vertical
2) Evenness of frequency response
3) SPL differences (efficiency)
4) Others?
M) Array types to be examined:
1) Vertical line array, sitting on stage (8 boxes tall)
2) Vertical line array, sitting on orchestra floor (8 boxes tall)
3) Vertical line array, suspended in air at various heights (suspended portion will be limited to 8 boxes for safety reasons)
4) Horizontal line array, sitting on stage, spanning width of auditorium
5) Square block (4 boxes x 4 boxes)
6) Rectangular block, wider than it is tall (8 boxes by 2 boxes)
7) If possible, rectangular shape, one box thick going up each proscenium wall, across the orchestra floor from proscenium wall to proscenium wall, and in the air from proscenium wall to proscenium wall
8) Others?
N) Because the direct-radiator and horn-loaded systems do not lend themselves to A-B comparison (in terms of comparing apples-to-apples), there will be a separate 20 minute time period allocated to each company to demonstrate their product.
O) Source material will be played through a decent-quality CD player and routed through The Paramount's Yamaha PM-4000 mixing console. Low-pass filtering and muting will be done by a BSS FDS-366 Omnidrive Compact.
P) ALL ARRAYS ARE SUBJECT TO SAFETY CONSIDERATIONS; EVENT COORDINATORS AND PARAMOUNT STAFF MAY ELIMINATE OR REDUCE THE SIZE OF SOME ARRAYS IF THEY HAVE ANY CONCERNS ABOUT SAFETY TO PARTICIPANTS OR AUDIENCE.
Q) All rigging before the event, and equipment moving during the event, will be done by Paramount stage crew, hired at their normal rate. There will be a Paramount usher at the entry door from 6pm until 11pm. Crew and facility charges will be paid for by the PNW AES.
Written by Dan Mortensen
dansound@att.net
(206) 525-2113