06 April 2006

Noise measurements inside the Coliseum

The measurements made last night will provide a baseline for measurements I'll make outside the Coliseum, China Basin, and other ballparks. The decibel (dB) scale is logarithmic like the Richter scale, so 70 dB can be interpreted as twice as loud as 60 dB. (There's a good primer on sound and noise propagation at Last night I measured crowd noise in the bowl at three different points: Section 137 of the LF bleachers, the concourse behind Section 107, and the 4th row of Section 203. I don't have a very sophisticated sound level meter that has real time logging or analysis capabilities, so take these measurements with a decent margin of error (± 3 dB) and several grains of salt. I used "A-weighting" for the measurements.
The ambient crowd noise in the seating bowl was in the 70-75 dB range when the crowd was idle. Drums and chants brought the noise up 5-8 dB. Between innings, the PA caused the range to be 75-82 dB. Compare that to the interior of a BART train (60 dB stopped/71 dB moving).

Readings from the bleachers (first three innings):
  • Giambi intro/BALCO chant: 92 dB
  • Giambi groundout to 1B: 99 dB
  • Matsui HR to RF: 96 dB spike, 92 dB roar
  • "Let Go ___" chant: 90 dB
  • First 2-2 pitch to Sheffield: 90 dB
  • Sheffield HR: 95 dB
Concourse behind 107, where a group of shrill young girls (A's fans) were chanting back-and-forth with another group of slightly less shrill young boys (Yankees fans).
  • Jeter drop/error: 101 dB
  • Bradley single, 2 RBI: 104 dB
  • Payton single: 104 dB
  • "Let's Go Oakland" chant: 96 dB
  • Kendall beats out DP: 102 dB
  • Bradley walks, scoring Ellis: 107 dB
  • "Yankees Suck" chant: 95 dB
  • Waiting in line for dollar dogs: 82-84 dB

Section 203. After the Scutaro single, many Yankees fans departed. The Thomas double begat a mass exodus. The readings:

  • Damon grounds out to Duke: 92 dB
  • "Take me out to the ballgame": 82 dB throughout, 88 dB climax
  • A-Rod K's: 94 dB
  • Giambi intro: 83 dB
  • Giambi flies out: 93 dB
  • Sharks highlight on DiamondVision: 91 dB
  • Bradley triple: 99 dB
  • Cano error, Payton safe: 104 dB
  • Kendall single: 98 dB
  • Scutaro RBI single: 101 dB
  • Thomas double, 2 RBI: 101 dB

Other readings taken elsewhere in the stadium:

  • Concourse behind the bleachers: 82 dB
  • Section 103 aisle during Dot Racing climax: 95 dB (proving that Dot Racing isn't the most cheered event at A's games)
  • BART bridge almost underneath southbound tracks before the game: 88 dB
  • BART bridge before game, middle: 75 dB
  • Standing platform in RF near flags, end of game: 89 dB
  • BART bridge after game near saxophone player but not while he's playing: 67 dB
  • When the sax guy is playing (I really should ask him to play "Take the A Train" more often): 77 dB
It's important to note that very few of these "events" lasted for more than 2-3 seconds. There was a slight trickle of people leaving as early as 9:00 p.m. Roughly half the crowd was left at the end.

I'll make the next measurements in the Giants-Astros series next week, on the promenade outside the ballpark and McCovey Point (the little park across Mission Creek from the stadium). These will be important because unlike the current Coliseum, China Basin is an open design that doesn't trap or absorb noise as well as the Coliseum.

Attendance Analysis, Part I

Update: This post just got a mention in the SFGate "A's Drumbeat" blog. Sweet!

Now that the first three games are in the books, it's time to do a comparison between the new, smaller Coliseum and last year's larger model. Having the Yankees series at the beginning of the year creates a disadvantage for the A's because Opening Day usually brings in 40,000+, so to have a Yankees game on Opening Day effectively eliminates one potentially high attendance date from the schedule. The Coliseum's stated capacity this year is 34,077 plus 1,000 or so standing room admissions. Last year the capacity was 48,219.

First, let's look at the first series this year vs. the first series last year:

  • 2006 (vs. NYY): 35,077 / 31,284 / 30,165. Total: 96,526. Average: 32,175 (94.4% of capacity)
  • 2005 (vs. TOR): 44,815 / 10,106 / 15,860. Total: 70,781. Average: 23,594 (48.9% of capacity)
The drop-off in 2005, as noted by local media at the time, was precipitous to say the least. A small dropoff has occurred this year, though it really amounts to 6-7%. That should at least get the press off the A's backs for now. The next homestand against Texas and Detroit will paint a more realistic picture. Since the first series was against the Yankees, let's look at how May 2005's Yankees series stacks up against the last three days:

  • 2006 (vs. NYY): 35,077 / 31,284 / 30,165. Total: 96,526. Average: 32,175 (94.4% of capacity)
  • 2005 (vs. NYY): 38,636 / 41,180 / 37,237. Total: 117,053. Average: 39,018 (80.9% of capacity)
This puts the A's over 8,000 ahead of last year's pace but almost 7,000 behind last season's Yankees series. Those that decried the third deck closure referred to reduced capacity as reduced revenue opportunity. However, the new pricing tier structure appears to be meant to establish two things: a greater amount of revenue per ticket sold, and a less elastic demand curve for A's tickets. The first goal will be reached by default simply through the removal of 10,000 $9 seats per game, many of which turned into $1 seats on Wednesdays. There's too small a sample size at this point to know if the second goal has been reached, but I would expect that the last year's game-over-game standard deviation, 10,511, could be cut in half with these changes.

I didn't attend Tuesday's game, but Wednesday's game showed how effective the structure has been so far. Most of the empty seats were in the furthest reaches of the Plaza and Field levels, along with hundreds of Plaza Bleacher seats. That's exactly what the team wants on a regular basis. The removal of the third deck from inventory was not about staffing or security concerns. Excess inventory was a factor in creating the perception of reduced value - not just of any A's ticket, but of all pricing tiers as well. Once pricing tiers and their value are well-established, demand should rise and that terrible standard deviation figure should drop, perhaps as much as 50%. That should, in turn, create a stable fanbase to which the A's and their sponsors can market.

Of course, this completely ignores on-field performance. That's what it's supposed to do, because records can vary from year to year. Some years teams make the playoffs. Then again, they could lose 100 games. Whatever the case, this fanbase stability is supposed to provide a built-in insulation against record fluctuations. Premium seats are often sold in 5-7 year increments with the promise of controlled price hikes. The same could be said for luxury suites. The hope is that should the A's leave the Coliseum in the next 3-4 years, much of the fanbase will be precommitted to the new ballpark, wherever it is in the Bay Area.

When looking at the model from a distance, it bears a kinship with the "Moneyball" philosophy. It's about identifying market inefficiencies and exploiting them whenever possible. If basic microeconomic ideas can be applied successfully to the running of the baseball side of a franchise, it only makes sense that they also be properly applied to the place they were developed in the first place: the business side.

Coming tomorrow: Crowd noise measurements