public function countMaxConsecutiveOffBits($scale = null) {
		$max = 0;
		if (is_null($scale)) {
			$scale = $this->scale;
		}
		$c = 0;
		for ($i=0; $i<12; $i++) {
			if (!($scale & (1 << ($i)))) {
				$c++;
				if ($c >= $max) {
					$max = $c;
				}
			} else {
				$c = 0;
			}
		}
		return $max;
	}