Saab 9-5 to the base models and the Aero. Six-speed manual transmission was not offered in first-generation 9-5s. In 2005, an updated version of the 2.0 L turbocharged I4 was introduced in the European market together with the 2006 9-5. The engine was sold as "2.0T BioPower", optimized to run on E85 producing 132 kW (180 hp) at 5500 rpm. There was also a 2.3T BioPower version sold from 2007. It was also introduced in Australia. There is a Saab 9-5 E100 Concept, based on the turbo 2.0. The 9-5 introduced Saab's Active Head Restraints (SAHR), which moved up and forward to
7-limit tuning Young's "The Well-Tuned Piano", Ben Johnston's String Quartet No. 4, and Lou Harrison's "Incidental Music for Corneille's Cinna". The Great Highland Bagpipe is tuned to a ten-note seven-limit scale: 1:1, 9:8, 5:4, 4:3, 27:20, 3:2, 5:3, 7:4, 16:9, 9:5. In the 2nd century Ptolemy described the septimal intervals: 7/4, 8/7, 7/6, 12/7, 7/5, and 10/7. Those considering 7 to be consonant include Marin Mersenne, Giuseppe Tartini, Leonhard Euler, François-Joseph Fétis, J. A. Serre, Moritz Hauptmann, Alexander John Ellis, Wilfred Perrett, Max Friedrich Meyer. Those considering 7 to be dissonant include Gioseffo Zarlino, René Descartes, Jean-Philippe Rameau, Hermann von Helmholtz, A.