A least-squares fit is presented of 1105 far-infrared and 2860 microwave transitions in acetaldehyde, which sample rotational levels in all torsional states below the lowest-frequency small-amplitude vibration n 10 . Four-fifths of these transitions, involving torsional states below the barrier (£ t £ 2), were treated in an earlier publication; here the theoretical model is further tested by extending the data set to include the £ t Å 3 and 4 states above the barrier. The new data set includes (i) 224 £ t Å 3 R 2 far-infrared transitions, (ii) Nizhny Novgorod RAD-2 a-type and b-type submillimeter transitions in £ t Å 2, which make more precise DK Å {1 intervals in this last torsional state below the barrier, (iii) RAD-3 a-type submillimeter transitions in £ t Å 3 and 4, and (iv) microwave and submillimeter measurements or remeasurements from NIST and Lille of transitions with £ t £ 4. The global fit, which uses an improved version of the computer program previously applied to the £ t £ 2 data, gave a weighted overall standard deviation of 1.21 with 55 adjusted and 2 fixed parameters. Residuals from the fit were close to experimental uncertainties for the infrared wavenumber measurements and for microwave and submillimeter frequency measurements below the barrier, but some residuals reached several MHz or more for frequency measurements involving levels near n 10 . We have attempted to achieve a qualitative understanding of the numerical results by presenting a general overview of internal rotation energy levels above the barrier and a theoretical discussion of torsion-rotation interactions among these levels.