sknguy wrote:You can hear from that Youtube clip how much smoother an engine sounds with higher cylinder counts. The BRM had a top RPM pushing 12,000. The V12 topped out at 14,500. And the V10 was creeping into the 19,000 rpm range.
Really impressed with the V16 BRM sound. I wonder if it was as smooth to race as it sounded? Something that sounded odd to me was that even at the much higher 17,800ish rpm speed the V10 still had a slightly lower voice than either the V12 or V16.
Slightly surprising; the V16 should be highest-pitched by quite some margin and of the other two, although they should be very similar, the V10 should sound higher by my calculations (below).
I would expect the tonal pitch of the engine to be strongly related to the number of cylinders filled and emptied per unit time. The tone is actually two tones each at 1/4 this value because you only move a cylinder's content through the intake when the inlet valve is open and you only move it through the exhaust when the exhaust valve is open. Interference between these two tones is guaranteed to occur and will have a strong effect on the sound, and the intake/exhaust design will affect the harmonics you hear above and below the main frequency.
16 * 12000 = 192 000 cylinders/minute = 3.20 c/second (tone 800 Hz)
12 * 14500 = 174 000 cylinders/minute = 2.90 c/second (tone 725 Hz)
10 * 17800 = 178 000 cylinders/minute = 2.97 c/second (tone 742 Hz)