The issue of the correct pitch of tango recordings first came to our awareness when we noticed that LP transfers of old shellacs had been sped-up, raising both the pitch and the tempo. Later we discovered that the pitch of the original recordings was itself suspect because of technology issues. Surprise surprise, the same technology issues also affected jazz recordings.

The most celebrated case is that of Louis Armstrong’s early recordings with his Hot Five and Hot Seven on the Okeh label in 1925-1927. People noticed that Cornet Chop Suey appeared to be in the key of E, which was a very strange choice for a trumpet. Thinking that the transfer must have been sped up, the jazz community first thought that the correct key was E flat – an easy key for a trumpet. This reduced the tempo, leading to the feeling that the Hot Five had played at a relaxed, laid-back tempo. Similarly, Big Butter and Egg Man played back in the key of F#. Surely, the correct key was F.

However we now know that all the early recordings on the Okeh label were made at a speed closer to 80bpm, which meant the transfers made at 78rpm were not too fast, but too slow. Cornet Chop Suey and all the recordings made on Okeh in 1925-1926 – so all the recordings of the Hot Five – actually needed to be sped up. Early reissues were at the wrong pitch, although Sony have now fixed this.

Just as with tango, incorrect pitch was found not to be just a technical question. Because of the impact on tempo, it affects the feeling of the music as well – just as it does with tango (see my primer on this topic). And that’s why it matters.