Brent said the tri-tone is a “diminished fourth,” it is actually an augmented fourth, which is enharmonically the same thing as a diminished fifth.

A “diminished fourth” from C would be Fb or E natural, which is actually a Major third. An AUGMENTED fourth from C would be F#, as augmented means to increase or AUGMENT the distance between notes, diminished means to decrease or DIMINISH the space between notes. Thus a diminished fifth above C is Gb, which is enharmonically the same note as F#.

Happy Trails.

Am i the only one who hears a “bomb” sound at 0:19, 0:39 and at 0:59-1:00(don’t know if it reoccurs)?

A Tritone really is a diminished fifth – or enharmonically, an augmented forth, at least in 12 tone equal temperament. That temperament probably didn’t exist at the time of the “Devil” condemnation, though. Most intervals near 600 cents sound pretty alien, because it’s a big gap in the harmonic sequence (11th harmonic comes closest first).

I made some more Shepard tones recently for the WFMU Locked Groove record “Running in Place,” some ascending, some descending. Shepard tones seemed a natural for a locked groove record!

Thanks for your input. You comment is kind of extreme. I posted all of Brent’s words including updating the original post with his specific links and comments. I was thinking that being honest with my errors and showing the corrections would be a good way to satisfy my inaccuracies. Please tell me how else I can remedy this.

Sincerely,

Margaret

The devil’s tone is the tri-tone, not the shepherds tone.

Thanks to Brent for clearing it up.

Firstly, Travis, the tritone is a diminished fourth (not fifth). Eg: the interval of C and F#. It is called the tritone because it is an interval of three tones or 6 semitones. This is indeed what people have referred to as the “devil tone”, among other nasty names. However, it was considered evil long before the Catholic Church deemed it such (in their usual blinkered reactionary fashion). A lecturer of mine once quoted an ancient greek text, that described the tritone as a sound (I’m paraphrasing a translation here!) “so foul as to seem to emanate from the depths of hell itself”. I really wish I could remember who said this, (and indeed what was said!) – sorry. Anyhow, it was the ancient greeks that at least classified this sound as sinister, or “bad”. On this subject, It seems to me that without dissonance, we would have no opposite state to consonance, rendering both concepts meaningless.

In her reply, Margaret quotes a Wikipedia page, or at least text that was used on the Wiki page for “Tritone Paradox”:
“The tritone paradox is an auditory illusion in which a sequentially played pair of Shepard tones separated by an interval of a tritone, or half octave, is heard as ascending by some people and as descending by others.”
The tritone paradox is a recognised phenomenon identified by psychologist Diana Deutsch. It is an auditory illusion corresponding in nature to the optical illusion known as a “Necker Cube”, which is a line drawing of a cube in perspective that contains no depth perception information. The well-known effect of this is that we can actively change our perception to alternate which of the facing planes is the front face of the cube, but we cannot see both as the front face at the same time. Similarly, with the tritone paradox, identical tones can be heard by different listeners as either a descending or ascending interval. It is also possible for us to alter our perception to hear either an ascending or descending sequence, but it seems it is harder for people to achieve this in the auditory domain than in the visual.

Regardless, the audio example here is of a continuous Shepard-Risset glissando (not a Shepard scale as stated). The source page for this sound file is here . It is in French. You can find the Wiki source page here . The sound example is also composed of a minor chord of glissandi, not just of a single Shepard-Risset glissando. It is the inherent shift in amplitudes (or loudness, determined by a logarithmic bell curve centred at a fixed frequency) of the different octave frequencies that causes the illusion that the pitches are continuously descending, but ultimately going nowhere.

The score seems to indicate this is an ascending glissando of Shepard tones, but I don’t think this is the case. I’m not sure if this score relates to the sound example – maybe Margaret could shed some light on this.

The tritone, or devil’s tone, the tritone paradox, the Shepard scale and the continuous Risset glissando are all separate concepts.

You can read more about the work of Diana Deutsch here . Despite the academic snobbery surrounding Wikipedia, I do think it is an excellent resource. And, hey, it’s the people’s encyclopedia, which is what the internet should be all about. You have to be careful though. Once a friend of mine edited the Rolling Stones Wikipedia page – He and I were listed as band members for about 30 minutes until someone restored the correct info!

By the way, thanks for your work on the Sound is Art site, Margaret. I dig it, and I spend far to much time listening to your posts rather than working on my research.

Cheers,
Brent.