Just Noticeable Difference, engineering concepts

Just Noticeable Difference, JND for short.

We all sort of know this just by being listeners, but the concept of Just Noticeable Difference wasn’t a topic I’d seen mentioned on the forums, and I thought I’d give it a shout out.

The wikipeida article about JND – not a great article in itself – begins:

Just Noticeable Difference
in the branch of experimental psychology focused on sense, sensation, and perception, which is called psychophysics, > a just-noticeable difference or JND is the amount something must be changed in order for a difference to be noticeable, detectable at least half the time (absolute threshold).> [1] This limen is also known as the difference limen, differential threshold, or least perceptible difference.[2]
https://en.wikipedia.org/wiki/Just-noticeable_difference> …

Music production applications

In music production, a single change in a property of sound which is below the JND does not affect perception of the sound. For amplitude, the JND for humans is around 1 dB (Middlebrooks & Green, 1991; Mills, 1960).

The just-noticeable difference (JND) (the threshold at which a change is perceived) depends on the tone’s frequency content. Below 500 Hz, the JND is about 3 Hz for sine waves, and 1 Hz for complex tones; above 1000 Hz, the JND for sine waves is about 0.6% (about 10 cents). The JND is typically tested by playing two tones in quick succession with the listener asked if there was a difference in their pitches] The JND becomes smaller if the two tones are played simultaneously as the listener is then able to discern beat frequencies. The total number of perceptible pitch steps in the range of human hearing is about 1,400; the total number of notes in the equal-tempered scale, from 16 to 16,000 Hz, is 120.

JND is briefly related to amplitude and to pitch, but anything – EQ, Compression, FX, Pan – will have a just noticeable difference factor as well. I’m finding it interesting to see how JND relates to the Equal Loudness Contour.

Aside from possible engineering use, JND, also applies to product marketing. Consider this when asking for new features or re-asking for things you still believe should be part of Cubase but are not.

Take care :slight_smile:

The link in this https://www.steinberg.net/forums/viewtopic.php?f=198&t=118333 thread lets you test this kind of thing. I might disagree with the 1dB cutoff definition of JND, I was able to reliably get down to 0.5 dB.

Maybe it comes down to differences in the testing protocol …

Thanks, interesting subject. As I think about it, there is a threshold for a JND, but hearing such a slight difference usually doesn’t matter very much. So there’s also a threshold for a noticeable difference that actually impacts your impression. So sometimes when I’m mixing, I’ll be playing with levels and I find I have to make larger changes than slight changes to see what I like, and then usually temper those changes to a level that just makes an impact. Another example, I read a review in SoS on a Steven Slate plugin that emulates famous analog mixing consoles, and before and after samples were provided. Listening carefully to the samples, I could hear a very subtle difference, but I couldn’t actually say I liked it better than the original.

I’d visited that site you mentioned but will have to return. I think skilled listeners and engineers will be able to beat the statistical JND norms because it’s only noticeable about half the time. I once had a Yamaha amplifier and it claimed to have a “noticeable difference” for every increment of the volume dial, which was detented. I remember thinking that I could sometimes hear a difference and sometimes not, but, looking back, I’m sure my evaluation was influenced by the frequencies on the vinyl records I was listening to with it. The dB and the Equal Loudness contour is what I really work with, but I thought a mention of JND was interesting to bring up. I’m trying to integrate it into my overall understanding.

I’m glad you found it interesting. I think it’s one more way of looking at the sounds we’re working with and making decisions about the typical factors – level, pan, eq, compression, FX. As I continue to develop, I’m finding I’m more reliant on traditional values such as dB and the equal loudness contour, but I feel JND might be useful in some situations, for example, in helping to sort out tricky EQ decisions.

I love Sound on Sound but don’t recall that particular article. When I hear “emulated analogue” that’s fine and the plug-ins look nice on screen, and do sound great. However, I have to ask. what’s really going on with the waveform? In short, in many cases some kind of distortion is being introduced. So, that’s how I think about it. Emulated analogue means adding distortion of some kind. I like and use the stock plug-ins like Magneto, but it’s an effect and I don’t really need the cool tape-machine graphic if my ears are telling me it’s right. I’m sure you know exactly what I mean. Anyway, maybe JND is just one more concept to have in the tool kit.

I also thought it was interesting to see how JND might apply to the further development of Cubase and other Steinberg products. Take care. :slight_smile: