Add 'audio_delay' FX

[mondeja]

This is a common effect working with audio. Keep in mind that this effect does not fit a loop FX behaviour, since the sound is multidimensional because you can have multiples copies playing at the same time. Even with an offset attribute in current loop FX this effect would be impossible to achieve.

• I have provided code that clearly demonstrates the bug and that only works correctly when applying this fix
• I have added suitable tests demonstrating a fixed bug or new/changed feature to the test suite in tests/
• I have properly documented new or changed features in the documentation or in the docstrings
• I have properly explained unusual or unexpected code in the comments around it
• I have formatted my code using black -t py36

[coveralls]

Coverage increased (+0.09%) to 67.401% when pulling dacb02a on mondeja:audio_delay-fx into b519687 on Zulko:master.

[tburrows13]

I'm not sure about this one... isn't it basically the same as #1358? I wonder if it would make more sense to implement this one in loop, if you think that the decay would work there?

[mondeja]

I'm not sure about this one... isn't it basically the same as #1358? I wonder if it would make more sense to implement this one in loop, if you think that the decay would work there?

Keep in mind that is not the same as a loop. In a loop, a whole clip is played and after that starts another copy. In a delay effect, you can have multiple copies playing at the same time.

[tburrows13]

Keep in mind that is not the same as a loop. In a loop, a whole clip is played and after that starts another copy. In a delay effect, you can have multiple copies playing at the same time.

Oh right, in which case this is fine. There would be no way to implement loop with #1358 that allows a 'negative' gap, so this is a good way to do it.

I have a feeling that the description or name could be improved, but I can't take that further right now. Depending on how those change, perhaps the default decay should be 1?

[mondeja]

I have a feeling that the description or name could be improved

The description sure, but the name is a standard in music production and sound treatment, it feel to me that is the right name.