Author Topic: Useful stuff that can be done with inverted samples  (Read 8287 times)

Offline Saga Musix

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Useful stuff that can be done with inverted samples
« on: August 08, 2010, 20:27:52 »
The "invert sample" button is still quite new, and many people might ask why on earth you would want to invert the phase of a sample. Well, there are a few cool things you can do with inverted samples, I'll just explain two, maybe some of you have more interesting ideas to share?

1. Creating fake surround sound
Probably the oldest use of inverted samples, at least in the tracker scene. Take a sample and copy it into a new sample slot, and the invert it. Pan one sample hard left, and the other sample hard right. Now play them at the same time, et voilà, you have something that sounds quite spacey. This is in fact the same thing as the S91 command does in stereo mode (not in quad mode), and a dolby surround receiver can forward such audio signals to the rear speakers. This is a bit useless since there's the S91 command these days, but still... :)

2. Creating a high-pass filter
This is probably a less known trick, but it works just as well. In situations where you have to be compatible to Impulse Tracker, you might still want to use an highpass filter effect. As you may know, Impulse Tracker only provides a lowpass filter. However, instead of just pre-recording highpassed sequences, you can as well make use of the lowpass filter, using inverted samples! All you need is a sample and an inverted copy of the sample. Both have to be played at exactly the same panning position. One sample can be played as-is, and you can apply a lowpass filter on the other sample. Since it cancels out the low frequencies of the other sample, you practically get a highpassed sound.

Examples: ftp://ftp.untergrund.net/users/sagamusix/openmpt/resources/modules/inverted.it
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Offline jmkz

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Useful stuff that can be done with inverted samples
« Reply #1 on: August 08, 2010, 22:15:26 »
Thank you so much!! I don't need ask for a vst highpass filter, so i can release a module soon... You saved me time and that's a useful trick !!

Offline Saga Musix

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Useful stuff that can be done with inverted samples
« Reply #2 on: August 08, 2010, 22:19:06 »
Quote from: "djmakas"
Thank you so much!! I don't need ask for a vst highpass filter, so i can release a module soon... You saved me time and that's a useful trick !!

Well, MPT does have a highpass filter (just look in the instrument settings) - the second advice is just thought for releasing music which requires a highpass filter and is supposed to be released in IT format - which doesn't support VSTs natively as well.
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Offline jmkz

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Useful stuff that can be done with inverted samples
« Reply #3 on: August 08, 2010, 22:24:29 »
Quote from: "Jojo"

Well, MPT does have a highpass filter [...]


Yeah, I know, but exported in compatible mode resets to the default channel filter, and some other things, but the intention is being compatible with other players or trackers too.

Offline Saga Musix

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Useful stuff that can be done with inverted samples
« Reply #4 on: August 08, 2010, 22:25:23 »
I wonder why you mentioned the VST thingy then...? Because those get removed too with compatibility export. I'm a bit confused :s :)
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Offline jmkz

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Re: Useful stuff that can be done with inverted samples
« Reply #5 on: August 08, 2010, 22:36:14 »
Quote from: "Jojo"

2. Creating a high-pass filter
This is probably less-known, but works amazingly well. In situations where you have to be compatible to Impulse Tracker, you might still want to use an highpass filter effect. As you may know, Impulse Tracker only provides a lowpass filter. However, instead of just pre-recording highpassed sequences, you can as well make use of the lowpass filter, using inverted samples! All you need is a sample and an inverted copy of the sample. Both have to be played at exactly the same panning position. One sample can be played as-is, and you can apply a lowpass filter on the other sample. Since it cancels out the low frequencies of the other sample, you practically get a highpassed sound.


Well, I was going to come here looking for a VST effect of highpass, and I read your post, because I am avoiding render a sample with highpass filter for that is the VST plugin (was going to ask for one)

Offline jmkz

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Useful stuff that can be done with inverted samples
« Reply #6 on: August 08, 2010, 23:13:00 »
Interesting... I was thinking, after seeing the example, it would not work for as I want or do not know how. The original sample to which I apply the filter sounds well without it, but not like I have planned. Also I consider this nice, I probably release a module with this trick (i don't promise nothing) :)

Offline Saga Musix

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Useful stuff that can be done with inverted samples
« Reply #7 on: August 08, 2010, 23:16:11 »
Well, you can achieve exactly the same sound with the lowpass filter method as with the built-in highpass filter. Well, at least if you don't use randomized panning, because that will essentially destroy the concept. But if you take a sample and create an inverted copy, you should be able to highpass it using Zxx or filter envelopes or whatever...
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Offline jmkz

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Useful stuff that can be done with inverted samples
« Reply #8 on: August 08, 2010, 23:38:22 »
Does this is exported with the compat. export ?  (i guess it would)

Offline Saga Musix

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Useful stuff that can be done with inverted samples
« Reply #9 on: August 08, 2010, 23:48:27 »
As I said, this is the method to get a highpass filter into IT files. IT supports lowpass filter via Zxx, filter envelope and the instrument settings.
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Offline jmkz

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Useful stuff that can be done with inverted samples
« Reply #10 on: August 09, 2010, 00:02:36 »
Please check this module. What do you think? (Instr. 01 ch 16~18 )

Offline Saga Musix

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Useful stuff that can be done with inverted samples
« Reply #11 on: August 09, 2010, 00:15:31 »
That works... (link removed)
I just duplicated every channel and added a new sample (inverted)+instrument (lowpass filter at 320hz). That's the same as using a 320hz highpass filter as you did.
BTW, I wouldn't use the S99 effect (if you want reverb, render it directly into the sample) - not only because it's not supported by other players, but also because it's not even supported properly in MPT :) And by that I mean that S99 just enabled reverb, but you don't know which reverb it enables. There is a variety of reverb presets which the user can choose, but you have in fact no control over that.
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Offline jmkz

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Useful stuff that can be done with inverted samples
« Reply #12 on: August 09, 2010, 00:27:32 »
Yes! Nice Jojo 8)  Thanks! For the reverb I will remove the S99, in that case does not influence at the overall song, I will apply the trick to the all other patterns. haha! stills great!  :D

Offline jmkz

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Useful stuff that can be done with inverted samples
« Reply #13 on: August 09, 2010, 06:51:09 »
Quote from: "djmakas"
[...] I probably release a module with this trick (i don't promise nothing) :)


Well, here is the song.

Offline Skaven

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Re: Useful stuff that can be done with inverted samples
« Reply #14 on: October 29, 2011, 14:47:16 »
One sample can be played as-is, and you can apply a lowpass filter on the other sample. Since it cancels out the low frequencies of the other sample, you practically get a highpassed sound.
And if you don't have access even to a lowpass filter AND you want to save memory, you can heavily downsample the inverted sample. Dowsampling reduces the sample rate, which removes the high frequencies, so it basically has the same effect as a lowpass filter (though the sound's grittiness is greatly affected by the interpolation method you may be using).