Brett

I'm quite new to working with MSP, but had an idea to create a semi-real time backwards masker to play the world in reverse. I'm just throwing it out there to see if anyone has any suggestions or better ways of doing things.

backwards-masking-or-buffer-for-newbie

'A semi-real time backwards masker to play the world in reverse' you say?

Ok, its a mouthful, but yes. Semi-realtime because you have to have some small interval to slice up the world by in order to reverse it. Here it is set to 500ms.

The world backwards is a strange place. Try saying "nee-nah" into the instrument.

Ok, its a mouthful, but yes. Semi-realtime because you have to have some small interval to slice up the world by in order to reverse it. Here it is set to 500ms.
The world backwards is a strange place. Try saying "nee-nah" into the instrument.


i was under the impression that backwards masking was always happening in real time.... no need for a patch there!

As for your patch... I'm not completely sure what your intent is. The basic idea to your patch seems to be that if you record a sound and then play it back in reverse with the original sound..you will get some kind of effect.

However, this is not what backwards masking is. The book 'The Science of Sound' by Rossing Moore and Wheeler defines backwards masking as a psychoacoustic term referring to "the masking of a tone by a sound that begins a few milliseconds later. A tone ca be masked by noise that begins up to ten milliseconds later, although the amount of masking decreases as the time interval increases. Backward masking apparently occurs at higher centers of processing where the later-occurring stimulus of greater intensity overtakes and interferes with the weaker stimulus." (page 114)

The "backwards" part of backwards masking doesn't refer to a reversal of sound..its just that the initial sound seems to mask sounds that come later.

Anyways, please be more specific as to what your goals and problems are and we can be of some help.

I did do a couple of quick tests with a little repeating blip noise (in place of adc~) 

and noticed you were having some problems playing the reverse sounds at the right pitch. I would recommend trying to use a combination of record~ and wave~ rather than the poke~ method. Record also gives a nice sync wave out of its output which you could use to sync to wave~. Look into the looping function of record, as well. 

i was under the impression that backwards masking was always happening in real time.... no need for a patch there! 

As for your patch... I'm not completely sure what your intent is. The basic idea to your patch seems to be that if you record a sound and then play it back in reverse with the original sound..you will get some kind of effect. 

However, this is not what backwards masking is. The book 'The Science of Sound' by Rossing Moore and Wheeler defines backwards masking as a psychoacoustic term referring to "the masking of a tone by a sound that begins a few milliseconds later. A tone ca be masked by noise that begins up to ten milliseconds later, although the amount of masking decreases as the time interval increases. Backward masking apparently occurs at higher centers of processing where the later-occurring stimulus of greater intensity overtakes and interferes with the weaker stimulus." (page 114) 

The "backwards" part of backwards masking doesn't refer to a reversal of sound..its just that the initial sound seems to mask sounds that come later. 

Anyways, please be more specific as to what your goals and problems are and we can be of some help. 

I did do a couple of quick tests with a little repeating blip noise (in place of adc~) 
and noticed you were having some problems playing the reverse sounds at the right pitch. I would recommend trying to use a combination of record~ and wave~ rather than the poke~ method. Record also gives a nice sync wave out of its output which you could use to sync to wave~. Look into the looping function of record, as well. 


Thanks for the time to test and respond Nick!

Like I said, I'm new new new. New to the terminology, new to the methods, new to the ideas. I think originally I wanted to create a backwards echo of the world.. like tapin~ but reverse. The goal simply was to familiarize myself with buffer~ and experiment. Now thanks to your suggestions I will play somemore!

Thanks for the time to test and respond Nick!
Like I said, I'm new new new. New to the terminology, new to the methods, new to the ideas. I think originally I wanted to create a backwards echo of the world.. like tapin~ but reverse. The goal simply was to familiarize myself with buffer~ and experiment. Now thanks to your suggestions I will play somemore!


> I think originally I wanted to create a backwards echo of the world.. 

Peter Reid has some nice abstractions for tapin~/out~ based reversing, 

they don't do what you intend straight away but worth checking out.

Am 29.07.2007 um 21:40 schrieb Brett:
>  I think originally I wanted to create a backwards echo of the world.. 
> like tapin~ but reverse.

Peter Reid has some nice abstractions for tapin~/out~ based reversing, 
they don't do what you intend straight away but worth checking out.

> However, this is not what backwards masking is. The book 'The

> Science of Sound' by Rossing Moore and Wheeler defines backwards

> masking as a psychoacoustic term referring to "the masking of a

> tone by a sound that begins a few milliseconds later. A tone ca

> be masked by noise that begins up to ten milliseconds later,

> although the amount of masking decreases as the time interval

> increases. Backward masking apparently occurs at higher centers

> of processing where the later-occurring stimulus of greater

> intensity overtakes and interferes with the weaker stimulus."

Oh I am glad someone you said that Nick! This is one of my personal

"hot buttons", and that usually is a danger sign for list-posting. 

"backwards masking" is indeed a real psychacoustical effect, but

the notion that "backmasking" (which I guess is the name given to

reversing audio) has cognitive currency seems a bit of a stretch to

And if it did, we'd probably all be worshipping at the Church of

PS: Don't get me wrong, reversed audio surely often does sound

nifty! I'm always a sucker for the backwards-reverb trick myself.

> However, this is not what backwards masking is. The book 'The
> Science of Sound' by Rossing Moore and Wheeler defines backwards
> masking as a psychoacoustic term referring to "the masking of a
> tone by a sound that begins a few milliseconds later. A tone ca
> be masked by noise that begins up to ten milliseconds later,
> although the amount of masking decreases as the time interval
> increases. Backward masking apparently occurs at higher centers
> of processing where the later-occurring stimulus of greater
> intensity overtakes and interferes with the weaker stimulus."
> (page 114)

Oh I am glad someone you said that Nick!  This is one of my personal
"hot buttons", and that usually is a danger sign for list-posting. 
"backwards masking" is indeed a real psychacoustical effect, but
the notion that "backmasking" (which I guess is the name given to
reversing audio) has cognitive currency seems a bit of a stretch to
me.

And if it did, we'd probably all be worshipping at the Church of
Satan (or is that Nataz...) right?

PS:  Don't get me wrong, reversed audio surely often does sound
nifty!  I'm always a sucker for the backwards-reverb trick myself.


Quote: misery4brett@gmail.com wrote on Sun, 29 July 2007 13:40

----------------------------------------------------

> Thanks for the time to test and respond Nick!

> Like I said, I'm new new new. New to the terminology, new to the methods, new to the ideas. I think originally I wanted to create a backwards echo of the world.. like tapin~ but reverse. The goal simply was to familiarize myself with buffer~ and experiment. Now thanks to your suggestions I will play somemore!

you can actually read from tapin~ backwards by sending it the right values in message form, no need for wave~ or play~.

Quote: misery4brett@gmail.com wrote on Sun, 29 July 2007 13:40
----------------------------------------------------
> Thanks for the time to test and respond Nick!
> Like I said, I'm new new new. New to the terminology, new to the methods, new to the ideas. I think originally I wanted to create a backwards echo of the world.. like tapin~ but reverse. The goal simply was to familiarize myself with buffer~ and experiment. Now thanks to your suggestions I will play somemore!
----------------------------------------------------

you can actually read from tapin~ backwards by sending it the right values in message form, no need for wave~ or play~.


Yes....except I think that I got it wrong as well...as the definition states- backwards masking is the later sound masking the previous sound... I knew that, but I wrote it wrong (not the definition, but my interpretation). 

i don't know if you'll find this interesting,- but here is a tapin-out solution in reverse....

That's exactly it. Wouldn't mind an explanation as to how it works if you can.

> I'm quite new to working with MSP, but had an idea to create a

> semi-real time backwards masker to play the world in reverse. I'm

> just throwing it out there to see if anyone has any suggestions or

As you do not prevent clicks, you can have this result much easier, just 

record into a single buffer~ with loop recording:

Brett schrieb:
> I'm quite new to working with MSP, but had an idea to create a
> semi-real time backwards masker to play the world in reverse. I'm
> just throwing it out there to see if anyone has any suggestions or
> better ways of doing things.

As you do not prevent clicks, you can have this result much easier, just 
record into a single buffer~ with loop recording:

-- 
Stefan Tiedje------------x-------
--_____-----------|--------------
--(_|_ ----|-----|-----()-------
-- _|_)----|-----()--------------
----------()--------www.ccmix.com

Quote: misery4brett@gmail.com wrote on Mon, 30 July 2007 20:28

> That's exactly it. Wouldn't mind an explanation as to how it works if you can.

I've included some explanation, hope it helps !

I agree that a buffer~ solution might be easier, but if you need sync... This solution can be synched sample accurate, all the way thru...

Quote: misery4brett@gmail.com wrote on Mon, 30 July 2007 20:28
----------------------------------------------------
> That's exactly it. Wouldn't mind an explanation as to how it works if you can.
----------------------------------------------------

I've included some explanation, hope it helps !
I agree that a buffer~ solution might be easier, but if you need sync... This solution can be synched sample accurate, all the way thru...

example with windowing, to avoid clicks...

Thanks again for all this spleef. I guess I'm still not understanding why running the phasor and multiplying it by the tapin~ buffer amount -- giving a ramping of 0-3200 over a period of time -- will cause the buffer to be read backwards. I also don't get why there is no crossover of the buffer being written forwards while it is being read backwards. I tried to account for this in my patch by having 2 buffers. I think there is something fundamental I am missing here!

Backwards Masking OR Buffer~ for newbie