Difficulty understanding chapter 1 Activity Analysing Algorithms

[dthomas86]

I am fairly new to programming in Max/Msp and find this book a great help it is clearly laid out and great with the activities it provides.
  But know I have come to a problem I just can not understand (probably has a very simple answer).  On both Activities A and B of the Analysing algorithms in Chapter One, I just can't seem to grasp the answer.  I have looked at the table of differences between the equally tempered chromatic scale and the natural scale but can seem to see how it correlates to the patch.  When C# is pressed on Activity A then groove plays back at normal speed the B plays at -1 which reverses the sample but beyond the B the sample is sped up in reverse.   Going beyond the C# the sample is sped up but in non reverse. 
  Sorry for sounding dull but I am struggling to see the correlation between the table you stated to look at in section 1.4 of the theory.

  Cheers for the help

[Maurizio Giri]

Don't let the kslider object mislead you. It is not important the note name, but the corresponding MIDI value.
When you press c# on Activity A, you generate the value 1 (MIDI equivalent of a very low c#), and this value (turned into a signal) goes  into to groove~ object. Because of this, the groove~ object plays the audio file at normal speed.
To understand what goes on in these patches, look at the numbers sent to the groove~ object.

m

[dthomas86]

Thank you for your reply Maurizo,
  But what does it mean by the successive keys correspond to something else rather than semitones?  And how does this related to Table D in section 1.4 of the theory chapter?

  Thanks for the help I appreciate it very much.

[Maurizio Giri]

But what does it mean by the successive keys correspond to something else rather than semitones?  And how does this related to Table D in section 1.4 of the theory chapter?

Well, the answer to these questions is part of the exercise!

We decided not to give answers, because we think that it is more important to try to solve the exercise rather than knowing the answer itself.
However, by the end of chapter 3, you'll find that the question is a very easy one.

m

[Saturnin79]

Same for me. I'm new to Max/MSP - hey that's why i grabbed the book - and I don't understand what is happening in this patch, well, what the problem is.

I think that not giving any answer doesn't help. Same for the reverse engineering exercises. You never know if you are right or wrong. And you may stay stuck for hours. Reminds me of some boring class exams... which is not what I expected.

So I just left the book and closed Max/MSP, feeling frustrated - once more.

Unfortunately your book didn't help, for me...

[Maurizio Giri]

Dear Saturnin79,

I would suggest you to don't give up! There are lot of things you can learn from the book.
As I said the "correct" answer of the activities is not the important thing: what is important is to try to give an answer.

There are hundred of patches and solutions in the book, the activities are a mere 1-2% of the total, and they are there for the unique pourpose of making the reader reflect about what s/he has learned, what s/he can do with the program.
We worked 5 years on this project, and we believe that this is a route that can really improve your Max/MSP programming skill.

I think that not giving any answer doesn't help. Same for the reverse engineering exercises. You never know if you are right or wrong. And you may stay stuck for hours. Reminds me of some boring class exams... which is not what I expected.

Why stay stuck for hours? If you really can't find the answer, go on with the other chapters and return back later, you'll find the exercises easier!

Btw I forgot to reply to dthomas86, when he asked

But what does it mean by the successive keys correspond to something else rather than semitones?  And how does this related to Table D in section 1.4 of the theory chapter?

The book suggested to "consult the ratios for natural frequencies in Table D of Section 1.4". So you have to compare the numbers generated by the kslider with the ratios of Table D. What are those ratios?
Are the ratios of the Activity A IDENTICAL to those of Table D or are they DIFFERENT? (hint: look at the number box connected to the kslider in the patch of fig. 1.66; does it seem to spit out the same ratios you find in Table D?).
How you would describe the patch ratios? (In your own words, without technicalities).

Still no idea? Don't worry, go on with the book and return back later.

With regard to reverse engineering, well this is part of the "core business" of the sound designer. A sound designer, imho, should learn (among other things) how to recreate (or approximate) a given sound.
Say you find a sound wich is perfect for a particular work you are doing. But you can't use it directly (because is badly recorded, or it is too short, too soft, or it is mixed with unwanted sounds etc.).
Well you can try to reverse engineer it, i.e. recreate it programmatically!

Again, what is important in the "reverse engineering" exercises is not to have the patch that created the sound. It is important to try to recreate the sound "with your hands". Maybe while you try to make a particular sound, you end up with a completely different sound, and maybe this sound is more interesting than the sound you were looking for! All this can improve your skill: just having the original patch does no good.

jut my two cents
m

[Saturnin79]

You're surely right, I'll try not to give up. Theory is very well explained to my opinion, by the way. I've come across difficulties while reading other books (which i won't mention here...) because it was getting too technical, that's not the case here (i have come to the additive synthesis part). I had another problem, while trying to build a patch from scratch, the one that has frenquency jump up to a certain level, play that frequency for awhile, then jump down again. Can this be achieved using a single line~ object  ? That is ok until the frequency has come to its peak but after that ? My idea was to have a bang sent when the frequency peak is reached, which would trigger another line~ object, starting with that frequency then jump down again, but it doesn't work fine...

And that seems a little complicated, by the way...

Please give me some tips...

[Maurizio Giri]

Yes you can have multiple segments with line~. Suppose you want to jump from 220 to 440 Hz in 10 ms, stay at 440 for 1000 ms then return to 220 in 10 ms, you can send this message to the line object: "220, 440 10 440 1000 220 10". The line~ object should be connected at a [cycle~ 220] object.
See also on pages 82-84 of the book.

m

[dthomas86]

@ Saturnin79 don't give up on the book I have learnt more about max/msp in a few weeks than I have learnt in a whole year than I have when trying to learn it myself.  I have also learnt a lot more about digital audio in the few chapters than I have studying it!  Giri and Cipriani have done a wonderful job with this book and max is about pushing your self to the limits and fault finding.  It would be a nice feature though to check if you are correct in someway thats why I like posting up on here to see if I am correct (cause it is a nice feeling to know if you are progressing with your studies and have learnt new things) but I am glad that it has been left out of the book because I probably would have skipped the exercises and gone straight to the answers.