Hi

So for my university assignment I had to make any patch I wanted, the only condition being that it is controlled only with a slider and a button (bang). I made a synth thinking that it would be fairly easy to create a system in which the slider could select different parameters for itself to control which could then be activated by the bang.

After trying for a bit I was at a pure loss so posted in the pure data group on facebook looking for help. As always, the pure data community provided help instantly and someone created the exact patch that I need. However, I need to integrate it into my synth patch, and I need to add more parameters and as a pure data (and programming) noob the way it works is going COMPLETELY over my head and to use it in (or make a version of it for) my assignment I have to understand it.

Is there any chance someone could have a look and explain in noob terms step by step what is happening in this patch? Thanks in advance so much!
slidergui.pd

@djpersonalspace Well....... the order of operations is the most important thing to understand in any Pd patch. I recommend reading this until you get to chapter 2.9...... http://puredata.info/docs/manuals/pd/x2.htm
which will give you a great understanding of what is going on "under the hood".
Then right-click and select "help" for every object so that you understand what they are doing.
Try putting [print] objects at the outlets of objects to see what messages they send as you move the slider and click on the bang.
Remember always that messages get sent down the rightmost part of any chain until they get to the end of the chain, and then the next rightmost and finally the left part of the chain....... and then the operation will be complete.
Then come back for help understanding the patch if there is something that escapes you...... but I think you will not need to.
David.

Awesome thanks for the advice

@djpersonalspace Glad you came here, as i like the forum better than the FB group. I made the patch you posted above.

So the right part of the patch is only to set the slider to the nearest option, so you can forget about this part for a moment. If you delete the cord from the right outlet of the [t f f] you only have the basic function of the patch.

So what happens there is the value of the slider is coming from the [r $0-selection]. The send is set in the slider properties. I use $0 in every send/receive, but you may not need this at the moment, so you can simply rename both send and receive.
The value is now send to the left if below or equal 128 or to the right if above by [moses].

On the right side, the expression determines in which area the value is by subtracting 128 and dividing through the range and multiplying by 9. These values have to adjusted if you change the range of the slider or the number of options to select. The resulting number is then stored in the [f], the bang sends it to [list prepend].

If the value is 128 or below it will be combined to a list with the number of the option by [list prepend] so that the option number comes first. [route] than sends the value to the correct outlet. That is all.

The right side that locks the value to the nearest option is a bit trickier. Here the value is again determined by the expression. If you still move the slider, the [pipe] will be cleared again and again. But if you stop moving the slider, [pipe] will set the value to the nearest option after 50 ms.

Hi

Glad you found me

Awesome, I can't thank you enough for all this help. I really want to get into pure data as I love how powerful it is and how creative you can be but sometimes it can be a bit hard to get my head round as I come from a musical background and not a programming one.

I (more or less) understand everything except the expressions. I have looked up how expressions work but am still struggling to understand exactly what they are doing and why. I kind of get the one on the expression connected directly to the moses is basically determining which part of the slider you are clicking on right?? The expression on the left, however, coming out of the t f f, I am struggling to understand the formula in it.. Is it basically just estimating which point you are closest to?

Thanks again! and sorry for my poor understanding, I have only started using pure data in January!

Cheers

@djpersonalspace Yes, exactly. The second expression basically just reverses the first one. So from the actual value, the first expression gives the number of the section you clicked on. The second expression takes this number and makes a value out of it again.

There is one trick though: As the number is rounded down by int(), the (451-128)/(9*2) part adds the height of half a segment to the value, so you land in the middle of the section. I put the comments with the ---- lines also in the middle of the section. So now the slider jumps upward if you are below the middle and downward, if you are above

Edit: int() is not that important here, the second expression would give the lower boundary of each section anyway.

Brilliant! Thanks again, I may return to you with some more questions about this patch over the next week or two if that is okay

Hi

So I have edited it to add more parameters and make it bigger. I have put in a parameter called 'sequence randomiser' and set it up so that when you bang it, you can select a key for the sequence to be randomised in from the Min-Max section at the bottom of the slider, you can then use the bang again to select that sequence.

What I would like to do is implement is a similar system to the one on the right hand side of the patch, which makes the slider snap to each parameter, on MIN-MAX section, only for the time that the 'sequence randomiser' parameter is selected. However, I am struggling to get my head round the expr which is calculating this process so am unable to modify it in order to effect the MIN-MAX section. I've attached the patch so you can have a look.

If you have time to have a look at this would be totally great thanks in advance Synth_Slider_Controller.pd

So my general feeling is that you might be getting a bit caught up on the [expr] object. It's a super powerful and useful object but it can also make things a bit opaque for beginners.

I would suggest breaking it apart so you have a better understanding of what's going on. For example, if you take the two [expr] objects that are taking the slider data and doing the main calculations, you can turn them into a series of operator objects that make everything a bit more clear (and also makes it a bit easier to adjust individual parameters).

but to return to your last question - the part that's most important in terms of the snapping feature is the [set $1[ message, which is being sent to the [s $0-setselection] object. I'll mock up a possible solution for you in a second.

So I think this is what you're after?

Essentially it's the same as the previous screenshot, in the sense that it goes through the same set of calculations but in reverse, and then use that to set the slider after a short delay.

two other things:

• the [send] and [receive] objects can only have one argument (with no spaces). So your [s seq key17] and [r seq key17] objects are really just functioning as [s seq] and [r seq]. I don't think this is making any difference in your patch now, but you could get confused in the future if you try and use a similar naming convention.

• also, to reinforce my previous advice regarding [expr], you're using an [expr] object when you really don't need one. coming from [r seq key17] and going into a toggle controlling a [spigot]. there is a dedicated operator object that does this same exact thing: [==]
  again, this doesn't really matter but it might help you understand how the patch is working better.

Hey that's great thanks! I will try that out I have now edited it so that theres more room in the MIN-MAX bit for setting parameters so its less fiddly, so the numbers will be a bit different but I think I'm pretty much understanding how it works now...just need to have a mess around with it. Thanks again!