PT2399 FLANGER / FLANGING DEMYSTIFIED

[ForcedFire]

For your viewing pleasure: http://www.youtube.com/watch?v=jtb7B-o_xAY


Nathan

[~arph]

Mmm.. somehow it still sounds more like a chorus to me, and one that is only effective in a small range of the LFO swing.

The magnus modulus is brilliant though!
Here is an idea for you. As I've always liked the sweep echo on the DL4. To me it sounds like a modulated filter on the delays only. I've been experimenting with a modulated wah. Which works fine, but is definately not a very useable sound. So how about sticking a simple phaser in the delays?

Regards,

~arph

[Thomeeque]

For your viewing pleasure: http://www.youtube.com/watch?v=jtb7B-o_xAY


Nathan

Cool! This way you are getting even magical zero-point flanging, right?

Btw., technical note: I'd say, that there should be t-Δt at bottom branch at last pic as well, not Δt only..

[~arph]

Yes I guess it should do TZF. But there is always a delay of at least ~30ms with the pt2399. As that is the minimum amount of delay it can do.

[Thomeeque]

 Until time machine is invented, 100% real time TZF is impossible

Is lets say 50ms (to have some space for modulation) delay already annoying for real time playing?

[~arph]

well, if you'd be shredding 20 notes a second, your sound will be one note behind. 

[Thomeeque]

well, if you'd be shredding 20 notes a second, your sound will be one note behind. 

Definitely not my case - 20 seconds a note would be much closer 

[~arph]

Neither my case, but it should be on the box, right? 

[StephenGiles]

I'm just wondering if you need to lower the level of the LFO so that the sweep is not so wide.

[ForcedFire]

Hey guys,

I meant the clip as more of a proof of concept than displaying some amazing Flanger I had made. It sounds like crap right now. I just threw it together and it needs a LOT of work. The whole sweep thing is just a crappy LFO I stuck together. I'm going to add a through put so you can mix in the dry signal and the slightly delayed flanging.

As for the t / t-dt thing in the video, I realized it wasn't right but I don't care, I'm too lazy to make it again. I think it gets the point across.

[John Lyons]

Nathan
Overall I think it sounds good.
Once you work out the LFO sweep it should sound rally nice.
It does sound more towards the chorus end of things but...

John

[ForcedFire]

The chorus effect is from the amplitude of the LFO being too high, then the delay time changes more than it should so I've got a bit of chorus in the clip. The point is, you can actually get flanging. It's hard to tell from the clip I guess but it definitely flanges, try it out.

[Nitefly182]

Until time machine is invented, 100% real time TZF is impossible

Is lets say 50ms (to have some space for modulation) delay already annoying for real time playing?

I believe you can manage it by having the dry signal always delayed by a few ms or so so the lfo can sweep the delay time so it arrives before the dry and get TZF.

[ForcedFire]

Until time machine is invented, 100% real time TZF is impossible

Is lets say 50ms (to have some space for modulation) delay already annoying for real time playing?

I've just been going off the Harmony Central Flanger article, they say the delay line is around 1ms to 10ms.

How many ms does the LFO usually cause the delay line to vary?

I don't know if you need 50ms. If you can push it down as low as it goes, say between 30-35ms, you can have the parallel delay channel tuned to only a few ms away from the delayed throughput line. It might be hard to tune the LFO to only vary such a small delay time in the chip.

[doug deeper]

i think it sounds great as is, very much like tape flanging, not so much like pedal flangers.
well done!

[ForcedFire]

I just tried it with a new oscillator: http://www.youtube.com/watch?v=LKoZlFp8Ljw

Makes it way smoother. Still sounds a bit like a chorus but it definitely has flanging sweeps going on. I tried adding a regeneration feedback loop but haven't really perfected it yet. I've got to figure out all the scaling factors everywhere to try to get the effect to be more pronounced.

[John Lyons]

The sweep is definitely better spaced on the second clip, although the first clip has a cool detuned phased quality to it.
Sounding good! I'm sure once you get the feedback up a little it will become deeper and more lush.
Keep up the good work!

john

[Thomeeque]

I'm sure once you get the feedback up a little it will become deeper and more lush.

Unfortunately there's no any trick possible to get feedback delay under PT2399's minimum and this could be too much..?

So, guys, here's maybe general question : are you able to get your hands on PT2398 or PT2396 chips? Or there's only PT2399 available for you? Because those two allow "base" delay time of chip to be set (16 options) and the range is pretty wide, just check datasheets.. accidentally I'm developing CHORUS/FLANGER/(SHORT)DELAY effect based on PT2398 these days (that's why I'm so active in the ForcedFire's threads ), it's range is from 4.1 to 163ms (approx. half of 2399's max, because it has only 20Kbit memory). PT2396 would be best of both world's, because it allows both: very short times and even slightly longer times than 2399 (it has 48Kbit memory), but it requires external VCO for fine tuning and/or modulation plus I have not found supplier (but I did not try very hard - I'm planning to build pure DELAY pedal later with two 2399's for longer times).

EDIT:

Btw. http://filters.muziq.be/model/ibanez/soundtank/em5 uses M65831 chip, which is PT2396 functionally compatible with.

PT2396 d/s: http://www.princeton.com.tw/downloadprocess/downloadfile.asp?mydownload=PT2396.pdf

EDIT2:

You will need M65831 d/s for delay time table: http://www.datasheetarchive.com/pdf-datasheets/Datasheets-20/DSA-397998.pdf

[ForcedFire]

Hey Thomeeque,

That's why I'm posting here, I'm hoping someone else can come up with some ideas for how this'll work.

I think it's possible to get your hands on any delay chip really. The thing is PT2399 is readily available and used everywhere now. I like the idea of making projects with parts that are easy to find and relatively cheap. Small Bear does carry the 2395 and 2396. I'll have to pick some up.

The way I have it, the minimum delay of the chip just affects the delayed sound of the output. It's almost real time but not quite so I'll definitely be adding a real time signal mixed in a the output. Then the effect will almost sound like a flanged doubler which I think will be cool. So the throughput gets delayed by say 35 ms, then the delayed side gets delayed by say 38 ms, the relative delay is only 3 ms. When I add the feedback it's just on the slightly longer delayed side so it should work.

I think the LFO shape might be the first thing to really look at. I'm going to build a more complicated one so I can get different shapes and see what sounds best.

Anyone have a good LFO schematic with common value parts that can do different wave shapes? Otherwise, I guess I'll start from scratch.

[German]

And, why no-one is playing flanger demos with distortion? Flanger, like phaser sounds good, when you use a distortion before it.