Keeley Halo

guitarnerdswe

Fractal Fanatic
EDIT: Thanks to all the users in this thread like @Burgs, @Blix, @AlbertA, @Jesse, @Bakerman etc, who gave me tips and ideas to improve this further.

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I actually did a deep dive into ATs delays a while back when he was using the Timeline, and found "the trick" that I can't recall seeing anyone do in their AT presets (forgive me if I missed it). For some reason, I never shared the info, but better late than never right?

The Halo mode of the Keeley Halo is basically the same thing as what he was doing with his Timeline: 2 stereo delays in series, and each delay has the same times for left and right. One has the dotted eight on both sides, and the other has a quarter note on both sides. So they're essentially mono delays at this point (even though they are hard panned stereo delays).

So "mono", UNTIL: You introduce modulation. You can hear this in the official Keeley video for the Halo. As soon as they remove the modulation, the delays "collapse" to mono. Same thing happens on the Timeline. The modulation is different for left and right (LFO phase offset), and that's what makes it stereo and spreads it out. The phase of the quarter note is also inverted, for some reason. It actually does nothing for the stereo spread. Delay times are 360/480 ms. It uses a tilt EQ outside of the feedback loop, which is kind of unique. This means that the repeats don't degrade over time.

The only way to do it on the Axe-Fx, is with 2 stereo delays, plus a filter block. The dual delay type, quad delay variants etc, don't have the necessary architecture and signal flow to make this happen.

I used the clips from @Scented Meat Halo pedal as a reference (I hope it's ok?). First Halo, then Axe-Fx.



I've attached the preset below, which is just the factory Cliffs of Dover preset but with the Halo delay setup added. Feel free to lower the level of the delays, since they're quite high in the mix.
 

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  • Keeley Halo v2.1.syx
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The only way to do it on the Axe-Fx, is with 2 stereo delay blocks in series. The dual delay type, quad delay variants etc, don't have the necessary architecture and signal flow to make this happen.
You sure the MTD or 10 Tap can't handle this? I'm pretty sure either could. I'll have a go at it...

Yours sounds dead to nuts though. Nice job.
 
You sure the MTD or 10 Tap can't handle this? I'm pretty sure either could. I'll have a go at it...

Yours sounds dead to nuts though. Nice job.
I've tried many times before, as recently as earlier today. Since they aren't individual delays, but rather mono taps, the way they interact is completely different. They also don't respond to modulation in the same way (they don't support stereo modulation for the individual delay taps).
 
Wow good job!

What was it about the dual delay that you couldn't make it work?
They're missing all the needed internal stereo connectivity (cross feedback is mono) and stereo modulation.

There is no way to create the slight offset of a few ms between left and right that stereo modulation does, since they only use the main outputs from the mod LFOs. The secondary LFO outputs (the parameters called "phase" under the mod tab) don't do anything. Assigning a LFO to left or right doesn't do anything either.

So in essence, dual delays are just mono delays with cross feedback. True stereo needs discrete left and right at every stage of the signal flow, and the Halo needs two complete instances of that to work.
 
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Really looking forward to checking these blocks out, thanks! I knew that what I came up with using Dual Delay and cross feedback was “wrong” but it sounded a lot better than anything else I could come up with. The modulation was clearly not right and that’s what I kept playing with. I even tried putting a chorus after the delay which I liked the sound of but still wasn’t totally there.
 
The Halo mode of the Keeley Halo is basically the same thing as what he was doing with his Timeline: 2 stereo delays in series, and each delay has the same times for left and right. One has the dotted eight on both sides, and the other has a quarter note on both sides. So they're essentially mono delays at this point (even though they are hard panned stereo delays).

So "mono", UNTIL: You introduce modulation. You can hear this in the official Keeley video for the Halo. As soon as they remove the modulation, the delays "collapse" to mono. Same thing happens on the Timeline. The modulation is different for left and right (LFO phase offset), and that's what makes it stereo and spreads it out. The phase of the quarter note is also inverted, for some reason. It actually does nothing for the stereo spread. Delay times are 360/480 ms.
So first I have to say these are amazingly good, way better than what I came up with. Have a couple questions/comments if you don't mind indulging me.

Just re-watched the Keeley video and he says that the modulation cross fades between the two channels. Is that what's happening in your blocks? Both the first and second delay block have LFO1 set to target Both with a phase of 90 deg. Would you not want to use both LFO 1 and LFO 2 with each targeting a different channel and a 90 degree phase shift between them?

Regarding diffusion, I feel like this gets mentioned in passing on some of the Halo videos. I liked the sound of a small amount of diffusion with Diffusion Time around 70% and a bit of modulation. The blocks guide says that adding modulation to the duffuser gives a chorus-like effect, which Andy mentions in the Keeley video.

Last is just a comment that I liked the EQ settings you used much better than what I had. I was using a Memory Man like EQ curve with a sharp roll off. I was finding it difficult to make the first delay repeat sit correctly in the mix. You used the 6 dB slopes which are the default on the tape delays. Any idea if the actual pedal is doing something similar?

EDIT: threw this on a patch with a few different variations. I dialed this in in a Strat, neck pickup with the volume rolled off a bit. Scene 1 is the blocks just as above except mix turned up. Scene 2 used LFO1 and 2 as described above. Scene 3 adds a bit of diffusion with modulation to the mix.
 

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  • JN Andy's Halo 2.syx
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The dual delay is type 2 mono delays. So they're missing all the stereo in/out (cross feedback is mono) and stereo modulation. There is no way to create the slight offset of a few ms between left and right that stereo modulation does.
Well, dual delay is still a stereo delay - just with added cross feedback - so it can do stereo modulation still

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Also since you really only use one LFO in each delay block, you could use LFO1 and LFO2 in a dual delay block to approximate - though at the moment, we wouldn't be able to replicate the same LFO phase arrangement you have (which is 1/8dot 0 for L, 90 for Right and 1/4 delay 0 left, 90 for right) (if we had a switch that said phase control applies to L or R we could do it).

You would also need to account for the ratio of the 1/8 dot delay level to the 1/4 delay, but that could be controlled with the FeedBack L-R level.
But yeah it wouldn't be quite the same stereo arrangement in the end.


In any case, great work!


From what I recall after talking to Keely, I think they have a third LFO modulating the phase (there was some mention about maybe a 6-stage LFO). We could probably just attach a modifier to the Phase control in the delay blocks and modulate around around 90
 
So first I have to say these are amazingly good, way better than what I came up with. Have a couple questions/comments if you don't mind indulging me.

Just re-watched the Keeley video and he says that the modulation cross fades between the two channels. Is that what's happening in your blocks? Both the first and second delay block have LFO1 set to target Both with a phase of 90 deg. Would you not want to use both LFO 1 and LFO 2 with each targeting a different channel and a 90 degree phase shift between them?

Phase of 90 in a stereo delay means that the LFO when applied to the right channel delay is 90 degrees out of phase, both left and right are still modulated.

Regarding diffusion, I feel like this gets mentioned in passing on some of the Halo videos. I liked the sound of a small amount of diffusion with Diffusion Time around 70% and a bit of modulation. The blocks guide says that adding modulation to the duffuser gives a chorus-like effect, which Andy mentions in the Keeley video.
at least from what I could gather after talking to keely they don’t use diffusion in the halo pedal.
 
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You’re not helping my GAS with that new Charvel Brett. Those SSL-6’s are a perfect match with the JB.
Yeah, those guitars are pretty bare bones, but they're the right bones for my needs. I'll be taking this one and its sassafras brother out when touring starts again. Well worth the quite reasonable coin, I think!
Great video!

Maybe using the compander and perhaps modulating the phase parameter in the LFos may get it closer.
Thanks! I will try both of those approaches. Cheers.
 
Here's a slightly different take on it. I've used Stereo Memory Man blocks instead of Stereo Tape Echo. I've applied most of @guitarnerdswe's settings where applicable and tweaked anything else to ear. The end result isn't miles away from @guitarnerdswe's version but to my ears sounds a little warmer. I'm pretty sure I remember Robert telling me early on, during the HALO's final prototype stage, that the Memory Man was involved, hence my attempt here. But before @guitarnerdswe's amazing work, I was trying to replicate the HALO with a single block, and gave up. But now... 😅

Anyway, string these together and see what you think. The preset is here as well. Memory Men on Scene 3. You'll need your own HALO to complete Scene 1.

I can make another video if you think it's worth it.
 

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  • HALO vs Delay Blocks (v2).syx
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I have my Halo in a loop so I can quickly A/B.

Pretty close, but not identical, the repeats fades into "darkness" faster and more abrupt than the pedal, so you don't get the same reverb-y effect as from the pedal.

But definitely the closest I've heard so far.
 
Well, dual delay is still a stereo delay - just with added cross feedback - so it can do stereo modulation still
I think the issue here is that the Dual Delay is defining one delay time as either the L or R channel. The cross feedback ends up feeding back into the dotted 1/8th, which isn't what happens in the real pedal (or the old Memory Man setup). There was "too much" going on there, which is I think why I started throwing diffusion at it.
Phase of 90 in a stereo delay means that the Lego when applied to the right channel delay is 90 degrees out of phase, both left and right are still modulated.


at least from what I could gather after talking to keely they don’t use diffusion in the halo pedal.
Not that I'm doubting what you're saying, but do you have more info on how the phase offsets work? I've found that things like the Blocks Guide and the Wiki tend to be pretty short on technical details, especially on more advanced parameters like this. The way I was interpreting this, it is applying a 90 phase offset to "both" channels. You're saying that there's an additional 90 already baked in there on the R channel? To my ears at least, when I set LFO1 at 90 deg targeting L and LFO2 at 180 deg targeting R, I heard a much wider sound.

Re: diffusion...after using the stereo blocks in series, I no longer felt the diffusion sounded right. I think it was just a Band-Aid I was using on a poor solution.
 
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