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Placing Time-Based FX After Amp block


jcshirke
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Quick question: If you place time-based fx after the amp block, is it basically the same thing is putting those fx in an fx loop? So, for those real amps that lack an fx loop, doing so in the HX would essentially be acting as if they did have one.

 

I guess there is a follow-up question, too. I think I placed delay and reverb after the amp block, but before the cab block, and it sounded much better than placing the fx after the cab. If you have an amp/cab block that is combined, I assume you'd need to separate them into two blocks in order to place the fx in their proper place before the cab?

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1 minute ago, jcshirke said:

Quick question: If you place time-based fx after the amp block, is it basically the same thing is putting those fx in an fx loop? So, for those real amps that lack an fx loop, doing so in the HX would essentially be acting as if they did have one.

 

Not exactly. When using a typical FX loop, there's still an amplification circuit to follow, and depending on the kind of circuit, it might as well add some kind of dynamic and/or saturating behaviour, which, in return, would alter the sound of your FX unit, something that won't happen if you place things after the entire amp.

 

5 minutes ago, jcshirke said:

I think I placed delay and reverb after the amp block, but before the cab block, and it sounded much better than placing the fx after the cab.

 

Hm, this is unlikely to happen as there's no dynamic things happening in the cab block, it's a rather linear thing. Ok, there's a tiny amount of time based processing happening, too (especially in case you turn up early reflections), but that shouldn't be all too noticeable. You could create two paths with identical settings and just exchange the order of the blocks to crosscheck. Also, make sure to use mono blocks all throughout when checking.

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I put my time-based effects after the amp+speaker block.  In other words, I simulate studio delay after the mic'ed up amplifier/cab. 

 

I also use a parallel loop with a dummy block where I split the signal and mix it with the effects in parallel.  Just basically my unprocessed sound gets mixed with the delays in parallel due to the parallel loop that joins the main signal.  This allows the delays to sound less harsh and more musical, somehow. The main advantage is that if I have a stereo ping-pong delay, I will always have my initial note signal coming out of both left/right channels.  It's eliminates the extreme left/right mix that can be problematic at a large venue.  And to clarify, I have the ping-pong delay that is often timed to a song where I harmonize with my own delay'ed sound, and there is no way to have the main sound coming out of both sides, unless I do this trick.  Mixing your delays in parallel also affects the mix and the overall sound of your delay.  Even if the parallel loop is there and none of the blocks in the loop are engaged, the loop affect the overall mix.  If I remove the dummy block the overall mix becomes completely different.

 

Give the parallel loop a try!

 

Now where to place the time-based effects.... The cab block absolutely colors the sound.  For example, I will never put spring reverb after my cab, it will sound unnatural.  The effects loop of your amp is when you place your effects between the preamp and power amp.  Every power amp colors your sound.  Every speaker cab colors your sound.  So try and see what sounds more musical.  A processor will never work/sound exactly the same as the real gear, so you can always find some workarounds, as long as the end-result is good. 

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21 minutes ago, theElevators said:

The cab block absolutely colors the sound.  For example, I will never put spring reverb after my cab, it will sound unnatural.

 

Unless the spring reverb is doing some dynamic processing (which it shouldn't), that's unlikely.

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In case it wasn't clear, ITRW the amp's FX loop is between the preamp and the power amp, the idea being to not have the preamp coloring and amplifying the sound of the FX.

You can't do that with Helix.

That said, lots of people LIKE having the time based FX before the amp, among them David Gilmour and Joe Satriani. It's the way it was done before amps HAD FX Loops!

Also, on recordings, it's not uncommon to add reverb and delay in Post (after the cab).

The method @theElevatorssuggested is another way, although the MIX control accomplishes the same thing, it sounds better to him, and therefore it IS better!

I always run Reverb and Delay in parallel so that the delays aren't reverbed. To me, it sounds cleaner, less cluttered.

There's lots of ways to skin this cat. Try them all and use what works best for you.

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1 hour ago, rd2rk said:

In case it wasn't clear, ITRW the amp's FX loop is between the preamp and the power amp, the idea being to not have the preamp coloring and amplifying the sound of the FX.

You can't do that with Helix.

 

Right, but I was basically asking if putting the time-based fx after the amp, but before the cab amounted to the same thing--or at least close enough.

 

1 hour ago, rd2rk said:

That said, lots of people LIKE having the time based FX before the amp, among them David Gilmour and Joe Satriani. It's the way it was done before amps HAD FX Loops!

 

I know, but the sound does get muddy pretty quickly. EJ puts his delay before his Marshall, but he adds reverb by micing the amp and adding it in post.

 

1 hour ago, rd2rk said:

Try them all and use what works best for you.

I will certainly experiment. Thank you.

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11 minutes ago, jcshirke said:

Right, but I was basically asking if putting the time-based fx after the amp, but before the cab amounted to the same thing--or at least close enough.

 

 

It's as close as you can get with Helix, but not the same.

 

13 minutes ago, jcshirke said:

I know, but the sound does get muddy pretty quickly. EJ puts his delay before his Marshall, but he adds reverb by micing the amp and adding it in post.

 

 

IDK, I never thought of DG's or JS's sound as muddy, LIVE or recorded!

Like I said though, LOTS of ways to skin this cat. Have fun experimenting!

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2 hours ago, jcshirke said:

I know, but the sound does get muddy pretty quickly.

 

It all depends on how much drive your amp is delivering. With just a tad of saturation, it often helps to sort of "tame" delays or "gel" them together. Doesn't work too well on heavier driven amps anymore, though.

Fwiw, the same goes for modulation FX. I usually love them a lot more in front of a slightly driven amp.

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9 hours ago, SaschaFranck said:

Well, turns out I was right. There's no difference between rev->cab and cab->rev when using the Hot Springs reverb in mono. Compared two otherwise identical bounced files and they pretty much cancel out each other in a null test.

 

It all depends on the "high end" produced by the effect. If the highs are all natural (nothing actually added) then I agree with you.... 

But If the effect adds artificial high end to the tone.... 

  • The highs are retained when after the cab block
  • The high are attenuated by the cab block when it is between amp & cab (when the highs extend beyond the frequency of the speaker/cab)

 

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7 hours ago, codamedia said:

It all depends on the "high end" produced by the effect.

 

Sorry but no. It all depends on whether it's either a non-linear or timebased (or modulating - but that's pretty much timebased, too) effect.

With non-linear effects, the order is pretty important. Example: two different drive blocks will sound fundamentally different in A->B or B->A order.

With time based effects, most often the order is pretty noticeable. Example: A reverbed delay sounds different from a delayed reverb. Same goes for two different delays or reverbs in series.

The high end however is completely irrelevant in this equation. Two EQs in series will sound 100% identical, regardless of their settings. As a result, in a serial chain of linear effects (and non-dynamic delays and reverbs are linear effects) you can place an EQ anywhere you like - and the cab block in this example does serve merely as an EQ block.

 

Now - and I've said so already: Once you push the timebased portion of a cab block a bit more, things will get more noticeable. Obviously, you can do so by dialing in some early reflections. In this case, the cab block also acts like a "mini reverb/delay" (in addition to the EQ duties) and as a result of that, the order will become slightly more important - I doubt anyone would be able to tell just by their ears, though (I would happily supply some audio examples, in case someone wants to check).

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18 minutes ago, codamedia said:

Why am I not surprised by this ... LOL! 

 

What's so funny about it that you need to laugh out loud? Your statement was incorrect and it's just fair game to point out incorrect statements. As easy as that.

But hey, how comes I knew you'd make something out of it? Sure, Mr. Franck is just an evil guy. Well, be it so. Your statement is still wrong.

 

Edit: Feel free to explain what you were refering to when saying "adding unnatural highs". Ideally along with an example of a HX series reverb that is doing so.

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26 minutes ago, SaschaFranck said:

Your statement was incorrect and it's just fair game to point out incorrect statements.

 

My statement is not incorrect. A CAB or IR has a natural attenuation in high end... that attenuation will effect any effect that is before it - providing that effect is creating more high end than it's been fed. Some do, some don't. That's all I'm stating. 

 

26 minutes ago, SaschaFranck said:

Feel free to explain what you were referring to when saying "adding unnatural highs". Ideally along with an example of a HX series reverb that is doing so.

 

I never said reverb, I said "effects that add artificial high end". I am not limiting it to just reverb. 

 

Easy test:  Princess Amp > 112 US Deluxe Cab

Put a mono "pitch echo" before the cab, then move it after the cab. It's very different. 

 

The high end sizzles on that delay when it's after the cab, not so much when it's before the cab. 

 

If you really want to accentuate the difference, increase the high cut on the cabinet (ie: make the high cut more noticeable by lowering the frequency) and continue the test.

 

On 10/4/2021 at 9:01 AM, SaschaFranck said:

Well, turns out I was right. There's no difference between rev->cab and cab->rev when using the Hot Springs reverb in mono. Compared two otherwise identical bounced files and they pretty much cancel out each other in a null test.

 

For the record... if there is ANY residual sound after a null test, then the files are not identical. There is a difference whether your ears notice or not. 

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24 minutes ago, codamedia said:

Put a mono "pitch echo" before the cab, then move it after the cab. It's very different. 

 

Sure. So what? That's an effect highly varying depending on the input signal (mainly because it's a rather bad algorithm that works a lot better with some frequencies and pretty bad with other frequencies). For any standard delay/verb, this is not the case.

26 minutes ago, codamedia said:

For the record... if there is ANY residual sound after a null test, then the files are not identical. There is a difference whether your ears notice or not. 

 

The differences are so small no human being would notice them at all (we're talking about something like -50dB and it's only artefacts left anyway). If you don't believe it, I'll set up a testfile so could tell me where you spot a difference. You could of course just try for yourself.

28 minutes ago, codamedia said:

A CAB or IR has a natural attenuation in high end... that attenuation will effect any effect that is before it

 

Still no. There's exceptions, such as FX not dealing well with certain frequencies (such as the pitch echo) and with cabs it's a larger difference once you turn up early reflections (which follows same principle as reverbs and delays running in series to sound different if you exchange their order). But others than that, there's absolutely no audible differences in case you run a typical cab IR and a typical (non-dynamic) delay/verb in either A/B or B/A fashion. Once you replace the cab with an EQ, the results will even perfectly null out.

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9 hours ago, SaschaFranck said:

 

Hm, that'd be a weird sound. A totally clean DI guitar with delay and reverb, mixed with a dry amped guitar. But ok, why not...

 

The OP was asking about emulating an F/X loop with a guitar amp that didn't actually have an F/X loop.  I figured this might be a viable option seeing as no matter what you do everything is hitting the front end of the amp.  It's just a guess on my part but I think maybe this might be the closest thing there is to 4CM sound on a non-loop amp.

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3 hours ago, MGW-Alberta said:

The OP was asking about emulating an F/X loop with a guitar amp that didn't actually have an F/X loop.

 

Exactly. And the closest you could get within the Helix without dedicated power amp models available would be to place your typical loop FX between amp and cab.

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2 hours ago, SaschaFranck said:

 

Exactly. And the closest you could get within the Helix without dedicated power amp models available would be to place your typical loop FX between amp and cab.

You're right.   I overlooked that.   I assume you meant the return and not the whole loop.  

It should look like this:

 

51556910091_9880971d02_b.jpg

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36 minutes ago, MGW-Alberta said:

You're right.   I overlooked that.   I assume you meant the return and not the whole loop.  

It should look like this:

 

51556910091_9880971d02_b.jpg

 

Well, not really. That would still send a DI guitar signal into the FX, without any amp signal.

It should rather look like this, in case you wanted to get as close as possibleimageproxy.php?img=&key=183b093d1325c787 to a real amp FX loop:

Loop.jpg.288293c9d1fd7a428ed1e30cd67df1d6.jpg

 

But unless you wanted to do some rather special tricks (such as running just the delayed signal into the reverb, which would require a 100% wet delay), you could as well just place the delay/reverb blocks inbetween the amp and cab blocks, saving path B for other purposes.

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6 hours ago, SaschaFranck said:

 

That would still send a DI guitar signal into the FX, without any amp signal.

 

Yes.  You're right.  It does.

Remember the Helix output is going into an amplifier.
An amp without a loop.

And we're trying to emulate an amp with a loop, where the time stuff doesn't mix with the dirty stuff until the very end.

 

But thanks for the heads up about the cab.    That was a good catch.

 

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Sorry for reviving this, but fwiw, for those interested in a bit more than just anecdotal evidence regarding FX order, here's a pretty good read. Explains some of the things I tried to explain much better than I ever could:
https://moinsound.wordpress.com/2015/01/30/audio-engineering-myths-linearity/

 

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