nomad100hd
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the way i see it at least with a series loop you can build a box with to do the parallel part. My tone got better once i modded for series, but eventually i will put a switch in for a little of both.
EQ in Loop of Dual Recto..and how is you recto EQ'ed?
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Chris McKinley
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tetsubin,
RE: "Your theory will have to change when one puts multiple analog pedals in a loop.". It still doesn't typically change, since even 3 or 4 analog circuits in a row are usually not long enough in circuit length nor do they contain enough cumulative resistance to produce a noticeable lag in sound.
RE: "But I do not mean setting the loop to 100% wet. I mean setting the fx to 100% wet, so that no unaffected signal passes through.". I know that's what you meant, but your statement is incorrect. Even setting an effect to 100% wet will not result in hearing only 100% affected signal, since there is still the hard minimum of at least 10% signal that never even passes through the effect loop, regardless of whether the effect is digital or analog, or whether or not you set the mix to 100% wet. You still don't get a 100% affected signal and you still don't prevent phase discrepancy from occurring. The unaffected portion of the signal will still produce sound faster than whatever mix of signal is coming through the effects loop, and this is what causes phase discrepancy.
Even in digital effects, it is the discrepancy between the effects loop signal and the minimum 10% unaffected signal that produces the audible phase noise, not the internal discrepancy of the digital unit itself between the 'wet' and 'dry' signal that passes through the unit's circuitry. Therefore, simply setting the effect (whether digital or analog) to 100% wet mix will not remedy any audible phase noise. This is precisely what Peter Diezel is warning of in the last statement you quoted of his.
Peter's admonition, however, will only prove a workable solution to the problem if you have a parallel loop that allows for full, 100% wet signal. If that's what you had, then setting the effect to 100% wet, and also setting the mix on the parallel loop to 100% wet would get rid of phase discrepancies, but it would also limit you to 100% wet signal all the time. You see, Peter's notes do not take into account the fact that, unlike some parallel loops, Mesa's parallel loop does not allow for 100% wet signal, therefore he accounts only for the possibility of phase discrepancy internal to a given effect unit, and not for the far more relevant phase discrepancy between the net signal from the loop and the completely unaffected signal in the amp.
I can see how you might have come to the conclusion you did if you assumed that Peter had taken Mesa's 90/10 version of a parallel loop into account. However, even in a 100/0 parallel loop, Peter's solution still doesn't solve the real problem of loop/non-loop discrepancy.
I have already stated the bottom line is about perceptible, audible phase discrepancy. As many on this board have learned through direct personal experience, most digital effects run through Mesa's 90/10 parallel loop typically cause noticeable to intolerable phase noise, regardless of how the mix on the effect is set, and analog effects typically do not. At the end of the day, it's really as simple as that.
RE: "Your theory will have to change when one puts multiple analog pedals in a loop.". It still doesn't typically change, since even 3 or 4 analog circuits in a row are usually not long enough in circuit length nor do they contain enough cumulative resistance to produce a noticeable lag in sound.
RE: "But I do not mean setting the loop to 100% wet. I mean setting the fx to 100% wet, so that no unaffected signal passes through.". I know that's what you meant, but your statement is incorrect. Even setting an effect to 100% wet will not result in hearing only 100% affected signal, since there is still the hard minimum of at least 10% signal that never even passes through the effect loop, regardless of whether the effect is digital or analog, or whether or not you set the mix to 100% wet. You still don't get a 100% affected signal and you still don't prevent phase discrepancy from occurring. The unaffected portion of the signal will still produce sound faster than whatever mix of signal is coming through the effects loop, and this is what causes phase discrepancy.
Even in digital effects, it is the discrepancy between the effects loop signal and the minimum 10% unaffected signal that produces the audible phase noise, not the internal discrepancy of the digital unit itself between the 'wet' and 'dry' signal that passes through the unit's circuitry. Therefore, simply setting the effect (whether digital or analog) to 100% wet mix will not remedy any audible phase noise. This is precisely what Peter Diezel is warning of in the last statement you quoted of his.
Peter's admonition, however, will only prove a workable solution to the problem if you have a parallel loop that allows for full, 100% wet signal. If that's what you had, then setting the effect to 100% wet, and also setting the mix on the parallel loop to 100% wet would get rid of phase discrepancies, but it would also limit you to 100% wet signal all the time. You see, Peter's notes do not take into account the fact that, unlike some parallel loops, Mesa's parallel loop does not allow for 100% wet signal, therefore he accounts only for the possibility of phase discrepancy internal to a given effect unit, and not for the far more relevant phase discrepancy between the net signal from the loop and the completely unaffected signal in the amp.
I can see how you might have come to the conclusion you did if you assumed that Peter had taken Mesa's 90/10 version of a parallel loop into account. However, even in a 100/0 parallel loop, Peter's solution still doesn't solve the real problem of loop/non-loop discrepancy.
I have already stated the bottom line is about perceptible, audible phase discrepancy. As many on this board have learned through direct personal experience, most digital effects run through Mesa's 90/10 parallel loop typically cause noticeable to intolerable phase noise, regardless of how the mix on the effect is set, and analog effects typically do not. At the end of the day, it's really as simple as that.
Chris McKinley said:
This is the point to which it comes down. I agree, that in the end it's all about taste (not even phasing issues, as most people don't care about what makes their sound how it is).
But still, you don't get what Peter Diezel is saying.
To show what you're not getting I will quote you: "Even setting an effect to 100% wet will not result in hearing only 100% affected signal, since there is still the hard minimum of at least 10% signal that never even passes through the effect loop [...]"
You would be right if that was my point, but as I said, you didn't get what Peter Diezel and any other amp manufacturer will tell you.
I think I'll give an example to make it clear, once and for all (and please re-read my last post and perhaps just start to rethink all this, as you're caught in the same pattern):
1. We have a parallel loop: a) internal b) send-return
2. We take Digital Delay that can be set to 100% wet (Behringer DD400). The Outputs just give me the delayed signal. (The G-Major calls this the "Kill Dry" function.)
3. We place the effect in the loop, which we set to, say, 20% mix.
So, let's resume what's happening now:
4. In 1a (the internal signal path) there's just the unaffected signal.
5. In 1b (the send-return/fx path) there's no unaffected signal passed through, because the fx is set to "kill dry", 100% wet, or whatever you'll call it. There is absolutely no unaffected signal coming through.
Ok, let me quote you again (same quote): "Even setting an effect to 100% wet will not result in hearing only 100% affected signal."
Right! But that would be a completely stupid idea anyway: just hearing the delays? Come on! Ok so this point is not what it's all about.
Ok, I'll continue the quote: "[...] since there is still the hard minimum of at least 10% signal that never even passes through the effect loop"
And that's your problem: you're still thinking it's about setting the loop-mix to 90% or so. And it's not.
Remember, in step 2 and 3 we set the fx to 100% wet (kill dry)(and that is a real option, no unaffected signal passes through!) and take 20% of it to mix with the unaffected signal.
So let's get to
6. The affected signal in 1b is getting mixed (at whatever percentage you like!) with the unaffected signal.
7. Result: No phasing issues, because there is no time-delay of an unaffected signal added to the same unaffected signal. It's just an affected signal that gets added to the unaffected signal. In this case it's delayed.
So, that is the point. And even your last post was still a bit confused.
For example you misread Diezel's statement to make it match your pattern of thought:
"Peter's admonition, however, will only prove a workable solution to the problem if you have a parallel loop that allows for full, 100% wet signal."
That is plain wrong.
I quote Peter again: "Important: You must set the mix control on the effects unit to 100% wet when using the parallel loop. Otherwise there will be nasty phasing problems resulting in unsatisfactory tone. The signal portion that is unaffected by the mix control in the effects unit would reach the amplifier at a different time due to the cabling, and cause phasing cancellations."
He is talking about what I'm talking about: Setting the mix control on the effects unit to 100% wet.
That's the whole magic and that's the point that invalidates your whole argument. It's not about the internal loop which passes unaffected signal, of course it does, that's what it's supposed to do. It's the other way round: you got to eliminate unaffected signal from the send-return-path!
Please rethink this, as I don't have too much time to answer the same arguments again and again. And hey, if there's someone smarter in the room, why not acknowledge it and learn from him? Because that's what I've done. (Before having read Peter Diezel's explanation I was confused like you. My posts actually just consist of making clear what Peter wrote.) Making mistakes is no shame at all, but clinging to them is what I hate.
Chris McKinley
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tetsubin,
At this point, I believe it would seem clear that you perhaps simply do not have much if any experience actually running a variety of both digital and analog effects, singly and in multiples, through the parallel loop of a Mesa amplifier. Perhaps that is an incorrect assessment, but your continued statements and claims simply are not in accord with the experiences of the rest of us who have. Not a personal statement, just an evaluation of your argument.
Without getting into legalese of Section A,B,C...Subparagraph X,Y,Z any more than you have already introduced, let me just cut right to the chase with your number 7, since it is on this point where you are repeatedly, and at this point insistently, wrong.
For clarity, you stated, "7. Result: No phasing issues, because there is no time-delay of an unaffected signal added to the same unaffected signal. It's just an affected signal that gets added to the unaffected signal. In this case it's delayed.". This statement is simply inaccurate. It is in the discrepancy between the affected signal in the loop (your 1b) and the unaffected signal in the amp (your 1a) where all of the audible phase noise due to phase discrepancy occurs. All of it.
There is no audible phase noise that occurs internally to an effect in the loop between its affected portion of the signal and its unaffected portion. This is because, in both digital and analog effects, both portions of signal leave the unit at too nearly simultaneously to produce audible phase noise. IOW, the wet and the dry portions of the signal leave the unit so close to the same time that they do not produce enough phase discrepancy to be heard by the human ear. Both portions of signal in an analog unit (the wet and the dry) also leave the unit much quicker than in a digital unit, since the analog circuit pathway is so much shorter, even in true bypass units.
In digital units, once again both the wet and the dry portions of the signal still leave the unit nearly simultaneously. In fact, the discrepancy is far lower than in analog units, since even the dry portion of the signal is entirely digitized and, in most digital units, the so-called dry signal is buffered so that is can be synchronized with the wet portion of the signal before they are both converted back to analog to leave the unit.
Now, while both types of effects, analog and digital, share the fact that their wet and dry signal portions leave the unit simultaneously enough not to cause audible phase discrepancy (and it is this fact that both you and Peter have thus far ignored), only the digital unit still provides enough net lag of the combined wet/dry signal from the unit to cause audible phase discrepancy with the signal internal to the amp which never entered the effects loop (your 1a).
Once again, in the interests of clarity, it is that discrepancy (between 1a and 1b), not any discrepancy internal to any kind of effects unit (whether analog or digital), that causes all audible phase discrepancy noise. Once again, this noise ranges from mild white noise to a sine wave siren whine depending upon just how large the discrepancy between 1a and 1b is, which is itself determined by how much lag a given effect produces dependent upon its circuit length and total circuit resistance.
Therefore, your solution of ignoring 1a/1b phase discrepancy and merely setting the effect mix to 100% is no solution at all, since even the 100% wet signal from the unit (in this case, 1b) experiences enough lag to produce audible phase discrepancy with the unaffected signal internal to the amp (your 1a).
It is the paragraph in bold above that most succinctly sums up the entire problem of effects phase noise in Mesa's parallel loop. Since nothing further, of a technical nature, remains unexplored and undiscussed, I will consider the matter closed, at least regarding any objective technical aspects.
At this point, I believe it would seem clear that you perhaps simply do not have much if any experience actually running a variety of both digital and analog effects, singly and in multiples, through the parallel loop of a Mesa amplifier. Perhaps that is an incorrect assessment, but your continued statements and claims simply are not in accord with the experiences of the rest of us who have. Not a personal statement, just an evaluation of your argument.
Without getting into legalese of Section A,B,C...Subparagraph X,Y,Z any more than you have already introduced, let me just cut right to the chase with your number 7, since it is on this point where you are repeatedly, and at this point insistently, wrong.
For clarity, you stated, "7. Result: No phasing issues, because there is no time-delay of an unaffected signal added to the same unaffected signal. It's just an affected signal that gets added to the unaffected signal. In this case it's delayed.". This statement is simply inaccurate. It is in the discrepancy between the affected signal in the loop (your 1b) and the unaffected signal in the amp (your 1a) where all of the audible phase noise due to phase discrepancy occurs. All of it.
There is no audible phase noise that occurs internally to an effect in the loop between its affected portion of the signal and its unaffected portion. This is because, in both digital and analog effects, both portions of signal leave the unit at too nearly simultaneously to produce audible phase noise. IOW, the wet and the dry portions of the signal leave the unit so close to the same time that they do not produce enough phase discrepancy to be heard by the human ear. Both portions of signal in an analog unit (the wet and the dry) also leave the unit much quicker than in a digital unit, since the analog circuit pathway is so much shorter, even in true bypass units.
In digital units, once again both the wet and the dry portions of the signal still leave the unit nearly simultaneously. In fact, the discrepancy is far lower than in analog units, since even the dry portion of the signal is entirely digitized and, in most digital units, the so-called dry signal is buffered so that is can be synchronized with the wet portion of the signal before they are both converted back to analog to leave the unit.
Now, while both types of effects, analog and digital, share the fact that their wet and dry signal portions leave the unit simultaneously enough not to cause audible phase discrepancy (and it is this fact that both you and Peter have thus far ignored), only the digital unit still provides enough net lag of the combined wet/dry signal from the unit to cause audible phase discrepancy with the signal internal to the amp which never entered the effects loop (your 1a).
Once again, in the interests of clarity, it is that discrepancy (between 1a and 1b), not any discrepancy internal to any kind of effects unit (whether analog or digital), that causes all audible phase discrepancy noise. Once again, this noise ranges from mild white noise to a sine wave siren whine depending upon just how large the discrepancy between 1a and 1b is, which is itself determined by how much lag a given effect produces dependent upon its circuit length and total circuit resistance.
Therefore, your solution of ignoring 1a/1b phase discrepancy and merely setting the effect mix to 100% is no solution at all, since even the 100% wet signal from the unit (in this case, 1b) experiences enough lag to produce audible phase discrepancy with the unaffected signal internal to the amp (your 1a).
It is the paragraph in bold above that most succinctly sums up the entire problem of effects phase noise in Mesa's parallel loop. Since nothing further, of a technical nature, remains unexplored and undiscussed, I will consider the matter closed, at least regarding any objective technical aspects.
Chris McKinley said:
Ok, Chris, I think we're narrowing down this argument
I agree with the above statement. But the manual of the Diezel is not flawed.
The thing is, there is no unaffected signal fed back into the return, so there are no phasing discrepancies. The milliseconds the 1b takes longer don't necessary result in phase discrepancies. Just, and that's the premise you always make, when any unaffected signal is fed back into the return. That's why Peter Diezel says to turn it to 100% wet.
Can you agree with the following paragraph?
What really happens when there's just the affected signal is this: imagine you have a song on your drum computer with a certain speed (BPM); you sat at home and calculated the correct milliseconds needed for a triplet-eighth-delay. Then you put a digital delay in the parallel loop.
What will you notice? There will be no phasing issues. BUT: The delay which ist set to, say, 100ms will come at, say, 101 ms. And that is the time the send-return (1b) takes longer than the internal path (1a).
----
So: I agree with you and I don't. Yes, the discrepancy between 1a and 1b is there. No, it will not necessarily result in phase discrepancies with a digital time-based fx (delay, chorus, flanger etc.) set to 100%.
That's the whole reason why I first replied: You simply can't put it in the digital vs. analog scheme. It doesn't work.
For example my Behringer DD400 (and probably ever other Boss digital delay pedal) works flawless in the parallel loop - if you set it up as described. I read about people having problems with pedals in parallel loops, but most of them don't have a clue how to set them up. And some pedals simply just don't belong there.
P.S.: And if you read Peter Diezel's VH4 manual it explicitly states that you can minimize tone loss from A/D and D/A conversion by using the parallel loop the way described. If you want to tell him that's wrong, please mail him and post his reply.
I think he's constructed quite a few top-notch amps in his life and knows what he's talking about.Chris McKinley
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tetsubin,
RE: "Can you agree with the following paragraph?". No, because that's not what happens. How much experience do you actually have working with either digital and/or analog effects? At this point, I have to ask because each time you describe a hypothetical situation, it has been invariably incorrect with respect to what actually happens.
The paragraph you asked me to agree with is yet another example, unfortunately. Since you have continued the discussion in a sincere manner, I shall try to explain point by point.
In the paragraph you described, there will, in all likelihood, indeed be phasing issues, and typically much larger than 1 millisecond as you described. Also, whether or not phase discrepancies will occur has nothing to do with whether or not the kind of digital effect used is delay-based or something else. For example, let's say a digital multi-effect unit is used in a Mesa parallel loop which has options for distortion/overdrive effects, short-delay effects (i.e., flanger, phaser, chorus), longer-delay effects (echo, delay), and reverb. Each of those effects, or any combination of them, is equally likely to produce phase noise since it is not the type of effect used but the output lag of the digital unit as a whole which is long enough to cause phase noise.
IOW, let's say you set the unit to produce a distortion effect rather than a time-based effect. A signal is sent through the amp's Send output into the unit, where the analog signal is converted to digital. Let's say you set the internal mix of the unit to 50% wet/50% dry. The wet signal then travels an (compared to analog) enormous circuit pathway through which the distortion effect is produced. The dry signal travels a somewhat shorter pathway, but is gated and buffered by the unit's internal circuitry. After processing, the unit's internal buffers synchronize both the wet and dry portions of the signal. The now-synchronized and combined 50% wet/50% dry signal is re-converted to a single analog signal.
However, because this entire process has taken a relatively much longer time to occur than it would through an analog counterpart, the final now-analog single signal (that contains both the wet and dry portions combined) enters the amp's Return input with typically a 20-50 (sometimes far more, depending on the unit) millisecond lag compared with the unaffected signal (that is, the signal that travelled only through the amp's circuitry. This lag is enough to produce noticeable white noise, and if the lag is long enough, a sine wave whine.
It is important to note that, regardless of how the mix is set on the digital unit itself, there is still only a single signal that leaves the unit. Once that signal enters the amp's Return input, there are still only a total of two signals: one which has travelled only through the amp and is therefore unaffected, and one which has travelled through the loop and the digital unit which, regardless of how the mix is set, is always an affected signal since it has been converted to digital and back again and been delayed by the unit's internal buffers. There is no such thing as an unaffected signal from the effects loop when a digital effect is used.
As to Peter, I have no desire to bother him (or anyone else not posting to this thread). If you wish to include him, you will have to do so yourself. However, were he involved here, I would state nothing different to him than I have to you. If Peter (or anyone else) were of a mind to claim that phase discrepancy does not occur between the output of a digital effect and a Mesa amp's internal circuitry, and instead occurs between the wet and dry portions of signal internal to the digital unit itself, the onus would be on him to provide evidence for that claim. Given that the opposite is easily demonstrable, and also fits everything we'd expect from electronics and what we know about the internal processing circuitry of digital effects, a person making such a claim would have quite the task ahead of him.
Despite the appeal to authority in the case of Peter Diezel, there is still not sufficient reason for anyone to be convinced by your argument, especially in the face of what is nearly overwhelming experience by anyone who has ever tried to use digital effects in the parallel loop of a Mesa amplifier. It is not even entirely clear at this point if you and Peter would be entirely in accord if Peter were here to state his views in person, especially if he were aware that we are not discussing typical parallel loops, but Mesa's specific variant which never allows for complete avoidance of phase discrepancy.
RE: "Can you agree with the following paragraph?". No, because that's not what happens. How much experience do you actually have working with either digital and/or analog effects? At this point, I have to ask because each time you describe a hypothetical situation, it has been invariably incorrect with respect to what actually happens.
The paragraph you asked me to agree with is yet another example, unfortunately. Since you have continued the discussion in a sincere manner, I shall try to explain point by point.
In the paragraph you described, there will, in all likelihood, indeed be phasing issues, and typically much larger than 1 millisecond as you described. Also, whether or not phase discrepancies will occur has nothing to do with whether or not the kind of digital effect used is delay-based or something else. For example, let's say a digital multi-effect unit is used in a Mesa parallel loop which has options for distortion/overdrive effects, short-delay effects (i.e., flanger, phaser, chorus), longer-delay effects (echo, delay), and reverb. Each of those effects, or any combination of them, is equally likely to produce phase noise since it is not the type of effect used but the output lag of the digital unit as a whole which is long enough to cause phase noise.
IOW, let's say you set the unit to produce a distortion effect rather than a time-based effect. A signal is sent through the amp's Send output into the unit, where the analog signal is converted to digital. Let's say you set the internal mix of the unit to 50% wet/50% dry. The wet signal then travels an (compared to analog) enormous circuit pathway through which the distortion effect is produced. The dry signal travels a somewhat shorter pathway, but is gated and buffered by the unit's internal circuitry. After processing, the unit's internal buffers synchronize both the wet and dry portions of the signal. The now-synchronized and combined 50% wet/50% dry signal is re-converted to a single analog signal.
However, because this entire process has taken a relatively much longer time to occur than it would through an analog counterpart, the final now-analog single signal (that contains both the wet and dry portions combined) enters the amp's Return input with typically a 20-50 (sometimes far more, depending on the unit) millisecond lag compared with the unaffected signal (that is, the signal that travelled only through the amp's circuitry. This lag is enough to produce noticeable white noise, and if the lag is long enough, a sine wave whine.
It is important to note that, regardless of how the mix is set on the digital unit itself, there is still only a single signal that leaves the unit. Once that signal enters the amp's Return input, there are still only a total of two signals: one which has travelled only through the amp and is therefore unaffected, and one which has travelled through the loop and the digital unit which, regardless of how the mix is set, is always an affected signal since it has been converted to digital and back again and been delayed by the unit's internal buffers. There is no such thing as an unaffected signal from the effects loop when a digital effect is used.
As to Peter, I have no desire to bother him (or anyone else not posting to this thread). If you wish to include him, you will have to do so yourself. However, were he involved here, I would state nothing different to him than I have to you. If Peter (or anyone else) were of a mind to claim that phase discrepancy does not occur between the output of a digital effect and a Mesa amp's internal circuitry, and instead occurs between the wet and dry portions of signal internal to the digital unit itself, the onus would be on him to provide evidence for that claim. Given that the opposite is easily demonstrable, and also fits everything we'd expect from electronics and what we know about the internal processing circuitry of digital effects, a person making such a claim would have quite the task ahead of him.
Despite the appeal to authority in the case of Peter Diezel, there is still not sufficient reason for anyone to be convinced by your argument, especially in the face of what is nearly overwhelming experience by anyone who has ever tried to use digital effects in the parallel loop of a Mesa amplifier. It is not even entirely clear at this point if you and Peter would be entirely in accord if Peter were here to state his views in person, especially if he were aware that we are not discussing typical parallel loops, but Mesa's specific variant which never allows for complete avoidance of phase discrepancy.
