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I posted this in the old forum months ago, since many peole found it useful I thought I could re-post it here: ___ I really think these are important things not stated (or in some cases not clearly stated) in the manual, that you need to know to start seriously programming your POD HD I ran some serious tests on my Pod HD 500 and here is what I found out (I made my tests on a POD HD500 but this is valid for HD500X and HD Pro and is very similar for the "bean" version too), I'll try to be as synthetic (but complete and clear) as possible, but this is going to be a long reading so sit down and take your time or just go surfing somewhere else Â§Â§Â§ In short: the "famous" [input-1: guitar / input-2: variax] setting gives you different levels of signal depending on the position of the first *mono* effect block you use (amplifiers included), in particular you LOSE 6dB in the "pre" path in comparison to the path A/B or post path (note that this is not the same as saying that you gain 6dB with input-2 to "same", read on). [ if you don't know what I'm talking about just go and read this thread: http://line6.com/support/thread/74045?start=0&tstart=0 then come back here to hear a different opinion on the matter] first of all, try it out: - connect a guitar to the guitar input and the Left output to a full-range linear amp (or use your headphones) - recall a "new tone" default blank patch - set input-1 to Guitar and input-2 to Variax - set mixer channel A fader to unity (0.0dB) and pan to center - set mixer channel B fader to mute - setup a noise gate* with the threshold set to 0% in "pre" position (with this setting this IS a unity gain mono fx block) - play thru it - now if you bypass it, you'll hear that it looses 6dB of level when it's active (I initially thought this was noise gate's fault, but it's NOT) - now re-activate the noise gate and move it in A or "post" path - now if you try to bypass it you'll hear that it does NOT loose any dB - try moving the block back and forth between pre and A or post paths and you'll hear more level in path A or post than in pre this was already found out at least by hurghanico here: http://line6.com/support/message/403287#403287 but it's so important that needs a dedicated and more detailed thread. [* you can repeat the experiment with other mono effects instead of a noise gate but keep in mind that, if you want to clearly hear a level difference, you need a mono unity gain (www.music-dictionary.org/unity_gain) effect, for example: - a tube comp with thresh 100% & level 2% settings will work just as the noise gate above - an fx loop block with a mono cable connected between send and return will work just the same (but also read point 2 below) - do it with an amp with medium-low gain and, moving it between pre and A or post paths, you'll hear a significant difference in gain/ovedrive/distortion, not only level difference] Â§Â§Â§ OK now that you heard it, let's see it in detail; these are the REAL schemes of the pod and fx blocks routing, yes it's done by hand and I love it ;-) As you can see the pre path is a "dual-path" while A, B and post are all stereo paths; at the splitting point, where the path A and B are born, the signal coming from input-1 is splittted to the Left and Right channels of the path A and the signal coming from input-2 is splittted to the Left and Right channels of the path B; furthermore all fx blocks have TWO inputs and two outputs and the mono blocks do attenuate by 6dB and sum their inputs, then process the result and then split their mono output to both outputs of the block; for those who don't know, notice that: - "splitting" means duplicating one mono signal to two "routes" - and summing those two identical signals means doubling the level of the original signal (which equals to 6dB more) [and some side-notes: - the "stereo dry & mono wet" effects are for example the pitch effects and the "dry" type delays, I'm not considering this type of effects in this post, but they work as expected from the scheme you see above; - you can find a list of all the fx blocks divided by type here: http://line6.com/support/page/kb/_/pod/pod-hd/stereomono-fx-list-for-pod-hd-r567 where "stereo dry & mono wet" blocks are called "Stereo Thru/Mono Effect" which I personally find less clear - the mixer control named as "pan" is actually a "balance" control because if you move it to one side (e.g.: left) it acts on the stereo or dual mono signal by doing NOTHING on that side (left) and ATTENUATING the opposite side (right)] Â§Â§Â§ So, summarizing, if you only activate input-1, in the pre path, the first mono effect is attenuating the input 1 and 2 and summing them, but, since input-2 is actually silence, you loose 6dB; in A, B and post paths the effects are receiving a doubled signal on L/R, so the mono blocks, attenuating and summing the two signals, receive the right signal level to process so using "same" or "guitar" for input-2 does not mean to gain anything, but having a constant doubled signal wich is compensated by a 6dB attenuation in each mono summing it encounters in his flow please note that I am NOT saying that using only input-1 is wrong, you just need to know that this can give you different gain results depending on the position of the first mono effect with only input-1 active (Guitar/Variax) and the same parameter values, this: is giving you more distortion than that: now, if you use those two setups with "Input-1: Guitar / Input-2: Same", you get EXACTLY the same sound with both and this is something that can not be ignored ...don't know how to be more clear than that
the HD500 Looper could attenuate the recorded signal by 6dB ... ...depending on your routing and settings. (all of this should be valid also for the POD HD Pro and bean, but NOT for the POD HD500X since its looper routing is different) The point can be summarized saying that the Looper is a "mono wet / stereo dry" fx block; you only need to be aware of this if you use the looper in "pre" position and you are one of those who think it's better to disable input-2 (for example by assigning it to variax) also, please, understand that what I'm trying to explain here is complicated so start reading only if interested, thanks to understand what I'm talking about, you need to read this post of mine and follow the signal on my graphs here: ...so, getting to the point: "the looper is a mono wet / stereo dry fx block" means that if for example you have a situation like this: - guitar connected to guitar input - Input-1: Guitar / Input-2: Variax - Looper in "pre" position - no fx - Amp Block in Path-A (path-A at unity and pan centered, Path-B muted) and you record a riff in the looper, the looped level will be 6dB less than the original signal! explanation: as a "mono wet / stereo dry fx block" the looper attenuates his inputs and sums them, then it records the result and, when playng back, sends the recorded signal to both his outputs so if you have disabled input-2, your recorded loop will have 6dB less than the original signal and will be splitted to outputs 1 & 2 of the looper, WHILE your dry signal will be present only at the output-1 of the looper now, if the first mono effect you have is in path-A, the mixed dry and -6dB looped signals from output-1 of the looper will be splitted to Left and Right channels of path-A and that mono effect will receive them at both its inputs otherwise, if the first mono effect you have is in the pre path you will hear no difference between dry and looped signals: indeed the looped signal will re-gain its lost 6dB because it will be present at both inputs of the effect (while the dry is present only on one input). so, to summarize: if you have Input-1: Guitar / Input-2: Variax and the Looper in "pre" position: 1- if the first mono effect is in path-A, it receives the dry signal at unity and the looped one at minus 6dB 2- if the first mono effect is in pre-path, it receives the dry and the looped signals both at minus 6dB consequences: This meas that, if your purpose was to have the ability to tweak your amp settings while listening to the results on the looped riff, and your amp is in path-A, you're going to get the wrong gain setting! (because you will be pushed to turn up your amp drive pot more than needed) Now, in the same situation (even while your riff is still looping), if you move your amp in "pre" position the loop will play at the same level but the dry guitar will play less distorted! solution? set both inputs to guitar (before recording the loop), and none of this problems will occur