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!
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
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