MartinDorr

Once you consider that digital models doing the tone shaping it makes no sense to think of them as gain staged elements increasing output to a louder and louder level. All those models have an ideal signal level range to run in. Signals in the digital domain do not need to to be made louder as a whole, they are transformed in their frequency content and per-frequency volume by the models. Independent from an aggregate signal level all models have limits in respect to what they do when the output of their normal function exceeds what can represented by a number (e.g., when your Amp setting would duplicate the volume and you have a spike of input level at 60% the model simply cannot put out more than 100%, i.e., it must use some internal mechanisms to limit such a signal to less than 100%. From what I measured there seem to be a -12dB magic limit in most of the Line 6 models (I have evidence for some EQs and all Amps). Once you go higher they start to soft clip (compress) and if you push them towards 0dBFS they distort more and more till they get into hard clipping mode(their internal processing can no longer limit the output to something less than 0dBFS and they simply cut off at 0dBFS. As far as I can tell the only exception is the mixer and possibly the volume pedal. They seem to do no soft clipping and simply cut when the output exceeds 0dBFS. With that in mind one would probably want to take your guitar input signal as soon as possible to a healthy high level but not exceeding the -12dB at peaks unless you actually want some amount of clipping. All subsequent model stages should be focused on shaping the tone, but not to change the level of the signal unless changing the signal level is essential to achieving some intended effect (e.g., get some soft compression w/o an effect model as a side effect of going above -12dB output). Good luck. Your millage may vary ;-), Martin PS: I gathered my data using USB and DAW for measurements.

Looks like you have a broken Sonic port. Heard of 1 other case like this. Suggest returning to seller or contacting Line 6 support for a replacement. They may be interrested what slips through their quality control. If you are not in a hurry I'd wait for a few more days and see whether somebody else has more constructive feedback. Martin

Look at it this way ... you can double your DSP power with $300.- pretty soon (and you get twice the foot switches ;-)

My guess: They or a user found a serious problem with their Audiobus support and they have no immediate plans to work on an update, i.e., document the problem away is teh next best approach from a customer support point of view (if it does not exist it can't be broken) ;-(.

Channel volume on the HD affects sound (adds soft compression or even hard cipping distortion) if the Amp model's input or output exceeds -12dBFS. The same is probably also true for effects (my guess as I have not tested most, but the few I checked show that effect). My approach on how to dial in optimal Channel Volume ... A good and simple rule of thumb is to decrease Channel Volume as you increase Drive (reducing Channel volume by half drops preamp output level by about 12dB, have no data for poweramp mode but I'd guess its the same). If Drive is really low (0-15%) and you are using a clean Amp you probably can't get a full level output even when Channel Volume is 100% and you need another Gain stage (in a post Amp effect) to make up for the low Drive setting and limited Channel Volume correction. If you start from scratch you should get an output volume base line with no Amp selected and 0db gain mixer settings. If your guitar has a really low or hot signal you may want to raise or lower the guitar input signal level in your first effect before the amp and use that as baseline. If you can measure this (e.g.via USB and a DAW), keep the signal level below -12dBFS if you want to avoid soft compression or even hard clipping if you approach 0dBFS output level. Use ouput volume level baseline as a guide, add an Amp with some target Drive (dirt) setting and dial in a Channel Volume to match the original baseline volume to get an optimally high and noise free Amp output signal. Add post Amp effects w/o changing your baseline volume. Use a Volume pedal at end of your effects chain to dial in venue volume requirements and keep the DT's Master in the 1-2 o'clock as suggested earlier.

I'd be interrested in that feature as well. Where did you find a reference that Line 6 is planning to update Mobil POD to support Audiobus?<br />Martin

Looks like the Mobile POD does not support Audiobus and thus its effects/amps cannot be used in Garageband. As far as I can tell from the audit mode (have no Sonic Port yet) Mobile POD can play iTunes library songs while doing its amp/effects modelling and mixing the result as output. Have not really used the Mobile POD and Sonic Port with a real guitar yet (just started research before buying). From teh documentation it looks like the latest Mobil POD apps update combined with Sonic Port solves many of the complains listed by many on the Forum. Only thing really missing is Audiobus support in Mobile POD and Line 6's product would compete favorably with its competitors (Sonic Port offers more features than iRig HD for same price, Mobil POD does not cost anything if used with Sonic Port and Sonic Port as well as Mobil POD (if updated to support Audiobus) would become immediately useful for many other iOS apps. Tempted to buy already - a sure bet if Audiobus support would be added to Mobil POD. Martin

You may want to check what you are automatically getting after you changed the automatically determined correct value. I never figured out what makes it go back to auto mode, but I never tried very hard ;-). It's just worth checking what you really use once you're playing around in those settings ... but it may not apply if you are always using the same output mode.

A treat for aspiring players ... there is hope that time and effort gets you to a good place. Thanks for sharing, Martin

Just like Zap said. But you may be able to rig something up with a small mixer using the DT's effect send/return loop w/o having to change patches to support a Mic/Aux path through the HD. You can even use the DT effect loop send as a headphone out (muting the DT speakers). Use the latter with care and low volume levels till you know what your headphones can take. Good luck, Martin

There are some limited uses of dual channel tones that work with a single DT amp. The 2 amps use the same topoloy (e.g., if you want to model a bridged bright and normal channel of the same amp) No preamp on 1 channel for accoustic guitar tones