Re: Line 6 POD HD Series
It still sounds flat compared to a speaker mic'd, so does the Axe FX to my ears. I suspect the Axe FX uses the extra processor muscle for effects. I've heard a lot of demos of the Axe FX and I'm not sure the price difference is justified. I think with a Vox ST, Boss GT10 or POD HD and a high quality effects processor you could get pretty close.
I brought one home today (HD500) just to try it out and one thing I noticed in the manual is something I haven't seen mentioned around the net: They mention that as not all models are equal in the amount of DSP processing power they require, the models that require very little processing power can have a longer and more varied effects chain. The opposite is also true - if you select an amp model that requires a lot of power, you will not be able to select certain effects that together would require more power than what the processor has.
Based on this alone, it appears to me that if you buy an Axe Fx you're paying for (in addition to the boutique price) the cost of putting the cadillac of the SHARC series processor in your rig. In this way it seems a lot like the tradeoff one makes when building a home PC - you can get the bleeding edge of CPU power for 3x what you will pay for the chip with the best price/performance ratio. More power = capability for longer effects chains with more complex models requiring more processing ability.
That's not to say you will always be using it - not all of the POD HD's models require even the kind of processing power it has - the extra they make a point to offer up in extra effects processing.
That's basically where my thinking takes me - Many of the models are in another dimension compared to those on my XT, when I play them both through my headphone monitors. The JCM800 preset sounds a lot better although it's not blowing my hair back or anything. XD
btw - not everyone may know this but the HD400 is more like the XT with one amp modeling at a time while the HD500 is more like the X3 with dual amp models. Just throwing that out there in case someone who hasn't already got one decides to go out and get one...
The other major thing I've noticed is that while the dynamics may seem more real through headphones, through my Atomic (112 (18w)) I really don't see the additional benefit. That is to say, the XT really shines through the Atomic and the added advantage of the HD modeling doesn't really carry all that much over, either with pre-amp only or the full model + cabs