Not sure what you're expecting them to say. They have a proprietary method they use for cab modeling, and I can understand why they wouldn't just divulge everything about it. DI did write a blog post about it a while back. I don't know how to link to specific post from this page, but it's here (scroll down to the post from 2015.09.15): http://line6.com/helix/blog.html/ Along with its suite of internal speaker cabinet models, Helix also allows you to load high-quality impulse responses from third parties. While this is a fantastic option to have, it’s important to note that the factory speaker cabinets in Helix offer a number of advancements over traditional static third-party impulses. We call the speaker emulations in Helix “hybrid cabs”, because they use a number of proprietary algorithms to reproduce the same frequency and dynamic accuracy typically seen in a 2048-point impulse response, but at far lower DSP usage. Not only that, a hybrid cab allows you to move the microphone from directly on the grill to up to 12 inches away (in .5 inch increments), and accurately captures the proximity effect/bass boost of the microphone in all positions while doing so. All of this detail means that the speaker cabinet reacts just like the real thing, not just sounding better but feeling better under your fingers. Due to the efficiency improvements hybrid cabs offer, it’s actually possible to run up to four speaker cabinets at once in Helix (depending on DSP load), all with different microphones and microphone positions!