“Headroom” is the availability ofthe signal to “breathe”. In HelixNet we found the need to add this feature to the mic settings. In digital audio systems, there are at least two gain stages…analog anddigital. When the analog signal gets close to the top of the volume envelope,we start to get an overdriven distortion. In the digital domain, we are fine until we reach the top of theenvelope and then the signal turns into, what can be called “cold slaw”. Analogdistortion sounds like…well, distortion. Harsh and distorted sounds, but is stilldistinguishable as the sounds (or words in our case), but still somewhat understandable.  In the digital domain, distortion sounds likeunintelligible gobbledygook.

InHelixNet, we found that whenone would talk very loudly, we’d get a lot of analog distortion and a smidgenof digital distortion, as the gain stages clashed beyond their comfort zones and near their ceilings.  In order to ameliorate (improve make better) that, we added a MICHEADROOM option in the menu.  This raisesthe whole gain to accommodate very loud voices, in high ambient noiseapplications when folks have to scream. But with this opening of the gain window, we also see (hear, really) anincrease of the noise floor.  This is whywe have NORMAL as the default option and HIGH is set only for those situationswhen one needs to speak very loudly and a higher noise floor is not an issue.  Another thing that helps is turning off the CONTOUR CURVE setting, which addsgain at 3 and 7 KHz to increase intelligibility and can trip the digital audio gain stage into distortion, so we havebetter results in that screaming environment when we disengage that feature.