Felix,
(edited to note that jmaziarz and cudamark responded to you while I was typing up the following, ridiculously long message, LOL, and I agree with what they said, as well).
No, you don't have to worry about "too many programs" acting to "slow down" your machine. The processor in the machine is MORE THAN fast enough to do whatever you ask it to do, settings-wise, without "bogging down."
Perhaps a better way to think of it, is that it is good to understand what each one of the settings accomplishes individually, and then learn to "tune" each setting to the site you are hunting, the conditions there (ground, EMI, etc.), the type of targets you are hunting for, whether you are trying to locate deep targets, targets in trash (or both), etc.
Take sensitivity, for instance. The general rule of thumb with the EQX is to run sensitivity as high as you can, SITE-DEPENDENT. In other words, run it as high as you can, without whatever EMI is present becoming "obtrusive." Obviously, the higher the sensitivity, the weaker of a signal return that will be reported to you, as an audible tone. So, high sensitivity is GOOD, in that it can allow you to hear a weak signal emanating from a deep target. HOWEVER, if there is EMI present at your site, then running high sensitivity will ALSO allow weak signals emanating from EMI to be reported to you, as an audible tone -- and thus the machine can sound "chattery" as a result, and eventually possibly overwhelming you, in terms of "mental fatigue." So, in those situations, there's no REASON to run sensitivity high. YES, by lowering sensitivity, your machine may not report to you the weak signals emanating from the deepest targets. BUT, it's a moot point -- because obviously, if you are setting your sensitivity high so as to hopefully hear that weak, deep signal, but as a result, you are also being barraged by weak EMI signals, then that weak signal from the deep target would be "buried in" and "indistinguishable from" all the EMI chatter anyway.
So, my long-winded point there is, instead of thinking of some "combination of settings" that someone somewhere may have chosen to use at some point, it's better to understand each of your settings INDEPENDENTLY, and know what each one does. Then, YOU can decide how to set up your machine for YOUR situation, AND you will better understand when, and why, you might want to adjust those settings.
We've discussed sensitivity, and what it does. Along these same lines, to add a bit more to the discussion about Iron Bias, and about Recovery Speed, and how to utilize them...
Iron Bias is basically a setting that alters the way a "combination" target -- i.e. a target that is a mix of iron ID and non-ferrous ID -- responds. The LOWER you set your iron bias, the less you are "biasing" the machine toward giving an iron signal. In other words, you are allowing the non-ferrous tones (higher tones) to be reported to you, ALONG WITH the iron tones. Obviously, that's GOOD if you are trying to find "combination" targets -- i.e. coins mixed in with iron, for instance. With these types of targets, running low, or no, iron bias allows your machine to report BOTH the high tones, AND the iron tones. This can then "clue you in" to the possibility of a non-ferrous target existing near the iron target, and might therefore alert you to dig. Meanwhile, running the iron bias at progressively higher settings, means you are telling the machine to allow the iron tones to prevail -- i.e. to "minimize" the high tones, and instead "accentuate" the iron tones. As a result, you'll be less tempted to dig a "falsy" nail, for instance, but with the downside being that you'll ALSO be less likely to dig a nail/coin combination target. So, if you want to minimize the iron you dig (i.e. you want iron targets to SOUND like iron targets to the greatest degree possible), run iron bias HIGH. On the other hand, if you want to "hear it all," i.e. the iron tones MIXED WITH the high tones, so as to hopefully maximize your ability to find those "nail/coin combination" targets, then run iron bias low.
Recovery speed is, despite what some think, essentially just "clipping" a tone, as far as I understand it. It doesn't actually "speed up" your machine, but it can give that "appearance" that it does so; in truth, though, it is really just altering the way tones are outputted/reported to you. To describe, a musical analogy may help. In music, there are two opposing terms that I feel are applicable -- staccato, and legato. Staccato is defined as short, abrupt notes (choppy, as I might describe it). In other words, each note is kept short, and thus there is "separation" between each note. On the other hand, legato is the opposite. Legato is where each note is "drawn out," into a "smoother" flow of the music, without much, if any, break between the individual notes. If you can imagine these two terms, with respect to music, then this I think will help you to understand recovery speed.
The lowest recovery speeds yield a "legato" nature within the audio output. As such, when hunting in trash, where there are lots of tones being reported to the user, the tones will tend to blend/run together more, at low recovery speeds. As a result, these "lengthened in duration" tones, running together with each other, can make it harder to pick out individual tones, within the "blend" of noise. HOWEVER, the benefit is, when hunting where there is NOT a lot of trash, a "lengthened" tone might catch your attention more, and so a deep target giving off a subtle, quieter tone will be "lengthened" a bit, at lower recovery speed, making it potentially a bit easier for you to hear or "notice" it, and thus more likely to dig it.
On the other hand, high recovery speeds are imparting a "staccato" nature to the tonal output of the machine. So, when hunting in dense trash, there is more "separation" between the tones; you are more likely to hear the short, brief tones as representative of their separate targets, as opposed to being a "blend" of a bunch of tones. As a result, it may thus be easier for your ears to pick out a specific tone that you may be listening for, amongst the barrage of other sounds, given the more "staccato" reporting of the tones (as opposed to running lower recovery speed where the tones are more blended together). High recovery speeds, i.e. shorter tone lengths -- and thus more separation between tones -- might SOUND like the machine is "processing faster," but actually it is simply that the AUDIO REPORTING is altered (shorter tone length, versus longer tone length -- i.e. blip blip blip versus bleeeeepbleeeeepbleeeeep).
So, again, I think that if you can think about each of these settings (sensitivity, iron bias, and recovery speed) INDIVIDUALLY, and try to think about what types of hunting scenarios you might encounter, and how in each scenario some adjustments of these settings might help or hurt, then I think you will be better off -- as opposed to trying to find some "magical combination" of the settings.
Steve
