Excellent question !
I was thinking about something related to this the other day…particularly at how guitar effects would sonically change according to he types of preamps and speakers used in a system.
The main aspect remains a personal aesthetic choice. Will your guitar have to sound as a typical guitar or are there any different sonic choices being considered here? Some people love the sound of console channels direct clean guitar sound (think about many funky comping parts or clean chords ? la Landau in the '90s). Others love the typical guitar+gtr amp sonic response, with its dips and peaks and reduced range extension.
There are 3 ways to get these sounds. For the classic gtr sounds there is no question….gtr amp and gtr speakers are a must. They "make" the sound and the fx will sound organically related to the source.
An extended range gtr sound would not only imply the use of full band speakers but also of a non_typical gtr preamp, being these highly colored and somehow limited in response (not as much as gtr speakers though). In this scenario one would use full band equipment…but should consider that classic gtr sounds may be hard to get.
The third approach is an attempt to cover both sonic worlds, classic gtr tone and full band ones. This may be obtained by using two systems and switch between them (MIDI switchers/mixers/routers) and using effects accordingly…or using a single system with "hybrid" sounds that can cover both, particularly a preamp capable of doing both, whatever is the choosen technology in it (modeling/emulation/etc.). These preamps often use a direct line sound that IS full bandwidth (my SansAmp does it well!).
The key is ear experimentation anyway!
Now FX!
You take reverb as an example. Well….not always the theory will sound better than the practice. Reverbs are typically bandwidth limited…this is a reality truth. Somebody defined that nothing happens above 4000Hz in a real world reverb environment, after careful analysis of different spaces. Personally I wouldn't really care of high frequencies like 10K or higher. They are quite disturbing in a verb. Usually one important aspect in this effect is to find the +perfect+ tonal response in the tail, darkening even with long fades.
The quality/purity of effects in your harmonizer is terrific…BUT…it will always depnd on how much of them is introduced by the source in the system (gtr/preamp) AND by your personal taste.
Personally I love the sound of my Genelecs with any Eventide (and other brands) FX units, but I'm aware that my PSA-1 is doing the trick of providing excellent classic gtr tones and more hi-bandwidth ones. But it's also true that last weekend we had a recording show in Milan and man…..did Time and Mod Factors sound GREAT thru a classic gtr Marshal combo amp!
The key here is not sound/physics theory about bandwidth and response to it. It's about personal aestethics and taste. In a perfect world a system capable of delivering both is a great tool for the adventurous. I have no recommendations though as I like both…. but distortions would be ugly to hear and their verb almost "white noise" thru a full band preamp/speakers system.
Some may also question that a full range speaker would make sound the effect not sonically coherent with the gtr source…..
There is really no answer. There's only YOUR ear,,,and a lot of painful tests!
I
