Why should TZF be inappropriate to the sound of guitar?

[radio]

Hi , I bought myself this new toy,as I don't have the skill to build one:

http://www.adaamps.com/Products/ada-PBF-Flanger/PBF-Flanger.htm

In the manual they stated like I wrote in the title,that thru zero flanging is not best for guitar.

Whats their point? Normally Thru Zero flanging is considered the holy grail for this effect ?!

What am I missing??

[pinkjimiphoton]

to really do TZF, you need to delay the entire signal a little before flanging. that would probably add some latency to the guitar signal, maybe enough to be annoying.

but i don't get it either, the whole DEAL is the sound of that.

[Mark Hammer]

It's not "inappropriate", but it can often be noticeably uninspiring.

Keep in mind that the "magic" of TZF occurs from the manner in which it seems to sweep in out of the clouds and "infect" the signal.  The most dramatic and appealing examples of TZF that we're familiar with have been applied to very wide bandwidth multi-source mixes, rather than single instruments with limited bandwidth (like guitar).  TZF will sound amazing on white noise, and generally sound better on fuzzed guitar than clean guitar, but the things it does well will not be particularly apparent when playing a clean humbucker-equipped guitar through an amp whose speakers taper off above 6khz.

Think of it this way: it's like paying more for speakers that go up to 50khz instead of 20khz.

That said, the A/DA has a really nice wide sweep, that can easily begin/end above the highest point in the bandwidth of whatever signal you feed it.  It may not be TZF (which would require two BBDs, compared to the one that the unit has), but the sweep goes up high enough to provide that down-from-the-clouds drama.