Input level on effects processors

[mreaser]

I have a Yamaha SPX900 and was wondering how hot I should have my input level. Thanks for yer help.

MR

[Snarl 12/8]

OK. It's official. I have no life.

http://www.yamaha.com/yamahavgn/Documen ... SPX900.pdf

Go to page 6 of the pdf (page 2 of the manual) and read section 2. Now, what are you feeding the spx900 with? If it's got a +4 or -10 aux output (assuming you're setting this up on the aux of a mixer) will determine the setting on the back, then, theoretically, I'd set the trim for approximately "unity gain." Read up on "gain staging" if you don't know what unity is. But essentially it's the place on the knob (or fader) where it's neither cutting nor boosting the signal. Some knobs and faders do no boosting, so you set those wide open (usually) for cleanest signal.

I have no SPX, but I have a yammy rev 7, that I bought new in 1986. As a practical matter, I set it as loud as I can on the input trim without it getting overly "hissy". There tends to be a spot on the knob where the hiss just takes off and gets really bad really quickly, I back it off just a tad from from there. Then, I bring up the master aux out (to unity-ish - seriously, most knobs don't give you much of an indication of where unity is. Feel for a detent on the knob, or look for the number 0 somewhere on it's indicator graphics) on the mixer and start bringing up channel aux outs until I've got a healthy level going into the rev 7. Then, I do a little experimenting to see whether adding gain on the mixer (either per channel, or master) and reducing it on the rev 7 sounds better or vice versa and I go with whichever is least hissy. I find that the rev 7 gets hissy before it distorts or sounds muffled, so the hiss, for me is what I gauge my gain staging by with that device.

I don't know if most people do this, but I guess I usually work backwards when I'm being careful about gain staging. Like for overall monitor gain, I'll set the amp wide open, then bring up the master out to unity, then start bringing up faders until they sound great and are in good balance. At this point, I usually need to bring the amp or the master down, unless I'm doing live sound and going for maximum hearing damage.

HTH. If one of the pros responds, go with their advice. I've been a hack recordist since 1986, or thereabouts.

[apropos of nothing]

OK. It's official. I have no life.

http://www.yamaha.com/yamahavgn/Documen ... SPX900.pdf

Go to page 6 of the pdf (page 2 of the manual) and read section 2. Now, what are you feeding the spx900 with? If it's got a +4 or -10 aux output (assuming you're setting this up on the aux of a mixer) will determine the setting on the back, then, theoretically, I'd set the trim for approximately "unity gain." Read up on "gain staging" if you don't know what unity is. But essentially it's the place on the knob (or fader) where it's neither cutting nor boosting the signal. Some knobs and faders do no boosting, so you set those wide open (usually) for cleanest signal.

I have no SPX, but I have a yammy rev 7, that I bought new in 1986. As a practical matter, I set it as loud as I can on the input trim without it getting overly "hissy". There tends to be a spot on the knob where the hiss just takes off and gets really bad really quickly, I back it off just a tad from from there. Then, I bring up the master aux out (to unity-ish - seriously, most knobs don't give you much of an indication of where unity is. Feel for a detent on the knob, or look for the number 0 somewhere on it's indicator graphics) on the mixer and start bringing up channel aux outs until I've got a healthy level going into the rev 7. Then, I do a little experimenting to see whether adding gain on the mixer (either per channel, or master) and reducing it on the rev 7 sounds better or vice versa and I go with whichever is least hissy. I find that the rev 7 gets hissy before it distorts or sounds muffled, so the hiss, for me is what I gauge my gain staging by with that device.

I don't know if most people do this, but I guess I usually work backwards when I'm being careful about gain staging. Like for overall monitor gain, I'll set the amp wide open, then bring up the master out to unity, then start bringing up faders until they sound great and are in good balance. At this point, I usually need to bring the amp or the master down, unless I'm doing live sound and going for maximum hearing damage.

HTH. If one of the pros responds, go with their advice. I've been a hack recordist since 1986, or thereabouts.

Wow. +1. Gain staging isn't everything -- it's the only thing.

[Gregg Juke]

A little assist to gain-staging (admittedly a little, but); are your meters calibrated?

GJ

[mreaser]

Thanks for all the replies. I do know what gain staging is already tho. I suppose I should have been more specific about what I am doing exactly. I actually just plug my guitar right into it and then the SPX goes to my amp. Maybe this will trigger some different responses.

[Snarl 12/8]

Yeah. That's wrong. You need a preamp before it. Are you sure you know what gain staging is? 'Cause a "guitar level" signal ain't line level. You need some gain in there to get it right.

How does it sound? What about what you're hearing is making you ask this question?

[Gregg Juke]

Double-post self-deleted...

GJ

[Gregg Juke]

Well, I suppose to answer your initial question (which it seems we all may have strayed a bit from) and to also succinctly sum-up Carl's very thorough post, it might sound something like: "Give it enough level until it sounds good." While that may seem simplistic, I suppose that's really the answer.

To complicate things a bit more though-- Is the SPX-900 supposed to take direct guitar/instrument signal? I think it might be looking more for a line-level input?

GJ

[Gregg Juke]

Ah, see? ^^^^ Buffalo minds think alike...

GJ

[mreaser]

I am running through a few other effect pedals before the signal gets to the SPX but nothing that's really boosting the signal much if at all. The SPX has an input level knob and a meter that goes from -30 db to 0 db, the meter is red from -30 to -10 and green from -10 to 0. Generally I just get the input level to be just into the green zone and it seems to sound fine, when i push it up to 0 i do notice it gets a bit crackley.

[Gregg Juke]

It looks like your unit can receive +4 or -10/-20 line level signals. It is not optimized for instrument level, so depending on what you have set-up in the back (there is a switch, I believe), you might be under-loading or over-loading it (?)...

http://usa.yamaha.com/products/live_sou ... rs/spx900/

Does your amp have an FX loop by any chance?

GJ

[mreaser]

I am using a Roland Jazz Chorus 120, pretty sure it does not have an effects loop. What would I need to run the guitar into it because I really like the effects on the SPX900?

[mreaser]

Scratch what I said bout the Jazz Chorus not having effects loop, I don't have it in front of me right now but the manual claims there is a stereo effects loop

[mreaser]

Ill have to try out the effects loop next time I am in front of it

[Snarl 12/8]

You could also be having an impedence mismatch if the spx is expecting line level and "line" impedence and you're feeding it the signal from a guitar pedal. That could, potentially, kill tone too, even if you're fine with the level you're eking out of it.

Guitar -> guitar pedal -> JC120 -> effects loop out (send) ->spx900 -> effects loop input (return) -> JC120 -> ears

aught to give everything the proper level and impedence (and therefore, tone) that it's expecting.

I'm not one to say never plug things into the wrong input or anything, but that would be one of the so-called "right" ways to do it. The other way would be to use an active DI of some sort, like some mic preamps that also do DI duty and send out a line signal. Then reamp it back into the amp. So you'd go:

guitar -> pedal -> mic pre/DI thingy -> spx900 -> reamp -> jc120

That could be cool, but I'd be leery of all those extraneous pieces of gear and cables and shit.

As a drummer who survived the 80's, I gotta say, please learn to use your JC120 "properly." In the wrong hands they can become lethal. With great power, comes great responsibility.

ck