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Gear / Technical Help => Ask The Tapers => Topic started by: divamum on March 10, 2005, 03:54:30 PM

Title: Guesstimating rec levels?
Post by: divamum on March 10, 2005, 03:54:30 PM
Hi y'all -

Am recording tonight with a slight variation on the rig I used in this space 2 nights ago - this time I have +50 gain available to me.

My problem is there is absoultely NO opportunity to check levels (superstealth, and I"ll be onstage while the gear is out in the house).. also, the seats for the person who'll be holding on to the gear are closer to the stage (significantly) than where I taped from last time.

The other night I was at about +35, but much further away (2/3 of the way back - maybe 60+ft) in a 2200 seat theater)... it recorded rather too quietly (I boosted on the computer).  This time it'll be maybe 15-20 feet back, virtually right on top of the orchestra (this is opera, btw - all acoustic)

So, given that this is just about the most undesierable set of circumstances imagineable (read:  flying completely blind and a newbie to boot!), are there any rules of thumb for figuring out how much gain to try?     I'm assuming I'd do better to under-record rather than have it distort and, as I say, there will be absolutely NO opportunity to watch levels while it's running - it must be totally out of sight. 

I'm using AT831>sp preamp>jb3.

Many thanks for any ideas!
Title: Re: Guesstimating rec levels?
Post by: cleantone on March 10, 2005, 04:17:52 PM
I'm not sure how low the levels on your other recording were but if you'll be closer and you think it will be a fair amount louder I suggest using those levels or just a tad hotter. A low level recording would be a lot better than an overdriven one. Good luck.
Title: Re: Guesstimating rec levels?
Post by: firmdragon on March 10, 2005, 08:11:55 PM
if i was you. ii would run it at half or slightly lower than that.  i actually did a soundboard recording this way.  had super low levels, not even visible half the time, but it worked out as i was able to boost it in post.  good luck.
Title: Re: Guesstimating rec levels?
Post by: divamum on March 10, 2005, 11:53:01 PM
Thanks!  I did drop it back a bit - haven't listened back yet (having sung the whole show tonight I'm not quite ready to listen to it AGAIN before bed!! ;) but I'll let you know how it worked.

Is there any kind of mathematical formula, like there is for calculating flash distances/power required with a camera? Is gain linear or logorithmic or geometric, or... ? Just curious how it all works. 
Title: Re: Guesstimating rec levels?
Post by: Tim on March 11, 2005, 12:00:45 AM
no formula...

every microphone has a different output voltage, people pay extra money to have their microphone pairs "matched" so that their output is closer to standard. besides the differences in microphone output levels you also have to deal with the sound pressure level of the source you are recording (how loud is it?), which can't be measured until the musicians are playing. sound waves also react to the environment they are in, reflective surfaces like walls or ceilings v. absorptive surfaces like human bodies or soundproofing walls. Humidity will also effect the sound waves and potentially the spl's...

I'm sure one of the pros will explain it better than me but the point is, there are a lot of variables to contend with :)

eventually you get a feel for your equipment, the rooms you tape in, and the bands you tape so setting levels will become much easier
Title: Re: Guesstimating rec levels?
Post by: sml42 on March 11, 2005, 10:24:04 AM
eventually you get a feel for your equipment, the rooms you tape in, and the bands you tape so setting levels will become much easier

...and then you'll upgrade your rig, and start all over again ;D

best regards,
stephen
Title: Re: Guesstimating rec levels?
Post by: cleantone on March 11, 2005, 11:17:51 AM
Quote
had super low levels, not even visible half the time, but it worked out as i was able to boost it in post.

Thats fine at 24bit. When your at 16 bit you ideally want to ge the levels up as much as possable. If your levels are really low at 16 bit your not actually taking advantage of the full 16bits and your resolution is lowered. At least thats what I've gathered.
Title: Re: Guesstimating rec levels?
Post by: Tim on March 11, 2005, 11:46:24 AM
Quote
had super low levels, not even visible half the time, but it worked out as i was able to boost it in post.

Thats fine at 24bit. When your at 16 bit you ideally want to ge the levels up as much as possable. If your levels are really low at 16 bit your not actually taking advantage of the full 16bits and your resolution is lowered. At least thats what I've gathered.

you are correct
Title: Re: Guesstimating rec levels?
Post by: Brian on March 11, 2005, 11:54:43 AM
am i the only one that doesn't really follow these configs rules?

at the venues i tape i have to setup like 20cm 100º or 17cm 120º.  the only time i have i'm ever really exact is XY.  most the venues i tape in have wide stacks and a conventional config doesn't really yield the best results.
Title: Re: Guesstimating rec levels?
Post by: heath on March 11, 2005, 11:57:33 AM
i use my best judgement.  I rarely ever end up using the "standard" definition of the configs. 
Title: Re: Guesstimating rec levels?
Post by: Tim on March 11, 2005, 12:08:58 PM
i use my best judgement. I rarely ever end up using the "standard" definition of the configs.

ditto for me when I had a rig

you are not alone Brian
Title: Re: Guesstimating rec levels?
Post by: divamum on March 11, 2005, 12:23:33 PM
Thanks, as always!  Yeah, I'm sure eventually I'll get a feel for this combo, it was just using it completely untried that was a challenge (I do know how totally NOT ideal this is, unfortunately, I was overtaken by events and  got stuck with it!)

In the event, it was up  too high, alas, but I got enough to be able to hear what I wanted to. 

Another Q - I used the SP mini preamp this time, and the places where it clipped the distortion sounded like actual CLICKS rather than the usual "distortion" sound I'm used to when I've used mic in. Is this normal or is there a different problem I need to address?  Just curious.

Lastly (and this perhaps should be in a different thread... sorry!) - the JB3 turned itself off after 3 hrs despite having plenty of battery.  Is there a setting I need to use to ensure it doesn't do that?  Is this to do with the "continuous" choice in the most recent firmware (speaking of which, is there somewhere to get instruction/readme file or whatever for the extra features in the most recent firmware?  I tried to get into the JB3 faq, but the link just takes me back tot he ts home page so I'm not sure how to get to it....)

As always, my grateful n00b thanks :)
Title: Re: Guesstimating rec levels?
Post by: heath on March 11, 2005, 12:24:06 PM
i use my best judgement. I rarely ever end up using the "standard" definition of the configs.

ditto for me when I had a rig

you are not alone Brian

:grouphug:
Title: Re: Guesstimating rec levels?
Post by: Brian Skalinder on March 11, 2005, 04:38:17 PM
Lastly (and this perhaps should be in a different thread... sorry!) - the JB3 turned itself off after 3 hrs despite having plenty of battery.  Is there a setting I need to use to ensure it doesn't do that?  Is this to do with the "continuous" choice in the most recent firmware (speaking of which, is there somewhere to get instruction/readme file or whatever for the extra features in the most recent firmware? I tried to get into the JB3 faq, but the link just takes me back tot he ts home page so I'm not sure how to get to it....)

Okay, a few things here...

The JB3 probably [1] stopped recording at 3 hrs as that's the max recording length for a single WAV on the JB3, and then [2] shortly thereafter shut down via auto-shutoff to conserve battery power, since the unit was simply idling.

I believe the "continuous" setting - available in firmware 1.40 - will automically start a new file when the JB3 reaches the 3 hr mark.  This should prevent the auto-shutoff from happening since the JB3 will continue to record, instead of idle.  Additionally, you may configure the auto-shutoff to never auto-shutoff, or set it to 5, 10, 15, etc. minutes.  Of course, setting the JB3 to never auto-shutoff wouldn't have helped in your case since the recording still would have stopped at the 3 hr mark because it wasn't set to "continuous" mode.

What link are you using to access the JB3 FAQ?  Lemme know, the link probably needs fixing given some recent changes around here, and I must've missed it.  At any rate, here're known-good links to the JB3 FAQs:

NJB3 Tapers FAQ (http://taperssection.com/index.php?topic=16338.0)
NJB3 Operating FAQ (http://taperssection.com/index.php?topic=16341.0)
Title: Re: Guesstimating rec levels?
Post by: divamum on March 11, 2005, 05:07:57 PM
Hi -

I've just been trying the link at the top of this forum, titled "JB3 questions? Check out the FAQ!!".  I click on it, and get linked to the redirect page, and then it goes straight back to the home page... I tried copying/pasting the link and got the same result.  HTH!
Title: Re: Guesstimating rec levels?
Post by: Brian Skalinder on March 11, 2005, 06:57:08 PM
I've just been trying the link at the top of this forum, titled "JB3 questions? Check out the FAQ!!".

I can't believe I missed that one when I cleaned up a few of the links to the FAQ.   :-[  Fixed!
Title: Re: Guesstimating rec levels?
Post by: Tim on March 11, 2005, 06:58:00 PM
I've just been trying the link at the top of this forum, titled "JB3 questions? Check out the FAQ!!".

I can't believe I missed that one when I cleaned up a few of the links to the FAQ. :-[ Fixed!

jeez brian, what are we paying you for anyway? ::)

;)