Topic: Recording overloaded/distorted - what did I mess up?

[klingklang]

I'd like to preface this by saying I'm no expert, so any layperson terms to explain or help would be appreciated!

This was my gear:

CA-14 (c) > CA-9200 > R09HR

I taped a show for the first time with that preamp and there were two variables that might have resulted in my recording slightly distorting/overloading:

1) The Limiter button on the back of my HR accidentally got shifted to ON.

2) I set the 9200 fixed gain at +35 dB with the variable/adjustable/trim (don't know which is the correct term) gain maxed out.  With those settings, the levels on my HR were at -12 for loud songs and -20 for quiet songs.

Songs are at: http://minus.com/mbjl5LvXa0
The first song didn't overload.  Click the arrow to get the second song and that one did overload (the 2-3 minute bit is when it's really noticeable in the left channel).

I set the unity gain on the HR to 13 and I went Line In with the preamp.  The filter/roll-off was off on the preamp.

I suspect I overdid it with the preamp setting.  But I wasn't getting good levels with the preamp setting at +30.  This was an 'acoustic' show in the sense it was just a guitarist, but for four songs, he played along to backing tracks and played an electric guitar over it.  Even wearing earplugs, that was excessively loud (for a dude with a guitar) and it was at a venue that is a movie theatre, so it's not like it had a normal sound crew.  So it overloaded for those 4 songs and whenever the girl next to me screamed.

The recording never clipped.  Looking at the waveform, the recording turned out extremely low.  But it flattened out during the loud parts of songs and that is where the distortion occured (this is what makes me think it might have been the Limiter).

It's probably hard to figure out what I screwed up, but basically my question is, should I run the fixed gain on the preamp at a lower setting (no higher than +30?), even if the levels on my HR are low (below -20)?  Or is it okay to run the gain as high as possible in order to get a level between -20 and -12 on my HR?

I know I need more test runs, but it's kind of hard for me to get to shows where I don't really care about the band.  And I'm seeing another show in a couple of days where it's yet another dude with a guitar/bass that plays along to backing tracks.  But I know that one is going to be loud because it's at a normal venue.

[daspyknows]

My son is running line in +30 db into a Tascam DR-2D using same mics and preamp.  My guess is its running mic in rather than line in.

[klingklang]

Oops, typo on that.  I meant Line In.  I edited my post.

Thanks dk!

edit:  Thanks to a helpful PM, I learned that I messed up the unity gain setting on the HR, which is actually around 40?  So that explains why my levels were so low.

[fmaderjr]

You have a good little rig there & I think your problems should be easy to resolve. I don't think the limiter being on had anything to do with your problem. Assuming that the show was fairly loud, I think that you overloaded the CA9200 and it "brick walled" during the loudest parts of the show. That would account for flattened peaks well  below 0 dB. The limiter won't kick in well below 0 dB.

Where you went wrong, I think, was setting the HR to 13. That is way below the estimated unity gain setting of 38-40 (the setting where the HR's preamp is neither attenuating nor amplifying). Next time set the HR to 38-40. Then your meters will go over 0 dB if the CA9200 is set too high (actually well before that point, I think). If your meters stay below 0 dB with the HR at 38-40, you should not get a distorted recording. Many of us actually aim for the meters to peak around -12 dB to allow headroom for unexpected peaks. You can easily boost 12 dB or more in post without adding audible noise when recording in 24 bits.

For a loud show, I would start with the CA9200 at 15 (trim at max) and turn it down if necessary to get levels maxing at around -12 dB. It would certainly be safe to do this with the trim if levels are already below 0 dB. If not, it might be safer to reduce the fixed gain setting (reducing the trim has no effect on whether the CA9200 will brick wall). For an acoustic show, you could start with the CA9200 at 35 and again back off if necessary.

Some of us, myself included, feel it is fine to have the limiter on as a safety valve because it won't kick in if you keep your levels below 0 dB. If you do this, make sure the limiter is on & not the automatic gain control (which we all agree is a no no). There is a menu setting on the HR described on p. 102 of the manual that sets whether the limiter or AGC is turned on when the Limiter/AGC switch is in the on position. Always have the menu setting set to limiter even if you want to have the Limiter/AGC switch set to off because the limiter will cause a lot less problems than the AGC when accidentally engaged. Or you can just set the switch to off and use a bit of tape to keep it from being turned on by mistake. You can also do with with other switches you want to make sure don't move.

[Church-Audio]

You have a good little rig there & I think your problems should be easy to resolve. I don't think the limiter being on had anything to do with your problem. Assuming that the show was fairly loud, I think that you overloaded the CA9200 and it "brick walled" during the loudest parts of the show. That would account for flattened peaks well  below 0 dB. The limiter won't kick in well below 0 dB.

Where you went wrong, I think, was setting the HR to 13. That is way below the estimated unity gain setting of 38-40 (the setting where the HR's preamp is neither attenuating nor amplifying). Next time set the HR to 38-40. Then your meters will go over 0 dB if the CA9200 is set too high (actually well before that point, I think). If your meters stay below 0 dB with the HR at 38-40, you should not get a distorted recording. Many of us actually aim for the meters to peak around -12 dB to allow headroom for unexpected peaks. You can easily boost dB or more in post without adding audible noise when recording in 24 bits.

For a loud show, I would start with the CA9200 at 15 (trim at max) and turn it down if necessary to get levels maxing at around -12 dB. It would certainly be safe to do this with the trim if levels are already below 0 dB. If not, it might be safer to reduce the fixed gain setting (reducing the trim has no effect on whether the CA9200 will brick wall). For an acoustic show, you could start with the CA9200 at 35 and again back off is necessary.

Some of us, myself included, feel it is fine to have the limiter on as a safety valve because it won't kick in if you keep your levels below 0 dB. If you do this, make sure the limiter is on & not the automatic gain control (which we all agree is a no no). There is a menu setting on the HR described on p. 102 of the manual that sets whether the limiter or AGC is turned on when the Limiter/AGC switch is in the on position. Always have the menu setting set to limiter even if you want to have the Limiter/AGC switch set to off because the limiter will cause a lot less problems than the AGC when accidentally engaged. Or you can just set the switch to off and use a bit of tape to keep it from being turned on by mistake. You can also do with with other switches you want to make sure don't move.

I would agree 100% start at unity gain then increase the gain on the preamp I personally shoot for -8 to -12 db on average on the VU meter on the R09HR and get the remainder in post via normalization.

[bryonsos]

Sorry you had trouble! Sounds like you're sorted now though.

This topic would make a good sticky:

Set recorder to unity gain (4-5 for M10, 38-40 for R09HR etc.), adjust levels on preamp to generate peaks @ -12 to -8.

FWIW, with every rig I've used (MixPre, LB, 9200 as pres, R44 no pre), if the levels are peaking in the neighborhood of -35 or so during the pre show music, then I generally don't have to make any major adjustments once the music starts. For a  situation, maybe a bit lower ~-40 would be safer. YMMV

[klingklang]

fmaderjr:  thank you for the specifics on how to set the 9200 for different situations.  That helps tremendously.  Thanks as well as to why I ended up with flattened peaks well below 0, and the info on the limiter and the manual.

bryonsos: thanks for the -35/40 pre show music tip.  I've been running it a little lower/higher than that, which would explain why I always have to make extreme adjustments once a show starts.

Thanks to everyone for the extremely helpful replies!