Support and General Use > Recording
recording from the soundboard
petur:
for some odd reason the irivers can record without clipping at -xxdB, but not too much. I think -9dB is too much or on the limit. The best test is to check your recording. If there's no clipping, you're fine ;)
peteswensson:
I agree with Petur, the best strategy is to check your recording. Finding the best initial setting is trial-and-error, and after a while you will have a sense for suitable starting levels.
Clipping is a signal that is too strong for the electronics to handle without distortion, and it appears in the waveform (that you view on Audacity) like a signal with a flat-top hairdo. You might want to experiment by running a line-level signal into your iriver from your stereo (e.g., from tape out) and push the iriver record levels up until it overloads and distorts. You'll get a clear idea of what clipping sounds like, and then when you are monitoring the recording at the concert, you'll know what to look out for.
There are actually several possible sources of clipping in the recording chain. The recording chain has several discrete stages at which some amplification may take place, one after the other, each of which could be overloaded. Sometimes a singer will get right up on the microphone and holler into it, and overload the microphone circuit, which might have a limit of 100 dB, for example. Or, the pre-amp (trim pot) on the mixing board could be set too high, overloading that circuit. Then there are one or more other amp circuits that follow in the mixing board. As an amateur, I have learned from wretched experience how to screw up the gain sequence in a mixing board and cause that clipping. Pros are unlikely to do that to you, but if this is a beginner sound man, it can happen.
When the signal is passed to the iriver, its input circuits can be overloaded on the entry (i.e., a signal that is "too hot"), and even though you lower the internal amp gain of the iriver through Rockbox, you still get a distorted signal recorded, despite not having the clipping signals going off on the iriver display. The solution is to lower the signal output from the sound board; the sound man will know which knob controls the level of the feed to you.
I especially like the AGC-Safety setting because it gently lowers the gain in 1/2 dB increments so that it is not too obvious in the final recording.
Pre-record is handy for keeping the band from giving you a rude surprise by starting up when you didn't expect it. But take note: you can only set it to a maximum of 30 seconds (not several minutes). It records continuously, maintaining a 30-second buffer of audio data, dropping off the oldest data to make room for the newest. So if you are out in the audience and the band starts up, you have 30 seconds to dash back to the recorder to push the record button and catch the whole act. Pretty cool.
My H360 and H380 started life as H340s. It is very simple to swap the 40 GB hard drive for a 60 or 80 GB hard drive (Toshiba MK6006GAH or MK8007GAH respectively). These are 8mm thick, and will not fit in an iriver H320. For that, you need a 5mm thick Toshiba MK3006GAL (30 GB) or MK4007GAL (40 GB). The 30 GB drive can be found on the net for $30 to $50 or so, the 40 GB one for $130 to $150. Another option is to replace the hard drive with a 32 GB compact flash card and adaptor for around $80-$100 depending on the speed of the card you choose. It is more complicated to install the card, but the results are very pleasing. My H332 and H308 started life as H320s. (Actually, I have now changed my H308 to another H332, using a different brand of CF card.) There is more info on either the hard drive upgrade or the CF upgrade elsewhere on the Rockbox site.
I think a 200ms AGC delay time should work fine.
When the AGC setting is Safety, the gain can vary a fair amount from start of recording to finish, but don't worry. Use Audacity to level out the volume levels in the recording for the final product.
xmixahlx:
thanks for the replies (again) guys,
the recording reached -9.5dB, but i didn't amplify the signal more than 7dB. it DID clip on a few occasions (3 times in ~10 hours of sets), but only because i had been using the AGC Live setting, which moved the gain too high for the signal.
to fix the recordings, i used audacity and a combination of amplify, leveller (light, -70dB floor) and repair for some short (non-clipped) sounds in the mix (as well as fade in/out). hopefully i won't have to do that again! although i am now pretty confident using audacity :) - are there any other tools or methods that i should check out?
i wasn't able to record again (they already had someone recording the soundboard) to use the AGC Safety settings that y'all recommended, but i sure will do that next time.
if you want to check out how my recordings turned out, here are some mp3 preview encodings (lame V6 ~128kbps):
(btw, this is hardcore music, burning fight book release shows in chicago...)
--- Code: ---http://rapidshare.com/files/232598393/Burning_Fight_Chicago_20090502-Phase1-106-Ringworm.mp3.rar
http://rapidshare.com/files/232607685/Burning_Fight_Chicago_20090502-Phase1-107-Guilt.mp3.rar
http://rapidshare.com/files/232618778/Burning_Fight_Chicago_20090502-Phase1-108-Underdog.mp3.rar
http://rapidshare.com/files/232627219/Burning_Fight_Chicago_20090502-Phase1-110-Killing_Time.mp3.rar
http://rapidshare.com/files/232639765/Burning_Fight_Chicago_20090502-Phase1-111-Trial.mp3.rar
http://rapidshare.com/files/232645443/Burning_Fight_Chicago_20090503-Phase1-201-Harms_Way.mp3.rar
http://rapidshare.com/files/232651940/Burning_Fight_Chicago_20090503-Phase1-202-The_Killer.mp3.rar
http://rapidshare.com/files/232658543/Burning_Fight_Chicago_20090503-Phase1-203-Blacklisted.mp3.rar
http://rapidshare.com/files/232663679/Burning_Fight_Chicago_20090503-Phase1-204-Have_Heart.mp3.rar
http://rapidshare.com/files/232670994/Burning_Fight_Chicago_20090503-Phase1-205-Threadbare.mp3.rar
http://rapidshare.com/files/232677389/Burning_Fight_Chicago_20090503-Phase1-206-Split_Lip.mp3.rar
http://rapidshare.com/files/232683018/Burning_Fight_Chicago_20090503-Phase1-207-Reach_the_Sky.mp3.rar
http://rapidshare.com/files/232689390/Burning_Fight_Chicago_20090503-Phase1-208-Bane.mp3.rar
http://rapidshare.com/files/232698599/Burning_Fight_Chicago_20090503-Phase1-209-Converge.mp3.rar
http://rapidshare.com/files/232708923/Burning_Fight_Chicago_20090503-Phase1-210-Unbroken.mp3.rar
--- End code ---
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