LRN.FM - The Liberty Radio Network > LRN.FM - The Liberty Radio Network

Optimizing the audio

(1/5) > >>

KDus:
With proper feedback, Ian will be able to adjust the levels so the average content is as loud and consistant as possible, with optimum use of the bit depth and codec.
I see a variation of 6 to 10 dB between shows. I also see drops up to 10dB during quiet parts of some shows. I'm using an RMS meter and I never see audio above about -8dB and typical levels around -15dB during the live news. The average during the show is around -10dB. The plug in I'm using claims to emulate analog meters but I can't be sure the 0dB is a +4 reference or 0dBFS.

Does anyone have a way to see what the peaks look like? I haven't found a plug in for WMP or Winamp, that will accurately show peak levels.

FTL_Ian:
I have sent emails to some providers asking them to be wary of their levels, but that hasn't done much.  Ideally I could use some sort of command-line normalizing program (or would hard limiting be better?) that I could automate and pass all the .mp3s through prior to airing them.  I looked into this briefly but gave up and just asked the program providers to keep an eye on their levels - obviously that hasn't worked too well.

I have an open channel on the Compellor so I could run it through the compellor twice...

FTL_Ian:
I'm actually passing Molyneux, Gard, and Lew Rockwell through a LAME encoder to convert them to CBR as my automation software chokes on VBR, but the encoder doesn't seem to have any audio leveling features.   :(

BonerJoe:
Try this:

http://besweet.notrace.dk/

KDus:
Yes, normalizing the files would help, but real time processing can be tuned to do more. Hard limiting is the last step to tackle and, as you've heard, can get us into trouble because it undoes the tricks that MP3 type coding uses to throw away data.
Typical normalizing adjusts the overall level of a file so that the loudest peak determines the adjustment for the entire file. So, one click or pop could cause gain reduction and be counter productive. Some programs let you ignore click and pop, but then you're passing peaks that need to get limited later. It gets complicated fast, and there's no simple answer.
Step one is getting an automatic gain device to act like someone turning the volume up and down, to keep the average level the same.
The compellor is the tool for that job. Running two layers of compellor would only be useful if each channel is setup differently, The more I think about it, the more I think it is a good idea. I'll look at the book and see if one channel can be used for slow AGC, and the other for compression.

Navigation

[0] Message Index

[#] Next page