- March 18, 2007 at 8:30 pm #6869mojoeParticipant
Total posts : 25
Audio processing comes up here frequently, so I thought I’d share what I am currently using. Like many others, I am using ZaraRadio for automation. The output is sent to Virtual Audio Cable, then to VST Host. The output of VST Host goes to the sound card. Virtual Audio Cable costs $30. The others are free.
VST Host does what its name implies. You can load multiple VST plugins and connect them together. Here is an image of VST Host with some plugins. I have reset the various plugins to default settings in the picture, to avoid confusion.
You may or may not need the EQ. I use it because my material is OTR, which needs a boost in the mid-range to increase intelligibility. The JB Broadcast Processor plugin has several presets you can try. The meter and Inspector plugins are not needed, but it is nice to see what your signal looks like. All of these plugins are free and can be found via a Google search. There are many other free VST plugins out there, as well.
I tried several different plugins, but so far, the JB Broadcast Processor works the best for me. I heard about it on the ZaraRadio forum recently.
If anyone who really knows about compressors, limiters, etc. would like to suggest settings to use with AM, I would be anxious to hear from them. I modified the FM preset to something that sounded ok to me, but I would welcome some input.March 20, 2007 at 10:48 pm #15083mojoeGuest
Total posts : 45366
As I said in the last paragraph of the above posting, I would welcome some input on settings to use for audio processing. Certainly, there are folks on this forum who know a lot more about this topic than I do.March 21, 2007 at 1:28 am #15085WILCOM LABSGuest
Total posts : 45366
I am no expert,but have had some experience with AM.First,I would cut off everything above 10kcs and add some mid boost around 2kcs. Adding a lot of low end will tend to muddy up the sound,so leave it fairly flat. Then add some compression to your liking. You have to tweak it to match your particular equipment. I also listen on several different receivers to give a more critical listen. It helps if you can watch the modulation envelope on an oscilloscope and get as close
to 100% with as little distortion as possible.
Regards,LeeMarch 21, 2007 at 4:42 am #15089RattanGuest
Total posts : 45366
The problem, mojoe, is that there are so many factors involved. What transmitter, what cables, what sort of antenna.. and then things like what sort of board or console you use and how you like it set up, etc. All those things have an effect as does your source material.
There is no one absolutely best way to go about it and about the only “universal rule” I could tell you is the final piece of test gear is ears. If it sounds good on a reciever and you aren’t overmodulating the signal enough to cause it to generate sprogs/spikes out of the allowed RF band, then you pretty much did it right enough.
Fine tuning it to get the sound just the way you and your listeners want it is an art and personal taste is the largest part of it.
Looks like you have a pretty reasonable setup for experimenting with. I couldn’t run it on the machine I run zara on, too ram intensive. So I tend more to outboard solutions. Every station is going to go about things a bit differently based on what they have and what the owner/operator is familiar with using or willing to learn.
Another thing is you can really beef up the audio signal and/or put in things “the pros use” like pre-emphasis and certain compression setting.. and have your listeners not like it as well. I ran into that when I tried running Sound Solutions to take care of the 15 khz clip and pre-emphasis and a theoretically much more pro sound. I liked how it sounded (though some of that was “kid with new toy syndrome”) but when I asked my listeners, they were less fond of it. They said it felt “too loud”, “too in-your-face”, “too harsh”, “dirty”.
First thing I figured out in trying to adjust it was that not one of them liked the pre-emphasis. Every website and forum I’d seen said it should be there, but ok, took that off. And I went on turning parts of it down or off until finally I just hooked up the line I’d been using which was just a “brickwall” limiter right before the transmitter, an equalizer right before that to compensate a bit for the transmitter and reciever audio frequency tendencies and kill off everything around 16khz and up, and just a little compression before the eq. Other than that, zara’s AGC. And that was what they ended up liking.
Then I wanted to do a bit of recording, and needed the compressor in the studio. So I cobbled in a couple parts on the limiter to soften it just a little (though that kind of makes it no longer an actual “brick wall”) and they noticed the change and liked the sound better. So I never put the compressor back in that part of the line. Instead I put it on the Behringer board I use for a submixer for mics and outboard sources (the final mixer being the computer when I’m using zara). It evens out the mic and older analog sources a bit, so it earns it’s keep there.
But the point is that the way it sounds coming out of the receiver and if it appeals to the listeners’ ears (even if you’re the only listener you’re sure is hearing it) is the bottom line.
Aside from that, the presets on a lot of sound software are at least good places to start, and tweaking them until they sound good is one of the quicker ways when you’re using mostly software audio treatments. I find the compression on most default settings a little higher than I like, so I usually try taking them down a notch or two.
DanielMarch 21, 2007 at 11:05 am #15090mojoeGuest
Total posts : 45366
I started with the “FM” preset on the JB Processor plugin. Then I turned down the compression to 2:1 and disabled the “widening” feature. This sounds ok to me and added just a bit more punch at the 1mi range.
As for running this stuff on the same PC with ZaraRadio, yes, audio processing does take a lot of CPU cycles. However, I am running everything on a P4, 2.66GHz PC. Last year, when I upgraded my main PC, I built the automation PC out of spare parts (and a few new ones).
I find that with ZaraRadio and the audio processing software, the CPU is running about 45%. For comparison, I originally tried Sound Solution, but it ran close to 100% all the time. I have a stripped down WinXP on this PC and no unnecessary software (not even a web browser).
One thing that I did do that made a tremendous difference was to set the priority of both ZaraRadio and VSTHost to “Above Normal”. It is actually VSTHost that needs this more than ZaraRadio, when running both on the same PC. With normal priority, any other activity on the PC will cause the audio to stutter. With “Above Normal”, I can run a second copy of ZaraRadio to edit a playlist, transfer files across the network, run a nightly backup to a second drive, etc. without any audio stutter.
To start these programs on bootup and set the priority, I use a batch file. I found a freeware program called “Process” that sets a program’s priority from the command line. You can find it here: http://www.beyondlogic.org/consulting/processutil/processutil.htm
Make sure that you don’t use “High” or “Realtime” priorities, or you will have a hard time using the computer. With “Above Normal”, you will notice a slight delay when running other programs, but it isn’t objectionable.
I should mention that if anyone wants to try using a similar combination of software, you will also need another free program called ASIO4All. Without this, VSTHost won’t allow using Virtual Audio Cable for input.
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