2 noob questions. what are impulse responses-and what is the purpose of "bussing"?

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ColdToTheTouch

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2 noob questions. what are impulse responses-and what is the purpose of "bussing"?

been learning alot about using plugins and Im really enjoying how much you can do with these bad boys. I was watching a tutorial about guitar amp sims, and the guy kept mentioning loading "impulse responses" And every time he mentioned this i got completely lost. Is that like, basically... presets... for whatever plugin youre currently using,? and my next question.. which is a really dumb question

what is a "bus"? and no, im not talking about the long yellow vehicles that drive around bringing liddle kiddies to and from school. I mean on a mixer. I never understood the purpose, so ive never used them, but im hearing more and more about them and it seems to me that they are extremely important and absolutely necessary for making professional quality material. im sure there are sites all over the 'net regarding both of these topics... but id rather come here and get real answers from all you talented individuals!!! thanks alot for all your time, and I hope to hear back fro someone soon..

Shawn
 
Hi there.
The only time I've seen 'impulse response' used is in reverb plugins.
You can load the impulse response of a certain hall, room etc.
It's a profile that allows a reverb plugin to emulate a certain environment.

A bus......
In an analog console you'd have an input, a fader and an output.
Often you'd also have insert points (kinda like effects loop) and sends.

Sends could be for secondary mixes or for parallel processing; That kind of thing.

In our recording software, an auxiliary bus is where a send goes.
In Protools I could have an audio track playing straight out to my main outputs, but I could also use a send to pipe that signal to an aux bus.
The bus might have a heavy handed compressor on it.
Now I have two faders, one of which allows me to introduce parallel compression.

Sometimes we set up a reverb bus and use sends from a number of tracks to feed that bus.
That means several tracks can share the same reverb without having to run several instances of the plugin.

Hope that's useful.
 
Ipulse responses are (for a lack of a better term) "samples" that you trigger. They're not just used for reverbs. There are many guitar and bass impulse responses. So, for example, you can set up an impulse of a Marshall cab being close miced by an sm57. When you set it up as an effect on your guitar track, your guitar triggers the impulse and, supposedly, gets you the sound of the Marshall and the 57.

Steen got the rest of his post right. :)
 
RAMI said:
They're not just used for reverbs.
Click to expand...

I know that.
I actually meant to speculate that in the OPs context, impulses might be for emulating a cab or whatever, but forgot. :p
I wasn't certain anyway. I don't use them.

Good info!
 
and this is why I come here for answers. you guys really kick ass..both replies helped. just have to do more research on how I can effectively utilize busses and impulse responses. but with the impulse responses, are these something I have to download, or is it more like a set of instructions/amp settings that i need to dial in to my amp sim?
 
Depends what amp Sim you're using. Packages like PodFarm usually don't call them impulse response files, even if that is how they work behind the scenes. You generally cannot just load any old IR that you've downloaded into there and make it work. Other packages work differently, I guess.

An Impulse Response file really is exactly that - a file which describes how the program should respond in the time and frequency domain to a given input. They are usually generated by running a broadband "impulse" (a perfect step function is ideal, a balloon popping is sometimes close enough) or a sine sweep (a tone whose pitch rises or "sweeps" through the audible spectrum) through whatever you're looking to emulate. The result is recorded and then analyzed in a process called "de-convolution" which basically tells which frequencies are attenuated or reinforced, and which resonate or ring on after the initial impulse. The result of that file is your IR, which you load into a plugin which takes your input and "convolves" it with the IR file and the output theoretically sounds like if you had put the input through whatever you made the IR from.

They are really great for frequency and time domain type effects like the filter action of a guitar cab or the reverb of a natural space. They don't work well to reproduce amplitude dependent effects like compression, distortion, etc.
 
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