Ok - stupid question here - Impusles?

[Jerry W.]

Hi All!
Bear in mind that I am a total newbie at software based stuff - what are impulses? Do they have to deal with reverb? What software uses them?

Thanks for your patience and time in responding.

Jerry Wickham

[dnortana]

Hi Jerry,

Impulses are vernacular for 'Impulse Responses', which are mathematically processed recordings of the reverbration characteristics of a given space. This could be a canyon, a room, a car interior, or a concert hall. They got their name from the technique - often firing a starter's pistol (an impulse) and recording the resulting sound over time (response).

This 'response recording' gets processed, so that it can be used with a 'convolver' - a software program capable of combining the IR with an audio signal so that the result is the audio signal appearing to be in the IR's space. This process is generally called Convolution Reverb, and there are some very good programs now for this -AltiVerb for Mac, Space Designer (Logic Pro), and others.

There are free convolvers available (try googling on 'SIR', a popular one), and many free (and some very excellent) IR's.

Trond

[Jerry W.]

Thanks Trond for taking the time to reply.

I had a feeling they were something like that. I will definitely investigate these! I would love to ad that kind of enhancement to my recordings.

Thanks so much for your help!!

:) Jerry Wickham

[Jeff Turner]

I'm new to this also, but my understanding is that SIR is PC only. For those of us in Macland, do we need Altiverb to use IR's?

Jeff

[dnortana]

Hi Jeff,

Sadly, SIR is indeed PC only. I don't know of any free-ware Mac convolution reverbs at this moment.

AltiVerb has been the premiere Mac convolution reverb for some time, but now there are other possibilities. Waves came out with IR-1 recently, and Logic came out with Space Designer just before that.

FWIW, here's a list of known convolution reverb processors, including a couple for Mac I had never heard of before: 'Gleetchplug Maelstrom' sure has an interesting name :-)

http://www.spiritcanyonaudio.com/convolvers.php

Trond

[NDEE]

Impulses are vernacular for 'Impulse Responses', which are mathematically processed recordings of the reverbration characteristics of a given space. This could be a canyon, a room, a car interior, or a concert hall. They got their name from the technique - often firing a starter's pistol (an impulse) and recording the resulting sound over time (response).

This 'response recording' gets processed, so that it can be used with a 'convolver' - a software program capable of combining the IR with an audio signal so that the result is the audio signal appearing to be in the IR's space. This process is generally called Convolution Reverb.

Hi,

So what is the difference between this "Convolution Reverb" and "conventional" reverb???

Is the Ambience reverb (in GPO Studio) considered a "Convolution Reverb" ???

If not, can a "Convolution Reverb" program be used instead of Ambience, or maybe combined with Ambience ????????

NDEE

[Styxx]

Hi Jerry,

Impulses are vernacular for 'Impulse Responses', which are mathematically processed recordings of the reverbration characteristics of a given space.
Trond

So, if a tree falls in the woods and there is no one there to record it is there still and 'Impulse Response"? :D Just kidding!

[dnortana]

Hi,

So what is the difference between this "Convolution Reverb" and "conventional" reverb???

Is the Ambience reverb (in GPO Studio) considered a "Convolution Reverb" ???

If not, can a "Convolution Reverb" program be used instead of Ambience, or maybe combined with Ambience ????????
NDEE

Ambience is a 'conventional' reverb. I guess you'd say that a conventional reverb is based on a mathematical simulation/calculation of a space, taking into acount the arrival/frequency content of both early and late reflections, diffusion throughout the space, absorption characteristics of walls and ceilings, etc. Keyword: a mathematical model/calculation.

The convolution technique, on the other hand, is based on the actual measurement of a real process (usually a space, although the technique can also be applied to hardware/circuits - like, say, a Lexicon 960).

A convolution reverb could be used instead of ambience, or even in conjunction with it, or vice versa - they're just two different techniques to add a sense of depth/space to music. Some pro's like to apply a small amount of reverb with an almost non-existent tail to various instruments in an orchestra, to add just a little air, and then push the final mix through a common convolution reverb to put the whole orchestra in a common space. Some people will use entirely different reverbs on different instruments - it's all just part of the art of mixing, and what result you are trying to achieve.

Some of the best original orchestral mockups on northernsounds used to be done by a guy named Thomas J - he always claimed he just used the reverb in his SoundBlaster card. So obviously, you can get great results without getting exotic - if the writing, orchestration and mixing are good.

Trond

[Shazbot]

I've been trying out SIR (http://www.knufinke.de/sir/index_en.html) with some impulses from NoiseVault (http://www.noisevault.com), and they sound fantastic!

[NDEE]

Thanks dnortana for the info ;).

The combination of short reverb and convolution reverb seems interesting for a GPO mix, do you know if some demos of the GPO demo page have that combination?

Shazbot, thanks for the links!

NDEE

[dnortana]

NDEE,

I don't know about any of the demos on Gary's site. Maybe if one of the demo creators reads this thread, and used such a 'double' reverb technique on his piece, he/she can point it out for us.

I have the sense that this technique is fairly 'pro' level, for guys who really know what they're doing.

Trond