Compression and saturation, in what order?

[bobby yarrow]

Well, lookit, while DSP technology is completely unknown to me, and while I don't doubt that a+b is the same as b+a, in all practical applications the order of effects like reverb, delay, and eq matter a lot. If you're describing a mathmatical claim about the properties of perfect processes in a theorhetical (but practically unobtainable) signal path, fine. Point is, anyone wondering whether it matters in practice should know that delay before reverb sounds quite different than reverb before delay. This is true for every class of effect.

EQ pre or post reverb is a huge difference. For one thing, nobody runs their reverb 100% wet. For another, in hardware at least, reverbs tend to be resonant at certain frequencies more than others. If you attenuate those frequencies pre-send, the reverb is going to produce a balanced return at a certain db. If you attenuate those frequencies after the send, you're going to end up with a quieter return, as much of the signal coming out of the reverb at that same db is loaded with the resonance we're trying to remove.

And, as far as compression pre or post distortion, we agree it matters a lot. Unless you've got so much distortion on the track that there's little left to compress, it sounds pretty different.

[Krakatau]

I agree at the point this is much more of a "D.I.Y. thread for young apprentice"

And it's quite true that in such level of practice, these technical aspects does rarely make sense (still...)

[tahome]

I won't argue with you about compression and distortion as these are non-linear processes.

As for delay, reverb and eq: in practice, there can be a difference because you're usually not running your sound source through a reverb or delay that are chained one after the other. IOW your signal path is usually more complex than just a serial chain.

Also, reverbs can in fact contain modulation which makes the whole process non-linear. In that case it does indeed matter if the EQ comes before or after the reverb.

So yes, I agree that in practice this might make a difference because your setup is more complex. Still, even in practice, for a serial routing of linear effects it doesn't make a difference.

I don't remember how this line of thought started, but I guess it's not very relevant to the discussion anyway so we might as well leave it at that...

--th

[Krakatau]

no offence men, you add some very interesting comments...

There a few definitions i'd like to understand better :

What did meant by :

- Recursive

- IIR ( inverted impulse response...huh...)

____

It suggest me something basically similar to some process includes into Impulse responses, ( but i can't get it yet )

[.jon]

In an insert chain, you are either applying reverb to the original signal+delayed repeats, or creating delayed repeats of the reverbed signal... and that does matter both in theory and practise.

[pekadan]

I agree, my initial question has pretty much been answered already, but I'm definitely still following the discussion with interest. Do carry on!

[tahome]

"Recursive" basically means "involving a feedback path".

"IIR" is an "infinite impulse response" filter. IIRs require a recursive structure - the output from the filter is (usually reduced in volume) fed back into its input.

This causes any impulse entering into the filter to create an output that becomes smaller over time, but never vanish -> hence infinite impulse responde.

A FIR ("finite impulse response") filter is one that doesn't have a feedback path. If you feed an impulse into that sort of filter its output will stop exactly after a number of samples equal to the filter length.

--th

[tahome]

In an insert chain, you are either applying reverb to the original signal+delayed repeats, or creating delayed repeats of the reverbed signal... and that does matter both in theory and practise.

No it is in exactly this case that it does not matter.

In other words: If you have the exact same signal path, a reverberated delay is the same as a delayed reverb.

--th

[Krakatau]

In an insert chain, you are either applying reverb to the original signal+delayed repeats, or creating delayed repeats of the reverbed signal... and that does matter both in theory and practise.

No it is in exactly this case that it does not matter.

In other words: If you have the exact same signal path, a reverberated delay is the same as a delayed reverb.

--th

That's all the HUGE point : who was thirst :


THE CHICKEN OR THE EGG?





sarcastically yours... !

[bobby yarrow]

Not to belabour the point, th, as I think we understand each other, but it's not that my setup is particularly complex or anything. In application, it always matters, even in the simplest signal chain, as I think I demonstrated with my 1-track, 2-plugin example.

My point is, in application, the linear vs. non-linear distinction isn't something engineers should worry about. In application, the order of effects always matters.

[tahome]

It doesn't matter whether or not the chicken or the egg was first... they both end up at KFC.

Anyway... let's use a simpler example then: if you have two filters in a serial chain, ie. one after another.

Let's also assume this is a high pass and a low pass, where the high pass is set at a frequency of 1000Hz and the low pass is set at a frequency of 5000 Hz, both have a Q factor of 1.0.

Now tell me, what will happen to the signal that passes through this signal path, and how will the path

Signal -> LP -> HP -> out

be different from the path

Signal -> HP -> LP -> out

?

Is there a difference, and if so, why.

--th

[Krakatau]

It doesn't matter whether or not the chicken or the egg was first... they both end up at KFC.

What the hell makes you think my irrelevant comment was targeting you ?




( too easy !!!!!!!!!!)

[Krakatau]

It doesn't matter whether or not the chicken or the egg was first... they both end up at KFC.

Anyway... let's use a simpler example then: if you have two filters in a serial chain, ie. one after another.

Let's also assume this is a high pass and a low pass, where the high pass is set at a frequency of 1000Hz and the low pass is set at a frequency of 5000 Hz, both have a Q factor of 1.0.

Now tell me, what will happen to the signal that passes through this signal path, and how will the path

Signal -> LP -> HP -> out

be different from the path

Signal -> HP -> LP -> out



?

Is there a difference, and if so, why.

--th

In practice ( and obviously only in practice ), i can tell by experience you'll often have to deal with some broadband noise coming from one effect module or another and in the case in would make sense to choose an appropriate order to avoid the problem £!

[.jon]

You're of course correct with the filters, but I thought delays would be different.

Well I hate being wrong, but I did try it in practice and though there is a minor difference, it must be related to something else than my theory.

damn

live and learn, thanks tahome!

[tahome]

Well, I must admit that it does sound highly counter intuitive.

But if you think of it, a delay isn't different from a filter, and neither is a reverb (otherwise all the IR reverbs wouldn't work - they're based on the same principle as a filter/EQ!).

A delay can be seen as a filter with one filter tap being one and the others being zero. It's just a very simple filter, nothing else. A reverb can be seen as a very long filter with lots of apparently random taps.

Hence the same rules apply.

--th