>>Dietz suggested using a negative predelay to integrate the VSL recordings' early reflections with the Altiverb tail, and that works really well a lot of the time.>>

Sorry Nick, sorry Dietz,

but what do I have to understand when speaking of an 'negative predelay'?

What is negative - is the phase inversed? Is the Delaytime set to negative values (hmmm, how to do that?)

Would you mind to describe that a bit more clearly?

Thanks,
Steff

Nothing like that! It just starts the reverb later, I think, so you get a transparent seam between the sample and the space.

I don't use it on everything, but it can be effective.

Steff,

Pre-Delay acts on the Reverb Tail. (Typically Pre-Delay is handled by separate circuitary or its software equivalent in standard reverb units).

The simplest way of thinking of this is that Positive Pre-Delay works by offsetting (delaying) the WET part of the signal whereas Negative Pre Delay acts on the DRY part of the signal.

I wish we could post pictures on this site - this next bit needs a diagram!

There is a very subtle difference between how Pre-delay works (and is implemented) in 'Standard' Reverbs and 'Convolving' Reverbs. In Convolving Reverbs the Dry signal is re-sampled (complex conjucated math 1-j and 1+j etc.) This means that the post convolved sound image contains both the Dry and the Wet. Pre-delay 'negative or positive' then acts by emphasing or de-emphasing the tail element.

In Altiverb you can add more (Pure) DRY to the mix --- this is not increasing what is sent to the Reverb but simply adding more dry signal to the mix.

In Space Designer Emagic have added additional 'circuitary' which effectively splits the Pure Reverb and the Pure Signal (It really is wrong to think of the terms Wet and Dry post convolution) - this is more akin to the standard Wet/Dry balance seen in most reverbs - this really come into effect when you use Space Designer in Synthetic IR mode.

David T,

WAVES S1 and Altiverb (or Space Designer for that matter) dont seem to want to work that well together. I agree with your findings that on large spaces you get a kind of MUSH in the middle. [NOTE - in reality you would expect some loss of Imaging in the upper frequencies, more so in multi-faceted spaces, naturally caused by subtractive phase destruction]

M-S and M-S EQ techniques might give you some improvements.

However when I changed out the S1 for the MDA Imager (FREE VST PLUG-IN that works with the VST/AU Wrapper in OSX) I got the clarity that I needed.

tattie

Tattie -

the "negative pre-delay" of AltiVerb just shortens the initial phase of the IR, it has nothing to do with the dry signal per se.

/Dietz - Vienna Symphonic Library

Hmmm!, [:D] I thought that is what I said.


"This means that the post convolved sound image contains both the Dry and the Wet. Pre-delay 'negative or positive' then acts by emphasing or de-emphasing the tail element"

It will be hard to break the habit of talking about wet and dry. In convoluting Reverbs Wet and Dry are really meaningless, in the classic sense.

tattie
[/code]

In Altiverb the terms have the classic meaning. You can adjust the dry level, and in fact there's a button to mute it - which is what I use, since like most mortals I need to share Altiverbs using a send/return set-up.