[LAD] Floating point Denormals: C++ and Waf

Robin Gareus robin at gareus.org
Thu Aug 2 21:16:50 UTC 2012

On 08/02/2012 10:56 PM, Harry van Haaren wrote:
> Thanks all for the replies, I've certainly learnt a lot.
> On Thu, Aug 2, 2012 at 9:11 PM, Tim Goetze <tim at quitte.de> wrote:
>> I think it's almost always a better idea to add an inaudible DC offset
>> or a square wave at the block interval or at Nyquist
> How small is inaudible? Or better yet, how small is way beyond inaudible,
> but enough to eliminate any denormals?

1e-20 ( ~= signal at -400db ) should be inaudible enough.

Denormals start < 1e-31 (~ -620db).

> The other problem is locating exactly where the problem exists: I'm using
> Faust <http://faust.grame.fr/> to generate the reverb DSP code, so
> injecting DC offset would involve me tinkering with the reverb algorithm.
> I'd prefer leave it alone, but the outputs of the reverb can be DC-offseted
> easily. I don't think that would be enough... since the denormals could /
> would also exist internally in the reverb algo?

You should to add it to each sample on the input, before the signal
enters the effect.


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