Sample impulse improvements

 

22/12/2016

 

Here are some things I’ve worked on outside of the nat sampler to further improve for overall better emulation.

 

 

1.Impulse pre post (linear phase) ringing from Convertors or src

I spent some time to find a very good filter for the use of of nebula libraries, the example below is of a very high ringing impulse response, The ringing is not seen in the hardware and can effect the sound quality. This also runs the risk of truncating pre-ringing because a limited offset.

bad-pre-post-impulse-riniging

Below we have a better filtered impulse example, this example is approximately 5 times smaller in it’s ringing artifacts! Because ringing is shorter, this in theory could effect the sound of the transient response, possibly giving better definition in the bass region and possibly less harsh, this is espicially true at lower sample rates. The following ringing length is 2 times shorter than one of  the best convertors on the market of course this is a trade off for other things yet Imo benifits its aplication. This is something In my most recent libraries.

redused-pre-post

 

2. overall stacked Phase and magnitude eliminated

Below we have a stacked instance eq. We can see a complete flip of phase in the top end and low frequency. due to stacking.

bad-phase

 

Below we have a non repeated phase or magnitude version of  stacked instances, with only 6 degrees of phase anomaly at 10khz. It’s debatable how much delay (phase) is audible to the human ear, however one thing that can’t be argued is the fact paralleling could cause some cancellation problems due to phase.

stacked-isolated-silk

A good example of band isolation can be seen in R-state eq, below we can see no roll offs from the overall magnitude of the eq.. notice the flatness around the bell, isolated eq portion-

3.Better harmonics

Below a artifact of chirping from deconvolution of harmonics, this is a typical frequency plot of incorrect chirping from deconvolution of harmonics. This was produced by increasing the input level.  Also incorrect ringing rising from the low band seen here too, which is discussed in point 4.

 

chirpping-harmonics

 

Below pushed hard Debugged saturation, with super low noise and transformer coloration and no chirping. Eliminating chirp is important as these chirps will be louder than the real harmonics, this could cause a significant build up over many tracks.good-harmonics

 

4. Hard truncation artifacts (windowing)

 

below we see hard truncation in the tail occurring over multiple instances

 

bad-messy-impuse-truncation

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The lower example illustrates ringing from very badly truncated impulse on frequency plot, this causes a filter effect and a ringing modulation to go up through the frequency plot.  Truncation through a very small impulse length can also cause a micro echo, which may sound more 3d, although this sounds interesting it is actually incorrect. Longer echo can be more audible, this is caused by long truncated impulse giving a bass echo. Bass echos occur because truncation is in latter part of the tail.

The echos can be seen also through a sweep in Izotope rx, a very fast sweep is excellent at finding echos. The echos can be seen in the two lines below the initial test sweep.Two echos exist because the example is using two truncated instances. Also the very faint blue haze is caused by noise on impulse. It’s possible to eliminte all these with appropraite techniques/

 

below a example of soft/or no truncated impulse. This reduces  or eliminate effect ringing through the band rising from the low frequency’s.soft-or-no-truncated-tails

Some of these techniques can be found in, Surge eq, Tube mid range eq, Silk eq v4, Dualtech passive eq v2, elc24 v3, 37j.