Here's another for comparison. This is Bootsie's TesslaPRO.

Here's another: FerricTDS, Bootsie's predecessor to TesslaPRO.  

Here's Ozone 4's exciter in Tape mode:

I've always liked Ozone 3's exciter better and still use it when I want to dirty up vocals:

OK, one more just for grins...


This one's not a "tape sim", it's just a plain old unpretentious distortion plugin: Shred. 

Bit inspired me to do the same.

Here's Logic's Native Tape Delay plug-in w/ the delay turned off and the tape saturation on.





And Waves Kramer:








Pretty similar indeed. But it's not just a matter of frequencies, is it... I'm wondering how the source material interacts w/ those harmonics, how quickly they're created in reaction to actual music. Then there's the compression.

I'll try and do a few tests w/ McDSP's tape emulation in Pro Tools tomorrow - usually when switching between the various tape models, you can actually hear a noticeable difference, even w/o touching the other parameters. Though I guess most of it has to do w/ where the low cut happens and the bump in the EQ curve at the cutoff frequency.

But it's not just a matter of frequencies, is it...

Correct. I think. Tape responds differently to transients versus steady-state signals, so any real tape simulator would presumably do the same. 


It would be challenging to devise a repeatable test for that behavior, though. 

Thanks Bit for sharing the additional info.
I agree that you are only getting a limited idea what some of these plugins are actually doing with the simple sine wave.
It just gives sort of a basis for taking it out further.

It would be really amazing to explore what is happening in a more complex series of waveforms like a bass guitar or even on a full mix. 

The adventure continues ;^)

bit, did you do any sweep tones in your analysis? It's important to do those and observe the spectrum to find out if any of the plugins are aliasing. If your test tone is rising in pitch and any of the harmonics are descending, then you've got aliasing. ReelBus looks like it might be a candidate.

So, even though the plug-in isn't available as a VST for windows, I thought it might be relevant to mention it in this thread, because, after all, it's about tape simulation and how it affects audio.

One thing I really dig about AC202 is that it discards the tape machine looks and controls to actually focus on what happens to your signal - it provides you w/ a frequency reference for each modeled tape, roll off and head bump, which of course you can alter, a "release" control, which determines how quickly the plug-in recovers from saturation state and returns to linear state. 

Then depending on tape type and playback speed, the dynamic range of the material will be affected, and so on... 

I guess other plug-ins do basically the same thing but they're not always as eloquent about what goes on w/ your signal and often prefer to use a single vague term like "warmth" to describe what really is an accumulation of filters and processes.

Here's 2 screenshots from the AC202 manual with a graph of the basic curve for 2 different playback heads (Studer and Otari). As you can imagine, the plug-in already has a quite audible effect just by enabling it, depending on the playback head you select and even before you start tweaking and adding distortion...