P821 MDN Tape— The Legendary Stephens 821 reborn

[kritikon]

You assume that all recordings on tape were pushed into saturation. It may surprise you to hear that not all recordists overloaded tape recorders. That seems to be something that is pushed around today by people who never used tape. A very widely held aim was to get clarity, which meant not distorting. Your compression and saturation is a feature of overloading tape. You've probably been around long enough to remember when digital recording started coming in? The really good tapes were advertised as being almost as clean and reproducible as digital. It was a reasonable pushback from the tape users and is still very true today. You can distort even top quality tape recording all you want but that doesn't mean you have to. Any tape recorder made can distort. I doubt you or I could hear any difference between a clean tape recording and a digital one.

And if this tape emu is so good an emu of a quality tape then it really should not be obvious unless you push it into overload emu.

[miloszz]

In and out both pegged at +18



the applied EQ curve does change a little with different tape speeds and formulations at least, but from what I could tell is not altered by input and output settings.

[bmanic]

Plugin Doctor advice:

When you want to see what a non-linear plugin does to audio, you can NOT use the linear frequency response graph for those purposes. You must use either the hammerstein graph or switch to sweep mode (select harmonic tab, set to swee and then tick the Fund. box).

Otherwise you will not see reality. The basic sweep mode and also hammerstein mode are limited as in what they can show. You will for instance not be able to get any time-relative things properly measured nor will you see what happens in the stereo image correctly.

I wish DDMF updated Plugin Doctor to a more thorough measuring tool. There are so many things missing.. unfortunately.

[JerGoertz]

Plugin Doctor advice:

When you want to see what a non-linear plugin does to audio, you can NOT use the linear frequency response graph for those purposes. You must use either the hammerstein graph or switch to sweep mode (select harmonic tab, set to swee and then tick the Fund. box).

Otherwise you will not see reality. The basic sweep mode and also hammerstein mode are limited as in what they can show. You will for instance not be able to get any time-relative things properly measured nor will you see what happens in the stereo image correctly.

I wish DDMF updated Plugin Doctor to a more thorough measuring tool. There are so many things missing.. unfortunately.

Does this mean that P821 does/doen't add saturation or other nonlinear effects? Or we can't tell from the information given so far?

[bmanic]

It does add a ton of non-linear stuff. You just can't measure them with PD if you use it's simplistic settings. I've noticed this with some other plugins as well. For instance Softube VCA compressor goes completely bonkers in PD yet it operates just fine in the real world.

[miloszz]

When you want to see what a non-linear plugin does to audio, you can NOT use the linear frequency response graph for those purposes. You must use either the hammerstein graph or switch to sweep mode (select harmonic tab, set to swee and then tick the Fund. box).

The Hammerstein graph shows a noise floor about 60db below the signal and no added harmonics (and the sine sweep shows no added harmonics), thus the images of the linear analysis to look at the EQ.

Here's the harmonic sweep with the input gain at +18db and 0db





Looks um... the same.

[miloszz]

Hammerstein at 0/0, +18/0, 0/+18, +18/+18

[jamcat]

So it has a more open sound to it and can define the elements better in the stereo image.

Gave the demo a whirl on the master bus. It does add a nice 3D effect to the sound. I checked with a mid/side plugin and it's adding 1dB to the sides and scooping the mids a bit.

I noticed an exaggerated stereo image with P821 MDN Tape, compared to Ampex ATR-102 or no plugin. It was the starkest difference to Ampex ATR-102 when both plugins were configured the same. It was definitely changed the audio quite a bit.

Based on what Vortifex said, it sounds like the P821 MDN Tape is doing some M/S stereo widening, which I guess is to create some 'wow' factor for the user. Maybe I'm off base here, but that seems a bit deceptive if that's what's going on, because a tape recorder shouldn't be doing that to the stereo image.

[miloszz]

And yes, you should not listen with your eyes or rely on Plugin Doctor, but my ears immediately heard the sweet sweet sound of snake oil and measurements don't appear to disagree.

[JerGoertz]

It does add a ton of non-linear stuff. You just can't measure them with PD if you use it's simplistic settings.

How would one measure them?

[bmanic]

I don't know. I haven't tried measuring it yet but I just commented due to experiencing oddities with other non-linear plugins in PD.

I have a bunch of my own test tones and some proprietary software that sometimes does a better job at unveiling what is going on.

You could just start by simply listening what is happening. Does it really sound like just some filtering? I highly doubt it. Then try to send it something like a very short 808 kick + noise burst.. or clap + embedded sine series. Then look at what changed. For checking what happens in the stereo field, you can first encode a stereo file into it's mid and side components and then crank them into separate instances of the plugin and listen to the difference (or just look at it in scope).

EDIT: And keep in mind that the wow/flutter emulation probably royally screws with plugin doctors ability to correctly compare input sample with output sample. This has happened to some of my own Reaktor designs when I was trying to debug what the hell it's doing.

What I'm trying to imply here is that measuring highly "wobbly" or "weird" plugins in PD is not at all straight forward.

[hey212]

If you look at the second to last page of the manual, you'll see that no one is credited for DSP.
https://www.pulsarmodular.com/wp-conten ... N_Dark.pdf

The new owner is credited with "Plugin Engine Design", but he is not a DSP engineer. That's kind of what I was getting at earlier, it's not clear that they're doing anything other than repackaging the original Pulsar Modular dev's DSP and tuning things by ear, which could be called "Plugin Engine Design".

To their credit, I haven't seen any claims that an engineer has done an actual component level circuit model of this tape machine, but it seems like that's being implied.

[ROTMetro]

I noticed an exaggerated stereo image with P821 MDN Tape, compared to Ampex ATR-102 or no plugin. It was the starkest difference to Ampex ATR-102 when both plugins were configured the same. It was definitely changed the audio quite a bit.

Based on what Vortifex said, it sounds like the P821 MDN Tape is doing some M/S stereo widening, which I guess is to create some 'wow' factor for the user. Maybe I'm off base here, but that seems a bit deceptive if that's what's going on, because a tape recorder shouldn't be doing that to the stereo image.

Blue button at the top left.

[rectifried]

this forum is always... strange. PM has a new owner for 6 years.. and the orig guy made the synth? hence Pulsar "modular"

soooo who made all the plugins since.
like I said
strange forum

[P900]

Strange that users want to believe readings from Plugin Dr. and not what their ears are hearing! There is saturation and there is compression. It is not our problem if Plugin Dr. is not able to register it.
But now the main question that worries me is, why would you be in the audio business if you are not able to hear what P821 is doing! That is the question that one should be investigating.