Antares Microphone Modeller

Antares' latest plug‑in can, it is claimed, alter a recording made with one model of mic so that it sounds as if it was done with another. But can you really make any budget mic sound like a high‑end classic? Paul White investigates.

Physical modelling is getting pretty pervasive these days, and now it's moved beyond simulating analogue equipment, guitar amps and old synths to emulating classic (and not‑so‑classic) microphones. Antares' Microphone Modeler isn't the first product to perform microphone modelling — Roland have included it in their VS‑series digital workstations for some time — but it is the first TDM plug‑in designed for the purpose. Of course, much of the difference between microphones lies in their differing frequency responses, an issue which can be addressed to some extent with sympathetic EQ: indeed, I'm unsure as to how much Antares' program relies on true modelling and to what extent it is merely a re‑equaliser. Ultimately, though, it doesn't really matter — all that's important is the result.

Currently, Microphone Modeler is only available as a TDM plug‑in for Pro Tools systems. However, Antares' Auto‑Tune started off the same way and has since been produced as a low‑cost VST plug‑in, so perhaps MM will go the same way later.

The idea behind the plug‑in is that you can process a recording made using any of the microphones in Microphone Modeler's library to make it sound as though it was recorded using any of the other mics in the library. Every microphone has its own characteristic frequency‑response curve, so Microphone Modeler first compensates for the characteristics of the original mic, then imposes the curve of the target microphone. However, Antares take the process rather further by including the characteristics of low‑cut switches where fitted; with some models, you can also opt to have the windscreen on or off. Then there's distance to consider. Used close up, a cardioid mic will exhibit a proximity effect resulting in a degree of bass boost which varies from model to model. To emulate this, Antares have added a virtual distance parameter, and for good measure, they've also included a modelled tube mic amp that any of the mics can be processed through.

It all sounds too good to be true. Can you really make any old mic sound like a top‑end studio classic? Clearly there are limits, and Antares are the first to point this out. Firstly, if the mic you use for recording rolls off above, say, 12kHz, no amount of EQ or other processing is going to recreate the top end that a capacitor mic with a 22kHz frequency response has. Furthermore, different mics have different off‑axis frequency responses, a factor that also affects the sound in ways that depend on the room acoustics and how close the mic was to the source in the first place.

Even so, if the technology enables you to treat a new recording so that it closely matches existing material made with another microphone, then it's clearly a valuable tool. Equally, if you can make an existing recording sound more 'appropriate', then accuracy is not necessarily important.

The Interface

Microphone Modeler can compensate for the basic frequency‑response characteristics of a given mic, such as Microtech Gefell's UMT800 shown, but also for proximity effect and for the effects of low‑cut and polar‑pattern switches.

The screen shot of the interface shows how simple Microphone Modeler is to use. The left‑hand side of the virtual panel shows the input mic (the one used for the original recording), while the right‑hand or output side is used to select the mic you wish you'd used. Both the input and output sections have separate gain controls (the input also has a level meter) and both have their own virtual knobs for setting the microphone distance from the source. The desired source and destination microphones (or a flat, bypass setting) are selected from pull‑down menus, and there are further parameter windows for selecting the low‑cut and polar pattern setting of the mic where appropriate. Mics modelled with a windscreen fitted have a W after their name. Selecting low‑cut for the source mic will compensate for the low‑cut filter originally used, so it will actually bring about a bass boost. Though the polar pattern setting won't let you turn a cardioid mic into an omni in such a way that you can hear behind it, it will mimic the changes in frequency response that occur when a new pattern is selected on any of the multi‑pattern destination mics.

A horizontal slider controls the amount of tube saturation, the premise being that this models the subtle distortion characteristics of a high‑quality tube mic amp. Both the input gain control and the Drive affect the level of 'tube coloration', but there's only 10dB of tube drive available, so if you're working with a signal that's more than 10dB below DFS, you may need to normalise within your main audio program before you can impose any tube coloration on it. As the drive stage can add gain, the output fader offers attenuation only.

Directly above the Tube fader is a pair of buttons, labelled Bass and Treble, in a box called Preserve Source. This section splits the audio frequency into two bands — the idea being that if you have a sound that already has a nice low end, you can opt to preserve that and apply the new mic model only to the higher frequencies. Conversely, you can keep the high end of the original signal and replace just the low end with that of a different mic. This is clearly not something you could do in the real world, but if it creates a sound that works then it's more than justified.

The mic models themselves are stored as separate files which, in the case of Mac users, are located within the Preferences folder in the System folder. New models may be added directly from the Antares web site as they become available, and MM is supplied with plenty of popular mic models already loaded. These include 11 AKG models (C1000 to C12A), an Alesis model, nine Audio Technicas, four Audix, a B&K 4007, a couple of Beyerdynamics (though oddly no MC740), three BLUE models, a Brauner VM1 and six CADs. The range continues with examples from Coles, Earthworks, AEA, EV, Groove Tubes, Lawson, Manley, Microtech and of course a fine selection of Neumanns. The menu is rounded out with mics from Oktava (though no MK219), RCA, Rode, Royer, four of Sennheiser's dynamic classics, the best known of the Shure dynamic and capacitor ranges, and a selection of Sony models before ending with a Telefunken U47 (a vintage version of the Neumann U47).

The manual makes it quite clear that although these are the actual mics modelled, there is no relationship or endorsement arrangement between Antares and any of these companies: the names are listed purely to show which mics have been modelled.

Like any TDM plug‑in, Microphone Modeler can be automated, though there are few applications for automation in this instance, unless you feel you have to move the virtual mic back and forth to simulate some imagined mic technique of the original performer. The manual also admits that some automation routines may come unstuck as the mic models are recognised by their position in the library list, so if you add a new model the position of the mic originally chosen may be different.

Using Microphone Modeler

Installing the Microphone Modeler plug‑in is easy enough, and the usual key disk protection has been replaced by the currently popular 'challenge and response' system. The program generates a string of eight words which you then send back to Antares or their distributor to receive your authorisation code.

Once installed, the plug‑in is available within your usual list of TDM plug‑ins; if you haven't yet authorised it, you have the opportunity to run the program for 12 days unauthorised before it puts its foot down and refuses to go any further. Unless you reformat or replace the authorised drive, you shouldn't need to change the authorisation code once issued.

There's only one window for the plug‑in, and as explained earlier this is pretty straightforward. Mostly, you just input the mic you used, or its nearest equivalent if the exact model isn't in the list, and set the distance the mic was used at; if the mic had its low‑cut filter switched in you need to do this on Microphone Modeler also. Then you choose the mic you want to emulate, and the sound is transformed in real time. What's more, the results are pretty convincing, providing your original mic has a halfway‑decent frequency response. I would imagine that turning a source capacitor mic into a virtual dynamic mic would be more accurate than the converse, but it's still surprising how authentic the process sounds, even when using something like an SM58 for the source recording. Subtle differences between the various capacitor mic models are more or less obvious depending on the source material, while the dynamic models have that solid, rounded sound characteristic of real dynamic mics.

I don't think a process like this can ever be expected to exactly reproduce the results that the real mics would, but the closer the characteristics of the source and destination models, the more transparent the conversion. Even with quite different microphones, you get something better than a first‑order approximation, and if you're working on an existing recording and need to match an overdub or drop‑in with the sound of the mic used on the original recording the chances are that Microphone Modeler will get you close enough that nobody will notice.

The tube amp model also adds a useful degree of warmth without over‑processing the sound, and though it isn't based on specific mic or preamp models it can often be used to fine‑tune the sound of a recording to more closely match the original, especially if you need to add a little extra warmth or thickness. As you add more 'tube' drive, a little valve icon glows brighter.

Conclusion

Whether you need this plug‑in or not depends to some extent on how much 'patching and matching' work you have to do and on your approach to sound creation and mixing, but it's certainly a clever and well‑thought‑out piece of software. Microphone Modeler isn't magic and it does have its limitations, but it's a powerful tool, both for changing the character of a recorded sound for artistic reasons, and for matching sounds recorded with different mics or in different environments.