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LSR Audio Plug-ins

Dynamics & Tube Emulation Plug-ins For Mac & PC
Published October 2012
By Sam Inglis

The virtual vintage front panels of LSR Audio's plug-ins conceal processors with plenty of personality.

LSR Audio are a new plug-in development company led by developer Emmanuel Dubecq, whose products echo the 'boutique' styling of some modern hardware manufacturers. They're not intended as clones of vintage equipment, and in some cases what they do would be difficult or impossible to achieve in the analogue domain, but at the same time, the overall vibe they are seeking is clearly based around tube warmth and distortion.

At present, the LSR range falls into two categories. They offer a number of Single Knob plug-ins designed to achieve one effect with maximum ease of use; these are described in the 'Single Knob Series') box. The technology underlying those plug-ins, however, is also made available in four more sophisticated dynamics processors called WARMultipress, COMPrime, TUBEnhance and DynamicsDetail, all available in VST, Audio Units and RTAS formats for both Mac and PC. They need to be authorised online, but if your studio computer isn't connected to the Internet, or you wish to use them on multiple machines, you can have the authorisation files written to a USB pen drive instead of the system drive.

Prime Numbers

At least on the outside, COMPrime is the most familiar and conventional of these plug-ins.LSR Audio Plug-ins It's a modelled tube compressor with the usual attack, release, threshold and make-up gain controls, plus a Drive dial which adds controlled amounts of simulated tube distortion. There's a low-cut filter in the side-chain to allow you to shape the extent to which the compression is driven by low-frequency elements in the signal, and a large VU meter, which can display either gain reduction or output level.

Despite its relative simplicity, COMPrime took me a while to get used to, partly because there's no manual, and partly because of a couple of quirks in its design. Although its compression algorithm is described as 'progressive', my impression was that it behaves more like a hard-knee than a soft-knee design, and I also found that the same ratios and attack and release times I would typically use with other compressors seemed much more 'grabby' here. Finally, despite its vintage looks, the meter seems to behave much more like a digital peak meter than an analogue VU meter. The consequence is that even with a modest ratio such as 1.5:1, as you turn the threshold level down, nothing whatsoever happens for quite a while, then suddenly the needle starts to leap about all over the place! (I also encountered graphical glitches whereby dials weren't rendered properly.)

Initially, then, I found it hard to achieve a smooth levelling effect, although things improved a lot once I experimented with much higher attack and release times than I'd usually employ. Even then, it's very much the kind of compressor that jumps in your face and says "Hello! I'm doing some compression right now!” The tube distortion, meanwhile, offers a decent gradation from subtle warmth through to obvious grit, although I found that with dynamic sources, such as vocals, I had to be careful lest peaks became too harsh-sounding. For soft sources, I would also have liked more than the maximum 6dB make-up gain on offer.

Once I'd got my head around COMPrime's unusual response, I found it quite usable, if rather unlike most of the modelled vintage tube compressors I've encountered. The likes of Softube's Tube-Tech CL1B or Universal Audio's Fairchild 670, for instance, keep their velvet gloves on even when compressing quite hard. COMPrime tends to be rather more frisky, and I found I needed to put a lot more care into setting it up properly if I didn't want the compression to become too obvious.

Pressing Engagement

WARMultipress is the most complex of LSR Audio's designs. Clearly intended for mastering, it's a multi-band compressor that also incorporates modelled tube saturation and tape simulation. The input signal is split into three frequency bands, each of which has its own bank of compressor controls comprising attack and release time, threshold level and ratio — which, curiously, is calibrated from zero to 100 percent, rather than from 1:1 to infinity:1. Each band also allows you to adjust input and output gain. The remaining controls are global, and include a hard/soft knee switch which applies to all three compressors, a simple on/off switch for the tape emulation, and Drive and Shape controls for the tube saturation.LSR Audio Plug-ins

To the right of the compressor controls is a square display window. This can show static representations of either the compression or the tube saturation curves, but its main function is as a scrolling waveform display that shows the actions of the compressor and tube simulation in real time. I found this display quite cryptic at first and, unfortunately, the brief PDF manual doesn't help much.

What is clear is that the waveform scrolls from right to left, behind a rather annoying piece of reflective virtual glass! Two horizontal lines in each band represent the threshold and the ratio, although how exactly these relate to their respective settings isn't obvious. Waveform peaks sometimes turn orange or blue depending on the compressor settings, and after a while, I realised that this represents net gain change after make-up gain. In other words, if there's a level difference between the input and output signal, it's represented as blue where gain reduction has taken place, and orange where the gain has been increased.

It's nice to have this real-time display of what WARMultipress is doing, but I'm not sure it quite hits the mark for me. Although the display window isn't tiny, I still found it uncomfortably cramped, and for mastering applications, in particular, I feel that the metering would benefit greatly from beng more detailed and numerically calibrated. As it is, there's no scale visible at all, so you have no idea how much blue corresponds to how many dB of gain reduction. A set of large meters that simply displayed RMS and peak levels and gain reduction against a numeric scale would be a very welcome addition.

Once I'd figured out how to interpret the display, I began to get decent sonic results from WARMultipress, although, again, it has its share of quirks. I found I needed to ramp up the input gain to get any compression at all going on the highest frequency band, and once I'd done that, it was even harder to interpret the metering, because the output level setting needed to compensate for this simply turned almost the entire waveform blue. The main reason why I sometimes use multi-band compressors at mixdown is to compensate for any issues with the overall tonality of the mix — most often to bring sunken mid-range frequencies a little more forward — and WARMultipress did a pretty decent job in this role. On suitable material, moreover, the modelled tube saturation adds a pleasant warmth and a free boost in apparent loudness, though it's perhaps a shame that it can't be applied to different levels across each band. I was less impressed by the tape simulation, which appears to simply switch in a fixed EQ curve, but it's hard to perform a fair A/B, as it drops the level noticeably.

Up The Tubes

Probably my favourite plug-in in the LSR Audio range is TUBEnhance, which is a fairly simple but very effective 'wamer-upper'. The input signal is split into high- and low-frequency bands at a user-defined crossover point. A single Balance control determines how the amount of tube drive is apportioned between these bands, and, once again, there's a Shape control that sets the non-linearity of the overdrive. Finally, the large Drive control is augmented by a small red button, which, when active, multiplies the Drive setting by 10 for serious crunch.LSR Audio Plug-ins

With the x10 button disengaged, the Drive control covers a nice range of subtle effects, and is often very usable even at the 100 percent setting. On a drum bus, for instance, I found I could turn the Drive up full without things getting unpleasantly grotty, while the Balance control makes it easy to steer a path between muddy or boomy on the one hand, and gritty or crispy on the other. Likewise, I really liked TUBEnhance as a way of warming up a DI'd acoustic guitar track: it was much more subtle than a typical amp simulator, but added richness and sparkle to the sound without any hint of harshness. In fact, for some of these subtle applications I actually found it easier to get the sound I wanted with TUBEnhance than with Sound Toys' Decapitator, my all-time favourite distortion plug-in — high praise indeed! That said, Decapitator is much more versatile, offering a variety of styles of distortion, and (to my ears) TUBEnhance can't compete when you enter the realms of obvious crunch and fuzz.

The Devils In DynamicsDetail

I also have a lot of time for LSR Audio's take on the transient shaper concept. DynamicsDetail offers a simple but rather unusual control set which allows you to determine how it decides what is an 'attack' and what is a 'sustain'. In essence, it computes two RMS levels over a short and a longer time window (both of which are user-defined), then compares them. Since it is working with the difference between these two values, rather than the absolute level, it is able to detect transients regardless of the actual signal level. Simple sliders then allow you to rebalance the levels of the attack and release phases. LSR Audio Plug-ins

It took me a few minutes to get a feel for how changing the time constants modifies the dynamic response, but, broadly speaking, it seems that the more difference between the Fast and Slow values, the more sensitive DynamicsDetail is to transients. In situations where you want to boost the sustain rather than the transient, it's not always easy to shape exactly the duration of this sustain, but careful juggling of the two controls does make it possible. I also found that by reversing the Fast and Slow values and ramping up the sustain, I could get some interesting and very useful effects on drum tracks, whereby the 'meat' of the drum sound was brought forward without lifting either the initial transient or the ring of the snare. In more conventional use, the amount by which attacks can be lifted tends to top out around 6dB — which is plenty for most purposes — while the available sustain reduction is much more drastic, almost acting like a gate at extreme settings. Overall, I liked this plug-in a lot: it does gentle transient shaping well, and the unique control system opens up some possibilities I don't recall encountering elsewhere.

DynamicsDetail and WARMultipress provide good examples of the lateral thinking that underlies the LSR Audio range. When I first installed them, I expected these to be conventional emulations of classic and vintage hardware, but the more I got to use them, the more I realised that they have a personality of their own. In the case of WARMultipress and especially COMPrime, that personality can be a bit temperamental, and it's a shame there isn't better documentation to help out, but if you're not afraid to use your ears rather than your eyes to set things up, they're all capable of producing good-quality results, not to mention the odd surprise! At the price, I think that DynamicsDetail and TUBEnhance, in particular, are good buys.  

The Single Knob Series

LSR Audio's Single Knob series of plug-ins will probably stir a few memories in anyone who has a passing familiarity with the Waves plug-in catalogue, and in particular, with that company's OneKnob processors, which I reviewed in SOS June 2011 (/sos/jun11/articles/one-knob.htm). Just like their Waves counterparts, the Single Knob plug-ins each provide precisely one control, but behind the scenes, this usually adjusts multiple parameters, so there's often more going on than meets the eye. Just as in the Waves effects, the underlying processing is derived from LSR's 'full strength' plug-ins, so although you compromise on controllability, the sound quality should be just as good. LSR Audio Plug-ins

SK_Bright and SK_Drive are both derivatives of TUBEnhance. The former, in essence, splits the input signal into two bands, leaves the lower one alone, and applies modelled tube drive to the upper band, the aim being to add harmonics and create the impression of brightness without having to use EQ. The latter is a full-band warmth and distortion effect. SK_Bass is, in some ways, the mirror image of SK_Bright, adding controlled harmonic distortion to the lower end of the signal while slightly attenuating the low bass, in order to enhance the psychoacoustic impression of bass without eating up too much headroom at the low end. Finally, SK_Dynamics is derived from the DynamicsDetail plug-in, and lets you move its single control clockwise to apply a kind of 'expansion-cum-transient enhancement', or anti-clockwise for fairly obvious compression.

One key difference between these plug-ins and Waves' offerings is price: these retail at just $9 each, with the exception of SK_Dynamics, which is $16. By contrast, buying a significant number of Waves OneKnob plug-ins would set you back a couple of hundred dollars. At this low price, the concept makes a lot more sense to me, although even then I'd be more tempted to shell out for the full versions of the LSR plug-ins, which are hardly overpriced. I wasn't awfully keen on SK_Dynamics — although it's distilled from DynamicsDetail, it didn't seem to capture the qualities of it that I liked — and SK_Bright was a bit lacking in subtlety for my taste. By contrast, I found SK_Drive very useful, as it covers a slightly different range of distortion to that available in TUBEnhance, and SK_Bass is also a handy plug-in which couldn't easily be recreated using the full LSR range. Either way, at this price you only need find a couple of uses for these plug-ins to justify the very small outlay.

Published October 2012