Technology

MCDSP ML8000 Advanced Limiter

Discrete multiband and wideband units in a single GUI
Controls for the ML8000’s multiband limiter are positioned in the bottom half of the GUI’s center and in the bottom-left corner.

The McDSP ML8000 Advanced Limiter incorporates two completely independent stages of limiting: Its 8-band limiter is followed in the audio path by a wideband master limiter. The plug-in’s proposed primary application is mastering, but it’s also extremely well-suited to use on buses and individual tracks. Wide-ranging Knee controls—one for each limiter stage—adapt the processor to use as a limiter or compressor, or both simultaneously.

The ML8000 is available in AAX (Native and DSP), AU and VST formats, and in both mono and stereo configurations. I reviewed the AU version in Digital Performer 9.01, using an 8-core Mac Pro running OS X 10.9.5.

THE PLOT THICKENS

At the top-center of the GUI is an interactive response plot that shows frequencies (along the horizontal axis) vs. gain (vertical axis). The plot allows some control adjustments and graphically depicts the ML8000’s multiband action. Color-coded shadings show input gain for each band, and a white curve moves up and down to reflect changes in in-band gain due to processing (see image above).

You can drag vertical lines left or right to adjust the bandwidth of each of the multiband limiter’s eight bands. (The multiband limiter eschews using crossovers to split up bands for processing, instead using active processing to minimize phase distortion between adjacent bands.) Each band also has a gain “dot,” which you can drag up or down to respectively boost or cut input gain for the band. Click on two small buttons below the response plot to apply a highpass and lowpass filter to bands 1 and 8 before dynamics processing. The filters use the bands’ respective crossover points for their corner frequencies and employ 12dB/octave slopes.

Below the response plot lie the majority of controls for the multiband limiter. Controls for each band include a gain fader, threshold control (which sets the output ceiling, or maximum output level), and bypass, link, solo and key-listen buttons. The threshold level is adjusted by vertically dragging an orange arrow positioned alongside the band’s input-level meter (which shows signal level after the band’s input-gain fader), providing an intuitive visual reference as to how the two identically calibrated levels compare. Any combination of bands can be soloed: Rather than monitoring the soloed frequency bands’ spectra, soloing deactivates processing in bands that are not soloed. (All control settings are retained for subsequent reactivation.)

Clicking a key-listen button monitors the corresponding band’s input signal post-fader and before dynamics processing. Each band can be linked to any combination of other bands: Click on the M (Master Link Enable) button for one of the bands to select it as the gain, threshold and bypass controller for all other bands that have their L (Link Enable) button activated. Fortunately, control offsets are maintained after linking, and each linked band can have its own gain and threshold controls adjusted independent of the master band; with this design, you don’t have to defeat the link function temporarily simply to fine-tune control offsets between bands. Nice! You can automate all controls for the ML8000, and linked bands follow the link master’s automation.

Global controls for the multiband limiter (situated in the lower-left corner of the GUI) include Release (time), Knee, Bypass and global Character Mode and Focus buttons that affect how the multiband limiter detects and acts on input signals. Cycling through the six Character modes (Clean, Soft, Smart, Dynamic, Loud and Crush) progressively changes the multiband limiter’s action from transparent and pristine (Clean) to loud and pumping with some signal distortion (Crush).

There are also three Focus modes: Fixed (which elicits standard active processing), Vari-1 (slightly narrows the bell-curve shape for each band), and Vari-2 (provides the most narrow bell–curve shape for each band). Because each mode’s action is further influenced by your Knee setting, you can fashion a huge variety of dynamic responses to tracks. A convenient Snap button is also provided; clicking on it sets all Threshold controls to the approximate signal level each band’s input meter shows.

The ML8000’s second processing stage contains a master limiter that uses the same algorithm as the company’s ML4000 Limiter plug-in. The master limiter employs 1 ms of fixed lookahead detection to minimize distortion. Controls for this limiter (situated in the top-left corner of the GUI) include Threshold, Ceiling (maximum output level), Release (time; adjustable from 1 ms to 5 seconds), Knee, Bypass and Character Mode selector (which offers the same six Character Modes as the multiband limiter and adjusts how the master limiter reacts to signal peaks).

On the right side of the GUI are left- and right-channel meters that show the master limiter’s input (post-multiband limiter) and output levels, along with a singular gain-reduction meter and clip LEDs.

CRUNCH TIME

I got very good results processing a full mix with the ML8000, using a very hard knee and fast release times in Clean mode for both limiter stages. Using the multiband limiter, I could transparently control bass level, sibilance and other excess spectral energy. For example, I could boost the input gain in bass bands and then limit them to create a bigger yet tighter bottom. The master limiter section very transparently increased the mix’s perceived loudness by reducing peak levels overall.

All that said, I wished the ML8000’s control set enabled the more discriminating processing needed to execute surgical mastering techniques. Because the ML8000 lacks freely programmable internal sidechain filters and external sidechain inputs, I couldn’t make the kick drum’s bottom-octave spectra key the limiter’s high-frequency band (at roughly 4 kHz) to exclusively rein in the kick’s excessively clicky beater hits; instead, limiting high frequencies also unavoidably attenuated snare drum strikes, which didn’t need any treatment on this particular cut. I also wished the ML8000 had a mid-side mode to allow discrete dynamics processing in each channel. For example, limiting excess midrange energy in center-panned elements of a mix also attenuated the same spectra in the mix’s side channel.

I got great results using the ML8000’s multiband limiter section in Crush mode on room mics for drums. Dialing in the softest knee and fastest release time delivered an explosive sound, and I could tailor how much the kick and snare each got limited (see the Try This sidebar).

I also got terrific results using the ML8000 on electric bass guitar. I used the multiband stage to pump up the gain in the lower bass band, and then limited the band using a fairly hard knee in Soft mode. Using a very soft knee for the master limiter (also set to Soft mode) and about 2 to 4 dB of gain reduction added subtle distortion that made the bass growl while sitting it perfectly in the mix. Awesome!

My only disappointment with the way the ML8000’s GUI functioned was, there was no way to clear all meter “overs” at once (say, by double-clicking one clip LED); McDSP says it plans to implement this capability in the future.

The ML8000 gets very high marks for its excellent sound quality, separate multiband and limiting stages, wide variety of limiting algorithms and intuitive GUI. The plug-in sounds terrific on individual tracks and does a great job handling basic mastering applications. There are more flexible and fully equipped limiters for executing advanced mastering techniques, but what the ML8000 does, it does great.

PRODUCT SUMMARY

COMPANY: McDSP
PRODUCT: ML8000 Advanced Limiter
WEBSITE: McDSP.com
PRICES: Native: $199 ($179 MAP); HD: $299 ($279 MAP)
PROS: Sounds great. Separate multiband and wideband limiting stages. Includes a variety of limiting modes. Bands can be linked, with offsets preserved. Intuitive GUI.
CONS: No freely programmable internal sidechain filters or external sidechain inputs. No M/S mode. Can’t clear all clip LEDs at once.

TRY THIS

For a bombastic sound on room mics for drums, first click the ML8000’s Snap button to move the multiband Threshold controls to their bands’ respective input levels. Set the limiter to Crush mode and the softest knee and quickest release time possible. After linking all the bass bands, you can discretely control how explosive the kick drum will sound by adjusting the input-gain and threshold controls for the link master.

Michael Cooper is a recording, mix, mastering and post-production engineer and a contributing editor for Mix magazine.

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