DrawmerUSA - MX Series Application Guides

DRAWMER MX30 2-Channel Gate/Compressor/Limiter - $479 MSRP
The MX30 is a wonderful little box that has all the basic dynamics signal processing functions needed for a high quality project studio or sound reinforcement application. It might look simple, but it's based on proven Drawmer circuitry used in the Pro series. While it has a limited number of controls and tweak parameters, it sounds great and it's quick and easy to set up and use.

Studio Applications:
As a studio compressor, the program dependent attack and release times and "soft knee" onset of gain reduction provide smooth gain reduction whether you're compressing individual channels or, in the linked mode, a full stereo mix or stereo source.

Compression controls are Threshold and Compression Ratio. For most applications, a ratio of 2.5:1 to 5:1 will be appropriate. Use lower ratios for well controlled sources that just need a little evening-out, and higher ratios for those vocalists that need taming. Set the Threshold control so that you don't lose any of the quieter parts in the mix, and adjust the Output Level to make up for the compressor's gain reduction, bringing the track back to the proper mix level.

The Gate is a "soft" gate with a fast/slow release switch. The attack time is fixed, and is suitable for material with a slower attack envelope such as a vocal. Set the gate Threshold to the point where the quietest parts of the track get through, but headphone leakage, paper rustling, and breaths between verses don't.

The Limiter is a "brick wall" level control which does not allow any overshoot. Attack time is essentially zero, so it will not allow even the shortest transient to go above the limiting level. It's great for taming the occasional wild peak that's driving your digital recorder to full scale distortion once every few measures. By limiting the peak level, you can raise the average level of the track, improving signal-to-noise ratio and increasing digital resolution.

A Stereo Link function allows both channels to respond in the same manner to dynamic signals which come in on either channel. Generally when used as a "bus" or "program" compressor, you'll want to engage this mode so that a loud signal on one channel doesn't reduce the gain on that channel only and, cause the entire stereo image to shift.

Inputs and outputs are available both unbalanced at -10 dBV level on ¼" jacks and balanced at +4 dBu level on XLR-type connectors. Both outputs are active, so it's possible to use them simultaneously. For example you might use the unbalanced output as a console insert return for a stereo mix while using the balanced output to feed a direct compressed output to a recorder.

Live Sound:
In live sound applications, you often don't have time to tweak settings as you do in the studio. By the time you find the right settings for threshold, attack and release times, compression ratio, and output level, Bang! The song's over and you need another group of settings for the next song. The simple controls and near automatic operation of the MX30 allow you to quickly tame program dynamics and get on with your mixing chores. A touch of compression on the vocal channels is often all that's required to keep things within range of your normal mix settings.

The program adaptive gate is ideal for keeping the monitor sound out of the vocal mics when the singers aren't singing, or for quieting noisy stomp boxes when a guitar or bass isn't being played.

When the MX30 is used on the full mix, the peak limiter is ideal for protecting amplifiers and drivers as well as keeping the volume level safe from the music police who will ask you to turn it down. Set the maximum output level and not even the loudest peaks will exceed that.

If you're mixing in stereo, the Stereo Link switch will keep the center of the stereo image from shifting as dynamics change from channel to channel.

Inputs and outputs are available both unbalanced at -10 dBV level on ¼" jacks and balanced at +4 dBu level on XLR-type connectors. Both outputs are active, so it's possible to use them simultaneously. For example, in an instrument rack rig, you might use the unbalanced output to feed the instrument amplifier on stage while sending the balanced output back to the house console.

Installed Sound Applications:
Installed sound systems are more often than not operated in a set-and-forget mode. The installer wires up the equipment, sets it for typical operation, and it stays that way for years. Typical applications for the MX30 are in paging systems and sound reinforcement for single purpose applications with different sources such as a speaker's podium or corporate meeting room.

Set the gate threshold so that ambient noise such as air conditioning or people speaking in normal conversational level away from the microphone is gated off. The sound system will remain silent until someone steps up to the microphone to speak.

With a wide variety of speaking voices and often nobody attending to level setting, the compressor can help to even out the differences between loud and quiet speaking voices and those who swallow the mic and others who shy away from it. A compression ratio setting in the range of 3:1 to 6:1 with a fairly low threshold will go a long way to keeping everyone audible.

The peak limiter is a good safety valve. Should something go awry the system will be protected from overload.

Inputs and outputs are available both unbalanced at -10 dBV level on ¼" jacks and balanced at +4 dBu level on XLR-type connectors for easy integration into any system.

DRAWMER MX40
Four Channel Frequency Dependent Peak Punch™ Gate - MSRP $649

The MX40 is a single rack space unit consisting of four independent gates with a couple of twists. A gate allows signals above a certain threshold level to pass through but attenuates signals below threshold so they don't appear at the output. On the MX40, the gated level is switchable between -90 dB and -20 dB so that the output doesn't go completely "dead" when the input drops below threshold, but rather retains some lower level ambient sound. This yields a more natural sound in some applications.

An adjustable bandpass filter can be inserted into the threshold detector path so that, regardless of level, only signals within a certain frequency range will open the gate. This is often preferable to full band gating, and with careful adjustment, you can use the tunable filter to allow the gate to open, for example, on the floor tom, but stay closed on the snare. Similarly, you could adjust another channel to open when the snare it hit, but reject the toms. This goes a long way to improving definition in your mixes. A "key listen" switch allows you to hear the output of the key filter rather than the gated output, making it easy to tune the filter to the desired range.

The Peak Punch™ feature is unique to Drawmer. When engaged, the initial attack when the gate opens is expanded upward momentarily adding punch to the attack of the gated signal. It really works on percussive sounds, improving definition without raising the average signal level to the point where it would be squashed by a following compressor.

The unique Drawmer "traffic light" display clearly shows when gate input signals are above, below, or at threshold for quick setting of threshold controls. The MX40 employs the same "trigger stabilization" as the more advanced DS201 and DS401 gates to prevent chatter and false triggering when the input signal is very close to threshold.

Gate inputs and outputs are balanced, +4 dBu operating level on XLR-type connectors. The external key inputs are ¼" unbalanced jacks.

Studio Applications:
The most common studio application for the MX40 is to help separate percussive instruments (most often the drum kit) where multiple microphones are placed on the individual drums. By gating the individual mic signals, you can reduce or eliminate the muddy sound or comb filtering that occurs when mixing nearly the same signal picked up by two mics intended for separate drums.

By carefully setting the frequency control and threshold, you can keep each microphone gated off except when its source is playing. By allowing only the octave in the 50 Hz range to trigger the gate, only the kick drum will get through. By setting the frequency control on the floor tom channel in the 100 Hz range, you'll keep the kick out of the floor tom channel. By engaging the Key Listen switch, instead of hearing the full bandwidth out of the gate, you'll hear only what's getting through the filter. By playing an individual drum and sweeping the filter frequency, you can quickly find the frequency that's most characteristic of the source.

Of course for broadband gating applications, the key filter can be switched out with the press of a button. Once you get the frequency and threshold settings adjusted for best separation, press the Peak Punch™ switch and listen to the transients come alive.

Normally a gate is triggered by its input signal, but on occasion you may wish to trigger it to something different. The MX40 provides a jack on the rear panel for an external keying source. One common application for this is to tighten up a bass track by keying it from the kick drum. With nothing plugged into the External Key jack, engaging the Ext Key switch on a gate channel causes that channel to be keyed along with Channel 1. You can tighten up a horn section by putting the player with the best timing on Channel 1 and using him to gate the players going through the other channels. For stereo sources, adjacent channel pairs can be linked so that their gated outputs will close and open simultaneously.

Live Sound Applications:
Concert riders often require multiple gates, and the MX40 is a cost effective and great sounding way to accommodate. The most common live sound application for gating is to help separate instruments in the multiple-miced drum kit. By gating the individual mic signals, you can reduce or eliminate the muddy sound or comb filtering that occurs when mixing nearly the same signal picked up by two mics intended for separate drums.

Once you get the frequency and threshold settings adjusted for best separation, press the Peak Punch™ switch and listen to the transients come alive.

Of course for broadband gating applications, the key filter can be switched out with the press of a button. You might find this appropriate when gating background vocals.

Installed Sound Applications:
A common installed sound application for a multi-gate is to gate several microphones around a conference table, or to gate the podium microphone off when an A/V presentation starts.

In this application, frequency selective gating is usually not appropriate, so the key filter would be switched off. To avoid the jarring "total silence" when someone stops speaking, the Range should be set so that the channel gain drops by 20 dB rather than full 90 dB gating.

DRAWMER MX50 Two Channel De-Esser
Sibilance, the hissy or spitty "S" and hard "T" and "C" sounds, is a natural element of the speech formation process. It often becomes exaggerated in today's recordings as a result of close microphone positioning, extended high frequency response, and recording of less experienced singers or talkers. A de-esser works by dynamically reducing its gain, but unlike a general purpose compressor, the signal going to the compressor's level detector passes through a tunable bandpass filter. Gain reduction takes place only when signals within a certain frequency range exceed the threshold.

The concept is fairly simple, but there are pitfalls. Every compressor has a threshold at which gain reduction starts. Since the signal level going into the de-esser may vary over a fairly wide dynamic range, setting a fixed threshold for the onset of de-essing is often not completely satisfactory. Because sibilance is a function of the human vocal chain, it's just as noticeable during quiet passages as loud passages. The loud passages will be de-essed, but the low level passages hiss right on through unaffected because the sibilance level never hits the threshold.

The MX50 solves this problem by employing a floating threshold so that the de-essing is accomplished relative to the average input signal level rather than to fixed threshold. In addition to increasing its effectiveness over the full dynamic range of the source, this reduces the general dulling of the high frequencies which is common in other de-essers. Some apparent high frequency loss is inevitable, however, so the MX50 includes an "Air" switch which inserts a high frequency shelving boost to restore the highs.

Most de-essers reduce the level of the entire signal when the level in the sibilance frequency band reaches the threshold. The MX50 provides an alternate mode of operation in which only frequencies above the de-ess frequency setting are reduced when de-essing takes place. This allows the MX50 to be particularly efective on full program material in addition to working on just a vocal channel.

Inputs and outputs are balanced, +4 dBu operating level on XLR-type connectors.

Studio Applications:
Using the MX50 in the studio is simple and straightforward. Most frequently you'll patch it into a console channel insert when mixing or between the mic preamp and recorder when tracking. Should you also want to compress the track, you'll probably find that compressing the de-essed signal is more effective than de-essing a compressed signal (since compression can tend to exaggerate sibilance), so try that signal chain routing first.

Most of the time you'll find the split band mode to be most effective with minimal side effects.

The De-Ess control adjusts the amount of gain reduction which will take place on the loudest sibilant peaks. The Frequency control tunes the compressor side chain filter to the predominant problem frequency. While sibilance is usually found in the 2.5 to 6 kHz range, for a given voice, it's usually limited to a fairly narrow frequency band within that range, so it's fairly easy to zero in on the frequency setting by listening.

Set the De-Ess control for about 10 dB of reduction, and tune the Frequency until you hear it working. You're there. Now, re-adjust the De-Ess control so that the sibilance isn't objectionable.

Listen with and without the Air switch and decide if the high frequency boost is appropriate for the voice and the mix. The Bypass switch will allow you to compare the sound with and without de-essing.

If you're de-essing a full stereo mix rather than individual channels, the Link switch averages the level of the two channels to determine the floating threshold level. It's still necessary to adjust both channels independently since there may be a difference in sibilance characteristics between them depending on the program material.

Live Sound Applications:
Using the MX50 in a live sound application is simple and straightforward. Most frequently you'll patch it into a mixing console channel insert.

Most of the time you'll find the split band mode to be most effective with minimal side effects. The full band mode may be more effective however, if there's a lot of leakage into the vocal mic from monitors or live instruments on stage. Start with the split mode and listen to what happens when you switch to the full band mode.

Set the De-Ess control for about 10 dB of reduction, and tune the Frequency until you hear it working. You're there. Now, re-adjust the De-Ess control so that the sibilance is reduced to a workable amount. Bear in mind that concert audiences often expect to hear some sibilance, and a bit is often helpful to allow a vocal to cut through a mix, so don't go too far.

Installed Sound Applications:
Since the sibilant characteristics of a voice are highly individual, a de-esser isn't commonly found in an unattended sound system installation. However, if some sibilance protection is desired, the MX50 is ideal because its floating threshold can accommodate a wide range of speaking voices.

The MX50 should be connected between the output of the mixer and input of the power amplifier, ahead of an overall limiter or compressor if one is installed.

The following settings should give some protection when the MX50 is used in a set-and-forget environment:
Frequency: 3.5 - 4 kHz
De-Ess: -10 dB
Band: Split
Air:

Off If the installation is stereo, set the Link switch On and set the controls on both channels as above .

DRAWMER MX60 Single Channel Front End ONE - MSRP $725
The MX60 is a complete signal processing front end in a single rack space. Borrowing circuitry from some of the most successful Drawmer models, the MX60 provides all the tools you'll need to go from a mic, a line level source, or a musical instrument pickup all the way to recorder or power amplifier. Functions includ a mic, line and instrument preamp, gate, de-esser, compressor, equalizer, and peak limiter, plus a unique circuit which convincingly emulates tube saturation. It's an ideal signal chain for the project studio recording directly to hard disk through a computer audio interface, and it's also a flexible and full featured single channel for live or installed sound use.

Studio Applications:
Since the MX60 provides all the functions you'll need in a signal chain, it should be connected so that there's as little as possible between its output and your recorder. Ideally you'll connect it directly to a sound card or recorder line level input. The MX60's -10 dBV unbalanced and +4 dBu balanced output levels should accommodate whatever you have. Connect your input source to the appropriate input section and go.

The input section accommodates a wide range of microphones, providing switchable 48V phantom power and up to 60 dB of gain. A 100 Hz high pass filter can be switched in to compensate for a mic's proximity effect or to reduce low frequency rumble due to traffic or air handler noise.

A switch selects between the rear panel mic and line inputs. When Line is selected, the gain control provides up to 30 dB of gain and 30 dB of attenuation. The line input is useful during mixdown, allowing you to use the dynamics, equalizer, and tube saturation simulator to process a recorded track.

The Ø Rev switch inverts the polarity of the selected input source.

The dynamics section follows, with a program-adaptive gate immediately following the input section. The gate circuitry is borrowed from the MX30 and its operation is similar. A single control sets the level at which the gate opens, and a single switch selects fast or slow gate release.

A de-esser follows the gate and precedes the compressor, with a single control to select the amount of gain reduction at high frequencies, and a single switch to select the predominant sibilance range of a male or female voice. A compressor with program-dependent attack and release times follows the de-esser. The compressor is similar to that in the MX30, and operates in a similar manner. Threshold, compression ratio, and make-up gain controls are provided.

The MX60 three band equalizer consists of low and high frequency shelving filters plus a fully parametric peak/cut section adjustable over the range of 150 Hz to 10 kHz. Some care is required in setting the fully parametric section since bandwidth, frequency and gain are all adjustable. A convenient way to zero in on the proper settings is to apply maximum boost with the bandwidth set at 0.5 octave. You'll quickly hear where the problem frequency is located. After setting the frequency, adjust the bandwidth and amount of boost or cut to get the desired effect. In general, narrow bandwidths are useful for cutting offending frequencies, and wide bandwidths are useful for emphasizing musical frequency ranges.

The Tubesound™ section is a purely creative tool, so how you use it is up to you. The three controls add distortion in three different frequency bands.

The Output section consists of a level control preceded by a fixed threshold (+16 dBu) peak limiter. When the MX60 is used with a digital recorder, the limiter can be used to prevent overload on signal peaks. To do this, put in a steady tone and adjust the input level so that the limiter LEDs are on. Then adjust the Output Level control so that the digital recorder's meter indicates just short of full scale. By adjusting the Input Level so that the Clip light on the MX60's input meter almost never lights on normal program material, the limiter will only act when you're in danger of overloading the recorder.

Live Sound Applications:
Since the MX60 provides all the functions you'll need in a signal chain, it can fully replace a mixer channel and a rack of signal processors. In a live sound application, it can be a premium channel path for the lead singer or actor on stage. If you're a performer who normally works with different sound systems, you can carry it along and be sure to have your sound wherever you go. Running a karaoke system? Use the MX60 for the singer's channel and you'll have the power of a rack full of studio equipment in a single rack space.

Typically, the MX60's output is connected to a mixer channel line input, insert return, or auxiliary return, minimizing the signal path between it and the main mixer output.

The MX60's -10 dBV unbalanced and +4 dBu balanced output levels should accommodate connection to any mixer, power amplifier, or even powered speakers.

A front panel Instrument jack turns the MX60 into a direct box (DI), providing a 1 megohm input for an instrument pickup. When using the Instrument input, a switch provides a 20 dB gain boost, and a Bright switch adds a high frequency boost similar to the response of an instrument amplifier. Since both the -10 dBV and +4 dBu outputs are active simultaneously, you can use the MX60 as the front end to an instrument amplification rig. Connect the ¼" output jack to the input of your on-stage amplifier and send the XLR output to the house mixing console.

The Ø Rev switch inverts the polarity of the selected input source.

The Tubesound™ section is a purely creative tool, so how you use it is up to you. The three controls add distortion in three different frequency bands.

The Output section consists of a level control preceded by a fixed threshold (+16 dBu) peak limiter to protect speakers or power amplifiers further along in the chain.

Installed Sound Applications:
In a single channel installed sound system, for example to amplify a single podium microphone, connecting an MX60 between the microphone and power amplifier or powered speaker gives complete control over the sound. It can also be used as a "super mixer channel" in conjunction with a mixer in a larger system by connecting its output to a mixer channel line input and set the mixer for unity gain with the equalizer section bypassed or set flat. Output levels of -10 dBV and +4 dBu will match up to any mixer or power amplifier.

The de-esser and compressor are easy to operate and will tame the voice of an inexperienced speaker or singer. The high and low bands of the three band equalizer are useful for compensating for boomy or excessively bright room acoustics, while the fully parametric mid-band is handy for reducing feedback while the Tube Sound™ processor can be used to warm up a voice. The peak limiter will keep things from getting too loud and perhaps causing damage to equipment further upstream. In a single channel system, the master output level control serves as the system volume control .