The TwinTrak Pro is the newest member of Focusrite's Platinum Range family of signal processors. A 2U mic pre that's designed for dual mono or stereo tracking, the TwinTrak Pro features a “mid-scoop” EQ section and compressor on each channel. The compressors can be linked in stereo, and the unit can provide digital output with Focusrite's optional A/D converter card.
The front plate of the TwinTrak Pro bears a resemblance to its Platinum Series siblings. The unit's brushed-aluminum finish, black lettering, pear-shaped switches, conical black-rubber knobs, and cobalt blue meters are characteristic of the Platinum line (see Fig. 1).
The TwinTrak Pro shares another Platinum trait: XLR inputs on the front panel. That's a clear indication that the unit is designed for home and project studios, where it may reside on a desktop. I'm not a big fan of units with front-panel inputs, because they are more difficult to install and connect in studios like mine, in which mic lines are snaked from a separate room and wired to patch bays.
Each channel on the TwinTrak Pro front panel offers a +48V switch; an Air switch, which inserts an inductor into the preamp circuit to enhance the high-frequency response; and an Impedance control that is continuously variable from 60ž to 3.3 kž. A ¼-inch instrument input and a High Gain switch, which boosts the input level by 20 dB, are next to the XLR connector. The input defaults to mic level, and separate Inst and Line switches select alternate inputs. Red LEDs indicate which one is active.
The Level control serves as a mic gain, instrument gain, or line trim, depending on which input you are using. Mic preamp gain ranges from 0 to 60 dB, and the instrument gain ranges either from 0 to 20 dB or from 20 dB to 40 dB, depending on whether the High Gain switch is depressed. The line trim ranges from -10 dB to +10 dB. The preamp section also includes a Polarity Reversal switch and a High Pass Filter switch, which rolls off any frequencies below 75 Hz with a steep slope of 18 dB per octave. A 6-segment vertical LED meter displays the output level in dBfs (-42 to 0), clearly signaling that the TwinTrak Pro is appropriate as a front end for digital systems. To achieve a +4 dBu output when recording onto analog media, the clearly written and instructive manual puts the ideal level at about -18 dBfs.
THE SCOOP ON EQ
The Mid Scoop EQ section contains an In switch for engaging the circuit and a Deep switch for increasing the cut from -6 dB to -12 dB. A Cut Frequency control determines the center frequency of the scoop, which is variable from 120 Hz to 2 kHz. The Q, or slope, of the bell is set at 1.5 for the -6 dB cut and a steeper 3 for the -12 dB (Deep) cut.
The Optical Compressor section houses switches marked In, Slow Attack, Hard Ratio, and Hard Knee. The In switch engages the compressor. Slow Attack changes the attack time from .5 ms to 5 ms. Hard Ratio changes the ratio from 2.5:1 to 6:1. Hard Knee gives a more aggressive, more apparent attack.
The first rotary control in this section is marked Compression. I initially thought that this was a way of skirting traditional compressor controls, but according to the manual this is just an inverted Threshold knob. The settings range from -12 dB to -42 dB as you turn the knob clockwise.
The Release knob lets you adjust the release time from 100 ms to 1 second. When the knob is fully clockwise, the release goes into Auto mode. According to the manual, this mode “creates a release time dependent upon the average level of the incoming signal,” a helpful option for users who don't fully understand how to use compression. The final knob in the compressor circuit is for Makeup Gain, which lets the user boost the compressed signal by up to 21 dB. A Stereo Link switch makes Channel 1 the master for applying compression settings equally to both channels.
In the Digital section, LEDs indicate external sync lock as well as signal present at the rear-panel digital input section. Below the LEDs is a switch for activating the Digital Insert, which converts and reroutes the signal present at the S/PDIF input to the preamp instead of to the monitoring section. This feature lets you route a digital signal through the EQ and compression circuits, as long as nothing is plugged into the line input jack on the rear panel. If you plan on switching the TwinTrak Pro back and forth between digital and analog line inputs, install the unit in a rack that allows convenient access to the rear panel.
With the Digital Insert switch up, the S/PDIF signal is directed to the Latency Free Monitoring section. (No plugs can be in the Monitor Input jacks.) In this section the TwinTrak Pro is quite flexible for use with DAWs. The Input Balance control adjusts the relative levels of the discreet channels. When the Mono switch is engaged, the adjusted levels are sent equally to both outputs. The FX Level control determines the amount of external stereo effect added to the monitor mix. (If you want to record with an effect you must use the insert in the preamp section.) The Headphones Mix pot controls the balance between the TwinTrak Pro input signals and audio playback from a DAW (you must mute the track onto which you're recording to avoid feedback).
To the right of these knobs are level controls for the separate monitor and headphone mixes. You can listen to the headphone mix through your speakers by pressing the Headphones to Monitor switch. Without this switch depressed, the monitor outputs reflect only the monitor or S/PDIF inputs. (Most often, you'll want these two mixes to be the same anyway. If you could adjust the level of the input channels independently in each mix, then I could understand the need for two buses; as it is, however, having two mixes seems superfluous.) Also included in this section are the headphone jack and a Monitor Mute switch, which is handy for quickly controlling feedback. Muting doesn't affect the headphone mix.
The front panel also contains the power switch and the meters for checking levels at both the analog outputs and at the input to the optional A/D card. Nestled in the meters are red overload lights that shine when the signal exceeds 0 dBfs (or +22.4 dBu).
I have one small complaint about the controls on the front panel: some of the switches light up when depressed, and others don't. For example, the low-cut switch lights up, but the polarity switch doesn't. I wish that they all would light up when depressed to help me see their position at a glance.
The back of the unit boasts +4 dBu balanced TRS line input and XLR output jacks, unbalanced TRS (tip=send) inserts and Compressor Side-Chain inputs, and +4 dBu/-10 dBV unbalanced TS outputs for each of the two channels (see Fig. 2). Two balanced ¼-inch TRS jacks each are provided for stereo FX Send and stereo FX Return. The monitoring section contains a pair of TRS jacks for the monitor inputs, another pair for the headphone mix output (not affected by the Headphone Level control), and a pair of XLR jacks for the monitor outputs, all carrying +4 dBu balanced signals.
The built-in DAC Input section contains an RCA jack for S/PDIF in, and a BNC connector labeled only Word Clock. You might think that because it is in the DAC Input section, it is a word-clock input jack, but it is for word-clock output. That makes sense, because the S/PDIF coming from another digital interface would contain clocking information, and without the optional ADC card a word-clock output would be the only way the TwinTrak Pro could be a master to other digital devices. It would have been nice, however, if Focusrite had labeled it as such. As for the optional ADC card, it contains an RCA output jack for transmitting a S/PDIF signal as well as a Word Clock Input (labeled, this time), and two switches: one for choosing between sampling rates of 44.1 kHz and 48 kHz, and another for doubling the chosen rate to either 88.2 kHz or 96 kHz, respectively. The card's resolution is always 24-bit with no dithering, so if you are feeding a 16-bit input the extra 8 bits will be lopped off.
TwinTrak Pro Specifications
Channels2Analog Input(2) balanced XLR; (2) balanced 1¼4" TRS (line);
(2) ¼" TS (instrument); (2) ¼" TRS (monitor inputs)Analog Output(2) XLR (main); (2) XLR (monitor);
(2) unbalanced ¼"Additional Analog Ports(2) ¼" unbalanced TRS inserts;
(2) ¼" unbalanced TRS compressor sidechain inserts; (4) balanced ¼" TRS effects sends/returns; (2) ¼" TRS headphoneInput Impedance60ž-3.3 kž sweepable (mic); 10 kž (line/insertreturn); >1 Mž (inst)Frequency Response10 Hz-200 kHzGain0-60 dB (mic); -10 dB to +10 dB (line); 0 dB-+40 dB (inst)Total Harmonic Distortion0.005% (mic input at maximum level);
0.0006% (line); 0.006% (inst.)Dimensions2U × 7" (D)Weight11 lb.
Focusrite included the optional A/D card with the review unit. It worked and sounded great at all four sampling frequencies.
ON THE TRACKS
I used the TwinTrak Pro in my studio for a couple of months and was able to test it with a large variety of microphones, instruments, and sound sources. I also ran direct comparison tests against other preamps and compressors.
I noticed several positive elements early on. The variable impedance potentiometer provides a wide spectrum of tonal control. The TwinTrak Pro's manual gives a thorough explanation of the effects that input impedances have on microphone characteristics. In general I found that the range above 1.6 kž is a good one for most mics. Anything below about 500ž (the setting goes all the way down to 60ž) was unusable (except as a special effect), with a complete loss of high end.
The Air switch inserts an inductor into the preamp path that, according to Focusrite, “closely emulates the characteristics of more costly transformer-based mic pres.” Basically, the inductor circuit boosts the high end (the frequencies affected depend on the type of mic used), which I found helpful in a few instances, particularly with distorted lead guitar. It opened up the high harmonics nicely and helped the guitar sit in the mix at a lower level yet be heard clearly. For the most part I opted to keep this switch out, which gave most signals a slightly more natural sound.
The Mid Scoop EQ section never came in handy for me. I could imagine that if you were using cheap mics in a bad-sounding room, perhaps this feature could clean some of the mud out of your signal. I'm not a proponent, however, of using drastic EQ such as this-6 dB even without Deep engaged — in the signal path when recording. This feature might give good results, however, when accessing the unit during mixdown.
Using the S/PDIF input, the D/A converter sounded much smoother and more natural than the converters of my Digidesign Digi 001. Less honk in the horns and more shimmer in the cymbals were two noticeable effects of the TwinTrak's converters. If you feed the monitor section from a DAW, your mixes may sound clearer than your regular audio interface, although you will need an external mixer for volume control. I also noticed that the TwinTrak Pro runs hot due to the converters.
COMPARE AND COMPRESS
For preamp comparison tests, I connected a Fender Precision bass to a small Gallien-Krueger combo amp and miked it with a Blue Bluebird microphone, which is bundled with a variety of Focusrite products (see the sidebar “A Bluebird in a Bundle”). I compared the TwinTrak Pro with other Focusrite preamps — an ISA 428 Pre Pack (see the review in the March 2004 issue of EM), a Green 1 Dual Mic Pre, and an original issue Platinum VoiceMaster. I found that the TwinTrak Pro sounded much better than the VoiceMaster; it should, because Focusrite redesigned the preamp circuit, giving it far more midrange punch and a more solid low end. Compared with the Green 1, the TwinTrak Pro was a bit smoother and a little less brittle, though these were the two preamps that sounded most similar. Not surprisingly, the ISA 428 sounded the best — crisp yet smooth in the high-mids and thunderous in the low end compared with the TwinTrak Pro.
Plugging the bass directly into the ISA 428 and TwinTrak Pro (the VM and Green don't have instrument jacks) yielded surprisingly similar results. I was very pleased with the direct bass sound in both cases.
The next test was with distorted guitar. I ran a Fender Jaguar through a Bedrock tube head and 4 × 12 cabinet miked with a Shure SM57. All four preamps sounded comparable for this application, although both Platinum boxes broke up a little more on chunky low chords than the Green 1 or ISA 428. With a cleaner sound on the amp, the TwinTrak Pro sounded smoother and brighter than either the Green 1 or the VoiceMaster, but not as clear as the ISA 428. This was one case in which the Air switch was better left alone — engaging it made the guitar sound too thin.
The TwinTrak Pro preamp sounded better than the original VoiceMaster and the Green 1 Dual Mic Pre, but not quite as good as the ISA 428. Given the TwinTrak Pro's cost, that's not surprising.
I compared the TwinTrak Pro's compressor with two budget stereo compressors: the FMR Audio Really Nice Compressor (or RNC), and a dbx 266A. The TwinTrak Pro's compressor was smoother and more useful than the dbx unit, and similar in sound to the RNC's SuperNice mode.
The RNC is more versatile than the TwinTrak Pro's compressor section. For stereo bus compression on a full jazz sextet mix, however, I dialed up similar settings on both units, getting as close as possible given the lack of fine-tuning of ratio and attack on the TwinTrak Pro. The TwinTrak Pro yielded cleaner and crisper cymbals and punchier bass than the RNC, which is a highly regarded, low-cost compressor. I was so impressed that the TwinTrak Pro has become my preferred compressor for stereo material and second choice (after a Universal Audio 1176) for mono signals.
LEAVE IT TO THE PRO
The TwinTrak Pro surprised and pleased me with its quality and versatility. If you're looking for two channels of affordable pre amplification, EQ, and compression, with optional A/D conversion, take a listen to the TwinTrak Pro.
Eli Crewsis an Oakland-based engineer and musician. You can contact him atwww.newimprovedrecording.com.
stereo voice processor
ADC card $250
TwinTrak ProPak (with Blue Bluebird microphone) $1,635
FEATURES4.0EASE OF USE3.5QUALITY OF SOUNDS3.5VALUE4.0RATING PRODUCTS FROM 1 TO 5
PROS: Comprehensive metering at various stages of processing. Continuously variable impedance control for mic input. Compressor sounds clean and transparent. Flexible monitoring system for use with DAWs. Strong headphone amplifier.
CONS: Mic input jacks on front of unit. Analog connectors must be physically disconnected in order to route digital signal to line inputs and monitor inputs. Unit runs hot due to converters. Word-clock output not labeled.