The Falcon Compressor/Limiter and Syren Microphone Pre-Amp are single slot Crane Song 500 tube-based modules. Both use a single 12AX7 running in class-A that's vertically mounted in a ceramic socket with cooling vents cut in the top of the modules' cases. The tubes are carefully selected and tested for lowest noise and all units used mu-metal shielded LL1585 Lundahl output transformers.

For these modules, Dave Hill designed a voltage converter on an internal 'daughter board' to derive both the tube's 5-volt filament voltage and 185-VDC plate supply. Carefully tuned input and output EMI filters are used to prevent the power supply's 600 kHz switching noise from polluting the audio, the 500 rack's +/- 16-volt power supply rails and other modules in the same rack.

The Falcon uses a variable impedance circuit to change gain in a feedback-styled compressor design. The compression ratio varies depending on the amount of gain reduction--mimicking the characteristics and operation of an opto-compressor. The Comp/Limit front panel switch selects between soft knee and hard knee compressor curves. This gain control element is followed by a tube make up amp with output Gain control.

Falcon is a colorful all-analog compressor with two operational modes controlled by the front panel's 100/Color switch. The flattest and cleanest mode is 100 with no negative feedback; the Color mode uses negative feedback for a more euphonic and creamy tonality.

A great idea on a hardware compressor, I liked the Wet/Dry control knob for immediate parallel processing. With no need to do external patching, there are no phase/polarity issues possible.

Attack and release times are set using a pair of three-position toggle switches each simply labeled Attack and Release with the top position the fastest. Both attack and release times are specified for a 12 dB gain change, and I found all three choices to be effective with the middle or medium positions as good starting points.

Attack times are: 100 microseconds, 7ms, and 20ms. Release times are specified in a range and are program dependent. Fast is from 75 to 200ms, medium 300ms to 1 second, and slow is 1.4 to 3.5 seconds. To avoid distorting low frequencies using fast release times, deep gain reduction recovery is in two-steps with a short, momentary hold period just before returning to unity.

At the bottom of the Falcon front panel is a three-position toggle switch with Bypass, In Circuit, and Link positions. In the Bypass position (down), a nitrogen-filled NEC relay back on the unit's edge connector is triggered for true hardwire bypass. The middle switch position puts the compressor in circuit and in the up position, link mode.

Any Falcon compressor can be configured to serve as master or slave with up to six Falcons linkable for surround mixing. The attack, release, output/GR meter switch, color, threshold knobs and switches on the designated master will simultaneously control those controls and switches on all slaved Falcon compressors. All compressors linked will track to within 0.1 dB of each other.

Crane Song supplies special multi-pin ribbon cables for linking. Falcon compressors are slotted next to each other in the rack and a ribbon cable would daisy chain the link path(s) between Falcons via an open slot in the top of the modules.

Free Bird Falcon!

I tried the Falcon on just about every source and, since there is no separate input level control, I found hot source levels give you the largest operating threshold range for invisible to extreme compression processing.

As a bass guitar compressor, I found the 100-position cleaner with the middle attack and release times perfect. The fastest release time setting will work with minimal distortion for loudness enhancement using Comp mode and about 2 to 6dB of compression.

Kick drums take on solid consistency using the Falcon. Here the Wet/Dry control worked well to blend the kick track pre-compressor with Falcon set to flatten the sound. I used Comp and Color, slow attack and fast release positions. The Wet/Dry was at about 50/50 for recovering some of the subsonic, ambience and sustain from the original kick drum.

Switching from Comp to Limit necessitates a new threshold setting and output gain adjustment. So on a bass synth track I was able to selectively dirty up the sound by selecting various attack and release times.

I placed the Falcon on an insert in Pro Tools and used medium attack and release times for about 7 to 10dB of compression. I used Limit and 100 modes, full Wet and produced a steady "blown up" sound in the Falcon's output stage so I switched to reading GR as the little LED-lit VU was pinning!

My favorite use for Falcon was for a young female singer. I used slow attack, fast release, Comp mode and Color position to keep the voice clear, bright and present with about 2 to 5dB of compression maximum. Vocal compression is where the differences between 100 and Color modes are most hearable. The Wet/Dry control comes in handy for heavy compression (6dB or more indicated) to add back in a bit of the original--it's cheating--but I got away with a clear vocal sound that laid right in the track nicely.

Great 500 Tool

Syren is a single channel microphone pre-amp with dual gain stages and the ability to overdrive each stage separately for a wide range of pre-amp sounds. It's capable of super clean to colorful to over-the-top tube saturation.

Syren has a complete set of controls nicely laid out on its front panel. There are: a 1/4-inch 1.2-megohm Hi-Z input jack, Mic/DI switch, a 24 dB/octave 90Hz high-pass filter, polarity reversal, +48-volt phantom on/off, and the output amp's Open/Color switch. Like the Falcon, Syren's output amp will operate with either no feedback (Open) or negative feedback (Color).

There is a three-position attenuator switch with 0, -15, and -25 dB positions placed in circuit before a mu-metal shielded LL1576 Lundahl microphone input transformer that then drives the 12AX7's 1st triode stage.

The front panel's top input OD LED lights at -6dB for the output of this first stage--although it is not necessarily distorting. To not have this, you would either lower the source's incoming level and/or use the attenuator.

Syren's Input Gain control sets the output level of this first stage to drive the second triode stage output line driver. The front panel's lower OD LED is placed after this stage and the Open/Color and HPF sections, but before the Output control and output transformer. Although a little small, the OD LEDs work well to quickly set up initial gain staging. You can "blow up" the first stage with excessive input levels and/or also overdrive the output line driver with maximum Input Gain control settings.

In The Studio

For recording clean vocals, I ran the Output control knob full up and ran the Input control in the range of 10 to 2'oclock depending on the microphone type and how loud and close my singer was. Modern microphones like a Brauner Phanthera put out plenty of level so I would have to turn the Input even lower. Close condensers placed on snare drums sounded awesome through the Syren.

For vocals I always used Syren's Open mode for a fat, rich sound and good low frequencies. Syren is a sonic guilty pleasure with creamy and rich overload characteristic that can fill out the sound in a kind of densely packed way. On my singer's loudest moments, the second LED just flickered occasionally. Further gain increases causes vocals to get extremely dense and thick--a great sound for certain hard rock vocalists.

If I increased the Input control to full CW, then the Output control may have to come down and its LED will start to stay on continuously. Even maxed out, Syren never got fizzy like a transistorized pre-amp.

The way Syren overloads worked well using the DI. I recorded a completely stock late model Fender Strat plugged into the front. For this particular rhythm part, I used the guitar's front pickup, crank the Input on Syren all the way up to 10, and backed the Output down to mid-way. I used the HPF, the Open mode and achieved a thick, slightly distorted guitar sound that sounds more like a guitar amp than any DI I've ever used.

Lots of Sound In a 500 Slot!

Much beyond a mic pre-amp, Syren is one of the most useful 500 modules I've seen. It offers a lot of colorful choices easily!