By Mark Farmer
The one thing I like about today’s electronic advancements are tools to make my job easier. An electronic chip here, a knob that scrolls, buttons to access a parameter, or a box to control feedback. Yes, I did say a box to control feedback. Leading the path, in the field, to electronically get rid of feedback is, Sabine. According to Sabine’s President, the corporation’s earliest products, were conceived pre-1990. The FBX-900 was their first digital device and prior machines were built using analog circuitry. Having used some of the Sabine products before, I knew how well this invention worked.
Features
New on the Sabine shelf are the FBX Solo series, the SL-610 and the SM-610. These little boxes measure in at 2.78” x 1.65” x 5.5”, and weigh only 9 ounces. These should list between,$350.00 $300.00. They could easily be purchased on the street for $265.00 to $320.00. Six of these will fit across a single space rack tray, available through Sabine. The SL-610 is the line or insert version and the SM-610 is designed for microphones. I chose the insert version to try out on a monitor system.
These Solo units work on the same principle of the larger Sabine products.The main goal, being to notch out a very narrow frequency bandwidth of the problem feedback. Since your monitor equalizer can’t pick the bandwidth for each frequency you are limited in that process. The Solo decides the depth of the cut, the width and frequency. Eliminating broad or wide band cuts that are common with a 31-band EQ.
The Solo’s each have six independent filters that work dynamically or in a fixed position. The fixed filters, once set, retain those frequency notches after set up. The dynamic filters, are roamers or drifting filters to catch any new feedback that may occur. Out of the box, Sabine has a default setting for 4 fixed and 2 dynamic filters. These two types of filters can also be reconfigured for a different set of fixed and dynamic filters. A very handy feature for different microphones used in a variety of applications.
First look at the front of the Solo SL-610 shows a very simple, well thought out panel. From left to right three push-buttons controlling, Bypass mode, Reset, and a Lock Fixed button. To the right of those are 12 multi-colored, recessed LED’s. The first four correspond to the input from your source material. Working from the top down, these labels help maintain the best dynamic range a clip light, -6dB, -12dB, and -18db. The middle section of lights is a two-color LED, labeled, “BY”, it indicates when the bypass button has been pushed or when the box is in Active mode. Next to the “BY” light is the “Lock” LED which monitors when filters that have been set are “fixed” until they are unlocked. Sabine recommends this be pushed right after set up. Below the “By” and “Lock” lights are the two rows of filter LED’s labeled 1-6. Each of these will light accordingly, to show that a new filter has been set.
A large concern of mine was, if using this unit repeatedly, in the same or similar environment, would it store and keep in memory the settings I had achieved. The answer is yes, with a long lasting 7 year internal battery.
Moving to the backside of the unit keeps things very simple. At the top is a small switch for bandwidth selection.Two width selections are provided,1/5 octave and 1/10 octave. According to the manual, the first, 1/5, for speech and the second, 1/10, for musical applications. After changing this switch you must unplug the unit and power up in order to make the change successful. For a power supply a “wall wart” keeps the transformer outside the Solo. To gain access to input and output, Sabine installed two high quality 1/4” TRS(tip,ring,sleeve) connectors.
Manufacturing a first rate, well designed product is a good thing, but if the manual to operate it is so difficult to read or understand that is a bad thing. This product has a extremely well thought out manual.
In Use
Monitor operation can be easy some days and grueling others. Putting my skills to the test,I had to provide monitors for a small string quartet playing with an acoustic type band. A sometimes difficult task depending on the volume level, temperature inside or out, and the type of microphones used. We were using a couple of Shure SM-81 mics over each of the four players. I placed the monitor wedges at each end of the musicians to gain an equal coverage to everyone. All I had to do was mix in acoustic guitar, keys, bass, and vocals with all four of the condenser mics. Inside not such an ordeal, outside volume tends to disappear periodically.
So, in order to gain the most volume before feedback in these two monitor wedges, I went after my Solo SL- 610. Having already done equalization with my 31-band graphic equalizer, I inserted the Solo between the EQ and console sub-master. Using the factory default settings(4 fixed, 2 dynamic) I pressed and held the Reset button to clear any settings in memory. Sabine suggests using five fixed and leaving one filter open for any problems that may arise. I then preceded to raise the volume level of the monitor console sub-master. Each feedback I heard disappeared one at a time until all six filters were set. Response time was very quick, I might add. The lower tones seemed to take just a little longer than the highs. This is not a bad feature since the higher frequency tones are much more harmful, and are quicker to bark out than the lower ones. My co-worker and I did not notice any noise or hiss introduced into the monitor system as a result of inserting the Solo unit. As the quartet played, I listened for any loss of dynamics, sound quality, or further change to the overall monitor mix itself. I heard none of these at all. I was however, after the show, able to achieve some amazing volume levels with the FBX Solo and the SM-81’s.
Summary
This is a neatly packaged product that is well designed and does exactly what it is supposed to. I would easily recommend the purchase of a few Solo’s to put in a Front of House rack. Adding a few Solo products to the Front of House rack would benefit those of you who control monitors from FOH. Once again, any tool that can assist in making any job easier becomes a priceless one.

Mark Farmer is a Sound Engineer with Live Technologies in Columbus, Ohio and a regular contributer to Pro Audio Review. Mark can be reached via the Internet at mixthat@columbus.rr.com

Product Points
Sabine Solo SL-610

Plus
+Great Manual
+ Easy to Use
+Performs just like
it claims
+No coloration of sound

Minus
-No on/off switch
-Not much to complain about

The Score
Neat little box for very little money to aid
in reduction of feedback.