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Reverberator pedal with spring and room sounds


$179.00 MSRP, $179.00 "street"


By Phil O'Keefe



Hand-building their pedals in Newberg Oregon USA, Subdecay has a strong reputation for making great-sounding, high-quality effects pedals. Their Spring Theory pedal is a DSP based (digital) reverberator. Designed for use with guitar, the pedal features two main modes of operation, with spring and room reverb types that can be selected via a small toggle switch.


The standard graphics of the pedal feature black paint with white lettering that is vaguely reminiscent of the traditional font type that Fender used on their "blackface" era amps, hinting at some of the sounds contained within. Otherwise identical versions with different colors instead of black (red, pink, blue, gold or silver paint and white lettering) are also available. While it is DSP based, it does not use the Belton Brick like some of its competitors.


Fig 1 Subdecay Spring Theory.JPG


Figure 1: The Subdecay Spring Theory





The Spring Theory is a fairly small and compact pedal that measures 4.4" L x 2.3" W x 1.0" H, making it an easy fit on crowded pedalboards. It has a nice high input impedance (1M Ohm), and the output impedance is a suitably low 1K Ohm. The switching on the Spring Theory is true bypass, which means the reverb "trails" are cut off immediately whenever you bypass the pedal, but the sustaining sound returns if you reactivate it fairly quickly - just as long as the Reverb and Depth knob settings are in their higher ranges. A red LED indicator illuminates when the pedal is activated via the 3PDT footswitch. It can run at 9V - 18V DC via a standard "Boss type" center negative 2.1mm regulated external power adapter. (Figure 2)



Spring Theory Side.JPG


Figure 2: The I/O jacks are side mounted, as is the 9-18V DC power adapter receptacle



A power supply is not included with the pedal - you'll need to provide that yourself. Current draw is 100 mA or less. The Spring Theory does not support battery operation. (Figure 3) The term of the manufacturer's limited warranty is three years, which is fairly generous.



Spring Theory gutshot.JPG

Figure 3: The interior of the Spring Theory. No internal controls, and no battery option




While the controls (Figure 4) look extremely simple, this is somewhat deceptive; they offer greater power than you might realize at first. There are only two knobs, labeled Reverb and Depth, plus two switches - a small toggle switch with Spring and Room settings, and the main 3PDT bypass footswitch.



Spring Theory Top.JPG


Figure 4: The simple controls of the Spring Theory belie the broad range of reverb sounds it can create



  • The Reverb knob controls the level of the reverb effect. Your clean (dry) signal is passed straight through the pedal at unity gain, and the Reverb knob adjusts the relative level of the effected signal.


  • The Depth knob adjusts the overall length of the reverb's decay - the amount of time it takes the reverberant sound to "fade away" to silence. 


  • The toggle switch selects either the Spring or Room reverb mode.



The range of the Reverb control is fairly broad, and you can dial up just a hint of reverb or quite a lot of it, depending on how high you set this knob.


With the toggle switch set to the Spring setting, the Spring Theory does a very credible spring reverb simulation. In side by side comparisons with actual amp mounted spring reverbs, as well as some of my other reverb pedals and DAW reverb plugins, it held up very well. There is plenty of "boing" and chirp to the sound, and you can adjust it so the sound is very wet and drippy - perfect for Surf jams.


As you would hope, the character of the reverb is more complex and  smoother overall in Room mode than when the Spring Theory is in Spring  mode. In the Room reverb mode, the Depth knob affects the reverb "size" drastically, going from a very impressive close-in, small room ambience, to a nearly infinitely sustaining synthetic cavern, with stops at very credible medium and large rooms, as well as small and large halls along the way. When the toggle switch is set to Spring, the Depth knob has a similar effect; changing from a spring reverb with a fast and nearly imperceptible decay time, through larger and longer decaying spring reverb emulations. The effect is similar to installing different reverb "tanks" into an amplifier with different decay and tail length characteristics. Past about 3 o'clock on the Depth knob, the spring reverbs take on a bit of a over-the-top "exaggerated" character. They retain some of the "drip" and "boingy" sound characteristics, but with an extended decay time that lingers well beyond any amp or studio spring reverb - tails of 15 to 20 seconds are achievable with this pedal in Spring mode.


With Depth knob settings past about 2 or 3 o'clock, the "rooms" also take a turn from the much more realistic simulations found at lower settings to more fanciful and unnatural sounding environments. This isn't a criticism, just a description. In fact, the somewhat less realistic tones at more extreme settings are bound to appeal to Ambient and Shoegaze guitarists due to their somewhat other-worldly character. The reverb decay times can be set considerably longer in Room mode than in Spring mode. To test out how long the near-infinite sustain really is, I dialed up a clean tone on a Fender Princeton, maxed out the controls in room mode on the Subdecay, and hit a single mezzo-forte Em strummed chord on my Duo Sonic II. After about half a minute, I rolled off the guitar's volume knob, and the reverb sound sustained on for a good five minutes before finally slipping below the noise floor of the pedal and amp. Noise is audible at the extreme levels of amplification I used towards the end of the sustain tests (yes, I tried it multiple times), but in any sort of real-world situation, it's just not going to be an issue with this pedal. The Depth knob remains in control at all times, so when the pedal is set so it is sustaining nearly endlessly, a simple roll-off of the Depth knob will reduce the decay time and size of the room, including for any signal that is already sustaining. This makes it easy to go from a highly sustaining reverb tail to a more moderate sized one quickly, at the twist of a knob, and with no lingering after-effects. The opposite is also true - you can have the pedal set to the middle of its Depth range, hit a chord or note, and as it's sustaining out, turn up the depth knob to get the tail to sustain and linger longer. I liked working the Depth knob in real-time as I played - using an Option Knob as a replacement for the Depth knob to make this easier, but the stock knobs of the Spring Theory are large enough and placed where they can be fairly easily manipulated with your toe or the side of your foot.





The Spring Theory is a well built, affordably priced pedal with way more sonic flexibility than appearances would have you believe. The Room emulation has become my favorite sounding "room reverb" in pedal format, and I really was shocked by the wide range of room types that are available by simply turning the Depth knob. The quality of both the spring and room reverb emulations are quite high, and while they can be set to very realistically emulate actual spring reverb units and physical rooms, the ability to go beyond that into more unnatural, yet still musically useful timbres and ambient textures is certainly attractive, and adds further flexibility and sonic utility to an already quite useful and excellent sounding pedal. Because of this, I can see this pedal being of use to not only Surf, Country, Jazz and Rock musicians, but also for more modern styles. In fact, regardless of the style of music you play, if you need a good reverb pedal, you owe it to yourself to check out the Subdecay Spring Theory. It's a real winner that further reinforces Subdecay's reputation for making first-rate effects pedals.




Phil\_OKeefe HC Bio Image.jpg




Phil O'Keefe is a multi-instrumentalist, recording engineer / producer and the Associate Editor of Harmony Central. He has engineered, produced and performed on countless recording sessions in a diverse range of styles, with artists such as Alien Ant Farm, Jules Day, Voodoo Glow Skulls, John McGill, Michael Knott and Alexa's Wish. He is a former featured monthly columnist for EQ magazine, and his articles and product reviews have also appeared in Keyboard, Electronic Musician and Guitar Player magazines.

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