It has been a while since I make a review for an audio effect. This little yellow wah pedal was found at a second-hand store for about 20-25 euros. I’m not a fan of the Wah sound, but the Human Voice label was interesting enough to separate me from my cash. The video bellow shows how this pedal behaves when fed by the Volca Keys.
First, lets talk about build quality. As I mentioned in the Vlog, there is an evolution on the way Behringer produces stuff, with the older gear being more fragile and less well build. This pedal’s construction is a shy improvement over that of the UV300, but it is still far away from that of the RV600 and the other pedals I have from the 600 series. As usual, this pedal can run out of a 9V battery, of using a 9V center-negative pin power supply. There are 3 inputs to this pedal and only one mono output. The inputs on the right hand side are for plugging in a guitar or a bass guitar (depending on which socket is pluged, the parameters for the internal filter are adjusted). On the left side there is the mono audio output and also an input for a control or an expression pedal.
There are also four knobs on the front side: DECAY, SENS, MANUAL and MODE. As usual from Behringer, this pedal comes loaded with quite a few modes, but 3 (UP, DOWN and SYNTH) of them are just a regular Wah effect with an upward, downward or upward motion of the filter sweep (the latter adds in some resonance also). The rate at which the filter is swept is dialled in using the DECAY knob. Even more unimpressive is the fact that the pedal requires almost absolute silence to re-trigger its internal envelope, limiting the options for musical articulation to “extreme staccato” only.
Things get more interesting with the other two modes: HUMAN VOICE and TEMPO. The former is a shifting formant filter that works great on lush pads. The MANUAL and SENS knobs are used to select the initial and final vowel (pre- and post-decay). This allows not only to great vocal tones, but also to articulate diphthongs like ae, ui, oi, eu, etc… Again, the decay knob sets the time for articulating between the two vowels. Unfortunately this mode suffers from the same lack of envelope sensitivity mentioned above.
The lack of sensitivity towards the volume envelope of the incoming audio might be ameliorated by the last mode: TEMPO. In this mode, the Wah effect is controlled by an internal LFO. The velocity of which can be controlled using either the DECAY knob of by tapping in the tempo using the pedal (press and hold for 2 seconds to enter tap tempo mode) or an external switch pedal. The MANUAL and SENS knobs are disabled in this mode. This mode, combined with the LFO and VCF capabilities of the Volca allows for some very interesting drone and pad sounds with a lot of movement going on (courtesy of having two filters sweeping at different rates).
In addition to this, the DW400 can be controlled using an expression pedal, like M-Audio’s EX-P. Plugging in an expression pedal to the CTRL/EXP input disables the DECAY (and also the MANUAL and SENS. knobs in UP, DOWN and SYNTH modes). This transforms the DW400 into a simple Wah pedal. In HUMAN VOICE mode, the expression pedal now allows you to control the morphing between the two vowels. This is a more interesting way to get some vocal articulation in your music, but you have to train your foot to move in time with the audio.
Although there are two audio inputs, the DW400 cannot be used as a simple mono mixer: the GTR IN socket always takes precedence, and the BASS IN socket is only active if there is nothing plugged into the former.
In conclusion, this is perhaps not the most interesting pedal around. It lacks a little bit in build quality and the Wah effect is nothing you cannot achieve using a synth with a decent filter and ADSR envelope to modulate it. It is the HUMAN VOICE (when combined with an expression pedal) that makes this machine keep its place in my collection. They are becoming rare, and I could not find any stock left on amazon. so, if you are interested, you must dig a little bit in e-bay or in second-hand stores.