Dynacord DLS 223

Nick Magnus takes a look at the digital incarnation of Dynacord's popular CLS 222 Leslie Simulator.

There is a vast array of acoustic instruments and devices that manufacturers over the years have attempted (with varying levels of success) to emulate electronically. The acoustic piano is one such classic example, but a similar chestnut is that device beloved of organists, the rotating speaker cabinet, or Leslie, as it is generically known. This device is a large cabinet with a rotating bass speaker and treble horn driver that produces what is best described as a mechanical chorus effect. The sheer size and weight of the real article has made the need for a lightweight, portable version something of a Holy Grail.

Four years ago, Dynacord created such a device: the CLS 222, a 1U, analogue 19‑inch rackmount device that has gained a devoted following amongst those in the know. (For a full review see SOS, December '92.) It had a minimum of controls and no MIDI, but performed its single task with an authenticity so far unequalled by any other available simulation, as its fans would be quick to agree. It also had a reasonably hefty price tag to make up for the missing kilograms.

That model has now been discontinued; enter the DLS 223, an updated digital version with a reduced price and a not inconsiderable MIDI spec in tow. It sports no less than 46 editable parameters, all of which are controllable by MIDI events of one kind or another. Practically everything is MIDI controllable, in fact, bar the power switch.

Going Digital

Where the physical appearance of the CLS 222 was reminiscent of studio outboard gear produced in the '70s, the DLS 223 is altogether more '90s and 'digital', with a sleek black case adorned with input and output level knobs, input level meter, 14 push buttons, a 2‑digit LED readout, rotary movement monitor and a detented Alpha dial for parameter selection and editing. The rear panel is simple enough, with stereo inputs (summed to mono), high or low input level selector, stereo outs, MIDI In Out and Thru sockets, and mains Euroconnector. Also included are two sockets for optional footswitches to bypass the effect and switch rotor speeds respectively. A ground‑lift switch to eliminate earth loops is a welcome addition.

The basic editing parameters of the unit are accessible from the front panel switches, and are as follows:

• Distortion
• Room size
• Rotor balance
• Bass speed
• Treble speed
• MIDI channel.

To edit any of the three programs, simply press the button of the desired parameter and its value is shown in the LED display, ready to be altered via the Alpha dial. The altered sound is then storable to one of the three program locations. While we're on the subject of program memories, three seems rather a small number considering the vast sound editing potential of the DLS 223. There are in fact 15 ROM presets, the first three of which are factory set to occupy the three user‑programmable locations. These ROM presets are hidden in the Options menu, but any of them can be loaded into the user programs, thus erasing any of your own presets you may have stored there. On the software version of the review model (V1.0) dumping of user programs via MIDI is not a matter for the squeamish, but this problem is addressed on versions 1.1 upwards. More on this later.

The Options menu allows access to the more esoteric parameters offered by the DLS 223. This menu is reached by pressing the Speed Bass and Speed Treble buttons for three seconds (there seems to be no room to mark this on the panel), whereupon the LED display shows a parameter number. Alternately pressing Speed Treble and Speed Bass displays the value of the parameter and the parameter number respectively, and values are, of course, changed with the Alpha dial. For my personal taste, the dial on the review model lacked a positive feel — extra care is needed when setting values. I would have preferred the detented clicks to be a bit firmer.

Due to the large number of parameters available, I found it necessary to have the manual to hand at all times. One solution to this inconvenience might have been a pull‑out menu card similar to the ones found on Yamaha's TX802 module. To describe every parameter would make for tedious reading, but a number are worthy of comment. (For a full list of available parameters, see 'Option Menu Editable Parameters' box.)

• DISTORTION: While no match for a valve preamp, the distortion on the DLS 223 is roughly equivalent to that found on the Hammond XB2, or a little better, if anything, as it colours single notes. Despite a slight digital fizziness, it is quite usable in the absence of any alternative.
• ROOM: Dynacord's implementation of room ambiences is both clever and interesting: the amplitude of the room actually modulates with the speaker rotation, becoming louder as the speaker turns to face the 'back of the room'. This takes into account that in this backward‑facing position, the room reflections will be heard in preference to the direct sound. There are 15 room sizes on offer, or the effect can be switched off.
• ROOM BACK LEVEL: The relative balance of speaker/room levels is adjustable individually for the bass and treble speakers, as are many of the parameters.
• ROTATION DIRECTION: The speakers can either rotate in the same direction, or one can be made to rotate counter‑clockwise with respect to the other. Neat.
• VIBRATO EDGE: This varies the waveform of the rotation in 15 steps between triangle and trapezoid shapes. This can be seen as a way to emulate differing microphone placements — a triangle wave is like one mic, trapezoid is like two mics 120 degrees apart. As with many of these features, experimentation at both fast and slow speeds is in order to obtain optimum results.
• FRONT/BACK: Unlike the CLS 222, which merely panned the speakers from side to side, the DLS 223 also includes amplitude modulation to simulate front‑to‑back speaker movement, effectively reproducing four positions — right, front, left and rear — in succession. When this parameter is set to zero, the left/right pan dominates.
• CROSSOVER FREQUENCY: I find this parameter a bit of an oddity. The crossover frequency operates on both speakers together, and can be set to between around 500Hz and 7KHz. However, the rolloff on either side of these figures is (to my ears) too gentle, resulting in a considerable overlap of frequencies common to both speakers. The frequency separation between the speakers on the CLS 222 was far more distinct, and more akin to the Leslies of my acquaintance. I can't help feeling that a better solution might have been a low‑pass filter with adjustable cutoff frequency for the bass speaker, and a similarly equipped high‑pass filter for the treble. Dynacord have since informed me that this would require more lines in the software than are currently available.
• EQUALISATION: A fairly comprehensive, 6‑band, active equaliser together with a passive (subtractive) 3‑band EQ gives reasonable tonal control, with the passive section being on the input. The 6‑band active section is placed after the distortion circuit but before the crossover, so all equalisation takes place before the rotor effect. I found the 48Hz band perhaps of limited use, and would have found a band at 400‑500Hz a more useful sound‑shaping tool. However, Dynacord claim to have based their choice on detailed analysis of real rotary cabinets, and since they intend to remain faithful to the original items, one must bow to their judgement.
• COMB DELAY: This seems to affect the perceived colour and shape of the tonal modulation, and is most noticeable with a boost applied at 1500Hz.
• MIDI IMPLEMENTATION: MIDI control of the DLS 223 is certainly complete. All editable parameters can be controlled by system exclusive messages. A full list of SysEx codes is provided in the manual to enable the user to create, for example, a Cubase MIDI Manager page for real‑time control and editing. Similarly, you could use a hardware SysEx generator such as the ones made by Peavey to do the same job. If that's too daunting a prospect, the basic front panel controls can be assigned to respond to almost any kind of MIDI event, such as any controller, or even note numbers. (See box for a list of the possibilities.)

Assignment of these functions is assisted by a neat Learn Mode; simply press MIDI and the function you wish to assign, tweak the controller on your keyboard, and it's memorised. All such settings are global and retained at power‑off. More than one function can be given the same controller. I found it useful during editing to assign Rotor Balance to the mod wheel so I could 'solo' one or other of the speakers while adjusting its settings.

One major gripe hinted at earlier concerns the dumping of user programs via MIDI. On software version 1.0, there is no simple 'dump' command; in order to dump to or from the unit, one has to choose between a bewildering variety of SysEx command strings provided in the manual and write the appropriate instructions into a sequencer... Yeuch! Thankfully, as of version 1.1, this is all changed; simply selecting one of the three presets from the front panel dumps its data automatically from the MIDI Out socket. Reloading a preset is just as simple: the data goes into the edit buffer and can be stored in one of the three presets as normal.

Conclusion

You're probably wondering whether the DLS 223 is a worthy successor to the CLS 222. Sonically, I enjoy them both enormously, but they are different. Each one has qualities of its own, the 222 having a deliciously liquid sound while the 223 has a wider frequency response and the authentic 'mic position' possibilities. It must be said, however, that a device can sell itself (or not) on the strength of its presets. Those found in the review model were of questionable taste, being rather inaccurate and 'effecty' representations of what many people would expect from this unit. That is not to say that the more bizzarre sounds possible on the 223 are not useful; the creation of some outrageously psychotropic autopan effects was proof of that. My initial disappointment at the lack of 'real' Leslie simulations on powering up was allayed only after diving into the edit functions and restoring some sanity. Version 1.1 sees the addition of three replacement presets with a further three to be included in version 1.2.

Be assured, though, that the 223 is capable of producing astonishingly realistic rotary speaker sounds, despite what some of the presets may suggest. The opportunity to really fine tune the sound is also one of the unit's great strengths. The manual, on the whole, is perfectly presentable, although a section on Leslie miking techniques might serve as a useful guide to setting up the machine. The improvements provided on versions 1.1 upwards should turn an excellent unit into a brilliant one, the most important factor being the need for more authentic presets, especially in the first three programs. While 222 owners may or may not not be motivated to swap over, the DLS 223 is a capable and satisfying alternative to 100Kg of strangulated hernia. It is sonically a winner with no current competition in its class.