When I first heard about the Wheatstone Vorsis line of broadcast audio processors, I wanted to evaluate them because, in the past I had specified Wheatstone audio consoles for my highest-quality broadcast facility builds. At one time Wheatstone offered the quietest, most feature-filled analog broadcasting boards on the planet. With that pedigree I assumed the Vorsis product line would be special, and it is.
Jeff Keith, the lead product design engineer for the AP-2000, had previously worked for Telos Systems/Omnia Audio. You can hear it in the AP-2000. There is an accuracy and lively feel to the sound, special to both companies’ product lines. The AP-2000 is the most complex DSP audio processor product to date. With 437 adjustable parameters it is not for the faint of heart. It is a tinkerer’s heaven! Nothing is hidden and numerical values are not arbitrary, representing actual values. Thanks to a clever, full-color GUI some of the adjustments are quite user-friendly. For example, there are equalization curves you can adjust by grabbing the graphical curve and tugging them to new peaks or valleys.
Under the hood
DSP-driven audio processors have come a long way from their analog brethren of the 1980s. Four-rack unit-high boxes crammed with vertically-mounted plug-in PC cards have been replaced with mostly empty chassis sporting a single mainboard. The underlying reason for not providing the product in a one RU chassis is mostly the need for sufficient front- and rear-panel real estate for the I/O connectors, local control and display surfaces. The main board of the AP-2000 has 10 layers, partially required to permit mixed analog and digital signals to quietly coexist and partially to control impedance for the high-speed digital transmission line traces between chips. Signal processing is handled by a DSP engine farm consisting of 18 Motorola fixed-point ICs and one Texas Instruments floating point engine. It is all tied together with a Xilinx programmable gate array logic. And the user control I/O is provided by a Broadcom five-port Ethernet switch IC that permits simultaneous control from the front-panel embedded PC as well as multiple remote TCP/IP connections to the box.
Analog audio is meticulously handled by 192 kHz clocked AKM converters which boast better than 120 dB dynamic range and –100 dB THD.
The power supply is part of the mainboard too, thus reducing manufacturing costs. This is an in-house-designed switcher using components that provide better performance and greater reliability than an off-the-shelf OEM solution. The IC packages are a mix of thru-hole devices and SMDs. For greater reliability the few components that could have been socketed are soldered in place.
So what happens if the power to your facility fails? While you should have a fast switching or truly uninterruptible dual conversion UPS protecting your computer-style equipment there still may be occasions where you’ll suffer power loss to your audio processor. The AP-2000 DSP farm boots up in a few seconds providing audio quite quickly. The single board computer for the front panel takes about a half a minute to come to life.
Acoustically the AP-2000 is very quiet. You could mount it in your studio furniture as there are no noisy cabinet flushing fans, just a small internal fan to move air around the internal heat sink for the front panel computer.
The AP-2000 ships with 50 factory presets. More can be downloaded from the Vorsis website. They cover a wide range of programming and offer some interesting sounds. Some of the dance presets do a lot with bass response, pushing the envelope. As with most presets, they are starting off points probably requiring tailoring to your specific needs and expectations. Some might be too mild while others might be a bit heavy handed. Time did not permit me to explore all of them.
One complaint I hear all the time about the other major audio processors is their inability to smoothly transition from one preset to another during day part changes. The AP-2000 seems to handle those changes gracefully, gently cross-fading from one to the other without sudden jarring changes.
Preset management is intuitive, using a Windows-style folder filing arrangement for favorites. You have unlimited remote storage for presets. You can also download and print every parameter of every preset including a comparison sheet so you can spot the differences between them. This is a unique and educational tool when trying to understand the settings and what they ultimately do to your sound.
I felt the front panel fell a bit short of expectations by providing a nice VGA color display but without touchscreen. The separate touchpad to the right is a bit awkward and sometimes frustrating to use. The USB port on the front panel is reserved for an external mouse. In practice I could not get the mouse port to work properly as it only supported older basic mechanical mice and not optical mice. Fortunately, a similar GUI, ported to Windows, is provided for remote control. It has somewhat more capability than the front-panel GUI and is easier to manipulate using a workstation or a laptop PC.
VORSIS AP-2000 Processor
Screenshot of the Vorsis AP-2000 AGC-Compressor
- Complete user control over all processing functions
- Hard-copy printout of every adjustable parameter
- Transparent sound with no preconceived coloration
- Fast-responding remote-panel GUI
- Front-panel touch pad is difficult to use
- Mouse port does not support modern mice
- No automatic de-emphasis in headphone monitor
- No simple mode for less experienced users
For information, contact Wheatstone/Vorsis in North Carolina at (252) 638-7000 or visitwww.vorsis.com. Caution! The front-panel headphone monitor output is very clean-sounding and can deliver lots of current to your headphones. In fact, I found the default output level way too high. The volume control is a bit coarse due to a very short virtual slider. The remote GUI’s slider is better. You can monitor the output of almost every subsystem to hear what it is doing to your sound including the output of the composite processing section. You can hear the results of final composite limiting and clipping before you put the processor on the air. There is, however, some silliness here. If you set your composite output to have normal FM pre-emphasis, that’s precisely what you’ll hear from the headphone monitor. No separate automatic de-emphasis is applied to it. Thus, you have to turn off pre-emphasis on the composite output to monitor it from the headphone jack with a flat frequency response. If the unit is in the air chain you won’t want to do this as it will disrupt pre-emphasis as broadcast.
Vorsis processors pride themselves as being uncolored out of the box. They have no signature sound. While one can choose from a large selection for factory crafted presets, as is the case with every manufacturer, I found I needed to modify them to get the sound I’m after. This is a more demanding chore when a box doesn’t come with its own signature sound. Also, unlike other processors, the AP-2000 does not have simplified menu and control modes. There are no basic more-or-less adjustments that automatically alter a bevy of parameters. I was told it’s on the AP-2000 wish list to add a simplified control option. While the underlying software was designed to create good results it is also easy to create an ugly sound. Some caution must be employed along with a good pair of ears.
The AP-2000 is capable of producing a very open or a very tightly compressed in-your-face sound. There are tools for recognizing and processing mostly monaural audio human speech differently to help reduce sibilance and audible peak clipping and they do work. The look-ahead distortion canceling limiter/clippers do reduce artifacts. The special bass handling processing can be tuned for intentional doubling or for a clean tight low end. You do not want to pre-process with an outboard AGC because the built-in intelligent sweet spot AGC math is linked to the compressor/limiter math to keep the processing in its sweet spot over a very wide dynamic range.
I was looking for an exceptionally open sound. So I dialed back all of the compressor/limiter functions leaving only AGC stages and final protection math in service. This resulted in some peak distortion especially with speech. You cannot depend only upon the AGC stage math to provide sufficient level control without forcing the final processing to work too hard. This is a fact of life for all audio processors, not just the Vorsis. Each stage contributes something to audio control. The Vorsis AGC is especially smart but you cannot run without some additional compression and limiting prior to the final composite processing.
There is an almost infinite amount of adjusting one can do with this processor and, with limited time to experiment, I only scratched the surface.