The rapidly decreasing cost of DSP power over the past few years has allowed for the evolution of a new breed of reverb: the digital sampling reverb. The technology is called “convolution processing” and entails taking sonic “fingerprints” of acoustic spaces by measuring the impulse response of the environment, similar to “shooting” a room for acoustic measurement. Time-stretched pulses are recorded via carefully placed microphones, and the resultant impulse-response data is used to “convolve” the characteristics of the recorded environment onto any audio signal. This way, in theory, the reverberant tone of any previously measured space — from the Taj Mahal to a Gold Star echo chamber — can be made available for use in a recording studio environment. The SREV1, Yamaha’s first offering in the brave new world of sampling reverbs, ships with a CD-ROM containing preset reverb programs of some well-known venues from around the world. These include the Concertgebouw in Amsterdam, King’s College Chapel at Cambridge, Avatar Studios in New York, and Cello in L.A., among others. Yamaha has plans for a CD-ROM library to be released in the near future.
A 3U rackmount unit, the SREV1 can be used as a stereo reverb or as two fully independent 2-channel reverbs with separate inputs, outputs and program settings. The unit also has a 4-channel mode for surround applications. Thirty-two of Yamaha’s new convolution chips provide the necessary horsepower for the unit, allowing for a maximum of 5.46 seconds of reverb time per channel in 2-channel mode, or 2.73 seconds in 4-channel or 2-channel x2 mode. Yamaha also makes an optional expansion board (DB-SREV1 DSP) that doubles the reverb times in all modes.
The SREV1 features 24-bit I/O, 32-bit internal processing with 48kHz internal wordclock. External wordclocks of 44.1 kHz and 48 kHz are supported and can be sourced via the dedicated BNC wordclock input, AES inputs or card slot inputs. Unfortunately, the SREV1 is not 96kHz-capable, a definite strike against it for potential users now working in a 96kHz environment or those looking to enter that realm in the near future.
Up to four SREV1s can be linked serially and controlled using the optional RC-SREV1 remote controller, which features a 320×240-dot graphical display with fluorescent backlight, adjustable brightness and contrast, and four motorized faders for parameter editing. Two AES/EBU inputs and outputs are built in, and two mini YGDAI (Yamaha General Digital Audio Interface) slots offer various analog and digital I/O options (AES/EBU, ADAT, Tascam). Inputs can be assigned to channels individually, allowing various input/output configurations.
Measured impulse-response data are combined with variable parameters, such as reverb time and initial delay, to form reverb programs, which can be stored either in Quick memories or on the Internal Card or PC Card. Up to six programs can be stored in Quick memory in 2-channel or 4-channel mode; 12 in 2-channel x2 mode. Programs in Quick memory can be recalled instantly via the RC-SREV1 remote or by MIDI program changes. Projects, which contain all of the Quick memory programs and the current program settings, provide a convenient way to manage programs and settings for a particular job. Projects can be stored on the Internal Card or PC Card.
Program editing is handled at two levels: Main parameters and Fine parameters. In the Main parameter mode, channel parameters, such as reverb time, initial delay, reverb balance and EQ, are grouped so that main parameters can be tweaked simultaneously. Fine parameter editing adds pre-convolution 4-band PEQ, post-convolution 4-band PEQ and impulse-response data loading. Reverb parameters can be edited individually or grouped. Reverb balance and reverb level parameters for each channel can be controlled individually via MIDI control data.
THE ARCHITECTURE
The architecture of the SREV1 is pretty straightforward and intuitive. The RC-SREV1 control surface displays the various program, parameter and utility pages, along with system status and signal level meters. In addition to showing parameter values numerically, reverb and EQ parameters are displayed graphically. The program title is displayed prominently, and each page is divided via tabs. In 2-channel x2 mode, two numbers and titles are displayed: one for program A and one for program B. Program numbers appear only when programs are recalled or stored in Quick memory and do not appear when they are loaded externally from a drive.
The various pages can be scrolled through with up/down and left/right cursor keys. Parameters can either be adjusted by the four faders (as assigned to their respective parameters) or with a shuttle wheel. Buttons marked +1/-1 located close to the shuttle wheel allow for incremental fine adjustments. Lately, I’ve been using a couple of pieces of gear with touch screens, so when I first powered the SREV1 up, I began by touching the various menu tabs; at the top of my wish list would be a touch screen interface. However, I found the control surface to be very responsive and easy to use. The graphic representations of curves and slopes were clear, and parameter changes were visually updated very quickly. Within a few minutes of setting the unit up, I was effortlessly cruising through the menu hierarchy.
Pages are grouped as Program, Parameter Main, Parameter Fine and Utility pages, and tabs show the titles of the pages available in each group. The Utility page contains the controls for the reverb mode (2CH, 4CH, 2CH×2), I/O routing, input and output metering, and MIDI. Other parameters include the sampling rate at which the unit is operating, Bypass On/Off and Selected SREV1. (This displays which SREV1 is being addressed in a multi-unit environment.) The obligatory Edit Status indicator shows whether or not the current reverb program has been edited since it was last recalled. The status of each of the four faders appears along the bottom of the display.
Input and output signal levels can be set on two different pages: either the Main 2 page (within the Main Parameter page) or the Meter I/O section of the Utility page. On the Main 2 page, levels are adjusted for all channels simultaneously as a group, while the Meter I/O page allows for separate control of each channel. Meters displayed on the RC-SREV1 remote include the 14-segment meters on the remote display pages, and the 11-segment meters on the Meter I/O page. The SREV1 has signal and clip meters as well, and a Peak Hold function works with all of the meters. In 2-channel mode, input and output signal levels can be metered simultaneously. In 4-channel or 2-channel x2 mode, however, either the input or output levels can be metered, but not simultaneously.
The Parameter Main section contains the controls for the Main 1 and Main 2 parameters. Basic parameters, including Reverb Time, Initial Delay, Pre EQ Low Gain and Pre EQ High Gain, can all be adjusted on the Main 1 pages. The Main 2 pages contain the controls for Reverb Balance, Input Level, Output Level and Pre EQ HPF frequency. Channels in the Main 1 and 2 pages are grouped, so adjusting any one parameter in one of the Main pages affects all of them simultaneously. Parameters can be adjusted for each channel individually on the Fine parameter pages.
In the Fine parameter section, the Reverb Time, Initial Delay, Reverb Balance and Reverb Level parameters can be adjusted for each channel individually or grouped. Pre EQ parameters, which can be adjusted for each channel individually, consist of a variable frequency HPF and fully parametric 3-band EQ. Post EQ parameters can also be adjusted for each channel individually and consist of a fully parametric 3-band EQ. In 4-channel mode and 2-channel ×2 mode, two Pre EQ and Post EQ pages are available, so adjusting parameters in a surround or dual reverb environment is fully enabled.
THE SOUND OF CONVOLUTION
On the macro level, the idea of being able to dial up various reverberant spaces is an appealing alternative in a world governed by the predictable (albeit very numerous) algorithmic options offered by some of the high-end reverbs that I’ve used over the past few years. You can’t afford to book a session at Avatar? No problem, we can bring a little Avatar to a studio near you. Of course, it’s not the same, but in terms of having various reverb “signatures” available as options, the SREV1 has a lot to offer. Even with the relatively small library that ships with the unit (as mentioned above, Yamaha is planning to release more “spaces” in the near future), there is a wide variety of choice, and the overall sound of the unit was downright amazing. The textures run the gamut from bright and plate-like to gooey and wooden. I used the unit in a number of mix situations and it was a pleasing change from my usual reverb options. I suspect that it’s only a matter of time before sampling reverbs such as the SREV1 are a common element in nearly every studio.
Yamaha Corp. of America, 6600 Orange-thorpe Ave., Buena Park, CA 90620; 714/522-9011; fax 714/522-9522; www.yamaha.com.
Composer/producer Walt Szalva owns Planet 3 Productions in San Francisco.
