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Yamaha SREV1 Digital Sampling Reverb

Shortly after the introduction of real-time sampling-reverb technology to the professional mixing community by SONY with its DRE-777, Yamaha has followed suit with its own offering, the SREV1. These units bring a new level of realism and sophistication to the art of synthesizing reverb in the recording studio.

Shortly after the introduction of real-time sampling-reverb technology to the professional mixing community by SONY with its DRE-777, Yamaha has followed suit with its own offering, the SREV1. These units bring a new level of realism and sophistication to the art of synthesizing reverb in the recording studio.
Product PointsApplications: Studio, mastering, post production, sound reinforcement, education.

Key Features: Four-channel or dual-stereo 32-bit convolution reverb processor, LCD moving fader remote, AES I/O standard with MIDI program control, CD-ROM and PC-card program storage.

Price: Mainframe – $5,499, Remote Controller – $1,499, DB-SREV1 expansion board – $1,999, analog card – $369

Contact: Yamaha at 714-522-9011, Web Site


+ Realistic high-quality reverb

+ Easy-to-use interface

+ User sampling capability


– No 96 kHz operation

– No analog I/O in basic configuration

The Score: High-end four-channel sampling reverb for studio and post applications.

The SREV1 is a convolving reverb. Classic studio reverbs rely on recirculating delays and all-pass filters to approximate natural reverberation. Convolution brings the illusion so close to perfection that it can be hard to distinguish from the real thing. Convolution, once the province of university and corporate research labs equipped with powerful mini-computers and floating-point array processors, has been brought to the great audio-unwashed through application-specific integrated circuits and Moore’s law of geometrically expanding microprocessor power.

The basic procedure is to first capture the impulse-response of a real room by triggering an acoustic pulse and recording the resulting reflections at a specific mic location. The exact arrival times and amplitudes of the discrete echoes that make up the room’s natural reverberation are stored. A dry audio source can then effectively be placed in that room by repeating each incoming sample of the source at the precise arrival times and amplitudes of each of the reflections in the room. This requires multiplying each incoming sample by each sample of the impulse response and adding the results in real-time, clearly a heap of arithmetic. Introduce additional mic locations to the picture and the amount of DSP power required for real-time operation becomes quite impressive.

A rough figure for convolving one minute of music with an impulse response of three seconds decay time at 44.1 kHz is approximately 350 trillion multiplications and the same number of additions. The art of how to excite and record the room, and the designer’s choice of how to integrate the resulting impulse-response data, are what distinguish the perceived effectiveness and sound quality of the device.

Yamaha’s SREV1 operates at sample rates of 44.1 or 48 kHz. The unit can be configured as a single four-channel machine, dual stereo machines, or a single, extended-range stereo machine. The maximum reverb times are 2.73, 2.73 and 5.46 seconds, respectively. An optional DSP expansion board can be purchased that doubles these times by adding 32 more of Yamaha’s proprietary CNV3 chips. The unit ships with four channels of AES digital I/O and two open slots for optional mini-YGDAI cards. The various option cards offer analog, TDIF and ADAT I/O. Also provided is an optional powered remote that offers four moving faders, a jog wheel and a 3.5 x 4.5-inch illuminated LCD screen.

Pressing the program key on the remote brings up a short list of “Quick Memory” programs. These are: Concertgebouw, Konzerthaus Mozart, Manhattan Center, Kings College Chapel, Nippon Budokan, Plate 1, Cello Studio 1, Avatar Studio A, Warm Wooden Church and Act City Hamamatsu. Thirty-two additional programs are provided on a factory-supplied CD-ROM with future libraries planned. Programs in “quick memory” can be loaded in about a quarter second, in contrast to those on the CD-ROM, which load in about 10 seconds. User-defined projects that contain program choices and edited settings can be stored and re-loaded via the unit’s internal memory, or thestandard PC card slot and an optional memory card.

Two levels of parameter control are selectable via pushbuttons labeled “main” and “fine.” The main parameter screen offers adjustment of the essentials: reverb time, initial delay, high and low pre-EQ, wet/dry balance, and I/O level. Any changes made in the main screen are automatically grouped and apply to all reverb channels. For individual channel control, the fine parameter screens are accessed. There the user can adjust the above parameters as well as pre- and post-reverb four-band parametric EQs. Upon returning to the main parameter screen for further group adjustment, any individual offsets that were entered at the fine-parameter level are maintained.

A final “utility” section is available for selecting machine configuration, digital I/O assignment, clock source, metering assignment, MIDI options and control of multiple SREV1s. Up to four can be operated from a single remote. Clock sources can be internal, word, AES or mini-YGDAI card. MIDI control supports program changes, wet/dry balance, and reverb level.

Users can also sample their own rooms (or reverbs) and create new impulse response files using the SREV1 mainframe in conjunction with Yamaha’s IRSampler and IREdit PC-based programs which are included on the CD-ROM. Under a PC’s serial control, the SREV1 will generate a variety of “time-stretched” pulses of varying length for room sampling in mono, stereo and four-channel modes, however the review unit did not come with the PC card and 8-pin mini-DIN cable required for this procedure.

In Use

Operation of the SREV1 via the remote is quite intuitive and I had no problem finding my way around the machine before ever cracking open the manual, perhaps because I am already familiar with Yamaha’s way of doing things by dint of experience with the company’s 02R mixer. Calling up programs and tweaking is simple and straightforward because these are real rooms; the user need not painstakingly build up reverbs through layers of daunting parameters such as diffusion, crossover points and reflection times. After setting a program’s wet/dry balance and reverb time, results are gratifying and nearly instantaneous. If the room you are using is not doing the trick, conjure up another from the list. The one nit I had with the remote was that for continuous movement of the cursor you have to keep tapping away rather than just holding down the key.

I first set up the machine in a digital four-in by four-out configuration and experimented with dry source recordings of guitar, solo voice, choir, cello and full orchestra, while monitoring in 4.0 surround. It became immediately apparent that the SREV1 is quite capable of producing very smooth, very natural, and very musical-sounding acoustic reverberation. The reverb tails sound great and are true to the source. Working in New York, I have had the privilege of working in a few of the spaces that Yamaha’s engineers have sampled, and the accuracy and usefulness of their efforts is impressive. The samples of The Cathedral of St. John The Divine, with its six-second reverb time, were very convincing, even while A/B-ing against a remote recording I made there recently. I have also worked in one of the cathedral’s side chapels and the “French Stone Chapel” sample matched my recollection extremely well. The SREV1 also includes a very nice plate sample that matches up to as good an EMT plate as I have heard.

In the process of quad-panning a mono source through the four inputs, a surprising aspect of Yamaha’s implementation came to light. A signal hard-panned to the SREV1’s left front input, for example, will result in reverb emanating from only the left front output; a signal sent to the right front input results in reverb from only the right front output, and so on. In a sense, this is equivalent to four different mono reverbs as sampled from the perspective of each corner of the room. This is in sharp contrast to other surround reverberators where a signal sent to any input will result in a reverb field emanating from all four outputs. Which approach you favor is a matter of individual philosophy. The Yamaha implementation does offer the usefulness of greater separation of sources in a mix and precise control of the reverb’s directionality though, some might argue, a less realistic presentation. A diffuse reverb can still be achieved by panning a source track among the desired inputs.

While working with the SREV1, I received an impromptu visit from my friend, Jim Anderson, who is one of the world’s pre-eminent jazz recording engineers. Jim was in the neighborhood and stopped by to play two projects he had just completed, a female vocalist plus rhythm combo, and a small ensemble with flugel horn lead. Since Jim is a regular at New York’s Avatar Studio, I could not resist trying him on the SREV1’s Avatar Studio A preset. We ran the finished two-track mix through the preset. Jim listened for a while and commented that it was definitely a familiar sound. We then tried the Warm Wooden Church preset on the vocal project, and after a quick tweak of reverb time and wet/dry balance, Jim decided he would like to use the program when mastering. It is a difficult challenge for any reverb to process a finished, full mix, but the SREV1 did quite well. Stopping the source abruptly and listening to the tail sounded like the real deal.

The review unit also came with the optional mini-YGDAI analog I/O cards. These are comparable to the cards used for Yamaha’s 48 kHz digital mixers. I found these to be serviceable, but lacking in the resolution and smoothness apparent when using the digital inputs and monitoring through my mastering-grade DAC. Pairing the SREV1 with a high-end ADC and DAC for analog I/O would be justified given the quality of its internal processing.


The SREV1 is a very accurate digital reverb. The convolution implementation is excellent and the four-band parametric pre- and post-reverb EQs offer good tone and flexibility. The unit’s 48 kHz maximum sampling rate, however, might present a limitation as high-resolution double and even triple sampling rates become more commonplace. Machines like this are not inexpensive, but only a few years ago, this level of quality and realism was not available in the recording studio at any price.


Sequoia DAW; Mytek 8×96 multi-channel DAC; EMM Labs Switchman Mk2, Dunlavy Aletha monitors.