Test Drive: The Sony DPS-M7 Digital Sonic Modulator


by Jerry Vigil

If you've been reading your R.A.P.s, you may recall a Test Drive at the start of the year on the Sony DPS-R7 Digital Reverberator. The R7 is a very elaborate reverb unit. It doesn't provide a lot of other effects found on many digital effects boxes, but you get everything you could want in a reverb unit. Sony's DPS-M7 is also a digital signal processor, and, like the R7, the M7 doesn't try to provide every effect known to man. Instead, the M7 is the perfect mate for the R7. There are no reverb algorithms, but the M7 has some excellent algorithms which provide high quality pitch shifting, chorusing, flanging, EQ, and a few other special effects.

The DPS-M7 lists for $1,000. For the money, you get a true stereo processor designed with quality in mind rather than quantity. You get multiple effects, but the M7 doesn't attempt to use up all its processing power trying to provide twenty effects at once. Instead, the M7 uses its 32-bit signal processing capabilities to deliver high speed, high quality effects. The converter section consists of "18-bit oversampling A/D converters and 20-bit advanced pulse D/A converters with 45-bit noise shaping digital filters." To the average radio production person, this means crystal clear, multiple effects without the noise you might find on other, less expensive processors that try to do too much all at once.

Like its sister, the R7, Sony's DPS-M7 is a single rack space unit. The front panel is not cluttered with an array of knobs and switches. An extra-large, 2-line LCD display offers plenty of easy-to-read information. The three knobs on the left, next to the power switch, include INPUT and OUTPUT level controls as well as a METER switch. The METER switch determines how the two LED meters to the left of the display function. When set to "Input," the meters display input levels for each channel. When set to "Output," the obvious happens. But, when set to IN/OUT, the left LED meter displays the input level of channel 1, and the right LED shows the output level of channel 2. This is a handy way to compare input and output levels.

To the right of the LED display are six buttons and a data wheel. Considering the significant power of the M7, it's a welcome surprise to find the manual unnecessary to use the machine right out of the box. The HELP button is all the first time user needs to get started. Pressing HELP displays instructions relevant to whatever area of a program you might be in and even adequately guides the inexperienced user through editing a program. The LOAD button accesses the unit's memory. The EDIT button engages the program edit mode. The SAVE button stores edited programs in one of 256 user memory locations. The ENTER button is used to accept adjustments made to parameters, and the BYPASS button does as you'd expect. The data wheel on the far right selects program numbers and adjusts parameter values.

The rear panel of the M7 provides two sets of inputs. Choose from XLR balanced inputs or ¼-inch unbalanced. Standard MIDI IN, OUT, and THRU jacks access the M7's extensive MIDI support capabilities including real-time control of up to four parameters in each program plus MIDI program change. A couple of 9-pin IN and THRU ports are used with Sony's remote control for the M7, the RM-DPS7. The THRU port is used to connect several M7s in series, up to fifteen of which can be controlled via the remote control unit. Finally, the AC plug winds up our "external" tour of the M7. Now for the good stuff.

Like the R7, the M7 utilizes "processing blocks." The input is first converted to digital information and then passed to the first processing block, the INPUT BLOCK. This block lets you set the levels of each channel as well as the position of each channel in the stereo spectrum. A "Phase" parameter can be set to either "Normal" or "Reverse."

From the INPUT BLOCK, the digital signal goes through four effects blocks, then to the OUTPUT BLOCK before it meets the D/A converter on the way to the output jacks. These four effects blocks are where all the action takes place. The four blocks are the PRE-EFFECT 1 block, the PRE-EFFECT 2 block, the MODULATION block, and the POST-EFFECT block.