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Ashly Protea System II 4.24PS Parametric Equalizer
By Doug Fowler
Ashly’s 4.24PS parametric equalizer is part of the Protea II family of digital products. The 4.24PS is a four channel device, with each channel featuring 12 parametric filters, low-pass and high-pass filters, 1.365 seconds of available delay, and a compressor/limiter. A Motorola DSP handles the number crunching chores. The 4.24 PS samples at 48 KHz, with input and output resolution at 24 bits.
Ashly reports 4.24PS processing latency as 1.46ms, although Smaart Live reports 1.50 ms repeatedly.
Using the 4.24PS
The 4.24PS is available only as a “slave”. This means the only way to control it is with a PC. It may be controlled with Ashly’s Protea System II software, which is a free download and supplied on diskettes with the equalizer. Another powerful control option is SIA Smaart Live, which allows system power-tweakers to perform complimentary equalization using the Smaart Live transfer function.
The control protocol for the 4.24PS is MIDI, but the only supported configuration is RS232 (serial port) from the PC to the 4.24PS. Subsequent slaves are connected via the XLR connectors on the rear.
Equalizer channels may be linked using the Protea control software or by changing the MIDI channels for each EQ channel on the front of the slave unit. This requires a paper clip or similar size/shape object in order to depress the recessed switch below each channel indicator. There are signal present and clip lights for each channel. When using the Ashly Protea control software meters are available for output level, and gain reduction.
Filter specifications, taken from Ashly’s web site are:
TYPE Parametric
NUMBER 4 x 12 (4.24PS) or 2 x 12 (2.24PS)
BANDWIDTH 1/25 octave to 3.3 octave
FREQ. RESOLUTION 1/24 octave
RANGE +10/-20 dB, 0.5 dB increments
HIGH SHELF FILTER Selectable, 6 or 12 dB/octave
RANGE 1.6 kHz to 20 kHz
LOW SHELF FILTER Selectable, 6 or 12 dB/octave
RANGE 20 Hz to 240 Hz
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Screen snapshot of the Ashly Protea control software (click on image to enlarge)
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This example shows a both a high and low shelf, a broad parametric filter at 1KHz and a notch at 7.55 KHz. Note the “delay” control in the lower left, variable between 0 and 1.365 seconds.
Compressor/limiter adjustment is via the software knobs at the left of the control surface.
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Limiter specifications:
THRESHOLD -20dBu to +20 dBu, 1 dB increments
RATIO 1.2:1 to infinity
ATTACK 0.5 ms to 50 ms per dB
RELEASE 10 ms to 1 sec. per dB
HPF 24 dB/octave
RANGE 20 Hz to 10.6 kHz
LPF 24 dB/octave
RANGE 33 Hz to 20.1 kHz
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Screen snapshot of SIA Smaart Live 4.5 in external device mode (click on image to enlarge)
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Controlling the Protea Parametric with SIA Smaart Live
Note the three “squares” at the 0dB line on the transfer function. The square on the left is the Low Shelf, the one on the right is (you guessed it) High Shelf, leaving one square in the middle. That single square represents the 12 parametric filters, stacked upon each other. Grab the middle square with the mouse (or use the keyboard
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shortcuts), pull it to the desired location and assign the desired characteristics (filter width, cut, boost, etc.).
In the Ashly external device control panel at the left of the Smaart display there is the option to control low/high pass, but these controls can’t be seen until either filter becomes the “active” filter by touching it with the mouse or “tabbing” over to it. Grabbing the triangle in the upper left activates “High Pass”, while grabbing the right activates “Low Pass”. High/Low pass are 24dB/octave filters.
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Pressing the “Sys Control” buttons yields this display (click on image to enlarge)
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Here the user may access the Hi Pass/Lo Pass controls, as well as the compressor/limiter. The compressor may be assigned either pre or post EQ.
Hands On:
Since there are no front panel controls you must use a computer to control the 4.24PS. Connect a cable from the serial port of your computer to the rear of the 4.24PS and set the switches properly on the rear to enable serial communications via the serial port. Make sure no other applications have the serial port captured, such as a modem or the Palm Pilot HotSync Manager running in the Windows SysTray.
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If you are using the Ashly control software it displays a popup window which says “Searching for first active channel”. You must configure the software to use the correct serial port, and possibly “enable communications” on the Communications menu. You must also tell the software which device it is controlling: Protea Graphic, Protea Parametric, or the VCM-88 remote VCA controller.
After communications are established, device operation is intuitive and straightforward. The user may also save “channels” and “scenes” to either the computer hard drive or the Protea itself. “Channels” refer to individual channel settings, while “scenes” refer to the settings for all 16 channels available in a linked system. Recall is just as intuitive – recall and load from the computer or the EQ.
For Smaart Live control, the external device plug-in looks different from the Ashly control software but is still quite easy to use. One minor annoyance is upon selecting a filter it is not active, but must be activated with a mouse click. First time users may find themselves assigning filters with no apparent response. Just make sure the filter is not “Out” and you’re all set.
Conclusions:
The 4.24PS is a system tweaker’s dream: 4 channels, plenty of filters, delay compensation, and compression to boot.. Plus, it is very affordable at $1619 U.S. retail, this price reflecting a decrease on the March 2001 price sheet.
Contact info:
Ashly Audio Inc.
http://www.ashly.com/
847 Holt Road
Webster, NY 14580-9103
USA
800.828.6308 (Toll Free)
716.872.0010 (tel.)
716.872.0739 (fax)
email:
sales@ashly.com
info@ashly.com
service@ashly.com
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