442 DriveRack

Complete Equalization Management System
The DriveRack 442 Complete Equalization Management System is the latest product in the DriveRack line. The 442 is based on the same operating system as the DriveRack 480 and offers the user four inputs and four outputs on XLR connectors. Each channel has EQ in the form of a 9-Band Parametric or a 31-Band Graphic and Notch Filters. In addition the 442 features a filter set that can be used to create a Highpass, Lowpass or Bandpass filter. Dynamics processing is available on all channels with a Compressor/Limiter that emulates the classic dbx 160. The output section of the 442 offers delay, output level and phase compensation. The 442 is also capable of running dual real-time analyzers on channels three and four. A 480 master, a PC GUI, or a 480R remote can control the 442. Any combination of 480s, 481s, 482s and 442s can be controlled on a single DriveRack network consisting of up to 100 units.
The 442 DriveRack continues the legacy DriveRack series, which has been created by the company that has been redefining the standard of signal processing for more than 30 years. dbx Professional Products has created a product that caters to numerous applications in tour sound and sound contractor requirements. The 442 DriveRack was designed with the purpose and vision of providing four independent channels of processing power that includes 31-Band Graphic equalizer, as well as dbxs own industry standard dynamics processing. All aspects of the aforementioned features can be controlled by the included dbx Professional Products Interactive DriveWare software. Software updates can also be downloaded instantly from www.dbxpro.com through the RS 232 port.
4 Input and 4 Outputs 31 band graphic or 9 band parametric equalizer on every input Time Alignment Delay Compressor/Limiter on every output Multi-level Security System Separate House and Show EQ with individual lockouts Triple redundant back up of all parameters when running network, 480R and GUI
TYPE IV Conversion System Electronically balanced/RF filtered XLR Inputs and Outputs Proprietary RS-485 Control Network RS-232 PC Interface for computer display and configuration
8760 S. Sandy Pkwy. Sandy, Utah 84070 Phone (801) 568-7660 Fax (801) 568-7662 Intl Fax (801) 568-7583 customer@dbxpro.com http://www.dbxpro.com
A Harman International Company

18-0014-A 11/01

Inputs Number of Inputs: Connectors: Type: Impedance: Maximum Input Level: CMRR: Outputs Number of Outputs: Connectors: Type: Impedance: Output Transformers: Max Output Level: A/D Performance Type: Dynamic Range line: Type IV dynamic range:
Range: 4 Female XLR Electronically balanced/RF filtered >40k Hardware selectable for +30, +22, +14, dBu >40 dB typical, >55 dB at 1kHz 4 Male XLR Electronically balanced, RF filtered 120 Optional +25.5 dBu into 1k +22dBu into 600 dbx Type IV Conversion System >112 dB unweighted, 115 dB A-weighted 127 dB with transient material, A-weighted, 22kHz BW 125 dB with transient material, unweighted, 22kHz BW 119 dB typical with program material, A-weighted, 22kHz BW 48kHz Notch Filters Number: Delay Length: Dynamics Type: Attack/Release: Linking: Phase Compensation Number: Amount: Output Polarity: Miscellaneous Output Transformers: Network: GUI: ROM Upgrade: Power Requirements Watts: Dimensions Dimensions: Weight Shipping Weight:
+/-12 dB range 4 fixed per channel 340ms/channel Compressor/Limiter with PeakStopPlus Program Dependent All 4 bands are linkable One per output channel 0-180 degrees phase shift Reversible Optional Proprietary RS-485 Backbone RS-232 interface for computer display and configuration Flash upgradeable through RS-232 100-240V - 50/60 Hz - 35 Watts Height- 3.5 X Width- 19 X Depth 12.lbs. 11.5 lbs.
Sample Rate: A/D Wordlength: 24 bits D/A Performance Dynamic Range: Sample Rate: D/A Wordlength: System Performance Internal Wordlength: THD + Noise: Frequency Response: Interchannel Crosstalk: EQ Type:
112 dB unweighted, 115 dB A-weighted 48kHz 24 bits 48 bits 0.003% typical at +4dBu, 1kHz, 9dB input gain 20Hz- 20kHz, +/-0.5dB <-85dB at 1kHz, 0dB input gain One 31-band Graphic EQ per input channel, or 9 band Parametric EQ per input channel RTA can be substituted for EQ in channels 3 and 4
dbx engineers are constantly working to improve the quality of our products. Specifications are, therefore subject to change without notice. FOR MORE INFORMATION CONTACT: dbx Professional Products 8760 S. Sandy Pkwy. Sandy, Utah 84070 Phone (801) 568-7660 Fax (801) 568-7662 customer@dbxpro.com http://www.dbxpro.com

DBX DriveRack 260 Setup Guide
This thread is about how to setup and configure an active crossover and speaker processor solution for Martin-Logans. The unit we will focus on is the DBX DriveRack 260, widely recognized as an amazing value in pro-audio and DIY Audio circles. I wont go into too much detail about the DR 260, instead will point you the info on DBXs site. However, since our application is a bit non-standard, there are a couple of things Ill say about the Drive Racks here in the context of a high-end audio setup.
What is a speaker processor?
In our context it is a device that provides all of the tools needed to be able to perform cross-over duties as well as correct, align and set up your speaker in your particular room. These tools are all in one box and generally have clean, computer based user interfaces to manage the many settings. In years past, this would have been a collection of three or four boxes, all doing their work in the analog domain. Today, its all integrated in one box and all processing is done by powerful DSPs. For our purposes, we are interested in its ability to provide sophisticated crossover solutions. It can do two-way or three-way stereo. It can also do two-way stereo and a summed low-frequency output. The crossover types and slopes are all selectable, with full support of high-order crossovers (up to 24db/Octave). This allows us to have some clean cutoffs between woofer and panels if desired. Additionally, these devices are sophisticated parametric equalizers, with EQ on both the inputs and for each individual output. This allows exact corrections for each driver in the system as well as overall tonal balance or room driven adjustments. One of the most important tools is very granular time and phase controls. As timealigning drivers within a speaker is critical, as is time and phase aligning speakers to each other. Finally, it provides gain (volume) management on each input and output to ensure we have the correct volume balance across the speaker.
Here are some example conceptual configurations; 2-Way This is the typical 2-way crossover with a high pass filter sending high frequencies to the ESL and the low-pass sending bass to the woofer. This would be what youd use for straight-up replacement of the factory passive twoway
Three-Way Crossover This is a mode used when you have twin subwoofers and a strictly 2-Ch system. It allows you to set delays, adjust phase and EQ for each of the subs independently. For people doing full bass management and summing the outputs of all 5 channels, this is also the standard mode to use (or the 2x5 below). It does require an external mixer to sum the bass outputs of the 6 channels (L/C/R/Ls/Rs plus we need to add LFE) before feeding the sub
Three-way with Bass summing This is a 3-way crossover in which the low-frequencies are summed to mono and output one of the jacks ready to feed your subwoofer. Use this only if you are able to sum inputs on the sub (rare) or if its strictly a 2-CH source system. The setup is similar to the 2-way, but the woofer crossover is a bandpass (typically 60 or 80Hz to 250hz), and we add a lowpass filter for the sub woofer This mode is used as a simplified version of the 2x6, in which at least the L/R sub outputs are summed in the DR-260 before sending to the sub mixer (or the sub in a 2.1 config)
What you will need to successfully deploy a modern speaker processor is listed here. There are no shortcuts, so be prepared to acquire both the devices and the knowledge needed to best make use of them, although hopefully this guide will speed up the later. Measuring software: PCs:

Acoustisoft R+D / ETF About $150 for base, $300 with all options. http://www.acoustisoft.com/
http://www.siasoft.com/index.html Room Eq Wizard - REW Mac Software: FuzzMeasure Pro 2, only $125 http://www.supermegaultragroovy.com/products/FuzzMeasure/ All of the above require a calibrated microphone and an appropriate sound system for your PC/Mac. Figure on spending anywhere from $200 to $1,000 for mic and preamp. Here is a good discussion and recommendation guide for hardware (this applies to all the software listed above) http://support.supermegaultragroovy.com/wiki/index.php/Hardware_Suggestions

Level matching

Next, these are pro-audio devices, and therefore have balanced audio ins at pro-audio levels. Either your pre-pro has balanced outs or you will need to gain and impedance match them. Topic one will be how to hook up the DR to your existing system A bullet-proof approach is to use a Jensen transformers ISO-Max DM2-2xx http://www.jensentransformers.com/dm2xx.html Typically, you would order the DM2-2RX (RCA in, XLR out). Make sure you call them to ensure you get the right flavor of Consumer to Pro level model with the right input (RCA) and output (XLR) connectors. These are not cheap at around $190, but they are the best.
For more info than youd ever want on Balanced line technology, see: http://www.dself.dsl.pipex.com/ampins/balanced/balanced.htm And this helpful note from Rane: http://www.rane.com/note110.html
A lower cost and very effective (but only for woofers) is the active electronic line balanced system from ART, the CleanBox. http://www.sweetwater.com/store/detail/CleanBox/ But make sure you also apply this mod listed at HomeTheaterShack if you plan to use <30hz outputs from them (by default they filter <30Hz content, but theres a simple mod on the link) A bargain at $55, it not only converts from consumer to pro, it also includes gain control and will convert back to consumer in the same package, which is ideal if you amps either do not have gain control, or have line-level inputs. Another option is: http://www.aphex.com/124A.htm [Discuss Gain management into and out of the DR260 ]

Physical Setup

We will keep it simple for now and describe a straightforward 2-way crossover install to replace the passive crossover of a Monolith. I picked the Monolith for two reasons, one I have a set and two, they have external crossovers that can be disconnected in minutes. Ive posted threads about how to bypass internal crossovers on the Martin Logan Owners Forum. Step one is to make sure you have enough amps, you do have four channels of amplification, right? Good, Ill use two stereo amps as an example, first is a Sunfire stereo with balanced inputs and a solid 400 wpc into 4 Ohms of an ESL, so it will drive the panels. The other will be an Adcom GFA555 II, an old war-horse of a solid state amp with 200wpc well use to drive the woofers with. The GFA only has unbalanced (RCA cinch) inputs and no gain controls. Cabling is critical (and more complex) so careful planning is required. Which means make sure the cables match your equipments needs (and not just what I happen to list here). Assuming we have a regular pre-amp put from a processor or 2ch preamp with unbalanced RCA cinch connectors, we know what we are starting with.
Next is the unbalanced to balanced converter, it will have RCA cinch inputs as well. So a male-male RCA cable per channel is required. You likely already have that as thats what feed the amp from your pre-amp. Just use that. The converter will have XLR balanced outputs, typically requiring an XLR-Female end for cable-end. The inputs the DriveRack are females, the cable end required is an XLRMale. Order a pair of XLR-F / XLR-M cables of the appropriate length. Weve now fed the Drive rack with L/R balanced level signals. To take the high frequency outputs of the DriveRack and feed the Sunfire, which also has balanced inputs, well use XLR-F to XLR-M cables for each channel and be done with that. To feed the low-frequency amp, we will need an adaptor, as we will be going from balanced to unbalanced. For the purposes of this sample, well assume we used an ART CleanBox as our converter, as it has a nice feature that allows reconverting balanced to unbalanced. Although its quality (and bass roll-off below 30Hz, only make it appropriate for a woofer, not a panel or sub). For panels, use another Jensen. Therefore well need a total of four additional cables for this. First a Balanced XLR-F to XLR-M to feed the Art CleanBox, followed by standard male to male RCAs to feed the GFA.