Since its introduction at the 1999 AES convention, Echo Digital Audio's Mona hard-disk recording system has garnered considerable praise from personal-studio

Since its introduction at the 1999 AES convention, Echo DigitalAudio's Mona hard-disk recording system has garnered considerablepraise from personal-studio owners. Mona joins the Layla, Gina, andDarla audio interfaces as the newest professional-level, all-in-onesolution in Echo's line of cross-platform recording products.

The Mona system includes a PCI interface card and a 1Urack-mount breakout box that houses the 24-bit A/D and D/Aconverters as well as the analog, S/PDIF, ADAT, and word-clock I/Oconnections (see Fig. 1). A 15-foot cable connects the card to thebox and lets you put some distance between the converters and yourcomputer.


On the front of the breakout box are a power switch/indicator,input level displays, a headphone jack with accompanying gaincontrol, and four universal analog inputs with gain controls.There's also an undocumented ¼-inch jack labeled Remote, whichEcho says is for a possible remote control add-on.

The rear panel provides six balanced +4 dBu XLR analog outputswith matching -10 dBV RCA jacks and 24-bit S/PDIF I/O on RCA jacks,ADAT optical I/O, word-clock I/O on BNC connectors, and a DB9 portfor the cable that connects to the PCI card. The analog I/O uses24-bit, 1285 oversampling converters, and the system supportssample rates between 8 and 96 kHz.

Echo bundles demo versions of several Windows audio applicationsand an unrestricted version of Syntrillium's Cool Edit Pro SE.There's no printed documentation for Cool Edit Pro SE, though Monaitself includes a printed manual.


Before buying a Mona system, download Echo Reporter, a freediagnostic tool (see Fig. 2). (A copy is also provided on theCD-ROM that comes with the system.) Echo Reporter tests variouscomponents of your computer to determine how well it will functionwith Mona. Echo has specific recommendations for the type of systemits card will work with. The company suggests a version 2.1 PCIBIOS and a genuine Intel Pentium processor and chip set or an AMDAthlon/Duron processor with the recent AMD or VIA chip set.(Problems have been reported with certain CPUs and chip sets; seethe company's Web site for details.)

Echo also recommends that you disable your computer's systemsounds when installing and using Mona. Most system sounds have verylow sample rates, and if Windows plays a system sound while yourecord or play audio, Mona's sample-rate clock will reset. If youlock the sampling rate from Mona's console, you shouldn't have aproblem. Alternatively, you might consider using a second soundcard for system sounds.

Mona runs on Windows 95, 98, and ME; Mac, Windows NT/2000, andGigaSampler (GSIF) drivers are in beta. BeOS drivers are also indevelopment. The system supports ASIO and DirectSound, and itshould work fine with any Windows audio software. The company has asoftware-compatibility list on its Web site and an extensive FAQabout the system and its operation.

I had no trouble installing Mona on my Pentium III/700 MHzmachine running Windows 98 SE. I popped the card into an empty PCIslot and connected it to the breakout box. When I rebooted, Plugand Play worked its magic, and I was all set.


With the exception of analog input levels, which are set on thebreakout box's front panel, Mona's parameters are controlled withthe included Echo Console software. Console provides a singlescreen of faders and buttons that let you set output levels, selectsynchronization settings, and adjust input monitoring (see Fig.3).

Echo Console is divided into three sections: inputs, monitors,and outputs. Inputs are represented as six meters, two for eachinput pair and S/PDIF left and right. Below each set of inputmeters is a corresponding set of monitor controls. You can adjusteach input channel's gain, and each channel can be muted, soloed,and panned. Also, you can gang the faders in each pair.

The most powerful monitor feature is the ability to establishindependent input-monitor mixes for each output. For example, youcould monitor input pair 1/2 at -12 dB through output pair 1/2, at0 dB through output pair 3/4, and at +3 dB through output pair 5/6.This capability is especially helpful if you use Mona without aseparate mixing console.

Echo Console also lets you set sync options. Mona can slave toword clock, S/PDIF, and ADAT. It can also generate those syncsignals and even translate one clock format to another. Becausethere is no MIDI I/O, SMPTE/MTC sync isn't provided.

There's one additional sync option called Esync, which is aproprietary clock signal that lets you lock multiple Mona unitstogether to expand your available audio connections. In fact, youcan lock together any number of 24-bit Echo cards (Mona, Layla24,Gina24, or Darla24) using this option—all you need are slotsto put them in.


Mona's universal inputs are very versatile. In fact, Echo callsthem universal because they accept any type of ¼-inch or XLRconnector and any analog source, including mic, line, and guitar.When you connect a mic with an XLR jack, Mona activates a built-inmic preamp (which is nice and quiet) automatically, and the gainrange of the input's accompanying trim knob is 20 to 60 dB. Inaddition, the input impedance of the mic pre is 1.5 k□. Monacan provide phantom power at the flip of a switch but only does soglobally. That means if you have one mic that needs phantom powerand another that doesn't, you're stuck. Typically, that is aproblem only if you use a ribbon mic.

Inserting a ¼-inch connector deactivates the mic preamp andinserts a line-input amplifier. If you use a TS ¼-inch plug,the connection is unbalanced; if you use a ¼-inch TRS plug,the connection is balanced. In either case, the trim-knob gainrange is 0 to 40 dB, and the input impedance is 10 k□. Thisimpedance is too low for nonactive guitar pickups, so Mona providesa Guitar switch for each input. When activated, the Guitar switchchanges the input impedance to 107 k□, and the trim-knobrange becomes 10 to 50 dB.

My only gripe about the inputs is that there aren't enough ofthem, especially for live recording. At one point I had a leadvocal, a background vocal, a guitar, and a bass connected to Mona,and that left no room for other inputs, such as synths orelectronic drums. There are some work-arounds without adding asecond or third Mona. For example, you could premix several sourcesat your mixing console and then connect the console's output to twoof Mona's analog inputs. Alternatively, if you have a mixingconsole with S/PDIF output, you could premix through it and stillhave the four analog inputs free.

I don't have a digital console, so I used my DAT deck as awork-around. I connected my mixer's analog outputs to the DAT'sanalog inputs and then connected the DAT's S/PDIF output to Mona'sS/PDIF input. That gave me a flexible stereo mix in which I couldinclude drums and synths, and I still had the four Mona inputs freefor other instruments. Of course, the drums and synths had to bepremixed, and I was relying on the quality of the A/D converters inthe DAT deck. But with a little ingenuity, Mona can be quiteflexible.


I tested Mona using a variety of applications, including SonicFoundry's Sound Forge, Steinberg's Cubase VST, Syntrillium's CoolEdit Pro, and Cakewalk's Pro Audio—with nary a problem.Windows treats each of Mona's I/O pairs as a separate sound card,so you can easily assign tracks to individual inputs and outputs.In digital-audio sequencers that provide virtual mixing consoles,such as Pro Audio and Cubase, Mona's output pairs show up asseparate mains. I recommend you set the output levels in EchoConsole and control them from your sequencing software.

I like Mona's flexible I/O options. You can use analog I/O andS/PDIF (but not ADAT) simultaneously, and the S/PDIF connectionscan handle up to 24-bit resolution. But I did run into a problemwhen I connected the S/PDIF output to my DAT deck so I could usethe DAT's meters to monitor the signal. My DAT is a consumer model,and Mona was transmitting data in the Professional (IEC-958 Type 1)format, so the DAT didn't recognize the signal. After I opened EchoConsole's Preferences dialog box and changed the S/PDIF outputformat to Consumer (Type 2), I was up and running. Mona alsoignores the SCMS copy-protection bit.

Mona's sound was excellent, regardless of which outputs Imonitored. Even the unbalanced RCA connections provided amazinglyclear audio.


Most of the minor problems I had while working with Mona wereeasily remedied, though I wish it had more inputs. Perhaps if theinput meters on the breakout box's front panel were eliminated(meters are in the software), there would be room for at least twomore inputs.

Aside from that, though, I enjoyed putting Mona through itspaces. For a personal studio, Mona is useful and convenient. Forsmall sessions or multitrack hard-disk recording, it's anall-in-one solution. A separate mixing console isn't reallynecessary, and without one, there's less noise in the signalchain.

Mona provides high-quality, clean-sounding analog and digitalaudio, a variety of sync methods, and 24-bit resolution, all in asleek-looking, 1U rack-mount box. Even at $995, that is one heck ofa deal.

Mona 24/96 Specifications

Frequency Response 10 Hz-22 kHz, ±0.25 dB Dynamic Range 110 dB (A-weighted) on inputs; 116 dB
(A-weighted) on outputs Total Harmonic Distortion 0.001%, 20 Hz-22 kHz Analog Inputs (4) universal inputs providing balanced XLR,
balanced ¼" TRS, and unbalanced ¼" jacks A/D/A converters 24-bit, 1285 oversampling Analog Outputs (6) +4 dBu differentially balanced XLR
and -10 dBV RCA outputs with 24-bit, 1285
oversampling D/A converters Digital I/O S/PDIF (up to 24-bit), ADAT optical Other I/O word clock (BNC), computer (DB9) Dimensions (breakout box) 1.75" (H) 5 17" (W) 5 5.5" (D) Weight (breakout box) 5 lbs.

Minimum System Requirements

Mona 24/96
Pentium CPU (or AMD Athlon with KX-133 chip set) with PCI 2.1BIOS;16 MB RAM; Windows 95/98/ME


Echo Digital Audio

Mona 24/96 (Win)
digital audio interface


PROS: Excellent sound. Universal analog inputs. Balancedconnections. Multiple synchronization options. Futureexpandability.

CONS: No printed documentation for included software. Not enoughinputs. Older AMD and Cyrix microprocessors may not becompatible.


Echo Digital Audio
tel. (805) 684-4593