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Seasound Solo EX

Computer Recording System By Martin Walker
Published December 2000

Seasound Solo EX

Many musicians who record with their computer find that they need to buy and wire up separate mic preamps, guitar preamps and monitor mixers as well as their soundcard. Martin Walker tries out a product that aims to combine all of these elements in one system.

Based in California, SeaSound are a comparatively new company, but their founder Tom Oberheim is one of the most celebrated designers in synth history. Their primary focus is to "satisfy the needs of the solo recording artist and engineer," and this has resulted in a series of products described as "'personal DAWs".

So, what exactly constitutes a personal DAW? Well, project studios created for the use of a single person don't need lots of analogue inputs, since only one source is ever likely to be recorded at a time. The majority of musicians moving from traditional recording to a computer‑based solution probably won't need lots of analogue outputs either, since many of their EQ and effects requirements can be taken care of by software plug‑ins inside a MIDI + Audio sequencer. In fact, the majority of problems facing musicians moving to a computer‑based recording system are not due to a lack of inputs, but to a lack of the right sort of inputs. While synths and keyboards will happily interface to any line input, few soundcards up until recently have provided high‑quality mic preamps as well — and even those that do rarely have proper facilities for electric guitars, which not only need gain settings somewhere between mic and line sensitivities, but also a much higher impedance to avoid loading their pickups.

This is where the Solo Ex comes in. It's a two‑part system consisting of a PCI expansion card and a 2U rackmount case. The latter houses two high‑quality preamps optimised for both mic and instrument use, and a further two line inputs, any or all of which can be mixed together to make up the stereo signal that is sent to the PCI card and recorded into the computer. A separate stereo monitor buss is also available on the rackmount case for true zero‑latency monitoring of all input signals (since the signals have yet to enter the digital domain), as well as for the WAV playback signal from the soundcard portion of the package. Along with front‑panel metering, separate Master and Control Room outputs, and twin headphone outputs, the Solo Ex also has a 1‑in/1‑out MIDI Interface, S/PDIF digital In and Out for your DAT or Minidisc recorder, and full 24‑bit/96kHz support.

The idea is that the Solo Ex can replace DI boxes, mic preamps, headphone amps, soundcard, monitor mixer, and MIDI interface, and at the same time remove the need for all the cables normally used to connect them together. It's a neat solution to a situation that faces lots of musicians and, not surprisingly, it's created a lot of interest.


SeaSound thoughtfully provide a routing diagram on the top of the rack unit, showing which signal goes where through its internal mixing circuitry.SeaSound thoughtfully provide a routing diagram on the top of the rack unit, showing which signal goes where through its internal mixing circuitry.

The rackmount case is certainly eye‑catching, with a 5mm‑thick, solid aluminium front panel milled down to 3mm at the edges, leaving the central 'sculpted' section standing proud, and anodised in an attractive sea‑blue. The front panel is also awash with controls, housing a total of 18 polished aluminium rotary knobs, 15 LED indicators, five toggle switches, six sockets, and two 10‑segment LED meters. On the back panel there are a further 13 quarter‑inch jack sockets, three DIN sockets, and a 25‑way connector that attaches to the PCI expansion card. Inside the rackmount case are no fewer than four circuit boards, with the A‑D converters mounted on a plug‑in daughterboard. These are AKM's AK4524s, as also used on (among others) Aardvark's Direct Pro 24/96, Creamware's Powersampler, and Terratec's EWS88MT.

The whole thing is powered from the host computer via the PCI expansion card. This is slightly longer than most at seven inches, and includes a small transformer, IC regulator and associated circuitry to provide the voltages required by the extensive analogue circuitry and 48V phantom power for the mic inputs. There is a single connector on the card itself: this is an expansion port that connects to a further dummy backplate and 25‑way D‑type socket supplied with the SeaSound Expander, for those who need need more simultaneous channels (see the Other SeaSound Options box on page 131).

The remaining circuitry is used for clock generation, control and S/PDIF support. S/PDIF In and Out are provided via phono connectors on the card backplate, along with the interface socket to attach the rackmount case. The two connect via a supplied two‑metre‑long cable with 25‑pin D‑type connectors at both ends; apparently you can use any IEEE 1284‑compatible printer cable up to four metres long as a replacement, which might prove handy.

Around The Inputs

The Solo Ex is comparatively simple to use at the computer end, and all four inputs and outputs can be used simultaneously with low latency.The Solo Ex is comparatively simple to use at the computer end, and all four inputs and outputs can be used simultaneously with low latency.

The front panel is divided into six main sections: Preamp 1, Preamp 2, Line 1 and 2, LED Metering, Monitor Mix, and Outputs. The two Preamp sections are identical, and use a hybrid‑discrete design, although they do share a common toggle switch to activate the 48V phantom power for the mic inputs. Each provides an XLR balanced mic input socket with up to +60dB gain and a 1kΩ input impedance, and an unbalanced quarter‑inch jack with a 1MΩ input impedance, which is ideal for electric guitar or bass, or acoustic instrument pickups. A rotary gain Trim control above the sockets lets you adjust input sensitivity, and there is a useful signal activity LED that lights green when an input signal is being received, and turns red 6dB below clipping, to help you achieve the optimum trim setting.

Next in the preamp signal chain is an insert point, which appears on the back panel as a TRS‑wired quarter‑inch jack socket, followed by a Direct Output socket. The preamp signals then pass through a rotary front‑panel Level control, and on to the Record and Monitor busses (more on these in a moment). On the next panel section the unbalanced Line inputs 1 and 2 have back‑panel quarter‑inch jack sockets, provide a fixed +18dB gain, and have an input impedance of 10kΩ that is suitable for keyboards and rack effects. They both have a signal activity/peak LED and a rotary Level control like the mic inputs.

From here on, all four input channels have identical controls. The SeaSound Solo provides a single two‑channel recording buss, and each of the four inputs has a toggle switch and associated Record Ready LED. Flicking the switch upward illuminates the red LED and routes the input signal to the appropriate record buss: Preamp 1 and Line 1 go to buss channel 1, and Preamp 2 and Line 2 to buss channel 2. Each of the four inputs also has a Monitor Pan rotary control, which lets you determine its L/R position on the stereo monitor buss.

Monitoring & Outputs

The PCI card component of the Solo Ex system contains the S/PDIF digital I/O, along with a connector that attaches to the rackmount unit.The PCI card component of the Solo Ex system contains the S/PDIF digital I/O, along with a connector that attaches to the rackmount unit.

The Metering section provides two 10‑segment LED ladder arrays, calibrated from ‑40dB to ‑10dB. Using the button alongside, you can switch these between displaying the final left and right Input signal going to the soundcard, or the Output signal coming from it during WAV playback. A pair of associated LEDs indicate the current routing. A second switch and pair of indicator LEDs lets you change the meter ballistics between Peak and Peak Hold (which is useful to see if any overloads have occurred when you weren't watching). A further pair of LEDs display MIDI In and Out activity.

The Monitor Mix section contains four rotary controls: Input Ch1 and 2 let you alter the level of signals from the two record busses, while Computer Ch1 and Ch2 let you adjust the WAV playback levels coming back from your hard drive via the soundcard. You can use these four controls to balance the monitor mix between signals playing back from the computer and the signal currently being recorded. A pair of unbalanced Aux inputs provided on the back panel in quarter‑inch jack format lets you monitor one additional stereo or two additional mono signals along with the other four, although you would have to control their mix level at source. You could, for instance, use these in conjunction with the Direct Outs of Preamp 1 or 2 to add reverb or other effects to a signal being monitored, while still keeping the recorded signal dry.

The combined monitor signals are sent to three destinations in the Output section, each of which has a single stereo rotary level control. The Control Room output emerges from a pair of unbalanced quarter‑inch jack sockets on the back panel and is intended to feed a monitor amplifier, while two independent Phones outputs let you set separate levels for the two stereo quarter‑inch jack sockets mounted on the front panel. The fourth rotary control in the Output section is labelled Master, and adjusts the final soundcard WAV playback level emerging from the Master Output sockets, once again on unbalanced quarter‑inch jacks on the back panel. You could connect these to a stereo recorder for mastering purposes.

In addition to all its other socketry, the back panel has a quarter‑inch jack socket marked External Control, which is for a forthcoming product that will feature a desktop transport‑control panel that generates MMC messages to remotely control your sequencer or other software — this should create a lot of interest when it arrives! A very nice touch (and one I wish more manufacturers would provide) is a complete signal‑flow chart printed on the top of the rack, and duplicated inside the well‑written User's Guide.


Apart from the MIDI sockets, the analogue connectors on the back of the rack unit are all on quarter‑inch jacks.Apart from the MIDI sockets, the analogue connectors on the back of the rack unit are all on quarter‑inch jacks.

As always, I visited the manufacturer's web site to check on the latest driver situation before installing the hardware, and found newer version 2.2.0 drivers for my PC than those supplied on the CD‑ROM. These latest Windows 95/98 drivers offer ASIO, DirectSound, and MME support, while the latest Mac drivers are supplied in two versions: 1.3.1 for standard Macs, and 1.3.2 specifically for G4 Macs only. According to their web site, SeaSound are also currently working on Windows 2000, OSX, and Linux drivers, although no projected release dates are offered, and they also hope to release GSIF‑compatible drivers for Gigasampler users some time in 2000.

Although the latest Windows download was a hefty 1.44Mb, the single executable file also contained the latest Solo‑o‑meter utility. Whether you have a Mac or PC, installing the drivers should prove easy enough — PC owners should find that the card is automatically detected by Plug and Play, while Mac owners simply drag their driver files from the CD‑ROM to their Extensions folder as normal. You can also install the bundled version of Cubasis VST on both platforms from the supplied CD‑ROM, if required, while PC owners get Sonic Foundry's Acid Rock as well.

In Windows the Solo Ex's analogue I/O appears as SS 1/2 In and SS 1/2 Out, while the digital I/O is SS 3/4 (S/PDIF) In and SS 3/4 (S/PDIF) Out. The MIDI interface appears as Solo MIDI In and Solo MIDI Out, along with Solo Command Port Out, which I presume is used in connection with the optional External Controller socket and forthcoming desktop transport controller. The ASIO 2 drivers have their own Control Panel, which simply provides a slider to adjust buffer size anywhere between 128 bytes and 32K. These settings can provide latencies between 9mS and 749mS, depending on the capabilities of your computer.


Unlike most soundcards, the Solo Ex doesn't really require a software mixing utility, since it provides dedicated hardware knobs for each mixing function, so there are no fancy slider graphics on the supplied Solo‑o‑meter utility. Instead, this provides a versatile meter and various switched options for sample rate, clock source, and routing.

There are five signal‑routing modes that configure the PCI card for various uses. The default 'Normal' mode automatically feeds the audio sent to SS 1/2 Out to the S/PDIF output as well: any audio you send to SS 3/4 (S/PDIF) Out is ignored. 'Normal+S/PDIF' mode is similar to this, except that any signal at the S/PDIF input is also mixed in for monitoring purposes. '4x4' mode separates the two outputs so that you can send different audio signals to them both, and in this mode you can record and play back using all four inputs and outputs separately, while '4x4+S/PDIF' mode once again adds any S/PDIF input signal to the main analogue outputs. The final mode is 'Converter', which lets you use the Solo Ex as a stand‑alone converter, with the record buss signal sent directly via the A‑D converters to the S/PDIF output, and the S/PDIF Input sent through the D‑A converters to the analogue outputs.

The Solo‑o‑meter itself is a stereo LED ladder‑style array similar to that on the front panel, but with many more segments. It has software ballistics based closely on a standard PPM display, but you can also activate an optional Peak Hold facility that 'hangs on' to the peak level for a few seconds. The meter display is scaled from ‑108dB to clip point (indicated by a red LED just above the meter), and the clip detection has user‑selectable Overs that let you choose how many sample points at maximum level constitute an overload. One point could be a legitimate peak, two might be feasible in a real signal, but the default value of three is much more likely to be an overload that needs registering. Beneath the meter Clip Count displays the largest number of consecutive overs recorded, along with the current meter reading in dBs.

Unfortunately the meter only displays input level (ie. the output level of the A‑D converter) when in Converter mode. While this is useful, in all other modes it displays WAV playback level, so the Clip and Over detection is of questionable use. Also available in the Solo‑o‑meter utility is a Sample Rate setting for use when in convert mode, and a S/PDIF Slave button to switch to external clock when required. Although its graphics do seem rather garish and unsophisticated, Solo‑o‑meter does do the job, and the converter mode is actually quite useful.

In Use

The Solo Ex D‑A converters provided a clearer top end and better stereo imaging than my own Echo Gina soundcard, as well as a slightly warmer bass end, and they had considerably lower background noise. The mic preamps also sounded very natural, while I'm sure guitarists would be more than happy with the sound of the Instrument inputs. It would have been useful to have some front‑panel markings for the rotary controls and more obvious pointers on the knobs themselves, although admittedly most of the time you'll be working by ear rather than by eye.

Overall I found the Solo Ex very easy to use, as well as very versatile. For instance, the Inserts on the preamp inputs let you add hardware effects such as compression or EQ to individual signals, while the Direct Outs and Aux Inputs let you record dry while monitoring the signals with added hardware effects such as reverb, or connect a submixer to get more inputs into the system.

The PC drivers also worked well, and with my Pentium II 450MHz machine I managed a very good ASIO latency value of 12mS at 44.1kHz, using a buffer size of 256 samples. Using NI's Reaktor I also managed a 15mS latency with both the MME and DirectSound drivers, which augurs well for those with soft synths. Transfers of 16‑bit DAT tapes via S/PDIF always add dither noise, and it might be useful for SeaSound to make this a switched option in future drivers so that you can achieve bit‑for‑bit copies of existing material, but this is a small point.

My main technical disappointment was with A‑D background noise levels, which proved, on the review model, to be considerably higher than I anticipated . As you might expect, the most sensible way to measure this was with all the preamps out of circuit, so that measurements were at unity gain. However, at 16‑bit/44.1kHz the Solo Ex only managed ‑84dB RMS (the same figure as my aged AWE64 Gold card!) and, surprisingly, this figure didn't improve at all when changing to 24‑bit mode, or when changing sample rates. Given that the output noise from the D‑A converters is very low by comparison, I initially thought that I must have a faulty unit, but a second unit gave almost the same measurements. Despite the subjectively good sound quality overall, and extremely low playback noise levels, this amount of background noise during recordings will prevent you achieving any benefit from the 24‑bit converters, and makes 24‑bit recording using the Solo Ex a fairly pointless exercise.

Final Thoughts

The SeaSound Solo Ex is obviously designed to appeal to traditional musicians who may be intimidated by typical soundcard designs, and it succeeds very well in this. Being able to plug in a couple of guitars or mics, along with another couple of line inputs, and then have obvious record‑ready switches for each input and reliable hardware metering makes recording far less hit‑and‑miss than when using a typical all‑singing/all‑dancing software utility. These can be very confusing to musicians more used to hardware recorders, largely because their functions are implemented by software developers rather than hardware designers. The Solo Ex provides you with high‑quality mic preamps, basic mixing and monitoring facilities, plus a MIDI interface, and so long as you don't want to record a drum kit or complete band, it could provide you with everything you need in one handy package.

Alternatives are thin on the ground if you definitely want guitar inputs. One contender is the Echo Mona which, although rather more expensive at £799, does provide four independent mic/guitar/line inputs and six outputs, along with ADAT optical and S/PDIF co‑axial I/O, but has no MIDI. For those who are not so concerned about guitars, Aardvark's Direct Pro 24/96 at £649 has four mic/line inputs and four outputs, along with S/PDIF and MIDI I/O, built‑in compression and reverb, and you could add high‑impedance converters to the inputs for guitar use at about £20 a time. Guitarists could also consider buying a dedicated front end such as the Johnson J Station or Line 6 Pod Pro physical modelling guitar preamp, and then connecting their digital outputs to a simpler and cheaper digital‑only soundcard.

For those with personal studios who only record a stereo track at a time, but who want a wide selection of input types, the SeaSound Solo Ex could be just the job. I know that it is already selling well, and although I have reservations about the background recording noise levels, I expect it to carry on doing just that.

Solo EX: Brief Specifications

  • Mic inputs: two, +6 to +60dB gain, 1kΩ input impedance, globally switched +48V phantom power.
  • Line inputs: two, +18dB gain, 10kΩ input impedance.
  • Aux inputs: two, +0dB gain, 10kΩ input impedance.
  • Inserts: two, on mic/instrument channels.
  • Direct outs: two, on mic/instrument channels.
  • Main outputs: stereo Master, stereo Control Room, Phones 1, and Phones 2 (all with separate level controls).
  • Output levels: all at ‑10dBV with 600Ω impedance.
  • Analogue connectors: all are unbalanced quarter‑inch jacks, except mic inputs, which are balanced XLRs.
  • A‑D and D‑A converters: AKM AK4524, 24‑bit with 128x oversampling.
  • Front‑panel metering: stereo 10‑segment LED ladder arrays (switchable to In or Out signals).
  • Supported sample rates: 11.025, 12, 16, 22.05, 24, 32, 44.1, 48, 88.2, and 96kHz.
  • Dynamic range: >105dB at 48kHz.
  • THD + noise: 0.005 percent, 20Hz to 22kHz.
  • Crosstalk: < ‑95dB.
  • Digital I/O: co‑axial S/PDIF In and Out up to 24‑bit operation.
  • Supported S/PDIF sample rates: 22.05, 24, 32, 44.1, 48, 88.2, and 96kHz.
  • MIDI I/O: In, Out, and Thru.

Mac Driver Problems

SeaSound are thankfully open on their web site about some possible problems that may afflict Mac owners, largely due to the limited support for OMS in Mac OS 9. They recommend using Mac OS 8.6 where possible, since this doesn't have the same compatibility problems, and a detailed Tech Note is available on their web site detailing the issues.

The Solo Ex is compatible with all PowerPC machines with PCI expansion slots, including G4 models. However, you may apparently have problems with G4 Macs running either OS 8.6 or 9.0, with intermittent crashes or freezes on startup or when changing configuration, and startup icons not being displayed correctly. The latest Mac version 1.3.0 drivers do apparently improve stability, but haven't yet totally solved the problems. Some applications may also have problems recording and playing back on a G4 with the ASIO drivers installed, so SeaSound supply two versions; the 'modern' 32‑bit one should be used where possible, and the 'legacy' 16‑bit one if not. The Mac Solo‑o‑meter utility is also not yet fully functional.

Other SeaSound Options

For those who want more inputs and outputs, the Solo Expander adds six more 24/96‑capable channels to the Solo Ex for a total of eight discrete inputs and eight outputs. Its monitor outputs plug into the Solo Ex, providing zero‑latency monitoring of all eight channels. The two products are also available as a bundle known as the Solo Ex8, which occupies a total of three rack units.

For those who like the flexibility of the SeaSound approach, but don't need as many inputs, the new SeaSound Soloist consists of a 1U rackmount case and PCI card combination featuring one high‑quality mic preamp, one guitar preamp, and a stereo line input. It still has similar monitoring facilities to the Solo Ex, and 24‑bit/96kHz‑capable converters, and also has an identical expansion port to the Solo Ex for use with the Solo Expander and 8x8 operation. Its UK retail price should be around £499.


  • Simultaneous inputs for mics, guitars, and synths.
  • Very good playback sound quality.
  • Impressive‑looking rackmount case with lots of hands‑on controls.
  • Insert and Direct Outs for both preamps provide more versatility.
  • Useful real‑time converter mode.


  • Background noise during recording higher than expected.
  • Software meter utility only reads input levels in converter mode.
  • Some Mac driver issues still to be resolved.


The SeaSound Solo Ex is a flexible and well‑thought‑out solution for the musician who sings, plays guitar and keyboards, and who doesn't want to be blinded by science. However, the high measured background noise during recordings is a cause for concern.