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Echo Digital Audio Indigo

I have headphones plugged into my laptop all the time. If they aren't being used for editing or rough mixing, I'm listening to a CD or watching a movie. While my computer's headphone amp sounds decent, it just cannot match the quality of my Sennheiser HD 280 Pro or my Grado SR-80 headphones.

I have headphones plugged into my laptop all the time. If they aren’t being used for editing or rough mixing, I’m listening to a CD or watching a movie. While my computer’s headphone amp sounds decent, it just cannot match the quality of my Sennheiser HD 280 Pro or my Grado SR-80 headphones. Not only is the quality less than what I would expect, but sometimes the volume is an issue as well. Even with the volume cranked, quiet movie dialog is often difficult to comprehend in a noisy plane or crowded coffee shop.
Product PointsApplications: Portable digital audio workstations

Key Features: PCMCIA Type II CardBus card; Windows Me/2000/XP, Mac OS X

Price: $159

Contact: Echo Digital Audio at 805-684-4593, Web Site.
Enter the $159 Echo Indigo, a compact PCMCIA Type II card that solves problems galore. The Indigo is a high-quality, two-output PC card headphone amplifier with tons of gain and exceptional sound quality.


To run on a Windows-based computer, the Indigo requires a laptop computer running Windows Me, 2000 or XP with a Type II Card Bus slot and one or two sets of headphones. To run on a Macintosh computer, the Indigo requires a G3 or G4 PowerBook running OS X 10.2 with a Type II Card Bus slot. Unfortunately there is no OS 9 support. With both Windows and Macintosh systems, the computer requires a minimum of 128 MB of RAM with 256 MB highly recommended.

The layout of the Indigo is simple: it has two 1/8-inch mini stereo jacks, a volume control and a bright blue LED. If two sets of headphones are being used simultaneously, the volume control determines the volume for both sets. The LED illuminates to signify that Indigo is working.

The Indigo provides the same broad range of compatibility with professional audio software as the rest of Echo Digital Audio’s products. In addition to the standard Windows audio APIs, Indigo fully supports direct kernel streaming, ASIO and GSIF. The card offers respectable low-latency performance.

The easy-to-use Indigo configuration panel allows the card to be quickly and efficiently configured for any situation. The panel even provides the option to “enable dummy input” since some professional audio software, such as Cakewalk’s SONAR, will not work with audio hardware that only has outputs.

In Use

The Indigo drivers installed in a breeze and the card provided flawless performance from the start. I found that the Echo Web site had more recent drivers than the CD included with the card, so I went straight to the Web for my drivers.

Several hours of listening to CDs through the Indigo revealed that the clarity and definition of the headphone amplifier in this card is far better than any I have ever heard in a computer. I was surprised at the low-end definition and clarity.

My next step was to take my computer into the studio to see how the converters stand up to critical listening through monitors in a controlled environment. Once again I was impressed. The card’s converters sound very good, with tremendous depth.

The default setting for the Indigo’s ASIO driver is 512 samples. This setting results in a latency of about 12 ms. Since I was only using the card for playback, this was always sufficient for me. For applications or users that require minimal latency, the Indigo driver provides a 128-sample buffer that results in a latency of only 3 ms. This setting is far more processor-reliant and is not practical on my system.

My one and only complaint with the Indigo is that a single volume control adjusts the volume for both headphone jacks. If two listeners are using different kinds of headphones or if they simply want to listen at different volume levels, someone has to compromise.

There are two new versions of the Indigo that are soon to be released (and possibly will already be on the shelves by the time you are reading this). The $229 Indigo I/O offers a single output but adds a high-quality, 24-bit, 96 kHz stereo input. This gives the user the ability to record without any additional hardware or power source. The Indigo DJ card has been designed specifically for DJ applications, giving the user two independent outputs, a headphone output and a line output. This allows the user to cue a mix with headphones while simultaneously playing the house mix through the card’s line output.


The Echo Indigo combines high-quality audio playback with low-latency ASIO drivers, resulting in a compact and affordable card with plenty of gain and fantastic sound.