Getting Started

If you are new to computer audio and guitar amp software, here is a diagram showing a typical system and some hints to help you choose an audio interface...

simplesystem

One of the most confusing elements for most of us is which audio interface to buy and is it suitable for guitar?  Here are the important questions to ask when looking for a device to get you started:

1) Does the audio interface have a high impedance instrument input?
You should be able to tell from the specification. Most interfaces do have a 'high-Z' input which is suitable for guitar. It should provide 1 Meg Ohm input impedance (almost all traditional amps are designed with this input impedance). Some interface have a slightly low high impedance input (less than 500 K Ohms) in which case it can help to use some sort of DI box or buffer between the guitar and the audio interface.

2) Does the audio interface have reliable drivers with decent latency performance?
This question is not so easy to answer. Audio interfaces generally require a software 'driver' that allows the computer to communicate with the device. Manufactures don't often publish the latency performance of the driver/device combination, partly because it is difficult to say for sure what the latency will be. The only way to discover which devices work best is to try them out, or get recommendations from people who are using that device with a similar computer to you. Download the S-Gear user manual and read the sections on setting up an audio interface.

3) Does the audio interface have inputs and outputs that will meet my needs?
If you are just getting started, you probably just need a guitar input and stereo outputs for your monitors and a headphone output. Most devices offer a microphone input. Some devices only offer audio input and they require that you use your computer outputs (or some other output device). Also you might want to get a device which has a MIDI input so you can connect your existing MIDI foot controller to S-Gear.

4) Should I get a USB or a Firewire audio interface?
USB is not the only option for connecting an audio interface to a computer, although it is probably the most common interface choice and pretty much all computers have a USB connection. The relative merits of USB vs Firewire is too complicated to get into in this post.

A typical entry level USB audio interface:

UA55

Notice the MIX control. The audio signal from your guitar gets converted to digital data, sent to the computer where it is processed by S-Gear (or some other software). The output is sent back to the audio interface where it is converted back to analogue audio. When monitoring, you need to set the MIX control to full software monitoring.

So really this is just a few hints to get you started. Get yourself a entry level audio interface (look on this forum and other places for recommendations), get familiar with using the computer with your guitar.

Good luck!

The minimum specification is an Intel Pentium 4 class processor 2.0GHz (or better) with at least 2GB RAM and 500MB free hard disk space. Most current entry-level machines will surpass this specification.

If you are getting into music production, then you should consider a fast multi-core machine, plenty of RAM and fast disk drives. As a rough guide, on an Intel Xeon 2.6GHz 4 Core machine we can run ten instances of the S-Gear plug-in under Sonar X1, with the CPU meters indicating about 40%.

It is possible to use your onboard soundcard, but chances are that the configuration will be tricky and the sonic results you get won't be great. Your best bet is to buy an external USB or Firewire audio interface. If you go for a simple entry level device, then installation and setup should be easy and you should achieve good audio quality.

If you really want to experiment with your onboard soundcard then try the following:

On Windows systems, download the latest version of the ASIO4ALL driver. This allows your regular windows soundcard to be used as an ASIO audio device.

On MAC OS X, you need to create an 'aggregate device' in order to use the on board sound devices. See this Apple support article for advice on creating aggregate devices. The aggregate device will appear in your S-Gear standalone device list.

No. S-Gear is a zero latency plug-in which means it does not add any additional latency beyond that imposed by the system audio buffer size.

Some plug-ins do add a small amount of latency (usually for look-ahead dynamics processing).

The latency of your system is determined by the audio driver input and output buffering plus whatever audio block size has been specified

Unless you have a particular reason to run at a higher sample rate, for reasons of processing capability, we recommend that you run at 44100Hz. Provided that your audio interface device has good quality filters, you should achieve good results. Choosing 44100Hz will give you maximum processing headroom and maximum disk recording capacity.

Without a doubt, some systems can sound more transparent at higher sample rates. But the reason for this might be the quality of your input and output filters, rather than the extra sampling resolution.

The audio buffer size determines how many audio samples your interface will store up before passing a packet of audio data to S-Gear. Sometimes it is configured in samples, and sometimes in milliseconds. The bigger the value, the more latency you will suffer through your computer; however, if the value is too small, then you are likely to suffer clips and pops since the computer cannot process one packet of audio data before the next arrives.

Most audio interfaces require that you select an audio buffer size from a list, rather than specify a precise value. As a quick guide, use the following settings, if the device does not offer the exact number, then pick the closest.

Milliseconds vs Samples at 44100Hz sample rate
2 ms = 88 samples
3 ms = 132 samples
4 ms = 176 samples
5 ms = 220 samples

Most Audio Interface devices will offer an High Impedance (Hi-Z) instrument input.  You can plug your passive guitar directly into the Hi-Z input.  Do make sure that if the device has a setting of line/instrument that you select the instrument setting.

Passive guitar pickups require a high-impedance input (typically 1 Megaohm, as found on the input of most guitar amplifiers) in order to produce a good signal across the frequency spectrum.  Some audio interface devices have a lower input impedance and this can reduce the liveliness of passive pickups, in such cases it can be helpful to use a high impedance buffer between the guitar and the audio interface.

In technical terms, a lower impedance input will damp the output and resonance of a passive pickup circuit.  It may not sound bad but it may lack liveliness that is achieved when plugging into a higher impedance input.

S- Gear is very sensitive to input level. We can't stress enough how important it is to set input levels carefully. Don't rely on the device metering; you need to use your ears too. Furthermore, if you have your pickups set very close to the strings, then you need to be extra careful. Fast transients that are not detected by the metering on your audio input device are likely to cause harsh clipping of the input signal, which then proliferates throughout the processing chain resulting in unpleasant overall tone.

To check your input levels, you need to listen to the audio going in and out of your interface with no processing applied. Some audio interface mixers let you do this by routing the input to the output. If you need to have S-Gear enabled, make sure that you bypass all processing (switch off Amp, Effect and Cab using the bypass buttons on the Rack Controller). Now strum some chords hard on your highest output pickup, if you can hear any clipping then reduce the input gain on your audio device. Even if you can't hear the clipping, it may still be present, so it's a good idea to lower the input levels just a little beyond the point that your cannot hear the clipping.