User Guide
If only wanting to record guitar then this -channel facility can be used in a similar way. Only, in this instance, the AMP Output on the
front panel is used to feed the direct instrument signal back into the amplier, and the microphone is used to record the amplied
guitar. This way, the clean direct guitar and the amplied guitar can be recorded on separate tracks (see diagram in the Signal
Connections section).
Monitoring Options
ISA One offers a variety of monitoring options from the PHONES section on the front panel. If wanting to access the monitoring
facility, connect a pair of headphones to the PHONES socket using a ¼” TRS Jack connector, then use the VOLUME control to set the
level. There are two basic monitoring modes, one for listening to the inputs and one for listening to a monitor mix sent to ISA One
from a desk or similar source. These modes are governed by the status of the CUE MIX switch, as follows:
Default Mode (CUE MIX switch inactive/not lit)
The signal sent to the headphones is a xed mix of all inputs, e.g. the main mic/line/inst input and either the DI instrument signal or
the EXT I/P signal. So, if a microphone is connected to the rear panel and selected by the INPUT switch, whilst a guitar is plugged
into the DI input on the front panel, a mix of the microphone signal and the direct guitar will be heard in the headphones.
Cue Mix Mode (CUE MIX switch active/lit)
Pressing the CUE MIX button activates a mode where the signal heard in the headphones is that connected to the CUE MIX I/Ps
on the rear panel. This is a useful mode if using ISA One with a desk, where a master mix of backing tracks and the signal being
recorded can be sent back to ISA One for monitoring. If working in a higher latency environment such as with a DAW, the default
mode (CUE MIX switch inactive) can be used to create a latency free monitor mix, as described below.
Creating a latency-free monitor mix with a DAW
The default mode described above can be used to create a latency-free monitor mix if using ISA One with a DAW, where attempting
to monitor the signal being recorded after sending through the host creates timing problems. In this situation, a mono master mix
from your music software can be sent to ISA One by connecting the left or right output of your soundcard or interface to the EXT I/P
on the rear panel. This signal will replace the DI input on the front panel as the second input sent to monitoring and to the ADC (if
installed). A mix of the main mic/line/inst input and the EXT I/P (both panned centrally) can then be listened to on the headphones
(with the CUE MIX switch inactive) for latency-free monitoring. See diagram in the Signal Connections section for more details.
Applications
Mic Preamp Input Impedance
A major element of the sound of a mic pre is related to the interaction between the specic microphone being used and the type of
mic preamp interface technology it is connected to. The main area in which this interaction has an effect is the level and frequency
response of the microphone, as follows:
Level
Professional microphones tend to have low output impedances and so more level can be achieved by selecting the higher impedance
positions of the ISA One mic preamp.
Frequency response
Microphones with dened presence peaks and tailored frequency responses can be further enhanced by choosing lower impedance
settings. Choosing higher input impedance values will tend to emphasise the high frequency response of the microphone connected,
allowing you to get improved ambient information and high end clarity, even from average-performance microphones. Various
microphone/ISA One preamp impedance combinations can be tried to achieve the desired amount of colouration for the instrument
or voice being recorded. To understand how to use the impedance selection creatively, it may be useful to read the following section
on how the microphone output impedance and the mic preamp input impedance interact.