Why do small recorders have two sets of recording level controls?

[lowpass]

I have several portable audio recorders. To adjust recording volume, there are two sets of controls:

The coarse control is in the menu or a side switch somewhere, and sets the input sensitivity to high, medium, or low. The other set is fine control and is a pot on the front of the device.

In contrast, a traditional audio mixer has only one set of control sliders and are quick to adjust. Why do portable digital recorders need to have two sets, making it more inconvenient and slower to adjust the recording volume?

One example would be tascam DR60 mark II, but many models have this same "feature".

[Martin Walker]

hi lowpass, and welcome to the SOS Forums!

I'm not sure more traditional mixing desks do only have a single control - most will have a gain control near the beginning of the signal path and then an output fader near the end of it.

In this respect this is very close a small recorder, which instead of a fully variable gain control provides two or more switched sensitivity settings, to suit microphones, instruments or line level inputs, and then the output fader or rotary control.

Normally the gain switch only needs setting once to suit whatever type of input signal you're recording and then you use the slider/rotary control to determine the final level being recorded.

Martin

[MOF]

Nor does this twin microphone preamplifier, the trim control isn’t detented.

https://www.google.co.uk/amp/s/www.soun ... -two%3famp

[Tim Gillett]

...One example would be tascam DR60 mark II, but many models have this same "feature".

What does the Tascam DR60 mark II user's manual say about the purpose of each and how to use them?

[Hugh Robjohns]

In contrast, a traditional audio mixer has only one set of control sliders and are quick to adjust.

Your observation about a traditional audio mixer is inaccurate.

Most mixers have a mic/line or pad 'coarse sensitivity' switch, or physically separate input sockets for the different input types, as well as a rotary control to adjust the preamp gain, and a linear fader (control slider) to adjust the preamp output level.

The reason for the sensitivity pre-selection -- however it is performed -- is because different types of signal source have very different impedance requirements, and generate very different ranges of signal voltage. Most practical preamps have a limited dynamic range, so some pre-conditioning is usually required to optimise gain structures for the best noise floor and headroom with different sources.

For example, a balanced microphone typically requires an input impedance of about 2k Ohms, and generates a signal voltage somewhere between about 0.002 and 2.0 Volts (peak to peak).

In contrast, a line source expects an input impedance of 10K Ohms and nominally delivers around 2.0 Volts but it could be as high as 34V (peak-peak).

The input sensitivity switch configures the preamp appropriately for these wildly differing signal ranges and impedance requirements. It may also arrange suitable microphone powering as well...

In the case of the Tascam, the switch selects the appropriate impedances, power, and conditions the input signal level for the preamp, with the rotary control serving as the gain control and/or the fader (control slider)