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Soundcraft Sixteen into Two Mixer


Test Report on: Soundcraft "Sixteen into Two" Mixer
Date: July 1975. £1000 ex VAT.

The "Sixteen into Two" is a large "stage" mixer designed for balancing the sound of live music. Though less expensive than a professional studio mixer, it has most of the same facilities and almost studio performance. The unit is specifically designed to withstand a life "on the road" with a group and, for ruggedness, is constructed in what is called an "aluminium flight case". This is an extremely sturdy aluminium covered, plywood case with strong catches and handles and reinforced corners.

The facilities provided on each input channel are:
(i) 200 ohm balanced line microphone input via an XLR connector
(ii) input sensitivity control
(iii) 4 channel equalisation
(iv) foldback and echo (or reverb) rotary faders
(v) slider main fader and rotary left/right balance control.
(vi) monitor selection and channel off/on switch.

One echo output is provided for driving an external effects units but two echo return inputs, each with its own level control, are fitted. This permits two external effects to be used simultaneously. The echo channel has a full set of four tone controls and foldback and master echo controls.

Each of the two main output channels and the foldback channel has a master fader and bass and treble controls. A headphone monitor channel can listen in on any mixed output or any individual input channel. Two targe V.U. meters can be switched to measure the signals on the main outputs or to measure the foldback channel output on one meter and the source selected by the headphone monitor on the other.

All the inputs and outputs, apart from going to XLR connectors, also go to a single multi-spin socket so that a multi-core cable can be used to connect the mixer to a stage box. This permits the mixer and its operator to be placed out in the auditorium. A suitable multi-core cable on a dispenser, and the stage box can be provided as an extra.

Construction



Inside the sturdy outer case is a single large front panel on which all the working parts are mounted. Each of the 16 input channels has its own printed circuit board; three identical mixing boards are used for the left, right and foldback channels and two further boards carry monitor and reverb channel components; total of 21 printed circuit boards. On current units these are made of phenol bonded paper but glass fibre boards are being fitted to all new units.

Components with any significant weight are not mounted on the printed circuit boards but are directly bolted to the main panel. These include the 16 mu-metal shielded input transformers, the toroidal mains transformers, which is also in a screening case, and the smoothing electrolytics.

A lot of thought has obviously gone into the choice of components and method of construction. The slider pots have the track offset to the slot so that any dust which gets in does not settle on the resistive element and so make the pot noisy. An R.F. filter has been fitted in the mains circuit so that mains-borne interference is rejected. The mains adjuster is next to the mains input socket so it is less likely that one would forget to set it correctly. There are also numerous other small features which indicate attention to detail in the the design.

Conclusion



This is a well considered piece of engineering which will satisfactorily do the job for which it was designed. The quality of components and of construction is good and the facilities and performance well justify the price tag.

In use, one may expect to require inputs from music sources other than microphones. The manufacturers can provide special inputs on request.

TEST RESULTS

Parameter RESULTS TEST CONDITION COMMENTS
Maximum gain 66.8dB Sensitivity & fader at max, balance central. -62.8dBm input for + 4dBm output
Input Saturation -39dBm @ max ip gain Turning input control down will allow higher input levels
Max. output +19dBm Onset of output clipping this is equivalent to 7 V RMS
Input tone controls +16dB Treble @ 15KHz Input tone controls very good.
-16.8dB
+13.8 Presence @ 3KHz measured on chan. 3
-13.1
+12.2 Middle @ 300Hz
-12.5
+17.2 Bass @ 60 Hz
-15.5
Output tone controls +12.8dB Treble @ 10K Hz measured on LH chan. good
-11.8dB
+13.0dB Bass @ 60Hz
-11dB
Input Noise -126dBm 200 ohm sources, gain at max. calculated valve averaged from 7 ip chans Very good.
With input sensitivity control central the value is a little higher than this.
Residual Noise -76dBm - all input & main faders at zero Quite good but could be better. Residual signal to Noise Ratio 70dB to 80dB.
(ie mixer stage) —66dbM — input faders at zero, main faders at max. Noise measurements were taken broad band but better figures would result if measurement were restricted to audio bandwith.
Distortion 0.065% through whole system with output level of +4dBm Very good
Meters 0VU = +4dBm This is the American standard. The mixer will also work successfully into 0dBm levels





Previous Article in this issue

Wakeman

Next article in this issue

Davoli Tempest 50T


International Musician & Recording World - Copyright: Cover Publications Ltd, Northern & Shell Ltd.

 

International Musician - Sep 1975

Donated & scanned by: Mike Gorman

SoundCheck

Gear in this article:

Mixer > Soundcraft > Sixteen Into Two

Review by Bruce Gibbs

Previous article in this issue:

> Wakeman

Next article in this issue:

> Davoli Tempest 50T


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TEST RESULTS

Parameter RESULTS TEST CONDITION COMMENTS
Maximum gain 66.8dB Sensitivity & fader at max, balance central. -62.8dBm input for + 4dBm output
Input Saturation -39dBm @ max ip gain Turning input control down will allow higher input levels
Max. output +19dBm Onset of output clipping this is equivalent to 7 V RMS
Input tone controls +16dB Treble @ 15KHz Input tone controls very good.
-16.8dB
+13.8 Presence @ 3KHz measured on chan. 3
-13.1
+12.2 Middle @ 300Hz
-12.5
+17.2 Bass @ 60 Hz
-15.5
Output tone controls +12.8dB Treble @ 10K Hz measured on LH chan. good
-11.8dB
+13.0dB Bass @ 60Hz
-11dB
Input Noise -126dBm 200 ohm sources, gain at max. calculated valve averaged from 7 ip chans Very good.
With input sensitivity control central the value is a little higher than this.
Residual Noise -76dBm - all input & main faders at zero Quite good but could be better. Residual signal to Noise Ratio 70dB to 80dB.
(ie mixer stage) —66dbM — input faders at zero, main faders at max. Noise measurements were taken broad band but better figures would result if measurement were restricted to audio bandwith.
Distortion 0.065% through whole system with output level of +4dBm Very good
Meters 0VU = +4dBm This is the American standard. The mixer will also work successfully into 0dBm levels





Previous Article in this issue

Wakeman

Next article in this issue

Davoli Tempest 50T


International Musician & Recording World - Copyright: Cover Publications Ltd, Northern & Shell Ltd.

 

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