Marshall Choong Audio

Product Range .....

Classic Monitors

Closed box designs for the purist using exceptional drivers and constructed using Mk-2 constrained layer damping throughout and our usual high quality plywood construction throughout.

Classic Vented Loudspeakers

A range of vented loudspeaker designs giving a more cost effective extended low frequency response. The model SC3WV has Scanspeak Illuminator drivers and uses an exterior crossover for each channel to avoid compromising the cabinet design. A choice is available for a passive crossover or an active analogue crossover with triple Class A/B amplification.

Active Closed Box Loudspeakers

The model 26W-ADS is a state of the art full range loudspeaker with multichannel external analogue active crossover intended as a benchmark and technology demonstrator. The drivers are Scanspeak Illuminator mid range and tweeter with a long throw Scanspeak Revelator bass driver.
The bass driver response is first corrected to extend the bandwidth, and then a choice of gentle roll-off's can be selected to minimise bass group delay. The unusual cabinet shape is designed to reduce diffraction effects by presenting to the listener a larger cabinet width, with 45 degree edges.

MODEL Dimensions HxWxD LF Response 3 dB, 6 dB LF Power Bandwidth Sensitivity 2.82 V Nominal Imp. Driver Dia. Bass/mid/tw Crossover type
CM-2 closed box 390 x 245 x 300 mm -3dB 80,-6dB 62 Hz 65 Hz 105 dBA 84dBA >150 Hz 7 ohms 220/----/25 mm passive
CM-3 closed box 600 x 300 x 350 mm -3dB 55, -6dB 39 Hz 55 Hz 105 dBA 82 dBA >150 Hz 7 ohms 220/150/25 mm passive
SC3WV Vented Passive 1075 x 225 x 335 mm -3dB 36,-6dB 30 Hz 34 Hz 105 dBA 80 dBA >150 Hz 6.5 ohms 180/120/25 mm passive
SC3WV Vented Active 1075 x 225 x 335 mm -3dB 36,-6dB 30 Hz 34Hz 105 dBA 0.35-1.4 V Balanced 6.5 ohms 180/120/25 mm passive
26W/ADS Closed Box Active 1140 x 370 x 340 mm -3dB 28,-6dB 20 Hz 47 Hz 105 dBA 0.35-1.4 V Balanced 4 ohms 260/150/25 active

Loudspeakers Comparisons

General Cabinet Parameters

All cabinets are constructed from best quality Latvian birch ply. Unless otherwise stated, all cabinets are of the closed box type with low Q factors between 0.5 and 0.6 where size permits. The controlled resonance of vented enclosures gives rise to excessive group delay at low frequencies which should be avoided. Fig 1. shows a comparison of typical group delays for MC loudspeakers with 180, 220 and 270 mm drivers having 3dB frequency points at 80, 50 and 40 Hz respectively.


Panel damping is used on all products with a considered compromise between panel stiffness and damping effectiveness. A comparison between typical simple damped panel cabinets and CLD is shown in Fig2. The materials used have been upgraded to the current Mk-2 specification and do not use bitumen materials, which have a tendency to flow when under pressure or pvc sheet, which is much better than bitumen but not as stable as Mk-2 damping material.
Note the panel vibration without CLD lasts for up to 300 ms. All panel areas are damped unless internal crossovers are used and the current products have an improved heavy stiffening panels.
All bracing panels use fully triangulated designs typically spaced every 180 mm of cabinet height. All panel areas are damped unless internal crossovers are used and the current products have an improved heavy stiffening panels. All bracing panels use fully triangulated designs typically spaced every 180 mm of cabinet height.


All drivers are manufactured by Scanspeak and have shorted turn technology which is important to reduce distortion across the full mid range. Critical drivers use underhung voice coils giving exceptional low level intermodulation distortion. Damped and coated paper cones are used except where a driver is used for woofer applications in which case aluminium may be specified. Neodymium magnetic materials are used when possible. All tweeters are soft fabric roll surround types with a bandwidth extended to 40 kHz.


2nd order Linkwitz-Riley crossovers are used for passive crossovers. 4th order Linkwitz-Riley crossovers are used for active design. Air cored inductors are used above 200 Hz and substantial polypropylene capacitors are specified. Above 2.7 mH, high powered, low distortion (less than 0.02%) bar inductors are used in high end designs.


MC uses real veneers on all products with a standard 0.6 mm thickness. A mixture of traditional materials and glues are used throughout with a view to using sustainable sources wherever possible. Final finishing is usually with British manufactured danish oil followed by wax polishes. Standard veneers are typically as follows: Floor standers: American White Oak Smaller cabinets: Cherry or the above


We use a gold plated screw terminal produced in the UK by Michell. We recommend the use of soldered 4 mm multiple contact "lantern" terminals produced in Switzerland by Staubli.


Instead of traditional grills, we provide transparent polycarbonate panels to protect drivers when the loudspeakers are not in use.


The amplifiers are mono with a separate amplifiers for each driver. The only passive crossover components in the system are zobel networks that correct the driver inductances. The modular construction is split into the following components:- 1. Standby supply circuitry which controls soft start and global fault shutdown mechanisms. 2. Main power supply. 3. Input equalisers, audio controls and crossover circuitry 4. Class AB amplifier circuit boards which have self contained protection. All modules with signal inputs and outputs have balanced connections. The vertical aluminium cabinet panels are used as the main heat sinks. Minimum sensitivity for full power output is 1.4 V rms balanced signal with switched gains of +3, +6, +9 and +12 dB giving 1.4, 1.0, 0.7, 0.35 V rms sensitivity. For systems with unbalanced signals, Marshall Choong will provide an active 2 channel unbalanced (phono) to XLR adapter.