In this guide: The short answer · The three ranges · Apart MASK · Martin Audio CDD · Optimal Audio Cuboid · Comparison table · Larger models · How to choose · Matching subwoofers · Popular picks · FAQ

The short answer

All three ranges are passive, two-way surface-mount boxes for bars, restaurants, shops, gyms, hotels and similar spaces. They differ in character more than quality.

• Biamp Apart MASK is the installer’s choice for small and mid-sized rooms: the 4″ and 6.5″ models are IP64, come with a ClickMount bracket that takes the wiring, and the CT versions switch between 100V line and low impedance. The MASK6C and MASK6CT are the MASK models we sell most.
• Martin Audio CDD uses a coaxial driver whose coverage is wide close to the speaker and narrower further away, so level stays more even front to back. From 5″ to 8″ it has the highest published sensitivity and maximum level of the three, it runs from 5″ to 15″, and has weatherised WR and 100V TX-WR versions. Choose it when music quality and throw matter.
• Optimal Audio Cuboid covers 3″ to 15″. The small ABS models (3, 5, 6) have a very wide 130° x 120° pattern, come with a wall bracket, and reach IP54 with an optional terminal cover. From the Cuboid 8 up they become wooden cabinets with compression drivers and a rotatable horn (90° x 50° on the 8 and 10, 80° x 50° on the 12 and 15), for longer throws.

For a speech-and-background system on a 100V line, look at the MASK CT, Cuboid TX and CDD TX-WR models. For a low-impedance music system with a sub, any of the three works; the choice comes down to throw, looks and budget. How many you need is covered in install speakers: how many you need.

The three ranges at a glance

Before comparing numbers, it helps to know how each maker’s specs are measured, because the conventions differ:

• Sensitivity. Biamp quotes both 1W/1m and 2.83V/1m. Optimal Audio quotes 1W/1m. Martin Audio measures at 2.83V in open (4pi) space at 2m and refers it to 1m. For an 8 ohm speaker 2.83V is 1W, but the different test methods mean a 1 or 2 dB difference between brands is not meaningful.
• Power. Biamp gives continuous power handling; Martin Audio and Optimal Audio give AES rated power. Peak figures are four times the continuous or AES figure for all three.
• Maximum SPL is quoted at 1m, continuous and peak; Martin Audio states that its figures are calculated.
• Coverage is Biamp’s nominal beamwidth or Martin Audio’s and Optimal Audio’s -6 dB dispersion, horizontal by vertical.

If these terms are new, reading a speaker spec sheet explains them.

Biamp Apart MASK (Desono MASK)

Biamp now publishes these under its Desono name; we list them as Biamp Apart MASK. All are passive and sold in pairs. The C models share one design: a coated paper woofer with a 1″ soft dome tweeter, IP64 to IEC 60529, waterproof connector sealing, an integrated spirit level, self-resetting overload protection, and the patented ClickMount bracket. The wiring terminates at the bracket and the speaker clicks onto it, which Biamp says was designed with the installer in mind.

• MASK2: a 2.5″ single-driver mini satellite, 35W at 8 ohms, 110° x 110°. It is IP60 and indoor only, comes with a turn/tilt bracket, and Biamp pairs it with the SUBLIME subwoofer and recommends a 150 Hz high-pass. A MASK2CMT ceiling mounting tool is optional.
• MASK4C and MASK4CT: 4.25″ woofer, 50W. The 4C is 8 ohm only with 100° x 80° coverage. The 4CT has a tap switch for 100V (20, 10, 5, 2.5W), 70V or 16 ohm low impedance, and Biamp quotes it at 100° x 70°.
• MASK6C and MASK6CT: 6.5″ woofer, 150W, 100° x 50°. The 6C is 8 ohm only. The 6CT switches between 100V (60, 30, 15, 6W), 70V and 16 ohm. Both come in black or white; the 6CT also in white.
• MASK8F: 8″ woofer and 1″ dome on a waveguide, 200W at 8 ohms, 100° x 100°. Unlike the C models it is an indoor MDF cabinet with Speakon and binding-post inputs, supplied with U-brackets and a safety cable. Biamp lists no 100V version.

The ClickMount bracket and a safety cable come with every MASK4C, 4CT, 6C and 6CT. Optional brackets include the MASKCL 90° bracket and the MASKCV two-speaker cluster bracket; Apart’s own manual says these MASKC brackets are for indoor use only.

Martin Audio CDD

CDD stands for Coaxial Differential Dispersion. The tweeter sits in the centre of the woofer, so both come from one point, and the horizontal coverage varies with distance: Martin Audio quotes the CDD6, for example, as 110° to 80° horizontal. The wide part covers listeners close to the speaker and the narrow part throws further, putting relatively more output at the back of the room. Martin Audio says this gives more even front-to-back coverage than a fixed pattern. The driver can be rotated for landscape or portrait mounting.

• CDD5: 5.25″ coaxial, 100W AES, 90 dB, 110 dB continuous. ABS cabinet, supplied with a wall bracket; a CDDCB5 ceiling bracket is optional.
• CDD6: 6.5″ coaxial, 150W AES, 91 dB, 113 dB continuous. Composite cabinet; Martin Audio describes the wall and ceiling brackets as optional, such as the WB6/8 wall bracket and CDDCB6/8 ceiling bracket.
• CDD8: 8″ with a compression driver in the centre, 200W AES, 94 dB, 117 dB continuous, 110° to 80° by 60°. Brackets optional (the same WB6/8 and CDDCB6/8).
• WR and TX-WR versions: weatherised to IP54 with a powder-coated steel grille and a weatherproof input panel cover. Martin Audio rates them for outdoor use where they are sheltered from direct exposure to the elements. The CDD5TX-WR adds a 100V transformer (25, 12.5 or 6W) and comes with a weatherised pan-and-tilt bracket. The CDD6TX-WR taps at 50, 25 or 12.5W on 100V. The CDD8-WR, 10-WR and 12-WR are low impedance only. Martin Audio also makes CDD8TX and CDD10TX transformer versions, with and without WR, which are not in our current listings; ask us if you need one.

Every CDD model is 8 ohms nominal and comes in black or white as standard, with any RAL colour to order. Martin Audio says the CDD should be run from a controller or amplifier with suitable limiter settings, and offers DSP presets for its own DX controllers and iKON amplifiers.

The CDD-LIVE models are a separate, self-powered range aimed mainly at live and portable use, and are not covered here.

Optimal Audio Cuboid

Cuboid is really two families with one name.

• Cuboid 3, 5 and 6 (3, 5, 6): ABS cabinets with a silk or PEI dome tweeter on a shallow waveguide, 130° x 120° coverage, and a wall bracket included. They are IP54 only with the accessory terminal cover fitted (outdoor connector cover). Black or white.
• TX versions (3TX, 5TX, 6TX): the same speakers with a transformer and a rear rotary switch for 100V, 70V or 8 ohm operation. On 100V the 3TX and 5TX tap at 15, 10, 7.5 and 5W; the 6TX has what Optimal Audio calls an improved 60W transformer, with taps of 60, 30, 15 and 7.5W.
• Cuboid 8, 10, 12 and 15: trapezoid wooden cabinets, a compression driver on a rotatable horn, NL4 and Euroblock inputs. Coverage is 90° x 50° on the 8 and 10, and 80° x 50° on the 12 and 15. Brackets are sold separately, such as the WB1 wall bracket or UB1 U-bracket for the Cuboid 8. Optimal Audio quotes no IP rating for these. The Cuboid 8 is black, with white to special order.

All Cuboids are 8 ohm nominal. Optimal Audio pairs them with its Zone mixers, ZonePad wall controllers and WebApp, and quotes frequency response with its preset; see zone mixers and controllers compared.

Comparison table: 4″ to 8″ models

These are the sizes most bars, cafés, shops and gyms use. All figures are from the manufacturers’ datasheets.

Power is continuous for Biamp and AES for Martin Audio and Optimal Audio. Low-impedance figures are shown for the CT, TX and TX-WR models; for the 16 ohm MASK CT models the sensitivity shown is Biamp’s 1W figure (at 2.83V it is 85 dB for the 4CT and 87 dB for the 6CT). 70V taps also exist on every 100V model. “Not quoted” means the manufacturer gives no IP rating for that version; for the CDD6TX-WR, Martin Audio’s datasheet is not clear on whether a bracket is included, so ask us before ordering.

Three things stand out. The Cuboid 5 and 6 have by far the widest pattern, which suits low ceilings and close listeners. The MASK6C and 6CT, with 50° vertical, put more of their energy at a defined area and less on the floor and ceiling. The CDD models have the highest published sensitivity and maximum SPL at each size, allowing for the different test methods.

Larger models: 10″ to 15″

For bigger rooms, function suites and small stages, CDD and Cuboid both continue up the range. Apart’s MASK stops at 8″. If you are weighing these against a portable column, see column PA vs box speakers.

All six are 8 ohm, and their wall brackets and yokes are optional accessories. The CDD10, 12 and 15 also come as weatherised WR versions, such as the IP54 CDD12-WR. Suspension hardware and fixing points are matters for the installer and the manufacturer’s instructions, not this guide.

How to choose

Room size and throw

Small, low-ceilinged rooms with listeners close to the speakers favour wide coverage: Cuboid 3, 5 and 6, MASK4C, CDD5. Longer rooms where the back tables need level without blasting the front favour the CDD’s differential pattern or the narrower Cuboid 8 and MASK6C. As a rough guide, more small speakers spread evenly beat a few big ones turned up; the spacing maths is in install speakers: how many you need.

Music or speech

For paging and quiet background music, any of the 4″ to 6.5″ models will do the job and the 100V versions keep wiring simple. Where music is part of the offer, as in a bar, restaurant or gym, pick by low-frequency extension and headroom, and plan on a subwoofer. Biamp gives the MASK6C an operating range down to 65 Hz at -10 dB; Martin Audio puts the CDD6 at -10 dB at 70 Hz and the CDD8 at 55 Hz; Optimal Audio quotes the Cuboid 6 at -10 dB at 70 Hz with its preset.

100V line or low impedance

100V line suits many speakers on long runs with level set per speaker by tap. Low impedance suits a few higher-quality speakers near the amplifier, typically with a sub and DSP. The full explanation is in our commercial and background audio guide, and impedance loads are covered in matching amplifiers and speakers. Two points specific to these ranges:

• The tap limits maximum level. Martin Audio’s CDD5TX-WR datasheet gives 104 dB at 1m on the 25W tap, against 110 dB continuous on low impedance.
• Some models are low impedance only: MASK4C, MASK6C, MASK8F, standard CDD, the CDD8-WR, CDD10-WR and CDD12-WR, Cuboid 3, 5 and 6 without TX, and Cuboid 8 and above. Never connect these to a 100V output. The MASK CT models run at 16 ohms, not 8, when switched to low impedance.

Design, installation and testing of any electrical system, including 100V line audio, is a job for a competent person. We can help with product selection.

Indoors or out

Outdoors, choose a model the maker rates for it: MASK4C, 4CT, 6C or 6CT (IP64), any CDD WR or TX-WR model (IP54, for positions sheltered from direct exposure to the elements), or Cuboid 3, 5 and 6 with the terminal cover fitted (IP54). Check that brackets and accessories are rated too: Apart’s optional MASKC brackets are indoor only, while Martin Audio’s CDDCB ceiling brackets are sold as weatherised. For planning outdoor areas, see our guide to outdoor speakers for beer gardens and terraces.

Looks

All three ranges offer black or white in the small sizes. Martin Audio will finish any CDD in a RAL colour to order. The wooden Cuboid 10, 12 and 15 are finished in black textured paint.

Matching subwoofers from the same maker

Each manufacturer names its own subs for these speakers. We have listed only what the manufacturers say; placement and crossover principles are in our subwoofer guide.

Popular picks from the shop

Frequently asked questions

What is the difference between the Apart MASK6C and MASK6CT?

The MASK6CT adds a transformer and tap switch. It runs on a 100V line at 60, 30, 15 or 6W, on 70V, or at 16 ohms low impedance. The MASK6C is an 8 ohm speaker only. Drivers, coverage (100° x 50°), IP64 rating and the ClickMount bracket are the same.

Can Martin Audio CDD speakers run on 100V line?

Only the TX versions. The CDD5TX-WR taps at 25, 12.5 or 6W and the CDD6TX-WR at 50, 25 or 12.5W on 100V, and Martin Audio also makes CDD8TX and CDD10TX models. Standard CDD models and the plain WR models are 8 ohm only.

Are Optimal Audio Cuboid speakers waterproof?

The Cuboid 3, 5 and 6, including TX versions, are rated IP54 when used with the accessory terminal cover. Without it, Optimal Audio does not claim IP54. It quotes no IP rating for the Cuboid 8, 10, 12 and 15.

Which is louder, the Martin CDD6 or the Apart MASK6C?

On the datasheets the CDD6 gives 113 dB continuous and 119 dB peak at 1m, and the MASK6C 111 dB and 117 dB. Because the two makers measure differently, treat that as a small difference; the bigger practical difference is coverage pattern.

Do these speakers come with brackets?

The MASK4C, 4CT, 6C and 6CT come with the ClickMount bracket and a safety cable, the MASK2 with a turn/tilt bracket and the MASK8F with U-brackets. The CDD5 and CDD5TX-WR include a bracket; the CDD6, CDD8 and larger use optional brackets (ask us about the CDD6TX-WR, as Martin Audio’s datasheet is not clear). Cuboid 3, 5 and 6 include a wall bracket; Cuboid 8 and up do not.

Do I need a subwoofer with surface-mount speakers?

Not for paging or quiet background music. For music at any level, a sub from the same maker, with the satellites high-passed, usually sounds better than turning the small speakers up.