Short answer: the Optimal Audio Cuboid 5, though neither ranks well in its class. It ranks #28 of 33 line array and installation pa speakers by sound quality, rated 2.5/5, at $110. The Optimal Audio Cuboid 3 ranks #31, rated 2.3/5, at $85, $25 cheaper, which does not close the gap in sound quality. Both are rated below 3.0/5 among the 33 line array and installation pa speakers, so if sound quality matters, look higher up that list instead.
What the Optimal Audio Cuboid 5 does well: A compact installation speaker from Optimal Audio with a 5” coaxial driver. The catch: Bass is very limited, so it needs a subwoofer, and the on-axis response is uneven (1.15 average deviation).
What the Optimal Audio Cuboid 3 does well: A tiny installation speaker from Optimal Audio with a 3” driver. Watch for: Bass is very limited, so it needs a subwoofer, and the on-axis response is very uneven (2.07 average deviation).
Buy the Optimal Audio Cuboid 5. It is rated higher for sound quality, and the $25 you would save on the Optimal Audio Cuboid 3 does not close the gap.
Want more options? Browse the full PA & Live Sound rankings.
Specifications Side By Side
| Optimal Audio Cuboid 5 | Optimal Audio Cuboid 3 | |
|---|---|---|
| Price | $110 each | $85 each |
| Ranked | #28 of 33 in Line Array and Installation PA Speakers | #31 of 33 in Line Array and Installation PA Speakers |
| Bluetooth | No | No |
| Drivers | 5” coaxial driver | 3” driver |
| Bass Extension (-3dB) | 122.0Hz (measured, manufacturer data via spinorama.org) | 115.0Hz (measured, manufacturer data via spinorama.org) |
| Bass Extension (-10dB) | about 91.5Hz (measured, manufacturer data via spinorama.org) | about 82.4Hz (measured, manufacturer data via spinorama.org) |
| Spinorama Preference Score | 0.27 | -0.18 |
| Spinorama Preference Score with Perfect Sub | 3.94 | 3.43 |
| DIY Kit | No | No |
Related Speaker Comparisons
How Optimal Audio Cuboid 5 compares with other leading options:
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- JBL CBT 70J-1 vs Coda Audio CoRay4
- Alcons Audio QRP40 vs Coda Audio CoRay4
- Alcons Audio QRP20 vs Coda Audio CoRay4
Prices on this page were last checked October 7, 2026 at 9:25 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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The Two Speakers In Full
Optimal Audio Cuboid 5: $110 each eBay
Same family: the Optimal Audio Cuboid 3 (smaller model, ranked lower, rated 2.3/5).
Pros: A compact installation speaker from Optimal Audio with a 5” coaxial driver. Optimal Audio’s measurements show a preference score of 0.27 that reaches 3.94 with an ideal subwoofer, with 0.74 listening window deviation.
Cons: Bass is very limited, so it needs a subwoofer, and the on-axis response is uneven (1.15 average deviation). That data is low quality and comes from Optimal Audio. Bass reaches 122.0Hz (-3dB) and about 92Hz (-10dB). That data is low quality.
Full Optimal Audio Cuboid 5 review and specifications →
| Bass Extension (-10dB) | about 91.5Hz (measured, manufacturer data via spinorama.org) |
|---|---|
| Bass Extension (-3dB) | 122.0Hz (measured, manufacturer data via spinorama.org) |
| Bluetooth | No |
| DIY Kit | No |
| Drivers | 5” coaxial driver |
| Spinorama Preference Score | 0.27 |
| Spinorama Preference Score with Perfect Sub | 3.94 |
- Reviews, Comparisons and Sound Samples
Optimal Audio Cuboid 3: $85 each eBay
Same family: the Optimal Audio Cuboid 5 (larger model, ranked higher, rated 2.5/5).
Pros: A tiny installation speaker from Optimal Audio with a 3” driver. Optimal Audio’s measurements show a preference score of -0.18 that reaches 3.43 with an ideal subwoofer, with 0.82 listening window deviation.
Cons: Bass is very limited, so it needs a subwoofer, and the on-axis response is very uneven (2.07 average deviation). That data is low quality and comes from Optimal Audio. Bass reaches 115.0Hz (-3dB) and about 82Hz (-10dB). That data is low quality.
Full Optimal Audio Cuboid 3 review and specifications →
| Bass Extension (-10dB) | about 82.4Hz (measured, manufacturer data via spinorama.org) |
|---|---|
| Bass Extension (-3dB) | 115.0Hz (measured, manufacturer data via spinorama.org) |
| Bluetooth | No |
| DIY Kit | No |
| Drivers | 3” driver |
| Spinorama Preference Score | -0.18 |
| Spinorama Preference Score with Perfect Sub | 3.43 |
- Reviews, Comparisons and Sound Samples