HOQS Paraflex Speakers

What is Paraflex?

The Paraflex family of speakers are a new range of cabinet designs, based upon the compound quarter-wave resonator principle. This concept of acoustic loading was first shared with the public via the HOQWS Facebook group (also known as HOQS ) and is now gaining global renown. There are over 50 free to use Paraflex designs available on the Facebook group.

CAL has condensed the list down to around 10 key designs that are capable of covering the vast majority of sound reinforcement applications.

With extensive knowledge from working in the live sound reinforcement industry, these HOQS fundamental acoustic concepts have been further developed with all the necessary ergonomic and ease of use functionality to make the product range truly 'touring ready'. 

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Open Source & Community Support

CAL goes one step further than other manufacturers, offering extensive technical support to the global open source audio community.

We have multiple pages of free resources on this website, including the only place on the entire internet that contains an (almost) exhaustive list of all Paraflex designs, with links to all the plans, along with supporting specifications.

We offer the DIY community the resources they need to build cabinets themselves, including an ever growing range of hardware in our webshop.

Need help with Paraflex designs? Drop us a message, we'd love to help.

Global Leaders in Manufacturing

Here at CAL, we've built more Paraflex cabients than just about anyone else globally. We know these designs inside out, we know how to make them well and we know how to make them efficiently. Because of our expertise in manufacturing we are able to offer you high quality kits, unloaded cabs or plug and play ready solutions at great prices.

Global shipping is available for all our products.

  • Subwoofers

    C-2A GF 1x21"
    C-2E SF 1x21"
    C-2E.3 1x18"
    C-2E GF 2x15"
    Type C 1x18"

  • Midbass / Kicks

    C-2D 1x18"
    C-2D 1x15"

  • Midtops (horizontally arrayable)


  • Midtops (vertically arrayable)


  • Accessories


    'Phase plugs'




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So what should you pick?


If you want a large format subwoofer with excellent LF extension and high SPL output for a single 21" driver, you want the C-2A 1x21". Be warned, this cab is very large!

Do you need a medium format subwoofer with excellent LF extension and high SPL output capabilities? You need the C-2E SF 1x21". (This is currently my most popular subwoofer)

For the tightest of tight, punchy bass that sacrifices some LF extension for better transient response and power density, you need the C-2E 2x15".

For tight sounding bass with decent LF extension and good SPL output without the cost or size associated with a 21" sub, consider the C-2E.3 1x18".

Do you need a smaller format box that still performs well for the size? The classic Type C 1x18" is for you.


Do you require serious kick frequencies in a small format box? The C-2D 1x18" is my suggestion. (This is currently my most popular kick)

Require good, solid kick but want to use a 15" driver? The C-2D 1x15" is what you need.


If you need exceptional fidelity, good pattern control, high SPL and vertical stacking, you need the PF212 2x12". I sell 4 versions of this to cater for different uses and budgets. The CX1 variant has a single coaxial compression driver, the CX2 has dual compression drivers. (This is currently my most popular midtop)

If you want the same sort of quality as the above, but with a reduced footprint, cost and lower SPL, consider the PF 112CX 1x12". The CX stands for coaxial - the HF horn is mounted in the mouth of this box.

Are you after a more classic looking midtop, reminiscent of Rog's MT121/112? You want the PF112MT 1x12". A single 12" on Paraflex loading, with the HF horn mounted above.