The tweeter is rather unusual. It has a 25mm soft dome at its centre, with an ‘over-sized’ long-throw surround that increases the diameter of the moving part to 40mm. All this is driven by a voice coil powered by a small neodymium magnet that’s equipped with a ‘crown-shaped’ heat-sink that not only dissipates heat from the magnet to reduce dynamic compression effects and increase power-handling capacity, but also acts as a back-chamber for the dome. The tweeter sits in a very shallow horn to increase its efficiency and control its directivity.

At the base of the front baffle is a very large, rectangular vent measuring 120×90mm. I couldn’t measure the depth of the port because my tape measure was impeded at a depth of 220mm by a silver metal mesh grille, presumably to prevent small pests (mice and suchlike) from making a home inside the speakers, nestled in the comfy fluffy white acoustic material, alongside the nice warm magnets! I often castigate manufacturers for not blocking off large vents in this way, so I was genuinely pleased that Atlantic Technology has done so.

Around the rear of the speakers is the speaker terminal plate, which sports ‘HF’ and ‘LF’ pairs of multi-way gold-plated speaker terminals, bridged by gold-plated buss bars. Above these is a small, three-position toggle switch, with the positions marked ‘+’, ‘0’ and ‘–’. As you’ve probably guessed, this switch allows you to alter the output of the tweeter relative to the bass/midrange drivers. The manual says: ‘This control changes the relative output level of the tweeter. It has been designed to hep compensate for different room acoustics and personal listening preferences. The ‘0’ position is the most “accurate” frequency response, but that does not mean that it is necessarily the “recommended” position.’

I was a little surprised to find that the serial numbers on the pair of speakers I was supplied for review were not contiguous, and that there were not one, but two serial numbers per speaker, the second set being on a hologram sticker. Steve Feinstein, Atlantic Technology’s Director of Marketing and Product Development, told me not to worry about the non-consecutive serial numbers, saying: ‘They are not matched pairs—our QC is good enough that they don’t have to be!’ He also told me that the hologram label was an internal tracking number for the number of H-PAS products Atlantic Technology had shipped and had no relevance to the end user. However, I also wondered whether it was a countermeasure against counterfeiting, given that Atlantic Technology’s website warns under the heading ‘Counterfeit Product Alert’: ‘We have reason to suspect that an internet storefront is listing counterfeit Atlantic Technology products for sale which purport to carry the Atlantic Technology logo and trademark. Counterfeit products are not built with genuine Atlantic Technology parts. They do not conform to our specifications or quality standards, and carry no warranty.’ The company then supplies a list of approved internet sites for sales of Atlantic Technology products, one of which, Outlaw Audio, has the exclusive internet sales agency for H-PAS products.