Sealed

All Arendal Sound 1961 speaker enclosures are designed for optimal sound quality and are based on sealed low-Q designs that provide excellent transient response. A low-Q design means that the low frequency performance is accurately damped, which delivers a tight sound without any boominess. The roll-off occurs at a natural sealed box rate of 12dB/octave below the resonance frequency of the speaker. This frequency (quoted as the -3dB point for the bass extension) is somewhat higher than that of a vented alignment. So, although sealed alignments may look less impressive on paper compared to vented alignments, you may be surprised at how deep they actually still go in-room.

It is worth bearing in mind that smaller rooms or speaker positions closer to a wall tend to add 6–12dB of extra gain per octave with descending frequency below about 40Hz. This dovetails nicely with the natural opposite delivered by the sealed alignment and results in a surprisingly extended and naturally flat in-room response.

Sealed boxes exhibit excellent, accurate sound reproduction, with a fast transient response and well damped impulse response. Their naturally flat in-room response and lack of ports deliver minimal phase shifts, making them the easiest to integrate with a powered subwoofer.

Vented

1961 Tower offer the possibility of being used in alternatively in a vented or sealed alignment. By removing the foam plug inside the slot port, the low frequency -3dB point (at a slope of 24dB/octave) can be extended and given different bass characteristics. The damping and therefore the impulse response are slightly less optimal than with the sealed alignment, so the bass gains a slightly ‘fatter’ and warmer quality, with the extended response obviously delivering more bass output down to the tuning frequency of the port.

Larger rooms and/or speaker positions further from room boundaries may appreciate this extra natural output because they are less supported than in a smaller room. Similarly, some listeners may enjoy this extra output in smaller rooms to deliver truly earth-shattering (though not entirely accurate!) bass.