DIY Infinity Kappa Perfect 12

[Ilkka]

Manufacturer: DIY
Provided by: Torkkis
Manufacturer link: -
Price: ~950 EUR

Manufacturer specs:
• Enclosure: Sealed, 50 litres, 35 mm real birch, e-mail to enclosure maker: veikko.suihkonen@cubico.fi, pictures
• Amplifier: NAD 214 (~300 W into 8 Ohm, bridged)
• DIY external crossover/EQ: 30-70 Hz 24 dB/oct, +0-9 dB @ 18 Hz

Configuration as tested:
Orientation: Standard down-firing
Crossover: Bypassed
EQ: No

[Ilkka]

+/- 3 dB points: 29 Hz - >200 Hz

[Ilkka]

[Ilkka]

The built quality of this DIY sub is very high. The enclosure didn't resonate at all even at highest levels. It features an external NAD power amp and a DIY crossover/EQ unit. The driver used was an Infinity Kappa Perfect 12". The sub has a quite optimum sealed sub frequency response. The slope starts at 50 Hz and descends at a rate less than 10 dB/oct., which tells that the final Q of the system is really low. In-room frequency response should be pretty flat down to single digits due to room gain. It does fairly well regarding max SPL when noticing that the Kappa Perfect isn't the most robust driver one can get these days. THD goes pretty high at lower frequencies and at higher output levels though. Regarding group delay and spectral decay this sub is among the very best I've ever measured. Spectral contamination test shows average maximum output capability with higher than average overall distortion. Multiples of these would be quite a performer even at high output levels.

+ Good frequency response for a smaller room
+ Low distortion up to medium output levels
+ Extremely low group delay and short decay time

- Medium maximum output capability
- High deep bass distortion

[Ayreonaut]

This sub measures lightning fast, there's no ringing at all!
The distortion above 40 Hz is less than 5% at a flat 102 dB!
I bet this sub would be incredible for music.

Nice job, Torkkis.

[Ilkka]

Ayreonaut wrote:

This sub measures lightning fast, there's no ringing at all!
The distortion above 40 Hz is less than 5% at a flat 102 dB!
I bet this sub would be incredible for music.

Nice job, Torkkis.

That's correct. This subs performs really well as long as you stay below 95-100 dB levels. Above that the THD goes pretty high at lower frequencies. Multiples of this would be a really great performer also for bigger places and higher listening levels.