Axiom EP-600 (1st test)

[Ilkka]

Manufacturer: Axiom Audio
Model: EP-600
Provided by: Ilkka
Manufacturer link: Axiom Audio
Price: $1780

Manufacturer specs:
• Enclosure: Vortex / Reflex
• Max Amp Power: 600 Watts
• Cross-over Adjust: 40-100 Hz
• Phase: 0 & 180
• Woofer Size: 12”
• DSP Controlled: Yes
• Line In and Out: Yes
• Balanced Line In and Out: Yes
• High Level In: Yes
• Room Trim: Yes
• Dynamic Power Supply: Yes
• Boost Control: Yes
• Anechoic Resp. +/- 1.5dB: 19-100 Hz
• Anechoic Resp. +/- 3dB: 17-100 Hz
• Room Resp. + 3dB/- 9dB: 15-100 Hz
• Max SPL Anechoic: 111 dB
• Max SPL In Room: 122 dB
• Dimensions HWD mm: 1156 x 381 x 432
• Dimensions HWD inches: 45½ x 15 x 17
• Weight lbs each: 103.4 lbs
• Weight kg each: 46.901 kg

Configuration as tested:
Phase: 0 degrees
Low pass filter: Bypass
EQ/Room Trim: Flat
Front grill removed
Orientation: Horizontal

[Ilkka]

+/- 3 dB points: 18 Hz - 98 Hz

[Ilkka]

[Ilkka]

For THD data see 2nd test.

[Ilkka]

[Ilkka]

The frequency response is quite flat in 20-100 Hz range but is filtered steeply away above and below. The crossover can not be disabled which should be noted if any higher than 100 Hz crossover is required. Otherwise the crossover works as promised. The maximum output compresses heavily everywhere else than in 30-50 Hz range. It sort of reminds of a band pass subwoofer, but in fact is done by active DSP limiting. One could ask a little bit more output from such an expensive and also rather large subwoofer. Axiom’s output limiters work very efficiently and won’t allot any kind of strange noises out of the subwoofer. There is some “port chuffing” near the maximum output, but not much. There was some controversy regarding the distortion measurements so I decided to re-test it later in order to rule out any human error. Please see the 2nd test thread for additional info. The group delay stays low down to 40 Hz but grows rapidly below. It exceeds the 1 cycle limit at 29 Hz. The sudden and abrupt change in phase may be heard as slightly delayed lowest notes. As one could imagine by looking at the frequency response plot, there’s quite a lot of ringing around both steep slopes at 20 Hz and 100 Hz.

The Axiom EP-600 is sort of a strange bird. It’s obvious that a lot of engineering was poured into this subwoofer; it only seems that some aspects weren’t necessarily considered carefully enough. The amplifier is a very sturdy class D unit with a conventional analog power supply, and the woofer itself has a large 3” dual voice coil, so the basics are in order. The enclosure could be a little bit more rigid; now the panels are only 3/4" thick and the internal braces are spaced too far away from each other.

+ Relatively flat frequency response
+ High output in 30-50 Hz range
+ Good/inaudible output limiters (active DSP)
+ Small footprint when placed vertically

- High distortion at all frequencies
- High power compression
- High group delay and slow decay rate at low frequencies
- Somewhat weak enclosure