HSU VTF-3 MK2 (maximum extension)

[Ilkka]

Manufacturer: HSU Research
Model: VTF-3 MK2
Provided by: Takku
Manufacturer link: HSU Research : VTF-3 MK 2
Price: $699

Manufacturer specs:
• Frequency response (Maximum extension mode) ± 2 dB 18 Hz
• Frequency response (Maximum output mode) ± 2 dB 22 Hz
• Frequency response (Maximum extension mode) ± 1 dB 20 Hz
• Frequency response (Maximum output mode) ± 1 dB 25 Hz
• Woofer size 12 inches
• Amplifier power rating 350 Watts
• Crossover frequency range 30-90 Hz, bypassable
• Crossover slope 24 dB per octave
• Crossover type low pass only
• Phase 0/180°
• Dimensions 22"(h)/15"(w)/23"(d)
• Shipping weight 80 lbs.
• Finish Black, Maple, Rosewood
• Power Requirements 435 Watts
• Warranty 7 Years on the woofer, 2 years on Electronics

Configuration as tested:
Phase: 0 degrees
Tuning frequency: 20 Hz (one port plug)
Subsonic filter: 20 Hz (maximum extension mode)
Orientation: Sideways

[Ilkka]

+/- 3 dB points: 16 Hz - 140 Hz

[Ilkka]

[Ilkka]

Hsu vtf3 mk2 20 Hz
By plugging one of the ports one achieves around 4 Hz more extension. The shape of the frequency response is still quite good, although the same upper end roll off can be seen. Therefore I wouldn't use it with much higher crossover than 80 Hz. The built in crossover doesn't go higher than ~70 Hz. The lowest setting results in very low ~25 Hz crossover. The maximum mid bass output is lowered by at least 2-3 dB compared to maximum output mode. The deep bass compression goes even worse because now there is only a single 3” port left. THD profile is similar to the 25 Hz tune with high deep bass distortion at high output levels, and upper bass distortion anomalies/resonances. Group delay stay low down to 28 Hz, but grows rapidly below. Spectral decay shows a lot of ringing near the tuning frequency. Spectral contamination is similar to the 25 Hz tune, though with slightly higher overall distortion. The overall build quality is average.

+ Really good extension and relatively flat frequency response
+ High mid/upper bass output capability
+ Overall price/performance ratio

- Somewhat high deep bass distortion at high output levels
- Distortion anomalies/resonances in upper bass range
- Ringing around the tuning frequency

[vfrjim]

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