NHT 2.5i review part 3

 

Part 3 of the NHT 2.5i review contains frequency and impedance measurements of the individual loudspeaker driver’s mounted in the NHT 2.5i enclosure.

Tweeter:

 

Frequency:

Frequency measurement conditions:

Mic position: 1m distance, on mid-woofer-axis.
Smoothing: 1/24 octave smoothing applied.

Freq - H858 0deg 1L vs 2RFreq - H858 15deg 1L vs 2R

(click on picture to zoom)

Left:  Frequency response on-axis.
Right: Frequency response 15deg off-axis.
Blue = Left loudspeaker.
Red  = Right loudspeaker.

Freq - H858 0-15-21degFreq - H858 30-45-60deg

(click on picture to zoom)

Left:  Frequency response on-axis, 15 and 21deg off-axis.
Right: Frequency response 30, 45 and 60deg off-axis.

A smooth and linear tweeter frequency response. The aluminium dome break-up at 26kHz is well suppressed by the diffusor.

Impedance:

Imp - SEAS H858_25TAF-D 1L vs 2R Box

Blue: Left loudspeaker.
Green: Right loudspeaker.

Mid-woofer:

 

Frequency:

Frequency measurement conditions:

Mic position: 1m distance, on mid-woofer-axis.
Smoothing: 1/24 octave smoothing applied.

Freq - 830301 0deg 1L vs 2RFreq - 830301 15deg 1L vs 2R

(click on picture to zoom)

Left:  Frequency response on-axis.
Right: Frequency response 15deg off-axis.
Blue = Left loudspeaker.
Red  = Right loudspeaker.

Freq - 830301 0-15-21degFreq - 830301 30-45-60deg

(click on picture to zoom)

Left:  Frequency response on-axis, 15 and 21deg off-axis.
Right: Frequency response 30, 45 and 60deg off-axis.

The Peerless mid-woofer has a smooth and extended frequency response without any violent cone break-ups.

Impedance:

Imp - 830301 1L vs 2R Box

Blue: Left loudspeaker.
Green: Right loudspeaker.

The closed box resonance @ 93Hz

Sub-woofer:

 

Frequency measurement conditions:

Mic position: Nearfield. With and without cross-over.
Smoothing: 1/24 octave smoothing applied.

Freq - 830302-1L nearfield sw+port no x-overFreq - 830302-1L nearfield sw+port x-over

(click on picture to zoom)

Left:  Nearfield frequency response without x-over.
Right: Nearfield frequency response with x-over.
Blue = Sub-woofer.
Red  = Port.
Green = Sum port+sub-woofer.

The cross-over gives a 3.5dB boost @ 75Hz.

Impedance:

Imp - 830302 1L vs 2R BoxImp - 830302 1L vs 2R Box + x-over

(click on picture to zoom)

Left:  Impedance without x-over.
Right: Impedance with x-over.
Blue: Left loudspeaker.
Green: Right loudspeaker.

Box tuning frequency @ 33Hz without x-over and 30Hz with x-over.

Go to NHT 2.5i review part 4