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REVIEW: HP ZR2440w Part 9


Backlight

The LED backlight of the HP ZR2440w is PWM-controlled. Luminance settings of less than 100 percent are achieved through temporary darkening of the LEDs. At 140 cd/m² at the desk, we measured a high switching frequency of 430 Hz. Because of the high maximum luminance, considerable reductions must be made; the duty cycle is just 43 percent. Nonetheless, even very sensitive people should not notice any backlight flickering at this high frequency.
The PWM frequency of the LED backlight is high.

Die PWM-Frequenz des LED-Backlights ist hoch.

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Sound

Like its predecessor, the HP ZR2440w does not have any integrated speakers, but it offers a digital audio output. This means that it is possible to feed the sound transmitted from external speakers via HDMI port digitally through to external speakers or a sound system.

DVD and Video

The HP ZR2440w has a HDMI port, which makes it multimedia enabled. Whilst the DVI or Display Port connection are usually used most often for playback via PC, external players such as Blu-ray players and games consoles can be connected with the HP ZR2440w via HDMI connection. The advantage of HDMI is that both the sound and picture can be transmitted; although a Display Port also offers this convenience, it is still rare.

Test of the video characteristics of the HP ZR2440w.

There is no special movie or cinema image mode; we recommend the "Standard (6500K)" image mode or the user-defined mode, provided that the contrast value is reduced to 67. The good contrast values help the monitor achieve first class image display, even for films. The even illumination ensures that even when black bands are displayed, no unpleasant bright patches appear at the edges or corners. Although the image construction of the HP ZR2440w does not break any records, fast-paced scenes are also displayed in sufficiently sharp quality.

Scaling, image rates and deinterlacing

As we already mentioned in the interpolation section, the HP ZR2440w offers various scaling options, including 1:1 display. For external playback via the HDMI port, the "Display overflow" option also becomes available. Unlike PC mode, all scaling options are available, regardless of what kind of scaling the player outputs. In the table below is a summary of which signals the HP ZR2440w can display correctly, i.e. without distorted or truncated display.

Signal Undistorted playback
SD (16:9 - anamorphic) No
SD (4:3) No
HD (720p) Yes (also pixel precise)
HD (1080p) Yes (also pixel precise)

Thus, DVD films in 16:9 widescreen format must always be upscaled by the player to 720p in order to ensure that they are displayed correctly on the HP ZR2440w. However, the ZR2440w cannot play back films in 4:3 image format at any setting on either the player or monitor.

As well as the 60 Hz that is standard for LCD screens, the HP ZR2440w also supports 50 Hz, which is important for the judder-free playback of DVD films. It is very pleasing that the HP ZR2440w is also capable of playing back a 1080p24 signal and can therefore also play back Blu-ray films without juddering thanks to it 24 Hz support.

The HP ZR2440w is able to play back half-frame based signals (480i, 576i, 1080i), but it depends on the signal cadence. The PAL signal with a cadence of 2:2 that is usual in Europe is not recognised correctly by the ZR2440w and the monitor upscales the half frames to the panel resolution only via simple field scaling. As a result, image quality is inevitably lost. However, the deinterlacer does recognise the NTSC 3:2 cadence signal that is widespread in America and Asia and it is transformed into full frames.

Supported colour models and signal level

For external playback via HDMI, the HP ZR2440w supports RGB and the YCbCr (4:2:2) and YCbCr (4:4:4) colour model. If material is played back in RGB, the HP ZR2440w expects PC levels and thus uses the full range of hues. The HP ZR2440w does not offer any HDMI black point setting such as Samsung monitors offer, but since the various colour models are recognised and processed correctly, we do not miss this option.

All colour models are supported.

The importance of the adjusted video levels in playback is often underestimated, but it is an important criterion in providing accurate display. If adjustment problems arise, this either results in a greatly reduced range of hues or a washed out, matte image without full black or white.

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