ABIT SP50 Home Theater Speakers & AU10 Sound Card

SP50 Speaker System

The only discrepancy between the technical details and the actual product is that there was no G9 multipin connection on the subwoofer sent to us, despite it being described in the specifications.  Connections between the AU10 and the amplifier are via an adapter cable that goes from the G9 connection on the AU10 card to a fan of six RCA connections on the amplifier.           

Speaker Specifications

a. Continuous power
    (1) 40W x1 ref. Subwoofer driven only at 100 Hz @ 10% THD
    (2) 17W x 2 ref. 2 channels driven at 1KKz @ 10% THD.
    (3) 10W x 5 + 35 x 1 ref. All channels driven at 10% THD.

b. Channel separation: >60dB ref. 1KHz
c. Signal to Noise ratio: Subwoofer :>70dB @ 1W/A-wtd, Satellite:>70dB @ 1W/A-wtd.
d. Frequency response: Satellite 200Hz ~ 20KHz, Center 100Hz ~20KHz,
 Subwoofer 30Hz ~ 300Hz

e. THD: <1% for all channels

f. Power supply: 230V/50Hz, 120V/60Hz, 100V/50~60Hz

Physically, the subwoofer enclosure takes up a lot of floor space (206(W) x 380(H) x 510(D) mm), especially under a desk that may also be occupied by a minitower.  The egg shaped satellite speakers maintain a low profile, fitting into about the size of a fist.  In addition, the stylistic choice of a wood grained finish for the sub is slightly disappointing; however, the satellite speakers are a sleek black that fits in on a modern desktop, although the speaker cables do not match the look, as they are bright white.  The magnetic shielding in the satellites is fairly effective, though in close proximity to the monitor they did create some effects that indicate the shielding is not 100% effective.

Unfortunately, the output power section is not presented very effectively. 10% THD is an unreasonable level of quality to use when specifying a system, as no one should sacrifice that much quality in exchange for getting extra power.  The user manual also reports the speakers as being able to handle these sorts of powers in terms of RMS; however, the amplifier specifications do not indicate that it was measured with the same technique, producing some questions as to the actual output power of the system within an acceptable quality range.

The channel separation indicates that bleed-over between the left and right, or front and rear channels, will be audible only at higher volumes, such as when the maximum program level is greater than 60 dB above the noise floor of the room.  This is when the bleed-over could be heard above the room buzz, though it would be a whole lot quieter than the nominal program level.  This spec is measured at 1kHz; close listening actually indicates that there is more crosstalk at higher frequencies.  The signal to noise ratio is decent, though some noise it still evident at higher volumes.  It provides for a dynamic range of up to 70 dB before the noise floor becomes a problem.   This also minimizes the hiss when the system is not playing music but still turned up.  These speakers exhibited some hiss at high volumes when not playing audio, indicating that some noise will be present in the system.

Unfortunately, ABIT fails to indicate how accurately the speaker reproduces the frequencies across the given spectrum by indicating a tolerance.  Some unofficial frequency response diagrams indicate that the center channel speaker fits their specs fairly well, however, there is a large dip in middle of the vocal range that seems counterintuitive; after all, the primary job of the center speaker is to reproduce the vocal range.  With the sub’s specifications, the lack of a tolerance prevents the specifications from indicating the roll off that is present below 90 Hz, making this unit more of a bass module for extending the frequency response of the system than a true subwoofer that reinforces the lowest frequencies.

The individual <1% THD spec is a little confusing when looking back to the output power section, which was driven at 10% THD.  This specification seems to refer to the speakers’ acoustic nature, and possibly indicates that they introduce few harmonics into the sound.  If this is referring to the amplifier, it seems to contradict the output power section, leading to some distrust of both specifications.

The last item included in the package is the WinDVD 2000 remote control and included software.   There is an IR receiver that goes along with it, connecting inline to the keyboard connection of the computer.  This remote works on standard IR requirements, like line of sight for the receiver to work.