Boston Acoustics BA7500 Digital

Performance:

It is important to measure the performance of the system based on its specified uses and not out of context, ie. as a Desktop multimedia/theatre system, not a home theatre system. The system was built to include 4-channel gaming, Desktop theatre (Dolby Digial 5.1) audio, and music. Some reviews have completely missed the usage as a DD 5.1 system, and the inbuilt AC3 decoder, which eliminates the need for a seperate receiver or decoder. When considering the price of the system, the cost of factoring in a hardware decoder should be noted. If hardware DD decoding is not an issue, the US$100 cheaper BA4800 should provide similar performance for less cost – the BA7500 in fact uses the same subwoofer as the BA4800 and part of what you are paying for in the BA7500 is the aesthetics of the slim speaker design.
It is also notable that Boston Acoustics has declined to provide the system power output levels. Wattage does not always tell the quality/volume of the system, basically bigger is not always better. For example the Logitech DSR-100 system offers a 100-Watt system, but this is at a significant “up to” 10% THD (Total Harmonic Distortion). So instead of competing on a power output basis, Boston Acoustics has chosen to provide SPL (sound pressure level) outputs, which in the case of the BA7500 is at a significant 107dB. In a nutshell, “they are loud”. As noted further on in the review the speakers can produce an extremely loud output with no distortion.

Overall sound quality:
I was particularly impressed with the upper range of the speakers, considering they are without a separate tweeter. The high range instrumentals such as cymbals were easily audible with excellent clarity and quality.
The midrange was reasonable, but felt slightly lacking, and didn’t sound as rich as I would have prefered.
The bass and LFE channel is provided by a 6 ½ “ bandpass subwoofer" (A two-chamber cabinet - One sealed, one vented; which according to Boston Acoustics will “create a sharp roll-off above and below its operating range, minimizing the need for an electrical filter or crossover”). The subwoofer produced crisp, tight bass, which when turned up to the higher levels could produce pure boomy effects enough to get the walls vibrating.

When listening to the whole frequency spectrum blended together, the system could produce the full range with easily distinguishable bass – midrange – treble.  However the system seems to accentuate the upper-midrange frequencies, and excels at reproducing the vocals with incredible clarity and accuracy, but at very loud volumes may produce peaky, over-enhanced highs, which may start to sound harsh to the ears. Conversely, the lower-midrange seems slightly weak compared to the rest of the sound range. In addition, the system as a whole lacked cohesiveness at times between the LFE and satellites, most likely due to the slightly below par lower-midrange. At times the audio did not blend in seamlessly at the frequency around the crossover point, and could be distinguished as coming specifically from the satellites or the subwoofer.
Overall in summary what I noticed about the system was an astounding performance and detail, especially in the reproduction of the vocals. However, as mentioned earlier some lower-midrange sounds such as guitars were still audible and clear, but were slightly weak compared to the rest of the frequency range. The listed frequency response for this system is 45-20000hz, which will theoretically reproduce all but the lowest frequencies, including the double bassoon and a few organ notes.

Pushing the volume of the system up higher only made them sound better, and I only detected a trace of distortion at the very maximum volume setting, (which in all fairness, when used in a desktop setup will be enough to make you go deaf). The speakers also managed to keep their audio quality, without starting to sound hard or grainy at high volumes. The subwoofer did however start to fall behind the speakers at moderately high volumes – this is noting however that the room was noticeably shaking and the speakers can output a max SPL of 107db. When testing the system at high volumes I noticed some “rattling” noises, but upon further investigation found it out to be caused within the walls themselves rattling!

Speaker hiss when the speaker volume is turned up with no actual sound output can also be an issue. Either the amplifier or the sound card can cause this. With analog output some hiss could be heard from the speakers with the master volume past about 50%, but with digital output could go all the way up with only barely audible distortion. This would tend to suggest that the problem is to do with the sound card rather than the amplifier.

The speakers also sound like more of a non-directional sound system – this means the exact location of a sound is not easy for the listener to pinpoint. I feel this creates a more “immersive” overall feeling, which may be better for effects such as an object passing through you in certain DVD movies, but not so good where exact locations of a sound source is required, such as in a FPS game where the more accurate the ability to pinpoint source of an enemy the better. This is however a subjective topic and different people may hold different views.

  Onto the music, gaming, and DVD playback and conclusion: