A buyer recently emailed us with the question of how big a room can a pair of M-8S be used in with good results. The answer was quite long, so I would like to share it with the rest of the community. If any of the following info sounds too confusing, raise your questions in this thread and I'll do my best to go into further detail.
This question has a complex answer because of so many different variables that can affect how well a pair of speakers work within a listening space. Here are some of these considerations and why they are relevant:
Intended Use - Demanding home theater applications require 105dB per channel of sound output, though most casual home theater use are done at around 10dB below reference level, meaning a 95dB maximum output. Even less demanding is typical background music system such as for a party/living room, with an average of 70-75dB, and peak output of 85-90dB.
Room Shape - Rooms in older homes tend to have low ceilings with well defined 4 walls and a door, which gives very predictable results in terms of how much room gain can be expected. Rooms in newer homes, however, have higher ceilings, and significant openings into other areas of the home, making it harder to estimate room gain.
Wall/Floor/Furniture Covering - Rooms with more reflective surfaces such as uncovered walls, windows, hardwood floors, will tend to generate more room gain than well covered rooms, but the resulting gain will cause an audible echo and degrade sound quality.
Listening Distance - Most home theater applications result in a 10-20 feet listening distance. Distance for a general living space may be much less well defined as listeners move about, but these applications are also much less demanding in terms of volume output.
Given the above considerations we can make the following analysis with regards to the suitability of the M-8S for various applications:
Demanding Home Theater - This application requires the ability to output 105dB peak per channel. The M-8S has a 90dB 1W/1M sensitivity, which when combined with a clean 100-watt per channel amplifier, will be able to provide 110dB of output at 1 meter, or 3 feet. After factoring in typical 6dB room gain for full range speakers, the M-8S will be able to produce 105dB of peak output at about 4 meters distance, or about 13 feet.
Typical Home Theater - For this application, we assume a 10dB below reference level setting, with peak output of 95dB. The M-8S will be able to produce this level of performance at up to 10 meters, or about 33 feet.
Background Music - We assume a 75dB average listening level with 90dB peaks for this application. The M-8S will be able to produce this output level at over 16 meters, or 53 feet.
Suffice to say, the M-8S is suitable for a wide range of applications and will not have difficulty providing adequate output levels for most residential spaces and rooms. Even under the most demanding home theater applications, the suggested listening distance of 13 feet is in-line with the average for even the largest TVs. For example, a 70" TV has a recommended viewing range of 9 to 15 feet.
