MB Quart has been in the audio business for nearly 30 years. During this time, the company has earned an outstanding reputation in car audio, which probably has something to do with the number of MB drivers that have been used in winning IASCA cars. MB is a German company and the name in German means "microphone builder." Founded in the early '70s to build precision microphones, the company branched out from that type of "transducer" to OEM loudspeaker manufacturing in the mid '70s and soon became known for its outstanding titanium tweeters (Avalon Acoustics uses an MB titanium dome in its $71,000 reference home audio speaker system). In 1988 the company established MB Quart USA to distribute both home and car audio products and, as they say, the rest is history (for more on MB Quart, visit www.mbquart.com).
This month's speaker review is the MB Quart Q-line three-way component system, which consists of the QSD 210 two-way system and the QSD 164 add-on midbass kit. This combination is very tricky in that you can purchase a two-way component system and then later convert to a three-way system with the addition of the QSD 164 midbass kit. At least, this is the intention with other two-ways in the series, such as the QSD 213, which uses a 5.25" woofer, and the QSD 216, which has a 6.5" woofer. In the system discussed this month, the QSD 210 actually uses a 4" woofer and MB really did not intend for the QSD 210 to be used stand-alone as a two-way system. This is nothing against MB, it's just that you really can't get much volume out of anybody's 4" woofer operating full-range. All this being said, the QSD 210/QSD 164 combination is really intended to be a three-way component system.
Included in the QSD 210 system is the QTD 25 1" (25mm) Q Series titanium dome neodymium tweeter, the QWD 100 4" (100mm) neo midrange, and the QXD 210 BTT (Balanced Temperature Technology) crossover. The QTD 25 is the latest in a long series of titanium neo domes for MB. This one consists of a 1" titanium dome that uses a cast aluminum body to help with heat dissipation. Heat is a big enemy for neo motor tweeters because they lack the physical mass that ferrite motors have with their large ferrite ring magnets, two steel plates, and large diameter steel pole pieces. Anything you can do to help heat dissipate from a neo tweeter is a big plus as it tends to loose its magnetic charge at ultra-high operating temperatures. However, MB's aluminum body, with the small heat sink fins around its perimeter, should take care of this problem quite well.
Like most metal domes, the QTD 25 uses a multi-spoke phase plug to correct the high frequency response and make it more flat. This plastic phase plug also works handily to keep your younger brother or kid from pushing the dome in with his fingers (this seems to be a near universal human trait - walk into any audio store and check out all the tweeter domes and I'd bet money you'll find at least one pushed in). The QTD 25 also uses magnetic fluid in the gap to increase power handling by wicking heat away from the voice coil. This also tends to dampen the tweeter's 1430Hz resonance peak. For mounting, Quart provides a stealth (the tweeter without mounting hardware for custom installation), flush mount, one-inch-high surface mount, and an angled mount that tilts the tweeter about eight degrees.