“ These are amazing. If you can get them for a low price, do so. They are a bit uncomfortable, so you might not want to use them for long periods of time. Their clarity is fantastic though, the bass while not being big in quantity is extremely accurate and with a decent amp (I'm using the 300 Ohm version of the headphones) it is just fantastic in quality. Despite being a closed headphone...” --FirsToStrike
From an old MB Quart brochure (circa late 80s): The Quart Phone 50 Dynamic, semi-open headphone. Coupling: circumaural. Frequency response: 10 Hz - 22 kHz. Nominal Impedance: 120 ohms (x2). Sound Pressure Level: 96 dB. Rated Power Handling: 0.1 watt. Distortion <0.5%. Weight (without cord): 245 grams.
Spark High Definition In-ear Headphones are the combination of precision acoustics, unique design and expert ergonomic research. Powerful and accurate acoustics are achieved through high performance dynamic driver and special high definition acoustic filter built-in, resulting in full, explosive bass, intense mid-range and clear treble frequency response that will put a smile on your face...