More Information On The Sleepsonic® Stereo Speaker Pillow                               Read Reviews | FAQs

Brief Notes on Sleepsonic® Audio Components and Definitions of Their Specs:

• Dynamic Digital Stereo Headphones: This type can be very efficient and is easily powered from a 3.5mm headphone jack on a CD/tape player, PC, MP3 or any type of stereo equipment. Dynamic stereo headphones are typically used in recording studios.
• In most cases, the normal human hearing range is between 20Hz to approx 13.5KHz .
• Sleepsonic® Hi-Fi High Fidelity speakerphones mean delivery of frequency range is between 20-20KHz
• Power from a stereo player sold separately or provided by user (line output) is typically around 4.8 ohms
• Related to the durability issue is power-handling. A few milliwatts are enough to drive headphones to high volume, but audio engineers and performers tend to push the power limits and risk destroying them. Consumer headphones are generally rated to handle 100mW or less. Professional headphone models range from 100mW up to 1000mW (1W). Sleepsonic® is rated at 200 mW.
• Distortion: How accurately the headphones reproduce sounds and given in a percentage of signal distorted. Lower is better - 1% distortion or less (at maximum power). Tests have shown that 1% distortion is at the threshold of audibility. Headphones have less distortion at loud levels than speakers.
• Frequency Response: 20Hz to 20KHz (carrier wave) measured in hz or cycles per second.
  The frequency response will influence the alt and bass of the headphones. The 10Hz to 22k Hz is the ideal range. But it is very hard to make it to this range in the audio area. In general, it is 20Hz ~20k Hz.
• Impedance: 64 ohms
  The impedance will influence the power. In the same situation, when the impedance is higher, the power is smaller. This design requires less power to resist flow of electricity.
• Impedance - A measure of headphone load on an amplifier and stated in ohms. This factor is less important with solid state amplifiers, which can drive most headphone impedances, but can be significant with tube amplifiers, which are more sensitive to load impedances. Both consumer and professional headphones generally have impedances of less than 100 ohms. There are professional models rated at 200 ohms or more to minimize loading effects on distribution amplifiers which often drive a whole bank of headphones at one time. Be aware that very high impedance phones may require more power on the order of Watts instead of milliWatts.
• Sound Pressure level: 103 dB. SPL is also a sensitivity index. In general when SPL is higher, the headphones are better (how loud speakers can go without distortion).
• Sensitivity (loudness)- A measure of headphone efficiency in dBs SPL per milliwatt of input. A low number means that the headphones need more power to sound as loud as those which have a higher sensitivity. Headphones for portables need to be fairly sensitive because of the lower power output of portable stereos. Modern dynamic headphones have sensitivity ratings of 90 dB or more. When evaluating portable headphones or speaker pillows, look for a sensitivity rating of 100 dB or greater.
• Cable (with volume control): 3,6,or 9 foot detachable, or 12 foot fixed.
  Common Question: does the longer cable affect the sound quality?
  Answer: The longer cable will influence the sound a little bit, depending on the amplification source.