Very simple. You and up to three other friends want to listen to the same mix under headphones. Just take the HC 4S, plug in, turn on, adjust your individual volumes, and groove.
The HC 4S provides master stereo Inputs which can be used to drive the four stereo headphone amplifiers. A Mono switch is provided on the front panel to drive both channels of all four amplifiers from a common mono source. Both 1/4" and 3.5mm jacks are on the front panel for adapter-free enjoyment.
The HC 4S is capable of delivering up to 200 milliwatts into headphones with rated impedances between 32-600 Ω. The precise amount of power depends on the exact impedance of the headphone in use and the number of headphones connected to the unit. Under most conditions, the HC 4S produces sound pressure levels in excess of 120 dB. This level is more than adequate for most listeners.
Two balanced Inputs provide a master stereo signal to four stereo headphone amplifiers, with individual stereo Level controls and Overload indicators. The Master Level control allows adjustment of the main stereo Input level for proper matching to any source. In addition, a Stereo/Mono switch converts the stereo Inputs to mono operation when required.
The HC 4S makes a valuable tool for any band wanting to practice anywhere, anytime, at any volume, without disturbing a soul. By connecting the HC 4S directly to the mixer outputs and using headphones instead of amps and speakers, the entire band can perform at ear shattering levels, with no feedback, with amazingly cleaner, clearer sound. The HC 4S is a very cost-effective alternative to renting a practice studio for every rehearsal.
Note: headphones with an impedance of less than 32 ohms are not recommended for use with the HC 6S.
Much confusion abounds regarding headphone power requirements. This note is intended to disperse some of the mist surrounding headphone specifications and hopefully give you a clearer understanding of how much power is really needed for your application.
Headphone manufacturers specify a sensitivity rating for their products that is very similar to loudspeaker sensitivity ratings. For loudspeakers, the standard is to apply 1 watt and then measure the sound pressure level (SPL) at a distance of 1 meter. For headphones, the standard is to apply 1 milliwatt (1 mW = 1/1000 of a watt) and then measure the sound pressure level at the earpiece (using a dummy head with built-in microphones). Sensitivity is then stated as the number of dB of actual sound level (SPL) produced by the headphones with 1 mW of input; headphone specifications commonly refer to this by the misleading term dB/mW. What they really mean is dB SPL for 1 mW input.
Think about these sensitivity definitions a moment: headphone sensitivity is rated using 1/1000 of a watt; loudspeaker sensitivity is rated using 1 watt. So a quick rule-of-thumb is that you are going to need about 1/1000 as much power to drive your headphones as to drive your loudspeakers since both of their sensitivity ratings are similar (around 90-110 dB-SPL). For example, if your hi-fi amp is rated at 65 watts, then you would need only 65 mW to drive comparable headphones. (Actually you need less than 65 mW since most people don't listen to their loudspeakers at 1 meter.) And this is exactly what you find in hi-fi receivers. Their headphone jacks typically provide only 10-20 mW of output Power.
Take another moment and think about all those portable MP3 players. Ever hear one? They sound great, and loud. Why you can even hear the headphones ten feet away as the teenage skateboarder that ran over your foot escapes.
Power output? About 12 mW.
If the above doesn't answer your question, or it's urgent...
Phone 425-355-6000, 8 AM to 5 PM PST, Monday through Friday.
If it's less urgent, you can email the factory.
For local service within the USA, find a service center.
HC 4S Headphone Amplifier Data Sheet
RaneNote: "Sound System Interconnection"
HC 4S Amplifier front DWG