I'm an audio professional, so you can take this to the bank: When I was looking for new headset/intercom gear for a homebuilt, I did some browsing. I didn't browse ALL intercoms or "black-box" adaptor/interfaces, but several. None of them had frequency responce below 200-300 Hz. That's not even the bottom of the vocal range, let alone the bass range. If you care to have real sound, you need range from 60 Hz to about 8-10 kilohertz. Yes, home hi-fi goes higher (20 kHz), but 8-10 will do in an aircraft cabin. A big problem here is that very few manufactures of these aircraft products are publishing their frquency range. I went to the trouble of calling the back-room techs at some of these and learned that what's true elsewhere in the audio industry is true here: If they haven't printed the specs it's because their specs suck. Also, some of these replies mention low-volume problems when going thru the intercom. This is a common problem. There may be a couple of boxes out there that get to business, and the impedance-matching problem is also true SOMETIMES. Before going to that trouble (preamp or imp. match), find out if your end result will have full frequency range. And auto-muting. Now to the bottom line from my experince: I bought Lightspeed ANR's (Twenty 3G, and they have other models) and I'm extremely pleased. Not only full bass, but plenty of volume, active noise rediction, auto muting (really auto-ducking-- the music or cell phone volume ducks under an incoming/outgoing transmission), and bass-boost, treble-boost, or both to customize the tone. Comes with cables for iPod/CD and cell phone. The only drawback is as mentioned elsewhere, the music is only in your headset, not passenger. Depending on their taste in music, could be a blessing. Half the cost of Bose X.
Hi Russell. I run Vx Aviation, manufacturer of the ASX-2A/2B music adaptor/cell phone adapter cited previously. I call your attention to the specifications of these devices (for example http://vx-aviation.com/documents/ASX-2A_install.pdf). They are specified as 40Hz to 15KHz (-3db equivalent to + or - 1.5 dB) into 300 ohms. The music gain is nominally 14 dBV and the comms gain is 6 dBV allowing for a lot of installation flexibility, including driving multiple headsets. Output impedance is 75 ohms, so a load of 4 stereo headsets would be easily handled.
These units were designed for audiophiles who appreciate quality music and should be used with good quality headphones to get the full enjoyment. Automute is provided (selectable).
The only downside is that these devices are designed for permanent installation. It is possible to wire up cables to provide inline headphone jacks, 12V power and a 3.5mm audio cable, but we do not provide this. In addition, the ASX-2B version provides a cell phone interface that requires microphone cables, custom wired jacks and an ``answer switch`if required. Due to the vast variability in cell-phone jack pinouts and the ability of many cellphones to provide music as well, this wiring must be determined at installation.
For students of industrial design, the entire device is encapsulated in a 25pin D-Sub backshell and takes no panel space. It can even be tie wrapped to a wiring harness or other hardpoint, thus no physical modifications are required to the airframe (other than any switches required).
Please note that in some jurisdictions, the operation of a cell phone in flight is prohibited. Even when not, most cell phone towers do not direct energy more than a few hundred feet above ground level, so communications is unreliable. The use of a cell phone in an aircraft is best reserved for preflight or postflight communications.