Product Review (March 2004) - Amphony
Model 2000 2.4GHz Digital Wireless Headphones

Wireless headphones have been around for some time with results that often times fall short of user's expectations. My last pair of wireless headphones used 900MHz analog technology and most of the time worked fairly well . However, the technology sometimes resulted in occasional static with dropouts, range problems and limited dynamics. New wireless headphone technology such as the Model 2000 offered by Amphony Corporation, uses digital transmission along with sophisticated digital error correction that results in superior performance. The Model 2000 is a very capable product that transmits audio to the headphones using the 2.4 GHz band. Digital data is sent at a rate in excess of 3 Mbps (million bits per second) resulting in true CD sound quality with no audio compression. A noise-shaping filter incorporated in the headphones is used to remove quantization noise from the audible frequency band. The headphones have velour ear cushions and are comfortable to wear.

Main Unit
The main unit is fairly small measuring only 7" wide and 5" deep. An AC adapter is included that provides 9VDC to the unit. The top of the chassis has indicators on the left side that let the user know what input is active. The corresponding digital input (optical or coaxial) is automatically selected when a valid data stream is detected. If no digital input is detected, the unit defaults to the analog inputs. The center knob is used to control the analog input level to the analog-to-digital converter (ADC) within the base unit. This is important in making sure the full range of the ADC is utilized which will result in the maximum signal-to-noise ratio. The top right indicators illuminate when valid data is being transmitted to the headphones and when the corresponding battery compartment is populated and charging. The Model 2000 includes two full pairs of AA NiMH rechargeable batteries so that one pair can be used in the headphones while the other pair is charging in the base unit. This ensures you'll always have a set of batteries ready to go. Each battery is rated at 1.2 volts at 1600 mAH and is said to last up to 100 hours per charge under normal use.

Interfaces
The Model 2000 is designed to interface to both analog and digital audio sources. The level control allows the user to set the optimal front-end gain to the analog-to-digital converter for analog sources. The goal is to maximize the audio level without clipping the signal. This will give the best signal-to-noise and dynamic range possible in the audio transfer to the headphones. Toslink as well as coaxial digital inputs are available. The digital inputs accept 32K, 44.1K or 48K sampling rates. The Data Out port is to be used with the optional RangeBooster Transmitter module which is said to improve reception. We didn't have one on hand so we could not verify this.

Performance
We connected the H2000 system to our Sony DVP-NS900V SACD/DVD players for testing. We used the analog and digital outputs of the player to drive the inputs on the base unit. We had to disconnect the digital inputs to force the H2000 to switch to the analog inputs.

The headphones are fairly light even with the batteries installed. Each side of the headphones hold a single AA battery that locks securely into place. The level control is conveniently placed on the right side of the ear piece and adjustable with your thumb. The headphones had adequate power and played loud enough for my taste.

Sound quality was very good for a wireless system in my opinion. In fact, I haven't heard a better wireless system that I can recall. However, it still has serious competition with wired headphones such as the inexpensive Grado (SR-60 and SR-80) line. Taking the cost of the system into account, the H2000 delivers great performance for the money.

We disconnected our 2.4 GHz spread spectrum phone to prevent any interference with the performance of the H2000. Amphony recommends that you consider the environment in which you use the H2000 wireless system as it may encounter interference with such products as 2.4 GHz wireless phones and wireless Internet devices. While the system worked perfectly in our test setup, we did find limitations in the range of the H2000 headphone system. Shortly after moving from our main listening room where the transmitter was located, we did encounter some dropouts in the form of scratches. Much depended on the exact location and head orientation, but it was cartainly there. With this in mind, I would recommend keeping the distance between the transmitter and headphones to a minimum.

Conclusion
We have not listened to a wireless headphone system to date that worked as well as the Amphony Model 2000. What we liked about this product is the consistent sound quality and the fact that it supports both analog and digital interfaces. The fidelity was as good as we've heard from a wireless system. In short, if you need the convenience of a wireless system, you can't go wrong with the Amphony H2000 system keeping the interference issue in mind.

- Kevin Nakano


Review System

Display:Sharp - 22" AQUOS LCD Display
Preamplifier/Processor:
Parasound AVC-2500U THX-Ultra DTS/DD Preamp/Processor
Amplification: Parasound HCA-2205AT THX-Ultra Five Channel Amplifier
Bass Management: Miller & Kreisel BMC Mini 5.1 Bass Management Controller
Front Speakers: Miller & Kreisel S-150THX (L+R) and S-150AC (Center) Speakers
Rear Speakers: Miller & Kreisel SS-250 TripoleŽ Surround Speakers
Subwoofer: Two Miller & Kreisel MX-350THX MkII THX-Ultra Push-pull Subwoofers
Room Treatments: Echo Buster panels and Bass Buster towers
Set-top Box: Mitsubishi HD-5000 Receiver
D-VHS VCR: JVC HM-DH30000U D-VHS High-Definition D-Theater VCR
DVD/CD/SACD Player: Sony DVP-NS900V DVD/CD/SACD Player
DVD Audio/Video Player: Kenwood Sovereign DV-5900M 400-Disc DVD Changer
Laserdisc Player: Pioneer CLD-D704 CD/VCD/LD Player
A/V Cables: Ultralink Platinum and Advanced Performance Series Cables
Video Generator: Sencore VP300 SDTV/HDTV Video Pattern Generator
Video Signal Analyzer: Sencore VSA794 NTSC Video Signal Analyzer
Color Analyzer: Sencore CP5000 Multi-Display Color Analyzer


Review - At a Glance

Amphony - Model 2000 2.4GHz Digital Wireless Headphones

Features:

  • Digital audio transmission at full CD quality
  • Extended headphone frequency response
  • Digital audio interfaces
  • Noise-shaping filter
  • High speed data port for use with other Amphony products
  • Rechareable NiMH batteries included with charger built into base unit

    Transmitter Specifications:
    Audio Transmission Method:

    Digital (PCM sampled data)

    Transmitter Frequency: 2.4 GHz
    Signal-to-Noise Ratio (A-weighed): typical 100 dB (using digital interfaces)
    Dynamic Range: typical 100 dB (using digital interfaces)
    Channel Separation: typical 100 dB (using digital interfaces)
    Harmonic Distortion: typical -90 dB (using digital interfaces)
    Error Correction: 1/2 rate FEC
    Audio Sampling Method: 64 times oversampling
    Transmitted Data Rate: >3 Mbps

    Headphone Specifications:
    Type:

    Dynamic, Closed

    Operating Time: 100 hours with 2 AA batteries
    Frequency Response : 10 Hz - 24 kHz
    Maximum Sound Pressure Level: 120 dB

    Optional RangeBooster Transmitter Module Specifications:
    Max Transmitter Output Power:

    1 mW

    Transmitter Operating Range: 200 feet line-of-sight, 50 feet through walls/ceilings

    Includes:

  • 2.4GHz Digital Wireless Headphones
  • 2.4GHz Digital Audio Transmitter
  • AC Adapter (9VDC, 400mA)
  • Two-channel RCA cables
  • Four NiMH Rechargeable Batteries (Two on charger, two in headphones)

  • Company Information
    Amphony Corporation

    Source: Manufacture supplied
    Model Number: Model 2000
    MSRP: $249

    Warranty: 1 year parts / 90-day labor

    H2000 Data Sheet
    H2000 Product Manual

    URL: www.amphony.com

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