Bluetooth Headset and Car Kit Reviews

Plantronics Discovery 640

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Review posted Dec. 2005 by Tong Zhang, Senior Editor

Check out our review of the newer Plantronics Discovery 655

Last summer, we reviewed Plantronics third generation M3500 Bluetooth headset which leverages Plantronics' Audio IQ technology and an integrated Digital Signal Processor (DSP) to enhance the audio clarity in noisy environments. The voice quality was so good on the M3500 that we gave it our Editor's Choice award. The only thing seemed to have slipped Plantronics' mind with that headset was in the style department. The 27-gram M3500 felt heavy and looked large on anybody's ear. But come this year, Plantronics released a new generation of Bluetooth headsets that cut down on weight and size, but increased style and usability. Among them, the Plantronics Discovery 640 Bluetooth headset leads the pack with a very lightweight, comfortable to wear design and great sound quality you've come to expect from a Plantronics product.

Some headsets are good looking; the Plantronics Discovery 640 took it one step up. The Discovery 640 is just over 2 inches long, weights only 9 grams. The design is simple yet sleek. The top of the headset slopes down at an angle and is capped by a multi-function button that can turn on and off the headset, put the headset in pairing mode among other functions. You will find an LED surrounding the multi-function button. The front of the headset has a long volume up and down rocker. The button is integrated into the body of the headset and is easy to push when the headset is in your ear. The Plantronics headset has an in-ear style design and comes with three soft gel ear tips in different sizes. The ear tip stays in your ear very securely thanks to the ear tip design and the light weight of the headset, and the soft gel makes it comfortable when wearing the headset for a long period of time. You will find the mic at the bottom of the headset and a small charging connector on the back of the headset.

The style of the Plantronics Discovery 640 didn't stop at the headset. Along with the Discovery 640, you will get a kit that includes a carrying pocket which also acts like a charging dock. It can be connected to either the included A/C adapter for charging, or the included AAA battery charging chamber that charges your headset using an included AAA battery. When you just need to carry the headset around, the carry pocket has a clip for your shirt pocket or a neck strap. The Plantronics offers yet a third option for charging the headset: if you don't want to carry the A/C charger, the Discovery 640 includes four charging adapters that allow you to charge the headset using your phone's A/C charger, provided your phone is a Nokia, Motorola, Sony Ericsson or Siemens. Very clever idea! The Plantronics package also includes ear gel tips in three sizes and an optional ear hook in case you need additional stabilizer for the headset which we have not had the need to use. All the items in the package are neatly stored in an attractive metal hard case with soft lining inside. Makes for a great gift item. On the bottom of the case, you will find a small mirror which comes in handy when you are putting on the headset.

Plantronics Discovery 640 kit

The Plantronics has a Bluetooth radio that's v1.2 and works with both Hands-free and Headset profiles. We tested the headset with mobile phones in both camps including the LG VX9800 (The V), the Nokia 6682, the Nokia 9300, the Treo 650 and the E-TEN M600 Pocket PC Phone. The Plantronics paired with all easily. To pair the headset, press the multi-function button when the headset is off. When LED flashes blue and red alternately, the headset is in the pair mode. Use your phone to discover and connect to the headset using 0000 as the default pass code. The Discover 640 has the multipoint technology implementation; this allows you to use the headset with two Bluetooth audio devices.

The Plantronics supports voice dialing, call rejecting and mute features if your mobile phone has these features. You can initiate, answer and end a call using the multi-function button. To mute while on a call, hold the volume up and down buttons simultaneously until you hear a beep, and do the same to unmute. If you carry the headset in the carrying pocket, the carrying pocket will vibrate when a call comes in, and when you take the headset out of the carrying pocket, the headset will answer the call.

The voice quality on the Plantronics Discover 640 is very good. The incoming calls are clear and loud when receiving calls from several cell phones and land lines. You won't hear any hint that you are using a Bluetooth headset on a cell phone. The outgoing voice quality varies a bit. The LG VX9800, Nokia 9300 and Nokia 6682 saw the best outgoing voice quality with great noise cancelling and clear sound quality. The only device that experienced slight sound quality degradation is the Treo 650 which is a trouble maker for most of the headsets we've tested except the Treo 650 Wireless headset offered by Palm. The outgoing voice volume through the Treo 650 is lower than on the other devices and there is occasional crackling noise and it's a slight tinny on the outgoing voice.

The Bluetooth range between the Discovery 640 and the handsets did not reach claimed 33 feet. This is not uncommon as we found most of the headsets could not offer the 10 meter range in wireless-polluted areas such as the Silicon Valley. The Cardo Scala 500 had one of the best ranges and barely made 30 feet in our test. The Plantronics can get up to 20 feet with most of the phones in our test, except again the Treo 650 which can't make over 10 feet before you can hear crackling noise and break-ups in the incoming voice. The Bluetooth v1.2 is better than the previous version, but not that much better.

The Plantronics Discovery 640 comes with a rechargeable Lithium Ion battery. The claimed talk time per charge is 5 hours, which comes close to our test result which was about 4 hours. We found that it's convenient to use the AAA battery charging adapter on a short trip as you don't need to bring an A/C charger, only a triple-A battery which is small and can be found anywhere. A single battery will extend your talk time for at least 10 hours if not more. The standby time is a little over 2 days which is on the low end compared to other Bluetooth headsets. The headset will give you various warnings via both the LED and sound alerts when the battery is running low.

There is a lot to like about the Discovery 640. If you are one of the "in ear" headset users, the Plantronics is not to be missed, as long as you are not using a Treo 650.

Pro: Sleek design with an excellent packaging and presentation. Super lightweight and very comfortable to wear for long period of time. The incoming voice quality is excellent and the outgoing voice quality is very good on most of the devices. The headset is easy to use and operate. Supports some most common phone features such as voice dialing, mute and more.

Con: The outgoing voice quality and volume didn't perform well on the Treo 650 which is a big market to miss. Bluetooth range isn't super: average when working with most phones and poor with the Treo 650. The battery life is on the low end of the pack compared to other Bluetooth headsets.

Package contains the Discovery 640 headset, a headset carrying pocket works like a charging station, a battery charger with a AAA battery chamber, one AAA battery, charging adapters for handsets by Nokia, Sony Ericson, Siemens and Motorola, three soft gel ear tips in different sizes, an optional ear stabilizer, and a chrome carrying case that is designed all the items above in one small case. Finally, an A/C adapter.

-Bluetooth v1.2.
-Profiles supported: Hands-free and Headset.
-Claimed talk time: Up to 5 hours on a charge, increasing to 15 hours using the included AAA charger.
-Claimed standby time: Up to 70 hours.
-Range: 33 feet.
-Headset weight: 1/3 oz. (9 grams).
-Battery: Lithium Ion.
-AC adapter: 100-240v.

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