|B&K AVR307 Receiver|
|Home Theater AV Receivers AV Receivers|
|Written by Tim Hart|
|Friday, 01 February 2002|
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I’m a purist when it comes to all things audio. Being a purist, I prefer the simplest approach to creating music, meaning the least amount of circuitry in the chain from source to loudspeaker. Until the big wave of home theater came along, it was fairly easy to keep the focus on producing high-resolution music playback in my system, ever searching for that one component that would put me closer to musical truth. I’ve had to revise my philosophy on playback ever since I became enamored with home theater, as the hardware required to pull off the magic has to work through other components to be able to utilize all of the media we love to manipulate. Since home theater is so compelling, it wasn’t too hard for me to make the transition from audio geek to home theater dude. But I still have issues with how some products handle the all-important data. It gets very complicated when your system has to incorporate DVD-Video, DVD-Audio, video processors, component and S-Video inputs and outputs … the list gets a bit dizzying. On top of that, you need to pull it all off with minimal adulteration to your precious audio and video signals. That is a very tall order, as I’ve witnessed often when reviewing receivers.
The AVR307 receiver is a powerhouse command center from B&K ($3,498.00). At a solid 65 pounds, the seven-and-one-half-inch tall AVR307 sounds big, but dimensionally it is a bit smaller than other receivers in this class, most notably in its 17-inch depth and 17-inch width. The AVR307’s look is simple and a bit industrial in black (also available in gold and silver, as well as with optional 19-inch rack mount faceplates for an additional $100.00), but under the hood, it is a different beast. The real beauty of the AVR307 is its simplicity of use, discrete circuitry and straightforward audiophile design philosophy of utilizing quality parts throughout.
Part of the AVR307’s high-end heritage is its high-quality digital circuitry, along with Motorola’s 56362 DSP chip, which does the conversion to high-resolution analog outputs, and seven channels of 96k/24 bit digital-to-analog converters. Another strength is the use of MOSFET transistors in the output stage of the 150-watts-per-channel amplifier section to meet the demanding power handling requirements, transients and dynamics of a variety of movie formats, such as Dolby Digital, THX, DTS, 6.1 Surround, 7.1 Surround, and Surround EX. This makes the AVR307 one of the very few receivers able to take advantage of the newer formats without any additional amplification or decoding.
A feature I like is dual zone capability. The AVR307 has a D/A preamp/processor for the first zone, and an additional independent internal analog preamp for use in another room, allowing you to access your components from the main room by simply adding speakers. You can look at it as saving money by not having to buy more components.
To "future proof" the AVR307, B&K will be able, via the Internet and the RS232 connection on the back of the AVR307, to facilitate software upgrades. Also, if for some reason you have to send your AVR307 back for service, B&K will provide any hardware upgrades that are available at that time, bringing your unit up to date with the latest factory gizmos.
The front panel of the AVR307 is simple-looking, with a large, uniquely-shaped display and a large diameter volume knob above a headphone jack and eight buttons that control various aspects of the receivers functions, such as presets, menus, source selection, modes, enter, up and down select, sleep and save.
The back panel, although thickly populated, is laid out in an organized way. The seven speaker terminals occupy a third of the panel, giving ample room for bare wire, banana jacks or audiophile grade spade lugs. This is the only receiver I’ve seen that provides such roomy and robust speakers connections for what I consider one of the most important connections in your system.
If you’ve made the move to DVD-Audio, the AVR 307 will accommodate you, providing the necessary 5.1 analog inputs for your DVD-A player. The AVR307’s digital inputs are fixed to a specific data port, which can avoid some confusion when you have to assign a component to a specific port. Although this makes the AVR307 a little less flexible, B&K does give you 11 digital inputs, which should be more than adequate.
There are two control output "triggers" that you can use to turn on components in another room or trigger a movie screen. An RS 232 computer interface is provided for future software upgrades, as well as eight line-level outputs for driving outboard amps or decoders for future proofing, three S-video and RCA fixed level outputs for video or audio recording, seven S-video and RCA line inputs for your audio/video sources, an optical digital output, which is Zone 1, that will take the source information and port it out to any component able to decode it, six coaxial digital inputs for your source connections, and two coaxial digital outputs for independent control of Zone 1 and Zone 2. This gives you the multi-room control of other components. And if your remote won’t reach from one room to the next, there is also an IR input for adding an IR repeater to overcome obstacles in the way of your remote signal.
The interface for the AVR307 is a bit different than other receivers, but once you understand the logic behind it, it easy to set up the parameters of your system. Using the OSD (On Screen Display) for system setup, the menu structure is clear and simply laid out. The initial six menu picks on the main menu allows you to access the two zone setups and the system setup. Starting at the system setup first is the speaker menu for speaker size, location, levels, crossovers and LFE. The crossovers for each speaker can be set from 20-200 Hz in 5-Hz increments, and you can control the crossover slopes in 6 or 12 dB per octave for the surround channels. For the subwoofer, you can change the slope in 12 to 24 dB per octave, or you can use the external crossover setting, which utilizes the sub's internal crossover.
Room equalization can be very powerful if used correctly. The AVR307 allows you to use a test tone that is adjustable from 20 to 300 Hz to determine room modes. By using a SPL meter to measure the most offensive frequency, you can set the notch filter provided at that particular frequency and set up the notch width to have a range that centers on the notch frequency. For example, if the notch is set at 100 Hz, the notch width could be set from 96.6 Hz – 102.4 Hz. All of this is independent of other EQ settings and is engaged full-time. For the detail-minded person, this gives the user the tools to nail a room for the best response. This is the most flexible receiver I've experienced in terms of speaker setup, giving the AVR307 the ability to dial in your speakers to your room like never before. If you have patience, you will be rewarded with the most accurate sound your room might be capable of, especially at this price.
Another cool feature is called "favorite audio listening mode." You can set a default audio mode for each input source. When a source is selected from the remote control, the audio mode will automatically be set to use the defaults of your choice, such as output levels or number of speakers to use, to name a few.
For example, the AVR307 can change from two to seven speakers, or anything in between, for each input. If you were to use a DVD player to play CDs and DVD movies, you could play your CDs in two-channel stereo mode, and your DVDs in Dolby Digital and DTS in six-channel ("EX") mode. The AVR307 will automatically playback PCM CDs in two-channel stereo and Dolby Digital and DTS DVDs in Surround 6.
When switching between different components, you’ll sometime have different volume levels, as they do vary from manufacturer to manufacturer. The AVR307 allows you to level match all of your input source components and save those settings in "favorite audio listening mode."
The AV7.1 remote is a new version of their previous controllers, with new feature enhancements, such as differently-shaped buttons that are nicely spaced. They are all backlit by a bright blue light that is activated by the bottommost button, which allows the user easy viewing of all of the remote functions. You can access up to 40 presets, with the ability to assign a number to each one. The presets can control anything from equalization to surround modes at the push of a button, if you can remember the correct number. Be prepared to write them down, becausee I doubt that you’ll remember all of them, as there is no way to name each one.
When it comes to the problem of component selection keys, where you need one to switch the remote to command a component and the other to tell the receiver which input to select, B&K has multiplexed the seven component keys for dual function. If you press the CD key, the remote screen will display "CD." If you hit the button twice, the remote will keep some of the general functions active, like volume control or surround modes, while assigning most of the keys for the specific functions of the component selected. Pretty cool, once you get the hang of it.