Velodyne Acoustics Digital Drive Subwoofer About Room Equalization, Distortion in Loudspeakers

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About Room Equalization

This section gives some background on room equalization. As a sub plays in a room, the reflections of the sound waves off the walls create “standing waves,” that is, places in the room where certain frequencies are louder and others are diminished. In addition to standing waves, every room will also have locations where cancellations of the sound waves are like black holes that no amount of attenuation can fill. Thus as a general rule it is better to “cut down” a peak of response rather than to “boost up” a valley (i.e. possible black hole) of response.

In general, you are looking for a frequency response that is +/- 3dB at all frequencies (it is highly doubtful that your ear can tell a response that is any better than this). The response will always roll off at the low end (according to the settings of the subsonic filter), and there should be no dip or peak at the crossover frequency with the satellites. While the goal is perfectly flat response, this may not be possible in the higher frequencies of the subwoofer’s response due to peaks or valleys introduced by the satellites.

Distortion in Loudspeakers

Nonlinear distortion is a problem that plagues all speakers. This particular type of distortion is a common problem in subwoofers, which must move large amounts of air to produce adequate levels of deep bass. Nonlinear distortion is defined as any form of distortion that moves energy from one portion of the audio frequency spectrum to another. When a single tone is applied to a nonlinear system, the result is harmonic distortion in which some of the energy leaves the system at multiples of the original frequency. When multiple tones are applied, intermodulation tones are produced, usually as simple combinations of the input frequencies. Generally, 3% distortion is considered a reasonable amount for speakers. This means that 3% of the total energy leaving the speaker is at frequencies other than the intended input signal.

Most subwoofers on the market today however, produce much more than 3% distortion at common listening levels. Many models we have tested produce greater than 20% distortion at 20Hz when driven to 100dB. This is a typical output level obtained in many systems, particularly home theater systems. Even at 1 watt, many conventional units produce several percent distortion. Secondly, the odd order, higher harmonics are much more offensive to the human ear than the closer 2nd harmonic.

An interesting result of this reduced distortion is that some of the bass, when played over an extremely accurate subwoofer system, seems to actually be missing. The truth, however, is that the “missing” bass was never there to begin with! Distortion products of conventional woofers actually add to the bass spectrum making it appear louder than recorded. This is due to the additional and unwanted harmonics (distortion) of the fundamental signal. While conventional subwoofers offer little to combat distortion products, we at Velodyne have developed another way.

The Velodyne Digital Drive Servo-Control Solution

Velodyne Digital Drive subwoofers produce sound in the same manner as conventional loudspeakers: a cone-shaped piston is forced to move by means of a linear motor. However, this is about the only conventional part of the subwoofer.

We determined that conventional motors are unacceptable when called upon to produce the amount of linear motion we desired. This inadequacy led us to design an improved motor structure by incorporating two coils, operating out of phase in a push-pull configuration within two magnetic gaps and suspended

Velodyne Digital Drive User’s Manual

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Contents Digital DriveTM User’s Manual Important Safety Instructions Wichtige Sicherheitshinweise Risque d’électrocution Ne pas ouvrir Table of Contents Congratulations Prior to InstallationProduct Features and Controls Package ContentsRemote Control Buttons Remote ControlSubwoofer Controls and Ports Installation OverviewDigital Drive Accessory Kit Subwoofer Cable Connections Installation Step-by-StepWord About Subwoofer Outputs Word About Interconnect Cables Onscreen Programming and SetupWord About Connecting More Than One Subwoofer Introductory Screen Onscreen Programming and Setup OverviewEQ Setup Screen System Settings Screen Onscreen Programming and Setup Step-by-Step Upon pressing 5, you should see the following screen Velodyne Digital Drive User’s Manual Word About Room Placement Velodyne Digital Drive User’s Manual Velodyne Digital Drive User’s Manual Velodyne Digital Drive User’s Manual Velodyne Digital Drive User’s Manual An equalized room is shown below Velodyne Digital Drive User’s Manual Velodyne Digital Drive User’s Manual Velodyne Digital Drive User’s Manual Runtime Mode Restoring DefaultsDistortion in Loudspeakers Velodyne Digital Drive Servo-Control SolutionAbout Room Equalization Care of Your Digital Drive Subwoofer Troubleshooting and ServiceProtection Circuitry Digital Drive Software UpdatesDD in and OUT Port Pin Configuration Com Port SetupIntroduction Byte NumberRS-232 Commands Other Velodyne Subwoofer Products Velodyne Acoustics, Inc

Digital Drive Subwoofer specifications

The Velodyne Acoustics Digital Drive Subwoofer represents a significant advancement in home audio technology, designed for audiophiles who desire deep, powerful bass without compromising sound quality. This subwoofer integrates cutting-edge features and innovative technologies to deliver an unparalleled audio experience.

One of the most notable features of the Digital Drive Subwoofer is its patented Digital Drive technology. This system utilizes advanced digital signal processing to produce precise bass response, eliminating distortion and enhancing clarity. The result is a dynamic sound that can fill any room, making it ideal for both music and home theater applications.

The subwoofer is equipped with a high-efficiency Class D amplifier that boasts impressive power output. This amplifier not only drives the subwoofer's cone effectively but also allows for significant headroom, ensuring that even the most demanding audio tracks are played back effortlessly. The combination of the amplifier with Velodyne’s custom-designed drivers means that users can expect deep, responsive bass that resonates throughout their listening space.

Smart EQ technology is another stand-out characteristic of the Digital Drive Subwoofer. This feature allows for automatic room correction, analyzing the acoustics of your space and adjusting the subwoofer’s performance accordingly. This ensures optimal sound quality tailored to your specific environment, eliminating issues caused by room acoustics that can degrade audio performance.

The subwoofer also features a sleek, modern design, making it an attractive addition to any home audio setup. Its compact form factor allows it to fit seamlessly into various living spaces, while still delivering rich, impactful sound. The Digital Drive Subwoofer provides multiple connection options, including both line-level and speaker-level inputs, enabling versatile integration with different audio systems.

Additionally, this model includes an intuitive remote control for easy operation. Users can conveniently adjust volume levels, phase settings, and EQ options, allowing for a customized listening experience. With its combination of powerful performance, innovative technology, and user-friendly features, the Velodyne Acoustics Digital Drive Subwoofer is a top choice for anyone looking to enhance their audio experience with rich, immersive bass.