Design essentials

Timing and phase correctness

Timing correctness is the most underrated quality aspect of a loudspeaker system.

The standard way of judging the quality of a loudspeaker system is by assessing its frequency magnitude response performance. This response curve is always highly influenced by the room acoustics characteristics and placement. It is relatively easy to correct these magnitude errors.

It is a different story for the phase-response curve, which shows the time-relationship and its variation over the frequency spectrum of the system.

Low frequencies are notorious difficult to be reproduced in a ‘time correct’ manner by a loudspeaker system. Crossover filters, mass and mechanical damping of the loudspeaker, a ported enclosure, all add to an increasing delay as the frequency gets lower. This ‘lagging behind’ or group-delay can easily add-up to values higher than 100ms (which equals close to 35 meters extra distance!).  These delays degrade the sound reproduction quality. Without proper measurement equipment, it is not always easy to identify this as a sound-system design-error and adequate correction is often not possible afterwards.

Speech intelligibility, tight and punchy dynamics, the accuracy and stability of instrument placement in the stereo-image, are all influenced by the phase-response behavior (the less deviation, the better the result).

All Brooklyn-Audio systems are designed with an identical phase-response signature. They deliver a perfect flat response from 300Hz and up, within a narrow 40º window. As a result, all frequencies are reproduced in a ‘time-correct’ manner, contributing to an excellent impulse response.

Loudspeakers with a different phase-response cannot be combined within a system, as their difference in group-delay result in incorrect summation. This behavior badly affects the frequency magnitude response.

As all Brooklyn-Audio systems share an identical phase-response signature, they can be used in any combination. The complete product range has been designed with this flexible modular concept in mind.

 

Impulse response

The impulse-response shows the ability of a system to accurately reproduce and follow the dynamics of a signal. A perfect impulse-response is an infinitely short peak with no overshoot and no decay.  In real-life this perfect response is impossible to realize, as electronics and mechanical properties of loudspeakers all have limitations.  Nevertheless, the impulse response delivers a clear indication if the various system components are perfectly time-aligned with a matching phase-response. Overshoot, smearing and decay should be as low as possible. Besides selecting the best drivers for the task, controlling the drivers with amplifiers that have short cabling connections and a high damping-factor contribute to a better impulse-response. This is one of the primary reasons why Brooklyn-Audio chose to integrate the amplifiers and cabinets into self-powered systems.

Frequency response

Sub:

The Sub frequency spectrum (20-100Hz) requires the most energy to reproduce in a sound system. Most modern music contains a peak range from 50-80Hz and has often very little musical content under 30Hz. It is important that the sub can reproduce down to 30Hz with a high efficiency as this substantially adds to the quality perception of the overall system.  

The sound-waves that a Sub produces are practically omnidirectional, this means that sound is radiated evenly as a sphere into any direction. This sphere like radiation behavior in combination with the high energy involved and long distances that low frequencies can travel, contribute to ‘sound spill’ problems at concerts and events, which can often lead to neighborhood disturbance complaints. The most efficient solution to deal with these problems is to ‘focus’ the sound-waves into a directional projection pattern with a cardioid setup. By careful positioning and DSP-processing, Sub radiation patterns can be ‘steered’ and focused.  

Brooklyn-Audio sub-woofers contain built-in system-presets to support ‘end-fire’ and ‘cardioid’ configuration without the need for any additional external processing. These ‘plug-and-play’ presets require no addition measurement and alignment procedures and make it very easy to absorb rear-radiating low frequencies, reducing the risk of spillage related complaints.   

Low-mid:

The Low-mid frequency spectrum (100-300Hz) is very important in the reproduction of dynamics and ‘headroom’ perception of the system. Almost any instrument and vocals have essential content in this frequency-range. We notice many system-vendors struggling with the trade-off between quality and SPL, as this frequency-range is very demanding on the drivers and prone for excessive distortion.

All Brooklyn-Audio systems are equipped with components that excel in this spectrum and are over-dimensioned to guarantee a low distortion reproduction with ‘tons’ of headroom.

High-Mid:

The High-mid frequency spectrum (300Hz-6kHz) covers most of the vocal range. The spectrum between 2-4kHz is the most sensitive area of our hearing. A few dB too much can lead to an unpleasant listening experience, while a few dB too little can cause problems with speech intelligibility.

All Brooklyn-Audio systems are equipped with components that are selected for low-distortion and low-coloration in a wide dynamic range and processed to an ultra flat frequency response and linear phase response.

High:

The High frequency spectrum (6-20kHz) is important in producing essential harmonics that are critical for the detailing of character definition from various instruments. We see many system vendors applying a hi-shelf correction to add ‘a liveliness color’ to the overall impression, masking the problems that result from incorrect transient impulse reproduction. This leads to an overall instable and ‘hyped’ sound-image and contributes to listening-fatigue.

The Brooklyn-Audio high frequency reproduction is tailored to represent exactly the source, no more and no less. This results into a relaxed and detailed listening experience even at high volumes.

Typical phase and frequency response of the Prospect top in 100Hz preset.