DEQX HDP-Express-II

1) Speaker correction:

• Frequency response. The performance of speakers, when considered in terms of frequency response, is an order of magnitude worse than that of the rest of the electronics within your reproduction chain. Typical best case (on-axis) speaker performance is +/- 3dB across the audio spectrum from 20Hz to 20kHz compared to +/- 0.1dB for the signal that leaves the amplifier.
• Group delay. The crossovers in most speakers create a frequency dependent delay or group delay which causes some frequencies to lag behind others in time. At 1kHz our detection threshold for group delay is around 2ms. A typical high end speaker can have group delays of 3ms in this critical frequency band! These group delays negatively impact our perception of  musical timing and coherence.

2) Room correction. Modal resonances cause peaks in the frequency response and ringing in the time domain. DEQX can reduce the audibility of these problems through implementation of parametric EQ filters.

3) Recording equalization. Quite a lot of recordings benefit from some level of equalization. The DEQX puts this at your fingertips - EQ can be dialed in from the listening seat via the remote control in real time.

4) Digital crossover:

• Distortion. Distortion figures of 1% are not uncommon amongst even high end loudspeakers. These high distortion figures are partially caused by shallow crossovers that do not roll off the signal to individual drivers enough to prevent them from operating in the region where their cones resonate and break up. A 6dB per octave crossover, often found in high end speakers because it is linear phase, would only reduce the input signal to a midrange driver by 6dB over the octave from 3kHz to 6kHz. This will almost always lead to high distortion at 6kHz as a result of cone break up and can also lead to narrow band peaks in the frequency response as a result of the associated resonances. DEQX can reduce distortion through its ability to specify steeper crossover slopes such as 48dB per octave. Another way to reduce distortion is to use a subwoofer. Subwoofers reduce distortion by removing the need for the main speakers to reproduce low frequency content. DEQX can manage the crossover between main speakers and a subwoofer or pair of subwoofers. A final cause of distortion is the passive crossover (comprised of resistors, inductors and capacitors) that sits between the amplifier and the speaker driver. Passive crossovers introduce intermodulation distortion and make the job of an amplifier very difficult indeed. Using DEQX in active mode it is possible to direct couple each drive unit to an amplifier channel which can lead to an measureable reduction in distortion.
• Dispersion. Operating drivers outside of their optimal frequency range results in beaming. Beaming naturally occurs where the wavelength of sound being reproduced by a driver is a significant portion of the driver diameter. Uneven dispersion typically causes frequency response anomalies at the listening position.
• Time alignment. Whilst some speakers used sloped or stepped baffles to time align drivers many do not. Lack of time alignment causes a loss in musical coherence and timing similar to that caused by high group delay. DEQX can be used to correctly align the arrival time of the signal from different drivers within a loudspeaker. DEQX can also be used to time align subwoofers, which are often placed further away from the main speakers near a wall or in room corners.

If you want to know more please watch these great videos from Kim Ryrie, founder of DEQX, who explains in more details some of the ways in which DEQX can improve your system.

Still have questions? Contact Us!