The PQS-402 uses two DDD drivers, two 10-inch woofers and four 8-inch passive radiators to provide exceptional dynamics and resolution that will take you a step closer to a real performance

The bass system produces prodigious amounts of deep and well-controlled bass, that at the same time has the speed and finesse to perfectly match with the dual DDD drivers. The combined effect is a loudspeaker that can do equal justice to full-scale orchestral works, or a solo voice. This is further enhanced by the PQS-402’s very high maximum output level (118dB), which allows a closer approach to live music dynamics, without compression

The Problem

Because we wanted to cross over the DDD driver to the woofer between 220Hz and 140Hz, we had to find a way to build a very fast bass system that could match the speed of the DDD driver in the crossover region and also work down to 25Hz. To reproduce low bass at high levels a lot of air has be moved. This requires either a driver with a large surface area, which will be heavy and therefore not easy to move at the speed necessary to match the DDD driver, or a driver with a long excursion, which again will be heavy due to the rigidity required to withstand the necessary acceleration. Most loudspeaker designers solve this problem by producing a 3-way system. However, in a loudspeaker the size of the PQS-402, a 3-way solution would have been worse than a 2-way solution, due to the difficulty of making 3 drivers appear to be a single source. This is especially difficult with the mid and treble drivers, where the ear’s ability to locate position is very acute. It can be done, by why bother when you have a better solution?

The Solution

Our solution was to build a bass cabinet using a fast and powerful 10-inch driver and two 8-inch passive radiators. The 10-inch driver integrates flawlessly with the speed of the DDD drivers and the passive radiators extend the bass response smoothly down to 25Hz as required. The final system comprises 2 bass cabinets that are mounted one on top of the other and stand between a top and a bottom plate. None of these components is attached to the other using screws or any other form of hard connection. Instead they are held together by a system of interlocking collars. This, combined with the fact that the two cabinets have different weights, as do the top and bottom plates, means that resonances are reduced to negligible levels compared to a solid structure.

The DDD driver’s omnidirectional radiation characteristic and its very wide operating range, together with several other key features give the following important advantages to all German Physiks designs and is what sets them apart

1. Exceptionally coherent and natural sound

This is due to the DDD driver’s 7 octave plus operating range. This is very difficult to achieve when such a wide range is split over two or more different types of driver, which are in different positions on the loudspeaker’s cabinet.

This wide operating range also eliminates the crossover point in the mid-range that loudspeakers using pistonic drivers must have. This is where our hearing is most sensitive, so removing anything that might cause level or phase errors from here will improve transparency.

2. Realistic stereo images more like those you experience in the concert hall

This is because the DDD driver's omnidirectional radiation characteristic creates an enveloping sound field like that in the hall, rather than beaming the sound at you as conventional drivers do. This way the PQS-402 is able to recreate a more natural rendition of the original stereo image. This has excellent depth and focus, but without the overly sharp image definition that some hi-fi loudspeakers produce and which you will rarely if ever hear at a live performance.

3. Stereo imaging enjoyable in almost all positions in the room

This is achieved whilst also maintaining an even tonal balance, much like at a live performance: again due to the DDD driver’s omnidirectional radiation pattern. This gives more flexibility in where you sit and allows several people to enjoy a good sound together. This is useful in home theatre systems.

As you are not restricted to a small “sweet-spot” in order to hear the best sound, the PQS-402 provides a more relaxed listening experience. This is especially noticeable when you listen for long periods.

4. Exceptional dynamics

The DDD driver’s very low moving mass, less than 3 grams, allows German Physiks loudspeakers to recreate both the attack of the music and resolve low level detail very accurately. This is essential in order to faithfully reproduce the delicate nuances of a performance and make it sound like music, rather than just good hi-fi. The resultant transparency is maintained even on complex high-level passages.

5. Accurate portrayal of musical instruments’ tonal characteristics

This is because the DDD driver is phase linear across its operating range. This together with the excellent dynamic response, enables the PQS-402 to reproduce percussion with startling reality. Voices have a clarity and purity that can be breath taking, with all the elements of the vocal sound correctly located in space and with no undue emphasis. The hardness you often hear with conventional tweeters is eliminated and you get a greater sense of hearing a live musician.

6. Quick and easy to set up

As they are omnidirectional, German Physiks loudspeakers are less sensitive to room position than conventional designs and there is no toe-in adjustment to worry about.

7. The DDD driver is less likely to excite cabinet vibrations

Due to its very low moving mass and the way that it is mounted, the DDD driver puts less energy into the cabinet than an equivalent conventional driver. This reduces cabinet resonances and improves transparency.

8. Physically extremely rugged

The DDD driver can withstand abuse that will destroy most other drivers. Thisis illustrated in the video below. We don’t advise our customers to try this, just in case they are having an unlucky day.

For a more detailed explanation of these points, please follow this link.

More information on the DDD driver, its development and advantages, please follow this link.

Patented Crossover Design

The crossover provides a wide range of adjustment to allow the PQS-402 to be better set up to suit the user’s listening room. The high frequency level may be adjusted over the range -2dB to +4dB in 4 steps and the low frequency level may be adjusted over the range +10dB to 0dB in 3 steps. The low frequency control has no effect above 100Hz and we have applied for two patents to cover the novel approach that we developed to achieve this. Both controls are facilitated by high quality jumpers located on the loudspeaker’s rear panel and may be quickly and easily adjusted.

Bi-wire or Bi-amp

Two sets of high quality WBT nextgen™ loudspeaker terminals are fitted allowing the PQS-402 to be bi-wired or bi-amped. High quality jumpers are supplied to enable the loudspeaker to be used with just one set of loudspeaker cables.

The PQS-402 may be ordered in an active version, where the internal passive crossover is omitted and the woofer and DDD driver sections of the loudspeaker are driven directly by two separate power amplifiers. This allows much better damping and control of the drivers and provides a noticeable improvement in transparency.

The table below shows the recommended amplifier rating for each section of the loudspeaker:

The active version of the PQS-402 is supplied with our new Emperor Extreme DSP based digital crossover. This is a high quality unit constructed using premium components and is housed in a heavy steel and aluminium chassis.

The crossover is preconfigured at the factory allowing the customer to use it straight away without needing to make any further adjustments. The customer can manually adjust the settings if they wish.

The system allows a number of crossover set-ups to be stored and quickly recalled. This makes it easy to experiment with new settings, safe in the knowledge that the original settings can easily be restored.

For further information on the Emperor Extreme Crossover click here.