The German Physiks HRS-120 Loudspeakers
As with all German-Physiks loudspeakers the key feature of the HRS-120 is the use of our unique DDD driver. One of the most important advantages of the DDD driver is the very high speed with which it is able to respond to sudden changes in the music. These are referred to as transients and are what gives music its sense of life and dynamics. The DDD driver’s excellent transient response would however be a disadvantage if you tried to use it with a conventional bass system. This is because conventional bass systems cannot respond fast enough to keep up with the DDD driver. The result would be that the bass would always sound like it was lagging behind the rest of the music, so when we designed the HRS-120 we had to find a way of producing a bass system that would match the speed of the DDD driver.
Back to the Drawing Board
We went back to the drawing board and using detailed computer simulation techniques, designed what we regarded as a perfect cabinet, but without the constraints involved had we designed with a particular driver in mind. This approach was unusual, as it is normal to look at the data for the available drivers and then design a cabinet to match the chosen unit. This would however have meant us accepting the limitations of the available drivers and this was a compromise which we were not prepared to make. Having designed our perfect cabinet, we set about designing a new bass driver that would be the perfect match. The resulting system comprises a cabinet with an integrated Helmholtz resonator and a brand new bass driver, both of which we are proud to say are built in Germany. The perfect balance of these components produces a bass that is very fast and dynamic, as well as being extended and well controlled. It is never blurred or bloated, as is often found with large speakers and it is perfectly integrated with the output from the DDD driver.
The DDD Driver
The DDD driver is used on all German Physiks loudspeakers and the same quality of driver is used on all models from our entry level product, to the top of the range Gaudi.
This revolutionary driver gives the same very important advantages to all German Physiks designs and is what sets them apart from our competitors. Its very low moving mass enables it to operate linearly over an extremely wide frequency range. The titanium DDD driver used on the standard HRS 120 covers the entire range from 240Hz to 21,500Hz. In a conventional design, this range would be covered by two or even three different types of driver and most importantly there would be a cross over point in the mid range, the area where our hearing is most sensitive. The DDD driver’s wide operating range allows this vital region to be kept free from the level and phase anomalies that multiple drivers and a necessarily more complex cross over would create. This enables the HRS 120, like all German Physiks loudspeakers, to produce very accurate and realistic stereo images. Another key advantage of the DDD driver is that it is omni directional, so these excellent stereo images can be enjoyed from a wide range of listening positions, unlike conventional designs which have much smaller “sweet spots” due to the tendency of their drivers to beam the sound. The benefits of the HRS 120 can be shared with friends and family, a feature that will be appreciated by any husband who has to negotiate upgrades of his hi-fi system with his wife. The DDD driver’s omni directionality also makes the HRS 120 less sensitive to room position than conventional designs. In addition, toe-in adjustment becomes unnecessary and this combined with the loudspeaker’s small foot print, make it relatively easy to set up in the listening room. The DDD driver’s very low moving mass provides the further benefit of exceptional impulse and phase response characteristics and allows it to reproduce both the attack of the music and resolve low level detail very accurately. This is essential in order to faithfully reproduce the delicate nuances and timbral characteristics of a performance and make it sound like music, rather than just good hi-fi. The driver’s excellent impulse response also ensures that the stereo image remains focussed and stable, even when the loudspeaker is reproducing complex passages at high levels. More information on the DDD driver, its development and advantages may be found on the Technology page of this web site.
Low Resonance Cabinet Design
One of the principle causes of degradation of a loudspeaker’s ability to resolve fine detail and thereby produce a sense of realism is the radiation of sound energy through the cabinet’s panels. To counter this, we designed the HRS-120’s cabinet panels to be as stiff as possible using the two pronged approach developed for our Carbon and Borderland models. Firstly, we use heavy panels of MDF with re-enforcements fitted to critical points within the structure. Secondly, we designed the cabinet with an octagonal cross section, so that the individual panels are smaller and therefore stiffer than they would be if a conventional square or rectangular cross section had been used. Any residual “cabinet talk” is minimised by applying a special damping material called Hawaphon to the inside of each panel. Hawaphon is a polymer sheet containing a matrix of small cells filled with very fine steel shot and was originally developed as an anti-surveillance measure for use in military and government buildings. It adds mass to the panel to reduce the resonant frequency and the ability of the shot in each cell to move against each other provides a very effective way of converting vibration energy into heat. Hawaphon achieves a broadband attenuation of structure-borne sound of more than 50dB, which is a remarkably high figure. To damp resonances of the air within the cabinet, the whole of the inside of the cabinet is lined with a thick layer of high density felt.
Adjustable High Frequency Output
Jumpers on the loudspeaker’s rear panel allow the high frequency output level to be adjusted in 4 steps: -2dB, flat, +2dB and +4dB. This allows the user to easily compensate for the variations in the absorption of high frequencies that occur due to different types of furnishings and room construction.
Designed for a Lifetime of Use
We use the same quality of parts in the HRS-120 as we use in our reference products, where we design for a minimum life expectancy of 25 years. We also apply the same meticulous care and attention to the manufacture and testing of the HRS 120 as we do with all of our other products. For example, the DDD driver support pillars, loudspeaker terminal mounting plates and all the screws and spikes are made from high quality V4 stainless steel. This provides excellent corrosion resistance and ensures that the HRS-120’s high cosmetic standard will be maintained over the product’s lifetime.
Hand Finished for Ultimate Quality
The German Physiks HRS-120 is available in the customer’s choice of hand matched, hard wood veneers. Cabinets supplied in our High Gloss option are coated with several layers of lacquer and then hand polished to a deep lustrous finish. This can be re-polished in the event of it receiving minor damage. Please see the Finishes page for more details. Our demo pair are finished in High Gloss.
Special Order Version
A special order version of the HRS 120 is also available. This is fitted with a carbon fibre DDD driver which provides an extended frequency response and greater low level detail resolution. The cabinet is finished with carbon fibre re-enforced panels. These provide greater rigidity, further reducing cabinet talk and improving transparency. The cabinet is coated with several layers of lacquer and hand polished to a high lustre finish. The result is a stunningly beautiful and luxurious finish. Like our High Gloss option, this can be re-polished in the event of it receiving minor damage. Our demo set are a special order version with carbon fibre and the larger woofer in high gloss lacquer finish.
German Physiks HRS-120
With Titanium DDD Driver
Short term: 160W
DDD section: 12dB/octave electronic & 36dB/octave acousticWoofer section: 2dB/octave electronic & 14dB/octave acoustic
With Carbon DDD Driver
Short term: 170W
DDD section: 12dB/octave electronic & 36dB/octave acousticWoofer section: 2dB/octave electronic & 12dB/octave acoustic