Bass was the jamo R 907 (8000 euros the pair) the competitors with their powerful and lifelike character literally derate.
- Dipole radiator jamo R907
- Technology in detail
- Data sheet
Vertically from the front the R 907 is looks like a normal three-way box. On top of the tweeter sits on the slightly curved baffle as usual here in the form of a 25 mm dome with large-scale sound leadership.
One level deeper is a mid-range cone with solid phase nose and ultra rigid magnesium membrane, including two unusually large woofer with Matt grey shimmering funnels made of air-dried paper fibres can be found.
As soon as sweeping views to the side, the jamo revealed their central feature: A case in the classical sense is not present only to a 44 cm wide baffle and a bombproof sitting metal bracket that extends from the rear of the base plate to the tweeter. The low – and midrange can swing freely in both directions fabric hoods attached under the left and right of the vehicle. A small, closed volumes only the tweeter is connected in series.
The open design kills two birds with one stone. The abandonment of large-volume Chambers usually eliminates the problems associated with boxes housings: resonating walls as well as roiling sound resonance garbage out of the housing, hitting time lag on the membranes.
And the design helps the large plane projectors with integrated diaphragms, but without weaknesses in bass depth and resilience of the sculpture to a dipole shaped dispersion pattern, similar to.
Behind the scenes, however, some pull-ups are needed for dipoles, because omitting the usual Chambers is not enough. Front and rear work offset 180 degrees and thus matched. Without countermeasures the noise components would offset at least in part.
As soon as the wavelength is greater than the distance from mid front chassis to the rear, sound pressure with a slope of 6 decibels per octave decreases with open construction. A woofer, which produces a linear bass in a closed housing, would openly mounted extremely thin sound.
At medium frequencies, the baffle of R 907 can effectively prevent the acoustic short-circuit. In the long-wave bass, countermeasures are required, that ultimately explain the large format of the woofer.
At 30 Hertz, the two achieve completely enjoyment-grade level 12-incher despite partial short circuit. The coupling of increasingly better at higher frequencies is compensated in the crossover. So, an absolutely linear bass response grows in total despite the loss of the dipole. So Watt, demand suggesting the use of powerful amplifiers. But unlike the short-circuit problem cannot be rectified. Open working surface spotlights – about electrostatic – are faced with the same problem. More about it here.
In the bass, the jamo R 907 could literally derate the competitors with their expressive and life-like character. The P 3.1 suffered their skimpy level reserves and had the dry hardness of the jamo bass pulses only little.
Here you can find the detailed hearing test.
The R 907 3.1 is similar to that of the P a dipole radiator, which directs its energy to roughly equal to the front and rear. But the statement applies only to the lows and mids, because in the high frequency range is a rear closed tweeter to the Usage. Low – and midrange shine, however, freely in both directions.
The turnout is in the base of the boxes included the installation conditions and ensures a balanced energy balance over all space angle across. As the pit measurements in anechoic room angle behavior of direct radiators are adapted, the three candidates went through an additional spin in the listening room. Not correlated noise was used as a signal. The results are improved readability, third band averaged. The micro was at the listening position in 3 to 4 meters distance. Since this Setup with captures the properties of space, the results are only limitedly transferable.
A disadvantage is that jamo opts for supposedly drifts dynamic converter. The Watt demand remain moderate despite dipole-induced losses in the low bass.
With good 82 decibels of 2 volts the jamo in the measuring room is full 6 dB more sensitive than the audio exclusive or that achieve the German Physiks, dB under the same conditions only around 75 or 76.
At same level, the jamo requires only about a quarter of the performance. R 907 is also ahead of the maximum volume. Minimum 10 dB more are already a Word.
Jamo R 907
Technical data and test results
|Installation tip:||free standing, distance to rear wall 2 m, normal damped rooms from 30 m ²|
|Operating voltage for 90 dB SPL||4.9 V|
|Impedance minimum stp||3.0 ohm|
|Maximum volume upper value||105 dB|
|Maximum volume lower value (> 45 Hz)||105 dB|
|Lower cut-off frequency (-3dB)||30 Hz|
|Lower cut-off frequency (-6 dB)||25 Hz|
|Short conclusion||Strikingly elegant and Valued dipole radiator with four dynamic drivers of a baffle. Sublime space with large depth and of still good locability. \ R \ nFull inaugural, premium basin, enormous level reserves.|
|Sound||Absolute top class|
|Sound points (70 points)||59|
|Overall rating (max. 120 points)||good – very good 79|
|Price / performance||Very good|
|tested in output||2 / 11|