Review: Jamo D 7 THX Ultra 2-System

Reviewed by Carsten Rampacher, August 11th, 2003

Equipment

The one who is looking for an acoustically seen outstanding loudspeaker system, which is able to accomplish the THX Ultra 2 standard, does presently not have a wide selection at his disposal, yet. Besides Berlin’s loudspeaker manufacturer called Teufel and some US-American loudspeaker suppliers also the Danish sound experts from Jamo dispose of a THX Ultra 2-set in their product range. The D7-PEX set was tested in the colour stone-grey with a black fabric-cover. 

To our complete 7.1 set five main loudspeakers D7LCR (front left/right, centre, 2 x surround back, in this case with direct-emitting loudspeakers, two dipole loudspeakers D7SUR for the surround sounding and two active subwoofers of the type D7 SUB are belonging to. The suggested retail price of our testing system amounts to EUR 10.398,-- The one, who has got a home cinema room smaller than 40 square metres, can renounce of (comment from the manufacturer) the second active subwoofer (single price of D7SUB is EUR 1.899,-- per piece) and achieves a price of EUR 8.499,--.

With a frequency response from 20 Hz up to 40.000 Hz at -6 dB the D7-system is also suitable for high-resolution audio formats like DVD Audio and SACD. In connection with the new THX Ultra 2 standard, which also contains a music mode in the THX-history the first time, THX permits itself a higher vertical emitting angle at the front loudspeakers, leading to a more expressive music reproduction not sounding so unemotional as it was hitherto the case at THX-systems. 

To the individual components:

D7LCR: 3-way-loudspeaker (loading long-term 200 W, short-term 400 W), two woofers (5,5''), two midrange loudspeakers (2,5''), a tweeter (1''), midrange loudspeakers have been installed vertically over respectively under the centrally positioned tweeter, on the left and right side of this midrange / tweeter arrangement the woofers are to be found. The crossover frequencies are at 400 Hz and 2 kHz. The loudspeakers (efficiency: 89 dB/1 m/2,8 V) are magnetically shielded. As front loudspeaker three identical boxes are used and therefore it is recommended to fix these loudspeakers all in an identical height in accordance with a very homogeneous reproduction. Use as front-, centre- and back surround box.

D7SUR (loading long-term 100 W, short-term 250 W): Identical drivers as it is the case in D7LCR are used. Following to this phase transformations can be achieved, which are smoothly connecting to D7LCR. Result: A similarly high-graded precision at the reproduction – our summary in detail can be taken from below.

Of course a dipole is not working with the same precision as a direct-emitting loudspeaker - within the framework of principle design however the technicians of Jamo realised an optimum. Equipment: a 5,5'' woofer, four 2,5'' midrange loudspeakers, two 1'' tweeters. The crossover frequency for the woofer is 200 Hz. The woofer is situated in the centre of the housing front. This arrangement has been selected because conventional dipole loudspeakers (with two woofers) are suffering from bass weakness due to frequency extinction. By means of the equipment with a centrally positioned woofer not only this problem can be solved – additionally the depth of the housing remains small which facilitates installation and integration.

This is not only the case in theory, but also in practice which can be confirmed later on by our testing impressions. D7SUR (efficiency: 87 dB/1 m/2,8 V) offered a satisfactorily complete sound picture with a not only voluminous but also precise surround sound scenery.

D7SUB: 15''- woofer chassis, 400 watts (sinus) class D-amplifier, power surges up to 700 watts, standby-electricity consumption below 1 watt, with boundary gain compension. This filter compensates the acoustical influence of the testing room to the bass of the subwoofer. Deepest frequencies will be amplified by each kind of room, the size of this amplification of course depends of the testing room itself, however also of the hearing position. Normally the size of the value arises at the reduction of the distance between the subwoofer and the testing room wall. An increased bass level from 60 Hz is the consequence of this action. In the range from 20 up to 30 Hz even accelerated peaks from 5 up to 10 dB are resulting in for normal-sized rooms. Which seems to be impressing for the film sound reproduction is often disturbing for an accurate music reproduction: The bass peaks are the reason why unsightly noises of vibration are arising. The boundary gain compension is started at 55 Hz ( - 3 dB) and is damped up to 10 dB at 20 Hz. 

Normally each THX Ultra 2-amplifier or receiver is equipped with this boundary gain compension – however for the one who does not dispose of this feature of equipment at his THX decoder, Jamo still has got a “special feature” available: The boundary gain compension has already been built in D7 SUB by means of a separate cinch-input so that the D7-system can also be adjusted with all its advantages to already available equipment. The controller for the input level is positioned on the top of the D7 SUB-housing.

Totally seen the finish makes a good impression, whereas some details still can be improved, e.g at a loudspeaker system of this price class it is not appropriate to use a normal mains plug. Additionally the connecting terminals for the loudspeaker cables on the backside of the boxes could have been more high-grated. The fittings of the loudspeaker chassis however can completely convince due to its clean finish. Besides this the material of the housing makes a very resistant and long-life impression. 

Acoustical performance 

Testing equipment:

• DVD-Players Marantz DV12S1, Harman/Kardon DVD-30

• AV-Amplifier Denon AVC-A1SE upgraded, Onkyo TX-DS989 Upgrade 2

• Software: ID4 (Dolby Digital 5.1), Sleepy Hollow (DTS ES Discrete 6.1), Lord Of The Rings (Dolby Digital 5.1 EX), THX Ultimate Demo Disc, DTS Music Experience Studio Voodoo (DTS ES Discrete 6.1), DTS Demo Disc Nr. 4 (DTS 5.1 und DTS ES Matrix 6.1) Naxos Musical Journey, Johann Sebastian Bach: Violin concerto, "Bachwerkeverzeichnis" 1042 and violin concerto "Bachwerkeverzeichnis" 1041 (DTS 5.1), audiophile music for Dolby Pro Logic 2 (Audio-CD), Best Of Rock and Blues Soundcheck (Audio-CD), classic audiophile (Audio-CD)

Especially conspicuous at all home cinema testing examples: Both subwoofers are providing with a bass pressure almost comparable with professional systems. However not only its power convinces, but also the extremely high-levelled precision. It can also be noticed that there is no lost in dynamics respectively no disturbing distortions are arising; the high-quality construction of the bass loudspeakers effectively avoids unwelcome vibrations and noises. 

For the one, who wants to have a perfect bass power, we are advising in fact to use two D7SUB, especially if the home cinema room exceeds a size of 35 square metres. The 40 square metres, recommended by Jamo for the use of 2 active basses are principally seen completely all right. However the one, who prefers an extremely intensive bass reproduction should already use two woofers below 40 square metres. 

However not only both bass loudspeakers, but also our remaining testing candidates, achieved a great success, which also surprised experienced testers due to its finish.
Above all remarkably was the first-class detail reproduction of D7 front/centre/surround/ surround back-loudspeaker, which also made quiet film scenes to a special event. Not important if we are talking about the roaring of the sea in the background, soft voices, the sound of a music instrument which can be heard softly from the neighbourhood - all kinds of effect, small ambient noises or even more loudly sounds from the foreground are presented by the set of D7 at its best advantage. 

Also the dipoles are working at reference level by offering an extremely complete sound picture with regard to their construction principle – which can e.g. be heard in the initiating sequence of "Lord Of The Rings". Here the surround-sound scenery is voluminous and very precise. The absolutely homogeneous front effect scenery suits with the first-class total impression. The voice reproduction is excellent, each even very small detail is represented which means that, as already mentioned, not only at action spectacles but also at more quiet films a real hearing pleasure can be achieved, as every detail is lively presented by D7-set. 

Also in the multi-channel music mode the performances of D7-loudspeakers have been excellent. At the concert of violins composed by Johann Sebastian Bach the outstanding detail presentation surprised us a lot, which is above all at THX-certified home cinema systems not always the case. With the introduction of the THX music mode it seems to be the end of slightly inexpressive music reproduction due to the reasons as indicated in the technical description (e.g. higher vertical emitting angle). Already Teufel’s Theater 8 (round about EUR 4.000,--cheaper than Jamo’s D7) convinced with an outstanding performance during musical operation and Jamo D7 even achieved more: With a very clear and lively presentation of all instruments, Jamo-set also convinced demanding music fans. However not only classical music, but also pop- and rock music are excellently presented by D 7-set. The voice of Roy Orbison at his known music hit „Pretty Woman“ is incorporated very sensitively by the loudspeakers of Jamo, presenting all instruments very accentuated at the same time. 

The next surprise was delivered during stereo operation, where we expected good, however no performances above the average from Jamo-set. The result was however different than it was to be expected – exceptionally we had such a convincing co-operation between pretty compact front loud speakers and very strong active subwoofers. The subwoofers showed themselves integrated at an optimum, never a bass sounded loudly, however the extreme power of the bass was always noticeable on a very cultivated level.

Summary

The Jamo D7-system is extremely expensive, however the purchaser receives for his money a completely convincing equivalent. The one, who is still not satisfied with the outstanding features of Teufel’s Theater 8 receives with D7 a set of loudspeakers which is justified to the highest demands and which almost achieves the performance of professional sound systems. 

Reference
High End class
August 11th, 2003

Value

Pro:

• Level strength equally to professional systems
• Suitable for extensive home cinema rooms
• Extremely strong and at the same time precise bass with two active subwoofers 
• Active subwoofer with a dynamics far more than the average 
• Surround-sound scenery with an excellent volume and a first-class precision
• Subwoofer with an integrated boundary gain compensation
• Practically perfect voice presentation in the multi-channel music and film operation 
• Very good finish

Contra:

• Subwoofer without plug connection for cold appliances
• Very high price

Reviewed by Carsten Rampacher
Assistent: Matthias Walther-Richters

2003/08/11

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