June 2005


The Joy Begins...
Combak Bravo Loudspeakers
Review By Phil Gold
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  Now here's a loudspeaker I can appreciate — an honest attempt to build the highest quality point source design. Tannoy famously pioneered this route as early as 1946 with their dual concentric driver, and the Tannoy corner reflex cabinet was my father's pride and joy for many years. The objective behind this approach is to improve off-axis performance and widen the sweet spot. Tannoy's drivers, available in 10", 12" and 15" diameters were very expensive in their time but the performance of these large drivers, with their crossover frequency at a low 1kHz, fully justified the price. They were very popular in recording studios all over the world.

Tannoy Dual-Concentric Driver

On this side of the Atlantic, Altec Lansing introduced the 604 series coaxial speakers at around the same time. In 1988, KEF followed with its Uni-Q midrange / tweeter, initially in an 8" diameter (pictured right). This design was refined over three subsequent generations of 6.5" diameter. Today the driver has a pressed steel chassis and features a soft cloth tweeter and a polypropylene bass cone.

Some manufacturers such as Lowther and RL Acoustique have taken a different path, offering a point source by means of a single full range driver, but I have yet to hear one that didn't leave me feeling something was missing at each end of the frequency range. Others such as Wilson have offered a D'Appolito configuration, with two larger drivers above and below a central tweeter, but while this offers vertical and horizontal symmetry, at any other angle the symmetry is broken and the full advantages of a point source are not realized. At the Montreal Festival Son et Image I experienced an exciting new design, the Eben X-Centric, which uses a D'Appolito design using two round drivers set above and below a vertically oriented ribbon tweeter.

In fact neither the dual concentric approach nor the single full range driver can actually function as a true point source, because their diameters are not zero. The smaller the driver, the better the approximation, and conversely, the less extended the bass response.

Now SEAS is following in the footsteps of Tannoy and KEF with another true coaxial design, incorporating a 1" tweeter in the centre of a 7" fiberglass mid/woofer, just slightly larger than the KEF Uni-Q. The cone of the woofer acts as a horn loading for the tweeter and the chassis of the dome unit represents the throat of this horn. SEAS claim two advantages for this design. The two drivers have identical acoustic centers, and their directivities in the all important crossover frequency region are practically identical. Thus it is possible to build a full range speaker with a fully symmetrical and stable radiation pattern combined with a smooth energy response. Gradient cooperated on the design of this driver, and used it as the only driver in their Prelude speaker (show image), and as one of three drivers in their Revolution speaker.

Combak Corporation of Kanagawa, Japan are well known for the Harmonix tuning devices, the Reimyo range of electronics, which includes the CDP-777 CD player reviewed here last year, and Enacom audio noise eliminators. The fourth string to their bow is the elegant Bravo! speaker that I'll be looking at today.

Mr. Kiuchi first introduced me to his Bravo! speakers at the CES this January, and I was at once struck that he would choose to partner the extraordinary $17,000 CDP-777 CD player with these diminutive units. They measure just 7.5" by 11.5" by 11" (WxHxD). Mr. Kiuchi explained that these speakers are made to his specifications by Finland's Gradient, whose Prelude bookshelf speakers are based on the same driver units, but using less expensive methods of construction and a completely different crossover. This Bravo! speaker looks gorgeous, and I had no hesitation in selecting it for one of my CES design awards. Even my wife likes the looks, and she bestows her approval sparingly. The Prelude on the other hand would not win any prizes for its looks.

The Bravo! is a closed-box infinite baffle design with a free-space bass roll-off of 12dB/octave and a total volume of only 8 liters. It is easy to drive with an impedance that never falls below 7 ohms and an 87dB/W/m sensitivity. It comes in a rich cherry or black finish.

I placed the Bravos atop 24" Target stands, away from the room corners and 20" from the back wall, angled in towards the listening position. I moved them around but I didn't find their location critical. They took the place of my reference speakers, Wilson Benesch Act 1s, a hard act to follow. My analog source comprised a Linn Sondek LP12, Clearaudio Virtuoso Wood cartridge feeding a Graham Slee Era V phono preamplifier, while a Meridian G08 CD player did the digital honors through its balanced outputs, alternating with a McCormack UDP-1 universal player. Wiring was Nordost Valhalla throughout apart from the Cardas Neutral Reference phono cable, while the amplifier was the wide bandwidth Perreaux Radiance R200i.

This is very much a Jekyll and Hyde speaker. On some music the Bravo performs remarkably well, while on some discs the drama and scale of the music is missing. Now you wouldn't expect these pint-size speakers to kick out deep bass, and they don't. What surprised me is that they extend down quite a long way, and then the response drops off very sharply at around 60Hz. So if the music has little content below 60Hz, the Bravo will sound like a full range speaker, but if there is significant deep-bass content in the recording, the Bravo will sound like there is something missing. This is my one big knock against these speakers, and against all small speakers to a greater or lesser extent.

Some small speakers feature a response hump near the bottom of their range to give the impression of a powerful bass, but that is not the case here. Any bass you do get is clear, tuneful and well balanced. Although I didn't try it, I imagine that a well-matched subwoofer would do wonders for these speakers, and I have heard that Mr. Kiuchi is planning a pedestal subwoofer to go underneath the Bravo. Subwoofers would not solve the problem for speakers that do feature that bass hump, so Mr. Kiuchi has made the right decision here.

You won't overpower these speakers easily. I turned up the wick expecting some kind of overloading or distortion but they simply went louder until compression set in at high listening levels. Acting as a virtual point source, imaging is first rate, and there is no hot spot to worry about-–you can move around the listening area freely with no sharp changes in response. So what tracks show these speakers to best advantage, and what should you avoid?

Top marks for Patricia Barber's Gotcha fromthe new Classic Records release "Patricia Barber Live: A Fortnight in France" [JP 5007]. This features the best percussion sound I've heard in my home. The bass is quick and tuneful, if a bit restrained. The guitar has a very fine tone. The speakers fill the room easily, and show very fast reflexes. The soundscape extends well beyond the speakers and the level of detail is high. There are plenty of harmonics above the piano notes, while Barber's voice is clear and present. All is right with the world. Dansons La Gigue offers surprisingly strong bass and a rich midrange, while the applause is some of the most realistic I've ever heard. But there is a slight lack of extension at the top end. Crash shows us Jekyll and Hyde simultaneously. The music really swings, and the upper bass is strong. There are lots of separate lines flowing on this track, each located distinctly in space, but the deep bass is missing in action, leaving a somewhat hollow sound, and the abundant high energy treble can be harsh at times.

Thelma Houston's I've Got the Music in Me from the disc of the same name [Sheffield Lab 2] finds the singer in outstanding form. Each musical strand emerges clearly and the sound is involving and colorful, far from analytical. But again the bass power and drive is missing. The top is exemplary and there is no overhang on the difficult to reproduce percussion strikes. Reggae Tune's deep walking bass is almost inaudible, the effect of that sharp bass cutoff, leaving a bit of a hole in the centre. But the midrange contains a lot of detail and color.

Mozart's Clarinet Quintet [ASTREE E8736] should be a no-brainer for these speakers. The sound of the period instruments is stunning, especially the clarinet itself, which sounds much closer to a violin than the modern instrument would. The full width and depth of the recording space is revealed, but some of the gravitas is missing. Bartok's Concerto for Orchestra again shows good width and depth, and the sound remains consistent from floor level to a standing position. The transition between the two drive units is ideally smooth. The brass fanfares are clear, but there is not a lot of air above them.

Prokofiev's Ivan the Terrible [UDSACD 4003] suffers a slight lack of presence. The menace I can hear through the reference speakers isn't there with the Bravo. These speakers don't do menace. The wide frequency sound on this recording is rolled off at both ends. A limited dynamic range hinders the indication of scale in this music. The voices are warm and realistic, but are heard at a distance. But the massed orchestra shows surprising weight and the female voices show greater immediacy. The chimes are glorious. A mixed bag here!

Finally Mahler's First Symphony, an outstanding recording on DG [427 303-2], comes through very well on the Bravos, much to my surprise. They capture the full weight of the cellos and the horns shine clearly, never distorting. The strings have a realistic tone and reassuring weight. The orchestra is well laid out before us and it is easy to forget we are listening to a small speaker. The Bravos offer a lot of detail and capture the atmospherics superbly. The weight of the basses and drums is not captured but it is telegraphed, and the speakers show no sign of strain. The orchestral color is simply marvelous. Even my bird joined in at this point!

The Bravos are expensive at $4295 plus stands, and they clearly won't satisfy the head bangers among us. But they may be the perfect speakers for a high-end system in a smaller room, placed closer to the wall for bass reinforcement. They will suit many whose musical tastes do not extend to a bass-heavy repertoire, and I would expect some real magic from a well-matched subwoofer or two. They are exceptionally refined and colorful, image up a dream, and can handle a surprisingly wide dynamic range with ease. And they are a joy to behold! I enjoyed my time with these speakers.

Interview with Kiuchi-San

Q. I am particularly interested in how you tailored the bass response of this speaker, since it seems to be to go flat to around 70 Hz and then to drop off really sharply, but avoids a bass hump in the 100-200 Hz range.

A. As you know, Bravo! is made for us to our specifications by the Gradient speaker company in Finland and we supply wire and parts. When the Bravo! arrives from the manufacturer, we custom-tailor each one with our traditional resonance control technology so that the total frequency is flat, using our exclusive technical know-how.

Q. Can you comment on the physical construction of the speaker, the tuning device on the sides, and the design of the crossover?

A. The crossover was designed for us by the manufacturer, Gradient. We pay particular attention to resonance control. We maximize the potential of the network design by selecting the optimal material for the front baffle (solid wood not MDF), the tuning of the driver inside and the box itself, to smooth out the total frequency response, to make it flat and extended. The side tuning devices are included to reduce any unwanted noise that the box produces.

Q. I have noticed quite a bit of Internet discussion about the Bravo and the Gradient Prelude, so I thought I would ask you what the differences are between the two speakers?

A. There is a huge different between the two. The Prelude is a basic and simple model for the Bravo!

We designed Bravo! to be much more integrated and to be acceptable to serious music lovers. So we redesigned the front baffle to use natural wood, we designed and supplied the internal wires and so on. The speakers are so different that there is no point comparing them any more.

Bravo! is a bookshelf type of speaker. Some recording studios use Bravo! as their recording monitor speaker system and some engineers say Bravo! should not be called bookshelf, it is much more than that. They suggest I call it a "Reference Near field Studio Monitor."

Q. At CES you had the Bravos mounted on prototype subwoofers, the B-Bass. How is that project coming along?

A. I have brought the B-Base along with me around most of the shows over the last couple of years to judge listeners' reactions. I can now confirm that most customers like it very much. My confidence has been boosted by this feedback and I hope to have it ready for marketing by the end of this year.

Q. Do you have plans for any other speakers?

A. Yes, certainly, but not anytime soon. Maybe by 2009, I hope to finish another design of floor-standing speaker to be a suitable partner for the Reimyo PAT-777 300B tube amplifier.

Q. How do you decide on a product mix?

A. We are a small-scale manufacturer. For this reason, we can hardly make a wide range of product to cover all demand. Instead we wish to continue manufacturing unique and recognizable products based on our own traditional Harmonix Tuning technology. The products we make can provide the highest levels of enjoyment and appreciation for many years.

Specifications

Type: two-way coaxial closed box monitor loudspeaker

Drivers:
Tweeter: SEAS 25mm aluminum dome
Midrange/Bass: SEAS 170mm with fiberglass cone

Frequency Response: 80Hz to 20kHz (+-2.5dB), -6dB at 55Hz

Sensitivity: 87dB/W/m

Crossover Frequency: 2.8kHz

Binding Posts: 5-way, gold-plated WBT-0763

Features: Magnetic shielding, front baffle natural wood

Finish: Black or Cherry

Size: 7.5" x 11.5" x 11" (WxHxD)

Weight: 8 kg

Price: $4,295

Company Information

Combak Corporation
4-20, Ikego 2-chome, Zushi-shi
Kanagawa 249-0003 
Japan

Voice: 046-872-1119
Fax: 046-872-1125
E-mail: harmonix@combak.net
Website: www.combak.net