Onkyo D-302 E

Small, stylish speakers based off of a unique design.

Two-way bookshelf speakers are like car engines. The concept and the techniques are age-old. For decades now many actors in the field have thought that there’s absolutely nothing new and inspiring that can be said about the concept. As a consequence, every new 2-way bookshelf speaker is treated like a wheel reinvented, a gnawed-out bone.

Yet new models and brands are showing up at a regular pace, and from every corner of the world. And just like car engines, they seem to keep improving too, at least in the lower price categories. Not by a giant’s steps perhaps, but still.

This is a small story of a small speaker, Onkyo D-302 E. Onkyo? Isn’t Onkyo better known as a manufacturer of quality products for those who care more about their own fidelity than that of their music playback system? Maybe that reputation comes from Onkyo’s recent efforts to develop serious AV-electronics for home theatre applications rather than to shine in the limelight of the two-channel world. 

But once a bit longer historical perspective is allowed, it’s clear that Onkyo’s been one of the truly pioneering companies in Japan in many areas of audio (stereo) R & D along with firms such as Luxman. During the 60 years of its existence this year – Congratulations, by the way! Onkyo has developed many innovative products from the CP-1000 cartridge/pickup (1946) to the Integra A725 preamplifier (1970) to the P-303 / M-505 pre- & power amplifier combo (1977) to the TA-W800 cassette deck (1981) to the highly acclaimed M-510 power amplifier (1985), and so forth.

Onkyo’s achievements in speaker design are not minor. In the 1950s, Onkyo developed the then revolutionary non-pressed cone. In the 60's, MX-8P, the world's first motional feedback speaker, saw daylight. Since then, Onkyo has been producing numerous hi-fi-speakers worthy of the name, of which the high-end speaker system Grand Scepter GS-1 of 1984 is a good example. The problem is that, in Europe and North America, we know nothing about the vast selection of Onkyo speakers available is past decades.

It is true that in the recent past Onkyo has kept a low profile as a speaker manufacturer. With the D-302 E that has now changed, for D-302 E is not just one of those many impersonal boxes that keep filling the big shelves, being sold at half price three months after. No, the D-302 E is a remarkable attempt by Onkyo to raise small 2-way speakers to a new level of performance. This statement may sound pretentious and ponderous, but given the effort Onkyo has put into basing this speaker on brand new technical solutions, it is a fair statement.

When Onkyo claims to have designed this speaker from a clean slate, they mean mainly the drivers. Again, this statement is something understandable against Onkyo’s historical background. The drivers of the D-302 E aren’t from any existing driver catalogue. They are a result of Onkyo’s research team’s paying minute attention to every detail of the drivers’ performance. Here’s a brief selection. 

• New A-OMF diaphragm for better transient response

Regarding the 16 cm woofer, Onkyo’s most important design goal has been to retain piston motion throughout the audible range. Piston motion means, to borrow Gordon Holt’s definition of it, the ideal behaviour of the radiating surface of a loudspeaker diaphragm, in which the entire surface moves uniformly. According to Onkyo, conventional drivers feature a good deal of micro non-linerarities in how the diaphragm behaves during its displacement. This problem has been largely ignored, and must be attacked in various ways to obtain best performance. 

To achieve the aim, Onkyo has, among other things, carefully studied and chosen the diaphragm material. Or materials, really, because the diaphragm, although based on Onkyo’s own micro fiber (OMF) made from a pure cotton weave, is a three-layer construction in which OMF is first thickened with a polyethylene naphthalate layer (PEN) with a flexible cotton weave and finally with an aramid layer. This NEW A-OMF diaphragm covers the whole cone from the dust cup to the outer edge of suspension. It is said to have thickness 3 times and stiffness 27 times higher than the original OMF and with its many audible qualities.

• New V-Line edge and a die cast frame to prevent vibrations

A more rigid and flexible diaphragm certainly helps to achieve the perfect piston motion, but Onkyo has further improved it by the cone’s one-piece construction and with the V-shape suspension. V-shape is said to result in substantially less distortion than the traditional suspension shapes. The rigid die cast aluminum chassis of 6 to 20 mm thickness further prevents vibrations. It also helps the spider behave more ideally. 

•A large voice coil and a large ferrite magnet

A massive magnet of 140 mm diameter is used to drive the highly rigid diaphragm, the latter being mechanically connected to a large 65mm voice coil to achieve higher power handling. The obvious purpose of these measures is to enable the reproduction of the lowest octaves with adequate sensitivity and low distortion.

• Highly responsive ring-drive tweeter for high-frequency sounds

The same accurate piston operation range design policy is applied to the tweeter. Its ring shape diaphragm was reputedly designed with precision after numerous simulations. The 35mm voice coil is located between the inner and outer rings in order to distribute the energy equally. The tweeter also features an equalizer for improved transient response, and an aero acoustic drive to cut off high frequency interference. The tweeter is crossed 12 dB per octave at 2 kHz. The cross-over is in two parts and consists of seven high quality components.

• MDF cabinet

The wood-finished 15 litre cabinet (210 x 347 x 363 mm) is made of 30mm MDF. The front panel has rounded edges to minimize diffraction. A slit shape port is used that is mechanically separated from the enclosure to reduce undesired radiation noise.

The finish is excellent providing a feeling of a luxury item. The speaker comes with a grill, but, to be honest, I soon took it away, assuming that the difference in sound was insignificant. The speaker looks cuter and cooler with the woofer’s white cone openly visible.

This is one of those speakers which is capable of systematic and homogeneous presentation independently of the music with which it is fed. It handled all the records that I used for testing it in an admirably consistent manner. Let me give you an example.

Orchestral music from the Middle Ages performed with authentic instruments is the ultimate test material for choosing speakers. The timbres of the instruments are rich and often hard to reproduce. The sound in general can intensify up to nasty aggressiveness. No cottony-voiced crooners here. A speaker that passes the test must be revealing enough and retain the aggressiveness of the sound, and yet not make it unpleasant. Sufficiently competent all-round speakers frequently do well in this type of test, and so did Onkyo D-302 E.

To put in another way, universal speakers are speakers that do not make it necessary to keep the remote control of the CD-player or the amplifier within a grabbing distance, when moving from easy-to-reproduce music to painful-to-reproduce material either within an album or between albums. No such fear with D-302 E. 

The downside of this type of speakers is often a certain loss in liveliness and expressiveness. All speakers compromise something, but limited vividness is exactly the price that I’ve found almost all universal speakers have to pay. It is as if they could smile, but only inwardly.

To be sure, Onkyo D-302 E’s performance in this respect is not on par with the best wide bandwidth, single-driver crossover-less speakers. It had better not have been or I would have had to change my system. But it is not bad either. I have definitely heard universal speakers that compromise much more severely to accomplish the same goal of uniform presentation.

In fact, the sound of the Onkyo D-302 E possesses immediacy and speed almost unheard from this type of speaker. Most of the time I had a feeling that music did not overstay in the speaker’s mill a second longer than necessary. And the transients were superbly reproduced too. Obviously, Onkyo has succeeded in doing something right in this regard. 

Fast and vivid the sound is, but is it also non-colored and natural as Onkyo claims? My first impression of the subjective frequency response was that it was fairly smooth. No individual frequency range pops up or is unacceptably poorly represented with respect to others. Also, the transition from the woofer section to the tweeter’s range close to the crossover point did not offer any chances to complain about incoherence or irregularities.

My main criticism of its response is that the upper-middle range appeared a little lame, particularly in relation to certain accentuation in the HF region above. The audibility of this quality depended on music of course, vocal music being perhaps most vulnerable to it, but overall I wished that the speaker would have opened up a little, been more extroverted and less laid-back in its presentation. One upshot of this preference ordering was that the speaker sometimes hid small information in music that would have deserved to be better discernible; for example, non-harmonic noise from a string or bow.

Funnily enough, this property did not make the tonal balance non-neutral. More pleasant it was than many of the speakers with which I compared it, but never warm or rounded or anything of that sort. And the mid-range as a whole had extraordinary clarity and purity like the water in a mountain river.  

Onkyo claims that the speaker’s response goes down to 34 Hz (- 6 db?). In a bigger room I listened to it, I would say a half an octave higher. But what bass there was, was well justified and articulated. The speaker didn’t try to be anything else than it is, namely a fairly small speaker. And that is exactly as it should be.  

In a smaller room, things were different. All the bass apart from the bottom octave was there, allowing a wider range of music to be reproduced more realistically. But this time the bass was not entirely flawless. It was not boomy but a little pushy. In particular, if the volume was high, the bass showed a tendency to mask the mid-range slightly.

Just as with car engines, the performance of small two-way monitors depends on the system in which they are used. With an average sensitivity of 85 +/- 2 dB/W/m, D-302 E is not meant to be used with low-powered single-ended amps. Not that there would not be enough volume: that is a function of many variables. In my room, a 10 watt tube amp was more than adequate for my ears. The point is that power from 20 or 40 watts upward makes this speaker happier. The extra power makes it try its best. 

Officially these are 4 ohm speakers. Although I think the load is not that difficult, the owners of tube amps with 8 ohm nominal output impedance should check the compatibility of their amp with the speaker. My 15 watt 6V6 PP amp was a good match, but only when the watts were outputted from the output transformers’ 4 ohm tabs.

The speaker likes power but it liked tubes too. I tried two 200 W solid state workhorses (D-302 E’s promised max input power is 200 W). Their power was clearly perceptible in the sound but at the same time the sound was somehow murkier and less transparent than with the tube amps. These things are no doubt a matter of taste too, but the D-302 E is a sufficiently revealing speaker in order to be able to appreciate the values of the best tube amps.

I haven’t said anything about the speaker’s imaging potential and the sound stage so far because other properties are simply more important to me. Also, the spatial characteristics were what I expected them to be: the sound stays firmly between the speakers, left to right imaging being rather accurate. D-302 E does not have a particularly big sound.

Is Onkyo D-302 E a musical speaker? If being a musical speaker means possessing sonic properties that help to carry the listener closer to music’s message what ever that is, and contribute to musical satisfaction, then yes, D-302 E is a musical speaker. But it’s not a euphonic speaker. Its strategy is more subtle. It serves music by being a quick-moving reproducer, by having a pure and distortionless sound, and by exhibiting certain sonic sophistication and class not common to this type of speaker.

Onkyo D-302 E may not be a fantastic speaker but in many ways it is a fabulously good one. Had the sound been more effortless and open, and  just a little bit less opaque, it would have been almost perfect.