Heavenly Soundworks Five17

It has been just over 25 years since I reviewed the Quadrature Model 5, the first American DSP-based speaker (Issue 107) and declared it a revolution in the making. In the intervening two-and-a-half decades, the DSP revolution has indeed spread around in audio quite a lot, with digital room correction devices and digital EQ being widespread—really widespread. Roon, for example, offers DSP EQ as an option. And various devices have arrived to apply DSP processing to the signal in ways adapted to the speaker at hand—notably the remarkable Devialet SAM (Speaker Active Matching) system that I reviewed in Issue 293. And on occasion, speakers based on DSP have appeared, recent notable ones being the Dutch & Dutch 8c and the Kii Audio 3. Still, the appearance of a new DSP-based speaker remains relatively rare and something to take a special interest in.

Heavenly Soundworks is a newcomer on the high-end audio scene. It is a relatively small U.S.-based company, with the Five17 being its first product, but other, larger, and more expensive designs are in the works. The Five17 is a rather small speaker, but it offers impressive bass extension for its size as well as the claims of flat response and phase linearity that should come with the territory in DSP speakers. Its design approach is, however, quite different from the Dutch & Dutch and Kii 3, which focus on controlled directivity (involving narrowed dispersion in the higher frequencies). The Five17 pursues something else entirely—a wide pattern all the way from bottom to top.

The Speaker in Physical Terms and the Rationale for It

The Five17 is a three-way speaker, with a small (5″) bass driver supplemented by two 8″ passive radiators on the cabinet sides, a 3.5″ midrange driver, and 1″ tweeter. Tri-amplification is from a Hypex nCore Class D module and is internal to the speaker, and crossovers are done by DSP. The speakers will accept an analog input, converted to digital internally, but the design is really oriented towards digital operation. There is a remote control to set the volume level and choose the preset curves (discussed in the next section).

Heavenly is not revealing the source of its drivers, only that they have been carefully selected after experimenting with many possibilities. It is also closed-mouthed about its crossover design. But the composite effect of the small drivers, especially the midrange, would be expected to be an unusually wide radiation pattern. And this actually happens, on the whole. In the NRC measurements I’ve seen, the level at 45 degrees off-axis at 2kHz is practically the same as the on-axis level, and even at 75 degrees off-axis it is down only around 5dB. This is quite different behavior from, say, the Dutch & Dutch 8C, which is down about 10dB from its 200Hz level at 3kHz at 75 degrees off-axis, and at only 45 degrees is down 5dB from its 200Hz level. In the Dutch & Dutch, DSP is being used for something else; the difference in the Heavenly is quite deliberate. Heavenly’s people, the father and son team of Kevin and Jonathan Couch (Kevin does the audio engineering, Jonathan the industrial design), firmly believe in this business of wide pattern. 

Volume Compensation

A striking option is available in the Five17: Fletcher-Munson compensation for reduced listening level. This involves boosting the bass to offset the fact that as volume is reduced the perceived loudness of low frequencies drops faster than the perceived drop in the midrange. Quite a large boost is implemented in the Five17, amounting to over 5dB at 50Hz on one setting, and I estimate another 3dB or so on the more extreme setting (on the remote these are labeled F2 and F3, with F1 being the “neutral setting”). Which of these works best will depend on level, room, and, of course, recording.

It turned out that this was quite useful in my experience. I used setting F2 a lot. The actual level of live orchestral music at close range (where recordings are made) is not astronomical, but it is somewhat higher than most home listening rooms comfortably accommodate, and the result is that some extra bass energy can be very useful if you are not blasting away but are intent on hearing a natural balance. 

In a concert hall, the sound at distance has extra bass because a good concert hall lifts the bass in the reverberant field more than it does higher frequencies, and the fraction of the sound that is reverberant field is higher at increased distance. For the same reason, highs are reduced at a distance. So, the bass-lifting kind of compensation makes sense, even at the levels corresponding to live sound at a certain distance. In any case, it is a useful thing to have available. It is worth noticing in this connection that the “target curves” of DSP room correction devices are often recommended to be elevated in the bass somewhat. A complex set of issues is involved here, but in any case, I found the presets provided in the Five17 desirable. Of course, one could do this by the also-available user-controllable EQ (to be discussed below), but it is very convenient to have this instantly available on the remote control. 

Measurements and History 

The measurements on the website for Heavenly Soundworks show very flat and smooth response. This is one of the things that got me interested in the Five17s in the first place. But there is a slightly convoluted history here.

The NRC measurements on the early version of the speaker looked rather bumpy. But Heavenly discovered that there were errors in the measurements of their own that they used to set the response of the speaker, this being easily controlled in a DSP speaker. This was corrected, and the speaker now really is smooth and flat. You can read this story in detail at heavenlysoundworks.com/post/in-pursuit-of-perfection. If you are interested in measurements, you should check this out.

Meanwhile, my own measurements on the current, presumably final version show flatter and smoother response than most speakers—with one exception. The upper frequencies are elevated, smoothly but definitely. And this counts audibly. You really need to shelve the treble down to get natural balance. The speaker sounds somewhat midrange-recessed because of these elevated highs, an effect emphasized by the fact that the area around 500–1000Hz is down in level off-axis compared to around 3kHz. More on this point later.

The Built-in EQ 

The balance of the Five17 is adjustable. Part of the Hypex amplification internal to the Five17 is EQ adjustment, which you can do via computer and then store in the Five17s themselves, so you do not need to leave the computer attached. This is useful—indeed, it is really important, since otherwise the combination of the rising response on-axis and the wide pattern results in a top-end orientation, which is not really what you want for the vast bulk of recordings. The EQ is easily done—and shown on the computer screen before you install it. It would be awkward to change this to fit each recording, though you could. But it is easy to install once and for all, and indeed one can install three settings on the remote control, which would enable quick change to match a given recording. This is a good feature to have, and you should check it out. It is not heavily emphasized in the owner’s manual, but it is well worth looking into. 

The Sound of the Speakers, When Set Just Right

To some extent, when a speaker has built in EQ—not just level controls on the drivers like those of the old days (the AR3, for example), but actual EQ in detail—reviewing it is talking about a moving target. You can get in there and change the sound a lot. In a sense, you become a participant in the design process. Most speaker reviews amount in good part to a more or less poetic description of what the response of the speaker does to music. Even things like depth of image and so on, many things which do not seem to be a matter of frequency response at first sight, actually are in good part. So, when one encounters a speaker where the response is adjustable, one must think of the review process in a new way. 

Of course, nowadays, external DSP EQ makes every speaker adjustable in this sense. The real question about a speaker today is not only how good it sounds, but also how good you can make it sound with such adjustments. Of course, not everything can be changed by such adjustment.

This comes to mind especially with the Five17 since the EQ is built in, even though you can, of course, leave it in its default position. The default position was not, however, in my experience the way to make the speaker sound as good as it can sound. As noted, pulling the top down a few dBs makes the sound better. But it does not make the Heavenly sound exactly like other speakers. Factors other than EQ settings are always involved and reducing the treble level in a wide dispersion speaker does not create the same sound as it does in a speaker with increasing directivity as frequency increases. (Too bad—if nothing counted except on-axis response, one could DSP to make anything sound like anything else. But, of course, this does not quite happen.)

In the Five17s, as with any speaker, there is a kind of ineradicable character which remains even if you make the speaker completely flat in direct arrival. This character, which exists for any speaker but varies from speaker design to speaker design, is in this case derived, I think, from the fact that the far-off-axis response is a bit pushed down in the 750–1500Hz octave, or so I estimate, compared to below and somewhat above that. The really high treble rolls off off-axis, which is true for almost all speakers and is desirable. But the Five17 rolls down in the 750-1500Hz range, while minimally doing so in the octave from 1500–3000Hz. Now, many speakers have some dip over a range of frequencies, but it is often further up in the spectrum. BBC-style two-ways, for example, tend to have a dip off-axis around 3–4kHz and a return to flat at 5kHz. This has a considerably different sonic effect.

In the Five17, if you make it totally flat on-axis—which it is not all that far from being in its default EQ setting, except for that small, general top-end rise—the midrange sounds suppressed somewhat, and the image is recessed, in particular. Whether or not I am correct in my explanation of this, the sound is definitely there as described.

Now, this is not at all unpleasant in many cases. Lots of recordings can afford to be pulled back in this way, and, especially at not too high volume levels, the effect can be pleasant. Sometimes, it is beyond pleasant and verges on the magical. The depth of image can be hypnotic. But the sound is skating somewhat too close for comfort to too much 3kHz and thereabouts, which is not always a desirable effect depending on material.

How Good Can You Make Them Sound?

As noted, you can change the sound with the built-in EQ. This is easy. One downloads a program online, then attaches a computer via a suitable USB cable, and then adjust the speaker’s response (doing each channel separately, but you can copy the setting you come up with on one speaker and transfer it to the other so that they remain pair-matched). This is easy to do. But deciding on the best EQ requires some experimenting. The idea is that you want to add just a little to the part of the range—750–1000Hz, say—that is down off-axis and subtract a little from the region around 2–3kHz that is up in level off-axis, to get a neutral perceived balance. 

The question, of course, arises whether this is possible. The direct arrival and the off-axis sound bouncing off the walls are not controllable by EQ independently. So, there really is a question. In extreme cases of wild off-axis behavior, the answer would be no, you can’t fix it. With the Five17s, which are smooth off-axis, I found that you could make a real improvement by this kind of EQ compensation. Nothing extreme or abrupt should be done, but you can get rid of the sense of pushed-back mids and excess presence to a good extent. Not completely I found—although I may not have worked hard enough. 

Since the early reflections and the direct sound are pretty much lumped together perceptually, it makes sense that some compensation is possible. But probably you cannot expect the compensation to be totally successful.

In practice, working with the built-in EQ I got something that sounded “good,” smooth, and quite neutrally balanced to my ears. But it took experimentation. In effect, you are doing a bit of speaker design for yourself here. And the amount and kind of EQ needed was room dependent. 

I tried the Five17s in two rooms quite different from each other acoustically. What needed to be done was different in the two.

Properly adjusted, the Five17s sound very musical, smooth, clean, and invisible as sources, too. But they always have a distinctive character associated to their radiation pattern. Of course, in a sense, all speakers do. But the directional behavior of the Five17s is unusual in its nature. 

In other directions, the Five17 performs well. The bass is surprisingly extended for a speaker of its size, though you cannot really crank it with bass-heavy material in a large room without running up against limits. The speaker is, as I understand it, protected from damage, but really high levels start to make it sound compressed and a bit distorted in bass-heavy material—not that this was an issue for me in the relatively small rooms I was using and at the natural (not-too-high) levels I prefer. But the Five17s are designed it seems for rooms of small to moderate size—if you want to fill a ballroom, Heavenly has larger models in the works that are considerably more expensive.

Overall

Putting all this together was a fascinating experience. Getting the EQ tweaked out just right took some time, but the result was impressive in many respects. The depth of image was very lifelike, and aspects of the music emerged that might have passed unnoticed with other speakers. To take a random example, the Telarc recording of the Debussy and Ravel string quartets played by the Cleveland Quartet (an Aubort/Nickrenz recording masterpiece) had a realistic ring to the pizzicato in the second movement of the Ravel, which is seldom heard in music reproduced by speakers, a kind of subtle sonic spectacular in a context—a string quartet recording—where spectacle is not really expected. 

Or take the Centaur CD of the late William Parker singing Copland’s Old American Songs. Word clarity was perfect; the animal sounds of “I bought me a cat” were startlingly vivid. Parker is sadly no longer with us, but his marvelous singing lives on. 

The fabulous Rimsky-Korsakov Scheherazade recorded by Aubort/Nickrenz—with the St. Louis Symphony, Semkov conducting, in Powell Hall—was too recessed and unnaturally edgy with the default EQ, but with the right user-chosen EQ setting it sounded very convincingly like the sound one hears in Powell (to the extent I can remember—it has been a while) and, in any case, sounded very natural and like an orchestra in concert in a good, or in this case, super-good venue. 

Note in this connection that the Five17s need to be listened to on a lower axis than might arise if you are close to them sitting on a chair of regular height. The stands supplied and, indeed, the speakers themselves look elegant, but the stands really ought to be higher. You could put the stands on pedestals—they are flat bottomed and would be stable placed on say an eight-inch-thick slab of some sort. Getting on the correct axis makes a considerable difference. Sitting above the ideal axis, the sound is just too recessed.

In sum, I had an intriguing time with the Five17s. There are a lot of interesting thoughts here. And if it takes some doing to end up with the best results, still the best results are good ones. Their sound is unusual but unusually good in a certain way. The difference between the Five17s and something like the KEF Reference 3s that I had around for my Devialet SAM system review is large, the KEFs being rolled off-axis starting at 500Hz on up (exactly what a speaker ought to be doing off-axis—or even on). 

As designers get more control over frequency response and radiation pattern, it becomes more and more clear that they are not all aiming at the same thing. This situation makes it even more important that one listens carefully for oneself. No one else can walk that path for you, of trying to decide what you want your speakers to do. The Five17s present a distinctive view and a definite philosophy of how a loudspeaker should behave. It is surely worth checking them out—there is not much else around like them, since most DSP designers are going via the narrow-pattern controlled-directivity route and for a slight, or not so slight, downslope in on-axis response. The Five17s do neither of those things but present a different view of neutral sound, and one which can be convincing, indeed. Your choice. What they do, they do very well, and in a remarkably small and elegant package. 

Specs & Pricing

System: Three-way active (tri-amped) speakers, with remote volume control and response presets (three)
Driver complement: 1″ tweeter, 3½” midrange, 5″ woofer, two 8″ side-firing passive radiators per speaker
Frequency response: ±1dB 30Hz–20kHz, –3dB at 27Hz, –6dB at 24Hz
Inputs: AES/EBU digital, SPDIF digital, TosLink, plus analog input (internal A-to-D conversion), balanced XLR, unbalanced RCA
Internal amplifier power: 100W tweeter, 125W (bass), 125W (midrange) (Hypex modules)
Max output level: 108dB continuous @1m, music source
Dimensions: 8.5″ x 15.25″ x 11.5″
Weight: 24 lbs. each
Price: $10,000/pr.

Heavenly Soundworks, Inc.
heavenlysoundworks.com
info@heavenlysoundworks.com