Ocean Way HR5

Ocean Way’s newest studio speakers bring the sound of ’70s horn‑loaded mains to the nearfield monitor format.

Who says all nearfield monitors are the same? The subject of this review is the Ocean Way HR5 active nearfield monitor and it’s very much not run‑of‑the‑mill, either in terms of its appearance or electro‑acoustic design. It’s an unusual one there is no doubt. Before I get on to why the HR5 looks the way it does, and what that means, perhaps a little Ocean Way background would be appropriate.

The Ocean Way name has been around in pro audio since the mid‑1970s, when teenage musician and audio enthusiast Allen Sides began building speakers and recording bands in a rented garage in Los Angeles. Sides named his business Ocean Way after the street in which the garage was located. Outgrowing the garage, Sides rented space at the United Western Recorders studio on Sunset Boulevard, where his recording and speaker‑building business then grew to such an extent that in 1988 he was able to buy the entire studio, and rename it Ocean Way. The Ocean Way studio group grew to four high‑end complexes (Hollywood, Sherman Oaks, St Barths and Nashville), for which Sides designed all the main monitoring, before it was sold in 2013. Sides’ Ocean Way business now manufactures a range of both pro‑audio monitors and high‑end hi‑fi speakers.

The HR5 is the latest and the most compact in the Ocean Way range to employ the same horn‑loading techniques as the company’s main monitors. It’s also the only fully horn‑loaded monitor of nearfield proportions that I’m aware of (although at 31 x 45 x 37 cm and weighing just over 17kg, it’s a relatively big and heavy nearfield monitor).

Within the cabinet, all but hidden behind its complex, multi‑profile horns, are an 18cm bass/mid driver and a 25mm soft‑dome tweeter. Substantially obscured as they are, it’s not easy to discern much concerning the drivers’ construction. Around the back of the cabinet is an amplifier heatsink and connection panel, and an unflared circular reflex port. The choice of an unflared port will lower the volume level at which the airflow will become turbulent, with port compression and distortion effects becoming apparent at lower volume levels than they otherwise would.

The HR5 amplification offers balanced XLR analogue and AES3 digital inputs, an AES3 output, input sensitivity adjustment and four configuration LEDs that illuminate in conjunction with a pinhole button. Pressing this button cycles through configuration options for input selection, digital input left or right channel assignment, and an 85Hz roll‑off option for use when the HR5 is partnered with a subwoofer (the Ocean Way S10A is advertised as a suitable option). Different LEDs illuminate depending on the configuration selected. In terms of power ratings, the HR5’s ICEpower Class‑D amplification offers a reasonably generous 125 Watts for the bass/mid driver and 90 Watts for the tweeter.

So, behind the plane of the drivers, the HR5 is actually a relatively conventional two‑way compact ported speaker. The compression horns located in front of the drivers obviously mark it out as a little different, however, so I’ll spend a paragraph or two attempting to get our collective heads around the fundamentals of horn‑loaded speakers.

The HR5 can claim a direct lineage back to West Coast rock & roll history... even I couldn’t resist playing ‘Hotel California’ for the first time in many decades.

Sounding The Horn

Back in the days before transistors, and certainly before Class‑D amplifiers made high audio power levels so easily accessible, relatively low‑power valve amplifiers were the only option and, as a result, speaker efficiency (electrical power in against acoustic power out) was at a premium. Even now, typical ‘naked’ bass/mid drivers struggle to achieve single‑figure efficiency. And that’s where horn loading initially came in. By increasing the effective efficiency of moving‑coil drivers, horn loading made possible the public address systems in movie theatres and live music venues, and the high volume levels required of main monitors in recording studios. It was only the arrival of transistor power that began to make horns unnecessary.

But how, I hear you ask, does a horn increase efficiency? It’s all about radiation impedance. When a naked driver diaphragm moves in a fluid (air, for instance), the power it transfers depends on the fluid’s density. A big difference between the density of the diaphragm and the density of the fluid is equivalent to an impedance mismatch in an electrical circuit. Imagine trying to power yourself along by doing a front crawl swimming stroke in air rather than in water. It doesn’t work in air because air is very much less dense than water. The higher density of water stops the molecules from moving sideways to get out of the way of your gracefully sweeping hands. Fish can move rapidly in the water with small fins, while birds need big wings to stay in the air, all for the same reason.

Adding a horn to the front of a speaker works because, down at the business end, otherwise known as the throat, the horn essentially stops the air moving sideways and getting out of the way of the diaphragm. The length and flare of the horn then progressively blend the radiation impedance at the throat into that of free air. The principle is pretty simple, however, as with many simple principles, if you dig a little deeper it gets complicated. The complications arise mostly because we live in a universe in which the laws of physics dictate that the most effective way of transitioning from the throat to an exit in the listening space requires horns many metres long (and consequently many metres in height and width). Usable horns have to end at some practical length, however, and that both puts a limit on the lowest frequency at which they will work, and results in resonant standing waves being set up along their length. Above the cutoff frequency, a series of peaks and troughs in the frequency response arise as a consequence of the standing waves. It’s these resonant response anomalies that are often responsible for horn‑loaded speakers having a reputation for a characteristic subjective quality.

The shape of the horn as it expands away from the throat is also critical, and while the simplest geometry (a straight‑sided cone) can work, the efficiency gain it provides is minimal at lower frequencies. Exponentially expanding horns can provide suitably increased efficiency gain at lower frequencies, but also demonstrate a ‘cliff‑edge’ low‑frequency‑cutoff.

To these complications of horn length, mouth size, flare rate and flare shape, you can also add the potential extra efficiency gains provided by a ‘compression’ design, where the cross‑sectional area of the throat is significantly smaller than that of the driver diaphragm. Non‑symmetrical arrangements, of the type employed by the HR5, where dissimilar lateral and vertical flare and length are also an option. Clearly, when you decide to design a horn‑loaded speaker, there’s an awful lot of parameters to juggle.

If that were not enough, along with the efficiency gain that results from horn loading, you also get some control of dispersion. With a naked driver, dispersion is fundamentally defined by the size of the diaphragm, but with a horn, dispersion is defined by the size of the mouth and the angle of flare. Ocean Way, in their marketing material, advertise that the HR5 horizontal dispersion extends to ±50 degrees, a number that roughly approximates the average horizontal flare angle of its horns. Now, ±50 degrees is quite an ambitious claim, but no limits were provided, so we don’t know if that’s ‑0dB, ‑3dB or ‑XdB of the axial frequency response, or over what bandwidth. It’ll be interesting to take some FuzzMeasure data and see. As far as vertical dispersion is concerned, Ocean Way claim ±20 degrees, but again, this is without the benefit of any limits.

Returning to the horn‑loading efficiency gain for a moment, the reason that it is potentially of benefit in a nearfield monitor is that it means the drivers have to work far less hard to generate the necessary volume levels than they would in a direct radiating design. All other things being equal (warning: all other things are rarely equal!), this should result in lower levels of distortion and thermal compression, and an ability to play louder. There is one fly in that ointment, however: thanks to the HR5’s bass/mid horn being relatively small, its cutoff is around 150 to 200 Hz, and below that frequency the system will tend to behave more like a conventional direct radiator. This means that it’s potentially the low‑mid/bass band, rather than the higher‑frequency horn‑assisted band, that will define the HR5’s maximum volume limits and distortion behaviour.

Measuring Up

So, to some Fuzzmeasure data. Diagram 1 shows an axial frequency response of the HR5 from 300Hz to 20kHz. The measuring mic was 60cm distant and aligned vertically with the lip between the HR5’s two horns.

Diagram 1: The orange and green traces show the frequency response matching between two HR5 speakers. Matching is better than ±1dB across their entire bandwidth.

The first thing to note is that actually there are two curves in Diagram 1, one for each of the pair of monitors. Ocean Way claim in the HR5 marketing material to achieve better than ±1dB left/right pair matching, but based on Diagram 1 they actually do rather better than that, which is admirable. The second thing to note is the gentle ‘dipped’ character of the response shape, with the minimum centred at just above 5kHz. This measured response shape confirms some comments Ocean Way made to me about how the HR5’s frequency response is voiced for the most useful real‑world balance.

The last thing to note about the HR5’s axial response is that, although the average trend is admirably flat (intentional balance tweaks aside), it’s relatively uneven. This suggests there’s multiple minor diffraction and standing‑wave phenomena at play throughout the bandwidth.

Diagram 2: The response of the HR5, on‑axis (green) and 50 degrees horizontally off‑axis (blue).

Diagram 2 shows a repeat of the axial response of Diagram 1 overlaid with a response taken at 50 degrees off‑axis horizontally. From 300Hz to 12kHz the HR5 is around ‑6dB at 50 degrees. Below 300Hz, as is the case with most similarly sized monitors, the HR5’s dispersion tends towards omnidirectional, and above 12kHz some horn standing wave or diffraction effects impose a couple of sharp response anomalies. In the grand scheme of things however, the HR5’s horizontal off‑axis response is impressive. There are few conventional, direct‑radiating monitors that achieve anything like linear and well controlled dispersion, especially through the midrange, right out to 50 degrees. Finally on horizontal dispersion, the HR5 response anomalies above 12kHz may look significant but I’d expect them to be relatively benign in practical terms.

The Ocean Way argument in favour of wide horizontal dispersion is that it helps ensure multiple listeners hear the same tonal balance, and that the stereo ‘sweet spot’ is expanded. I’m personally not entirely convinced by these arguments. Firstly, nearfield monitoring tends to be, almost by definition, a one‑person job, and secondly there’s a psycho‑acoustic argument that, especially when speakers are used in smaller rooms, directing significant wide‑bandwidth audio out sideways to reflect from the side walls does no favours. It will drive the room acoustics harder and bring the reverberant field closer to the nearfield. The extended stereo sweet spot argument is also, to my mind, a little superficial because the perception of stereo is dominated by inter‑aural arrival times and not by differences in volume level. Certainly, wider horizontal dispersion will mean that multiple listeners are more likely to perceive a similar tonal balance, but I’m not convinced it can significantly improve stereo imaging (other than by making it less explicit through placing listeners in the reverberant field) at a non‑central listening position.

Diagram 3: The HR5’s vertical dispersion characteristics. The red, green and blue traces show, respectively, the on‑axis, 20 degrees above, and 20 degrees below‑axis responses.

Moving on to vertical dispersion, the Ocean Way claim is ±20 degrees, although again that’s without any defining limits. Diagram 3 illustrates what I measured. At 20 degrees upwards, the HR5 again shows well‑managed dispersion that’s generally within about 4dB of the reference axial response. However, 20 degrees below shows a significant dip around 1.5kHz (the output above about 5kHz is also attenuated slightly but that’s partly a result of the increased distance between tweeter and measuring mic). The dip is almost certainly a result of phase cancellation between the two drivers in the crossover region, where their outputs overlap. A phase cancellation dip in one vertical off‑axis direction is very common in multiway speakers, so the HR5 is by no means alone in displaying such a phenomenon, however the relatively low crossover frequency of the HR5 puts the dip at a sensitive point in the bandwidth and I’d expect the dip to be audible. Having said that though, I guess listening to the HR5 from a below‑axis position is unlikely.

Diagram 4: The HR5’s LF response, measured at the lower horn.

Diagram 4, the last FuzzMeasure curve before I get to describing my subjective feelings about the HR5, shows a frequency response obtained by placing the measuring mic on the central axis about halfway ‘down’ the HR5’s low/mid driver horn. There’s no particularly definitive data to be gleaned from Diagram 4, however I’ve included it for interest because its uneven nature perhaps illustrates the horn standing wave phenomena I mentioned earlier and how they introduce resonant dips and bumps. For example, I wonder if the sharp feature just below 200Hz is evidence of the horn cutoff? In any event, a naked driver in a baffle measured with a microphone at a similar distance would almost certainly display far greater evenness of frequency response.

Listening In

I listened to the HR5 in my usual setup with the monitors around 1.5m apart, mounted at seated head height on extremely rigid wall brackets. As usual, the diet was a variety of Pro Tools mix sessions and well‑known tracks ripped from CD. The first thing to note was a slightly disappointing audible level of hum and hiss. We give active nearfield monitors a very hard time in terms of amplifier noise through listening so close, and the HR5’s noise isn’t a deal breaker (and it’s by no means the worst I’ve heard) because it becomes effectively inaudible once music is playing. However, it is audible in the gaps and slightly distracting when nothing is playing.

Moving on to playing some music, the HR5’s fundamental tonal balance immediately sounded well judged and to my ears right on the money. I’d have few worries making mix or mastering judgements on overall balance and I’d expect mixes to translate well in those terms.

The second characteristic of the HR5 that I established pretty quickly is that, while it demonstrates good subjective tonal consistency horizontally, it’s not so strong vertically. The 1.5kHz dip at 20 degrees below axis was audible and I had to be careful with my posture while listening. If I slouched and let my head drop too far there was a noticeable tonal change; voices in particular became somewhat recessed and dull. Vertical dispersion upwards however was far more consistent and reliable.

...the HR5’s fundamental tonal balance immediately sounded well judged and to my ears right on the money. I’d have few worries making mix or mastering judgements on overall balance and I’d expect mixes to translate well in those terms.

So the HR5 scores well subjectively in terms of overall balance and horizontal dispersion, and it displays the dynamic, explicit character I’d expect of a horn‑loaded monitor, with apparently no practical limit on loudness (I gave up before it did). If you regularly monitor at high levels, the HR5 will be of interest. Similarly, despite its unflared port design, I didn’t have many issues with the way the HR5 plays bass. Subjectively, it didn’t seem quite as extended in terms of bandwidth as its 45Hz specification would suggest, and I suspect a good closed‑box monitor would offer more in the way of low‑frequency detail, pitch security and timing, but the HR5 bass was relatively free of ported speaker flaws and the overall bass level was well judged.

Almost all monitors are of course a mixed bag, and along with its positives the HR5 displays a couple of subjective negatives for me: the way it presents mix detail, and some coloration on voices. In the first case, I never quite got the feeling that I was able to hear really deeply into a mix. Some mix elements appeared a little veiled: plug‑in effects, for example, sometimes seemed a harder to judge than I’d like. Stereo image focus and depth also appeared less explicit than I’d expected, and the sense that some monitors provide, of all the components of a mix individually laid out for inspection, wasn’t quite there for me with the HR5. And in the second case, I often use simple voice recordings when appraising monitors and with the HR5 I felt the balance between vowel and consonant elements was slightly awry, with the former suppressed and the latter, especially sibilance, exaggerated. Female voices in particular also occasionally took on a mild nasal character, and cymbals sometimes sounded a little thick.

Despite all that, the HR5 has much to recommend it: its roots are firmly in traditional, horn‑loaded American studio monitoring, and it undoubtedly looks very cool, but more than that, the HR5 can claim a direct lineage back to West Coast rock & roll history. I can absolutely see that for some users this will all be enough, and even I couldn’t resist playing ‘Hotel California’ for the first time in many decades (and, for the record, I don’t mind admitting I loved it). To my mind, while the HR5 is perhaps not an ideal monitor for acoustic folk, jazz or traditional classical genres, if I were working in EDM, guitar‑based indie or commercial pop production, for example, its wide bandwidth, dynamic nature, well‑judged tonal balance and ability to play loud without changing character or showing any signs of strain might well be exactly what’s needed.

Monitoring is, of course, a personal decision and my opinion just one among many. That the HR5 didn’t entirely deliver for me doesn’t mean it won’t for you. If I were in the monitor market at the HR5’s price and wanted to try something a bit leftfield as a contrast to all those conventional active two‑way boxes, the HR5 would be a perfect fit.