A traditionally niche category that has been seeing some increased visibility over the past few years is the class of home digital pianos that essentially represent the entry point to the high-end quality tier.
Roland's HP704 and Kawai's CN39 digital piano are two great examples of this type of instrument. Similarly priced and essentially geared towards the same end user, this is a comparison that many piano shoppers have been faced with.
With that in mind, we’re going to do a detailed comparison of the Roland HP704 vs Kawai CN39 by diving into their sound engines, speaker systems, actions and connectivity. These are both killer pianos, but one is likely to stand out over the other at the end of the day.
Roland HP704 vs Kawai CN39 - Digital Piano Sound Comparison
Digital Piano Sound - Sampling vs Modeling
When it comes to the sound engines, we’ve essentially got a comparison of the two types of approaches to digital piano sound process - sampling vs modelling.
The HP704’s SuperNATURAL piano sound engine is using modelling meaning piano tone is generated in real-time via a series of algorithms, while the CN39’s Progressive Harmonic Imaging is a sample-based engine built around an 88 individual note stereo sample of the Shigeru Kawai SK-EX concert grand piano.
Roland’s SuperNATURAL Piano Modelling Engine
When we first set up the HP704 out of the box and got playing, we felt there was a need to tweak the sound a little bit via Roland’s Piano Designer. Many modern digital pianos offer the user the ability to edit the character of the sound to their liking, and the HP700 series pianos are no different.
In this case, all we did was turn the brilliance down a little bit and adjusted the voicing, but the scope of parameters you can adjust here is vast and you won’t even necessarily need the owner’s manual for a tutorial - single note volume, single note tuning, single note character, key off-resonance, soundboard type, key off noise, hammer noise, full-scale string resonance, duplex scale, damper noise, damper resonance etc.
Kawai’s Progressive Harmonic Imaging (PHI) SK-EX Sampling
Kawai has the luxury of being able to record on the world’s finest concert grand pianos to use as the basis for their digital piano sound engines with the Shigeru Kawai SK-EX. Each note is recorded individually in stereo, and when the player presses a key, this sample is triggered.
You also have extensive control of the CN39’s sound via Kawai’s Virtual Technician feature which offers the user control of many of the same parameters as the HP704. We also tweaked the PHI engine by softening the low EQ for this review.
Check out the video to hear some side-by-side comparisons of the piano tone.
Polyphony Comparison
Both pianos are loaded in terms of polyphony - the CN39 has 256 notes on all tones which is very strong. The HP704 though manages to go even further with full limitless polyphony on the acoustic piano tones, and an almost unheard-of 384 notes on all non-acoustic piano tones.
Needless to say, you’re not likely to run out of polyphony on the CN39, and it would be virtually impossible to do so on the CN39.
Initial Sonic Observations
What are the big differences we’re hearing here? The lower register warmth coming off of the CN39 is quite a bit rounder than what the HP704 is producing. We’ve tried to edit them to minimize this difference, but it seems to be inherent to the sound engines.
For one, the SK-EX is just a really warm piano. There's so much lower range color that the SKEX emanates, and that’s been very nicely captured here. Dovetailing with this is a stronger sense of cabinet resonance that the CN39 is producing as well.
Speakers and Amplification
From a speaker standpoint, the CN39 has two down-facing main speakers and two upward-facing tweeters. The speakers, amps and signal processing were built in conjunction with Japanese audio company Onkyo.
The HP704 has a similarly configured powerful four-speaker system as well, however they are positioned so that the sound is more dispersed as opposed to directed right at your ear.
The total wattage on the HP704 is very robust at 60 watts, while the wattage is still good on the CN39 at 40 watts. The extra strength on the HP704 really becomes apparent in the mid-range with a deeper level of presence.
Roland spends an inordinate amount of time perfecting their speaker box designs, while Kawai’s emphasis is on signal processing. Despite two different areas of focus, we ultimately end up with two great sets of speakers here.
Different Tonal Experiences
After spending some time with both pianos, we would describe the overall sound of the CN39 as quite similar to a Steinway, while the HP704 more closely resembles the more intimate tone of a Bosendorfer.
If there was one weak link with many Roland digital pianos of the past, it was that the dynamic range always felt a little bit compressed. They've hugely improved on that in recent years, and the HP704 really attests to this as it's easy to get a nice intimate sound in the low volume range, and then totally dig in and get some power at higher volume levels.
That said, the CN39 still has a wider dynamic range overall, as well as in terms of the tonal variation that it's capable of.
Other Sounds - Electric Pianos and Organ Simulation
Once we move past the acoustic piano patches, the HP704 also uses a sample-based approach at this point so the differences between the two engines are not as pronounced. Both pianos are loaded in terms of quantity of sounds with 324 on the HP704 and 355 on the CN39.
The assortment of classic electric pianos is great on both, though we would have to give the nod to the HP704 overall in this category. On the other hand, when it comes to organ simulation, we feel like the CN39 has the HP704 beat pretty handily.
Pipe organs are another story, with the HP704 clearly the victor in this regard with some absolutely killer pipe organ patches.
Sonic Wrap-Up
Both pianos are delivering impressive sound engines and speaker systems to the mix. To our ears, the acoustic piano tone is warmer and has a wider dynamic and tonal range on the CN39, but the HP704 has a more powerful speaker system and thus a fuller sound with better acoustic projection.
And since we’re looking at two very different approaches to sound here, most people are going to listen to both side by side and instinctively have a preference.
Lastly, we should mention that both pianos have some added technology that enhances the experience when playing with headphones - Headphones 3D Ambience with the HP704, and Spatial Headphone Sound with the CN39.
Roland HP704 vs Kawai CN39 - Keyboard Action Comparison
Roland’s PHA-50 Keyboard Action
The HP704 is using Roland’s PHA-50 action while the CN39 is outfitted with Kawai’s Responsive Hammer III (RHIII) action. Both actions are found in several models throughout each manufacturer's product lineups and are highly regarded in the industry.
The PHA-50 features a longer key stick than the PHA4 action found in the HP702, and it uses a wood core to improve the dynamic resistance of the key. Roland products in general are known for durability, and the PHA50 certainly attests to this by being able to withstand some very intensive use.
There’s a stabilizer pin right at the very back of the key just like on an acoustic piano which helps with long-term stability, and it’s also nicely cushioned.
It boasts a triple sensor for accurate MIDI output, escapement and textured white and black keys that are a pleasure to play on.
Kawai’s Responsive Hammer III Action
The Kawai Responsive Hammer III action is entirely plastic based with no wood componentry, but otherwise specs out similar to the PHA-50 with a triple sensor, escapement and textured keytops.
This is the top plastic key action Kawai makes before jumping to wood-based actions, and is known for its excellent repetition speed and responsiveness.
It’s so well regarded that you can actually purchase an enhanced version of the Nord grand stage piano outfitted with the RHIII action instead of the basic Nord action it normally comes with.
How Do They Compare?
We generally find that the PHA-50 feels more natural when playing contemporary music where the dynamic range and finesse required are not as precise as what’s required when playing an exposed classic piece, for example.
The RHIII seems to offer more control in the lowest dynamic ranges - velocities that are quite difficult for digital piano actions to pull off. This is pretty consistent with Kawai actions in general, and as a result, it’s actually not as fun to play as the PHA50 if you’re playing pop or other contemporary styles.
The PHA-50 hits the bottom of the key bed a little bit harder than what you'd expect on a real acoustic piano, whereas this sensation is more true to an acoustic piano on the RHIII. There’s also a little bit more cushioning on the RHIII so it does feel like you can dig in a little bit more.
Digital Piano Action Wrap Up
We’ve undoubtedly got two solid and beloved key actions here. The wood that the PHA-50 keyboard is using is going to be viewed as an advantage since it improves the dynamic resistance of the key and the long-term durability.
The RHIII has an extra level of precision that will probably be greatly valued by those experienced with acoustic pianos and looking for a really solid practice action.
USB & Bluetooth Connectivity
Both of these pianos have a very solid stable of connectivity ports. For starters, both have discreet quarter-inch outputs, which means they’re both going to be totally appropriate for use in an institutional setting, or if you’re looking for a stationary digital piano for a church.
Both have USB recording and playback capability and USB to port connections, as well as both wireless Bluetooth MIDI for transmitting MIDI files and Bluetooth audio which essentially turns your musical instrument into a high-end audio system for listening to music.
You’ll want to check out Roland’s Piano Every Day app and Kawai’s PianoRemote apps via the Bluetooth MIDI connection.
They both have two headphone jacks, one-quarter inch, and one 3.5 mm, so you don't have to keep track of that adapter, and of course, a port for the AC adaptor power cord.
Aesthetic Considerations - Cabinet/Finishes
The Roland HP704 has a gorgeous cabinet and built-in piano stand that really looks the part of an acoustic upright piano - Roland’s cabinet design has been nothing short of stellar in recent years and a nice music rest for your sheet music and key cover caps it off.
It’s also available in a variety of finishes with their own SKU - Polished Ebony, Dark Rosewood, Charcoal Black and Light Oak. It’s also outfitted with Roland’s Progressive Damper Action Pedal with half-pedalling.
The Kawai CN39 also has a very nice cabinet, even if it’s not quite as substantial as the HP704. In terms of finishes, the CN39 is available in Satin Black, Premium Rosewood and Satin White.
The CN39 is equipped with Kawai’s Grand Feel Pedal System which also offers half-pedalling, and the spring tension is actually matched to an acoustic piano.
Final Thoughts
Either one of these instruments is a perfect option for a family or a person who knows that the piano plays a fairly important role in their life. Warranty coverage is great, and the fact that both pianos have the latest Bluetooth versions (Bluetooth ver 3 and 4) is also a nice touch.
Both pianos compare very well to some of the Yamaha Clavinova series instruments and would be a nice alternative practice instrument to an upright piano for a student, and even a serious player who for whatever reason needs to go digital as opposed to acoustic.
We hope this has been helpful!
