Review: Roland HPi-5 Digital Piano

he distinguishing feature of the Roland HPi-5 digital piano is a small monochrome LCD monitor in the music stand rather than behind the keyboard as in many other digital pianos. The LCD displays the menu selections and has a primitive "score screen" that is supposed to be able to display music electronically. The music stand is therefore a good place for it, and it can be easily covered up by putting sheet music in front of it. It can also be turned off. Unlike with some other models, the LCD cannot be replaced by an external computer monitor. The LCD screen is too small to be useful for displaying music, but is necessary for displaying the menu choices. For example, in order to change the voice or reverberation level, it is sometimes necessary to press the cursor button numerous times. With over 400 voices, a visual display is essential.

The HPi-5 has 64-note polyphony, which is a compromise, although not a serious one. However, an annoying side effect is that the decay rate on the piano is too fast. With the sustain pedal depressed, the lowest note on the keyboard becomes inaudible after only 24 seconds. This is much shorter than with an acoustic piano.

Unlike the portable RD-700, the HPi-5 is difficult for one person to carry up the stairs, since it weighs over 147 pounds (67 kg) and is a bit awkward. However, it can be done.

The Sympathetic Resonance feature has been greatly improved over earlier models. In earlier models, setting the resonance to a high level made a very unpleasant and even painful sound. However, it's still not the true sympathetic resonance that you would get on a real piano. For one thing, although the resonating sound is no longer identical for all keys, depressing a second key still doesn't change the resonance sound. The piano also makes a mechanical clunking sound when you depress a key, similar to a real piano. Unlike the Yamaha Clavinova, however, there is no corresponding "off" sound when the key is released.

Sound samples

Upon playing the Roland HPi-5, it immediately becomes obvious that the digital sampling is different from other Roland pianos like the RD-700 and RD-150. When listening to Grand Piano-1 sounds from the HPi-5 using headphones, the midrange keys have more of a booming sound as if the microphone had been placed very close to the soundboard. Although this takes some getting used to, the sound is definitely superior to the Grand Piano 1 sound in the Roland RD-150 and 700. The old sounds are also included in one of the menus. One reason for the new sound samples may be that the unit was designed with enclosed 6-inch speakers that point down toward the ground, and the sound is supposed to bounce off the back of the piano, which is a sheet of 1/2-inch thick compressed fiberboard. This means that, unless you have good quality headphones, the HPi-5 sounds much better through the speakers than through headphones. However, the speakers are too small to reproduce the fundamental harmonic of the lowest half-octave. This is a particular problem for the organ sounds. One solution would be to use a good quality set of headphones such as the Sony MDR-7506 or Sennheiser HD590. Good headphones are even more essential for the organ sounds, which sound muddled and dull through ordinary phones.

The HPi-5 has an alternative grand piano sound ('Grand Piano 2') which is much thinner and brighter than the main piano sound, and sounds more like a typical Yamaha than the Steinway that Grand Piano 1 is sampled from. Unfortunately, the Grand Piano 2 is slightly out of tune. Trying to play the Roland HPi-5 set to Grand Piano 2 was like trying to play a chalkboard with your fingernails. (For people too young to know what fingernails dragged across a chalkboard sounds like, just imagine the acoustical equivalent of "Carrot Top").

Unlike the Grand Piano 1 samples, the other piano sounds (Upright, etc.) are sampled in monophonic sound. Unlike Grand Piano 2, they are in tune. These other voices have more "color" than the flawless Grand Piano 1 sounds.

The HPi-5 also has a number of non-piano sounds (421 in all including variations), some of which were digitally sampled, including violin, guitar, banjo, koto, and has a variety of church organs (including some "detuned" organs) as well as some weird percussion noises and sound effects. Some of these sounds are, indeed, vaguely reminiscent of the original instrument, but there is no flexibility in tailoring the sounds. For example, voices like the violin, trumpet and flute have a fixed vibrato. Purists may object to using these voices, but some Bach actually sounds pretty good in the flute setting. However, the attack and decay rates also can't be changed. The inability to tailor the sound is especially problematic for the organ sounds, because organ players are used to tweaking things in order to get a good sound. Some of the sound effects, like 'explosion', 'thunder', and 'barking dog' may be important if you have children who are learning the piano, because it helps maintain their interest. Otherwise, they are unlikely to ever be used. There is no way to digitize sounds from a microphone.

You can only adjust the overall tuning (from A = 415.3 to 466.2), but not individual notes, although you can switch among 8 different temperaments. Settings are lost when the piano is turned off. It has a sostenuto pedal, and the damper pedal has half-pedaling.

In earlier Rolands, the sound quality was sometimes markedly degraded when returning to piano after using some of the other sounds such as organ. It was necessary to reboot the piano to prevent the piano sound from being muddled by this apparent software problem. This seems to be fixed in the HPi5.

Keyboard

Like most digital pianos, the plastic keys sometimes feel too slippery. Piano keys become slippery when your fingers are too wet or too dry. One solution is to pour some regular (not diet) Fanta Orange Soda in a dish and coat your fingertips with it. Any other soft drink with high fructose corn syrup also works. Another trick is to use a finger cot or to put a very small amount of vitamin E on the fingers.

The keyboard on this piano is also fairly stiff. It takes 70 grams to press a key, compared with 45-50 for a normal piano. This means playing this thing becomes exhausting after a while. The weighting is the same for all the keys.

The action uses Roland's Progressive Hammer Action keyboard, but unlike the more expensive models, doesn't use an escapement. The escapement in the high-end models makes the feel more realistic. However, the Roland keyboard doesn't use springs and is not too bad. The keyboard has three touch sensitivity settings (heavy, medium, and light). These settings have no effect on the pressure required to depress the keys themselves, but change the loudness produced by a keypress. In piano mode, pressing the keys harder not only changes the loudness, but also produces more higher-frequency harmonics, making the sound brighter. This is similar to the effect on an acoustic piano.

Computer interface

The HPi-5 also has a floppy drive and a Midi port, but no USB port. You need to buy a USB-Midi interface cable to connect to a USB port. It also has the feature, found in high-end pianos, of automatically creating a score when you play something new. However, the monitor has far too low resolution (320x240) to display it adequately, and the processor is a bit slow. Many digital pianos have features such as an artificial intelligence feature that listens to a microphone, figures out what key you are trying to sing in, and automatically plays a karaoke-style piano accompaniment. This is mercifully absent in the HPi-5. Some of the other features found in other pianos, like Yamaha's infamous blinking lights behind each key, are also absent. However, there are a large number of schmaltzy tunes prerecorded in the piano, and it is difficult to avoid accidentally playing them if you hit the wrong button. A good whack to the 'off' switch is the best way to stop this.

Update (March 4, 2007)

Using a digital piano with an equalizer: The sound can be improved slightly by connecting an audio equalizer to the two two-conductor audio output phone jacks in the back. Modern-day equalizers can do more than emphasize various frequencies. They use Fourier transforms and digital technology to add reverb, adjust the stereo separation and dynamic range, and many other parameters. However, unless you like listening to hiss, a low-noise equalizer is essential. The signal-to-noise ratio in the Roland's electronics is high enough that hiss is not noticeable, but a bad audio equalizer will amplify this small amount of noise and add its own noise to the mix. For example, suppose your equalizer has a S/N ratio of 60 decibels. This means that for every 85 dB of sound, you're getting 25 dB of added noise. If the equalizer adds another 15 to some part of the spectrum, that adds up to 40 dB of hiss--which is loud enough to be objectionable. An equalizer with an S/N ratio of at least 90 decibels is recommended.

Effects processor: Although an equalizer can improve the sound a little, an effects processor can work miracles on a digital piano. With a good reverb effect, the sound becomes progressively more spread out in pitch as it decays, similar to what happens in a real architectural space. Two inexpensive reverb units are Behringer's DSP2024P and V-Verb REV2496. The units have a good S/N ratio, but this vendor is known for quality control problems. I've owned one of each, and both have broken down well within the warranty period. (The vendor replaced one under warranty, and the other one, which was rebooting itself continuously, just had a transistor that needed a bigger heat sink.) Of the two units, the DSP2024P has a slightly better reverb than the V-Verb, but its user interface is worse. Other vendors include Lexicon, TC, and Alesis.

A note about noise: The Behringer DSP2024P has been unfairly accused of being noisy. This unit has an input level switch (which Behringer calls an "Operating Level" switch) hidden on the back. If this is set incorrectly, the unit adds a hiss to the sound, because the input level is too low. When set correctly, the signal to noise ratio is as advertised: 91 dB.

Limitations: It is very difficult to play fast repeated notes on this piano. In this respect, the action resembles an upright more than a grand piano. The fastest you can strike a single note is about 300 times per minute. This means you will be unable to play some types of music that use rapid repeated notes. Unlike with an acoustic, the touchweight does not change when the sustain pedal is pressed.

Update (Jan 30, 2011)

The HPi5 was replaced a few years ago by newer models, such as the HP307. This digital piano uses what Roland calls the "SuperNatural sound engine," which includes some synthesized sounds like those found in the earlier V-Piano, along with sampled sounds. Many of the deficiencies mentioned above in the HPi5 have been fixed. In particular, the keys are no longer slippery, and the sound and touch have been vastly improved.

These digitals might not have all the acoustic nuances of an acoustic, but with a digital, you won't have to deal with the many limitations of acoustics. There are many such limitations. The acoustic piano industry is in deep decline these days. One reason is their longstanding failure to innovate. Another reason is piano technicians who refuse to repair pianos if there's not enough profit in it, while at the same time trying to intimidate owners from doing the work themselves, because this threatens their livelihood. On this website, I had a page describing basic techniques for repairing acoustics that piano owners could perform. One piano technician bitterly criticized the page, saying that piano owners should never touch the inside of their piano, lest the clumsy clods break something. If auto mechanics had this attitude, a few people would be driving around in Porsches and the rest of us would have to walk. While this attitude is by no means universal (I've met some very nice and helpful ones), I don't need the aggravation. The attitude is widespread enough that owners of "average" acoustic pianos often find they're basically screwed when something breaks. Another problem, of course, it that acoustics need constant tuning, and it's very expensive to have them moved. These problems don't exist with digital pianos.