Piano World Home Page Forums Our Most Popular Forums Digital Pianos - Electronic Pianos - Synths & Keyboards Any Kawai piano with USB audio interface?

Right, sorry I think I got my reply to you mixed up with stuff that Burkey said.


True, but a dedicated DAC is has a lot less computer "stuff" and is designed completely around providing the best quality analog output, whereas in other types of devices the analog audio is an afterthought and the focus is much more on the digital computing.


In a well-designed device designed for high-quality audio the digital and analog sections have a lot of isolation of power supplies and whatnot.


Yes but they should, because using higher-quality headphones with an amp that can drive them properly will make vastly more difference than whether you're using an analog audio input to the keyboard or using audio over USB. It's very unlikely the Kawai headphone amp could properly drive good headphones such as planar magnetics. Fortunately there are many great and inexpensive products that combine a USB audio input, high-quality DAC, and powerful headphone amp in one small box.

I think to say that the engineers at Kawai are not isolating their power supplies and doing everything they can within limits to produce a good analog section would be a discredit to them.

If you throw in a planar magnetics headphone that might cost as much as the digital piano.

The point of the usb audio in the digital piano is it makes a very clean setup and is essentially free. And the digital piano engineers do spend a good amount of time trying to make their pianos sound good which means they have a good enough analog section.

Now based on this discussion maybe the rationale behind kawai’s decision is:

1 most people will be quite happy playing the internal sounds through the internal speakers or headphone jack

2. The amount of people who want sounds produced externally are mostly enthusiasts and tinkerers and they will just go buy all kinds of other stuff.

Making the market for people who want usb audio on the digital piano small in the eyes of Kawai.

I’m sure if Kawai sees that it is impacting their sales, usb audio will be added. If not, they will just continue on their same course.

It's very common for all-in-one type devices to not do nearly as good of a job on specific features as dedicated devices. I'm sure Kawai focuses much more on things like the action and the quality of the samples than on investing in audiophile-level DACs and analog circuit design. And even on the samples people who care the most about quality are using external VSTs to generate the sound rather than relying on built-in sounds.


Planar magnetic headphones and very high quality DAC/headphone amps start at $100 or so each and would outperform cheap headphones and built-in amps on Kawai keyboards costing many thousands of dollars.



No it's not free because it requires engineers to design and they'd have to buy different chips and rework their circuit board manufacturing and so on. They probably have an architecture they're happy with and don't want to change it for a feature that very few people will use, or perhaps it's on their roadmap for sometime down the line when they were already planning to do a significant update to their architecture for other reasons. Maybe they've even got a big supply of parts or completed circuit boards and aren't going to update the hardware until they run out.

It doesn't make the setup any cleaner for most people because they're not using USB for MIDI and so they have no need for a USB connection to a computer or other device at all. They'll simply be playing their piano and if they want to play along with some music they'll plug their device (more likely a phone or tablet than a computer) into the keyboard via a 3.5mm analog audio cable or they'll use Bluetooth.

I think you have some misconceptions about the technology. Your DP has a DAC chip inside it to convert the digital piano samples to analogue sound. When you attach your DP to a computer/VST, the DP is sending midi over USB to the computer, and the computer is sending digital audio (linear PCM) back to the DP to be rendered by its internal DAC. These communications are being multiplexed on the same USB wire.

When you install the driver on your computer for your DP, you are installing a soundcard driver just like you would do for an external DAC for your computer. You then can turn on your DP and use it as a soundcard/DAC for your computer even if not playing anything over the keyboard to generate midi. That is all this USB audio interface is doing. Having an external DAC for the VST also will work best with external monitors rather than the speakers in the DP.

It is not at all free. The USB implementation in the piano has to function as a USB host and not just as a USB client. This requires additional hardware and additional firmware, and a more complex implementation because a USB host has to operate asynchronously.

Ultimately, the VST output will go to a DAC, from there to an amp possibly by way of a mixer, and from the amp to speakers/headphones. The differences are whether the DAC and/or mixer and/or amp and/or speakers are in the DP or external.

The mixer can be analog or digital whether or not it is in the piano. In the case of a Kawai DP, if you run a DAC output or other analog signal to the keyboard analog input, I have read on PW (but not from an authoritative source necessarily) that the mixer in the keyboard is digital. This would mean that the analog signal is digitized, mixed with the Kawai sound digitally, sent to the internal DAC and on to amp and speakers internally or externally. If this understanding is true, then Kawai would need to include an ADC chip in the piano, which would add its own cost. It is not how I would implement it, and it may not be how Kawai implemented it. I would want the mixer to be analog, but the digital implementation would allow routing the external sound or the mixed sound through DSP effects. I don't use the feature in any case, so I've not investigated it further.

Once again:
The discussion here is not about DACs: it’s about how the audio is sent to and from the digital piano. Which was my point: DACs and ADCs are not used in that process - so stop mentioning them.

Furthermore: you don’t need to install any driver - macOS has USB Audio support built-in. It’s therefore nothing like a sound card driver for an external DAC.

We’re specifically asking about USB Audio - not S/PDIF.
Can you actually provide any examples of what you claimed?

If you send the audio to the digital piano over USB then you are choosing to use the digital piano's DAC. They go hand-in-hand.



External DACs are almost all class-compliant just like digital pianos that support USB audio, so they don't require sound card drivers on macOS either. Fancier audio interfaces that are much more than just external DACs often require drivers.

USB is just a different transport for digital audio. The fundamental issues of mixing digital audio remain the same. As I said I'm not even aware of any devices that can handle mixing multiple USB digital audio streams, so USB audio just isn't usable at all for that application.

In the case of a digital piano mixing its internal sounds with USB audio digitally, without synchronized clocks there will need to be some buffering, re-clocking, sample rate conversion, dropping of samples, and/or interpolation of samples -- resulting in some loss of quality (although you may not notice it). Some keyboards may choose to avoid those issues by converting the USB audio and the piano samples with separate DACs and then mixing them in the analog domain before sending them to the amp/speakers and analog outputs. You'd have to look at block diagrams of every such piano to see how each one handles it.

No, the DP acts as an device when used as an external DAC. Its squared USB socket (USB type B) is not designed to be used with an other logic.

You can’t link 2 USB hosts by a cable… then if you link a PC (host) to a DP, this one must behave as a device, not a host.

Note that the DP already acts as an host with a memory stick (flash RAM). But the socket is USB type A.

The only sockets which can be used as host and as device are USB type C, and micro and mini USB type B (these versions have a 5th pin not present in classic USB type B, this pin is used with the On the Go protocol designed for tablets and smartphones).

I’m fairly certain that USB Audio only supports 16-bit 44.1kHz, so the onboard mixing doesn’t have to worry about any such sample rate conversion.

As I mentioned, I haven’t encountered any of the issues you describe in the past 2.5 years, and I haven’t seen anyone here on piano world experience them either.

Incorrect:
If you send audio data to your digital piano via an external interface you are still using the digital piano’s DAC.

You’re choosing to use 2 DACs: one inside the external device, then an ADC inside the piano to convert the analogue signal back to a digital signal for mixing, and then the piano’s DAC to convert the digital audio back into analogue for line out, headphones, and/or speakers.

And that’s, as I explained earlier, why it’s a totally stupid idea.

Why would any sane person choose to connect one USB cable for an external device + 2 analogue cables for inbound sound from the piano + 2 analogue cables for outbound sound to the piano + potentially a power cable for the device. That’s 5 or 6 cables plus an external device versus 1 single cable for USB Audio. You’d have to be totally bonkers to pay extra for more clutter plus inferior sound.

As Doug mentioned earlier, the main use case for an external device is to record analogue instruments or vocals, or to bypass the digital piano completely to connect to your sound system or headphones.

But those use cases don’t directly involve a digital piano and are therefore off topic for this discussion.

The point is that by itself is irrelevant. It does not matter whether the wire between the DAC and amplifier (or DAC itself) is inside the piano case or outside the piano case. It carries analog audio between the DAC and output stage op-amp either way. There may be other aspects about what is in the audio path in the piano that matters, but that applies to both architectures.

You have problems dealing with basic logic here. I said if you use USB to send audio to the piano then you're choosing to use the piano's DAC (versus a dedicated external DAC or the internal DAC of the computer). I said that because you claimed that "DACs and ADCs are not used in that process" which was blatantly wrong.

I never said that if you send analog audio to the piano that the piano's DAC isn't used for anything. You're the only one who seems to claim that somehow no DACs are involved when you use USB audio. However some pianos (particularly ones that don't support USB audio) may mix the analog inputs with the piano audio in the analog domain and so there may be no additional ADCs or DACs involved with that part of the audio.

That may be a limitation of a digital piano that supports USB Audio (precisely because of these issues), but I can send anything up to 768Khz 32-bit audio to my DAC over USB, and I can also send non-PCM audio like DSD straight from SACD discs which many audiophiles prefer.

Even if you limit the USB interface to the keyboard to 44.1Khz, if the music or other audio you're sending to the keyboard isn't 44.1Khz then it has to be resampled inside the computer first, which eliminates the "bit perfect" digital audio chain that many audiophiles strive to preserve.

The internals of most DP's almost surely have a more complex and less clean audio path than:

computer -> external DAC -> powered monitors

The path with the external DAC will be cleaner audio and you can use whatever quality DAC and monitors suit your heart's content and budget. If the piano only supports USB 2.0, that also is a less than fully desirable constraint.

The audio system in a DP is not, shall we say, an audiophile's dream system.

Actually I’d say the dp almost assuredly has a less complex path.

It goes straight from the “computer” to the dac, no usb.

Straight to the powered speaker, and not into some additional a2d computer d2a amp in a lot of monitors.

Usb audio comes in 3 classes which are wedded to different classes of usb 1,2,3

Interestingly enough there doesn’t appear to be a limit to the sample rate or bit width for samples in the class specifications.

Usb 2 is way more then adequate for any stereo audio.

Off hand Roland with the fantom supports 24 bit 96khz
Rd-2000 192khz 24 bit

Fp-90x 16 bit 44 kHz

Korg nautilus 24 bit 48khz

Same with dexibell

I believe Yamaha is 16bit 44 kHz

I don’t see any reason the current hardware in a kawai’s digital pianos could not support that bit rate/depth with lowly usb 1.1.

Audiophile discussions are like debating religion, I’d rather not do it.

Obviously there is some cost associated with having usb audio in terms of software.

I am it aware of any but it wouldn’t surprise me if there might be some intellectual property issues.

Windows as of 2020 supports usb audio class 2 in the operating system as does I believe iOS, android, and macOS.

So at least you wouldn’t have to maintain drivers for those operating systems.

Personally I consider usb audio an important part of my purchase decision.

Given that a digital piano is essentially and audio interface it makes sense to me that it should be part of the dp.

Certainly more important then supporting 256 general midi sounds.

But that is just my opinion.

I believe Kawai has decided usb audio is not important to their existing and future customer base at least at this moment.

Your DP would not be able to produce any sound at all from its digital samples or from a VST connected digitally to the DP without its internal DAC. Why would you think otherwise?

Whether or not a MAC has out-of-the-box support or requires a driver to be installed to support an external soundcard is not an architectural distinction.

By trying to define the problem as whether or not a wire plugged into the piano carries a digital or analog signal, you are ignoring all of the components that actually affect audio quality, and focusing on the feature that has no impact on it. If the analog wire to the piano produces inferior audio quality it is because an inferior component was used in the audio path. The same is true of the digital wire.

Having the piano function as a DAC/soundcard for your computer is a convenience. You just need 1 USB cable between the piano and computer to make it work. You may not need a separate mixer or separate monitors. These are tangible advantages for many DP owners. I could see an owner of a Kawai piano with built-in speakers that the player uses wanting that.

I was referring to VST audio rendered by the DP vs by an external DAC and monitors.

Using the DP to render the VST involves:

computer -> USB wire -> digital mixer in DP -> DSP effects -> internal DAC -> amp -> speakers

You can use an analog amp and monitors if you don't want a DSP tier in monitors.