Piano World Home Page Forums Our Most Popular Forums Digital Pianos - Electronic Pianos - Synths & Keyboards DPs that support audio over USB: questions

Main question: in general, asking in context of any brand / model of DP known to support, by design, audio over its USB “to host” port , can such DP be connected via its to-host port to the type of external box, often referred to here as “external audio interface” ( Focusrite Scarlett, Presonus, etc.) for the purpose of then attaching monitors and or headphones on the output side of the interface box and thereby listening to the DP’s audio via this set up IE. not listening via the DP’s on-board speakers or line outs or headphones jacks?

I realize from much reading here that Kawai is not among the “any brand’ that might satisfy my question, which is fine by me since Im generally looking to do the above, if i can get confirmation here that it is doable, with a newer Roland or Yamaha DP to be purchased in the future. I also realize that if the above is easily doable it will be doable by way of using an appropriate model audio interface box; having done some presale study of those, it looks like they are available in many models that have the kind of onesy / twosy / or more lines/phones output ports needed to do what i’d like to do.


As it is right now, ive got two two nice DP’s that don’t support audio over their to-host ports, and ive not, yet, ever owned/operated an external AI box but am considering doing both in a near future yet to be suitably predicted.


Happy to hear / see replies from anyone who either has done / are doing the above or know it can be done even if they are not or have never done this.

Thank you.

Good question, I'd love to know the answer to this as well!

My guess is that since the DP is the accessory (hence, the USB jack is TO-HOST), and the audio interface is also an accessory, it won't work the way you envision, since neither device has the required USB host capability and drivers to read the data and manage the bus communications.

The one exception I can think of might be Dexibell. It's designed very much like a GP computer, and I wouldn't be surprised if it can serve as a USB host (another question entirely if it has the drivers to communicate with whatever audio interface you plug into it)?

The audio-USB of the DP is a USB-to-host. (The DP acts as a device). The audio interface (Focusrite, others) has also a USB-to-host socket : it will acts as a device too.

The USB protocol is not designed to make two devices exchanging directly.

The best you can do is to take a computer and redirect the output of the DP to the output of the audio interface.

Edit : My answer is a bit late… it arrives second.

I think you are asking can you connect a usb audio interface to a DP that has its own usb audio interface in such a way that the DP sends digital audio to the external interface. No you can't do that. You'd have to send the digital audio to a computer over usb and then from the computer out to the external interface over usb.

You could share more about what you are trying to achieve in order to get more advice. Me, I used an external interface with a DP that does not have onboard audio interface, and it sat in the middle connecting together DP, monitors, headphones, and optional laptop computer. In this setup I used headphones out from the DP to line in on the audio interface box. Now I have a DP that does have an internal interface and I like having one less device in play, having the monitors connected directly to the DP and then I connect the laptop to the DP when I feel like it. Works well for both practice and lessons.

@Gombessa and @FredericL

Im glad to see the first 2 replies hit on the nebulous (to me) aspect of “usb interface” in context of PCs/DPs/AI box solutions.... but sorry to see that AI boxes are, probably, only providing a USB bus pass-thru function/ path/connection point 😕


The type B “ to host “ port on DPs is telling, to me; it tells me this port must connect to a type A port on a PC or other computer capable of operating as a USB Host .... iphones/ipads/androids and “AI boxes” were not yet really on the map in the mid-90s when USB appeared. The USB connector/port on an AI box is not so telling as it certainly does not look like a ‘to host” port like those appearing on many DPs released yesterday or at least as far back as 2015 .... which may be the main reason why this is a cloudy enough situation for me to ask about it here ..... granted, a Roland or Yamaha model released yesterday probably supports USB audio but those released 2015 probably do not.

As mentioned earlier, Dexibell's Auqaviva OS allows its USB memory (USB Type-A) port to also serve as a USB Host:
https://www.manualslib.com/manual/1602856/Dexibell-Vivo-S9.html?page=19

I imagine this is fairly limited though, as the manual only discusses service as a USB-MIDI host (so the DP can control another MIDI keyboard without requiring a PC in the middle). Worth exploring further, though?

"To Host" is a USB-B connector. Even an old USB printer uses a USB-B connector for the purpose of connecting to a host (the host being your computer). Audio Interfaces, similarly, are slave devices, not hosts. They have B connectors, and must be connected To a Host (e.g. computer). You cannot connect one host to another host, or one slave device to another slave device.

This is just the way USB works, and has nothing to do with audio over USB in particular, which follows the same host vs. slave device rules as everything else.

Sounds like you have the correct understanding, but characterizing that they have usb pass through is misleading because thats what a usb hub does, and external audio interfaces don't work as usb hubs. External interfaces only have 1 usb connection.
The essential function of external audio interface is that they convert between digital and analog. To allow different scenarios of digital to analog conversion use with different audio sources, they have features like preamps, simple mixing capability, separate analog outputs for monitoring, midi usb conversion. The reason to use one, instead of just connecting a computer directly, is to get higher quality, more channels, use the additional features, and have the convenience of leaving everything connected and just taking the computer away when needed.

A USB hub is designed to enable communications between a hosts and each devices. Not between two devices.

Yes, the manual describes only two uses (Flash ram, keyboard), not the audio interface mode which would need a dedicated piece of software inside the Dexibell. I can be wrong, but I don’t think it would work… especially if the Focusrite is not USB compliant.

yes, but .... if the USB port on a 2i2 is a type-B-to-host port the way some people say as though its been a forgone conclusion, it certainly does not look like one. To me it looks like the type of USB port found on some older iPad Host computers.

The
The current 2i2 is using a USB Type-C port, which is "universal" and does away with using physical form factors to distinguish host from peripherals (as with anything else, USB is getting more and more complex and supporting more use cases, so the distinction doesn't really make sense nowadays). It's just the shape of the port though; just because a device is Type-C doesn't mean it automatically has host capability.

Think of a mobile phone or battery bank. They COULD serve as host or peripheral depending on what you connect to them, so in the old regime they would require two physical connectors. Now, it's a matter of one port but you just gotta know whether they will talk to each other or not.

Officially the plug/socket is supposed to follow the rules.
So a rectangular "A" jack meant "I am a master".
A "B" square jack meant "I am a slave device" (like a printer printer).
Then there were the mini and micro jacks ... also slave devices.

But, as Gomessa suggests, the world has changed in the last quarter century. USB has been put to uses not anticipated in the early specs.

Add the frustration of plugging in a USB connector (try/wrong! ... turn it around/try again/wrong! ... turn it around again/right! finally!) prompted the reversible plug arrangement ... the C type.

I'm still frustrated, though ... because none of my devices use the type C ... yet.

Right. With the transition to USB-C, you can't tell whether something is a host or slave merely by looking at the connector. That said, AFAIK, there are no keyboards that use USB-C.

Of course nobody here has any way of previously knowing this, but in the mid to late 90’s, i thought about - how hard would it be to develop a device that was not a full PC but had enough intelligence to function solely as a USB host - having grown weary of so many customers calling into tech support, where i worked, and asking for that very thing..... back then it was still requests for typical serial connectivity ..... soon became KVM switching and USB extenders and Async RS232 converters and passive hubs and powered hubs ..... back then, i took for granted that some innovator would eventually make such a device...... oh well 😕

Whatever the connectors, a USB device can only exchange with a USB host.

Some connectors makes things more complex : micro USB-B has a 5th pin which is use to tell the phone « you should act as a host » or not… and the phone has both behaviour in its software. This permits a on-the-go cable to work.

I don’t expect devices like audio interfaces and digital piano to implement fancy behaviour. Then one behaviour (device only on the B socket, storage on the A socket, perhaps keyboard, Wifi dongle)

Perhaps (20 years later), more devices will work as a host (generalisation of USB-C, generalisation of MIDI 2.0…). Perhaps…

but a USB host still needs software/drivers in order to actually do anything. So the question is, what do you want to plug into it? You can currently get devices that are USB hosts that do nothing except provide MIDI connections.

Yes, USB hosts need drivers, but they can use generic driver for USB Class Compliant devices. There are class compliant MIDI controller, but also audio interfaces. (But I don’t know the status of most audio interfaces…)

There is a thing called usb on the go that allows a port to be a host or a slave and it has been around for awhile.

In theory there is nothing keeping an audio interface manufacturer from implementing it and allowing direct connection to a keyboard.

Back in my day I wrote some embedded usb software for communicating with a joystick and there are plenty of usb stacks these days for software developers.

There is a class for audio interfaces so like mice and keyboards it would be plug and play.

I think maybe a more useful thing would be a s/pdif digital output from the keyboard. I see a lot of amps that support this input.

I hope someday that usb-c becomes the standard connector foe keyboards. I think the Roland a88 Mkii midi keyboards might be one of the few using this connector.

I may be missing something here, but what would be the advantage of connecting the keyboard to the audio interface? Do you want to record within the audio interface? Substitute a DAW? If not, then the signals would need to be moved from the audio interface to the computer... What would you gain by having a stop-over of usb audio or midi signals at the audio interface? Let them go direct from the keyboard to the PC and avoid another discussion about latency...