I hope I'm posting in the right forum. And I hope this question isn't too dumb, but... 
 
I’m confused and hoping to be pointed in the right direction regarding using MIDI with Sonar Professional, which I just got and am eager to get set up and working. My next piece of gear is an audio interface, and my question deals with MIDI/no MIDI.
I have a Kurzweil SP 76 stage piano with MIDI capabilities. I also have a Baldwin RP 100 with both MIDI capabilities and a USB out. I also have a Roland TD-11KV digital drum kit, with both MIDI and USB connectivity.  My question is, can a digital musical instrument function as a MIDI control surface via a USB connection?
 
If not, then that ends my quandary over whether or not the interfaces I’m looking at have to have MIDI capabilities. There seems to be a slew of them out there that have no MIDI (there are also digital keys out there with no MIDI, but USB only) and I can’t understand why a piece of gear so key to interfacing with a DAW like Sonar would not have MIDI, especially given the power and flexibility.
 
I'm looking at two-channel interfaces and am checking out the usual suspects: M-Audio, Presonus, Focusrite, Tascam, Roland. My budget is around $150, and it all comes down to MIDI or not, and whether or not the interfaces are USB 2.0. 
 
Thanks for any help and direction! I’ve found y’all very generous and helpful.
Billy
 
 

For me, if you have any gear that has real MIDI conectivity then you should make sure your interface has the ports. Most good ones do so it's kinda dumb not to add that feature to your list. 
The differance is that if a keyboard or any midi device uses USB only, then that has to have it's own MIDI drivers for it to function. 
If the device has DIN midi then your audio interfaces drivers handle the MIDI. 
So in you situation plug the SP 76 in to your interfaces MIDI ports then the other 2 devices can use the USB connections. That way all 3 will be availlable in Sonar as input devices at all times. 
 
There's no differance in midi functions between USB or DIN Midi connections. Some say USB can be faster. Myself I've not noticed a differance as I use both. 
 

You can always get cheap (even under $10) MIDI to USB converter. There is no signal "quality" (if it works at all), latency is not perceptible (MIDI standard is slow) , most cheap cables work throw standard MS driver.
So I would not exclude 2i2 just because it has no MIDI, but if you have/plan e-guitar, that is not the best choice.
 

MIDI controllers can certainly function with a USB connection, if that connection is set up to carry MIDI messages. Most keyboard USB connections transfer USB-MIDI data only (which contains additional identifier data to what the standard USB stream includes), but it is possible to use USB to transfer audio data as well. Standard serial MIDI (5-pin DIN) transmits one 8 bit event after the other over 16 channels limited to 31.25 Kbits/sec, so it is not impossible to stretch out a stream of notes or controller messages so that an audible lag is generated. The transfer rate of USB is dramatically faster than the direct MIDI standard. That allows the MIDI stream to be moved to buffers at both ends faster as well, and should allow a lot more data transfer without arpeggiation of simultaneous notes. In fact the MIDI-USB standard allows virtual MIDI cables, so that the 16 channel limit can be broken. The actual performance is going to depend on how the manufacturer implements it.
 
But I agree that if you have DIN connections as an additional option on your equipment, it is not a bad idea to get a DIN MIDI interface as well, by itself or built into an audio interface. The DIN MIDI spec is likely to be supported for a long time, but it is not rare for the maker of a USB enabled controller to go out of business or stop writing drivers for new versions of your operating system. Without controller specific drivers you may not be able to get USB to work. But a cheap MIDI to USB convertor with its own current OS drivers would still be able to read and transfer MIDI from your DIN connected controller. Of course if you only have a DIN connector you have no option. 
 
http://www.usb.org/developers/docs/devclass_docs/midi10.pdf
 

The question is do your piano and drum kit have USB midi connectors? If they do, you should be set. If not, you'll need a midi interface and cables. Many inexpensive audio interfaces also have midi ports.

I was faced with the same dilemma when I left an XP desktop and wound up getting a Win 8 lap top … 
Wound up looking around for a USB audio interface and had to decide if getting one with midi was the right choice or not. 
Due to finances I was real tempted to pull the trigger on a 2i2 …I'm glad I didn't and I wound up getting the 2i4 … 
A few days ago I wound up picking up an older 76 keyboard workstation dirt cheap …this thing only has midi no usb …
Now it happens to be true that I could run a midi to USB cable if I wanted to , but then I would have to deal with limited USB ports on my lap top ….
My suggestion is if you are able to bump up and find an extra 40 or 50 bucks to get a USB interface with midi , you may be happier in the long run …
 
Kenny

Wow. Thanks for all the input and considerations. If an instrument has USB connections -- the Kurzweil SP 76 is about 10 years old and the Baldwin KP 100 is about 15 years old -- can I assume it is a "MIDI-USB" capable -- going back that far? The manuals only reference that as a "computer connection." The Roland kit is only about 2 years old, so I'm assuming it is MIDI-USB capable. 
 
Come to think of it, azslow3, I have a Breedlove Pursuit Concert AE guitar with both 1/4" and USB outs. I think I'll go with an interface with MIDI connections to remove any doubt and provide the most flexibility. 

Billy86
Wow. Thanks for all the input and considerations. If an instrument has USB connections -- the Kurzweil SP 76 is about 10 years old and the Baldwin KP 100 is about 15 years old -- can I assume it is a "MIDI-USB" capable -- going back that far? The manuals only reference that as a "computer connection." The Roland kit is only about 2 years old, so I'm assuming it is MIDI-USB capable. 

Kurzweil has no USB, so MIDI to USB solution is required (extra converter or in audio interface)
 
TD11 has drivers for all Windows versions (up to 10). MIDI and audio (ASIO, so you can reasonably good use it with Sonar or Standalone Drum VST even without extra audio interface). I have it, so that is not theoretical statement.
 
It is hard to predict either Baldwin will work. But since you have computer, you can just connect Baldwin and see either you get one more "MIDI device" in the list.

kennywtelejazz
I was faced with the same dilemma when I left an XP desktop and wound up getting a Win 8 lap top … 
Wound up looking around for a USB audio interface and had to decide if getting one with midi was the right choice or not. 

I find a single 4-port unpowered USB hub handles a MOTU MIDI interface (with 5 ports, all in use), MS-20mini, a sequencer and a controller keyboard without problems. Most of the connected stuff only uses one channel each, so I don't know how well things would scale if I needed to push lots of channels out of each MIDI port, but unless lots of multi-timbral synths are involved that's a pretty unlikely scenario I would think.

USB bandwidth is huge compared to MIDI's requirements.

tlw

kennywtelejazz
I was faced with the same dilemma when I left an XP desktop and wound up getting a Win 8 lap top … 
Wound up looking around for a USB audio interface and had to decide if getting one with midi was the right choice or not. 

I find a single 4-port unpowered USB hub handles a MOTU MIDI interface (with 5 ports, all in use), MS-20mini, a sequencer and a controller keyboard without problems. Most of the connected stuff only uses one channel each, so I don't know how well things would scale if I needed to push lots of channels out of each MIDI port, but unless lots of multi-timbral synths are involved that's a pretty unlikely scenario I would think.

USB bandwidth is huge compared to MIDI's requirements.

 
That may work for you and it sounds pretty cool actually ….  
 
Which MOTU interface are you talking about ? is it Midi only or does it also do audio sound card duty also ?
Is it in the OP stated price range ? If it's Midi only why the hell are you choosing to misquote my post to begin with ? 
 
I thought the OP was asking for an audio card on the cheap and whether he needs to get one with Midi or can he pass on that feature to keep the card in a select price range and just hook up his Keys w USB 
I'm not sure why you quoted me cafeteria style ? 
Is this thread about an inexpensive audio card and whether or not it needs to include Midi ? or is it not ?
 
I never once said it couldn't be done w out having midi in the USB sound card interface  …
As far as running a non powered hub goes , sure I have gotten decent results running my M Audio USB controller connected to a non powered hub , on the same hub there is also a mouse , an external powered HD in an enclosure , an external USB HD that is powered by the USB port and a thumb drive connected …
In my case all attempts at running my 2i4 on a hub has failed miserably .It simply will not play nice on a hub  
I have to use up one dedicated USB port to run it w out problems and my current lap top only has 2 USB slots ……
 
Now it may be the brand card I have , but if I got to go there and use up a whole USB port for my soundcard you better believe I'm gonna want to have midi on the sound card 
 
 
All I told the OP was if he could swing an extra 50 bucks he would have a lot more options for audio and Midi combined 
 
 
Kenny