Topic: 64 channels on a shoestring - and a Windows Tablet PC

Further to my test of an external SSD, I tried the smallest possible 64-channel recording setup I could think of (without preamps and converters, admittedly) after having come across the Trekstor SurfTab Wintron 10.1 tablet computer, which runs a full-fledged Win 8.1 32 Bit. Prices start from about € 200 in Germany, although I got mine for only 170, including the somewhat mediocre keyboard/touchpad combo. This is the 3G version, there is a Wifi only version as well, which is in fact a bit thicker... The tablet has got one full-size USB 2.0 port, to which I connected a simple el-cheapo USB hub with external 5V power, with hosted both the Babyface USB and the aforementioned external SSD. I did so after having successfully tried it with a Babyface connected directly to the computer, which was running on battery power.

On to a test with the Madiface USB, where initially, the Trekstor's internal 32 GB disk drive (of which about 22 GB remain free) performed so-so, but was unable to record 64 channels. The demo version of Samplitude Pro X2 reported Lost ASIO Buffers (but there were no USB errors in the USB Settings Dialog). 24 channels were no problem, though.
Unlike my positive results with SD cards for Durec with the UFX, the Tablet's internal SDHC card slot would not do more than 10 MB/s writing, even with a fast UHS-1 SDXC card. Samplitude barely managed the 24 channels, with the disk load occasionally going to 100% and one interruption of the recording due to disk overload. Things went a bit better without Samplitude updating the objects during the recording.

The external SSD (much like current fast USB hard drives, I would assume) flawlessly records 64 channels at a disk load below 50%, even while the Tablet PC is running a Teamviewer session (at high quality settings and with audio transfer) across WiFi, and with two devices competing for USB bandwidth on the hub. Audio signal was provided by Media Player playing back an mp3 file off the C drive, which was then split to all outputs in the Madiface's matrix and looped with a cable. I could listen to the stereo audio signal across the LAN on another PC running the Teamviewer client without any glitches, even while 64 channels were being recorded.

Haven't looked at DPC values or so, as there is no obvious issue. Without Teamviewer, the CPU happily reduces clock rate to below half the nominal rate without any apparent issues. All performance meters are very stable throughout. I did not test low latencies, as these are not really required during multichannel recordings. Therefore, I have also not tested simultaneous playback and recording so far, but will do.

The Trekstor also performed well while playing an 8-channel project with some reverb thrown in to bring the CPu load to about 68%. I don't expect this setup to be a killer for low-latency MIDI/VST performance, so I have not really tested that yet.

The device complained about insufficient USB resources when I connected the Madiface XT through the hub, not sure why, despite the XT being manually set to USB 2 mode. The device manager states the presence of an "Intel USB 3.0 eXtensible-Hostcontroller - 0100", although the external connection seems to be USB 2.0 only. Transfer rates of the USB 3 based SSD drive remain below 40 MB/s when connected directly.

Will also test it with the FF UFX, but don't expect any issues.
The setup pictured here is perhaps a bit finicky to be used with full confidence for a major once-in-a-lifetime recording, and I have not yet tested long-term stability over the course of many hours, but it seems like a nice way of reducing weight on mobile recording assignments.

As always, with other Windows based tablets, YMMV...

Some pictures below.

Regards
Daniel Fuchs
RME

http://www.rme-audio.com/support/IMG_3444.jpg
http://www.rme-audio.com/support/IMG_3459.jpg
http://www.rme-audio.com/support/samprec.jpg
http://www.rme-audio.com/support/rec2.jpg

2

Re: 64 channels on a shoestring - and a Windows Tablet PC

That indeed should give Apple something to think about. You can NOT do the same with an iPad for a simple reason: USB audio on iOS devices does not support the so called hi-bandwidth mode. That is the reason that iOS is limited to transfer about 24 channels I/O in Class Compliant mode - and even that already requires to reduce the amount of data transceived by using a 24 bit mode instead of the standard 32 bit one. Same with MFi.

Regards
Matthias Carstens
RME

Re: 64 channels on a shoestring - and a Windows Tablet PC

I got the same message about insufficient USB controller resources when I tried to connect a mouse to the hub next to the Madiface and the SSD. So I guess that answers that, the system seems to be on the edge there. But it works...

Re: 64 channels on a shoestring - and a Windows Tablet PC

More news from the edge....

With all buffer settings in Samplitude maxed out, I can play and record 64 channels each at the same time. Placed the previously recorded tracks on to new tracks 65-128, and started recording 1-64. No errors in Samplitude, and still no USB errors in the Madiface settings dialog. CPU gets some turbo boost to 1.5 GHz, and of course the percentage values for the disk pertain to USB 2.0 bandwidth. If this were USB 3.0, the SSD would do it easily. 30 minutes without errors and counting. All with Teamviewer and Wifi up and running.... One small glitch in the audio transfer at the start of the recording, otherwise nothing noticeable. Despite the CPU running at higher than nominal clock, the back of the tablet remains mildly warm at best - and it is totally silent, of course.

On the topic of Apple, the internal speakers (on both sides) of the Trekstor seem to be a good deal better than those on my iPad 3.


http://www.rme-audio.com/support/rec3.jpg

Re: 64 channels on a shoestring - and a Windows Tablet PC

Recording 64 channels in Reaper...
http://www.rme-audio.com/support/reaper.jpg

Re: 64 channels on a shoestring - and a Windows Tablet PC

... and in Digicheck.

http://www.rme-audio.com/support/dc.jpg

Re: 64 channels on a shoestring - and a Windows Tablet PC

And finally, in a somewhat more realistic setup, UFX and a Micstasy recording 20 channels to the SSD. Will leave this running for a few hours. The internal SD card reader again disappoints somewhat, and needs very high buffer settings for reliable recording.

http://www.rme-audio.com/support/ufx.jpg

Re: 64 channels on a shoestring - and a Windows Tablet PC

Really interesting, thanks for investigating!

So I understand with this hardware it is important to use external drive (SSD), and USB 2.0 limits overall performance somehow, more than the rest of the hardware does.

Microsoft Surface 3 has USB 3, however it's 600 EUR...

Re: 64 channels on a shoestring - and a Windows Tablet PC

Yes, the Surface is quite tempting... I wouldn't really speak of "limited" performance, though, 64 channels is quite something for such a device, is it not? It's the internal SD card reader that is a bit slow. But for smaller recording sesionss of 8 tracks or so, it'll do. Or you could use the internal drive. Will also test an external SD card reader, like the cheap lil' thing I successfully use with the UFX.


Regards
Daniel Fuchs
RME

Re: 64 channels on a shoestring - and a Windows Tablet PC

I read that there is not only a common USB 2.0 port but also a micro usb (2.0?) on the Trekstor tablet. Is it possible to use the micro usb like a standard USB 2.0 port, this way avoiding a hub when connecting audio interface and storage device?

Re: 64 channels on a shoestring - and a Windows Tablet PC

Yes and no... There are so-called USB On The Go cables and hubs to connect external gear to these Micro USB ports. I ordered a hub, a cable is on the way.
http://www.rme-audio.com/support/P1030345.jpg

No use trying to connect a drive or audio device to this little hub, though, transfer rates are dismal, well below 1MB/s. I'm not sure whether that is because of the hub or the port, will try the cable when it arrives. It does, however, let me connect a mouse, which did not work on the other hub.

Quite apparently, there is no bandwidth issue with the USB 2 hub, using Madiface USB and diisk drive together works well. What amazes me most is the stability of this system. I am currently recording 64 channels to the SSD, while streaming HD Youtube video across Wifi - and transferring the desktop including audio (without interruptions) to another PC on the LAN with Teamviewer...  Also tried a USB 3 card reader with an Micro SDXC card, but was getting disk overload after some time, strange... Will test this further later, and also try the device with the UFX. [EDIT] Sseems connecting a card reader to a hub may not work too well. The one that works with my UFX also fails, and does not seem to report back correct disk usage rates... Will try a pen drive next. :-)

http://www.rme-audio.com/support/mfrec2.jpg

Re: 64 channels on a shoestring - and a Windows Tablet PC

Recording with the card reader works fine at lower channel counts, and Samplitude shows sensible disk load values. The little hub here works fine as well, even without external power, running a Madiface USB or Babyface and the card reader or the SSD. With the Babyface instead of the Madiface, I can also connect a mouse, no issues with USB resources.

http://www.rme-audio.com/support/bf_hub.jpg

Re: 64 channels on a shoestring - and a Windows Tablet PC

One more... The USB OTG cable works much better than the mini-hub, and turns the Micro-USB port into a full-fledged USB 2 connection, even with an additional external hub. The SSD will do transfer rates of well over 30 MB/s here. With the hub, I can connect the mouse, the SSD, and the card reader. The connection could probably host an audio interface as well. So now it is possible to separate the disk drive and the audio interface, no hub required to connect both to - even though that is not a problem in terms of bandwidth.

http://www.rme-audio.com/support/otgcable.jpg

14 (edited by Ulrich 2015-06-04 19:46:38)

Re: 64 channels on a shoestring - and a Windows Tablet PC

Amazing... two independent USB 2.0 ports is great for such a cheap tablet, as far as I can see. Surface 3 has only one USB3 (extendable via docking station).

Any new insights on the Madiface XT not collaborating properly here?

15 (edited by Urban 2015-07-24 18:43:17)

Re: 64 channels on a shoestring - and a Windows Tablet PC

is it also possible to control totalmix with touchOSC (ipad) in this setup?

this would be my dream setup! start record in digicheck, put it in the Rack and control the in ear mixes with an iPad.
no expensive Laptop on Stage and a "wlan adapter" for the UFX.

RME Fireface UFX | RME Fireface800 | RME Babyface | RME Octamic II | RME ADI-2 | Audient asp 008

Re: 64 channels on a shoestring - and a Windows Tablet PC

Urban wrote:

is it also possible to control totalmix with touchOSC (ipad) in this setup?

Yes wink

Re: 64 channels on a shoestring - and a Windows Tablet PC

RME Support wrote:

No errors in Samplitude, and still no USB errors in the Madiface settings dialog.... One small glitch in the audio transfer at the start of the recording, otherwise nothing noticeable.

Fascinating thread particularly as we may have to abandon our 2018 MBP for recording purposes.

How are you measuring these errors and glitches? I haven't seen the same dialogue on OSX and iOS...

Eastwood Records
www.eastwoodrecords.co.uk

Re: 64 channels on a shoestring - and a Windows Tablet PC

RME Support wrote:

No errors in Samplitude, and still no USB errors in the Madiface settings dialog.... One small glitch in the audio transfer at the start of the recording, otherwise nothing noticeable.

Fascinating thread particularly as we may have to abandon our 2018 MBP for recording purposes.

How are you measuring these errors and glitches? I haven't seen the same dialogue on OSX and iOS...

Eastwood Records
www.eastwoodrecords.co.uk

Re: 64 channels on a shoestring - and a Windows Tablet PC

RME Support wrote:

http://www.rme-audio.com/support/otgcable.jpg

Sorry to go a little OT here - but is that really a Mouse Pad that has a picture of iPad running TMFX???  Do you sell those tongue  Too cute and 'pun-y' all in one!!!

MADIface-XT+ARC / 3x HDSP MADI / ADI648
2x SSL Alphalink MADI AX
2x Multiface / 2x Digiface /2x ADI8

Re: 64 channels on a shoestring - and a Windows Tablet PC

Interesting indeed.
+1 for a "Gelpad" based solution for mouse pad :-)

BR
Ramses
Win7 Prof, CubPro9.5, UFX+, XTC, ADI-2 Pro FS/DAC, RayDAT, ARC USB, Sonnet USB3-PRO-4PM-E

Re: 64 channels on a shoestring - and a Windows Tablet PC

mjfe87 wrote:
RME Support wrote:

No errors in Samplitude, and still no USB errors in the Madiface settings dialog.... One small glitch in the audio transfer at the start of the recording, otherwise nothing noticeable.

Fascinating thread particularly as we may have to abandon our 2018 MBP for recording purposes.

How are you measuring these errors and glitches? I haven't seen the same dialogue on OSX and iOS...

Sounds like he is using the built-in error detection of Samplitude.
The task manager doesn't really tell about such issues.