Moduleless A-E conversion for $100

[kremonte]

Money's tight and my drums are loud. My plan is to build some triggers and connect them each to a $1.50 USB audio interface (with mono mic in), all of those connected to a USB 3.0 hub and into a Surface Pro hosting Reaper with DSP Trigger (to convert the transients to MIDI) and something like AD. My pared-down plan includes a dual-trigger snare, three toms, kick, and two dual-zone cymbals (crash and ride). I'm ignoring the hi-hat for simplicity's sake. With this setup, DSP trigger should be able to produce a 3-zone snare, 3-zone ride and crash with choke, and 2-zone toms. Since each input is mono, dual-trigger TRS connections get split into dual TS and take up two interfaces.

Prices buying most of this stuff off eBay (from NA only, parts from China are cheaper but take longer to arrive):

13-port USB 3.0 hub: $30
USB audio interfaces x10: $15
27mm piezos x10: $10
3.5mm TRS jack x10: $5
3.5mm TRS 2m cable x10: $5

Electronics total: $65

and retail stuff to mount the triggers and make the mesh heads:

48x96" fiberglass screen x2: $14
3" L-bracket x10: $9
2'x4' MDF: $7
24"x36"x3" foam: $5

for a grand total of $100 of hardware purchased. I'm also frankensteining a couple of old 3.5mm TS-M connectors to split the stereo signals into mono (but still use a single wire from each drum).

This might be a terrible idea: no module, all done through VST in a DAW running on Windows on a tablet, all input is routed through cheap audio interfaces with questionable DACs. But I'm spending $100, if it doesn't work then at least my drums are wired to plug into a module, and if it does then it's easily expandable to have 3-zone toms, more cymbals, etc. Hi-hat will continue to be a problem with this setup because at the moment, DSP Trigger (nor anything else AFAIK) can't do much with HH transients, but having an acoustic HH isn't that bad.

I'll report back at least at the end of the week when the hardware arrives and I get it all put together. I've done a small proof of concept with a single dual-trigger drum and a similar hardware setup and it works fine, the latency is acceptable for live play.

I appreciate any comments on this setup, if anyone has done anything similar, more reasons why it's/I'm stupid/brilliant, etc.

[perceval]

I doubt the tablet will have enough horsepower to drive all those inputs with DSPTrigger Could be a fun intro to DIY though. Also consider getting a used TD-3 for a little over $150, and save you the headaches and the time.

[ThePod]

Or buy a Rockband drum set and use that for your pads and triggers. BFD eco can be had for $29 if you look for a sale. Alesis trigger IO available on ebay for $62 currently. Lots of options

[fulrmr(Daniel)]

The surface pro might be ok. I believe it has a dual or quad processor with 4g of ram. You will hsv

ave to get an external disc drive to load the the software though. That said.....you need a pretty good TMI to handle the pads before sending the midi to your tablet or external sound card. The internal sound card of the surface will most likely have way to much latency to be playable.

[hairmetal-81]

Welcome to the forum, kremonte.


You could always give asio4all a try, to get the latency down...Could you provide us with a link to your $1.50 USB audio interface?

Personally, I fail to see why you'd have to convert every pad into an USB-signal first - your USB-hub might end up as the 'bottle-neck'...
The more sensible way would be to get a good TMI (or a larger, used, audio interface), where all the pads are connected using standard audio-cables, and then are sent to the computer using one USB-cable!

...saves you the hub, and is the more reliable solution, IMO.



Good luck!

[kremonte]

Thanks for the feedback all. I am indeed already using ASIO4ALL drivers (which allows me to use multiple audio interfaces simultaneously and with low latency). I actually already have an old GHWT drum set (and some of an RB2 kit) but they were both already in various states of disrepair, and, more crucially, feel nothing like an acoustic kit. I'm a hobby drummer, actually got into the instrument from Rock Band, but after some 5 years on my kit, the little RB set doesn't appeal much to me. I've used some of the piezos and jacks from that for the proof of concept.

I was (and am, albeit a lot less) worried about bottlenecking through USB. Bandwidth shouldn't be an issue though, as the hub is USB 3.0 so each port is receiving 3Gbps/13=29.5Mbps, more than enough for a single channel of audio. I am more worried about OS overhead and IRQ concerns from using so many devices, but AFAIK Win 8.1 can smoothly handle over a hundred USB devices concurrently.

Another factor for me choosing to use VST to convert transients to MIDI is that it something like DSP Trigger seems to offer extremely advanced triggering capabilities from a very simple kit, allowing me to get high quality sampling and layering without spending a fortune on a good module. Sense would say, to save the headache and bottleneck, to use an interface, at the very least to consolidate the audio, but with the excessive bandwidth available over USB 3.0 I'm not too concerned. The processing power of the Surface Pro comes into play, but it's more a laptop than tablet - with 4GB of ram, an SSD, and a core i5, I think it can handle such a setup with moderate, but not runaway success. However, without a module I'm skipping one more layer of latency to help make that back.

These would be the audio cards: http://www.ebay.com/itm/130895216988

Very hard to find any technical information on them. $30 is a gamble I'll make for a potentially 20+i/o interface.

[TheYardbird]

I'm not that experienced at all with setups like this and even I am a bit sceptical to the outcome of this. If you get it to work then - Awesome! But I wouldn't get too surprised if it turns out to be too much delay or whatever problem you might encounter. This is quite intriguing, make sure to post some detailed reports of the outcome of this!

[kremonte]

Received the eBay loot today. Each of the audio interfaces is stereo input! Doesn't seem noisy or high-latency either. ASIO4ALL lets me select all the inputs - I'll have to name each adapter uniquely to avoid confusion. Testing with 3 sensors on 3 inputs (only stuff prewired to test with is mono! gotta bust out the soldering iron) outputting from my speakers there was no noticeable latency, but I didn't do more than mess around. I have my ASIO buffers all at 128 samples, which is working alright for now. My remaining worry is loading up a dozen tracks with VST plugins on them, we'll soon see at what point this econo-setup begins to falter.

[Vectron]

Interesting project.
Initially you said you have a bunch of "$1.50 USB audio interfaces (with mono mic in)";
and now you say "Each of the audio interfaces is stereo input!" But on your pic of ASIO4All, I can see each interface
says Input: 1 x 44.1 -48kHz, 16bit.
Therefore, it is MONO mic input.

[theimageofall]

This is an interesting project....be interested to know how it turns out.

[ohlarikd]

I am not understanding something here... the piezo is connected to an 1/8 TRS plug, and this is plugged directly into the audio line input of the USB Adapter? And this is able to accurately trigger a VST? I could see it perhaps making some sort of sound, but does it respond and play well?

[Vectron]

I am not understanding something here... the piezo is connected to an 1/8 TRS plug, and this is plugged directly into the audio line input of the USB Adapter? And this is able to accurately trigger a VST? I could see it perhaps making some sort of sound, but does it respond and play well?

Yes, but it is actually mono mic input(not audio line input) of USB adapter. So, there's one piezo per adapter.
I hope original poster will give up some updates on how well it is working out.