A somewhat odd use of multichannel recording

So I occasionally assist/do consultations helping academic departments at my local campus select A/V gear when they have need for it for labs, etc.

Right now they are designing a lab where they want to be able to record all the participant's voices simultaneously. I don't think they realize how expensive a proposition this might be--we're looking at ~25, 26 channels. I am basically trying to find a way to suggest the cheapest (and most stable) method of recording say 26 mono voice channels simultaneously. Obviously I need plenty of analogue I/O.

If anyone has any ideas in this department feel free to fire away, meanwhile my research and deliberation continues ;)

you could probably rent a mixer somewhere, though idk.

they actually need to separate the voices, hence they need multichannel recording. and i just found out make that 30 channels :D

it will be fun planning this one out :)

oh, separating the sounds then recording, ok. i think i read somewhere of things made for that.

:\ I'm not sure that firewire/USB (hah) interfaces for that many simultaneous channels even exist, so the computer route is probably going to be a no-no. Perhaps a large hard-disk recorder?

yeah, i think you're totally right on that one. It's pretty rare to find more than 8 channels of analogue i/o even on larger interfaces. i guess you can get modular interfaces, i've yet to run across one that goes above 16 in that department

  On 5/28/2010 at 8:43 PM, futureimage said:

:\ I'm not sure that firewire/USB (hah) interfaces for that many simultaneous channels even exist, so the computer route is probably going to be a no-no. Perhaps a large hard-disk recorder?

Perfectly do-able. One way of doing it would be to get an interface with additional digital i/o like adat and then team it up with one or more multi micpre with equivalent digital outs. Off the top of my head, something like the focusrite octopre, but there'll be cheaper and more expensive options. Actually 30 channels might be pushing it, but I'm sure you could find a solution along these lines.

yeah, i know you could get a fireface 800 and one or two ADAT lightpipe input widgets... that's probably not the cheapest route.

you could possibly stack cheaper interfaces -- delta 1010 will support four in the system -> 40 potential input channels. who knows if that'd make the pci bus take a dump.

if (microsecond) timing is not cruical, just use multiple computers/cards?

  On 5/28/2010 at 9:13 PM, TwiddleBot said:

yeah, i think you're totally right on that one. It's pretty rare to find more than 8 channels of analogue i/o even on larger interfaces. i guess you can get modular interfaces, i've yet to run across one that goes above 16 in that department

even my AW4416 only comes with 8 analogue ins, as standard. i upgraded it with another 8 a while back.

Buy 2-3 of these. They are usually at quite great prices on ebay in good condition (+/- $1000). They aren't the best of the best as far as quality goes, but for what you are trying to achieve they should be above and beyond in performance and quality. Work on mac and pc.

http://pro-audio.musiciansfriend.com/product/MOTU-HD192-Core-Computer-Recording-System-PCIe?sku=585677

Also I think you can use up to 3 of these at one time using the pci card.

Edit: what is your budget anyways?

If quality isn't so much an issue you could buy a bunch of inexpensive mixers with pre-amps or at least gain control. Then send the outs from that to a cheaper i/o expander. MOTU and presonus are good options. MOTU has another box, the "24 i/o which is all 1/4" jacks . but it is 25 in one box and they usually go on ebay for +/- $700. Presonus has something similar but it's 16 channels 1/4".

Also if it's for school you should be able to get some educator discounts. So buying new could end up being cheaper than getting used on ebay. You can always contact the companies directly about that, as the retailers usually only carry software related educational discounts.

Thanks for the suggestions.. good ones here!

I don't think the budget will be too much of an issue. And yes, they really only need to record voice and will probably be using either standard conferencing pzm mics or condenser mics--we certainly won't need fancy pants apogee preamps or 32-bit 96khz recording.

I also just found out that they don't really need simultaneous multichannel playback.. which means using multiple computers with multiple interfaces is suddenly an option. This will make things significantly easier.

A fine weekend to y'all.

i'm interested in hearing more about this project! it crosses my mind that even if they don't THINK they need playback of all channels at once there could still be huge advantages to having everything contained in one system. pm me, i'd like to see if i could be any help!

yeah what exactly is the need to record all those voices at once? Also, take note that there can be bad microphone bleed with that many people close to each other.

absolutely. i'm actually not quite sure the reasons why, and yeah that's actually a very good point, 30 people in a room, there's going to be a lot of bleed =) the other problem of course, is that they are not musicians and it's going to require some support to get them using a multitracker in even a very basic sense ;) will keep you posted as this project develops and I find out more info!

  On 5/30/2010 at 7:50 AM, A/D said:

i'm interested in hearing more about this project! it crosses my mind that even if they don't THINK they need playback of all channels at once there could still be huge advantages to having everything contained in one system. pm me, i'd like to see if i could be any help!

Hmm.. I actually don't have much more info than what I've posted here as of yet.. making of course planning this a bit difficult. but yeah any things you are curious about in particular, pm away :)

Ask someone at the institute or faculty in question if they have any vendor deals with anyone that might deal with audio equipment, if they do then contact them as they will give you discounts. If not then you have to find someone else for them(local?) and try to bargain the discounts yourself. Set up a nice description of what you need:

-Minimum 30 mic input mixer/audio interface with firewire/usb output.

-40(10 replacement ones for when they get broken) lapel/lavalier microphones, wireless I assume.

-One hefty computer with a big monitor, lots of memory and a huge raid-setup of disk drives.

It's not unlikely that the UNI has a centralized IT-service that wants all computers on campus to be "standardized", if so you go through them to buy the computer-gear. That's it basically. Contact the retailers and tell them what you need and ask them to make you an offer. The setup is quite simple, issues that come to mind:

-Secure, anti-static, dry housing for the microphones when they are not in use.

-Large storage of batteries if needed.

-Keeping the recording gear away from any of the attendees so they don't mess up the levels etc.

-Decide if they want the recordings to be saved locally or on their network servers and setup backup routines accordingly.

I have probably missed something, but this should be of help.

if you wind up using multiple computers, you will have to devise a device that allows you to press four spacebars at once.

I wouldn't go with multiple computers, just more of a mess.

agreed^