Buzz buzz buzz in the drum of the ear

February 16, 2010 3:04 PM

I record university lectures for podcasting, but I'm finding I can't rely on plugging in to the lecture hall audio system to get a clean recording. Given I have a digital field recorder with XLR inputs, what sorts of equipment (mics, mixer, etc.) could I pick up for $500 total that could allow me to make a decent recording of a lecture?

First thing to note: I don't know much about audio. I record things, I clean them up in Audacity, I dump them to MP3s, and I update our podcast feed. The process of recording audio I don't have a lot of knowledge of, other than what I've learned by trial and error in recording 30+ lectures the last 3 years.

I have a Marantz PMD660 and have been using a 1/4"-1/8" cable to plug into the board out in lecture halls. What I'm discovering, though, is that either the jack has been turned off (with no one in the A/V knowing how to turn it back on), or the equipment is so old that I get a lot of static. The last recording was a sea of static and buzz.

I could set the recorder on the podium and used the internal condenser mics, and I've done so in the past, but not only do omnidirectional mics pick up every last squeak and cough and "this lecture sucks" in the room, they also don't work well when the lecturer is on a lavalier and is walking all over the whole dang room.

The last three recordings I've made have been absolutely rotten. Something has to change.

The org seems to be okay with the idea of upgrading the equipment. I want to float $1000 and $500 spending proposals for buying more equipment. Due to budget constraints, though, I'm assuming that $500 is what I'll probably end up with.

So. I have a battery-powered field recorder with XLR and 1/8" inputs. I need to effectively, though not perfectly, record lecturers without pulling in too much ambient or crowd noise. I also can't assume that I can just unplug the lavalier and plug mine in -- I don't want to dink with the current setup.

I would also like to be able to do two-mike interviews eventually, so I'll need a mixer or a board. Again, this isn't high-end stuff -- the MP3s will be 32-64kbps mono.

Any ideas? Is $500 too low, and if so, what should I ask for if I can talk them into a $1000 upgrade?

posted by dw to media & arts (11 answers total)

PS: Getting a laptop and going all USB won't work, either. No laptop available to me in the office that I can commandeer for recording (it's already being used for the presentation slides).
posted by dw at 3:07 PM on February 16, 2010

My husband uses a Zoom H2, and loves the sound quality. Very easy to use and easy to transfer to his desktop. He paid about $200 from Musicians Friend, he thinks.
posted by raisingsand at 3:28 PM on February 16, 2010

I wonder if you are making this too complicated. I have found that using the Profcast software I can use the same laptop to both project slides and record audio, and on my laptop (an old iBook) I haven't found the need to have any kind of separate mic, despite moving around the front of the lecture room (perhaps if you really walk around the whole room this might be a problem). This also has the advantage that the output is a movie file with the slide transitions coordinated with the audio track, rather than producing just an audio track.
posted by Jabberwocky at 3:28 PM on February 16, 2010

You just need a shotgun mic. They're designed specifically to record say a speaker that is sort of far away with out getting all the room noise. Your marantz is a great machine - you just need a quality shotgun.
posted by Lutoslawski at 3:32 PM on February 16, 2010

Can you ask the lecturer to wear another lavalier? If you can, then a quality lavalier and transmitter/receiver set should solve your problems (except that if something goes wrong, only you, who are presumably sitting there monitoring, will know). Otherwise, if you don't want to record the whole hall, but the person you want to record may move around in the hall and face different directions, you are pretty much out of luck (assuming that following the lecturer around is out of the question). The only other option would be to tap into the existing mic signal before it reaches the hall's board, which I'd assume you wouldn't be allowed to do (as you'd be dinking with the current setup).

As soon as I saw this question, I wanted to recommend a nice shotgun mic, like Lutoslawski, but if your lecturer is walking all over the room, that just won't work unless you are willing to spend the whole lecture aiming the mic (and even then you'll have highly varied sound quality from the times when the lecturer was facing away from you, etc.).
posted by ssg at 3:50 PM on February 16, 2010

Seconding Lutoslawski. I use your machine to conduct public radio interviews for broadcast, and I pair it with an Audio Technica 835B shotgun mic. I bought mine from Sweetwater for about 250, they also have sales on them frequently. When I need sound from a lecture, I never use line out, mainly for the reasons you described.

I don't know what a lavalier is, but if you do decide to go the shotgun route, you'll either want to mount it and ask the lecturer not to walk around, or follow them around and point it about 2 inches from their mouth. Also, if the lecture is being broadcast on speakers in the room, you can get surprisingly OK sound by just pointing the shotgun mic at the speakers.

Last thing, you can do a 2 mic interview using just that Marantz kit. You plug one mic into the XLR input and one into the line in input. It works fine.
posted by WStraub at 3:50 PM on February 16, 2010

but if your lecturer is walking all over the room

Doh. Didn't think about that. I would tell them to either try and stand still-ish (they don't have to not move, they just have to not be pacing faster than you can aim) - or do exactly what WStraub said and follow them around. One thing I've learned in doing field recording for radio, is that as awkward as it is, don't be afraid to really get up in there to whomever you're recording. All other hacks aside, it really is the best way to get good sound quality.
posted by Lutoslawski at 4:09 PM on February 16, 2010

A board feed would certainly be simpler. Can you provide make/model on the gear involved? If there's an output available, a feed should be possible, it might just be that something isn't set right.

If you DO have to go with some additional gear, the AT 875 is a nice short shotgun and is usually under $200. That along with a basic shockmount and a basic mic stand should cover you for a stationary lecturer.

If they're on a lav, micing one of the speaker cabinets can work. A dynamic like an SM57 or 58 might be a safer bet there if the speakers are loud. A 57/58 should run you $100US or so. There are a ton of counterfeits out there so don't fall for someone selling them for $50.

For recording interviews, you can just wire two mics to the Marantz's XLR inputs and set the level for each one, no need for a mixer.
posted by jjb at 4:13 PM on February 16, 2010

Isolating the speaker from the crowd is only partially about the mic - There's also placement, which is a whole arcane art in and of itself - One that some people make very lucrative careers out of... $20 on a book would probably be money well spent, even if it's your own. As John Muir said 'Come to kindly terms with your ass, for it bears you'. :)

Going to agree with jjb above - two separate feeds, particularly if you're going to post-process - You can cherry-pick back and forth to get the best audio.

I pretty much disagree with the whole shotgun mike thing - If the lecturer(s) are stationary, this is an answered problem - Use a properly oriented and isolatedboundry/PZM microphone(*). In my experience, if the speaker is mobile, a shotgun is basically worthless - Trying to get a consistant level out of one while keeping the handling noise down to a dull roar is going to drive you to drink, and you're going to be pretty conspicuous/distracting doing it - You want a solution that works, not one that you have to work. **

If the audio speakers in your auditorium use 1/4" outputs or similar, you might want to look at a Direct Interface box***, that will let you loop their speaker output through it and sip off, which bypasses most of the feed issues. If the speaker works, you get what it gets, without a conspicuous mic sitting there waiting to get bumped/fall off/etc. You mentioned the last feed recording being a 'sea of buzz' - This is sometimes a sign of a grounding problem, which running through a DI may fix. Much, much more on debugging line level problems in the book above.

* Not a model recommendation. Don't worry about the 'phantom power' thing they talk about: your deck supplies it.
** If you do this (Don't do it. Really. ), bring along a pair of high isolation headphones so you can monitor the feed from the shotgun, or you might be in for some very unpleasant surprises when you pull the audio later.
*** This IS a recommendation - This model does line AND speaker level, and the last one I used was one of the most trouble-free pieces of gear I've ever seen. Also Phantom powered, and your deck will drive it.
posted by Orb2069 at 5:21 PM on February 16, 2010 [3 favorites]

the Profcast software

I'd never heard of it, but that could solve another problem I've been having (with people begging for slides + audio). OTOH, that laptop is 2003-era Dell and has only onboard sound....

Can you ask the lecturer to wear another lavalier?

Possibly, if it doesn't cause interference. I should note the lavalier isn't one of those little lapel lavaliers but one of those old-school ones you hang around your neck. A/V equipment just isn't a high priority here.

you'll either want to mount it and ask the lecturer not to walk around, or follow them around and point it about 2 inches from their mouth.

In the middle of a lecture? Really? That's a massive distraction.

I'm sensing a shotgun mic isn't the solution.

A board feed would certainly be simpler. Can you provide make/model on the gear involved?

There are (I think) fifteen lecture halls with A/V in this building, each with equipment installed at different points over the last 60 years. The last lecture hall I recorded in, the one that was the breaking point leading to this question, had a sound system that looked like it dated from the early 70s. I've reached the point where I can't trust the local equipment.

If they're on a lav, micing one of the speaker cabinets can work.

Ceiling mounted speakers for the most part in the halls.

For recording interviews, you can just wire two mics to the Marantz's XLR inputs and set the level for each one, no need for a mixer.

Of course. Why didn't I think of that?

If the lecturer(s) are stationary, this is an answered problem - Use a properly oriented and isolatedboundry/PZM microphone(*).

OK, this makes sense. I'll start looking in this direction -- and pick up the book you recommended.
posted by dw at 2:30 PM on February 17, 2010

If the lavs the lecturers wear connect to the sound systems via XLR, you could use something like this to split the feed without having to worry about phantom power issues messing with you.
posted by jjb at 1:45 PM on February 18, 2010