Lecture Recording Tricks

[Crescend]

The semester is starting soon, and this time I’m prepared. Because I learn far better by listening than by reading, I intend to record my lectures. However, because I’ve a tendency to overengineer anything I do, I’ve been thinking about how to get the best, clearest recording, without actually changing anything but my own equipment.

My equipment: A Samson Zoom H4 digital recorder. Two electret condensers built in, two 48V XLR jacks in the base, for a total of 4 channels. The H4 can record at up to 96kHz/24bit (Although I’ll be using 48kHz). I can borrow various gear to connect to these jacks.

The room: A lecture hall two floors tall, with room for approximately 150 people. The hall slopes sharply upwards, making the knees of someone sitting on one tier of seats be approximately head-level with a person in the tier directly in front. Decent acoustics. Two large speakers, one on either side of the room near the ceiling, roughly 1/3 of the way from the lectern at the bottom of the hall to the back, pointing downwards and toward the center of the room.

The lecturer: Wireless lavalier microphone system (make/model currently indeterminate, will find out later).

Any ideas on how to use this equipment to squeeze the best sound possible from the space? Get shotgun mics and point them at the speakers? Point the built-in condensers at the lecturer? Find out the exact channel the lavalier system works on and get a receiver for it? Point the condensers at the ceiling to catch reflected sound? And finally, any ideas about how to filter out the noise of my fellow students?

Is there a sound engineer in the house?

[Santo_Rugger]

Any chance you can hook up in-line? Somewhere between the mic and the speakers?

[Oakminster]

First get permission from the lecturer.

[Crescend]

@Pygmy Rugger

Any chance you can hook up in-line? Somewhere between the mic and the speakers?

If there’s no way to get acceptable quality via non-invasive methods, I’ll ask for a hook-in. However, I’d much prefer not having to touch the existing setup at all.

@Oakminster

First get permission from the lecturer.

Of course.

[Mangetout]

I’ve managed to get very acceptable recordings of spoken material using just my Palm Treo (using a freeware app called SoundRec) - in cases where a bit of ambient interference (i.e. people near me shuffling papers, coughing etc) is expected, I just arranged the fabric of a jacket in a very rough half-cone covering the recording device and with the open end pointing toward the sound source I wished to record. Low tech, but perfectly serviceable in situations where no easy alternative was viable.

[Ignatz]

Reminds me of a movie, I think it was the 1983 flick, Class, with Rob Lowe, Andrew McCarthy, and Jacqueline Bissett, in which, on the first day of class, one enterprising student put a tape recorder (large size then) on his desk to record the lecture, in absentia. The second day tere were a dozen such recorders on students’ desks, without those students being there. The third day all of the students desks had recorders, with no students, and there, at the front of the room, was a recorder, giving the lecture, sans professor. If was priceless.

[Musicat]

Sound engineer here, at least at a semi-pro level. Your biggest problem is echo. The best way would be to hook into the PA system electronically, but that is unlikely to be allowed unless the lecturer is part of your family or they make it available to all students (maybe in the future, an audio & AC socket at each desk?).

Next, your idea of getting a wireless receiver is pretty good. You’d have to match the channel and probably the brand of transmitter, and hope they aren’t trying anything cute like encryption or pilot tones (probably not, and if they are, maybe you can convince them to turn it off). But wireless receivers are expensive, and you might have to spend a few hundred $. Being able to sit anywhere in the hall is a plus (wireless audio units carry hundreds of feet in open air).

Then, a shotgun or directional mike pointed at, and closest to, a speaker (the hardware, not the person) would be pretty good. Try to cushion it so it doesn’t pick up noises from your desk or chair, and hope that no one talks near you. Get a seat near the speaker. A shotgun will minimize room echo. One additional advantage is if someone in the audience speaks and you want to pick them up, too, you can point the mic at them. A lav mic on the lecturer won’t work for them.

Only if you can sit very close to the lecturer and very far from a speaker would you want to point a mic at the person himself, and that is actually harder to do if the lecturer walks around. At least a mic pointed at the speaker won’t have to be moved even if the lecturer does.

I have a shotgun mic I love, Audio-Technica ATR55, which costs about $60. It might be overkill for you, and it might be bigger than you want, but shotguns tend not to be small. It has both a tele and a normal position.

If you can sit really close to a speaker, just use the cheapest, smallest mic you can get, but I am talking about less than 3 feet, probably not doable in your case if the speakers are on the ceiling.

Point the condensers at the ceiling to catch reflected sound?

Definitely not. All you will get is echo. All reflected sound is muddy compared with the direct sound. It’s a good effect for music, but no good for voice clarity.

[Dewey_Finn]

@Ignatz

Reminds me of a movie, I think it was the 1983 flick, Class, with Rob Lowe, Andrew McCarthy, and Jacqueline Bissett, in which, on the first day of class, one enterprising student put a tape recorder (large size then) on his desk to record the lecture, in absentia. The second day tere were a dozen such recorders on students’ desks, without those students being there. The third day all of the students desks had recorders, with no students, and there, at the front of the room, was a recorder, giving the lecture, sans professor. If was priceless.

I thought of that too, except I think it was the Val Kilmer film “Real Genius.”

[Musicat]

@Ignatz

Reminds me of a movie…The third day all of the students desks had recorders, with no students, and there, at the front of the room, was a recorder, giving the lecture, sans professor. If was priceless.

Reminds me of my favorite definition of a college lecture: “Where the data is passed from the notebook of the professor to the notebooks of the students without passing through the minds of either.”

[Crescend]

@Musicat

Next, your idea of getting a wireless receiver is pretty good. You’d have to match the channel and probably the brand of transmitter, and hope they aren’t trying anything cute like encryption or pilot tones (probably not, and if they are, maybe you can convince them to turn it off). But wireless receivers are expensive, and you might have to spend a few hundred $. Being able to sit anywhere in the hall is a plus (wireless audio units carry hundreds of feet in open air).

That reminds me. After a considerable amount of reading, I still can’t figure out if there’s any real interoperability between wireless mic systems. I know that they have a general band that they’re supposed to operate in (mostly UHF now, old units used VHF). But will one manufacturer’s receiver pick up another manufacturer’s transmitter with any degree of reliability? Would a general-purpose scanner radio do the trick? Or is it really a matter of matching hardware?

@Musicat

Then, a shotgun or directional mike pointed at, and closest to, a speaker (the hardware, not the person) would be pretty good. Try to cushion it so it doesn’t pick up noises from your desk or chair, and hope that no one talks near you. Get a seat near the speaker. A shotgun will minimize room echo. One additional advantage is if someone in the audience speaks and you want to pick them up, too, you can point the mic at them. A lav mic on the lecturer won’t work for them.

I’ll probably end up doing this, unless I can quickly make friends with someone in the RF engineering department.

[Khampelf]

@Dewey Finn

I thought of that too, except I think it was the Val Kilmer film “Real Genius.”

I’ve seen Real Genius, and remember the scene, but haven’t seen Class. Maybe it’s in both movies?

[capybara]

I recognize it from Real Genius.

Back to the OP-- as a lecturer, the thought you’re putting into this interests me. For one particular room? Are you a "returning student’, or a particularly techy dork? You seem very serious (not slagging-- this shows admirable initiative and investment).
I’ve just had students stick their recorders up on the podium, and that seems to work ok.

[Crescend]

@capybara

Back to the OP-- as a lecturer, the thought you’re putting into this interests me. For one particular room? Are you a "returning student’, or a particularly techy dork? You seem very serious (not slagging-- this shows admirable initiative and investment).

I’m a med student, and all medical lectures are held in the same auditorium; this setup will be good for all classes to come. As for the effort I’m putting into this, that’s partially because I want to truly master the material, partially because the courses this semester are some of the most difficult in the entire curriculum, and partially because, as I said earlier, I tend to overengineer all of my solutions.

…they sad I was mad, but I’ll show them - I’ll show them ALL!

cough

@capybara

I’ve just had students stick their recorders up on the podium, and that seems to work ok.

Unfortunately, there’s no real “podium” here, nor is there a stage. There’s a big A/V console, and most professors just walk around across the front of the hall. (By “front”, I mean “the space at the bottom of the pit”. The auditorium is very, very sharply sloped up.) That space is both too large for my mics to adequately pick up the professor’s unamplified voice, and in a bad position for the amplified voice to reach the recorder there.

[Musicat]

@Crescend

That reminds me. After a considerable amount of reading, I still can’t figure out if there’s any real interoperability between wireless mic systems. I know that they have a general band that they’re supposed to operate in (mostly UHF now, old units used VHF). But will one manufacturer’s receiver pick up another manufacturer’s transmitter with any degree of reliability? Would a general-purpose scanner radio do the trick? Or is it really a matter of matching hardware?

I’m really not sure, which is why I suggest you grab the transmitter the lecturer is using and write down the model number for starters. If it is a current model, get a receiver from an audio/video house to match; if an older one, you might have to go to the used market or eBay.

A scanner would be overkill, since the freqs are usually written on the unit or shown on a display. I’m not sure about combining diff manufacturer’s products.

The newest wireless sets have multiple frequencies, but most non-pros just stick with the default settings unless they experience interference. If your receiver doesn’t work, you’ll have to read the freq from the transmitter and match it.

Having a tech geek around can make this simplier, and there’s always the possibility that the admin dept, for security reasons, insists on using some features like pilot tones, which can lock out all but one receiver, and you’re out of luck and bucks.

If Cartooniverse is around, maybe he can add some to this discussion, as he is a video expert.

Just a thought – that’s a pretty good recorder you plan to use, and tho normally I would say avoid built-in mics for fidelity reasons, in this case, it might be a lot easier if they will work. You might just give it a try, but again, get as close to the speaker as you can to minimize room echo. And recording to MP3 should be fine for voice.

[ethelbert]

Ask if they accommodate the hearing impaired with earphones. Record from the earphones.

[threemae]

@Crescend

I’m a med student, and all medical lectures are held in the same auditorium; this setup will be good for all classes to come. As for the effort I’m putting into this, that’s partially because I want to truly master the material, partially because the courses this semester are some of the most difficult in the entire curriculum

Uh, med school? Come on, you don’t even need to go to class, let alone record the damn lectures.

[Crescend]

@threemae

Uh, med school? Come on, you don’t even need to go to class, let alone record the damn lectures.

Like I said, I get a lot more from listening than I do from reading. If I don’t go to lecture, I’ll just end up reading the material aloud to myself. This way, I need to study much less.

And thanks for the advice, everyone - the A/V people were sympathetic to the cause and allowed me to patch in directly.

[Santo_Rugger]

@Crescend

Like I said, I get a lot more from listening than I do from reading. If I don’t go to lecture, I’ll just end up reading the material aloud to myself. This way, I need to study much less.

And thanks for the advice, everyone - the A/V people were sympathetic to the cause and allowed me to patch in directly.

I think he was joking.

Woo whoo, looks like I was right the first time!

[Crescend]

@Pygmy Rugger

I think he was joking.

Color me whooshed, then.

[Musicat]

@Crescend

And thanks for the advice, everyone - the A/V people were sympathetic to the cause and allowed me to patch in directly.

There ya go! That’s the best of all. Just make sure your recorder can handle the levels – that’s probably a line level out from their system, which is jucier than a mic level. If your recorder has a “line in” separate from a “mic in”, that might be the best input. Too high a level will give you distorted sound.