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I am totally new to audio (I'm a visual new media artist and aerospace engineer) so I am damn glad that this site exists. I've already enjoyed listening to the binaural recordings here, and I want to make some of my own.

I want to record binaural sound (on my head), but I also want to monitor the sound through my Etymotic ER-6i headphones, and I am not terribly concerned with sound quality. I have a few questions:

1) Does the fact that I can't have the mics in my ear canal mean that the recording isn't technically "binaural"?
2) Since a real binaural mic set isn't going to work, can I use a pair of small lavalier mics attached to the outside of the headphone body?
3) Is there a simple inexpensive device that acts as a mic preamp *and* a headphones amp? I've seen a number of these that cost $300 and up (like the Maudio Microtrack, which records, too), but I'll solder one first before paying that much. I wouldn't mind using an iAudio U3 to record, but I can't monitor while it's recording.

Thanks for all your help!

Why would you need to monitor the signal so closely if you don't care particularly about the sound quality? No matter what, use a recorder with a good level meter so that you will at least see whether the signal has good level or not. What it sounds like may have to wait until playback.

Two things come to mind.

I have used cheap little headphones (in-ear) as mircophones. Frequencies get a little squished around and most cheap headphones don't sound that great. Try using your etymos AS microphones. Move the cable from the HEadphone out to the mic-in or Linein on your recorder. Because they are so tight fitting, I don't expect this to work that well, but you will certainly hear clearly all the loud sounds that happen to hit your head, and it will be very binaural. (It just wont be 'natural' sounding perhaps, but it will have the proper head placement for sure)
Make sure you do NOT use full phantom power in that configuration I don't think the headphones will like that. I have done this with plug-in power (3.5 - 9v) however and didn't hurt my cheapies, but be more careful of that stuff with good in-ear phones.

You're point 2 will also work, but you have to make sure that what your hearing does not leak out into the mics. Some lav mics clipped onto the side of your head would allow (near)binaural positioning, and if youre using a recorder that can allow you to monitor (Zoom, M-Audio, R-09, iRiver) when you could technically monitor and record at the same time. Any signal interaction though between your mics and headphones could feedback and ruin the recording and/or your ears. I use omni lavs for most binaural stuff, but only when I have the mics actually stuffed into a head (my own or built). Cardioids might be betrte

Build or buy Another Head to mount your mics into. I've made them out of baseball batting helmets, or anything head sized, try to match the density of a skull full of goo. True binaural needs all the ear lobes and canals to be accurate, etc, but basically unless you are using your own head it will never be exact. You could mount your new head on a handle to carry in front of you and monitor whats coming in from the mics with a little more distance to avoid any feedback or unwanted interaction. With this scenario you get less self-noise as well because when you have mics crammed in your ears, you tend to record jaw movements, breathing and other internal functions.

I am not just out to make binaural recordings, I am making an entire "audio filter" between my ear and the world. I need to monitor the sound from the mics because it'll be the only sound I hear---the Etymotics suppress >30 dB---and I'd like to wear this while I'm out and about. I absolutely cannot wait for playback. I'm recording mainly for voice conversations, and I need to be able to hear and record live. This precludes the use of the headphones as mics, and making a dummy head is pointless (and bulky).

I should know if the level is good from the sound in the headphones, right? Or do you mean the post-mic pre-amplifier signal?

The mics that I found (for cheap, the audio-technica ATR35s) have built-in power provided by a watch battery, but quick tests on my computer show that conversations at a distance of 3-4 feet are pretty noisy. The A/C was running in the room at the time, though.

Thanks for the advice about sound from the phones interfering with the mics. I suspect that won't be a problem because of the massive sound suppression provided by the headphones. I clearly couldn't do this with cheap-o iPod phones.

What's the "Zoom"? I've not heard of it. And who makes the R-09? I thought the iRiver recorders couldn't monitor while recording.

I am curious about the self-noise, now that you mention it. This project is becoming righteously weird.

So in summary: the recording will still be at least somewhat "binaural" and I can attach the mics to my ears, though how close to the headphones remains to be determined. I'd still love advice on a cheap record-and-monitor device that can handle stereo MP3.

OK, I found info on the R-09 and Zooms.

Here's what I found: the Zoom H4, Edirol R-04 and R-09 all allow live monitoring. They cost $250, $2k, and $360, respectively. There is no manual out for the H2 yet, so I can't tell whether live monitoring is possible. $200 is much closer to what I can afford for this project, though the 4-channel capability of the H4 might make that a smarter move.

Now, I need to learn a bit more about mics.

I understand now what you're trying to do. Interesting project. I have been trying to wire myself full-time but never found the rig which I can do it with easily, and there are some legalities if it is a conversation that involves you but the other people do not give their consent or those other people can be positively identified by the recording alone. Those are my interpretation of Canadian law. I'm thinking about doing it anyway...

I have an Edirol R-4, it might be a little bulky for your needs, certainly not shirt-pocket sized, you would need a big fanny pack and the batteries will only go so far. Its my favourite unit, but I am plugged in 99% of the time, I take one of my smaller units when full mobility is required.

If you must hear the output, then the headphones you have are designed for your needs. I guess the easiest solution is the mics clipped to the outside of your head approach. And yes, at a distance it will be difficult to discern conversations, you might need some really good highly directional mics, but it will mean pointing your head toward the source and using a good preamp so that its not too noisy if you have to crank it up.

Coresound: http://www.core-sound.com/cardioid/1.php (Stealthy Cardioid mics)
If not in ear-cavity then Omnis will pick up too much of your surrounds and not enough of the 'Subject'
Not sure if anyone makes hyper-cardioid lav mics or not. Even more so though, you would need to tune your position and head placement into the conversation to mask the rest of the noise around you. I don't suppose you want to have two parabolic mics hanging off your head. That would allow you to focus on smaller areas of the environment and potentially pinpoint certain conversations.

The iRiver HP-120/140 will let me monitor while recording. I don't use that at all, so not sure how well. Also the HP120 is a dead product. If you did find one of them, I suggest the free replacement OS from RockBox. A million times better than the built-in software from iRiver. (http://www.rockbox.org/)

You will learn to know if the level is ok, once you get used to the levels you are monitoring. In particular you will hear if they are distorting at all, or if too much wind is getting in. (If you're outdoors, any wind will be a major factor at all times. Make sure you have good foamies or other wind diffusors.) A glance at the level indicators from time to time would also assure you that the signal isn't too quiet or too hot. If you monitor too loudly and suddenly an airhorn or truck horn happens nearby you run the risk of damage.

The 'internal' self-noise I was talking about was specific to using fully in-ear microphones. If you are chewing gum, or even just walking briskly, you can hear the mics rubbing against the inside of the ears, or jaw moment clicks, etc.

I have a Zoom H4 which would handle what you're after. I am even more intrigued by the H2 (Smaller, still has mic input), haven't bought on of those yet. Edirol R-09 is very nice. For very high fidelity: Korg MR-1 ($750-800)

Let us know what you end up with. More importantly, be sure to upload some things to the site for us to here!

Thanks for all the good ideas! Good point about the potential difficulty of omnis for face-to-face conversations.

The legality of such a project is actually one of the more interesting aspects of the project. How much of what we hear and see is copyrighted? Are our memories not our own? What if humans were capable of perfect memory, would copyrights be enforceable at all? When will we reach the boundary between electronic-assisted recording and real brain-like memory?

Well, It goes well beyond copyright as well and into personal privacy and the corporate machine. I wish we could assume that EVERYONE was already recording each other so that people would stop worrying about it. Notice that the police organizations are soon to try and prevent you from recording (mostly video) arrests and whatnot because of the 'trouble' that has caused them on Youtube or whatever. The 'Trouble' usually comes from the Police doing things they're not supposed to, but that hardly seems to matter.

I can't remember the name of the movie I saw on the Documentary Channel, but a cyber-geek made a film about his always-on video system built into his wearable computer and he films himself getting kicked out of Walmart, because only Walmart is allowed to video-tape their customers, and you're not allowed to monitor the monitoring system!!!

Many a movie has been delayed because the camera pan just happens to hit a Home Depot sign or CNN on a TV screen, etc. If you don't have the ability to negotiate or pay monies, you might have to cut that scene right out no matter how integral. It's total bullshit of course. You can't film anywhere in the civilized world and not hit one of those icons.

You're right on target there. The machine will only be exposed once everyone records everything. We must take control of our memories. The benefit to society far outweighs the drawbacks, I believe. Thanks for seeing it. Wish me luck.

UPDATE: I bought the iKey Plus and it arrived today. It works nicely, but I am unable to record stereo signals from the mic. I fear that microphone recording is limited to mono only---a fact that is not mentioned anywhere on the package, on the website, or *anywhere*. I could be wrong. I hope I'm wrong, but I am pissed off right now.

First of all, thank you very kindly for choosing to post back about what you selected. So many people post here with questions and projects and then NEVER think to post again for the benefit of the group....

While listening from the Headphone out, is it *obviously* mono (heard in the centre of your head and equally in both ears) or do you only hear stuff in only one ear no matter what? When you load a file you've made into the computer does it show up as a mono waveform or a stereo one?

I like the basic specs on that unit. In particular the ability to plug into any storage medium; Thats a unique feature for sure. Since the unit is supposed to come with a stereo microphone, there is no way the 1/8" jack is intentionally mono. Is it the supplied mic you are using or a 3rd party?

You could use a separate stereo preamp and plug your microphone into it, using the iKey only to accept the Left and Right RCA inputs instead of 1/8" input. You first need to diagnose the 1/8" jack. If you already have some kind of preamp you can use the idea to eliminate the single plug input.

Please post more detailed info and I'm sure help is available here. Perhaps upload a RAW file downloaded from the unit to Freesound (or email it to me if you like) and certain things can be determined very quickly.

Nice talking to you again. I am interested to hear how your project is going...

Selah.

Selah, thank you for replying so quickly. In my haste I forgot to post details. I hope they help debug the situation.

What think I hear is the same signal going to both ears---the sound seems to be coming directly from the middle of my head. I don't have a waveform editor to see for certain, but some specific tests were illuminating.

The files that are created are 2-channel MP3 or WAV. Sox's "play" program tells me this:
[mstock@bacchus:~]>play iKEY_wav_1.wav

Input Filename : iKEY_wav_1.wav
Sample Size : 16-bits
Sample Encoding: signed (2's complement)
Channels : 2
Sample Rate : 44100

I first put the tiny stereo mic into the mic jack, set everything up, put my Etymotic Research headphones in to monitor, and turned the unit on. When the recording volume is turned all the way up, it is easy to hear myself talk or type. But, when I deliberately touch the foam windscreens (either left or right) I hear the same thing through both ears. I even took one headphone out of my ear to confirm this. This is the strongest indication that the mic jack is mono.

I have not yet plugged a signal source into the dual-channel RCA jacks, so I do not know if the headphone jack is mono. I ran these same tests with my computer as the recording device, and the results were the same, so my computer's mic jack is probably mono also...which is disappointing.

The same thing happens when I tried attaching my two audio-technica ATR35s mics to the iKey, via a 2-mono-1/8"-to-one-stereo-1/8" adapter from Radio Shack. I tested the 2M-1S adapter with a CD and my headphones, and it works as expected.

I would prefer not to have to buy another component (a stereo 2-channel) preamp, mainly because I don't know where to get one that isn't full-on audiophile quality (I just need Radio Shack quality). Although, if I want to add a cell phone and a separate mouth mic to the setup, I would need a (portable) 4ch mixer anyways. Do you have any recommendations for a battery-powered 2ch or 4ch mixer and preamp unit? I've seen things like that for $400 or more. If I could build a simple one I would.

It disappoints me to be fooled into buying this device, though. For another hundred dollars I could have bought the Zoom H4, which specifically states that it has an external stereo mic port.

Here is an MP3 of the above test: http://mark.technolope.org/transfer/testing_ikey_plus.mp3

Well, the iKEY Plus has been revealed as a mono recording device. I am returning mine as soon as I can. I am thinking of picking up the Zoom H-2. It costs $100 more, but I guess that's the price that we have to pay for true portable stereo MP3 recording (or buy two iKEY Plus---not).

This is 'sort of' a solution to what you want to do, I think. The problem is that it lacks the monitoring capability you're looking for.

I have a pair of these soundprofessionals 'in ear' microphones and they totally look like you're just listening to your iPod or whatever, but you're recording. In fact, I used them during a recording studio seminar and sound engineers thought I was listening to the ballgame. It was a small ethical violation, but I had paid for the seminar and didn't pass the recording around. It was my way of taking notes; I mean how do you write down a demonstration of a sound quality that you're supposed to remember?

So check these URLs:

http://www.soundprofessionals.com/cgi-bin/gold/category.cgi?item=SP-TFB-2

http://www.microphonemadness.com/products/mmtrunathook.htm

gezortenplotz
I used them during a recording studio seminar and sound engineers thought I was listening to the ballgame. It was a small ethical violation, but I had paid for the seminar and didn't pass the recording around. It was my way of taking notes; I mean how do you write down a demonstration of a sound quality that you're supposed to remember?

While just having mics in my ears doesn't allow me to turn down the outside world (while turning up the music or a phone call), what you've done with the binaural mics precisely addresses what I want this project to expose: do you own what you hear? And what if we had perfect memory, would our memories then be illegal? Because someday soon, constant video and audio recording about our person will be simple, cheap, and nearly invisible. What then? Do we turn our senses off when we walk into a WalMart?