Binaurals: Sp-tfb-2 Or Mm-bsm-8?

[Stratman]

Hello,

I'm in the market to buy a pair of binaural microphones, I've done my homework and the two which I've been looking at and narrowed the field down to are the Soundprofessionals SP-TFB-2 and Microphone Madness MM-BSM-8. Similar price, similar specs.

The websites:

SoundProfessionals SP-TFB-2

and

Microphone Madness MM-BSM-8

Some things I've heard:

The MM-BSM-8. and the SP-TFB-2 have the same microphone capsules/mic elements. (True/False)

The SP-TFB-2 can be difficult to mount in your ear and the windshields are much tooooo easy to break.

Other things:

I've only been able to find soundclips of the SP-TFB-2 and some of them are really nice.

The MM set appear to have no wind shield???/Are designed to reduce it already?

I'd be using them to record ambience/wildlife and the occasional foley effect for audiodrama material [yes I know these are omni mics, but I have a very quiet room to work with]. I'd be using them with a new HiMD so sensitivity settings aren't a problem.

I'm leaning towards the design of the MM pair, but I'd rather not buy them just to return them [30day money back policy] because for whatever reason they sound or are worse than the Soundprofessional set. If someone could give me some ideas I'd be very greatful.

Stratman

[A440]

I hope Dex Otaku will pick up on this, because he loves his TFB-2's and can probably tell you whether they're uncomfortable.

Meanwhile, you'd probably do fine either way. I once had an email correspondence with Sound Pros and was told (grumpily) that Mic Madness was founded by an ex-Sound Pros employee using similar designs.

You can see the specs for the Panasonic mic capsules on this page (nos. 10-11)

http://dkc3.digikey.com/PDF/T051/1278.pdf

Conceivably one is using WM-61a and the other WM-61b, but that's for them to know.

It looks like the Sound Pros ear mounts are more concerned with stealth, the Mic Madness with strength and comfort, and it doesn't sound like stealth is your priority. Binaurals tend to be more forgiving of wind noise than cardioids, so perhaps MM decided to skip the screens. How windy are the places you're recording?

I hope Dex will have some thoughts, but if not, your preference in mounts should be the deciding factor.

[dex Otaku]

My notes on the TFB-2's:

* I've worn the TFB-2's for up to 6 hours at a stretch with no discomfort. This will depend largely on the shape and size of your pinnae [out ears]; mine are supposedly about average size

* the windscreens are also comfortable, and are durable. They are made from acoustic foam and share the same wear & tear characteristics as most microphone windscreens. There are pretty much acoustically invisible [inaudible?]; they seem to reduce ambience a bit without actually reducing direct HF sources [meaning that off-axis high frequency [HF] sounds are damped, whereas direct ones aren't, which can be handy in certain situations, like when recording outdoors]

* the cabling is durable but is not intended for rough use

* the rubber hooks the capsules are mounted in can be held using anything from standard flat clips intended for use with lapel-type mics to small paperclips [the triangular black kind are what I use]

* the rubber hooks can act as damping from whatever alternate mounting method you use

* because they're earworn, people assume you're wearing earbuds and don't even notice that you can hear them perfectly when they talk to you. This is pretty much the best balance between stealth and sound quality I've ever encountered

* natural ambient sound, when fed through matrix-surround processing, comes out .. really interesting.

cons:

* like any "binaurals", the stereo image depends on how you mount them; earworn recordings are -not- really meant for playback over normal stereos [improper phase alignment for such]

* because they're worn in your ears, you can pretty much assume that "what you hear is what you get". Unfortunately, this includes such things as yourself lighting a cigarette, drinking, and the stereo pespective shiftin or rotating with every single movement you make with your head - something that can be extremely disorienting when listening later

I've found that these mics are excellent and also versatile, given a little ingenuity on the user's part. The sense of space and stereo image are rather spectacular when listening on headphones; with a bit of tweaking they can be made to sound pretty 'normal' over a home stereo. I end up filtering most of my recordings with a 145Hz -12dB, -12dB/oct lowcut because the bass is clean but VERY loud; when listening through headphones everything is very natural-sounding, but through speakers it can end up way too large in the bottom-end.

The biggest single issue I have with them is that of the stereo image rotating when you move your head. I've found that the best way to record with these is to actually meditate while running the recorder; this helps to avoid movement sounds from becoming part of the recording, as well as to maintain a constant perspective for the stereo image.

Stealth vs. quality-wise, I honestly think you can't get much better than these. The biggest caveat is also their biggest selling point: what you hear is what you get.

You aren't shackled to wearing them in your ears, of course. You can pin them to your jacket as I've done with the paperclips a number of times, though I personally don't really like recordings that have been made this way; the stereo image is all weird, using two forward-facing omnis. [This is part of the reason I don't particularly like a lot of the recordings made with glasses- or hat- or jacket-worn omnis.]

What it comes down to is a matter of personal preference, and I would agree that A440's suggestion that mounting method is what should make this decision for you, keeping in mind that while you can use the TFB-2s in virtually all the same ways as any of the other clip-on "binaurals" [which are actual misnamed, since none of them are actually binaural mics], the cabling of the TFB-2s is not as durable as on, say, Reactive's Auris microphones.

I have several recordings made with the TFB-2s online at http://dexotaku.ath.cx .. feel free to download and listen.

Any other questions - please do ask.

[mrtunes]

My notes on the TFB-2's:

hey im new here and i am really curious about these mics too. did you buy the high or low sensitivity, and what model minidisc are you using?

your info was really helpful. thank you

Edited March 15, 2005 by mrtunes

[dex Otaku]

I bought the low sensitivity ones, using them with an NH700 HiMD.

[smkranz]

Based on info from this forum, I bought Sound Pros SP-TFB-2 and went with the hi-sensitivity model, as someone had suggested they'd offer more flexibility since I can adjust the mic sensitivity on the MZ-NH900.

I have been thoroughly pleased with them...the concerts I record sound terrific, like you're right there. Although audience noise (coughing, seat squeaks, etc.) isn't what I necessarily want to hear, those things are part of recording a live concert and these mics do pick up everything, even with the mic sensitivity set to low. However, I'll also say that it brings a smile to my face every time when I'm listening to one of these recordings in my living room, and when I hear someone behind me cough, I actually turn around only to realize (again) that it's in the recording. I am the first to admit that I am easily amused, but the spatial orientation of the recordings I get with these is nothing less than amazing to me.

I cannot say I have noticed any "weirdness" with the stereo imaging coming through home loudspeakers as Dex has described.

They have been very comfortable for me to wear. They just rest in my ear without putting any pressure anywhere in the ear structure which would quickly become uncomfortable. Once you get the orientation down (I used a mirror the first time), they just pop in and out. I have yet to use the windscreens...I tried them on a couple of times, but it felt kinda bulky in there and I felt as though I had to wedge them in a little to keep them from falling out.

[mrtunes]

I bought the low sensitivity ones, using them with an NH700 HiMD.

←

why didnt you chose to get high sensitivity? you seem to do a lot of nature/city stuff. i thought low-sensitivity are the choice of people who are recording loud concernts?

i think i will be using these with the 505 mostly

thanks

[dex Otaku]

I knew I'd be using the mics for a variety of applications, and the few extra dB of undistorted SPL [allowed by the low-sens mic] was more important to me.

[mrtunes]

well this sensitivity decision is the only thing holding me back from buying them. its all because you cant moniter anything that your recording unless you clip them onto your jacket or something which i dont intend on doing.

i want to record people on the street, nature, bus rides etc. maybe some construction sites and stuff. i live in a high traffic area. no concerts or anything like that. should i go for low sensitivity?

[dex Otaku]

The difference between them is actually very small, which is the other part of the reason why I chose the low-sens version.

Going by SP's info:

Signal To Noise Ratio Low Sensitivity 58dB/High Sensitivity 62dB

Open Circuit Sensitivity Low Sensitivity-42dB/High Sensitivity-35dB

Maximum Input Sound Level 105dB/120dB

Dynamic Range 81dB/96dB

I find it interesting that while sensitivity is 7DB higher for the high sens version, and the dynamic range is 15dB higher, the SNR is only 4dB higher.

In the end, I based my decision on the 105dB vs. 120dB max SPL alone. 105dB is enough for small club concerts, for instance, but not enough to record a train engine driving by at a distance of only 1.5 meters.

I think this was probably the right way to go, because ultimately, the only way I'd be able to exploit a 96dB dynamic range would be to lock myself in a soundproof room with a 4000W amplifier and a large speaker stack.

I have never encountered a situation where the actual dynamic range of the recording, from the ambient noise floor of the environment to the loudest sound encountered, was greater than between 60-70dB [and those situations are pretty exceptional, actually, like being 1.5m away from a train driving by at 80km/h in the middle of the country where there's no one and no other traffic around].

I'm probably just confusing this, though.

Let me round it down to this:

If you think you're going to be recording sounds louder than 105dB most often, go with low sens.

If you think you'll more often be recording quiet sounds like birdsong, go with high sens.

[mrtunes]

In the end, I based my decision on the 105dB vs. 120dB max SPL alone.  105dB is enough for small club concerts, for instance, but not enough to record a train engine driving by at a distance of only 1.5 meters. 

I'm probably just confusing this, though.

ha no your not confusing it too much i like a detailed view on things. so let me get this straight: low vs. high sensitivity has a lot to do with change in dynamics rather than the loudness of the sounds around us? when you said that you were in the country with a train going 80 km/h, did this sound clip your mics or are they able to capture the train in general just not when it all of a sudden appears on the meters? i want to use these mics for sound design for film and game type projects. i also plan to use them with more than just minidiscs eventually like DAT. if you keep your head still like you say, you could take care of some really complex panning techniques just by walking around.

[dex Otaku]

so let me get this straight: low vs. high sensitivity has a lot to do with change in dynamics rather than the loudness of the sounds around us? when you said that you were in the country with a train going 80 km/h, did this sound clip your mics or are they able to capture the train in general just not when it all of a sudden appears on the meters?

Well, no. Sensitivity has to do with the efficiency of the microphone at a given SPL. A high-sensitivity mic will put out a greater signal than a low-sensitivity one.

It makes sense that if your sensitivity increases, your dynamic range will as well. If the mic is more efficient but has the same self-noise, the SNR will increase accordingly, and so will the dynamic range.

With my train example - no, the mics never clipped [and neither did the preamp]. Generally speaking, most mics and solid-state preamps don't suffer from problems with transients [when it all of a sudden appears on the meters].

What I was implying when I said the thing about the train was that the train [or at least, the engine] was likely louder than 105dB, in which case the high-sens mics would have distorted.

Side note: if you're recording with the AGC on, -that- is when you'll have problems with those sudden attacks. This is a side-effect of AGC, not of the mics.

I never record important sources, natural sources, music &c. using AGC. I almost always leave AGC turned on for recording speech, though, as it so happens that the low-sensitivity version of the SP-TFB-2s has exactly the right sensitivity for everyday sounds to fall well below the threshold of the AGC's compression, meaning the AGC only kicks in when something really loud happens. Going by the rated sensitivity of the high-sens version, everyday sounds would constantly be riding at or just below said threshold, making the AGC far more obvious.

Perhaps it would help to try and explain what these mean:

Signal To Noise Ratio Low Sensitivity 58dB/High Sensitivity 62dB

Open Circuit Sensitivity Low Sensitivity-42dB/High Sensitivity-35dB

Maximum Input Sound Level 105dB/120dB

Dynamic Range 81dB/96dB

"Open circuit sensitivity" is a measurement of how much level a mic puts out for a given sound level. The current international standard usually uses a reference level of 94dB [1Pa] compared with 1V, i.e. a sensitivity of 0dB would have the microphone putting out 1V when transducing 94dB SPL; if we had mics like that, we wouldn't even need preamps!

See here for a good quick reference to SNR:

http://en.wikipedia.org/wiki/Signal-to-noise_ratio

Likewise for dynamic range:

http://en.wikipedia.org/wiki/Dynamic_range

General audio measurement terminology:

http://en.wikipedia.org/wiki/Audio_system_measurements

While you're there, also check out:

http://en.wikipedia.org/wiki/Microphone and

http://en.wikipedia.org/wiki/Binaural_recording

And, for that matter, the category itself of:

http://en.wikipedia.org/wiki/Category:Audio_engineering

Note that what most companies refer to as "binaural microphones" in fact use variants of the A-B stereo mic'ing technique, and have nothing whatsoever to do with binaural recording; this is part of the reason why I don't actually like listening to many if not most recordings made this way over speakers, and most specifically the reason why I keep insisting on pointing out that most binaural mics are not even pseudo-binaural, let alone binaural. Quoted directly from the wikipedia entry on microphones:

"The A-B technique uses two omnidirectional microphones at an especial distance to each other (20 centimeters up to some meters). Stereo information consists in large time-of-arrival distances and some sound level differences. On playback, with too large A-B the stereo image can be perceived as somewhat unnatural, as if the left and right channel are independent sound sources, without an even spread from left to right. A-B recordings are not so good for mono playback because the time-of-arrival differences can lead to certain frequency components being canceled out and other being amplified, the so-called comb-filtering effect, but the stereo sound can be really convincing. If you use wide A-B for big orchestras, you can fill the center with another microphone. Then you get the famous "Decca tree", which has brought us many good sounding recordings.

[DaikenTana]

I'm thinking of getting an NH700 too, but seeing as it has it's own manual controls, would a Battery Module be worth getting? Would I need to get TSP to put in all the other features for it or just the bass roll off?

[A440]

Would a Battery Module be worth getting? Would I need to get TSP to put in all the other features for it or just the bass roll off?

←

Get the battery module if you want, but don't bother with bass roll-off.

If you are recording anything with significant bass you are going to need either an attenuator (see the top pinned thread in Live Recording) or a battery box, because the mic preamp in the MD unit will overload. The manual controls are not enough to prevent this.

You are better off without bass roll-off entirely. If you are exclusively recording in bass-heavy environments, then conceivably it would be useful. Otherwise you are keeping your recording from having the most fidelity possible--and once that bass has been rolled off, never recorded at all, there is no way to get it back.

Mic-->Attenuator-->Mic-in prevents overload at all but the most ear-bleeding concerts.

Mic-->Battery Box-->Line-in should also prevent overloading (without bass roll-off) but will give you a quieter recording. The Battery Box also allows the mic to record louder sounds without overloading, but in most cases it's not the mic that overloads, it's the mic-in preamp. You're bypassing that by going through Line-in.

[greenmachine]

...and once that bass has been rolled off, prevented from being recorded, there is no way to get it back.

That's somewhat oversimplified, i've tried to explain the effect of different filter orders here. Bass roll-off filters are first order filters.

Mic-->Battery Box-->Line-in should also prevent overloading (without bass roll-off) but will give you a quieter recording.

There is no gap between the lowest mic-in and the highest line-in setting (as i was trying to show in this graph), so why should it be 'quieter'? All you have to do is to find a suitable level setting.

[A440]

OK, greenmachine, it's oversimplified, but you're not a big fan of bass roll-off either.

Anything through mic-in with sensitive microphones, at least with mine (same Panasonic capsules), has the bass overloading problem through the mic preamp, even at low settings. And even the highest line-in settings produce a quiet recording with just a battery box. If there is a "suitable" setting, I haven't found it.

What I don't understand is why I haven't found something between a battery box (not enough amplification) and a preamp (too much amplification, even at minimum) to produce an optimum recording of loud music through line-in. Which is why I'm still using the attenuator and mic-in.

If anybody has that line-in solution, proven in actual use, please tout it here.

[dex Otaku]

What I don't understand is why I haven't found something between a battery box (not enough amplification) and a preamp (too much amplification, even at minimum) to produce an optimum recording of loud music through line-in. Which is why I'm still using the attenuator and mic-in.

Odd, considering the fact that any properly-designed pocket preamp acts exactly as a battbox does when its gain is turned down.

Gerry's toutings about the Reactive Sounds unit, with variable gain rather than fixed with variable attenuation, are accurate IMO. A proper preamp should have variable gain at the input [also acting as actual impedance-matching] rather than attenuation at its output. Such preamps are exactly what you're talking about looking for.

BTW, I experience the same bass distortion with really loud sounds with the SP-TFB-2s. Also, perhaps more interestingly, I find that headphone listening is fine with flat EQ, while speaker listening pretty much -always- requires a low shelf [i usually end up using a -10dB 1st-order filter @ 144Hz].

[dex Otaku]

It makes sense that if your sensitivity increases, your dynamic range will as well.  If the mic is more efficient but has the same self-noise, the SNR will increase accordingly, and so will the dynamic range. 

In a humourous and perhaps bold move on my part, I'm going to disagree with myself.

It would help if I drew graphs for this, but I'm not going to because I'm lazy.

My recent thoughts:

Sensitivity is like a floating point. Dynamic range is perhaps fixed or slightly variable. SNR is as well.

The floating point moves, and the dynamic range and SNR move with it. Hence my thinking that what I said above about it making sense that an increase in sensitivity means a corresponding increase in DR and SNR is bollocks.

Just thought I'd throw that in here.

[DaikenTana]

Thanks for the help fellas. So, for someone like me who is out to do lots of ambience recordings (close traffic, nature, the beach...) would a battery box be more suitable? A440 said the manual controls on the MD aren't enough, so bascially I'd need to have SP put their dual sliders on the battbox too I guess.

Edited June 25, 2005 by DaikenTana

[dex Otaku]

For starter use, if you don't need to record either extremely quiet or extremely loud sounds, the built-in preamp is sufficient.

If you're looking to record things like bird sounds, an external preamp [with a lower noisefloor] would serve you well.

If you're looking to record very loud sounds, there are three methods I'd recommend trying. First, and cheapest, is to use an attenuator between the mic and the mic preamp. Second is to use a battbox and go line-in with it. Third is to use an external preamp with higher bias voltage for the mics [if they need it] and higher headroom.

I have spent the last year recording with a NH700 and SP-TFB-2s, and the only real difficulties I've encountered were as above - when recording birdsong, the noisefloor of the preamp becomes very obvious, and when recording things like artillery fire the built-in preamp gets overloaded. In both cases, my preferred solution would be an external mic preamp with higher bias voltage, more headroom than the built-in, and a lower noisefloor.

Rephrased:

A decent external preamp is the most versatile solution, covering basically all the options, but also the most expensive.

A battbox won't really help for quiet sounds, but will increase the maximum transducible SPL of the mic - which will likely overload the mic preamp, which can be avoided by going line-in [which will mean a quiet signal with all but very loud material].

A passive attenuator [like the radioshack headphone volume control] between the mic and preamp is the least expensive solution for loud material but won't help for anything else.

Hope that made some sense.

[A440]

Dex, please try to stay out of the artillery fire if at all possible.

Daiken Tana: You don't need to get sliders on the battery box. The volume control on the unit or remote is enough, unless you want to vary right and left channel independently.

What I meant about the controls is just that they can't prevent overloading from loud bass via mic-in, because they control the stage after the preamp. Otherwise they are very effective. If you get a battery box you'll be going through line-in and the level control on the MD will be all you need.

And to clarify: I'm talking about amplified bass with sudden attacks, like a kick drum or a bass guitar in a rock band, or a drum kit up close. Quieter music, like a folk group or a barely amplified jazz group, may do just fine directly into mic-in. (Low sensitivity and low manual volume of course.)

If you're doing traffic up close, I would try plain old mic-in first (low sensitivity) and an attenuator if it overloads.

The beach should sound fine through mic-in (try both high and low sensitivity)--the sound of the mic's preamp is a hiss that will get lost in the waves.

Quiet nature sounds, like birdsong, are going to be difficult without a low-noise microphone and possibly a preamp.

But for most ambience recording, mic-in with an eye on the levels should do the job.

[DaikenTana]

Thanks for the help guys! Going over what I can afford and what I'll be doing mostly, I think the BattBox would be the better option for me. My budget at the moment is a bit low, so an NH700, a Battbox and the TFB-2s are all I can currently afford. I might consider getting a Preamp too sometime in the future, depending on how things turn out with the Battbox.

However, I'm still confused as to wether to get a cheap attenuator or a moderately-expensive battery box. From my understanding, the BattBox allows you to change the Mic's volume before it hits the MD and also alter the bass-roll off, while the attenuator can only change the volume. Yet, I've been told that the bass roll off can reduce the fidelty of the recording. So...

http://www.soundprofessionals.com/cgi-bin/...?item=SP-ATEN-1

What about something like this?

Edited June 25, 2005 by DaikenTana

[The Low Volta]

Thanks for the help guys! Going over what I can afford and what I'll be doing mostly, I think the BattBox would be the better option for me.

no, try the cheapest suggestion first: just read above posts again...they don't see a need for a battery box at all unless you want to record really loud rock-shows (not traffic...that would be very quiet when recorded with BattBox). Just use mic->mic in with low mic sensitivity and low enough recording levels, and if it distorts try the cheap attenuator first (the soundpro gadget you found is the same thing)

From my understanding, the BattBox allows you to change the Mic's volume before it hits the MD and also alter the bass-roll off, while the attenuator can only change the volume. Yet, I've been told that the bass roll off can reduce the fidelty of the recording.

if you are mainly going to record rock concerts you could use a batt box and you can buy batt boxes with all functions you describe...but!

- it will only control volume downwards i.e. not amplify the sound so that's useless as BattBox->line in won't be too loud, it would rather be too quiet so don't get this feature

- bass-roll off is mostly considered as the very last option if your recordings (even with a battery box and line in) keep distorting because of the bass... it "blocks" (enormous oversimplification, but easy to understand) the lowest bass (with the best B-R O you can choose up to what frequency) from entering the MD-> this (again oversimplified) means that the bass isn't present in your recording so it can't really be repaired by equalizing and your recording could sound flat so if you can miss the money, you could get this option as a safety, but use it very precautiously...if you don't want to spend the money, don't get this feature as unless on very loud and bassy rock concerts you won't be needing it at all

so recapulating:

- buy the mics and experiment with the settings (manual rec level & mic sensitivity)

- if the loudest sounds clip: get a cheap attenuator and experiment

- if you're not satisfied with the attenuator, get a batt box OR

- if quiet sounds aren't clearly recorded... save up for an external pre-amp which could also function as a batt box

greetings, Volta

[DaikenTana]

Aah I see now, thanks for that Volta. I thought that too; trying the cheapest alternative first. Looks like I'll be getting the TFB-2s and an Attenuator then!

Thanks for all the help, it's much appreciated!

[greenmachine]

I have spent the last year recording with a NH700 and SP-TFB-2s, and the only real difficulties I've encountered were as above - when recording birdsong, the noisefloor of the preamp becomes very obvious,...

←

Not to attack you, but...

how do you know it's not the mics' self noise that you were hearing?

[dex Otaku]

Not to attack you, but...

how do you know it's not the mics' self noise that you were hearing?

←

I don't, actually. And how is that an attack? It's a legimate question.

[greenmachine]

I had the impression that A440 felt offended by my neverending curiosity.

[A440]

Never offended. Curiosity is good.

Daiken Tana:

As the Low Volta said, start with no attenuator at all for ambient sounds.

That Sound Professionals attenuator is exactly the same thing as the Radio Shack headphone volume control, probably manufactured at the same factory in China, and it will cost you twice as much. Only difference is a two-year guarantee, which would be worth something if you didn't have to pay shipping fees--both it and the Radio Shack will probably wear out well before 2 years.

If you are in the UK, Maplin has something similar:

http://www.maplin.co.uk/Free_UK_Delivery/H...ntrol_33144.htm

And Shure also makes something that should work:

http://store.yahoo.com/mm1online/shpaleatfors.html

Don't use the attenuator as a volume control, leave it turned all the way up and use the volume controls on the MD. It's just a cheap way to lower the signal.

[DaikenTana]

Well call me stupid, but where the hell is that RadioShack Attenuator? That link on the thread at the top of the Live Recording category leads to a dead page

[A440]

Here's a new link:

http://www.radioshack.com/product.asp?cata...ct%5Fid=42-2559

Look familiar?

[DaikenTana]

Yeap!

Thanks

[Stratman]

As the terrible person who started this thread, I'd just like to thank Dex and A440 for their replies. I feel I must apologise to, as I've been somewhat busy and didn't mean to sound like I was just posting here to pinch other's thoughts Though, when I last came back this thread had taken on a life of its own!

Just thought I might say that I've decided to buy the MM-BSM-8's and put an order in last week and hopefully they'll arrive intact in the next few days/weeks. I'll probably take them through their paces and see if I can't post some clips here, so that people can have a listen [wherever other MM-BSM-8 users lurk I have no clue].

AFAIK the ones I'm getting will probably have panasonic capsules in them, I couldn't really justify the expenditure that would be involved with buying the Sennheiser ones [if I wanted to do this stuff for money I'd probably imagine I'd have to spring for something more expensive than those even]. Haven't heard any sounds captured with the Sennheiser capsules either, even if they were twice as good as the default ones I'm not sure anyone would be able to demonstrate the fact....

Stratman

Edited July 1, 2005 by Stratman

[m15a]

hi. i'm new to the board. been interested in environmental recording for a while, which led me here. *anyway*, anybody have any experience with the SP-HMC-1 model (http://www.soundprofessionals.com/cgi-bin/gold/item/SP-HMC-1)?

they're outside of the ear instead of inside. i was considering them because i never feel comfortable with the in-ear headphones. can't figure out how they fit or something. also, is there an issue with the pinna filtering? what i mean is if the sound is filtered before recorded by the outer part of your ear and then when you listen to it, it gets filtered again, isn't that an issue?

for that matter, do in-ear *headphones* do filtering to compensate for the fact that the pinna doesn't filter?

thanks a bunch! great to hear there are other people interested in environmental recording. sounds like MD is the way to go as far as recording device, too.

[m15a]

i forgot to say thanks, didn't i?*

*j/k. double posted. sorry.

Edited June 30, 2005 by m15a

[A440]

That's a great question about the outer ear itself as a filter. Dex Otaku has a pair of the in-ears that he sometimes uses outside the ears--maybe he can do a comparison.

It doesn't look like there's room for any filtering circuit on the in-ears, even if it would be possible to compensate for the different shape of everyone's ears.

The headphone mounts are another package for the same basic Panasonic capsule. It's hard to see from the photo where they are actually pointed. It's up to you whether you'd be more comfortable recording with a pair of dummy headphones or a pair of tiny mics and clips.

[dex Otaku]

That's a great question about the outer ear itself as a filter. Dex Otaku has a pair of the in-ears that he sometimes uses outside the ears--maybe he can do a comparison.

The overall fidelity of the mics isn't .. hmm. how to say this. The mics themselves have the same response curve regardless of where they're mounted, but that doesn't mean that what reaches them is the same regardless of where they're mounted.

When you wear them in your ears, your ears and head actually EQ the sound reaching the mics. This wouldn't be true HRTF-type stuff, but it does make a difference with headphone listening, as the shape of your pinnae, the size of your head, and even the shape and size of your torso all affect the sound reaching the mics themselves.

Note that regardless of where and how the mics are mounted, the same thing happens. If you mount mics on the temples of your glasses, to a hat bill, or pin them to your shirt or jacket, the same thing's happening - the mounting surface is occluding sound from certain directions, adding reflection and absorption characteristics of its own.

The key difference is that you're applying a very specific kind of "profile" to the sound when they're in your ears. I have tried recording with my mics in someone else's ears, and the difference when listening is immediately obvious.

So - to sort-of answer the question - no,the mics are not EQ'd differently [assuming that the capsules are identical] but where you mount them does make a difference - as is the case for all microphones in all mounting situations.

The SP-TFB-2s work as any other paired omnis. The only difference is that they're molded into soft plastic hooks for wearing in your ears. Mounting them as you would any other pair omnis gives you the same effect as using any other pair of omnis.

It doesn't look like there's room for any filtering circuit on the in-ears, even if it would be possible to compensate for the different shape of everyone's ears.

Considering the fact that the SP-TFB-2s are made for binaural recording, EQing them to compensate for the difference incurred by your ears [which is different for every wearer, though there are average curves that can be applied, sure] would be entirely counterproductive. The whole idea in the first place is to use the "profile" caused by your ears, head, and upper body for a particular effect, that of binaural recording. That said, the mics themselves should be as sonically neutral as possible.

This is part of why I take issue with companies that call their mics binaural, when the only 'real' binaural mics are either earworn or mounted in a dummy head. Just because they're paired omnis doesn't make them actually binaural in any way, shape, or form. Binaural is a particular recording technique and depends on the mics being mounted in a pretty specific way, which I just mentioned the two primary variations of.

[m15a]

okay. i think i got a little lost in those past couple posts, so maybe my questions have been answered already . . but you say that there's a clear difference when you listen to a recording from someone else's ears, since they filter the sound differently. wouldn't it be in some ways better to record from over the ear and then have the user listen on out of ear headphones? that way, the sound will be filtered using the listener's pinnae, which will be maybe more natural, while maintaining a lot of the binaural effect (that is, the filtering from the head/body which doesn't occur when listening to sounds on headphones).

also, am i write in thinking that if you record with in ear binaural mics and then listen to the recording with over-the-ear headphones, it will sound incorrect . . like the sound will be filtered through two sets of pinnae? (and i suppose listening to an over-the-ear recording with in-ear headphones would be bad, too, since this will have no pinna filtering.)

thanks again for your responses!

btw, if anyone's interested in ear filtering, i did some research work with it a few summers back. actually, it was about simulating the ear's filters for sound quality analysis. i can dig up the paper in the off chance there's a request.

[dex Otaku]

okay. i think i got a little lost in those past couple posts, so maybe my questions have been answered already . . but you say that there's a clear difference when you listen to a recording from someone else's ears, since they filter the sound differently. wouldn't it be in some ways better to record from over the ear and then have the user listen on out of ear headphones? that way, the sound will be filtered using the listener's pinnae, which will be maybe more natural, while maintaining a lot of the binaural effect (that is, the filtering from the head/body which doesn't occur when listening to sounds on headphones).

Opinion: the combination of occlusion effects, naturally-imposed EQ &c. that are caused by the recordist's head and body, and the positioning of the mics [ear-distance apart, facing out at nearly 180 degrees from each other] are specifically what make the binaural recording sound the way it does.

The difference from recordist to recordist is noticable but only in the same way that A-B mic'ing sounds different when you space or orient the mics differently. It's not like someone taking an EQ and cranking certain bands and cutting others; it's more that the mics are in a different position, so phasing is slightly different, as well as overall EQ because of things like the recordist's size.

What you're suggesting seems more to me like the difference between close-mic'ing an instrument in a reverberant space, and distant-mic'ing it. If you close-mic the instrument, it sounds pretty dead when played back, so you add reverb to it to make it sound more "natural". If you distant-mic the instrument, the recording already contains the reverb and needs no processing.

This is not to say that either of us is right or wrong. I'm just saying that IMO an actual binaural recording should be "processed" that way -before- the material hits tape [so to speak]. [by "processed" I mean that the effects caused by the recordist's body / the dummy's head+torso should be present in the recording when it's being made for it to be considered binaural].

Still, this is my opinion, not the word of Bob. [read more Douglas Adams if you don't get the 'Bob' reference.] I'm not a professional audio engineer [in the actual engineer sense], nor am I formally trained on any of this. These are the conclusions I've come to on my own, so I might very well be out to lunch on it, though it makes sense to me.

In the end all that really matters is that the recordings either sound good or bad, hopefully good, whichever way things actually work.

also, am i write in thinking that if you record with in ear binaural mics and then listen to the recording with over-the-ear headphones, it will sound incorrect . . like the sound will be filtered through two sets of pinnae? (and i suppose listening to an over-the-ear recording with in-ear headphones would be bad, too, since this will have no pinna filtering.)

You might be right on this one [i think you are], but I don't recall which way it swings. I know that headphones are generally EQ'd to either compliment or cancel the "average" curve of human hearing at the pinna - basically, to compliment or cancel the binaural effect. Unfortunately, I don't recall which it is. The idea is that the signal reaching the mechanics of your ear should be flat, so I'd think that circumaural 'phones would likely be cancelling it.

I do know that some 'phones claim to be made "for binaural listening" where the vast majority are not [or at least don't mention it]. The only ones I've seen that mention this are canalphones, so it might make sense that circumaural 'phones are compensating to cancel the same effect.

I don't really know.

What I do know is that recordings made with these mics sound perfectly fine over every pair of 'phones [and I mean circumaural 'phones] I've tried them with - they sound "natural", whatever that is. Playback over speakers, though, often sounds, well, like crap unless you EQ the signal [bass rolloff]. On 'phones you don't even notice that there might be an imbalance of some kind, whereas over speakers, the bottom octave is almost explosively loud throughout. This might just be the response curve of the mics, and it might be treble-filtering from my pinnae, or maybe it's both.

thanks again for your responses! 

You're welcome. Discussion is good.

btw, if anyone's interested in ear filtering, i did some research work with it a few summers back. actually, it was about simulating the ear's filters for sound quality analysis. i can dig up the paper in the off chance there's a request.

Sure. I've done some reading on HRTF processing, mostly by a Spanish or Italian gentleman whose name I don't recall, who designed dummy-head/torso systems for evaluating sound which have been since used by car manufacturers and such for acoustic analysis.

[A440]

  On 'phones you don't even notice that there might be an imbalance of some kind, whereas over speakers, the bottom octave is almost explosively loud throughout.  This might just be the response curve of the mics, and it might be treble-filtering from my pinnae, or maybe it's both.

←

This is interesting to me for two reasons:

1) It suggests the in-ear phones may not be picking up all the high-frequency info that the mics would if they were in the open air.

2) Canalphones (I have and love the Shure E3) are notorious for underplayed bass response. Perhaps they are deliberately EQ'd that way.

And an idle thought: When I'm trying to hear more vocals in a bottom-heavy club mix, I usually tilt the back of my pinnae forward, which boosts the treble.

[dex Otaku]

1) It suggests the in-ear phones may not be picking up all the high-frequency info that the mics would if they were in the open air.

This makes sense, as the pinnae "shape" the sound differently as it comes from different directions. This is integral to what I'd call the binaural effect.

Part of the purpose of your pinnae are to focus the sound coming from different directions in different ways; this includes tiny alterations in phase and level that are different from every direction at every audible frequency. The 'average' of parts of this are what give us information like the Fletcher-Munson curves. Those differences caused by [among other things] the pinnae are central to how we perceive direction and distance, depending on the brain's ability to differeniate between the same source sounding different at each ear. This is much like the aural equivalent of how binocular vision works.

2) Canalphones (I have and love the Shure E3) are notorious for underplayed bass response. Perhaps they are deliberately  EQ'd that way.

I believe it was on Etymotics site that I read the notes about "made for binaural listening". If I have time I'll go looking for it again.

And an idle thought: When I'm trying to hear more vocals in a bottom-heavy  club mix, I usually tilt the back of my pinnae forward, which boosts the treble.

It boosts the -reflection- of treble coming from in front of you. You're refocusing the sound is what you're doing, just like cupping your hand behind your pinna[e] is much like using a parabolic mic [your hand is the parabole].

Looks like a listening/recording test is coming up.