Need Suggestions For Capturing Train Audio
 

Hi All,
I need some real advice to a very vexing problem. I like to record trains climbing hills. I am using a Panasonic HMC40 with a Panasonic AG-MYA30G XLR adapter and an AT 875R mic. The problem is capturing good audio while the train is at distance, yet not distorting when it gets close. I have tried all manner of settings, from using the limiter built into the camera along with my best guess, to setting different levels for each channel and blending the two later. But every location is different, with differing locomotives and distances from them.
The most frustrating part to this is that I have a small Sanyo xacti I carry in my pocket, and with it set on auto it does a wonderful job of capturing both distant and close up sound. Much better than the Panasonic and attachments. From what I can gather the Sanyo has Auto Gain and the Panasonic doesn't. I'd really like to make the Panasonic work as I like the camera itself, but I'd be open to suggestions of another camera if it would cure my problem. Also I'd appreciate any other advice on solving this problem. I'm open to changing any of the equipment but have no clue where to start. Can I buy a unit that would do Automatic Gain? I feel the sound I get is lacking in higher frequencies, but that just may be me.
I've added links to audio clips recorded by the two cameras. Thanks for any help.
Scott

http://dl.dropbox.com/u/19575495/sou...0panasonic.wav
http://dl.dropbox.com/u/19575495/sou...st%20sanyo.wav

Re: Need Suggestions For Capturing Train Audio
 

I haven't listened to trains close up since I was about 15, so I can't assess the "realism" of your two files. But let's talk about audio in general.

First off, what's the closest distance between you and the train? The 875R has a fairly narrow pickup pattern, which would be fine if the train is a mile away. But when the train gets close, since that mic is fairly directional, you won't get a good representation of the entire "sound stage." A cardioid, or better yet an omni, will sound more realistic if you're really close. (And of course a mono track from a single mic won't sound as realistic as a stereo recording, all other things being equal. I really think stereo would be important here, as the train moves across the frame, from one side to the other.)

I hear significant AGC in the Sanyo track. For example, when the whistle blows (around 17.3 to 18.8 seconds), the sounds of the engine become significantly softer, then when the whistle stops, the engine sound gradually comes back up in level. To my ear, that makes the Sanyo track terribly unrealistic. Another example: as the engine goes past, the level in the Panasonic track goes up, then down, reflecting the changing distance between engine and mic. In the Sanyo track, the level stays fairly constant (because of the AGC); it would not sound like that in real life.

The latter part of the Panasonic track, from about 1:36 to 2:00, does seem to have a pretty constant level. I wonder whether the camera's ALC is kicking in at that point, to prevent clipping. You might want to back off on the record gain by 6dB or so, to avoid that situation.

I don't particularly hear any overload or clipping in your tracks, nor do I see any in the waveforms. Do you think you hear any significant distortion? If so, what point in the time line? The 875R can supposedly handle 127dB SPL; I doubt that you're experiencing levels higher than that (or you would be experiencing severe physical pain).

I do notice a difference in frequency spectrum between the two recordings. Levels are similar up to around 300 Hz. Above that, the Sanyo has more level than the Panasonic, by roughly 6 to 12 dB. The difference is even more pronounced above 10 kHz. Since I don't know which model xacti you were using, I can't look up specs, so I can't really account for that. Again, since I don't have the sound of that train "in my head" I can't really say which track sounds more "realistic" to me. (The Sanyo track, with more HF, might be more "interesting" but maybe that's not actually realistic.)

I'd suggest you search for specs on your particular model xacti, and see if you can find out anything about the frequency response. If there is any kind of gradual LF rolloff available on the Panasonic, you might try that, in an effort to get the frequency spectrum closer to the xacti, if you prefer that sound.

Otherwise, hopefully someone who has experience with the HMC40 will step in with some suggestions.

Re: Need Suggestions For Capturing Train Audio
 

I wonder would it be possible to capture more of the low frequencies associated with the train, say with some type of boundary mic on a cross-tie, etc?

Re: Need Suggestions For Capturing Train Audio
 

I wonder whether the files that Scott sent are flat, or whether he applied some LF rolloff at some point.

I think a mic on a rail tie would have some problems. First, I'll bet the SPL is huge at that location, so you might need a special mic, some pads, etc., to avoid distortion. Also, there's the issue of perspective. If you got a *realistic* recording from a rail tie, you would hear the train approaching, coming within a few inches of the listener, then receding. You'd be unlikely to hear that in real life, unless *you* were located within a few inches of the passing train.

A boundary mic (or pair of them) located a reasonable distance from the tracks would be an interesting approach, and might be worth a listen. However, I don't think that would necessarily capture any more LF information than an omni (or pair) at the same location. Omnis tend to have pretty good LF response.

Maybe we need to think more about the issue of perspective. I recall reading an article that said you can never realistically capture and reproduce sounds (except for single-point sources). That's because you are recording only the sound waves that reach one (or two) points -- your microphone(s), and playing back all those sounds through only one (or two) speaker(s). The goal is to create an illusion that makes the listener think the recording sounds the same as the original sound.

So Scott, where are you, in relation to the train, when you make the recording? And do you want the recording to sound like what you hear at that distance, in that location? Or do you want it to sound like a train sounds from a different distance/perspective? Do you want to concentrate on the sound of the engine as it approaches, passes, and receeds? Or do you want a "realistic" sound of the entire train as it goes past... concentrating on the sound of the wheels on the rails and other hardware sounds after the engine has gone past? Do you pan the camera to follow the engine as it passes? If so, the engine will always be centered between channels, and one ear will end up facing toward the train, while the other ear ends up facing away from the train. If you pan the mic when you pan the camera, the perspective will change. On the other hand, a good recording of a passing train will have a fixed perspective, looking perpendicular to the closest point of the tracks.

Scott, please explain in detail what you want to hear, and what you dislike about your present track.

Darn, I might need to drive down to Altoona and see what I can record at the horseshoe curve... not today, though, when the weather is a little bit warmer. Before I do that, I'd like to hear from Scott about what distance and perspective he's trying to capture.

Re: Need Suggestions For Capturing Train Audio
 

Thanks Greg and Jim.
After reading your replies, I've realized some things: One, I know very little about this subject, two, I guess I am trying to buy my way out of this problem rather than learn, and three, I should have offered a link to a clip including video to let you see what moves and distances were involved in the recording.
So I will include a video link at the bottom of this post.
The closest distance I assume is around 150 feet. I know you will instantly think this is way too close, and I agree. I have had much better results when I could get more distance. But most times I simply cannot get further away, due to trees, private property, etc.
The sanyo model is the sanyo vpc-fh1a. I looked for audio specs but could only find 48K 16 bit.
Generally I am after the sound of the locomotives working hard. I am looking to get that sound at approaching distance, passing in front, and receding. However sometimes locomotives are placed in the center of the train, and I would like to capture them going past in front while the lead locomotives are in the frame. You can see an example of that in the link attached. I am not really looking for the "whole train" experience, but with a priority on the locomotives, and the railcars included only to show the size of the train. In fact many times I edit out most of the railcars.
I feel the panasonic/AT875r combo did not capture the "hiss" (for want of a better word) of the locomotive exhaust. I feel that is present in the sanyo clip. Again I'm far from knowledgeable, but it sounds to me like the AT875r has missed the higher frequencies. In particular, the sound coming from the locomotive at the rear of the train seems to be blown out by something.
I appreciate your answers and I hope this info is what you were looking for.

http://dl.dropbox.com/u/19575495/sou...0panasonic.mov
http://dl.dropbox.com/u/19575495/sou...ip%20sanyo.mov

These clips ar 80 megs or so. If thats too big just let me know what is appropriate.

Re: Need Suggestions For Capturing Train Audio
 

Hi Scott,

Nothing wrong with spending some money to solve the problem... if that will solve the problem. But first it's best to understand the problem and try to figure out a reasonable solution, to avoid throwing away your money [u/]without[/u]solving the problem. ;)

I don't think there's anything wrong with 150' distance. I have heard some train recordings that were supposedly made between 25' and 50' and they sounded quite different from yours. But those were not engines laboring up a grade, those were trains sailing by, probably not working very hard. They were moving a lot faster, there was a lot more noise of wheels on the rails, rail scrape, etc., but not the sound of engines laboring. But since those recordings sounded OK at that close distance, I think 150' is probably quite acceptable.

Right, there are no specs for your small recorder and its internal mics. It's possible that recorder actually rolls off the low frequencies, to minimize room rumble and wind noise. It's also possible that recorder boosts the highs (above 10kHz) to increase articulation of voice recordings. There's no way we can find this out accurately, unless we rent an anechoic chamber and test the machine.

Still, the specs say the 875R is pretty flat, so I don't think its highs are rolled off, unless it's somehow defective. (Is it new? Has it been dropped or abused?) Did you have the mic muffled in any way? Perhaps something to cut down on wind noise? How was it aimed? And is there any kind of "high cut" or "low pass" filter in the camera, that might have been turned on?

(Hoping someone familiar with that camera might chime in here.)

You will see the 875R's acceptance angle is fairly narrow. Note that a mic is not like a lens, in that there is not a specific area that is or is not "in the frame." A mic's pickup falls off gradually as you go off axis. But some mics (like yours) fall off faster than a standard cardioid pattern; and an omnidirectional mic does not fall off at all. But note this: a mic's high frequencies fall off more abruptly (as you go off axis) than the low frequencies. Therefore, the mic will sound flat only when pointed directly at the desired sound. So with your mic, unless you pan it to follow the engine, it will likely sound muddy except when the engine is directly on the mic's axis.

I would therefore suggest a cardioid pattern, or even an omni, as an experiment. Don't you know any audio folks in your town who would be interested in participating in an experiment? Borrow a nice mid-range cardioid, or start with an omni, and see how that works. That will give us some more data and a good frame of reference.

Meanwhile, I'll wait for the weather to warm up and maybe take a weekend jaunt to Altoona.

Re: Need Suggestions For Capturing Train Audio
 

Thanks for your info Greg. Unfortunately I am kinda rural, so no good stores around to buy from. And I know no-one else interested in this filed so no chance of borrowing any gear. I'll just have to take advantage of Amazon's generous return policy (and ultimately buy from them). With that in mind have you any suggestions? The Rode Stereo Video Mic comes to mind, but it would make my XLR adapter redundant.
Meanwhile I will experiment more. I DID have a windmuff on the mic, specifically a Wind-Tech mic-muff. I'll try without it next time. I have also discovered that if I switch the limiter in the camera on, then set the two recording levels in the XLR adapter differently, the limiter will cut off both channels even though only one is overloading, ruining the benefit of setting them differently to begin with. See here in the FCE audio graph:

http://dl.dropbox.com/u/19575495/Scr...04.22%20PM.png

It's just so difficult to gauge where I should set the recording levels beforehand, what with the different locomotive types and differences. Thanks again.
Scott

Re: Need Suggestions For Capturing Train Audio
 

Scott, a picture is forming as we continue the dialog.

Too bad you are rural as you describe. Actually, I am too, although I'm very close to Penn State, there are no reasonable audio dealers nearby, just a few music stores. Do you have any music stores near you that could lend or "sell on approval" a reasonable omnidirectional mic? How about a Radio Shack? I'd really like you to try a traditional cardioid mic, and/or an omni. It doesn't need to be the world's greatest mic, we just want to try a different directional pattern for comparison.

Here's some more theory for you. High frequencies fall off more rapidly with distance than low frequencies. They are even somewhat "blown away" because of high winds, or because of atmospheric refraction. Go and listen to a carillon on a windy day, and listen to how the sound of the bells changes constantly. We might theorize that your recording sounds a bit muddy because you're too far away. But then, on the other hand, the recording from your xacti sounded much brighter... that would tend to contradict that theory.

I apologize again that I'm not familiar with that camera. With some equipment you can "un-link" the AGC or limiter so the channels are independent... check your menus. Otherwise, I guess it's just a matter of trial, taking notes, and garnering experience. Eventually you will know where to set the levels.

Keep smiling. What you are doing is rather uncommon. If you had come in here and asked what mic to use for dialog on an indoor set (or some similar question) you would have gotten many answers from many people who have already done that. You are exploring rather new territory. It will eventually fall into place. Meanwhile, Google and see what you can find about train recording; someone, somewhere, has done it before.

If you are recording outside, you almost definitely need some sort of wind muff. If it's a legitimate known brand, it should have negligible effect on frequency response. And if you try again with your present mic, keep it pointed directly at the engine, because that mic is very directional.

As far as a good omni mic, perhaps someone will chime in with a suggestion or preference. I have read good things about (but have not personally tried) a Behringer ECM8000. It is a very small diaphragm omni condenser mic. It's designed as a measurement mic and is supposedly very flat. I've seen them online for as low as $50 so you could easily try one and if it's a winner you could get a pair and record in stereo. Not based on my personal experience, though...

Also, your brain does some amazing processing with the signals from your two ears. If you stand in a given location and listen with both ears, and then record with one mic, the resulting recording will not sound like what you heard in person. If you are going to record with one mic, then you need to listen with only one ear when you pick your recording location... plug your other ear with one finger (or wear a good isolation muff on one side). Location, location, location...

Too bad you aren't near central PA. I have Altoona's horseshoe curve here, I think there are trains climbing frequently, it should be a good place for some test recordings. As I said, when the weather gets warmer...

Keep us posted on your progress, and good luck!

Re: Need Suggestions For Capturing Train Audio
 

Hi Scott,

Being an avid Railfan I have come up with my own solution as to getting quality field audio at varying distances.

I've attached a link to the audio portion of Norfolk Southern's (NS) "Office Car Special"(OCS), and the actual Youtube video. The sound is approach from the right, pass, and departure to the left. I shoot with a JVC GY-HM700U with audio captured with a Rode NT4 stereo mic mounted on a shock mount inside a Rode Blimp on a K-Tek boom pole mounted on a Avenger C-Stand. The mic ends up around 15 feet high and perpendicular to the approaching trains. Mixer was a Sound Devices 302. Train is F9A/F7B/F7B/F9A + 11 Norfolk Southern Business/Office Cars. At the time, I set up about 150-175 feet from the track with the equipment.

Location is MP 22.1 on the NS Reading Line, in Longswamp Twsp., Pa. on September 26, 2010.

Audio: NS-951 OCS Train - Audio of NS-951 the Norfolk Southern (NS)"Office Car Special"(OCS) Sound is approach, pass, and departure sound. Captured with a Rode NT4 stereo mic mounted on a shock mount inside a Rode Blimp. Mixer was a Sound Devices 302. Train (Press on the player at the bottom to hear the train.)

Video: YouTube - Four Train Set..with NS "OCS" !!! - Sept 8th, 18th, & 26th 2010

Note: The video has good examples of trains in various distances using the same audio equipment. Skip to 7:08 for the OCS.

Here is a picture of the equipment setup along trackside. The other shows where I was in the large field giving a sense of the distance from the OCS train.

Steve

Re: Need Suggestions For Capturing Train Audio
 

I was thinking that an Omni/Figure 8 M/S setup might work out well. Tucson used to be a railroad town - maybe I'll find some good place to try it out.

Re: Need Suggestions For Capturing Train Audio
 

Steve, that is excellent detail. Thanks for adding some specific information.

I'm surprised you set up only 15' from the track, that's much closer than I would have tried it (but I am not disagreeing, you're the man who's done it!).

That will give a much different sound from Scott's recordings at 150' distance. That's why I asked Scott about what perspective he was trying to achieve.

I am curious about only one part of your description:

Do you mean you set up the mic 15 feet from the track, then ran mic lines back to a location 150 feet away? If so, why? Why not just set up the recorder near the base of the mic stand? Maybe I'm missing something obvious...

By the way, where is Longswamp Twp. in PA? I'm in State College, near Altoona.

Thanks again!

Re: Need Suggestions For Capturing Train Audio
 

Where I was going with the boundary mic idea was, when you are close to a train moving by the low frequencies make you feel the presence of the train. So I was thinking an audio track that captured the low frequencies would help reproduce that presence.

Re: Need Suggestions For Capturing Train Audio
 

I hope this reply is posted OK. The board seems a bit confused. When I click "Reply" at the bottom of the thread, it opens a reply box that includes quotes from a post half way up the page. Hmmm.

Jim,

I see your point about the boundary mics. It comes back to the question of perspective. That would definitely capture the "up close" perspective, especially if played back over a system with a beefy sub.

I see now there is a wide range of expectations. Steve records from 15' away. His sound reminds me of my teenage years when we'd hike through the woods to the nearby Pennsy ROW and wait for the trains to come up (or down) the river. It was fun standing that close watching (and hearing) them fly past.

Another perspective: I grew up in a hilltop community about a mile from the above mentioned ROW. Going to sleep every night, we'd hear the trains come whistling down the track, and the rather mournful sound of the whistle echoing off the hills on the opposite side of the river. (Couldn't hear the trains themselves from that distance.)

At another point I was in a town which was bisected by a B&O line, standing at the crossing gate less than ten feet from the rails, as the freights crawled through town on their way to the steel mills. (The hydraulic gate was pumped down by hand, by a watchman in the crossing tower 20' or so above the street.) That's when I heard the repeated ka-thump, ka-thump as the wheels slowly rolled past and deflected the tracks up and down. My memory isn't vivid enough to recall whether I actually felt it through my feet, but I probably did at that distance.

So yes, different perspectives and different trains flying, crawling, laboring, will give distinctly different sounds. I've ridden passenger trains up around the horseshoe curve, and I've watched them from the highway a mile away, but I've never stood near that part of the line to hear the engines making the climb. I've already checked Bing to see how to get there from here, and I will definitely make the trip once the weather warms up. Not to mention the historic steam excursion line about an hour from here...

Thanks for starting an interesting thread, Scott!

Re: Need Suggestions For Capturing Train Audio
 

Go for steam - so many more great sounds. When I was a kid steam was IT - they had the great looking sort of art deco GG1 electrics once you got to the electrified line into NYC but north of there it was steam all the way. Steam sounds so much more - well ALIVE, I guess. So many more emotions than diesel. Pants like a big dog.

Pennsylvania State Locomotives - Steam Locomotive - Electric Locomotive

The Japanese bullet trains don't even slow down as they whoosh through the stations where they don't stop - there's an announcement that they're coming and a request to step back from the edge of the platform - but boy do they ever make a great sucking sound as they whip through - never thought of recording them but now I have the bug in my head I might just do it next trip

Great thread indeed. Thanks

Re: Need Suggestions For Capturing Train Audio
 

Greg,

My distance from the track varies dependent on the location and available shooting space. The shot showing the equipment was in Duncannon, Pa. on the NS Pittsburgh Line along the Susquehanna River. I try to get 25 feet but some locations are tighter. 15 feet overall, is the closest I ever get to the side of the tracks.

In my comment, the 15 foot number is about how high the mic ends up above me. as you can see in the picture, it's slightly closer to the action then me. When this close I have to be watching the levels on the 302 right as the engines arrive. But when set correctly the first time, every train thereafter is usually fine. As long as I'm lighting the led's near the top threshold on the 302, and not hitting the limiters I'm fine. The entire audio package is always kept right next to me. I use 25 foot cables, and have longer, but I've never gotten in a situation where I needed them.

On the shot with the OCS train, the cam, mic, and audio equipment were set up at about 150-175 feet from the train. The only thing I did was keep the height of the mic lower and sloped out in front of me about 5-7 feet but high enough as to not be in my shot.

Longswamp Twsp, Pa. is on the Berks & Lehigh County line. not far from Kutztown, Pa.

Steve

Re: Need Suggestions For Capturing Train Audio
 

I would try the AT8022 stereo mic for about $359 online. It can be used either as balanced XLR or unbalanced mini-plug, as well as phantom or battery powered.

I'd also add this shockmount for $50:
http://www.bhphotovideo.com/c/product/554681-REG/Pearstone_DUSM_1_DUSM_1_Universal_Shockmount_for.html
And add suitable furry wind protection. Stereo mics using one large grill tend to be very sensitive to wind noise.

Re: Need Suggestions For Capturing Train Audio
 

Thanks everyone for some great advice here. Greg, I am ordering the Behringer ECM8000 today. I will take that along and try it as soon as it arrives. My nearest railroad is 30 miles away, and trains are a bit infrequent, which is why it's difficult for me to use one train to calibrate and then wait for more.
Steve, those are fabulous audio and video tracks. In your youtube video, I'm really impressed with your capture from 5:39 through 7:03. the train can be heard clearly from approach, yet no distortion from the horn even up close. That is what I'm looking for, along with the laboring sound of the locomotives on a stiff climb.
You guys have lit a fire under me now, and I am going to spend more time getting this right. Thanks !!
I will report back with any results. While I wait for the omni mic to arrive I will stop using the limiter and try and get some kind of feel for where my settings should be using my AT 875R.

Re: Need Suggestions For Capturing Train Audio
 

Jay:

It's interesting that you'd suggest the AT 8022. I have one of the two predecessor versions, the unbalanced AT822. I thought I'd try that as a minimalist approach to train recording. (Of course I'll have to check the headroom specs first, especially since it's powered by only 1.5 volts.) I will probably also take a pair of A/T small omnis, and maybe a pair of cardioids just for comparison.


Scott:

Let me know what you think of the ECM8000. I hope I haven't given you bad advice, but I have read some good things about that model, and it's certainly inexpensive enough. If you like the sound of one, do consider getting two; I really think stereo will help your "audio illusion."

• Does anyone else have any experience with the ECM8000? Please post your findings!

I, too, am about 30 miles from the main line (in Altoona) but I think the trains there are fairly frequent. I surely hope so because I'd like to try numerous takes when I go there for a day trip.

I am still pondering the correct "perspective" for trains. On the one hand, I like the real feeling of power from the engines, which seems to be captured best at close distances. On the other hand, close distances create a little too much stereo spread for my taste... the train approaches fast, is close and loud for a second or two, then zooms into the distance. I would like the "fullness" to last a little longer.

I realize some of these videos are made from perhaps 30' from the track, and the perspective I've heard is probably realistic for this distance. But I suspect it would be more pleasing to me if the train sounded close for a longer period of time. (Or do people get a "rush" from having the train zoom past so quickly?) Again, I think recording from the inside of a curve would help with this goal. (Sort of like the old visual trick of filming someone running through the woods, using a stationary camera on a pan head, having the actors run in a circle around the camera so the distance remains constant.) I will have to ponder this further.

Maybe this thread will pick up as the weather gets warmer. Keep us posted!

Re: Need Suggestions For Capturing Train Audio
 

Puttin' on my other hat as a volunteer machinist at the local railroad museum, let me suggest that locos are BIG---and they make different noises in different places. The 15 ft height suggested is great for detail on the diesel engine, which makes distinct noises from, for example, the valve assembly at about chest height if you're on the catwalk of the engine. And the horns, exhaust and such, are all pretty high up.

On the other hand, the sounds of the trucks on the rails, the air brakes, various squeaks and rattles, are pretty much assoicated with the lower parts...the electric motors which drive the wheels are set low. I can see, if shooting close-up, a two-tier mike system would be good.

Steam locos have lots of moving parts and different sounds from front to back as they pass, as well as from high to low on the loco and present a real challenge, I think.

The farther you get from the loco, the more detail is lost and the more the sounds become sort of a heavy rumble at low speeds. At high speeds, at a distance you can get the doppler-shift sound as the train comes nearer then goes away, but lose a lot of the rail sounds.

Re: Need Suggestions For Capturing Train Audio
 

Hi All,
I have had a couple of weeks to try out the Behringer ECM8000, and I have to say that for $50 it does an admirable job. Compared to the AT875R I was using, the Behringer has a slightly more muffled sound, and high frequencies are not as crisp as the AT. But at 1/6th the price the Behringer is an excellent alternative.
I found the Behringer to be less sensitive. Now I know the term "sensitivity" may mean something significant to you audio experts out there, but in my limited knowledge I mean it to be how sensitive the meter reads when sound appears. In this instance the AT is much more sensitive to changes in audio levels, and the audio meter dances up and down way more than the meter that's reading the Behringer. In some ways that would make the Behringer a better choice for me, but when I compare the two I can't let go of the crisp high frequencies out of the AT, especially when the train air compressors let a blast of air out. That's where the AT shines.
But I have to say that neither of these mics, or for that matter ANY mic, is going to solve my problem. Because with my Panasonic HMC40, I can only guess at the best setting for any mic, and hope it doesn't get overloaded. Trying to turn down the little wheels on the XLR adapter would not only jolt the camera, but probably overload my brain functions and ruin the shot. Kinda like rubbing your tummy and patting your head. So is there any way I can buy some kind of machine/attachment/device that does record high quality sound, but also automatically adjusts gain to get good audio at a distance but compensate automatically as the train nears and the sound rises? Field mixer with auto gain perhaps?
I understand that to the purists what I am looking for is not real true audio. But for my needs I want the sound of the locomotives to be dominant throughout the whole shot. From approach, to pass and to receding. Thanks for all your help.
Scott

Re: Need Suggestions For Capturing Train Audio
 

Hi Scott,

Glad to hear you're still "on track" with the project (pun intended).

Very interesting observations. You hear a "brighter" sound with the AT, and that corresponds to the difference in frequency response. Look at the two graphs attached, showing output level (vertical scale) versus frequency (horizontal scale). Notice that the vertical scale on the two graphs are not the same. The AT875 has a peak of around +4dB, from around 4kHz to 7kHz, while the ECM8000 has a peak of around +2dB and a much smoother peak at that. So yes, the AT probably sounds brighter. Also, the AT has less output at the very low end, which shifts the frequency balance higher... again sounding a bit crisper.

What you call "sensitivity" is not quite the usual definition. However, I understand what you're saying. I can only offer some guesses here. The AT is very directional so it is picking up different sounds as the train goes past; the Behringer is omni so the sound it picks up does not change as much when the train passes. Also, lower frequencies tend to be more constant in level (over a short time); higher frequencies bounce around more, and the AT is slightly more sensitive to high frequencies. All this could explain why you see the levels bouncing around more with the AT.

Certainly you can buy a separate audio recorder, with good metering, switchable AGC, and switchable peak limiting. You will need one that supplies at least +11v phantom power to the mic, so that will elminate some of the less expensive recorders. Zoom makes a few which seem to be well regarded, the H4n (which even has a nice stereo pair of mics built in) is around $300; there are others upward from there.

I would advise against using AGC, as it will try to make the level uniform. That will sound unrealistic, as the train is much quieter when it's 100 yards away than when it goes past 50 feet away. I have heard some bad train recordings where the whistle blows causing the AGC to lower the gain significantly. As a result, while the whistle is blowing the sound of he engine becomes extremely quiet; when the whistle stops you can hear the AGC quickly "turn up the level" of the engine. VERY unrealistic.

I would suggest you set your level when the train is at its loudest... the nearest distance and with the whistle blowing. Adjust gain so you are recording at around -6dB. Then don't touch the gain control after that. You could also turn on peak limiting (if available) and that will protect you from clipping if the sound increases unexpectedly. (Peak limiting is quite different from AGC.)

Perhaps some other folks will jump in here with recommendations for specific recorders.

Meanwhile, if you do get an H4n, please do try recording in stereo... just use the integral mics... and see if that doesn't sound much more realistic than a mono recording does.

Thanks for the update, and please keep us posted!

Re: Need Suggestions For Capturing Train Audio
 

Thanks Greg, and all others who have contributed to this.
I have looked at the Zoom H4n, which seems very nice. I also had a look at the Marantz 661, which is considerably more expensive. However I happened to see the AT 8022 that Jay recommended. Both the Zoom and the AT are comparably priced. So here I go with more questions.....
Should I buy the AT 8022 or the Zoom? I have no need for an external recorder other than accompanying my video camera, and it would add the additional task of importing and syncing external audio, but would it be a better choice than just adding an AT 8022 to my camera and XLR adapter? Would one be better sounding than the other? I can try either (or both) and return if I don't like, but any advice would be appreciated. Thanks again for following along with this!!! I have to go out this morning but later I will post some audio files from train video I took Saturday.

Re: Need Suggestions For Capturing Train Audio
 

Here are three attachments of the same event taken last weekend. I'd like to ask you guys what you feel about these clips, which ones sound better and any obvious flaws you might hear.
The Behringer ECM800 and the AT 875R were plugged into the xlr adapter on my video camera. The Sanyo Xacti was on its own tripod and contrary to the other two, did not pan to follow the train (I only have two arms). However I wanted to include it since I think I hear a definite benefit to stereo. None were normalized or altered in any way, just exported from the original clips in wav format.

Re: Need Suggestions For Capturing Train Audio
 

I wasn't there, and I haven't listened to trains for many years, so it's hard for me to say which one is most realistic. All three recordings surprise me in that there's a lot less of the exciting "close detail" sound than I would have expected. But again, this is based on my hearing trains fairly close up, and decades ago. So this is more of a comment on my personal train memory, rather than on the accuracy of your recording.

I notice the two single-mic recordings have a fair amount of level fluctuation... presumably caused by multiple engines going past, or by your panning the mics. The Sanyo recording has very constant level, so I would guess that recorder has a lot of internal AGC, which will tend to make the recording un-realistic.

The response of the two single mics is as expected, based on the published curves. The Sanyo has more midrange and HF information (from about 500Hz to 6kHz), compared to the two real mics. I would guess its response curve is tailored to improve speech intelligibility. But again, this deviation from flat response will make for a less realistic recording.

The Sanyo recording has very little stereo information... it is almost purely monaural. I don't really consider that to be a stereo recording. Either it was very far away from the train, or else the "stereo mics" are disappointing. I don't really have any info about your particular Sanyo, but many times internal "stereo mics" are omni capsules, and in that case they will not capture a decent stereo image if they're more than a few feet from the sound source.

Out of curiosity, how far were the mics from the track? I have read some interesting theories about stereo recording. One such theory states that coincident cardioids (X-Y pattern) capture a good stereo image when fairly close to the source, but as distance increases, increased spacing between the mics is necessary to get a good stereo image. (This is analagous to the way really powerful binoculars have increased distance between the optics, to produce a good stereo visual image at really far distances.) If you subscribe to this theory, then a single stereo mic may not be your best choice if you are recording 100' from the trains. (In any event, a pair of mics will give you more flexibility than one single-point stereo mic.)

If you're looking at a big investment, it might be worthwhile to rent a mic (or two or three) and try them, before making your final choice.

Re: Need Suggestions For Capturing Train Audio
 

I was a fair distance away, Greg, probably 250-300 feet. I wanted to stay away to reduce the amount of panning I had to do, plus to try and reduce the "quiet-deafening-quiet" aspect of close-up recording. I feel in a way that I might have been too far away.
I understand what you are saying about stereo miking. Can I pick your brain once more and ask; if I bought another AT 875R rather than a stereo mic, how I should set them up for stereo? Should they be on tripods a set distance apart, or is their a way to mount them on the camera? Should they be pointed out at an angle or just mounted straight ahead?
Sorry if this is just regular info I should be researching on my own. If that's the case please let me know. I really appreciate all the help.

Re: Need Suggestions For Capturing Train Audio
 

Hi Scott

One thought - get the mic's off the camera and closer to the "action". Best location for picture and best location for sound are almost never the same. Maybe more "quite/deafening/quiet would be better if the whole point of the exercise is the sound of the train. As long as you don't clip, you can bring the volume down to survivable levels in post.

Just a thought

Re: Need Suggestions For Capturing Train Audio
 

Scott, I agree with Jim. I'm not sure exactly what "experience" you are trying to capture and re-create, but 300 feet seems much too far to get clear sound. You can zoom in optically with a long focal length lens, but you can't do the same thing with a mic. High frequencies are attenuated more than low frequencies, by the atmosphere itself, and by surrounding foliage, etc. Something recorded at a distance of 300 feet will always sound relatively muddy, compared to something recorded at 25 or 50 feet.

(In fact, I played this for a friend without any explanation about what it is. My friend says, "It sounds like wind in a hollow tube." Even after being told it's a train, my friend says, "There's no sense of a train at all." That hadn'd occurred to me, since I know it's a train, but in reality the main thing you hear is the low frequency rumble of the engine, no sense of wheels, tracks, etc. That might, in fact, be what you really hear at 300 feet, but it doesn't especially jump out and say "train" on its own.)

If I were in your shoes, the first thing I'd do would be to find a good distance to capture the sound clearly and fairly realistically. Only after finding a good distance would I move on to stereo and experiment with mic position to get a good stereo image.

As far as the soft-loud-soft aspect of the audio, I wouldn't worry about it. Don't use AGC. Set the level of the recorder so that you don't clip with the loudest sounds (including when the whistle blows). Then, if you really think the level varies too much, you can subtly and gradually adjust level using some audio editing software.

Unless you think the trains sound realistic and have enough detail in these test recordings, try again at a closer distance. Maybe 100 feet for the next attempt. Or... do you like the present sound?

Re: Need Suggestions For Capturing Train Audio
 

Thanks Guys. I'll try and get some more video this week. The weather has gone back to miserable.

Re: Need Suggestions For Capturing Train Audio
 

There is a distinctive sound to a train going by, if you are close enough---say, waiting at a crossing for the train to pass. The locomotive has a distinct low rumble from the diesel...assuming it's a diesel...and then each car, as it passes, creates a variation in the wind as the coupled sections between cars pass. And there is a regular clacking as, assuming you have non-welded rail or a rail junction at a crossing, as the wheels of each car pass over the intersection. It is a very rythmic sound but you have to be close enough to catch it....and then a deminishing whirr as the end of the train fades into the distance. This assumes the train passing you at some speed, of course....

Re: Need Suggestions For Capturing Train Audio
 

Battle,

Did you listen to Scott's samples? If so, do you concur that a closer distance would probably sound more like what we're accustomed to when we think of the sound of a train?

(Of course, as I've suggested before, the perspective of the audio has to somewhat match the perspective of the video. If the video is a LS from a mile away, you don't want audio from 15 feet. But if the video is a telephoto shot from 300 feet, which looks like 50 feet, then audio from 300 feet will sound wrong, and audio from 50 feet might sound correct. )

Re: Need Suggestions For Capturing Train Audio
 

Hi Again guys,
Following up on my earlier efforts, I bought a small widget that provides a 1/4" tripod screw on one end and slips into a hotshoe on the other and mounted it on my camcorder. I then put the small cheap video camera with the auto audio gain on this and then filmed a couple of trains going by using both cameras. I did this to try and make both cameras be the same distance and follow the same pan when filming. I noticed that while the cheap camera recorded poor audio, it did a far more satisfying (for me anyway) job of recording the train both at distance and closer. Now I know most of you feel this is not "real", is sorta fake, and isn't accurate, but it's what I'm looking for. And as I've said before, Picasso couldn't even get the eyes right and people flock to see his work. And I really need to concentrate on my pan and zoom when a train shows, so I don't have the capacity to worry about sound levels. So I've settled on some kind of auto gain. And decided to change cameras. So I'd like to ask you folks this: Looking at these two camcorders, the Canon XA10 and the Canon XF100( ouch), they say different things about the audio properties. Here's what is on the specs for the XA10.

"The Automatic Attenuator feature prevents high volume distortion and optimizes audio quality in situations when sound levels quickly change. It automatically keeps the audio clean and even. Additionally, two XLR audio inputs with phantom power can be found on the detachable handle. Both the built-in microphone terminal and XLR terminals have the option for automatic or manual audio level control".

And here is the ad from the XF100.

"Audio is recorded in 16-bit PCM format at 48kHz for amazing quality and fidelity. And both the built-in microphone and XLR inputs have the option for automatic or full manual gain control. To prevent variations in the recorded audio level, the dial can also be locked."

I'd like to ask: Do you think both of these are the same, just worded differently, or do you think only the XF100 has what I am looking for? I really have no idea what an Automatic Attenuator is, except maybe a limiter with a college degree?
Thanks everyone for following me through this.

Re: Need Suggestions For Capturing Train Audio
 

from a technical perspective I would thing "Automatic Attenuator" is describing a "limiter" which only controls loud sound that goes past a certain threshold.

where as "automatic gain control" would also add raising volume for soft sounds which is the part of AGC (automatic gain control) that people are mainly talking about when they say its undesirable to use automatic settings, as this is when hiss is raised to undesirable levels.

this is my best trtanslation of the two descriptions, but since both descriptions are speaking a sort of different "language or verbiage" its impossible to know if they are indeed describing the feature accurately to be comparable.

Re: Need Suggestions For Capturing Train Audio
 

Thanks Gerry, and sorry for the belated reply.
After reading the manuals for both cameras I think you are correct. I feel the XA10 only offers a limiter, whereas the xf100 offers the limiter, plus the option to control the gain either manually or automatically. I'll pop this question over on the Canon groups and see if anyone who owns one of these can enlighten. Thanks again.
Scott