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Author Topic: tascam DR701d or DR70d  (Read 7979 times)

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Offline myotis

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Re: tascam DR701d or DR70d
« Reply #30 on: June 20, 2016, 02:09:30 AM »
The trashcash can lid seems to isolate or focus the sound.  Finding this more of a challenge than first expected. 

I tried various things before getting my dish, anything that had roughly the correct shape. Most seemed to work, but none came close to a properly designed dish, so I wonder if the gain needed with better focussed sound would be less than you are finding.

One of the advantages of the reflector is that its magnifying the sound, unlike a shotgun mic which is just isolating it. I wonder if this is why good but not great recorders are often used. e.g. Olympus Ls11

Cheers,

Graham



Offline aaronji

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Re: tascam DR701d or DR70d
« Reply #31 on: June 20, 2016, 06:01:19 AM »
If I was primarily looking for a recorder for wildlife and natural soundscapes, these would indeed be the places to go, but I think I have been given some valuable advice and plenty to to think about, from asking here.

So I appreciate everyone's efforts :-)

I think you misinterpret my post; as I stated, there is a lot to be learned here, but you should definitely consider how different the contexts are.

To put it in numbers, assume that a birdsong is hitting about 86 dBSPL at 65 centimeters.  I took these values from the first paper I found that published both numbers.  Note that this figure is the upper bound of the 95% confidence interval for the loudest bird measured; there is considerable variability between the birds (~ 12 dB), so this is actually the best-case scenario (for this species, at least, as there must also be quite some differences between species).  Anyway, taking that as a ballpark figure, at 20.8 meters you are at 56 dBSPL and at 166.4 meters that call is at 38 dBSPL (these distances are powers of 2 times the original 65 cm that come closest to your stated range). By contrast, 100 dBSPL, a not atypical taper SPL, is more than 128 times louder than the 20.8 m birdsong and more than 1024 times louder than the 166.4 m song.  At the 20.8 m distance, a microphone with a sensitivity of 10 mV/Pa (kind of a typical taper mic value) will generate an output voltage of ~ -76 dBu, while a more sensitive mic, say 20 mV/PA (similar to the Rode) will output ~ -70 dBu.  These voltages drop to -94 and -88 dBu at the greater distance. 

The long and short of all those numbers, assuming I did the math correctly (a major assumption), is that you’re needs are dramatically different from the typical taper.  As I see it, you probably need high-sensitivity, low-noise mics with either a quiet, high-gain pre and a decent recorder or a quiet, high-quality all-in-one recorder.

Missing from all this is the reflector.  I don’t know anything about these, but, intuitively, there are several factors to consider there.  First, it should provide a substantial boost in gain, but this will be strongly dependent on frequency.  So if you are primarily interested in the notes the bird is hitting, and not the dynamics, then it should work well.  The dynamics will be off, though.  Second, it should lead to strong increases in directivity, again closely correlated with frequency.  To capture the highest frequencies, I would guess this requires very careful aiming of the dish.  Last, there should be some focal point where the diaphragm of the mic should be placed.  I would guess the tolerance is pretty tight with that, too, which probably played a role in 2manyrocks’ results.

Anyway, I don’t know anything about nature recording, so take all of this with the appropriate dosage of salt!  Which was really my point...

Offline myotis

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Re: tascam DR701d or DR70d
« Reply #32 on: June 20, 2016, 08:04:17 AM »
If I was primarily looking for a recorder for wildlife and natural soundscapes, these would indeed be the places to go, but I think I have been given some valuable advice and plenty to to think about, from asking here.

So I appreciate everyone's efforts :-)

I think you misinterpret my post; as I stated, there is a lot to be learned here, but you should definitely consider how different the contexts are.

Missing from all this is the reflector.  I don’t know anything about these, but, intuitively, there are several factors to consider there.  First, it should provide a substantial boost in gain, but this will be strongly dependent on frequency.  So if you are primarily interested in the notes the bird is hitting, and not the dynamics, then it should work well.  The dynamics will be off, though.  Second, it should lead to strong increases in directivity, again closely correlated with frequency.  To capture the highest frequencies, I would guess this requires very careful aiming of the dish.  Last, there should be some focal point where the diaphragm of the mic should be placed.

Anyway, I don’t know anything about nature recording, so take all of this with the appropriate dosage of salt!  Which was really my point...

Sorry, I'm not sure whether, I did or did not, misinterpret your post or just phrased my reply badly :-)

I will take you word on the sums. !

The parabolic reflectors are designed for the mic to be placed level with the outer edge of the dish, if that makes sense. 

There is an issue with frequency as they only strongly pick up higher frequencies, and some low frequencies are missed entirely. So good for song birds, not so good for birds with low frequency calls, unless you have an enormous dish !   A bittern is 101dB at 1m with a frequency of 155 hertz, which is apparently the volume of a trumpet, with the frequency of a tuba ! (from Trevor Cox "Sonic Wonderland: A Scientific Odyssey of Sound")

There are also issues with recording reflected sound and direct sound, and whether omnidirectional or cardoid mics should be used.

Not everyone is a fan, and there is a bit of an ongoing debate between the use of dishes vs shotgun mics.

I have just so much to learn !

Cheers,

Graham


Offline aaronji

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Re: tascam DR701d or DR70d
« Reply #33 on: June 20, 2016, 09:07:40 AM »
The parabolic reflectors are designed for the mic to be placed level with the outer edge of the dish, if that makes sense. 

Yes, that makes perfect sense.  I would imagine that a garbage can lid or other make-shift dish wouldn't work very well unless it was actually parabolic (or very close) and the mics were positioned as you describe.

There is an issue with frequency as they only strongly pick up higher frequencies, and some low frequencies are missed entirely. So good for song birds, not so good for birds with low frequency calls, unless you have an enormous dish !   A bittern is 101dB at 1m with a frequency of 155 hertz, which is apparently the volume of a trumpet, with the frequency of a tuba ! (from Trevor Cox "Sonic Wonderland: A Scientific Odyssey of Sound")

That's astonishing; they aren't even very large, are they?  I would imagine that is pretty exceptional, though.  They would be difficult to record, too, due to the low frequency.  Neither the parabola nor directional mics would be ideal for that.

There are also issues with recording reflected sound and direct sound, and whether omnidirectional or cardoid mics should be used.

Not everyone is a fan, and there is a bit of an ongoing debate between the use of dishes vs shotgun mics.

This all makes sense to me, too.  I guess there are always trade-offs to be made.  Shotguns tend to have some pretty funky looking polar patterns, but the dish also introduces some oddities.  Does anyone use hyper- or supercards as an alternative?  Maybe a little closer?

Offline myotis

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Re: tascam DR701d or DR70d
« Reply #34 on: June 20, 2016, 11:01:22 AM »

This all makes sense to me, too.  I guess there are always trade-offs to be made.  Shotguns tend to have some pretty funky looking polar patterns, but the dish also introduces some oddities.  Does anyone use hyper- or supercards as an alternative?  Maybe a little closer?

Yes, its a very popular approach

http://www.wildlife-sound.org/blog/2016/05/leaving-the-grouse-unattended/

for a sony M10, low cost omni-directional mics and pre-amp left on site running

And for a very  interesting blog  http://www.thesoundspace.co.uk/

is well worth a browse

Here there are some examples of running 70m of cabling from mic to recorder. But many others do this sort of thing, with much longer cables !

He won the WSRS silver fox award last year, but struggling to get a link that works

 http://www.wildlife-sound.org/agm/index.html

The recording is called Spring In The Lammermuirs.

There is a page of the kit he uses, so it might be interesting to see how it compares with what the average Taper uses.

The eurasian bittern weighs between 0.8 and 2kg, so pretty big compared to your average song bird which is going to under 100g.

Link to British Library Bittern booming http://sounds.bl.uk/environment/british-wildlife-recordings/022m-wbotaxstel01-0100v0

Cheers,

Graham


Offline F.O.Bean

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Re: tascam DR701d or DR70d
« Reply #35 on: June 21, 2016, 03:35:40 AM »
Yeah, you would probably be best suited with some small, great sound omnis like the 4060s/4061s, to really capture the ambiance of the birds in the trees and all around you IMO! But I have NO experience nature recording, so take that with a grain of salt! I just think that birds/nature would be best re-created with omnis!

And as far as needing an external preamp, if my low-noise Schoeps have that much noise at high gain levels, then most mics are going to be even noisier than that, so I would bet the FARM that you would be best suited with an external preamp and a separate recorder or more expensive all-in-one! If size is of concern to you, then you might want to run 4060/4061>DPA MMP Preamp[if funds allow]>Sony M10 or any handheld deck out there with a line input! The 70d preamps are probably too noisy to be run alone! However, if size isn't a huge concern, id still get a Tascam 70d[with an approved SD card], and then upgrade to an external preamp AFTER you try it out! Plus the 70d is TINY too IMO! Its only 6.5" long x 4' wide and fits EASILY into most recording bags! And you'd have the extra 2 channels if ever needed! Not to mention a 70d is around the price of a Sony M10 anyway :)
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Offline myotis

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Re: tascam DR701d or DR70d
« Reply #36 on: June 21, 2016, 04:04:47 AM »
Yeah, you would probably be best suited with some small, great sound omnis like the 4060s/4061s, to really capture the ambiance of the birds in the trees and all around you IMO! But I have NO experience nature recording, so take that with a grain of salt! I just think that birds/nature would be best re-created with omnis!

For soundscapes the omnis are popular but so are midside and double midside arrangements (but I'm not sure exactly what they are), but I still need a shotgun/parabolic for more distant things.

However, what has come from this discussion which I had't thought about was a separate PreAmp, and I agree that the way to go is to.  And as you suggest get the Tascam, so I have something general purpose to work with my camera gear, and xlr connectors and then look at an external preamp/mixer.  But  still not sure about whether the 701 is worth the extra.

Thanks for your help,

Cheers,
Graham


Offline aaronji

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Re: tascam DR701d or DR70d
« Reply #37 on: June 21, 2016, 05:45:27 AM »
And for a very  interesting blog  http://www.thesoundspace.co.uk/
<snip>
There is a page of the kit he uses, so it might be interesting to see how it compares with what the average Taper uses.

I have seen this site before; I think someone posted it here a couple of years ago (nature recorders pop up here on occasion, like yourself).  Pretty interesting.  It looks like he uses three primary setups, mid-side with Sennheisers, Senn. shotgun with a parabola, and 4060s remote with wireless transmitters.  Those Sennheiser mics have pretty high sensitivity (25 mV/Pa) and low noise and he is running them into high-quality Sound Devices mixers, which does seem to be the way to go, in general.  The 4060s (and I would get those and not the 4061s) are pretty low noise, although higher than an SDC, and probably work great at close range.  I think they do need to be quite close, though.

The eurasian bittern weighs between 0.8 and 2kg, so pretty big compared to your average song bird which is going to under 100g.

I was thinking about regular terns, which are a lot smaller.  The bittern is a pretty interesting bird; my five-year old was loving the calls (there are some videos out there too).  Learn something new every day and all...

Offline myotis

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Re: tascam DR701d or DR70d
« Reply #38 on: June 21, 2016, 07:54:16 AM »
I was thinking about regular terns, which are a lot smaller.  The bittern is a pretty interesting bird; my five-year old was loving the calls (there are some videos out there too).  Learn something new every day and all...

Ah, I see the confusion, as they aren't terns, but herons. But, fascinating birds as you say. There is a healthy population close to where I live and it can be spectacular hearing the males try to "outboom" each other. It's on my list of things I would like to record.

And yes, I suspect a SD mixer approach is indeed the long term aim.

Cheers,

Graham


Offline F.O.Bean

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Re: tascam DR701d or DR70d
« Reply #39 on: June 21, 2016, 11:38:29 AM »
Yeah, you would probably be best suited with some small, great sound omnis like the 4060s/4061s, to really capture the ambiance of the birds in the trees and all around you IMO! But I have NO experience nature recording, so take that with a grain of salt! I just think that birds/nature would be best re-created with omnis!

For soundscapes the omnis are popular but so are midside and double midside arrangements (but I'm not sure exactly what they are), but I still need a shotgun/parabolic for more distant things.

However, what has come from this discussion which I had't thought about was a separate PreAmp, and I agree that the way to go is to.  And as you suggest get the Tascam, so I have something general purpose to work with my camera gear, and xlr connectors and then look at an external preamp/mixer.  But  still not sure about whether the 701 is worth the extra.

Thanks for your help,

Cheers,
Graham



If you use a camera or ever plan on using one, and want everything sycned, then the 701 is probably worth it to you! If I had a camera Id DEF have a 701D! However, I got a 70d early 2015 for dirt cheap new, and then got a used 2nd 70d right before the 701 came out! Id RATHER have [2] 701D's, just for cascading and monitoring/metering alone, but it just doesn't make sense for me at the moment, to dump both of my 70D's and get [2] 701D's instead, especially since I have next to nothing invested in both of my 70D's ;) Hell, I got my 70d's so cheap that I'll probably just keep them until they break or quit working! But who knows how long that'll be? LOL!

If I were starting fresh, and only needed a SINGLE recorder, Id DEF throw down the extra $$ for a 701d vs. a 70d, especially if I were using a camera like you are 8) ;D As always, YMMV!
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Offline 2manyrocks

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Re: tascam DR701d or DR70d
« Reply #40 on: June 21, 2016, 12:07:01 PM »
My hazy recollection is the Panasonic gh4 and maybe one other dslr output time code over HDMI.  I would hesitate to pay $600 for the 701 without some very specific proof that it is a definite step up from the $200 70d and unless I  owned a camera that outputs time code over HDMI.   

 At $600, you're halfway to a used 702 with known established performance.

If the audio output to the camera is menu driven on the 701 like the 70d instead of a manual gain pot like on the 60d, not sure I'd like that. 

I am interested to hear more discussion of the parabolic dish setup.    Why aren't they used for festival recording?  I could immediately tell the dish tends to block noise from the rear. Looks like that would be useful to reduce crowd noise, and if we could use cardoid mics with a dish, then that would be less costly than mk41capsules. 




Offline myotis

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Re: tascam DR701d or DR70d
« Reply #41 on: June 21, 2016, 02:42:34 PM »
If you use a camera or ever plan on using one, and want everything sycned, then the 701 is probably worth it to you!

I'm certainly a little reluctant to buy the 70 when the 701 is available, given my primary purpose for it is to work with a DSLR, and it does offer some added camera benefits, better noise, better mixing and a more robust construction. As a long term investment which I could add a PreAmp to later, it seems a better choice, but it is still more than twice the price.

I am still thinking about it, but where as I was going to rush into buying something before going on holiday, I now think I will wait a bit.

Cheers,

Graham

Offline myotis

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Re: tascam DR701d or DR70d
« Reply #42 on: June 21, 2016, 02:53:07 PM »
I am interested to hear more discussion of the parabolic dish setup.    Why aren't they used for festival recording?  I could immediately tell the dish tends to block noise from the rear. Looks like that would be useful to reduce crowd noise, and if we could use cardoid mics with a dish, then that would be less costly than mk41capsules.


    Canon 5D Mark III
    Panasonic GH4
    Sony A7s
    Sony A7 II

are HDMI timecode supported cameras with the 701.  Nikon d810, no timecodes, but will start and stop the recorder from the camera.

But I imagine this will change as new cameras are introduced and Tascam firmware is updated

Omnis or cardoids  are both used in parabolic reflectors but I think the problem for festivals  is that they only pick up a limited sound spectrum (high frequencies only) which is fine for songbirds, but less so for general use. 

They also, at least mine does (moulded fibreglass) , pick up far more from the rear than you might expect.

Cheers,

Graham

Offline voltronic

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Re: tascam DR701d or DR70d
« Reply #43 on: June 21, 2016, 03:04:07 PM »
Just posted this - you may be interested.

http://taperssection.com/index.php?topic=178128.0
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Offline myotis

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Re: tascam DR701d or DR70d
« Reply #44 on: June 21, 2016, 03:21:51 PM »
Just posted this - you may be interested.

http://taperssection.com/index.php?topic=178128.0

Thanks, not sure if I am ready to make the leap yet, but it seems its delivery to US only.

But I am grateful for you pointing it out.

Cheers,

Graham

 

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