Long time recording

[7inch]

I'm looking for a device to record audios over a long period of min. 2 weeks.
I have read here much about the Olympus Recorders, but how is the quality in longplay mode ?
The problem with the power supply I would solve with additional battery packs.

Thank you for hints.

[jinhui]

i once used my olympus recorder for long term recording, with preset recording times and connected to a socket.
The sound quality is very good and can be set up according to the record situation. If you are outside a door or something, you can use the zoom function and a high microphone sensivity. If you are recording inside a room, maybe near the sound source, you can adjust it settings accordingly (low microphone sensivity etc.).

I like my Olympus DM550
best regards,
jinhui

[7inch]

Thank you for the information. Is the DM650 a newer version ? It costs 116 € and I think thats ok.
But can you tell me, how long you can make recordings with the Olympus DM550 ? Is it only depending on the memory size ?

[Audio]

It depends on the recording quality as well. you can download the manuals of the recorders you are interested and look through them for additional information on the possible duration.

[7inch]

Meanwhile I have bought two cheap USB-Recorders and one Olympus Voice Recorder. Here is my review of the devices:

The USB-Recorders have a built-in 4GB memory. That's enough for a whole night and even longer. However, I do not know yet how long the batteries will supply.
The sensitivity is sensationally good. However, the noise is a little bit loud, but still okay. At a price of only 10 €, it is possible, to place the devices unguarded
somewhere. On the first evening I've placed the two sticks in an area with many young people and was not disappointed.

You can hear the result here:
viewtopic.php?f=6&t=4483


The Olympus voice recorder DM650 costs € 116, but I think it is worth its price. It is processed in a metal housing and very good finished. The recording quality is also very good. the
three built-in microphones are very sensitive and the noise is very low. I always thought my phone would have a good recording quality, but in comparison with the Olympus
it's rather badly.
Depending on the recording format and sampling rate the 4 GB built-in memory reaches for up to 1026 hours (WMA mono, 8 kHz sampling rate, thereby very poor quality).
WMA 32 kbps with an acceptable quality are sufficient for 262 hours. With an additional 16 GB Micro SD card it can record 1046 hours.
The two batteries (LR03, AAA, Micro) supply power for 38 hours.
Unfortunately there is no way for an external power supply. So I have to build an adapter that connects the device with two large LR20 batteries. I still need to test
how long the energy keeps with it.

For comparison, I put three audio samples here. All devices have the same distance to the TV (3.50 m):

USB Voice Recorder:

REC003.mp3

Phone Sony with Smart Voicerecorder App

rec_20140919-2003.mp3

Olympus DM-650

DM650008.mp3

[Audio]

it is clear that the Olympus Recorder has the best quality out of this three.

[sc0tt-uk]

Yup, but to be fair, that's one of the better cheap recorders I've heard. Could you post a link to the model?

[7inch]

@scott-uk

here's the link to Amazon Germany:
http://www.amazon.de/dp/B009LWOH1Q/ref= ... 61_TE_item

It looks like this, but no guaranty , if it is the same:
http://www.amazon.com/Voice-Recorder-Fu ... e+recorder

[yeppie]

I have two of these and they work great.

[LeStanf]

I have a couple of these:

http://www.amazon.com/Etekcity-UR-8GB-R ... e+recorder

Some of my best recordings have been done on them. The battery lasts at least 16 hours and the quality's pretty good.

[reggind]

If you are handy with simple electronics you should be able to carefully dissect one of the USB stick recorders. I just bought 3 8 GB units from Amazon for right around $10 each, delivered. I am waiting on delivery now. I assume they are coming from China as the ETA on them is a month away. I am in no rush as there will be nothing to record all winter long anyway.

Anyway, two of the things I want to try doing with one of them is depending on it's battery voltage, cloning it onto one or more of the new 2700 mah AA cells. That ought to give it enough power to run for damn near as long as the memory holds out I would guess. I am figuring if the units are the same size as a regular USB stick, some of the space has to be taken up by the guts. The other thing I would like to try to do is clone a high quality microphone element onto it, such as a Primo EM172 (about $10 delivered). Note that the Primo EM172 mic requires near 9V on it to achieve it's full rated sensitivity, so this may require also cloning on a 9V battery or a small capacitor charged to 9V. The microphone requires an incredibly small amount of power so I am guessing a low loss electrolytic cap ought to run it for as long as the main battery will hold out.

The only thing that is frightening about this set up is with the beyond the pale sense of paranoia at public outings these days anything with batteries and wires hanging off of it better not be discovered or they may wind up evacuating the place and calling in the bomb squad. This would not be a good thing for a discrete recording. So, such a modified gizmo would be best really well camouflaged (diaper bag, perhaps even loaded, fake dog shit, hollowed out piece of a tree limb etc) or kept with you. It is a sad reflection on the world when you have to worry about shit like that but these days you need to.

[mjj9994]

Lol @ reggind and the bomb squad. In the US we have radio shacks where you can just get a cheap plastic enclosure for it.. maybe something like that would help to keep you from getting on the 'watch list' haha.

[reggind]

Good point! But a plastic electronics project box jammed next to someones tent is not exactly discrete. I think a hunk of a log that has been doctored would be pretty discrete for an outdoor thing as long as they don't allow fires (smile). I am pondering something around 4" in diameter and 6" long. Carefully cut in half with a band saw so you have 2x 4" round by 3" long pieces. Drill like a 1"hole in the center with a spade bit about 2.5" s deep on both sides and you have a pocket to put the electronics in. Drill a little hole to the outside to jam the mic in. I doubt most folks would look carefully enough to see a little 6mm black spot in the log. Drill a few 1/4" holes around the outside on each end to hold pins and hammer it together with pins. Ideally when you are done you have a pretty natural looking piece of wood that would not look too out of place in a field full of tents. That is for long term recording as in over days.

For short term I still think making the USB recorder look as much as a USB stick as possible and hooking it on to a ring with some old keys would work great. Give you an excuse to go and "look" for it without raising too many eyebrows. I was a bit drunk and I tripped over a tent line in here someplace and when I got back to my car, son of a woman my keys were missing. I must have dropped them when I fell. Oh, the falling also gives you the perfect opportunity to plant them as well.

Sneaky.