LaFolia

40 Hz removes sounds with frequency lower than 40 Hz. 120 Hz removes sounds with frequency lower than 120 Hz. 40 Hz is lower than 120 Hz, so the 120 Hz filter will remove more of the sound. The trick is to remove the sound you don't want and leave the sound you do want. For voice recording, 120 Hz is probably what you want much of the time, but you might find that it changes male voices. There are two things you really want to filter. First, if you have wind noise and don't have a wind screen, that can peg the signal, and you have to filter that. Second, if there are bumps and clunks picked up from floor, table, handling, etc., you probably need to filter that noise before recording. I don't think you will be able to remove the noise of a whoosh of air from an air conditioner. It's too high to filter (the frequency range overlaps what you are recording). But if the air is hitting a microphone with no windscreen, that will produce a low rumble that you need to filter. Filtering with Audacity after recording may help somewhat.

Correct. Special effects are missing, and some others. The Tascam Web site seems to describe it pretty well.

Oops, you're right, I did misunderstand what you meant about the effects. So that's solved. I know you know how to do this, but it's easy to miss a little thing like that, and who can remember everything that was written on 19 pages? If there is a problem with the microphone leads, I don't know why they couldn't just have used a thicker lead, rather than disabling a useful feature. I'm thinking of an example. The AR turntable used a thin, shielded lead from the cartridge. That was thin enough not to disturb the tone arm, but thick enough that they could leave it exposed on the top of the turntable. It lasted more or less forever, and did not pick up noise. In the recorder they could even use a thicker lead. It just doesn't make sense to me that the microphones don't swivel. Good call on the batteries, though. I assume that was your doing? If you record with a power supply, you're tethered to a cord, but with AA batteries you're not tethered, and you can be charging one set while you're recording. Plus, the power supply and cord are a lot bigger than an AA recharger. And power supplies are not completely quiet. They all add at least a little bit of noise.

As I wrote previously, I can jump up and down and shake it too, but I cannot duplicate your results. In your sound sample there was wind noise plus some "static". I don't get the static at all, and I don't get the wind noise either if I shield it. Perhaps you got a bad unit. I have to say, I think it's unfortunate that the microphones do not rotate on the DR-07. It makes it difficult to record yourself, as you can no longer see the record level. Everything involves tradeoffs, but the connection seems to be good enough on my DR-1. ??? I didn't hear any problem. Make sure special effects are turned off on playback. It's easy to turn reverb on by accident. This is one feature I wouldn't miss. Er, the DR-1 has an analog limiter, and I thought you liked it. I can add to this that I recorded a singing group and let them hear the result. The reactions were spontaneous and enthusiastic. One person just had to have one and will be buying it. It's a nice recorder.

??? The specs. are virtually identical. It looks the same except with some features removed and a tripod socket added. Are there other changes?

Update the firmware to version 2. You will find that on the Tascam Web site, under DR-1/Resources. I just had the same problem, and it fixed it right up. Takes a minute or two.

Well, I bought the DR-1, and I am very pleased. It's better than some of the reviews indicate. I didn't find some of the defects that Guitarfxr thought he detected. First, the noise when shaking the unit appears to be nothing but wind noise. Some sound samples were posted earlier that were said to represent a bad contact or a bad ground. It was easy to reproduce the noise, just like they said, but the problem disappeared completely when I wrapped the microphones with a pair of socks. (I didn't have a wind screen, so I had to make do.) Second, the internal microphones are well matched. I tested and found that they are matched within 0.8 dB. Here are the details. I generated white noise with Audacity and played it through a single, high-quality speaker. I pointed the DR-1 directly at the speaker, recorded 16-bit .WAV files and plotted the spectra for left and right microphones with Audacity. To eliminate problems with diffraction and room resonances, as described in the next paragraph, I moved the DR-1 continuously while recording, and recorded at three different distances. I copied the spectra to a spreadsheet and plotted the difference between right and left in dB against frequency. The average difference was 0.8 dB. The RMS difference (i.e., standard deviation) was 1.5 dB. I initially saw some big differences between left and right at certain frequencies, but I found that the results depended strongly on the position of the microphones. By putting my ear where the recorder had been and moving it around a few inches, I could hear differences. To avoid this problem and to average out the irregularities I moved the microphones continuously during recording. I also tested the frequency response against a known microphone, but I don't think the results were reliable because that was before I fully appreciated the effects of position and directional characteristics. Keep in mind that this is a live living room, not an anechoic chamber. The main disadvantage from my point of view is that there is virtually no stereo separation. I walked around the recorder with a sound source, but could scarcely hear a difference between right and left until at least 90 degrees off axis. Again I plotted the spectrum with Audacity, but I could hardly detect any difference between between right and left at up to 60 degrees off axis. Looking at the bright side, it's very nicely designed and well built. The buttons and controls are handy and work well. It's nice that you don't have to remember to save a file when you record, so you don't lose recordings. The menus are fairly simple and well designed. You will probably need the manual for some things, but there is nothing difficult or complicated. It's very handy for a musician, and I can recommend it. I recorded a concert inconspicuously with it laying flat in my lap. The crowd was quiet; neither crowd noise nor handling noise was a problem. The sound was actually quite good. Overdubbing is a little tricky, but I found the most difficult thing to be the short cords on headphones.

Wow! A real fanatic! Also, when comparing microphones, note that many have greatly enhanced treble for speech recognition. If you are trying to reproduce sound, a perfect microphone would sound lacking in treble by comparison.

Thanks for doing this, but I liked it a lot better before you deleted all that information. The value of this is not in just some single curve, but in the comparison with a known microphone. If you just post one curve, you are measuring a combination of (1) speakers, (2) sound system, (3) the room, and (4) the microphone. If you compare it with a known microphone, then you can eliminate all but the microphone. In this case the specs. of the other microphone are sort-of available, but the frequency response depends on the capsule type. Did you use the omni, the cardioid, or another? As other people noted, even that is not absolute, because the response is different on axis than off axis. What we are after is mainly the on-axis (45 degrees) spectrum, I suppose, but the spectrum with it pointed straight ahead is also interesting because that's how it's going to get used much of the time. So it's probably a shame that you deleted all those charts. Also, different microphone types will pick up different spectra in a room. You might get more bass and less treble from the walls, for example, so an omni may sound different from a cardioid. So there is going to be some slop in the tests, but it's probably a lot better than nothing, which is what the manufacturer gave us. Personally, if I were doing this, I think I would use white noise (which Audacity can create) -- because by definition it is completely flat across the spectrum.

It starts rolling off a little under 13K. There's a broad rolloff in the bass too. This was not easy to find. Is there any such information for the Tascam?

Is there anything like this for the Tascam? H2 microphone specs

I was wondering mainly about the Tascam, not the mike. I meant, can the Tascam work with the AT822 or similar condenser mike at distances around 5-10 feet, without excessive noise?

Urk. Duplicate post deleted. Cranky editor.

OK, there's not a lot of objective information out there, but I did find a little. 1. O'Reilly H2 review With a little refinement, a a test like this should be done with all recording devices. I thought at first this was really convincing. Mark Nelson walked around an H2 while strumming a ukelele, and you can clearly hear it move all around the recorder. That's as wide a stereo source as we can get. If the test could be repeated over a narrower angle, say 120 degrees, that would tell us what we need to know. I could be wrong, but could it be that the ukelele doesn't seem to move much until he gets way out to the side? One thing is sure, though: the tone quality is rather uniform at various angles, and that's important. I must say it sounds good. 2. Ozpeter's H2 review You can clearly hear the the helicopter and train pass by. Was that recorded with the internal microphones? (Alas, because the train is not a point source, I'm still not sure how much stereo separation there is in the middle of the stage.) 3. There's one review on the DR-1 that includes some distinctly stereo sound. Paul's review At 32 minutes, 45 seconds you can hear a truck move from left to right. Convincing. Unfortunately, at 24 minutes, you can hear the tone change a little as he moves it from side to side. It changes a lot if he rotates the microphones up 90 degrees away from the mouth, but that's not a fair test because both both microphones are rotating off axis, whereas normally if a source moves toward the axis on one mike it moves away on the other. Summary So I think the DR-1 does a decent stereo image, although a truck driving by may not be as good a test as Guitarfxr's ear. I'm less sure about the H2. Finally, note that I'm interpreting someone else's recordings. Someone else may want to try this with actual recorders in hand! Remember, no fair using limiters or AGC.

Thanks for the replies. Some things are getting clear, but there are still some questions. Do you have a sense for the microphone pattern? Cardioid? Omni? 120 degrees or 90? "EDIT: You have mentioned that the noise level changes with ambient noise. You wrote, "in a quiet room the noise filter algorithim just doesnt know what to look for so the unit gets noisy". ??? Is this with the limiter or AGC? What noise filter algorithm? EDIT: You sort of answered this question: I'm also confused about the conclusions so far. I read the first 10 pages or so carefully, then found out that much may be based on a defective unit ??? Ran out of time. Is the verdict still that M1 and internal are noisy, but M2 and line are not? Trying to get a feel for how this would work in practice. I accept that external microphone(s) is probably needed for stereo (but still evaluating H2). Separate microphone pair can be used sometimes, but often not an option, so will need stereo mike. Multiple mikes and mixer definitely not an option. Would AT822 or cheaper AT likely work for distances around 5 feet, with reasonably low noise? Our music is not particularly quiet or particularly loud. (Still, I know with a dynamic mike I don't like to record at too great a distance with other recorders either.) Hopefully an AT822 or cheaper AT25, etc. would work better than EV RE-15 dynamic? Ozpeter and others: Still evaluating H2. Interesting sound samples, not bad sound at all from internal mikes. I'm analyzing waveforms as time permits. Stay tuned.

I notice that there is very little information on stereo imaging. I'm not an audio perfectionist, really, but I need to record instruments -- mostly violins -- and I need to be able to do stereo separation. In other words, some instruments are too quiet, some too loud. I also need to do this rather casually, i.e. without setting up much equipment. I'd prefer even to use the built-in microphones. Preferably under $400 total. A few candidates: DR-1 Edirol R-09HR (great recorder but virtually no stereo separation in built-in mikes -- just two omnis separated by a couple of inches) H-2 ("sub-cardioids" -- almost omnis -- probably little separation unless you turn it around and record from the back of the microphone?) Olympus LS-10 (probably pretty good -- unfortunate bass rolloff if I ever need bass) Sony PCM-D50 (probably done right, but expensive) Any comments? Info on DR-1 or stereo sound samples? (There are a few links that might show separation, but links are broken.) Thanks.