Boya BY-V01 stereo on camera microphone

Today, I’m looking at the microphone is the BOYA BY-V01 Stereo X/Y Mini Condenser Microphone.

This cheap stereo microphone is available on eBay and other locations, for about $30 Australian. I bought it wanting something cheap and low profile to sit on my camera most of the time, so I can get better sounding audio when I’m shooting, and I don’t want the bulk and clutter of the Rode Videomic.

From the outside, it looks OK. It’s a nice size, doesn’t stick out too far, and seems reasonably built.

The mic in place on my Canon 650d

The mic in place on my Canon 650d

But fairly quickly, you’ll establish that while it does work, it does have some fairly hard to ignore issues. I was hoping, being an externally powered microphone, it would a reasonable level of gain on the output of the mic, but it appears that there isn’t a whole lot of additional amplification given to the recording level.

This isn’t ideal for most DSLR cameras with microphone inputs. They are often build with budget preamps if they are luck enough to have mic inputs at all. The high noise recordings aren’t the greatest. Usually, the best thing to do is to have a microphone that has a strong output, or run an external mixer or preamp so you can turn down the inputs on the camera.

But that’s not the big issue on this microphone.

The sound recorded to camera appears to be flipped from what you would expect, With the left channel coming from the right, and vice-versa. That is a fixable issue by either flipping the channels in post, or re wiring the mic, but the point is, you shouldn’t have to do either. Also, to make matters worse, even if you do fix it, the sound image is not properly centered. If a sound is coming directly to the front of the mic, it will appear to come from one side of the mic.

I suspect the source of this problem comes from the fact that this microphone is not actually an X/Y microphone like advertised. If you pull the mic apart (like I did), It is actually appears to be a mid/side microphone.

Being  a mid/side microphone isn’t an issue (apart from the misleading labelling), I am guessing the side capsule is not performing as an accurate figure 8 microphone, and it is biasing one side just a little bit.


Boya microphone array internals

Boya microphone internals

 

My verdict on this microphone is that its probably not worth the $30. I wouldn’t buy it again. If you have a camera with on board microphones (like most, if not all you’d consider mounting this to), You will likely get audio that is as good as, if not better than this microphone. Sure, there might be some purposes that see it being useful, like using it with the little deadcat in windy environments, that would probably yield slightly better results than the internal mic. The sound quality isn’t great, I’d say close to the on camera ones on the 650D, and it has issues with the stereo reproduction. I’d think twice about buying this mic. Save your money. for a little more you can get something a little better from a name brand like Rode, or Tascam. You’ll get much better results there.

Replacement shock mount bands

What do you do when you need replacement rubber bands for a microphone shock mount,  but cannot find them anywhere (at least anywhere that would ship to me here in Australia)?

You improvise.

I started off using  lots of small standard rubber bands,  but that didn’t work the greatest.

The old rubber bands didn't work so well

The old rubber bands didn’t work so well

Brain wave!

Pushbike inner tubes, like one massive rubber band in a circle!

Pushbike inner tubes, like one massive rubber band in a circle!

Pushbike tubes!

I can cut them to the size I need,  and they are a bit sturdier than half a dozen of the thin ones.

Just cutting slices off the tire

Just cutting slices off the tire

 

There really isn’t much to this, so the pictures will pretty much tell the story. You cut off slices of tube.

 

This is what we get

This is what we get

 

Then you mount them on the shock-mount, and you’re done.

Then we just slip them into place. As good as a bought one.

Then we just slip them into place. As good as a bought one.

 

The resulting shock mount works much better than my original effort. all the small rubber bands really didn’t hold up so well. These inner tube ones work great.

SQN 4S Series 3a Field mixer, and Attenuation cables

My new field audio kit

My new field audio kit

Recently, I added a field mixer to my collection of audio gear. I’m looking at getting more into audio production for video, and figured a field mixer was a very handy place to start. When this mixer came up on eBay, it peaked my interest. It was packing quite a bit of extras for a pretty good price. I ummed and Arred, before giving in, and buying it. Along with the mixer the extras included the bag, a break away cable, a pair of Sony headphones that look like they are as old as the mixer, and a few XLR cables. Basically an instant field audio kit. WOOT!

 

Attenuation cables

As you might be able to see in the picture, I have teamed up the mixer with my Zoom H4n, and I’ve been working on the best way to link the two devices.

The easiest way is XLR out of the mixer, into XLR of the Zoom, but due to the Zoom’s limitation of not accepting line level inputs, this connection has to be a mic level one, and I end up having to turn up the Zoom’s preamps quite a bit to get the levels where they should be. This isn’t optimal, as it introduces a lot of noise back into the recording, which is precisely what I’m avoiding by going with a mixer / recorder combo.

Best results I’ve gotten so far is coming out of the mixer line level, and attenuating the levels down until they are at a level the Zoom H4n can handle. I’m still going into the Zoom as a mic signal, but by choosing an appropriate level attenuator,  I can set the Zoom’s input levels much lower than using the mic outputs of the mixer (with the -30db cables, I can set the Zoom’s inputs to 20, instead of the 70 or 80 it’s at coming out mic level)

I messed round trying to find something that worked, scouring the internet for attenuator circuits. There is quite a lot out there that want to teach you how to work out your own values for attenuators, but it was rather difficult to find a straight forward circuit that says “Use X and Y resistors for an attenuation of Z”. Eventually, I found this Proharmonic article, which was nice enough to give some clear figures for attenuators.

 

a -30dB pad schematic

This is my rendition of a U bridge attenuator. For other values, please check out their article, linked above.

 

 

 

Comparison

To get a sense of how it performs, here are a couple of samples:

I hope this has been helpful to people out there. I’m off to record myself talking about nothing for a while, until I can find something more interesting to record.

Cheers,
Matt.

Tascam iM2 stereo microphone review

OK, so the Tascam iM2 is hardly anything new, but I just got my hands on one, so I thought I’d write a quick review

I’m testing this on my 4th generation iPod as that is the newest iDevice I own. I will make it clear that this will NOT work on a iPhone 3gs, as I’ve tried it, and the phone doesn’t detect it.

The tascam iM2 is a stereo microphone, in a Near Coincident microphone pair configuration

It is a 16 bit recorder, not 24 bit like the rode iXY, but it is a fraction of the cost. This doesn’t make it useless. 16 bit is still perfectly usable, you just need to be a little more observant of your recording levels than you would if the same device was 24bit.

 

iPod attached to iM2

iPod attached to iM2

 

Connecting the Tascam iM2 is quite easy, just it into the dock connector, and away you go. The app I’m using is Rode’s Rode Rec app. There was a Tascam one, whoever it didn’t work reliably on my ipod. It would freak out, and require a force close of the app. On going to update the app to try to fix the Tascam app, the appstore notified me that it was no longer avaliable. Rode Rec seems like a better program anyway. It does have its good and bad points, but its the best app out there I could find for this use.

Rode Rec picks the stereo mic up without a problem. The free app restricts you to 44khz which is perfectly usable, however, by updating to the pro version, it unlocks 48khz which is slightly better if your planning to use the recordings in video (The differences should be marginal, however thats technically the best way of doing things)

 

Snap and go

Snap and go

 

Back side of the microphone

Back side of the microphone

 

The main problem with using the iM2 on my iPod is that the headphone port on the iPod is on the same end as the dock connector, meaning there is no way to monitor my recordings. This is a bit of a bummer, but I guess it can be worked around, mostly by “guessing” its recording good audio. A dock connector extender might be useful here, however I don’t have one, so that isn’t tested.

So how does it sound?

I’ve uploaded a very quick comparison between the iM2 and the Zoom H4n to Soundcloud so you can listen for yourself. Its far from scientific, but it gives a clear indication of the performance of the mic.

 

What I found was that surprisingly, the Tascam has a lot less hiss than the inbuilt Zoom mics. Even when adjusting the mics to match closely in signal levels, there is a much more prominent hiss in the Zoom’s tracks.

The Zoom had a slightly better stereo image however, where the Tascam sounded slightly flatter.

 

So is it usable? I think it is. I think it should make a great recorder for impromptu recording sessions, and should be capable of great atmos tracks while tripping around. I’ll be certainly keeping this near by at all times. Which is, coincidently, an advantage of this. Its small enough that I can leave it tucked in my bag, with my ipod, and be ready to go at a moments notice. The biggest issue will be remembering to make sure the ipod’s battery is charged.

 

See the problem?

See the problem?

Stereo Recording with iSK CM-20s in ORTF

I’ve been playing around with Audio recording with my H4n, and a pair of iSK CM-20s I bought reciently from Swamp Industries

I thought the iSK microphones were interesting. There was a bit of talk online about iSK mics, but not much about the CM-20s. From what I read, the iSK microphones were pretty usable, for their price. For $65, I thought I would risk it, and have some fun. I don’t have the ears and experience do drop hundreds (or thousands) of dollars on name brand, quality mics, so these are a good price for me.

My plan for the microphones were to trial some stereo recording, teaming them up with my zoom H4n. So, I’ve been reading a bit around the interwebs on stereo recording techniques

You may say, the zoom already does stereo with its inbuild XY pair. My reading suggests that XY stereo recording doesn’t give the best stereo space in the recording, and I wanted to find out for myself.

After some reading, I decided I would start with a ORTF setup to play with. ORTF sees the microphones set 110 degrees away from each-other, with the capsules spaced 17cm apart.

ORTF mic placement, as shown on the Wikipedia page.

ORTF mic placement, as shown on the Wikipedia page.

In order to get things aligned, I’d need some way of mounting the two microphones. I had a couple of T bars kicking around, but they were too wide for an ORTF setup. One of them I got pretty close by using the center mounting hole, but then I didn’t really have anywhere good to mount it to a tripod or mic stand.

It wasn’t too hard to make a new bar thought, with a piece of aluminium bar cut to length, and some suitable holes drilled and tapped to take the 1/4 20 thread that I’m using

Unfortunately using 1/4 20 thread means I need to add several adapters to get the microphone mounts to screw on, but I was using what I had for the most part, and I had the adapters anyway.

The other issue I had was the fact that when setting the two microphones to the correct angle, and correct distance, the backs of each microphone needed to occupy the same space. To fix this solution, I had add a spacer to raise one of the microphones up about the height of one microphone, so it would then be able to pass over the top of the first microphone.

My iSK microphones, setup in ORTF, on my custom bar

My iSK microphones, setup in ORTF, on my custom bar.

One thing to note, is ensure the microphones are patched the right way around. patching them into a mixer, with the left mic panned right, and the right mic panned left will flip the sound image.

I don’t have any sample audio to post right now, But I’ll post it up here when I get a chance.

4 key midi keyboard with Basic Stamp

diy 4 button midi controller test

Here is the four button test layout, showing how simple the circuit itself really is.

So, I had this old Basic Stamp sitting here feeling unloved. I decided it would be fun to try to build a midi controller. My initial idea was a of using the jog wheels off some old VCR players as mini turntable style jog wheels, but before I get to that, I wanted to start small. I wanting to test the theory first, so I wired up the midi output to a DIN connector, and used sample code available HERE (also shows the wiring for the midi connection) to make the basic stamp output a single note over and over again, with a pause between.

With that working ok, next step was to connect some buttons to the controller, and program the buttons to output separate notes. The wiring was pretty basic, just the usual button set-up, with a pull up resistor on the input pins. The magic was mostly done in the code, which wasn’t too difficult. The code basically transmits a midi on command on each press, and a midi off command on the release of each button.

At this point, I have a 4 button midi controller. maybe useful for triggering samples or something. My next progress will be to try to get a rotary encoder to work with the setup.

I haven’t worked out a good way to host files other than photos yet, so I’ve included the code in the body of the blog below. Hopefully you’ll be able to copy and paste it if you’re interested.

' {$STAMP BS2}
' {$PBASIC 2.5}
'Mini Midi interface,
'Author Matt Ruth
'Date: 11/7/2010
'www.diydata.wordpress.com
'don't expect too many basic stamp projects from me, the plan is to put this controller to work, then leave it there.
'I only have one basic stamp, and anything I buy in future will likely be arduinos!
'future revisions:
'read the state of each button, and transmitt all states in one serial transmission, instead of individually.
' EG: $90, note1, velocity1, note2, velocity2, note3, velocity3 (http://peabody.sapp.org/class/dmp2/read/nv94_gettin_midi_with_it.pdf)
'also make the midi notes variables which are declared at the top of the program
'add data transmit led
'add jog wheels of course
'make unit as a midi foot switch trigger, getting to use more rugged switches

'following variables are used for midi output. Taken from website tutorial on midi output
outpin CON 15 ' output pin on which to send MIDI data
baudmode CON 12 ' baude mode for serout: (2500000/31250)-20 msec
 ' note that this value should be 12 for BS2. (60 otherwise)
 ' Serial rate for MIDI is 31,250 data bits/sec.
outpause CON 0 ' pause time in units of 0.4 millisec between bytes
 ' on the BS2, units are 1.0 millisec
INPUT 11'button one
INPUT 12'button two
INPUT 13'button three
INPUT 14'button four
butt_11_state VAR Bit
butt_12_state VAR Bit
butt_13_state VAR Bit
butt_14_state VAR Bit
butt_11_state = 0
butt_12_state = 0
butt_13_state = 0
butt_14_state = 0
main:

IF IN11 = 1 THEN GOSUB BUTTONone
IF IN11 = 0 THEN GOSUB BUTTONoneUP
IF IN12 = 1 THEN GOSUB BUTTONtwo
IF IN12 = 0 THEN GOSUB BUTTONtwoUP
IF IN13 = 1 THEN GOSUB BUTTONthree
IF IN13 = 0 THEN GOSUB BUTTONthreeUP
IF IN14 = 1 THEN GOSUB BUTTONfour
IF IN14 = 0 THEN GOSUB BUTTONfourUP
PAUSE(50)
GOTO main
BUTTONone:
IF (butt_11_state = 0) THEN GOSUB Onepressed
IF (butt_11_state = 1) THEN GOSUB Onestillpressed
RETURN
Onepressed:
 'send midi on note here
 SEROUT outpin, baudmode, outpause, [$90, 60, 127]
 DEBUG "1"
 butt_11_state = 1
 RETURN
Onestillpressed:
 'DEBUG ".", CR
 RETURN
BUTTONoneUP:
 IF butt_11_state = 1 THEN DEBUG ",":SEROUT outpin, baudmode, outpause, [$90, 60, 0] 'replace debug with midi off note
 butt_11_state = 0 'off note may need to be $80
 RETURN

BUTTONtwo:
IF (butt_12_state = 0) THEN GOSUB Twopressed
IF (butt_12_state = 1) THEN GOSUB Twostillpressed
RETURN
Twopressed:
 'send midi on note here
 SEROUT outpin, baudmode, outpause, [$90, 61, 127]
 DEBUG "2"
 butt_12_state = 1
 RETURN
Twostillpressed:
 'DEBUG ".", CR
 RETURN
BUTTONTwoUP:
 IF butt_12_state = 1 THEN DEBUG ",":SEROUT outpin, baudmode, outpause, [$90, 61, 0] 'replace debug with midi off note
 butt_12_state = 0 'off note may need to be $80
 RETURN
BUTTONThree:
IF (butt_13_state = 0) THEN GOSUB Threepressed
IF (butt_13_state = 1) THEN GOSUB Threestillpressed
RETURN
Threepressed:
 'send midi on note here
 SEROUT outpin, baudmode, outpause, [$90, 62, 127]
 DEBUG "3"
 butt_13_state = 1
 RETURN
Threestillpressed:
 ' DEBUG ".", CR
 RETURN
BUTTONThreeUP:
 IF butt_13_state = 1 THEN DEBUG ",":SEROUT outpin, baudmode, outpause, [$90, 62, 0] 'replace debug with midi off note
 butt_13_state = 0 'off note may need to be $80
 RETURN
BUTTONFour:
IF (butt_14_state = 0) THEN GOSUB Fourpressed
IF (butt_14_state = 1) THEN GOSUB Fourstillpressed
RETURN
Fourpressed:
 'send midi on note here
 SEROUT outpin, baudmode, outpause, [$90, 63, 127]
 DEBUG "4"
 butt_14_state = 1
 RETURN
Fourstillpressed:
 'DEBUG ".", CR
 RETURN
BUTTONFourUP:
 IF butt_14_state = 1 THEN DEBUG ",":SEROUT outpin, baudmode, outpause, [$90, 63, 0] 'replace debug with midi off note
 butt_14_state = 0 'off note may need to be $80
 RETURN

Lecci Pocket Sized DJ mixer

While browsing the pages of thinkgeek I stumbled across this little guy:

the Lecci mixer opened on my desk

The little mixer open on my desk

Incase you hadn’t already guessed, it is a little DJ mixer that runs on 4x AAA battery’s. Branded with Lecci in embossed Letters on top of the lid.

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