My first recordings with two mics

[mgavrilov]

Hi! I recently bought two cheap mics - a condenser one - OneConcept Mic-700, and a dynamic one - Superlux TM58. I connect them to a Behringer Xenyx 1002, which goes into the Line in input of my PC. I record with Audacity. I experimented with the placement of the mics quite a lot - changing the distance from the instrument, placing the conderser in front of the treble, and the dynamic in front of the bass and vice versa. 
Here are two examples. The first one has the condenser in front of the treble and the dynamic in front of the bass and the two channels separated to the max in the mixer: https://www.dropbox.com/s/zlq6fcj810yq7a6/test1.mp3?dl=0
The second one has the dynamic mic in front of the bass and the condenser in front of the treble and the two channels more mixed: https://www.dropbox.com/s/bckznutmmb8733e/O sole mio1.mp3?dl=0
Both recordings are not edited at all, no EQ, no compressor, nothing, because they only get worse   . Can you give me some advice - what can I do to improve the sound, keeping in mind that i cannot change the room. I thought I could get a better sound with two mics.

 

[debra]

The first link har clear sound (only low notes so no telling how for instance an MH register would sound or how well you can capture MM). But this is nice already.
The second link gives an error when I try to access it, saying it is expired.

What can you do to improve? This is of course still a very simple recording, but you can experiment with reverb for a feeling that you are in a brighter room or small concert hall.

 

[mgavrilov]

The first link har clear sound (only low notes so no telling how for instance an MH register would sound or how well you can capture MM). But this is nice already.
The second link gives an error when I try to access it, saying it is expired.

What can you do to improve? This is of course still a very simple recording, but you can experiment with reverb for a feeling that you are in a brighter room or small concert hall.

Here is another link to the second one https://www.dropbox.com/s/bckznutmmb8733e/O sole mio1.mp3?dl=0

 

[jozz]

not sure what you mean by 'seperation'? I get both channels dead centre in either recording

if you can describe what YOU think could be better then it gets easier to respond

 

[mgavrilov]

Well, for example this is one of the best sounding recordings that i have heard and I have the same accordion  . If I could get close to this, I would be very pleased.
By separation I mean one mic all the way to R channel and the other - to the L channel.

 

[jozz]

couple of observations then:

1. are you recording into mono track? because your L/R seperation is not in the mp3 (if there is, it's certainly not panned full L and R)
that would make a slight difference towards making it sound better

2. the other thing is EQ: the YT example recording is balanced pretty nicely for my taste (although it has a lot of noise from somewhere), in your own example you would need to lower mids a bit and treble slightly to bring up the low end

3. the music itself: he hits a lot more notes than you do with this piece which makes it sound fuller, if he would play your music over his setup it would sound similar (except for the EQ-ing on his side and the better stereo scape)

 

[mgavrilov]

Thanks for your advice. I will try to change some things and I will post a new recording

 

[mgavrilov]

So this is what I managed to do with the mics facing directly forward and the accordion about 1m away from them with full channel separation: https://www.dropbox.com/s/pnxluh2t1ci761d/O sole mio2.mp3?dl=0 
Do you think this is the best so far?

 

[JerryPH]

A small video I made for someone else on how I post process my files (click HERE for that link), but one that might work well here too.

In terms of how to place the mics, that depends a lot on room environment and desired final results.  I like to have the mics in front of the accordion but about 4-6 feet apart, depending on how much separation I want in the signal.  I also like using the side-mic technique, but that takes at last one cardiod mic and one mic that can do the figure of 8 pattern.

PS, your last link... it says it is expired too.

 

[mgavrilov]

A small video I made for someone else on how I post process my files (click HERE for that link), but one that might work well here too.

In terms of how to place the mics, that depends a lot on room environment and desired final results.  I like to have the mics in front of the accordion but about 4-6 feet apart, depending on how much separation I want in the signal.  I also like using the side-mic technique, but that takes at last one cardiod mic and one mic that can do the figure of 8 pattern.

PS, your last link... it says it is expired too.

Thank you very much Jerry! I fixed the links and  tried some of your advices, they are very useful, but I still cant manage to make it better, it only gets worse   Maybe its the room, Im playing with a wall 2,5 meters in front of me.

 

[JerryPH]

A small video I made for someone else on how I post process my files (click HERE for that link), but one that might work well here too.

In terms of how to place the mics, that depends a lot on room environment and desired final results.  I like to have the mics in front of the accordion but about 4-6 feet apart, depending on how much separation I want in the signal.  I also like using the side-mic technique, but that takes at last one cardiod mic and one mic that can do the figure of 8 pattern.

PS, your last link... it says it is expired too.

Thank you very much Jerry! I fixed the links and  tried some of your advices, they are very useful, but I still cant manage to make it better, it only gets worse   Maybe its the room, Im playing with a wall 2,5 meters in front of me.

Could I see what the issue is by asking you if you would be OK with sending me the original raw music files (dropbox or an FTP/file server work best)?  Id like to see if I could do something, or make a suggestion as to what could be done to make improvements. I will also add this... your last recording is quite good, but to hear where best results would come from, Id need to hear the original untouched raw files.

Also, could you either precisely describe or include a picture of the area you are recording in and your make/model of audio interface and mics again please?  The more info you provide, the better a response I can offer.  Just send me a private message here on this forum with this info.

No pressure if you are not comfortable in doing any or all of this, of course. 

 

[debra]

I don't know whether my brain is fooling me but in the posted clips I clearly hear the treble on the left and the bass side on the right. The stereo isn't very wide (separation not good) but it is enough for headphones.

 

[jozz]

L and R are inverted indeed, they are fully seperated but there is some 'bleed'

now try to bump up the low end on the bass side and you are good to go

 

[JerryPH]

mgavrilov was kind enough to send me a couple of RAW files and I am just going though them to offer suggestions and my comments on this page are all based on the two files that I have here in front of me.  It is surprising how much one can learn from working with the original RAW files.  

The first issue is that left and right hands are individual files, but they are not single track MONO files, they are each two channel stereo files with one blank channel.  This doesnt sound like a big thing until you try working with them.  

Instead of being able to pan a channel right or left, the sound either drops or raises but stays on its side.  This makes inverting them a difficult process and one doesnt have the required control to be able to create a proper stereo sound stage

I made it so that my application (Reaper), made single track mono files of the side of the stereo file that contained the sounds.  This then let me be able to control the file properly, however, that is when I discovered two more things:

1. The basic recording levels are captured at -3.  Thats great for a final output but too high for a RAW file, it should be around -12 at the highest parts for best results and...

2. This is the hard one... though the right side microphone captures the right hand pretty well, the left side microphone captures both sides, with the right hand only slightly less than the left hand.  When played together sounds like massive bleed-through.  On top of this, because the right hand sound is captured from a different bounced source, there is a distinct time delay between the right hand as heard from the left and right channels.  Very undesireable and distracting.

In the case of the file being in this condition, there is not much that can be done to improve on it because of the bleed-through.  What needs to be done is:

1. Recreate the recording, but creating two MONO files and record at lower levels, around -12db peaks so that it gives us a great file to be able to play with in the post process.

2. The placement of the mic for the LEFT hand is in a less than optimal location... it captures too much of the right hand side likely due to bad placement and room acoustics via echo or bounce back from a close wall.  The sound from that direction needs to be reduced or blocked.

Since we are talking a music only file and not a video, microphone placement is much easier, so bring the mics much closer, like right hand mic points to the keyboard and is about 1 foot away from the accordion grill and 45degrees to the right side of the accordionist as they are looking at it.  The left mic is placed 1 foot in front of the edge of the accordion bass side and to the left far enough that the microphone points to your left hand when the bellows are extended.  The height of both is about the middle of the height of the accordion as it sits on you.  See picture below:



Here you can see my expert drawing skills (lol).  The red circles are the mics and you can tell where I suggest they be pointed.  

Now, there may need to be some more experimentation needed for best microphone placement, but this is a good place to start from.  If you are hearing a bit too much mechanical noise from the accordion, move the mics 1 foot back and 1 foot wider each side and compensate with the recording levels to again be around -12DB at the peaks.

Next is the issue of sound bouncing all around.  This happens because it is likely a small room and has bare/reflective walls.  A lot of the issues could be resolved by doing something as simple as maybe turning around to face in another direction or [font=Tahoma,Verdana,Arial,Sans-Serif]using some kind of sound absorbent material.  This can be anything from a mattress stood up on its side to thick blankets hung up on the wall to a moveable sound panel that one can make for fairly reasonable amounts (YouTube has many examples of portable sound absorbing walls made from wood and fiberglass, for example).  The grey line in the picture represents this sound absorbing material[/font]

Just doing these things will result in big improvements in the basic recording, and from there, it gives you a chance to do some post processing to improve things even more.

 

[mgavrilov]

Jerry, thank you very very much for all your work, I really apreciate it! I corrected the things that I could, experimented with the microphone positioning and I came up with somenthing new. The bleed from the condenser mic is reduced in the possible range (It is a condenser mic after all, picks up everything  ) , and I will send you the new files in PM.

 

[JerryPH]

Thanks, that would be awesome, I look forward to hearing your files with the new changes!

 

[JerryPH]

Jerry, thank you very very much for all your work, I really apreciate it! I corrected the things that I could, experimented with the microphone positioning and I came up with somenthing new. The bleed from the condenser mic is reduced in the possible range (It is a condenser mic after all, picks up everything  ) , and I will send you the new files in PM.

I saw your files and worked on making a video that explains it... I am happy that it helped you and that you gave me permission to share it here and on my website so that others could benefit.

Friends, THIS is the link to the video that I made that covers the post processing done to mgavrilovs files.  He worked out a huge improvement over his first set of files, it made working with them so much easier.

 

[Glenn]

Thanks very much guys for your interaction.
I have learned a lot from the video which was comprehensive and well presented (headphones a must). A further discussion on how to achieve left/right separation at the recording stage would be interesting. Nicely played by the way.

 

[mgavrilov]

As far as I understood, we get the best recordings by not allowing any bleed, or at least by minimizing it. I wonder then, why is that so many accordionist use a pair of condenser mics, instead of a pair of dynamic mics, which have a lot less bleed, as seen in my recording in Jerry's video (I use the dynamic mic for my right hand)?

 

[JerryPH]

Yes, it is near impossible to completely remove all of the sound bleed from the opposing hand, but condenser vs dynamic is not the deciding factor of  sensitivity.  Other factors are polar pattern, sensitivity, dynamic range, sound capture quality and other things like size of the condenser (small, medium, large, etc...), instrument dynamics,location acoustics, mic placement and so on.  There are dozens of things to take in to consideration.

Just to give your an example of a comparison between a fair quality stereo camera mics vs $20 condenser mics on a video that I took.  Note the separation when the condenser mics are phased in.  Now that people know how I post process my files, you know that I remove most of the separation, but it still comes through in this video:

[video=youtube]

No, of course this is not a fair example (camera mics vs condenser mics), but it does show what can be done with even cheap condenser mics for stereo separation (I had to decrease the sound stage as I normally do in my recordings), and some post processing.

Now, one could write a book about it, but just generally speaking, dynamic mics are great for live performances because they are less sensitive and more durable, but on the back-side, because dynamic mics are not as loud, you have to push the preamps so much more to get good quality results and that often introduces preamp noise and/or hiss.  Condensor mics are better in the recording studio (again, not in all cases, but most when taling recording instruments).

In terms of condenser mics, most pro music recording studios prefer them because of their better sounding results, higher dynamic range and greater sensitivity (because now the preamps are pushed way lower, generally resulting in much less preamp noise and greater precision in capturing the higher ranges).

Mic placement is a huge factor in controlling bleed and this took me a good evening of practice and perhaps a dozen tests and listening to the results just to learn what I liked and what I did not like, and that was already after spending perhaps 2-3 weekends playing with room placement and learning the acoustics of my room where I record.  That is all part of the fun... the learning!