Updated 1 Mic pos.

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HalfBlindLefty
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Updated 1 Mic pos.

Post by HalfBlindLefty »

Due to the fact that the amp module is removed from Cybie, I had the option to test and see how micing the opening would work out.
I created a recording where I play a rhythmpart and with every repeat change the microphone config/activation
1 - Gap mic only
2 - Both mics ( gap and speaker)
3 - single speaker (right one)
4 - Both mics at speaker positions

the whole repeats twice and oh I noodled a little lead

download/file.php?id=2174
amps-mics.jpg
amps-mics.jpg (41.92 KiB) Viewed 12028 times
at the gap position all treble is down the drain. I don't think it's a usable position for recording. Not with the mic almost in the gap.
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micpos test.mp3 - (3.47 MiB)

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tytlblues
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Re: Microphone placement

Post by tytlblues »

Well, the last half of the song sounds the best to me, so I guess I like 3 & 4. I guess I missed it in an earlier post, but why did you move the guts of Cybie?
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HalfBlindLefty
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Re: Microphone placement

Post by HalfBlindLefty »

Tytl, seems you missed the topic :)
Here it is viewtopic.php?f=5&t=2139
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VikingBlues
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Re: Microphone placement

Post by VikingBlues »

I think that shows very clearly why you usually record with the two mics at the two speaker positions. :thumbsup:

The demo is like a climb up a quality ladder - 1 through to 4 - each one better than the previous one. I think you have it right that the gap mic position is lacking.
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tytlblues
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Re: Microphone placement

Post by tytlblues »

OK,up to speed now!!!!! Yep, like VB said, the demo is a climb up a quality ladder.......I'm paying close attention to mic stuff now :) Feel like a kid in candy shop!!
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HalfBlindLefty
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update Microphone placement

Post by HalfBlindLefty »

Great, just my thoughts :)
well, to keep the mic and mix things alive here is another quick one.
I put the microphones about 10 to 15cm above the upper edge of the speaker 20 cm away from the cloth and angled to a point halfway between the speaker's center and rim.
I got to this because I notices the sound difference I heard between sitting low in fron of the amp or when standing at the same spot.
When standing up I heard more middle and bass, while when I sat down I heard lots of treble to. ( I know Weber beam blockers would help)

I recorded the backing for blinded by the blues in Am this time. While recording I had the reverb knob turned off at "0"
What did I do with the mix :
1 - since I used two mono channels I had the option to shift one track a little in time (0.002 sec) to create a seperation between the two tracks.
2 - I added reverb to the tracks
3 - panned the track 80% both sides
4 - bounced the tracks to a single stereo track
5 - trimmed a couple of passes and activated loop mode.
6 - created about 4 mins of track by stretching the track using the loop function.

Then I sat down and recorded a leady kind of track again 2 mono tracks

1 - Panned the track 40% left/right
2 - Added reverb, with more roomsize, less wet signal and more dry signal ( same studio reverb as above, just other settings)
3 - adjusted the volume of the mix and created this mixdown.

That's it, here is the track :

download/file.php?id=2178

This is an example of puting the microphone in about the same line as where my ears are when I stand in front of the amp.
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Blinded_recording_jam.mp3 - (3.66 MiB)

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MichaelRobinson
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Re: Updated 1 Mic pos.

Post by MichaelRobinson »

Well..... To be franc with you I realy don't get what you are after. I maby missed a question ?? .The lead is very clear. The rythm is a bit to trebeled up.
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VikingBlues
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Re: Updated 1 Mic pos.

Post by VikingBlues »

HalfBlindLefty wrote:I got to this because I notices the sound difference I heard between sitting low in fron of the amp or when standing at the same spot.
When standing up I heard more middle and bass, while when I sat down I heard lots of treble to.
.........................................

This is an example of puting the microphone in about the same line as where my ears are when I stand in front of the amp.
.........................................

I recorded the backing for blinded by the blues in Am this time. While recording I had the reverb knob turned off at "0"
What did I do with the mix :
1 - since I used two mono channels I had the option to shift one track a little in time (0.002 sec) to create a seperation between the two tracks.
2 - I added reverb to the tracks
3 - panned the track 80% both sides
4 - bounced the tracks to a single stereo track
5 - trimmed a couple of passes and activated loop mode.
6 - created about 4 mins of track by stretching the track using the loop function.

Then I sat down and recorded a leady kind of track again 2 mono tracks
I'm thinking :think: (well as close as I can get to thinking after my first day back at work for over two weeks) that there's a sense in siting a microphone in a position that has factors in common to where you would normally be when listening to your own playing, as all your settings will have been tweaked on the basis of the sounds wher you hear them in the room.

I suppose account needs to be taken that the microphone doesn't work quite the same as the human ear, but - I think it still must have a fair degree of sense.

I normally put the microphone very close to the speaker - so of course it will not be "hearing" a very similar sound to the one that I hear when playing. The trouble is the further from the amp the microphoen is the more crucial a bigger volume is - not really an option for me.

I'm assuming your doubling up tracks and having the slight sample delay on one of them is to get extra rich and full sounds with extra space and depth.

Thanks for letting us into some of the techniques you're using. Certainly food for thought. :thumbsup:
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HalfBlindLefty
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Re: Updated 1 Mic pos.

Post by HalfBlindLefty »

@Micheal, there was no question :) I just shared a method I thought of, no more no less

@ VB, I recorded this between 21:15 and 21:45 with next to my room a youg boy asleep... so volume.. mhh not realy :D
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Re: Updated 1 Mic pos.

Post by VikingBlues »

HalfBlindLefty wrote:@ VB, I recorded this between 21:15 and 21:45 with next to my room a youg boy asleep... so volume.. mhh not realy :D
Do you recommend the use of a microphone pre-amp if the interface with my computer isn't sensitive enough to pick up the lower volumes effectively?
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HalfBlindLefty
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Re: Updated 1 Mic pos.

Post by HalfBlindLefty »

As you may remember I have a mixer between the microphone and computer interface, so effectivly I am using a preamp.
I even have a Behringer Behringer Ultragain MIC200 tube preamp that I sometimes use.
The thing you should be aware of is that most cheaper preamps will add noise and hiss to the signal.
Yes with adaptive filters you can get rid a part of that dirt on the signal. The drawback, however is that the filters, -even when working with noise samples-, will influence the recorded sound to.

To the amps volume and what the microphone can register :
Below is a screenprint of the left lead signal from the Avion (3) recording
http://soundclick.com/share.cfm?id=11856394
lead signal.jpg
lead signal.jpg (55.65 KiB) Viewed 11951 times
This part was recorded at medium volume level, so without awakening neigbour kids :dance: ( there is 20 cm concrete between my amp and him) :thumbsup:
A quick view of the signal learns that there id a lot of volume difference caused by my playing/picking dynamics.

The lower my amps volume, the less room there is between 0 and full signal for the dynamics to shine through.
If I would f.i. play at 80 DB sound level, I have ample space allowing a good difference in volume from the guitar.
Would I play at half that volume the room for the differences is split in two too.

So if the microphone isn't picking up low soundlevels to good you're in trouble, you are loosing the lower part of the dynamics. (* refering later on
In my case I would loose a lot of my softly played parts and even worse, the subtile effects I add, like softly touching a note on an adjecent string, tiny bits of vibrato etc)
With a higher volume level that will be audible without a problem.

(* If you would use a cheap mic preamp to get the poorly picked up signal amplified you can notice that the disturbing hiss and noise will be in the way of the guitar notes more than when recording with the amp on a higher volume. !!! What a mic doen'st pick up, can't be amplified either !!!!

So in the end I rather hook up the amps spdif or line out than recording at a too low volume level.

I'm not sure, but to linger on, I think a mic's specs should state the advised volume level to use when recording for best result.
( something about, membrane/coil effectiveness and the delay in going from nothing to a movement, don't ask, please :fingerscrossed: )

The above is not science, just my thought on the subject.
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VikingBlues
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Re: Updated 1 Mic pos.

Post by VikingBlues »

Difficult here in managing to find enough times when i can throttle up the amp to a good enough level that I can hear some of those subtleties you mention. There is usually a point somehwere on the volume dial that has the sound suddenly blossom and come into the room instead of hiding in the amp. If you can't get to that volume where it does that then I think you're right - you might as well record by DI.
HalfBlindLefty wrote:As you may remember I have a mixer between the microphone and computer interface, so effectivly I am using a preamp.
I even have a Behringer Behringer Ultragain MIC200 tube preamp that I sometimes use.
The thing you should be aware of is that most cheaper preamps will add noise and hiss to the signal.
I suppose the same thing applies to mixers as pre-amps - a poor quality mixer will not help.

I do have an Art Tube MP pre-amp that I've been using on a few recent mic'ed recordings. I've no idea where that stands quality wise - but it does seem to have added sufficient boost to the signal with no added noise to get an appropriate level of signal into the DAW. The Alesis iO-2 interface does not seem to have a particularly good on-board preamp for low volume input.
HalfBlindLefty wrote:The above is not science, just my thought on the subject.
Sounds like clear thinking to me. Thank you! :thumbsup: :thumbsup:
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losaavedra
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Re: Updated 1 Mic pos.

Post by losaavedra »

I'm a bit late in on this one but, on thinking about twin mic positioning, I tend to believe phase cancelling (particularly of treble) comes into play if one mic is picking up what comes off the back of the speaker(s) is recorded along with what's coming off the front of the other speaker(s). Occurs because when a speaker cone moves OUT at the front of the cab that same cone is moving IN relative to the position of the second mic. A similar effect as occurs when two side-by-side speakers are wired out of phase (plus to plus on one, plus to minus on the other) and a mic is placed in front of each. It's also why, I think, that open backed cabs (particularly with a reflective wall behind) produce differently phased sounds when a mic directly in front is coupled with another mic off to the side that is picking up more of the out of phase stuff that's bouncing off the wall where the mic in front is getting the in-phase stuff. Thus (theoretically!) two microphones pointing into the back will be in phase, as will two mics pointing at the front ... but one of each (to some degree depending on actual positioning) will tend to phase cancel. Personally I prefer closed-back cabs where hardly anything sound-wise can escape from the back!!!
Mike
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Re: Updated 1 Mic pos.

Post by MichaelRobinson »

Losaavedra.

You is absolutly right. The mic's, if one is placed behind the speaker cone and the other in front, will be 180 degrees out of fase. It's the same fenomena if two speakers are out of fase and is placed in front of each other. When one cone goes out the other on in and they will act as one cone, 180 degrees out of fase.
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Re: Updated 1 Mic pos.

Post by HalfBlindLefty »

MHH anyone gave wavelenght a second thought ?
Take the frequency range of a guitar amp convert it to wavelength range and think it over.
There is more to of then just out of phase. :wink:
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Re: Updated 1 Mic pos.

Post by MojoJim »

Another interesting perspective on out-of-phase frequency cancellation is to consider what happens when you double a track and slide one copy by a few milliseconds to fatten the sound.

If you shift the second track by 2 ms. that would put the two copies exactly out of phase for a frequency that had a cycle length (or period) of 4 ms. A period of 4 ms. corresponds to a frequency of 250 Hz. I think that would be very close to the B just below middle C.

So with a 2 ms. shift a B note would be completely cancelled out. And all higher odd harmonics of B would also be cancelled. (I think it's odd harmonics.) This is comb filtering.

I actually saw this happen. I was mixing one of the collaborations that Strummer07, Golfxzq and I have done together. I doubled the lead that Golfxzq provided and shifted one copy a bit - and one note in his lead completely vanished - actual silence where the note should have been. Golfxzq wanted to know why I had deleted a note from his solo. We tracked it down and it was cancellation due to the shifting.

At least that was our best guess at the time.
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Re: Updated 1 Mic pos.

Post by HalfBlindLefty »

Jim,

you just pinpointed what I was getting at in my last reply :) Only from another perspective and I think.... ( ok, ok I know) you're right.
I use track shifting quite a lot and always come away without any damage caused by phase problems ( lucky me)

To Loosavedra and Michael : in theory it could be only cone in/out causing sound cancelling, if amongst others microphone placement direction and distance wouldn't add to the equation.
My Cybertwin lets me change the speakers in phase/out of phase by just setting a parameter. And yes I use them both without any phase issues when recording with 2 microphones. I just take care of where/how I place them.

Besides, there are many more factors in play when looking at recording from both front and back of the speaker. To mention just one: Look ate the shape of the cone.
The back and the front differ, to say the least in shape (this radiating sound/frequencies totally different) and besides that there is a large difference in active radiating cone space. Not to mention the fact that there is no center dome in the middle of the back side but a BIG magnet and for that a totally different frequency range when compared to the front.

I'm only saying it's not a plain and simple matter of cone direction being each others oposite, there is much more to take in account :)
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HalfBlindLefty
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Re: Updated 1 Mic pos.

Post by HalfBlindLefty »

MichaelRobinson wrote:Losaavedra.

You is absolutly right. The mic's, if one is placed behind the speaker cone and the other in front, will be 180 degrees out of fase. It's the same fenomena if two speakers are out of fase and is placed in front of each other. When one cone goes out the other on in and they will act as one cone, 180 degrees out of fase.
Chances of two speakers being exactly 180 degrees out of phase are very very close to zero. Cable resistance, cable capacity even the connectos used are all in play and will influence/delay the signal and because of that prohibit 180 degrees phase shift. The worst example I ever ran into was a very thin bassless signal. Nevertheless still reasonable signal, a bit like the old cheap handheld transistor radios.

So again... in theory possibly, irl not.
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