Internal mic project for acoustic guitar!!

[tonewheelkev]

Hi All
....hoping you can help with this one?

Inspired by the MINiflex model 1 MiniFlexMic Microphone am thinking of attempting a home-made version.

The system uses mics that are "mechanically out of phase", which I understand to mean that the face AWAY from one another. So my main Q is, should the mics be OMNI or UNI directional (I'm thinking UNI!!)

On the DIGIKEY site, I found Panasonic-ECG WM-56A103

search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P9963-ND

and wondered if a pair of these might do the job.

Would appreciate your thoughts on this....and also where to get my hold of small quantities of these things in the UK

[singa]

Hi,
As stated by Digikey these mics are obsolete meaning they are no longer in production.So it's whether they have leftover stocks or not.
There are plenty of substitutes so just search around.

You play acoustic I assume so the freqency response is important
for reproducing the harmonics so a flat and wide as possible mic should be used,if you look at WM55 it's flat but it starts to roll off at 400hz. and
WM65 is even worse with high frequency peaks up to 16Khz.

So I think you should look for something better witha lower rolloff.
WM55,65 claim a low response of 100Hz. but the frequency plots tell a
different picture.As to whether unidirectional is better then an omni one,
I think it will not matter as much as you are using it "point blank",
will the polar pattern make a difference?.

Most mikes will not go low as it's designed for voice around 200hz/300hz.. and also will not go high either(some up to 10Khz.). If you check WM60A it is an omni but flat from 20hz.to 20Khz.It is a favourite of diy measurement mics for speaker testing.
The closest from WM60A is WM54.See the frequency plots but is an omni.
100hz - 16Khz real flat. Singa

[fingerboy21]

Why not use piezo transducers? I understand that they sound different, so it may not be a good suggestion.

[singa]

I rechecked WM54 again the frequency response is stated 20hz- 16khz.
so it has a good usable range. It is also a non stock item at Digikey.
It is still an omni mic.You may not need one that goes down to 20hz.
but I think it will perform alot better in the low frequency.Like
I said before it's difficult to get such good specifications even in a
unidirectional mic. if you can find one in the first place. Singa

[mickeymoose]

Attached info as to how AKG would voice a guitar.
The Mini-Flex mics I believe are omnis, I do not know if a unidirectional mic could be built that small (except for very high frequencies). I would like to understand their technical reasons for "mechanically out of phase" (it should be polarity, if anything, not phase, anyway)
E

[singa]

Originally Posted by mickeymoose

Attached info as to how AKG would voice a guitar.
The Mini-Flex mics I believe are omnis, I do not know if a unidirectional mic could be built that small (except for very high frequencies). I would like to understand their technical reasons for "mechanically out of phase" (it should be polarity, if anything, not phase, anyway)
E

Hi mickeymoose,
You have asked an interesting question,I'm not
a musician nor play any instrument but simply someone who knows a
little electronics and is also interested in how things' work ,what makes
this reality,universe work.In short what is life? Of course this is only my
opinions.

The attached pdf don't say much about the microphones and their
design.I guess they are saying they make use of electronics and physics/science to improve your ears perception or rather the recording
equipment's ability to record what the human ear will percieve as beautiful
sound.I don't know what they mean by " mechanically out of phase", I guess
they are refering to how sound waves behave when they mix together.

What is music? They are a mix of waves that bounces all over the
place and finally reach your ears and how do the ears percieve them that
makes you think,feel that there is beauty in it?

For this understanding it will require you to see what reality is all about and how you fit into the big picture.I'm sure this will turn upside down
all that you have been taught about the reality you exist or believe in.

Dan Winter is an electrical engineer who has brought this new information about how or why gravity works and it's implications to humans and their environment with regards to life,earth and the universe.

What Dan Winter is saying that all reality is fractal in nature.
If you understand what is a hologram,it's a selfsimilar entity that's let you percieve it as a 3D object.That is if you cut up the hologram into pieces,it will contain a whole miniture of itself.His main hypothesis is that fractality is the cause of gravity which Einstein did not figure out in his time.

So all this information is getting scientists all over the world(only those who are not biased and egoistic) to understand how life and biology work ,the solution to the environmental
and energy crisis/mess we have gotten ourselves in. Finally in our narrow
perspective of how or why we percieve music or sound as beautiful.

So for music to sound good you and the listening environment has to be fractal.
Do you know that the wood that is used in musical instruments are fractal?

Singa.

[tonewheelkev]

Have been away from the machine for some time.....
....but thanks to Singa and Mickeymoose for their comments so far!!

E....curious to know why you assume OMNI....?

Kev

[mickeymoose]

Kev:

Sorry I did not get back to you on this. I was winter hiking in the interior of British Columbia, no phone, no Internet, not TV only AM radio (yes Virginia, there is such a place!) and was it cold!

The reason I think these are omni directional mics is that most unis bring the sound also to the back of the diaphram to achieve the desired unidirectional effect (this can also be done by electronic wizardry). This means a physically larger assembly.
Also, I would shy away from the dual microphone approach. Unless the mics are in close proximity to each other (virtually touching) you will get some nasty comb filtering. All those good folks out there setting up lecterns with the microphones inches apart have stone ears. Comb filters are very noticeable once you know what to listen for.

Cheers, E

[Garyepe]

Hi Kev

Firstly, Guitar MIC capsule need use Uni-Directional .
Second, it have a good frequency response. As you choosed the digikey capsule is 9.7mm diamater, It is can be used . But right now many DIY or Guitar factory use the 14mm diamater capsule. Because of 14mm has a good frequency response than 9.7mm.

Please check the website in China.
lxmic


Maybe it has useful.

Gary