MK136 Super Stereo Ear | Question about Microphone

Kits Audio Hi Fi Projects
1

I recently put this MK136 together, to use it as a in-ear personel amplifier. In fact an personel silenser.
Using it when making music, to protect the ears. Keep away the load music damaging the ears you know !

But, despite it works, its sound is not very good. So I want to know what type of Mic is used.
The headphone I use is near perfect, I tested it against a MP3 player and at my amplifier. Its great !
I searched the web and asked velleman, but without getting/finding an answer.
No idea why Velleman does not provide this information, I was expecting they had a good after-sales-service, but I am wrong ?
Maybe they don’t know the type of mic, but they could tell me so.

Does anybody ever discoverd the type of mic used in this kit? The sound is very sharp now, and should be more natuaral.
I can just by a bunch an test, but that is the dummies way.
Second I can devellope a tone-regulator, but I think, the right mic does it all.

Any help is appreciated.

2

Strange, we have no trace of your previous question.
Anyway, hereby a link to the specs of the microphone:
http://www.velleman.eu/products/view/?id=11733
An answer within 23 minutes, reasonable good service if you ask me…

3

This is a microphone of less than one euro… A good mike (Sennheiser/Shure/Audio Technica/Rhode/…) costs over 100 euro and when we want a very good condenser microphone like Neumann, you can easily go above 1000 euro. For a good bass response you also need a bigger membrane so this won’t fit in this tiny microphone.

4

Thanks for this response, Velleman support.

The questions I asked to contacts I had for the netherlands.
They send me in second response to this site.
Maybe I should have done this the first time at once, but why a forum for an answer thats easy to give.

But this must be helpfull. Going to study it.

5

Okay, I read all off the datasheet, and it says the mic has a smooth response.
( would be 50 - 20000 flat in my opinion , which a lot of those types do, or 50 - 10000 )

Then why is the sound so sharp? It realy sounds like it has a build in filter for just voice-frequencies.
And then more for the higher then the lower. So my saxofone sounds realy bad and very sharp
using this “Super Ear”. So its time for the sig-gen and scope now.

And in answer to “laserguy”, an expensive mic would be great, but a smooth curve of a microphone
is smooth, no mater the size or the prise. Just like the neverending discussion about speaker boxes.

So, I now have to test the “Super Ear” with my signal-gen, to find out who is right about the sound/ or mic.
Will respond in a few days…

6

[quote=“VEL417”]Strange, we have no trace of your previous question.
Anyway, hereby a link to the specs of the microphone:
http://www.velleman.eu/products/view/?id=11733
An answer within 23 minutes, reasonable good service if you ask me…[/quote]

Okay, in response to this I have the next question.
Would the frequency response negative influenced by the use of a 10K load instead of a 1K load.
1K load is adviced for the 4.5 Vcc in the mic’s datasheet.

gevoeligheid: -61±3dB

0dB = 1V/1µbar, 1KHz
Vcc = 4.5V, RL = 1K Ohm

I could try, but knowing it better than testing without knowledge.
When it sounds better with the 1K load, then why ?
And I am not familiar with designing with Mic’s

Edit : I could ( of cource ) not wait for an answer and modified the design.
And when the RL is about 1K ohm, it definitely affects the sound.
But I do not know what is going on or why.

With the 1 K, the sound is less sharp, but the mics are also less sensitive.
I think even more then just less. I have turn up the volume to over 50% instead of about 20% with the 10K ohm.
But this is all done without measuring, only listening !
Could someone please explane.

For the volume, thats clear, the AC load is about 9 times higher…

7

Sorry, but this is a 9.99 euro gadget.
Maybe you are just expecting too much from this basic circuit.

8

Hi,

I fitted the same kit and the quality is very good for the money. Nice and basic scematics and good sound if used as specified.

I agree: € 9.99 is not a lot of money for this “gadget”.

9

Yes indeed, for the money you cannot design it yourself. ( the print i.e. )
If I had designed it myself, I incorperated a limitter. Just a few parts more.

I am trying to buy the monacor mic-cap MCE-4000, which should be a little better.
Hopefully will that solve the sharp/ metal sound.

A smaller RL 2K instead of the 10K makes it a little better, but is not what I want to live with.
A tone-control could be a solution, but I prefere a better mic, if I can find.

10

Why a better mic? I thought smooth was smooth… no matter the price…

[quote]And in answer to “laserguy”, an expensive mic would be great, but a smooth curve of a microphone
is smooth, no mater the size or the prise. Just like the neverending discussion about speaker boxes.[/quote]

What did change your mind?

11

Hi thanks for taking it serious. And why I change my mind.

First, if the characeristic of the mic is realy smooth, then I don’t know why it should be changed.
But in the details I do not have, there can be a possibility the mic is for certain frequencies more sensitive then others.

I know from some mic’s, datasheet tells more then words.
They say 100-10000 Hz ± 3dB, but when viewing the datasheet, after the 10kHz, the line goes up, almost skyhigh.
I would not say they are lying, but when you want to use this mic, you have to take measures for it.
And unfortunately there is no datasheet for this mic.
This is all referring to the “graph” – high sensitivity, flat frequency response, light –

So I think also something for the velleman mic must be the reason it does not sound “soft” or natural, but has a very mettalic background in the sound. Obviously because they are cheap ? Those parts run from .25 to 5.00 euro. Maybe this is a .25 type?
As I told, changing the RL " output impedance" helps a little, but not enough.

So I hope, after reading some comments, the Monacor MCE-4000 would be a better choice.
Somewhere I found a test between several of those mic’s

If someone has experience in this matter, please let me know.
( After all I could make a little filter, if a better mic would not help )

EDIT: forgot this,
Cheap does not always have to be bad or unusable, or fast worn. Also, expensive does not always mean its much better.
When lucky, there is often a cheap thing doing great, however you might expect more from expensive things.
Using two 100 euro mic’s to an opamp of 1 euro… I don’t like that.
Also, I had a friend, some 30 years ago, trying to get a decent sound from just a cheap mic, and even filtering did not do the job.

12

Many small condenser microphones have a boost in the high frequency range. Perhaps you can build the element in an housing that is more sensitive to bass or you can use a filter which boosts the low frequencies (a little) and attenuates mid and high?

13

I tried 2X Monacor MCE-4000, they were no better than the stock microphones.
Rigged up a Sennheiser to test and that was a lot smoother in the mid range.

Maybe for saxaphone you could try a dynamic microphone for a warmer sound?
Shouldn’t be too difficult to rig up. Watch the polarity!

Not sure if the bias power would cause problems, (the dynamics might just ignore it) but the MK136 has 50db gain
(50x amplification =50db gain?) so it should theoretically give enough gain for dynamic microphone(s).

The NE5532 is a good sounding opamp. It is to be found in many older high end mixing consoles. Maybe a 9v battery might improve the sound a little?

Mk136 is good for experimentation!

14

Hi Smithy

Thanks for your response, saves me some work and a few euro.
I will try to create an tone-control. The last option.

And the goal is a device for all kinds of sound, from voice to several woodwinds and drums.
So I already made it switchable for voice-level and music-level. Works well, although te sound is very metallic.
I tried a few other mic’s ( J-60 ) who has more response in the bass but also a bit metallic.
Must be just the kind of mic’s I think, it’s a metal foil that does the work.

15

Hi Kuifje09,

you have mentioned about J-60 microphone. Could you please send me the part number.
I was not able to find J60 anywhere. Is it from panasonic ?
what is J60 means ? is it a manufacturer part number or a series in microphone