The membrane of a omni faces "nothing", except "vacuum". There is no air
behind it. The back is closed, or has a "can" behind which size is tuned so
that it "helps" the membrane moving, still maintaining a "flat" frequency
curve.
Klas.
Vicky,
When you close the vents, the back of the membrane will face a can, with a
resonance frequency. Closing the vents will drastically change all
specifications of the microphone.
Klas.
At 14:55 2002-02-09 +1100, you wrote:
>Walt and All,
>
>I tried closing the back 4 rows of the ME64 cardioid mic (just by gripping
>the mic in my hand), to see if it would respond more like an omni mic. I
>used a transistor radio as the sound source, and listened through
>headphones. For a front on comparison of blocked and unblocked, there
>seemed to be a higher frequency boost when blocked. For a side-on
>comparison, the blocked off version had somewhat more sensitivity than the
>unblocked version, but nothing like as clear as front on. So there must be
>something else happening in the ME 62. I wonder what?
>
>Vicki Powys
>Australia
>
>
>
>
>> on 9/2/02 12:00 PM, Walter Knapp at wrote:
>
>> A omni should sound loud and clear from all sides.
>>
>> Sennheiser has pdf's of the specs and so on for the mics on their site.
>> Looking at those, you want to close the back 4 rows of slots. With tape
>> that's pretty soundproof.
>>
>> Those back holes probably let in sound that kills the sound from the
>> back by phase interference.
>>
>> The same pdf's include the polar patterns for the two mics.
>>
>> You might also try orienting your mics vertical in a spaced
>> configuration. Looking at the polar pattern, this would result in a
>> sensitivity penalty at ground level, but that would be the same all
>> around. You would also hurt your high frequency response by a fair
>> amount. But you should then get sound from all around like a omni does.
>>
>> Walt
>>
>>
>
>> Vicki Powys wrote:
>>
>>> I sure do relate to "low end - good quality", Rich! I tried your conversion
>>> trick, to turn a ME 64 cardioid into a ME 62 omni. Sennheiser will be very
>>> pleased to know that it didn't work!! What a disappointment!
>>>
>>> As I understand it, an omni mic should sound as loud and clear from both
>>> front and sides, (if for example, you were speaking into it.) Is that how
>>> your ME 62 responds Rich? I tried many combinations of blocking various
>>> vents on the ME 64, but I always had a cardioid effect, i.e. loud and clear
>>> at the front, but much less at the side.
>>>
>>> I will look at Sennheiser's website for more clues.
>>
>>
>> To unsubscribe from this group, send an email to:
>>
>>
>>
>>
>> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>>
>>
>>
>
>
>
>To unsubscribe from this group, send an email to:
>
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
This outgoing e-mail is scanned for viruses with Norton 2002
Telinga Microphones, Botarbo,
S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01
email:
________________________________________________________________________
________________________________________________________________________
|