|
|
Posted by Smarty on 04/28/07 02:25
Four more thoughts:
1, The MTS-4 has both an audio output jack on the rear which will allow you
to hear / scope the audio before it hits the modulator. Connect up at this
point to determine if the compander is at fault.
2. The Cadco modulators have an internally defeatable pre-emphasis curve
which may be set for compensating highs. Be sure this is set correctly.
3. The MTS has a lot of output voltage and could be adding 10 DB or more
gain after beyond the companding. Make sure that your compander output is
not way beyond your modulator's input range (this is nappy's point, but is
more specifically relevant since the MTS puts out a big signal....)
4. Lastly, the compander has a remarkably narrow 5Khz bandwidth, quite
adequate for a call in talk-show telephone line or AM radio microphone, but
not much else. Take the compander out of the circuit altogether and see how
the wider bandwidth audio sounds with respect to sibilance and let us know.
We should then be able to help you further.
Smarty
"Smarty" <nobody@nobody.com> wrote in message
news:msydnR2V7-v7Na_bnZ2dnUVZ_riknZ2d@adelphia.com...
> If what you are experiencing is truly sibilance, the very specific
> unnatural emphasis given to fricative sounds like "s" and "f", rather than
> distortion, the likely culprit is an uneven frequency response which
> places undue emphasis on mid to high frequency energy somewhere in the
> modulation chain. It is commonly associated with devices which have very
> irregular frequency/phase characteristics, such as a microphone with a
> very peaked response in the upper vocal frequencies, or an equalization
> curve which has been improperly set. Companders and modulators are not the
> typical cause, although a defect in either can cause excessive treble
> exaggerations which produce sibilance on fricative sounds.
>
> As nappy states, you will need to get into the modulation chain at
> intermediate points with a scope, a reliable reference playback system, or
> both, while driving the system with a known, balanced audio source. There
> is no way to easily diagnose the problem otherwise, at least not that I am
> aware of.
>
> Smarty
>
> "Rick Merrill" <rick0.merrill@NOSPAM.gmail.com> wrote in message
> news:fo2dnUOF4ek19q_bnZ2dnUVZ_jWdnZ2d@comcast.com...
>> nappy wrote:
>>> "Rick Merrill" <rick0.merrill@NOSPAM.gmail.com> wrote in message
>>> news:YYKdnXtRaNbzoq_bnZ2dnUVZ_tidnZ2d@comcast.com...
>>>> Richard Crowley wrote:
>>>>> "Rick Merrill" wrote ...
>>>>>> My TV station (PEG/public access) has a lot of similiance.
>>>>>> There is a CADCO modulator after an MTS-4 compander. How do
>>>>>> I tune the system to address sibiliance???
>>>>> Do you hear the problem on ALL program material?
>>>> Yes.
>>>>
>>>>> Wouldn't the maintenance engineer handle this?
>>>
>>>
>>> so if ALL of the audio [emanating] from the station sounds too sibilant
>>> it is likely that one of the stages on the way to the transmitter is
>>> either being compressed to far and then amplified or there is too much
>>> gain. Interrupt the signal and find out where it is happening
>>
>>
>> You really cannot separate the MTS-4 (compander) from the Cadco
>> (modulator). ... darned analog components!
>
>
Navigation:
[Reply to this message]
|