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8665Re: [BCD396XT] Audio

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  • MCH
    Dec 24, 2013
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      Which would explain the 100% over-rating...

      Joe M.

      > On Dec 24, 2013, at 4:32 PM, Jeffry Rehm <scanman1958@...> wrote:
      >
      >
      >
      > I would like to add that knowing there is a high probability of a wrong modulation entered then Uniden should have made absolutley sure the speaker was good enough to handle that extra load. Just in case of accidental entry.
      >
      > ------------------------------
      >> On Tue, Dec 24, 2013 1:48 PM CST Ronski45 wrote:
      >>
      >> According to Uniden's manual on the 396XT, the audio output is 310 mW across a 24 ohm load. While the speaker is rated at 0.8 W, 24 ohm. So the unit's max output is 0.31 watts while the speaker should be able to handle 0.8 watts.
      >> So your saying that the other. 49 watts or some 60% will be taken up by the modulation? No, the difference in audio is quite minor, I tried it here. Yes if one runs any component at full power for a long time will further stress a component, but its the high failure rates of speakers that these speakers just arent that great in quality.
      >>
      >> Far as saying im a database guy, was just saying about having knowledge. Yes the database isnt perfect thats why we have admins to update it. Theres nothing official about it, its all user generated. If you see a problem, all be it modulation or otherwise , submit the correction is all.
      >>
      >> MCH <mch@...> wrote:
      >>> And "slightly" exceeding the spec is all it takes to blow a speaker if
      >>> you are close to the limit to star with. Of course, "Slightly" in this
      >>> case is double the voltage which is what will happen if you monitor a
      >>> FM
      >>> transmission in NFM or AUTO mode. It may not sound like much to your
      >>> ear, but it is greatly different to your speaker. And if the speaker is
      >>>
      >>> rated at 5V (just picking numbers for this example), and the normal
      >>> maximum audio fed to it is 3V you will be fine, but doubling that means
      >>>
      >>> you would be feeding 6V which can easily damage the speaker.
      >>>
      >>> Nothing you said invalidates this technical example. I don't see what
      >>> programming knowledge or being a RR admin have to do with this. In
      >>> fact,
      >>> there are lots of incorrect entries on RR for modulation, so I guess if
      >>>
      >>> it comes down to an incorrect setting, and it was DLed from RR, that
      >>> could be a contributing factor. ;-)
      >>>
      >>> But, it is a fact that choosing the wrong modulation COULD result in
      >>> higher-then-spec levels to the speaker, and it is a fact that
      >>> higher-then-spec levels could blow a speaker. Just ask anyone who
      >>> connected a 100W stereo up to a 50W speaker (or even a 60W stereo).
      >>> It's
      >>> the exact same theory.
      >>>
      >>> Bottom line is to program the correct modulation for the channel and
      >>> you
      >>> should be able to avoid prolonged excessive levels. This is good
      >>> engineering practice, and I would hope you would agree.
      >>>
      >>> Joe M.
      >>>
      >>> Ronski45 wrote:
      >>>
      >>>
      >>> Changing modulation will only change the volumes slightly, if your
      >>> using
      >>> the wrong modulation the audio is only going to change slightly but
      >>> not
      >>> completely cut out as was mentioned. This not a modulation issue.
      >>> See upman
      >>>
      >>> http://forums.radioreference.com/uniden-scanners/144068-396t-vs-396xt-speaker.html#post1066999
      >>> "The audio level (volume) will be unbalanced. If the xmit is FM and
      >>> you
      >>> pick NFM, it will be too loud as compared to properly demodulated
      >>> signals. If it is NFM and you pick FM, it won't be loud enough."
      >>>
      >>> Wrong modulation wont make the speaker stop is all Im saying.
      >>> Ive programmed about 300 radios and am a database admin at
      >>> radioreference.
      >>>
      >>> Other thing is when the other faulty radios came to me they all said
      >>> the
      >>> same about static, missing audio at times before hand then nothing as
      >>>
      >>> was also mentioned originally .
      >>>
      >>> MCH <mch@...> wrote:
      >>>
      >>>
      >>>
      >>> As I mentioned before - just make sure you are using the correct
      >>> mode
      >>> for the channel. It's quite possible that most of these cases
      >>> come down
      >>> to the incorrect channel settings - specifically, using AUTO or
      >>> NFM on
      >>> channels that are still using FM modulation. This results in
      >>> raising
      >>> the
      >>> audio level, and while some people endorse that since it results
      >>> in
      >>> louder audio, it might result in higher-than-spec levels going to
      >>> the
      >>> speaker and causing damage.
      >>>
      >>> If in doubt, use FM and not AUTO or NFM.
      >>>
      >>> Joe M.
      >>>
      >>> Jm Adams wrote:
      >>>>
      >>>>
      >>>> Just hope Uniden got the issue figured out and current
      >>> production
      >>> has
      >>>> better speakers. I really like my scanner I purchased it back
      >>> in
      >>> July so
      >>>> now I'm on pins and needles hoping the speaker in my unit
      >>> doesn't
      >>> take
      >>>> a dump on me
      >>>>
      >>>> Sent from my iPhone
      >>>>
      >>>> On Dec 24, 2013, at 7:35, Ronski45 <ronski45@...
      >>>> <mailto:ronski45@...> wrote:
      >>>>
      >>>> This is clearly the weak point on that radio model and the
      >>> 396T.
      >>> Ive
      >>>> personally seen four, three of em being less than a week old
      >>> that the
      >>>> speaker is shot. Uniden didnt do their homework on this part
      >>> and/or
      >>>> their supplier.
      >>>> Take a look at
      >>>
      >>> http://wiki.radioreference.com/index.php/Replace_a_Blown_Speaker_in_the_396
      >>>> One thing I keep wondering on that is what holds in the
      >>> speaker?
      >>>>
      >>>> And see all the others having the same problem -
      >>>
      >>> http://www.radioreference.com/apps/Search/?cx=014732645207632841850%3Afkjydvmuoq4&q=396+speaker+replacement+&sa.x=0&sa.y=0&cof=FORID%3A9&name=Search
      >>>
      >>>
      >>> <http://www.radioreference.com/apps/Search/?cx=014732645207632841850%3Afkjydvmuoq4&q=396+speaker+replacement+&sa.x=0&sa.y=0&cof=FORID%3A9&name=Search>
      >>>>
      >>>> OB <ob1309@... <mailto:ob1309@...> wrote:
      >>>>
      >>>>
      >>>>
      >>>> Had that happen twice on the speaker on the original unit and
      >>> then
      >>>> the replacement one too. Third one is holding up nicely. All
      >>>> repaired under warranty by Uniden Australia (Sydney).
      >>>>
      >>>> OB
      >>>>
      >>>> On 24 Dec 2013, at 05:13, <K4ADD@...
      >>> <mailto:K4ADD@...>
      >>>> wrote:
      >>>>
      >>>>>
      >>>>>
      >>>>> I have no audio on my internal speaker on the 396XT.
      >>>>> External speaker is extremely low at full volume. For 2 or
      >>>>> 3 days before it quit, the audio sounded a bit distorted.
      >>>>> Anyone have similar problems? Sending it to Uniden after
      >>>>> Xmas, under warranty. Thanks gang. Ed
      >>>>
      >>>> --
      >>>> Sent from my Android phone with K-9 Mail. Please excuse my
      >>> brevity.
      >>>>
      >>>>
      >>>>
      >>>>
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      >>> 12/24/13 02:41:00
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      >>>
      >>>
      >>>
      >>>
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      >>
      >> --
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      >
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