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    <p>Hi Bill,</p>
    <p>I don't know about the future, but much of what is going on is
      digital, and for many good reasons. Digital offers memory, noise
      immunity, duplication, long distance communications... Analog is
      difficult and complex. Digital deals with 0 and 1. Those are
      different worlds. So for the most part the world is going digital
      but mother nature is analog (not getting into quantum physics). So
      an old guy like me, from a mostly analog world is dealing with the
      translation to and from digital. But I am not surprised that most
      of the focus is on digital.</p>
    <p>Regarding the comment about the AI: There is a professor at UC
      Berkeley named Michael I. Jordan. He is a top notch expert in
      machine learning. He is brilliant. He got the IEE award last year
      and so on (very interesting academic background)... He said that
      people talk about AI as if it there, but it does not exist. It is
      all machine learning. So AI may be another hype.<br>
    </p>
    <p>Regards</p>
    <p>Dan Lavry<br>
    </p>
    <div class="moz-cite-prefix">On 6/14/2021 8:29 PM, Bill Whitlock via
      ProAudio wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:975377134.101706.1623727797600@mail.yahoo.com">
      <meta http-equiv="content-type" content="text/html; charset=UTF-8">
      <div style="color:black;font: 12pt Arial, Helvetica, sans-serif;">This
        data sheet has become the new typical for TI ... I, too, used to
        respect the company ... but apparently all the analog people
        have departed.  My first experience was with a similar chip in
        the older TLV320 series.  The analog input specs and
        applications are like a page in a textbook that says "the
        solution to this problem is left to the reader as an exercise." 
        The data sheet for the PCM6240 is an analog joke!  Having
        recently done a project with electret mics an almost-identical
        CODEC in a Bluetooth module, I can tell you that the "mic" they
        talk about is an electret mic.  The "load" resistors set the DC
        operating point of the mic.  It's not about power transfer, it's
        about "bias" (the chip's "bias" output is generally the output
        of a very low-noise linear regulator (in the Bluetooth module my
        client chose, made by SiLabs.  Buried deep in its 70-page data
        sheet was advice to not use its internal "bias" regulator make
        one externally.
        <div><br>
        </div>
        <div>In my experience, the suppliers of cheap electret mics are
          completely clueless.  They'll tell you that supply voltage can
          be 1.5 to 6 V but that the load resistor should be, say 1 kΩ
          (with no explanation).  In fact, the pins on the mic are the
          source and drain of the internal FET.  In the engineering
          world, a FET data sheet would list Idss (drain current at zero
          gate voltage) and maximum drain voltage, among other things.
          The "recommended" load is chosen for the lowest supply
          voltage, which also results in the lowest sensitivity for the
          mic.  So I measured the drain current vs voltage for 10
          samples to determine Idss = 450 µA and max drain voltage is 7
          V for the part.  Knowing that, I used a 6 V supply and a load
          resistor 3 times the value of the "recommended" - which
          resulted in perfect class A operating point (drain voltage =
          1/2 of supply) and a 10 dB increase in sensitivity.
          Apparently, the manufacturers of these $1 mics think their
          customers are all just hobbyists and don't want to confuse
          them with real specs.  And TI follows suit in their
          application notes, again without explanation. Apparently, when
          an IC has on-board digital processing, the bit-heads get to
          write the data sheets!  I just hope the analog ignorance
          doesn't leak over into the LTC products ... I have a lot of
          respect for the innovative engineers there.</div>
        <div><br>
        </div>
        <div>I think, in some cases, we're dealing with the fact that
          analog design has fallen out of favor with universities and
          sold students on the idea that "the future is digital" ...
          but, as AI gets better won't they start writing code?  As I
          used to say in the 80s, "programmers will become the typists
          of the 21st century."</div>
        <div><br>
        </div>
        <div>Ah, now I feel better ...</div>
        <div>Bill Whitlock</div>
        <div>Ventura, CA<br>
          <br>
          <br>
          <br>
          <div
            style="font-family:arial,helvetica;font-size:10pt;color:black"><font
              size="2">-----Original Message-----<br>
              From: Dan Lavry via ProAudio <a class="moz-txt-link-rfc2396E" href="mailto:proaudio@bach.pgm.com"><proaudio@bach.pgm.com></a><br>
              To: <a class="moz-txt-link-abbreviated" href="mailto:proaudio@bach.pgm.com">proaudio@bach.pgm.com</a><br>
              Sent: Mon, Jun 14, 2021 7:48 pm<br>
              Subject: Re: [ProAudio] Microphones question<br>
              <br>
              <div id="yiv9484434567">
                <div>
                  <div>We are talking about audio fiction, so here we
                    go:</div>
                  <div>A new (year old) TI AD IC, the <span dir="ltr"
                      style="font-size:14.6667px;font-family:sans-serif;">PCM6240-Q1</span><span
                      dir="ltr"
                      style="font-size:14.6667px;font-family:sans-serif;">,
                      on figure 37 of the data sheet states:</span></div>
                  <div><font size="+3"><span dir="ltr"
                        style="font-size:14.6667px;font-family:sans-serif;"><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">Figure</span><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">37
                          and Figure</span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">38
                          show </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">how
                          to connect </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">a
                          DC-coupled </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">microphone
                        </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">for
                          a differential</span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          and single-ended</span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          input,</span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">respectively.</span><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          The</span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          value </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">of
                          the external</span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          bias </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">resistor,</span><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">R1,
                          must </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">be
                          appropriately </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">chosen 
                        </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">based</span><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          upon </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">the</span><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          microphone </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">impedance.
                        </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">For
                          a differential </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">input,</span><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">the
                          value </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">of
                          the external</span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          bias </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">resistor
                        </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">is
                          recommended</span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          to be</span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          used </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">for
                          half of the microphone </span><span dir="ltr"
style="font-size:14.6667px;font-family:sans-serif;">impedance,</span><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">whereas
                        </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">for
                          a single-ended </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">input,</span><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">the
                          external</span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          bias</span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          resistor </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">is
                        </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">recommended</span><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">
                          to be the same </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">as
                          the microphone </span><span dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">impedance.</span></span></font></div>
                  <div><font size="+3"><span dir="ltr"
                        style="font-size:14.6667px;font-family:sans-serif;"><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">They
                          are advocating matching the  load to the mic
                          output impedance (obviously for maximum power
                          transfer). That optimal setup is of course
                          only true if the mic could support such load
                          while "behaving well" (linearly, no clipping
                          or other issues). <br clear="none">
                        </span></span></font></div>
                  <div><font size="+3"><span dir="ltr"
                        style="font-size:14.6667px;font-family:sans-serif;"><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">I
                          do respect TI. It is a good company with good
                          reputation. So can we sort out facts from
                          fiction? I think the answer is simple, but I
                          will let you experts debate it if you wish. I
                          am logging off for now, I am starting to feel
                          like an old guy talking too much, and this
                          "mic loading" is a whole other issue...<br
                            clear="none">
                        </span></span></font></div>
                  <div><font size="+3"><span dir="ltr"
                        style="font-size:14.6667px;font-family:sans-serif;"><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">Regards</span></span></font></div>
                  <div><font size="+3"><span dir="ltr"
                        style="font-size:14.6667px;font-family:sans-serif;"><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;">Dan
                          Lavry<br clear="none">
                        </span></span></font></div>
                  <div><font size="+3"><span dir="ltr"
                        style="font-size:14.6667px;font-family:sans-serif;"><span
                          dir="ltr"
                          style="font-size:14.6667px;font-family:sans-serif;"><br
                            clear="none">
                        </span></span></font></div>
                  <div><span dir="ltr"
                      style="font-size:14.6667px;font-family:sans-serif;"><br
                        clear="none">
                    </span></div>
                  <div><span dir="ltr"
                      style="font-size:14.6667px;font-family:sans-serif;"><br
                        clear="none">
                    </span></div>
                  <div class="yiv9484434567yqt2774439080"
                    id="yiv9484434567yqt46091">
                    <div class="yiv9484434567moz-cite-prefix">On
                      6/14/2021 3:48 PM, Bill Whitlock via ProAudio
                      wrote:<br clear="none">
                    </div>
                    <blockquote type="cite"> </blockquote>
                  </div>
                </div>
                <div class="yiv9484434567yqt2774439080"
                  id="yiv9484434567yqt79318">
                  <div>
                    <div style="color:black;font:12pt Arial, Helvetica,
                      sans-serif;">The following article, "11 Myths
                      about Analog Noise Analysis," is a great read for
                      most of the topics raised in this thread:
                      <div><br clear="none">
                        <div><a rel="nofollow noopener noreferrer"
                            shape="rect"
                            class="yiv9484434567moz-txt-link-freetext"
                            target="_blank"
href="https://www.analog.com/en/technical-articles/11-myths-about-analog-noise-analysis.html#"
                            moz-do-not-send="true">https://www.analog.com/en/technical-articles/11-myths-about-analog-noise-analysis.html#</a></div>
                        <div><br clear="none">
                        </div>
                        <div>Bill Whitlock</div>
                        <div><br clear="none">
                        </div>
                        <div><br clear="none">
                          <div style="font-family:arial,
                            helvetica;font-size:10pt;color:black;"><font
                              size="2">-----Original Message-----<br
                                clear="none">
                              From: Dan Lavry via ProAudio <a
                                rel="nofollow noopener noreferrer"
                                shape="rect"
                                class="yiv9484434567moz-txt-link-rfc2396E"
                                ymailto="mailto:proaudio@bach.pgm.com"
                                target="_blank"
                                href="mailto:proaudio@bach.pgm.com"
                                moz-do-not-send="true"><proaudio@bach.pgm.com></a><br
                                clear="none">
                              To: David Josephson <a rel="nofollow
                                noopener noreferrer" shape="rect"
                                class="yiv9484434567moz-txt-link-rfc2396E"
                                ymailto="mailto:dlj@josephson.com"
                                target="_blank"
                                href="mailto:dlj@josephson.com"
                                moz-do-not-send="true"><dlj@josephson.com></a>;
                              <a rel="nofollow noopener noreferrer"
                                shape="rect"
                                class="yiv9484434567moz-txt-link-abbreviated"
                                ymailto="mailto:proaudio@bach.pgm.com"
                                target="_blank"
                                href="mailto:proaudio@bach.pgm.com"
                                moz-do-not-send="true">proaudio@bach.pgm.com</a><br
                                clear="none">
                              Sent: Mon, Jun 14, 2021 1:14 pm<br
                                clear="none">
                              Subject: Re: [ProAudio] Microphones
                              question<br clear="none">
                              <br clear="none">
                            </font>
                            <div id="yiv9484434567">
                              <div>
                                <div>Yes, we have to pick our battles.
                                  The 150 Ohm that is talking about has
                                  near 0 DC.</div>
                                <div>But the 6.8K resistor to 48V
                                  phantom your mic is connected to has
                                  DC... that is where material may
                                  matter. </div>
                                <div>Yes, there is more to learn every
                                  day...</div>
                                <div> Regards</div>
                                <div>Dan Lavry</div>
                                <div><br clear="none">
                                </div>
                                <div><br clear="none">
                                </div>
                                <div><br clear="none">
                                </div>
                                <div><br clear="none">
                                </div>
                                <div
                                  id="yiv9484434567composer_signature">
                                  <div
                                    style="font-size:85%;color:#575757;">Sent
                                    from Samsung Galaxy smartphone.</div>
                                </div>
                                <div><br clear="none">
                                </div>
                                <div><br clear="none">
                                </div>
                                <div
                                  style="font-size:100%;color:#000000;"
                                  align="left">
                                  <div
                                    class="yiv9484434567yqt7917953232"
                                    id="yiv9484434567yqtfd59882">
                                    <div>-------- Original message
                                      --------</div>
                                    <div>From: David Josephson via
                                      ProAudio <a rel="nofollow
                                        noopener noreferrer"
                                        shape="rect"
                                        class="yiv9484434567moz-txt-link-rfc2396E"
ymailto="mailto:proaudio@bach.pgm.com" target="_blank"
                                        href="mailto:proaudio@bach.pgm.com"
                                        moz-do-not-send="true"><proaudio@bach.pgm.com></a>
                                    </div>
                                    <div>Date: 6/14/21 12:11 PM
                                      (GMT-08:00) </div>
                                    <div>To: <a rel="nofollow noopener
                                        noreferrer" shape="rect"
                                        class="yiv9484434567moz-txt-link-abbreviated"
ymailto="mailto:proaudio@bach.pgm.com" target="_blank"
                                        href="mailto:proaudio@bach.pgm.com"
                                        moz-do-not-send="true">proaudio@bach.pgm.com</a>
                                    </div>
                                    <div>Subject: Re: [ProAudio]
                                      Microphones question </div>
                                    <div><br clear="none">
                                    </div>
                                  </div>
                                </div>
                                <div class="yiv9484434567yqt7917953232"
                                  id="yiv9484434567yqtfd98857">The
                                  microphone measurement standard
                                  recommends the use of A-weighted rms <br
                                    clear="none">
                                  noise specifications in addition to
                                  ITU-R BS.468-4, which specifies not <br
                                    clear="none">
                                  only a frequency weighting curve but a
                                  quasi-peak detector which <br
                                    clear="none">
                                  penalizes for low frequency pops and
                                  clicks, which can be a factor for <br
                                    clear="none">
                                  some poorly executed microphone
                                  designs.<br clear="none">
                                  <br clear="none">
                                  Yes, even some of the experts in the
                                  standards world talk about "low <br
                                    clear="none">
                                  noise" resistors. We have to pick our
                                  battles.<br clear="none">
                                  <br clear="none">
                                  On 6/14/2021 12:01 PM, Dan Lavry via
                                  ProAudio wrote:<br clear="none">
                                  > Excess noise is important in some
                                  cases, and it is material dependent. I
                                  <br clear="none">
                                  > agree that the 150 for the noise
                                  measurement can be "any: 150 Ohm.<br
                                    clear="none">
                                  > <br clear="none">
                                  > Regarding "A weighting", I just
                                  publish both figures. In most cases it
                                  <br clear="none">
                                  > is 2dB difference.<br
                                    clear="none">
                                  > <br clear="none">
                                  > Regards<br clear="none">
                                  > <br clear="none">
                                  > Dan Lavry<br clear="none">
                                  > <br clear="none">
                                  > On 6/14/2021 11:03 AM, Bill
                                  Whitlock via ProAudio wrote:<br
                                    clear="none">
                                  >> Dan, I'm glad you caught that
                                  one!   Noise is a "stand alone" that <br
                                    clear="none">
                                  >> needs no reference except a
                                  unit of measure - and, as frequently <br
                                    clear="none">
                                  >> omitted by marketing types, a
                                  stated bandwidth.  And I have no
                                  problem <br clear="none">
                                  >> in using weighted figures as
                                  long as it's clearly stated.<br
                                    clear="none">
                                  >><br clear="none">
                                  >> In my mind, the biggest
                                  barrier to understanding noise and its
                                  <br clear="none">
                                  >> implications is the lies,
                                  distortions, and half-truths
                                  perpetrated by <br clear="none">
                                  >> marketing folks!  A
                                  measurement, with test conditions and
                                  references <br clear="none">
                                  >> fully disclosed, is not
                                  subject to interpretation.  Sadly,
                                  many folks <br clear="none">
                                  >> are "educated" by such
                                  misleading information and will
                                  believe, for <br clear="none">
                                  >> example, that the 150 Ω
                                  resistor used for testing preamp noise
                                  must be <br clear="none">
                                  >> a special "low-noise"
                                  resistor.  In fact, thermal noise has
                                  no <br clear="none">
                                  >> dependence on the resistive
                                  material at all.  So-called
                                  "low-noise" <br clear="none">
                                  >> resistors are low in "excess
                                  noise" that occurs when DC current
                                  flows <br clear="none">
                                  >> in it - and there's a huge
                                  difference among those!  Anyone whose
                                  ever <br clear="none">
                                  >> heard me lecture is well
                                  aware that no love is lost between me
                                  and <br clear="none">
                                  >> marketing people.<br
                                    clear="none">
                                  >><br clear="none">
                                  >> Bill Whitlock<br clear="none">
                                  >><br clear="none">
                                  >><br clear="none">
                                  >> -----Original Message-----<br
                                    clear="none">
                                  >> From: Dan Lavry via ProAudio
                                  <a rel="nofollow noopener noreferrer"
                                    shape="rect"
                                    class="yiv9484434567moz-txt-link-rfc2396E"
ymailto="mailto:proaudio@bach.pgm.com" target="_blank"
                                    href="mailto:proaudio@bach.pgm.com"
                                    moz-do-not-send="true"><proaudio@bach.pgm.com></a><br
                                    clear="none">
                                  >> To: Mike Rivers <a
                                    rel="nofollow noopener noreferrer"
                                    shape="rect"
                                    class="yiv9484434567moz-txt-link-rfc2396E"
                                    ymailto="mailto:mm1100@yahoo.com"
                                    target="_blank"
                                    href="mailto:mm1100@yahoo.com"
                                    moz-do-not-send="true"><mm1100@yahoo.com></a>;
                                  <a rel="nofollow noopener noreferrer"
                                    shape="rect"
                                    class="yiv9484434567moz-txt-link-abbreviated"
ymailto="mailto:proaudio@bach.pgm.com" target="_blank"
                                    href="mailto:proaudio@bach.pgm.com"
                                    moz-do-not-send="true">proaudio@bach.pgm.com</a><br
                                    clear="none">
                                  >> Sent: Mon, Jun 14, 2021 9:27
                                  am<br clear="none">
                                  >> Subject: Re: [ProAudio]
                                  Microphones question<br clear="none">
                                  >><br clear="none">
                                  >> I think you are confusing
                                  things. EIN does not need to be
                                  measured at <br clear="none">
                                  >> full scale, and it is a real
                                  representative of the noise
                                  contributions.<br clear="none">
                                  >><br clear="none">
                                  >> Micpre noise is low and not
                                  easy to measure directly. Say you test
                                  <br clear="none">
                                  >> system can measure down to
                                  1uV, but your signal is 0.1uV. It
                                  would be <br clear="none">
                                  >> difficult to measure the
                                  noise directly.  Say you set the gain
                                  at <br clear="none">
                                  >> 60dB, the noise will become
                                  100uV, and a 1uV system can measure
                                  that. <br clear="none">
                                  >> At 40dB gain you get 10uV,
                                  still good enough to measure. In the
                                  first <br clear="none">
                                  >> case Ein is 100uV/1000, in
                                  the second case 10UV/100, both yield
                                  0.1uV <br clear="none">
                                  >> which is the real input
                                  noise.<br clear="none">
                                  >><br clear="none">
                                  >> Of course that will not hold
                                  if the design is poor. Any reasonable
                                  <br clear="none">
                                  >> design will yield very
                                  similar ein at 60dB and 40db.<br
                                    clear="none">
                                  >><br clear="none">
                                  >> Regards<br clear="none">
                                  >> Dan Lavry<br clear="none">
                                  >><br clear="none">
                                  >><br clear="none">
                                  >><br clear="none">
                                  >><br clear="none">
                                  >> Sent from Samsung Galaxy
                                  smartphone.<br clear="none">
                                  >><br clear="none">
                                  >><br clear="none">
                                  >> -------- Original message
                                  --------<br clear="none">
                                  >> From: Mike Rivers via
                                  ProAudio <a rel="nofollow noopener
                                    noreferrer" shape="rect"
                                    class="yiv9484434567moz-txt-link-rfc2396E"
ymailto="mailto:proaudio@bach.pgm.com" target="_blank"
                                    href="mailto:proaudio@bach.pgm.com"
                                    moz-do-not-send="true"><proaudio@bach.pgm.com></a><br
                                    clear="none">
                                  >> Date: 6/14/21 8:07 AM
                                  (GMT-08:00)<br clear="none">
                                  >> To: <a rel="nofollow
                                    noopener noreferrer" shape="rect"
                                    class="yiv9484434567moz-txt-link-abbreviated"
ymailto="mailto:proaudio@bach.pgm.com" target="_blank"
                                    href="mailto:proaudio@bach.pgm.com"
                                    moz-do-not-send="true">proaudio@bach.pgm.com</a><br
                                    clear="none">
                                  >> Subject: Re: [ProAudio]
                                  Microphones question<br clear="none">
                                  >><br clear="none">
                                  >> How about a little discussion
                                  on the value of knowing the EIN of a <br
                                    clear="none">
                                  >> preamp and how the figure is
                                  useful to the designer?<br
                                    clear="none">
                                  >><br clear="none">
                                  >> Here's why I ask:<br
                                    clear="none">
                                  >><br clear="none">
                                  >> When I was writing reviews
                                  regularly, EIN was (and still is)
                                  often <br clear="none">
                                  >> quoted in the product's
                                  specs. The numbers ranged from -125
                                  dBu (just <br clear="none">
                                  >> a couple) to a majority being
                                  either -127 or -128 dBu. Manufacturers
                                  <br clear="none">
                                  >> liked to tout it because it
                                  was a nice low number with "noise" in
                                  its <br clear="none">
                                  >> name. And it was always
                                  measured at a level within a dB or so
                                  of <br clear="none">
                                  >> clipping since that's it
                                  looked the best.<br clear="none">
                                  >><br clear="none">
                                  >> But unless I missed the
                                  appropriate chapter, EIN is a
                                  calculated value <br clear="none">
                                  >> - the measured noise level
                                  with the gain subtracted out. So a
                                  preamp <br clear="none">
                                  >> with 60 dB of gain that
                                  advertised EIN=-128 dBu could be
                                  expected to <br clear="none">
                                  >> put out -68 dBu of noise,
                                  measured, of course to the advantage
                                  of the <br clear="none">
                                  >> marketing department with the
                                  appropriate input termination (0, 100,
                                  <br clear="none">
                                  >> or 150 ohms usually) and
                                  output load.<br clear="none">
                                  >><br clear="none">
                                  >> So, among design engineers,
                                  what's the big deal about EIN? Is
                                  there a <br clear="none">
                                  >> better way of measuring it
                                  that's more meaningful? And if you can
                                  <br clear="none">
                                  >> squeeze another dB of EIN out
                                  of a design, how significant will this
                                  <br clear="none">
                                  >> be to the user?  I<br
                                    clear="none">
                                  >><br clear="none">
                                  >> , know "it depends."<br
                                    clear="none">
                                  >><br clear="none">
                                  >> -- <br clear="none">
                                  >> For a good time
                                  callhttp://mikeriversaudio.wordpress.com 
                                  <a rel="nofollow noopener noreferrer"
                                    shape="rect"
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                                    moz-do-not-send="true"><http://mikeriversaudio.wordpress.com/></a><br
                                    clear="none">
                                  >>
                                  _______________________________________________<br
                                    clear="none">
                                  >> ProAudio mailing list<br
                                    clear="none">
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                                    noreferrer" shape="rect"
                                    class="yiv9484434567moz-txt-link-abbreviated"
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                                    href="mailto:ProAudio@bach.pgm.com"
                                    moz-do-not-send="true"><mailto:ProAudio@bach.pgm.com></a><br
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                                  >><br clear="none">
                                  >>
                                  _______________________________________________<br
                                    clear="none">
                                  >> ProAudio mailing list<br
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                            <div class="yiv9484434567yqt7917953232"
                              id="yiv9484434567yqtfd17519">_______________________________________________<br
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                    <fieldset class="yiv9484434567mimeAttachmentHeader"></fieldset>
                    <pre class="yiv9484434567moz-quote-pre">_______________________________________________
ProAudio mailing list
<a rel="nofollow noopener noreferrer" shape="rect" class="yiv9484434567moz-txt-link-abbreviated" ymailto="mailto:ProAudio@bach.pgm.com" target="_blank" href="mailto:ProAudio@bach.pgm.com" moz-do-not-send="true">ProAudio@bach.pgm.com</a>
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</pre>
                  </div>
                </div>
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              <div class="yqt2774439080" id="yqt80081">_______________________________________________<br
                  clear="none">
                ProAudio mailing list<br clear="none">
                <a shape="rect" ymailto="mailto:ProAudio@bach.pgm.com"
                  href="mailto:ProAudio@bach.pgm.com"
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                  target="_blank" moz-do-not-send="true">http://bach.pgm.com/mailman/listinfo/proaudio</a><br
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            </font></div>
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      <br>
      <fieldset class="mimeAttachmentHeader"></fieldset>
      <pre class="moz-quote-pre" wrap="">_______________________________________________
ProAudio mailing list
<a class="moz-txt-link-abbreviated" href="mailto:ProAudio@bach.pgm.com">ProAudio@bach.pgm.com</a>
<a class="moz-txt-link-freetext" href="http://bach.pgm.com/mailman/listinfo/proaudio">http://bach.pgm.com/mailman/listinfo/proaudio</a>
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