<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class=""><br class="webkit-block-placeholder"></div><div class="">Hi All, </div><div class=""><br class=""></div><div class="">I thought you might be interested to see this.</div><div class=""><br class=""></div><div class="">Ian</div><div class=""><br class=""></div>
<div><br class=""><blockquote type="cite" class=""><div class="">Begin forwarded message:</div><br class="Apple-interchange-newline"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(0, 0, 0, 1.0);" class=""><b class="">From: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">Ian Shepherd <<a href="mailto:ian@mastering-media.co.uk" class="">ian@mastering-media.co.uk</a>><br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(0, 0, 0, 1.0);" class=""><b class="">Subject: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class=""><b class="">iPhone limiting issue solved ? (Headphone safety)</b><br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(0, 0, 0, 1.0);" class=""><b class="">Date: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">30 March 2022 at 11:30:15 BST<br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(0, 0, 0, 1.0);" class=""><b class="">To: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">Buddy Judge <<a href="mailto:buddy@apple.com" class="">buddy@apple.com</a>><br class=""></span></div><br class=""><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class=""><br class=""></div>Hi Buddy,<div class=""><br class=""></div><div class="">I emailed you recently about apparent limiting I was hearing & measuring on my iPhone when Sound Check was enabled, and I think I’ve got to the bottom of it. Apologies if this is something you’re already aware of, but it seems to be related to a setting that I didn’t previously know about:<div class=""><div class=""><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">Sounds & Haptics > Headphone Safety > Reduce Loud Sounds</div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">In a nutshell, disabling this makes Sound Check behave as I would expect, ie. no limiting when enabled. It was enabled by default for me as a European user, and set to “85 decibels”. It seems that when this setting is enabled, the increase in level due to Sound Check is sufficient to trigger this safety limiting, resulting in aggressive dynamics attenuation. Specifically, the gain was reduced by over 4 dB on the classical piece I first noticed it with, which is highly audible and unfortunate.</div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">I realise that this behaviour isn’t a bug, it’s a feature. With Sound Check enabled, the music is lifted far enough to trigger the safety limiting. For classical you could argue that this is unavoidable, because of the wide dynamic range, but as I mentioned I’ve also heard and measured it when playing back Atmos mixes with Sound Check enabled, which is a much more mainstream use-case, and seems a shame.</div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><div class="">Having said all that, the main reason for this message is that in my testing the safety limiting is being triggered independently of the volume control. I’m not in the habit of listening super-loud on my phone, and even when I turn the playback volume way down, far below 85 dB even at the loudest moments, I’m hearing the aggressive volume reductions when Reduce Loud Sounds is enabled. In fact, I can hear it affecting the level simply by changing the threshold in settings, even with the volume only a few steps up from the minimum.</div><div class=""><br class=""></div><div class="">This seems unnecessary, if its intentional. Shouldn’t the safety limiting be dependent on the actual playback level ? Otherwise it will affect the music even when the volume is low, and perhaps more importantly won’t necessarily protect users’ hearing when they choose to turn up the volume for loud music.</div><div style="font-weight: normal;" class=""><br class=""></div><div style="font-weight: normal;" class="">Two Atmos mixes where the safety limiting kicks in when Sound Check is enabled are “Chandelier” by Sia and “Roar” by Katy Perry. The classical piece I’ve been using for testing is here:</div></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><br class=""></div><div style="text-align: start; text-indent: 0px;" class=""><a href="https://music.apple.com/gb/album/the-shepherds-carol/695609721?i=695610093" class="">https://music.apple.com/gb/album/the-shepherds-carol/695609721?i=695610093</a></div><div style="text-align: start; text-indent: 0px;" class=""><br class=""></div><div style="text-align: start; text-indent: 0px;" class="">The safety limiting is clearly audible at 1:30 to 1:40</div><div style="text-align: start; text-indent: 0px;" class=""><br class=""></div><div style="text-align: start; text-indent: 0px;" class="">Again apologies if this is all something you’re already aware of!</div><div style="text-align: start; text-indent: 0px;" class=""><br class=""></div><div style="text-align: start; text-indent: 0px;" class="">Cheers,</div><div style="text-align: start; text-indent: 0px;" class=""><br class=""></div><div style="text-align: start; text-indent: 0px;" class="">Ian</div><div style="text-align: start; text-indent: 0px;" class=""><br class=""></div><div style="text-align: start; text-indent: 0px;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><br class=""></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">***<br class="">Ian Shepherd<br class=""><a href="http://mastering-media.co.uk/" class="">Mastering Media Ltd</a> - Audio Mastering, Blu-ray and DVD Excellence<br class=""><a href="http://twitter.com/ianshepherd" class="">http://twitter.com/ianshepherd</a></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><a href="http://twitter.com/ianshepherd" class=""><br class=""></a><span style="font-size: 11px;" class="">Mastering Media Ltd,</span><br style="font-size: 11px;" class=""><span style="font-size: 11px;" class="">Kemp House, 152 City Road, London, EC1V 2NX</span><br style="font-size: 11px;" class=""><span style="font-size: 11px;" class="">Registered in England and Wales </span><br style="font-size: 11px;" class=""><span style="font-size: 11px;" class="">Company No. 073500450</span><br style="font-size: 11px;" class=""><br style="font-size: 11px;" class=""><span style="font-size: 11px;" class="">Tel. +44(0)1487 842498</span></div>
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