Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!nntp.club.cc.cmu.edu!micro-heart-of-gold.mit.edu!bloom-beacon.mit.edu!panix!MIX!Blackbird From: billy@MIX.COM Newsgroups: comp.sys.mac.system Subject: Re: Experience with Smith Micro? Date: Thu, 6 Feb 2014 18:12:06 +0000 (UTC) Organization: PANIX Public Access Internet and UNIX, NYC Lines: 42 Message-ID: References: <7hbnymytl5.fsf@ethel.the.log> <201402050503417065-savageduck1@REMOVESPAMmecom> NNTP-Posting-Host: panix5.panix.com X-Trace: reader2.panix.com 1391710326 11696 166.84.1.5 (6 Feb 2014 18:12:06 GMT) X-Complaints-To: abuse@panix.com NNTP-Posting-Date: Thu, 6 Feb 2014 18:12:06 +0000 (UTC) Xref: csiph.com comp.sys.mac.system:56142 J Burns writes: > Headphone jacks used to have a 220-ohm resistor in series. I listened > to my Koss Pro4AAs for years that way. Then I read about damping > factors. I don't know what you read, but if it wasn't this... http://diyspeakers.net/Articles/Richard%20Pierce%20DAMPING%20FACTOR.pdf ...I highly recommend you take a look now. | 6 CONCLUSIONS | | There may be audible differences that are caused by non-zero source | resistance. However, this analysis and any mode of measurement and | listening demonstrates conclusively that it is not due to the | changes in damping the motion of the cone at the point where it's at | its most uncontrolled: system resonances. We have not looked at the | frequency-dependent attenuative effects of the source resistance, | but that's not what the strident claims are about. | | Rather, the people advocating the importance of high damping factors | must look elsewhere for a culprit: motion control at resonance | simply fails utterly to explain the claimed differences. > So I used a resistor network to feed my phones with 2 ohms. What an > improvement! A piece of wire (essentially zero ohms) would have had the same effect. Headphone amplifiers need a load - generally about 32~75 ohms - to work well. This is a common problem in my work, where someone wants to feed music from a phone or laptop computer into a PA system. If a cable is plugged into the headphone output jack, going to a relatively high impedance inputs, a suitable load for the outputs needs to be provided. I've lost count of how many cables I've built for this... Billy Y.. -- sub #'9+1 ,r0 ; convert ascii byte add #9.+1 ,r0 ; to an integer bcc 20$ ; not a number