Re: Driving headphones at high peak levels (=?UTF-8?Q?Pawe=C5=82_G=C3=B3ralski?= )

Subject: Re: Driving headphones at high peak levels From: =?UTF-8?Q?Pawe=C5=82_G=C3=B3ralski?= <p.goralski@xxxxxxxx> Date: Fri, 12 Dec 2014 18:20:05 +0100 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY> --==o2.pl-WebMail-c1ee944.16a048c0.94487== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi=20Bob. In=20my=20opinion=20the=20real=20hurdle=20will=20be=20getting=20yourself=20= a=20good=20pair=20of=20headphones. I=20was=20a=20listener=20in=20an=20psychoacoustic=20experiment=20regardin= g=20auditory=20filters=20at=20high=20frequencies.=20The=20headphones=20ne= eded=20to=20deliver=20quite=20high=20signals=20(band=20noise)=20and=20bot= h=20HDA200=20and=20HD650=20would=20start=20to=20produce=20audible=20disto= rtion=20before=20reaching=20the=20masking=20threshhold.=20We=20then=20gav= e=20a=20try=20to=20AKG=20k701=20wihtout=20much=20thought=20put=20into=20i= t=20and=20they=20seemed=20to=20work=20better.=20But=20there=20might=20hav= e=20been=20some=20issues=20with=20the=20impedance=20mismatching=20for=20k= 701. And=20as=20far=20as=20I=20know=20I=20don't=20have=20impaired=20hearing=20= so=20the=20situation=20might=20get=20worse=20for=20listeners=20with=20imp= aired=20hearing. So=20selecting=20a=20good=20sound=20card=20is=20important,=20but=20gettin= g=20really=20good=20headphones=20is=20even=20more=20crucial=20-=20especia= lly=20If=20you=20plan=20on=20visiting=20higher=20output=20levels. Cheers Pawe=C5=82 Dnia=207=20grudnia=202014=2014:29=20Bob=20Carlyon=20<Bob.Carlyon@xxxxxxxx= BU.CAM.AC.UK>=20napisa=C5=82(a): Dear=20list,I=20am=20involved=20in=20a=20project=20where=20we=20are=20pla= y=20some=20pulsatile=20stimuli=20to=20listeners=20who=20may=20have=20a=20= hearing=20loss.=20To=20do=20so=20we=20need=20to=20produce=20high=20peak=20= levels=20in=20order=20to=20obtain=20sufficient=20loudness.=20The=20test=20= will=20be=20run=20in=20different=20clinics=20worldwide,=20which=20means=20= both=20that=20we=20can=E2=80=99t=20choose=20an=20expensive=20solution,=20= and=20that,=20at=20least=20preferably,=20we=20should=20be=20using=20USB=20= devices=20=E2=80=93=20although=20I=20realise=20that=20the=20voltage=20pro= vided=20by=20the=20USB=20will=20impose=20some=20limitations.=C2=A0I=20wou= ld=20be=20grateful=20for=20suggestions=20on=20how=20to=20maximise=20the=20= audio=20output,=20and=20list=20below=20the=20general=20options=20&=20= limitations=20as=20I=20see=20it=C2=A0Choose=20a=20sensitive=20transducerA= t=20present=20we=20are=20using=20Sennheiser=20HD650s=20which=20produce=20= about=20106=20dB=20SPL/V=20for=20a=201-kHz=20sinusoid.=20In=20a=20recent=20= post=20Mike=20Stone=20mentioned=20the=20HDA200=20which=20produces=20117=20= dB=20SPL/V,=20but=20that=20is=20very=20expensive;=20does=20anyone=20know=20= of=20cheaper=20headphones=20that=20are=20also=20very=20sensitive?=20Anoth= er=20option=20is=20to=20use=20insert=20earphones=20such=20as=20the=20Etym= otic=20ER=205.=20However=20the=20highest=20input=20impedance=20these=20co= me=20in=20is=2050=20ohms,=20which=20is=20similar=20to=20the=20output=20im= pedance=20of=20the=20USB=20sound=20cards=20I=20have=20tried=20(see=20belo= w)=C2=A0Choose=20a=20USB=20sound=20card=20with=20=E2=80=9Cbetter=E2=80=9D= =20specificationsThe=20USB=20sound=20cards=20that=20I=20have=20seen=20hav= e=20output=20impedances=20of=20around=2050=20ohms=20or=20higher,=20making= =20them=20unsuitable=20for=20driving=20low=20impedance=20phones,=20so=20a= =20low-output-impedance=20USB=20sound=20card=20with=20decent=20maximum=20= output=20would=20be=20one=20solutionThe=20two=20cards=20that=20I=20have=20= been=20calibrating=20differ=20by=20more=20than=208=20dB=20in=20the=20maxi= mum=20output=20they=20can=20produce=20into=20a=20300-ohm=20load=20without= =20clipping=20=E2=80=93=20the=20winner=20being=20the=20Roland=20Quad=20ca= pture=20at=20a=20peak=20value=20of=20approx..=202.6V.=20=C2=A0If=20anyone= =20knows=20of=20a=20USB=20sound=20card=20that=20would=20exceed=20this,=20= or=20even=20match=20it=20at=20a=20cheaper=20price=20(The=20Roland=20is=20= about=20=C2=A0UK=C2=A3150,=20so=20say=20US$225)=20I=20would=20be=20glad=20= to=20hear=20of=20it=C2=A0Use=20a=20separate=20headphone=20amplifierDoes=20= anyone=20have=20experience=20of=20relatively=20inexpensive(say=20<=20U= S$150)=20=C2=A0headphone=20amps?=20As=20mentioned=20above=20something=20U= SB=20driven=20would=20be=20ideal,=20but=20maybe=20at=20a=20pinch=20we=20c= ould=20use=20something=20driven=20by=20a=2012V=20power=20supply=20using=20= a=20mains=20adaptor.=20One=20option=20(just=20gleaned=20from=20the=20inte= rnet)=20is=20the=20ART=20headamp=204,=20but=20I=20have=20no=20experience=20= with=20this=20and=20so=20if=20anyone=20has=20calibrated=20any=20such=20de= vice=20and=20has=20suggestions=20again=20I=E2=80=99d=20be=20grateful=C2=A0= =C2=A0I=E2=80=99d=20be=20happy=20to=20collate=20responses=20and=20post=20= them=20to=20the=20list=C2=A0=C2=A0Cheers=C2=A0Bob=C2=A0=C2=A0Dr.=20Bob=20= CarlyonDeputy=20DirectorMRC=20Cognition=20&=20Brain=20Sciences=20Unit= 15=20Chaucer=20Rd.Cambridge=20CB2=207EFEnglandTel:=20+44=20(0)1223=203552= 94Fax:=20+44=20(0)1223=20359062www.mrc-cbu.cam.ac.ukSee=20also=20theCambr= idge=20Hearing=20Group=C2=A0 --==o2.pl-WebMail-c1ee944.16a048c0.94487== Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi=20Bob.<br=20/>In=20my=20opinion=20the=20real=20hurdle=20will=20be=20ge= tting=20yourself=20a=20good=20pair=20of=20headphones.<br=20/>I=20was=20a=20= listener=20in=20an=20psychoacoustic=20experiment=20regarding=20auditory=20= filters=20at=20high=20frequencies.=20The=20headphones=20needed=20to=20del= iver=20quite=20high=20signals=20(band=20noise)=20and=20both=20HDA200=20an= d=20HD650=20would=20start=20to=20produce=20audible=20distortion=20before=20= reaching=20the=20masking=20threshhold.=20We=20then=20gave=20a=20try=20to=20= AKG=20k701=20wihtout=20much=20thought=20put=20into=20it=20and=20they=20se= emed=20to=20work=20better.=20But=20there=20might=20have=20been=20some=20i= ssues=20with=20the=20impedance=20mismatching=20for=20k701.<br=20/>And=20a= s=20far=20as=20I=20know=20I=20don't=20have=20impaired=20hearing=20so=20th= e=20situation=20might=20get=20worse=20for=20listeners=20with=20impaired=20= hearing.<br=20/>So=20selecting=20a=20good=20sound=20card=20is=20important= ,=20but=20getting=20really=20good=20headphones=20is=20even=20more=20cruci= al=20-=20especially=20If=20you=20plan=20on=20visiting=20higher=20output=20= levels.<br=20/><br=20/>Cheers<br=20/>Pawe=C5=82<br=20/><br=20/><br=20/>Dn= ia=207=20grudnia=202014=2014:29=20Bob=20Carlyon=20<Bob.Carlyon@xxxxxxxx= .CAM.AC.UK>=20napisa=C5=82(a):<br=20/><br=20/> <blockquote=20style=3D"font-size:=2012px;=20padding-left:=201em;=20margin= -left:=201em;=20margin-bottom:=200px;=20border-left:=20#ccc=202px=20solid= ;"> <div=20id=3D"msg"> <div=20id=3D"msg-body"> <div=20class=3D"WordSection1"> <p=20class=3D"MsoNormal">Dear=20list, <p=20class=3D"MsoNormal">I=20am=20involved=20in=20a=20project=20where=20w= e=20are=20play=20some=20pulsatile=20stimuli=20to=20listeners=20who=20may=20= have=20a=20hearing=20loss.=20To=20do=20so=20we=20need=20to=20produce=20hi= gh=20peak=20levels=20in=20order=20to=20obtain=20sufficient=20loudness.=20= The=20test=20will=20be=20run=20in=20different=20clinics=20worldwide,=20wh= ich=20means=20both=20that=20we=20can=E2=80=99t=20choose=20an=20expensive=20= solution,=20and=20that,=20at=20least=20preferably,=20we=20should=20be=20u= sing=20USB=20devices=20=E2=80=93=20although=20I=20realise=20that=20the=20= voltage=20provided=20by=20the=20USB=20will=20impose=20some=20limitations.= <p=20class=3D"MsoNormal">=C2=A0 <p=20class=3D"MsoNormal">I=20would=20be=20grateful=20for=20suggestions=20= on=20how=20to=20maximise=20the=20audio=20output,=20and=20list=20below=20t= he=20general=20options=20&=20limitations=20as=20I=20see=20it <p=20class=3D"MsoNormal">=C2=A0 <p=20class=3D"MsoNormal">Choose=20a=20sensitive=20transducer</str= ong> <p=20class=3D"MsoNormal">At=20present=20we=20are=20using=20Sennheiser=20H= D650s=20which=20produce=20about=20106=20dB=20SPL/V=20for=20a=201-kHz=20si= nusoid.=20In=20a=20recent=20post=20Mike=20Stone=20mentioned=20the=20HDA20= 0=20which=20produces=20117=20dB=20SPL/V,=20but=20that=20is=20very=20expen= sive;=20does=20anyone=20know=20of=20cheaper=20headphones=20that=20are=20a= lso=20very=20sensitive?=20Another=20option=20is=20to=20use=20insert=20ear= phones=20such=20as=20the=20Etymotic=20ER=205.=20However=20the=20highest=20= input=20impedance=20these=20come=20in=20is=2050=20ohms,=20which=20is=20si= milar=20to=20the=20output=20impedance=20of=20the=20USB=20sound=20cards=20= I=20have=20tried=20(see=20below) <p=20class=3D"MsoNormal">=C2=A0 <p=20class=3D"MsoNormal">Choose=20a=20USB=20sound=20card=20with=20= =E2=80=9Cbetter=E2=80=9D=20specifications <p=20class=3D"MsoNormal">The=20USB=20sound=20cards=20that=20I=20have=20se= en=20have=20output=20impedances=20of=20around=2050=20ohms=20or=20higher,=20= making=20them=20unsuitable=20for=20driving=20low=20impedance=20phones,=20= so=20a=20low-output-impedance=20USB=20sound=20card=20with=20decent=20maxi= mum=20output=20would=20be=20one=20solution <p=20class=3D"MsoNormal">The=20two=20cards=20that=20I=20have=20been=20cal= ibrating=20differ=20by=20more=20than=208=20dB=20in=20the=20maximum=20outp= ut=20they=20can=20produce=20into=20a=20300-ohm=20load=20without=20clippin= g=20=E2=80=93=20the=20winner=20being=20the=20Roland=20Quad=20capture=20at= =20a=20peak=20value=20of=20approx..=202.6V.=20=C2=A0If=20anyone=20knows=20= of=20a=20USB=20sound=20card=20that=20would=20exceed=20this,=20or=20even=20= match=20it=20at=20a=20cheaper=20price=20(The=20Roland=20is=20about=20=C2=A0= UK=C2=A3150,=20so=20say=20US$225)=20I=20would=20be=20glad=20to=20hear=20o= f=20it <p=20class=3D"MsoNormal">=C2=A0 <p=20class=3D"MsoNormal">Use=20a=20separate=20headphone=20amplifi= er <p=20class=3D"MsoNormal">Does=20anyone=20have=20experience=20of=20relativ= ely=20inexpensive(say=20<=20US$150)=20=C2=A0headphone=20amps?=20As=20m= entioned=20above=20something=20USB=20driven=20would=20be=20ideal,=20but=20= maybe=20at=20a=20pinch=20we=20could=20use=20something=20driven=20by=20a=20= 12V=20power=20supply=20using=20a=20mains=20adaptor.=20One=20option=20(jus= t=20gleaned=20from=20the=20internet)=20is=20the=20ART=20headamp=204,=20bu= t=20I=20have=20no=20experience=20with=20this=20and=20so=20if=20anyone=20h= as=20calibrated=20any=20such=20device=20and=20has=20suggestions=20again=20= I=E2=80=99d=20be=20grateful <p=20class=3D"MsoNormal">=C2=A0 <p=20class=3D"MsoNormal">=C2=A0 <p=20class=3D"MsoNormal">I=E2=80=99d=20be=20happy=20to=20collate=20respon= ses=20and=20post=20them=20to=20the=20list <p=20class=3D"MsoNormal">=C2=A0 <p=20class=3D"MsoNormal">=C2=A0 <p=20class=3D"MsoNormal">Cheers <p=20class=3D"MsoNormal">=C2=A0 <p=20class=3D"MsoNormal">Bob <p=20class=3D"MsoNormal">=C2=A0 <p=20class=3D"MsoNormal">=C2=A0 <p=20class=3D"MsoNormal">Dr.=20Bob=20Carlyon <p=20class=3D"MsoNormal">Deputy=20Director <p=20class=3D"MsoNormal">MRC=20Cognition=20&=20Brain=20Sciences= =20Unit <p=20class=3D"MsoNormal">15=20Chaucer=20Rd. <p=20class=3D"MsoNormal">Cambridge=20CB2=207EF <p=20class=3D"MsoNormal">England <p=20class=3D"MsoNormal">Tel:=20+44=20(0)1223=20355294 <p=20class=3D"MsoNormal">Fax:=20+44=20(0)1223=20359062 <p=20class=3D"MsoNormal"><a=20href=3D"http://www.mrc-cbu.cam.ac.uk/= "=20target=3D"=5Fblank">www.mrc-cbu.cam.ac.uk</a> <p=20class=3D"MsoNormal">See=20also=20the <p=20class=3D"MsoNormal"><a=20href=3D"www-hearing-research.eng.cam.= ac.uk/Main/WebHome"=20target=3D"=5Fblank">Cambridge=20Hearing=20Group</a>= <p=20class=3D"MsoNormal">=C2=A0 </div> </div> </div> </blockquote> <br=20/><br=20/> --==o2.pl-WebMail-c1ee944.16a048c0.94487==--

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Electrical Engineering Dept., Columbia University