Subject: Re: swept sine accuracy From: Jose Almagro <luegotelodigo@xxxxxxxx> Date: Fri, 6 Mar 2009 13:36:37 +0100 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>--001636e1fd01324d1c04647289b7 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Nice, here you are some references of related articles, most of them available at the web: [6] Mateljan, I.; ARTA Manual de usuario, Split 2007 [11] Kuttruff, H.; Room Acoustics; Routledge mot E F & N Spon; 2000 [14] EN ISO 3382 Ac=FAstica. Medici=F3n del tiempo de reverberaci=F3n de re= cintos con referencia a otros par=E1metros ac=FAsticos [15] Farina A.; Simultaneous measurement of impulse response and distortion with a sweptsine technique, 110th AES Convention, Paris 18- 22 February 2000. [17] Bjor O.H.; New Measurement Methods in Building Acoustics; Norsonic, Lierskogen [18] ISO 18233: Acoustics. Application of new measurement methods in building acoustics [19] M=FCller S.; Transfer-Function Measurement with Sweeps; JAES Vol. 49; 2001 [20] Morset, L.; A practical comparison of the =94new=94 swept-sine techniq= ue and MLS in measuring room impulse responses and acoustical parameters 2009/3/6 Jaime Undurraga Lucero <jaime.undurraga@xxxxxxxx> > This is an interesting paper about sweeps > SWEN M=DCLLER, PAULO MASSARANI, Transfer-Function Measurement with Sweeps= , > DIRECTOR=92S CUT INCLUDING PREVIOUSLY UNRELEASED MATERIAL > http://saturn5.com/~jwb/mueller.pdf > best regards, > jaime undurraga > > On Fri, Mar 6, 2009 at 11:49 AM, Jose Almagro <luegotelodigo@xxxxxxxx>w= rote: > >> I agree that the main problem is SNR/INR, anyway there's a >> comparison between short sweeps average and long sweeps I think it's wri= tten >> by Farina but I'm not sure, maybe by M=FCller. >> >> Best regards >> >> 2009/3/6 Piotr Majdak <piotr@xxxxxxxx> >> >>> Dear James, >>> >>> >>> If you have noise in the system (=3Droom) then the sweep duration prima= rly >>> depends on the signal-to-noise ratio (SNR) you want to achieve. This is >>> because usually, the maximum amplitude of the loudspeaker is limited. >>> Further, for exponential sweeps, the SNR may depend on frequency, f.e.,= it's >>> pink if noise is white. >>> >>> For example, we use sweeps with at least 1.5-s duration for measurement= s >>> in a sound chamber (18 dB noise) to achieve an SNR of 60 dB. For such l= ong >>> sweeps, the frequency smearing is negligible. >>> >>> However, I do not have a theoretical result... >>> >>> br, Piotr Majdak >>> >>> >>> James W. Beauchamp wrote: >>> >>>> Guys, >>>> >>>> This is a not strictly an auditory question, but it could be >>>> useful for people doing acoustic measurements. If you use a >>>> swept sine wave to measure the frequency response of a linear >>>> system, what is the limitation on the speed of the sweep in >>>> terms of how accurate the result would be? I imagine it has >>>> something to do with how smooth the actual frequency response is. If i= t >>>> has some pronounced bumps, they could be smoothed >>>> out if the sweep is too fast. >>>> >>>> In practice, you could sweep at some arbitrary rate, and then >>>> slow it by a factor of two, and if the result is the same >>>> (within an acceptable tolerance) you could say that you've >>>> converged on the solution. >>>> >>>> But I'd like to have a theoretical result. >>>> >>>> Jim Beauchamp >>>> Univ. of Illinois at Urbana-Champaign >>>> >>>> >>> >> > > > -- > Jaime Undurraga, Eng > PhD Student > ExpORL, Dept. Neurosciences > Katholieke Universiteit Leuven > Herestraat 49, bus 721 > 3000 Leuven, Belgium > Tel: +32 16 330485 > Fax: +32 16 330486 > _____________________________________________________ > http://jaime.undurraga.googlepages.com > --001636e1fd01324d1c04647289b7 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable <font face=3D"TTFFAB6DC0t00" size=3D"3"> <div align=3D"left">=A0=A0=A0 Nice, here you are some references of related= articles, most of them available at the web:</div> <div align=3D"left">=A0</div> <div align=3D"left">[6] Mateljan, I.; ARTA Manual de usuario, Split 2007</d= iv> <p align=3D"left">[11] Kuttruff, H.; Room Acoustics; Routledge mot E F &= ; N Spon; 2000</p> <p align=3D"left">[14] EN ISO 3382 Ac=FAstica. Medici=F3n del tiempo de rev= erberaci=F3n de recintos con referencia a otros par=E1metros ac=FAsticos</p= > <p align=3D"left">[15] Farina A.; Simultaneous measurement of impulse respo= nse and distortion with a sweptsine technique, 110th AES Convention, Paris = 18- 22 February 2000.</p> <p align=3D"left">[17] Bjor O.H.; New Measurement Methods in Building Acous= tics; Norsonic, Lierskogen</p> <p align=3D"left">[18] ISO 18233: Acoustics. Application of new measurement= methods in building acoustics</p> <p align=3D"left">[19] M=FCller S.; Transfer-Function Measurement with Swee= ps; JAES Vol. 49; 2001</p> <p align=3D"left">[20] Morset, L.; A practical comparison of the =94new=94 = swept-sine technique and MLS in measuring room impulse responses and acoust= ical parameters</p> <p>=A0</p></font><br><br> <div class=3D"gmail_quote">2009/3/6 Jaime Undurraga Lucero <span dir=3D"ltr= "><<a href=3D"mailto:jaime.undurraga@xxxxxxxx">jaime.undurraga@xxxxxxxx= m</a>></span><br> <blockquote class=3D"gmail_quote" style=3D"PADDING-LEFT: 1ex; MARGIN: 0px 0= px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"> <div class=3D"im">This is an interesting paper about sweeps <br>SWEN M=DCLL= ER, PAULO MASSARANI, Transfer-Function Measurement with Sweeps, DIRECTOR=92= S CUT INCLUDING PREVIOUSLY UNRELEASED MATERIAL<br><a href=3D"http://saturn5= .com/~jwb/mueller.pdf" target=3D"_blank">http://saturn5.com/~jwb/mueller.pd= f</a><br> best regards,<br>jaime undurraga<br><br></div> <div class=3D"gmail_quote"> <div class=3D"im">On Fri, Mar 6, 2009 at 11:49 AM, Jose Almagro <span dir= =3D"ltr"><<a href=3D"mailto:luegotelodigo@xxxxxxxx" target=3D"_blank">l= uegotelodigo@xxxxxxxx</a>></span> wrote:<br></div> <blockquote class=3D"gmail_quote" style=3D"PADDING-LEFT: 1ex; MARGIN: 0pt 0= pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid"> <div> <div></div> <div> <div class=3D"im"> <div>=A0=A0=A0 I agree that the main problem is SNR/INR, anyway there's= a comparison between short sweeps average and long sweeps I think it's= written by Farina but I'm not sure, maybe by M=FCller.</div> <div>=A0</div> <div>=A0=A0=A0 Best regards<br><br></div></div> <div class=3D"gmail_quote"> <div class=3D"im">2009/3/6 Piotr Majdak <span dir=3D"ltr"><<a href=3D"ma= ilto:piotr@xxxxxxxx" target=3D"_blank">piotr@xxxxxxxx</a>></span><br= ></div> <blockquote class=3D"gmail_quote" style=3D"PADDING-LEFT: 1ex; MARGIN: 0px 0= px 0px 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">Dear James,=20 <div> <div></div> <div class=3D"h5"><br><br>If you have noise in the system (=3Droom) then th= e sweep duration primarly depends on the signal-to-noise ratio (SNR) you wa= nt to achieve. This is because usually, the maximum amplitude of the loudsp= eaker is limited. Further, for exponential sweeps, the SNR may depend on fr= equency, f.e., it's pink if noise is white.<br> <br>For example, we use sweeps with at least 1.5-s duration for measurement= s in a sound chamber (18 dB noise) to achieve an SNR of 60 dB. For such lon= g sweeps, the frequency smearing is negligible.<br><br>However, I do not ha= ve a theoretical result...<br> <br>br, Piotr Majdak=20 <div> <div></div> <div><br><br>James W. Beauchamp wrote:<br> <blockquote class=3D"gmail_quote" style=3D"PADDING-LEFT: 1ex; MARGIN: 0px 0= px 0px 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">Guys,<br><br>This is= a not strictly an auditory question, but it could be<br>useful for people = doing acoustic measurements. If you use a<br> swept sine wave to measure the frequency response of a linear<br>system, wh= at is the limitation on the speed of the sweep in<br>terms of how accurate = the result would be? I imagine it has<br>something to do with how smooth th= e actual frequency response is. If it has some pronounced bumps, they could= be smoothed<br> out if the sweep is too fast.<br><br>In practice, you could sweep at some a= rbitrary rate, and then<br>slow it by a factor of two, and if the result is= the same<br>(within an acceptable tolerance) you could say that you've= <br> converged on the solution.<br><br>But I'd like to have a theoretical re= sult.<br><br>Jim Beauchamp<br>Univ. of Illinois at Urbana-Champaign<br>=A0<= br></blockquote></div></div></div></div></blockquote></div><br></div></div> </blockquote></div><br><br clear=3D"all"> <div> <div></div> <div class=3D"h5"><br>-- <br>Jaime Undurraga, Eng<br>PhD Student<br>ExpORL,= Dept. Neurosciences <br>Katholieke Universiteit Leuven <br>Herestraat 49, = bus 721<br>3000 Leuven, Belgium<br>Tel: =A0+32 16 330485<br>Fax: +32 16 330= 486<br> _____________________________________________________<br><a href=3D"http://= jaime.undurraga.googlepages.com/" target=3D"_blank">http://jaime.undurraga.= googlepages.com</a><br></div></div></blockquote></div><br> --001636e1fd01324d1c04647289b7--