Subject: Re: [AUDITORY] MIDI Drum Pads: Delay and temporal resolution From: =?Windows-1252?Q?St=F6ter=2C_Fabian-Robert?= <=?Windows-1252?Q?St=F6ter=2C_Fabian-Robert?=> Date: Tue, 18 Jun 2013 09:17:13 +0000 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>--_000_945C2BD69A884A57ACAF0659C01419D1audiolabserlangende_ Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Hi Benjamin, On Jun 17, 2013, at 6:19 PM, Benjamin Schultz <benjamin.schultz@xxxxxxxx= .CA<mailto:benjamin.schultz@xxxxxxxx>> wrote: I am currently looking at purchasing a MIDI Drum Pad for experimental resea= rch involving finger tapping. There appears to be very little information r= egarding how much of a time delay there is between the pads being tapped an= d the sound being produced (via external MIDI devices or the drum pad=92s i= nternal sequencer). To address the question of what is the total input-output latency of that s= ystem one has to consider that this varies quite a lot between different se= tups. The overall latency might consist of: * The scanning interval of the hardware controller buttons * The latency of the hardware midi controller for MIDI Out * The MIDI protocol latency * Additional latency that will be introduced when transporting MIDI over US= B. * Additional host driver latency (if you use a computer as sound generator) * =85 Although there are some sources out there like (http://www.soundonsound.com= /sos/sep02/articles/pcmusician0902.asp) that tried to measure these individ= ual factors, you better go for a measurement of the overall input-output la= tency. I recently watched a session about Android low delay audio from this= years Google I/O http://www.youtube.com/watch?v=3Dd3kfEeMZ65c They actually had a nice setup to measure the overall latency. They've used= a 2ch scope and put one channel on the output audio and the other to a sel= f made circuit that measures light intensity of a hardware led on that devi= ce. In your case you could just put a pressure sensor (piezo) on one of the= drum pads to measure the latency in a similar fashion. I=92m looking to have the smallest time delay possible (sub-millisecond wou= ld be ideal). Does anyone have any advice about the best device to use and = what kinds of time delays I should expect from the device? Their unit of pu= lses per quarter note does not appear to be very informative. I would not be surprised if most of these drum pads will have delays in the= range of 3-6 ms. With MIDI there is very little change you can get into th= e sub ms range. This might be the reason why most drum triggers are still u= sing analog transmission. Best Fabian -- Dipl.-Ing. Fabian-Robert St=F6ter International Audio Laboratories Erlangen (AudioLabs) Universit=E4t Erlangen-N=FCrnberg & Fraunhofer IIS, Audio & Multimedia Am Wolfsmantel 33 91058 Erlangen Tel.: 09131 85-20518 Fax: 09131 85-20524 Skype: faroit fabian-robert.stoeter@xxxxxxxx<mailto:fabian-robert.stoeter@xxxxxxxx= diolabs-erlangen.de> http://www.audiolabs-erlangen.de --_000_945C2BD69A884A57ACAF0659C01419D1audiolabserlangende_ Content-Type: text/html; charset="Windows-1252" Content-ID: <B2C337529304F341A9054339F252B11A@xxxxxxxx> Content-Transfer-Encoding: quoted-printable <html> <head> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3DWindows-1= 252"> <base href=3D"x-msg://77/"> </head> <body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-lin= e-break: after-white-space; "> Hi Benjamin, <div><br> </div> <div> <div apple-content-edited=3D"true"><span class=3D"Apple-style-span" style= =3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica;= font-style: normal; font-variant: normal; font-weight: normal; letter-spac= ing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; tex= t-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-s= pacing: 0px; border-spacing: 0px; -webkit-text-decorations-in-effect: none;= -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size:= medium; "> <div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line= -break: after-white-space; "> <div>On Jun 17, 2013, at 6:19 PM, Benjamin Schultz <<a href=3D"mailto:be= njamin.schultz@xxxxxxxx">benjamin.schultz@xxxxxxxx</a>> wrot= e:</div> </div> </span></div> <div><br> <blockquote type=3D"cite"> <div lang=3D"EN-US" link=3D"blue" vlink=3D"purple" style=3D"font-family: He= lvetica; font-size: medium; font-style: normal; font-variant: normal; font-= weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; te= xt-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space= : normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -we= bkit-text-stroke-width: 0px; "> <div class=3D"WordSection1" style=3D"page: WordSection1; "> <div style=3D"margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calib= ri, sans-serif; "> I am currently looking at purchasing a MIDI Drum Pad for experimental resea= rch involving finger tapping. There appears to be very little information r= egarding how much of a time delay there is between the pads being tapped an= d the sound being produced (via external MIDI devices or the drum pad=92s internal sequencer).</div> </div> </div> </blockquote> <div><br> </div> To address the question of what is the total input-output latency of that s= ystem one has to consider that this varies quite a lot between different se= tups. The overall latency might consist of:</div> <div><br> </div> <div>* The scanning interval of the hardware controller buttons</div> <div>* The latency of the hardware midi controller for MIDI Out</div> <div>* The MIDI protocol latency </div> <div>* Additional latency that will be introduced when transporting MIDI ov= er USB.</div> <div>* Additional host driver latency (if you use a computer as sound gener= ator)</div> <div>* =85</div> <div><br> </div> <div>Although there are some sources out there like (<a href=3D"http://www.= soundonsound.com/sos/sep02/articles/pcmusician0902.asp">http://www.soundons= ound.com/sos/sep02/articles/pcmusician0902.asp</a>) that tried to measure t= hese individual factors, you better go for a measurement of the overall input-output latency. I recently watch= ed a session about Android low delay audio from this years Google I/O</div> <div><br> </div> <div><a href=3D"http://www.youtube.com/watch?v=3Dd3kfEeMZ65c">http://www.yo= utube.com/watch?v=3Dd3kfEeMZ65c</a></div> <div><br> </div> <div>They actually had a nice setup to measure the overall latency. They've= used a 2ch scope and put one channel on the output audio and the other to = a self made circuit that measures light intensity of a hardware led on that= device. In your case you could just put a pressure sensor (piezo) on one of the drum pads to measure the = latency in a similar fashion.</div> <div><br> </div> <div> <blockquote type=3D"cite"> <div lang=3D"EN-US" link=3D"blue" vlink=3D"purple" style=3D"font-family: He= lvetica; font-size: medium; font-style: normal; font-variant: normal; font-= weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; te= xt-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space= : normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -we= bkit-text-stroke-width: 0px; "> <div class=3D"WordSection1" style=3D"page: WordSection1; "> <div style=3D"margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calib= ri, sans-serif; "> I=92m looking to have the smallest time delay possible (sub-millisecond wou= ld be ideal). Does anyone have any advice about the best device to use and = what kinds of time delays I should expect from the device? Their unit of pu= lses per quarter note does not appear to be very informative.</div> </div> </div> </blockquote> <div><br> </div> <div>I would not be surprised if most of these drum pads will have delays i= n the range of 3-6 ms. With MIDI there is very little change you can get in= to the sub ms range. This might be the reason why most drum triggers are st= ill using analog transmission.</div> <div><br> </div> <div>Best </div> <div>Fabian</div> <br> </div> </div> <div> <div>--<br> Dipl.-Ing. Fabian-Robert St=F6ter<br> <br> International Audio Laboratories Erlangen (AudioLabs) </div> <div>Universit=E4t Erlangen-N=FCrnberg & Fraunhofer IIS, Audio &am= p; Multimedia</div> <div>Am Wolfsmantel 33<br> 91058 Erlangen<br> Tel.: 09131 85-20518<br> Fax: 09131 85-20524<br> Skype: faroit<br> <a href=3D"mailto:fabian-robert.stoeter@xxxxxxxx">fabian-rober= t.stoeter@xxxxxxxx</a><br> <a href=3D"http://www.audiolabs-erlangen.de">http://www.audiolabs-erlangen.= de</a></div> </div> </body> </html> --_000_945C2BD69A884A57ACAF0659C01419D1audiolabserlangende_--