Subject: [AUDITORY] Sound proof booth and EEG recording [r=?ISO-8859-1?Q?=E9sum=E9?= ] From: Massimo Grassi <massimo.grassi@xxxxxxxx> Date: Fri, 7 Jun 2013 08:47:11 +0200 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Dear list members, below there is the list of all the replies I received. The original=20 question is at the top. I'm now writing another question to the list because, apparently, not=20 all people here are satisfied by the electrical shielding. Thanks to those who replied. m %%%%%%%%%%%%% Dear list members, we are about to buy a IAC soundproof booth and, because here many people=20 do EEG recordings, we were thinking to have the booth electrically=20 shielded. The booth will be used to run psychoacoustics, cognitive=20 science and neuroscience experiments. Here comes the problem. What is the best way to carry the EEG-signal=20 from the inside of the booth to the outside of the booth? So far we thought two possible solutions. 1. Place a panel on the booth's wall that has (inside and outside) the=20 specific plug of the signal cable that comes out of EEG amplifier. In=20 practice, we interrupt the signal cable at the booth's wall. 2. Make a hole on the booth's wall. The hole starts high in the inside=20 of the booth, runs downward inside the booth's wall and arrives low at=20 the outside of the booth. I this way the booth is acoustically safe=20 because the hole is not direct and the EEG-signal cable is not=20 interrupted, but it needs to be very long (wild guess about 6/8 meters). Some of my EEG colleagues are unhappy with both solutions because: 1. You interrupt the signal cable and this interruption could introduce=20 artefacts in the EEG-signal. 2. The cable is too long and this could introduce artefacts in the=20 EEG-signal. Is there anybody out there that had this same problem and that can=20 suggest me which is the best way to solve it? All the best, m %%%%%%%%%%%%% Classification: UNCLASSIFIED Caveats: NONE We are primarily an EEG lab, and recently built a new facility. Here are my thoughts: - While having a fantastic Faraday cage is theoretically great, in realit= y in can cause as many problems as it solves. For instance we have discover= ed that in many cases if you have ANY electrical devices inside, such as monitors, keyboards, whatever, it traps and bounces the power line noise much worse than just doing in a normal office room. The truth is that the latest generation of EEG systems, especially the wireless and active ones, are soooo much better SNR and less susceptible = to noise that this kind of thing just doesn't matter any more. - virtually all modern design EEG systems have the ADC on the head and ar= e broadcasting an already digitized signal to a receiver base, or at least connect to this base via fiber optic, and from there go to the recording = PC via USB. Point is... it's all USB digital going through the wall... so there shoul= d be no EEG signal attenuation due to that cable. Only concern will be if i= t is too long, the USB may need a small amplification (I believe the limit = is ~5-6 meters). The point of this is, you really only need a USB port on either side of t= he wall; possibly a parallel port for signal integration depending on the se= tup is laid out but again that is a digital signal. Now both of these points may be negated if your colleagues are using an extremely old analog system with wires, a remote ADC rack and such. But t= o be frank - given the falling costs and extreme difference in ease of use = and signal quality, it may be cheaper to buy a new EEG system than to get a fancy room. In our lab, we built in a massive patch panel with 20-something connector= s (USB, various audio, VGA, DVI, Ethernet, etc). If you go this route plan = for the latest and greatest! But we also left a "hole" behind the panels so w= e could run whatever cable we found necessary 5 years from now. Hope this is helpful, Dave ------------------------------------------ W. David Hairston, PhD. Real World Neuroimaging Translational Neuroscience Branch Human Research and Engineering Directorate, U.S. Army Research Laboratory (410) 278-5925 (office) william.d.hairston4.civ@xxxxxxxx * Note, new as of 7/2011 %%%%%%%%%%%%% Hi Massimo, I used to have an IAC booth that had a panel with several connectors (some BNC and some thick stereo jacks). The booth was already installed when I joined the lab, so I don't know if the panel came with the booth or if it was installed by Bioacoustics (the contractors that installed the booth). I assume that if it is factory installed it should be designed to not affect the soundproofing. Good luck with your experiments! Elena Grassi %%%%%%%%%%%%% Hi Massimo, > we are about to buy a IAC soundproof booth and, because here many peop= le > do EEG recordings, we were thinking to have the booth electrically > shielded. The booth will be used to run psychoacoustics, cognitive > science and neuroscience experiments. > > Here comes the problem. What is the best way to carry the EEG-signal > from the inside of the booth to the outside of the booth? The answer depends a little on what kind of EEG system you have. If you=20 have a Brain Products (most models) or a Biosemi EEG system they both=20 have fibre optic cables connecting the "head box" to the USB receiver,=20 which in turn is connected to a PC. These fibre optic cables are quite=20 long and do not introduce or pickup any EM interference. These systems=20 are even better as the headboxes are battery powered. If you have a Compumedics/Neuroscan system i.e. a Synamps, Synamps2 or=20 SynampsRT system then options are more limited as the headbox is=20 connected to the main system via a SCSI type copper cable. The lead on=20 these is a few metres in length. The main system has a mains plug and=20 does not run on batteries. You might be able to get away with shielded=20 power points and a shielded USB connection from the main system box to=20 the EEG recording PC but your mileage may vary on the maximum length of=20 the USB cable. You are going to have similar issues with EGI systems=20 (unless it is an MR compatible model), > So far we thought two possible solutions. > 1. Place a panel on the booth's wall that has (inside and outside) the > specific plug of the signal cable that comes out of EEG amplifier. In > practice, we interrupt the signal cable at the booth's wall. > 2. Make a hole on the booth's wall. The hole starts high in the inside > of the booth, runs downward inside the booth's wall and arrives low at > the outside of the booth. I this way the booth is acoustically safe > because the hole is not direct and the EEG-signal cable is not > interrupted, but it needs to be very long (wild guess about 6/8 meters= ). > > Some of my EEG colleagues are unhappy with both solutions because: > 1. You interrupt the signal cable and this interruption could introduc= e > artefacts in the EEG-signal. > 2. The cable is too long and this could introduce artefacts in the > EEG-signal. > > Is there anybody out there that had this same problem and that can > suggest me which is the best way to solve it? We have solved it by using a BrainProducts system. Thanks. Bryan. --=20 Bryan Paton PhD candidate Philosophy Program School of Philosophical, Historical and International Studies / School=20 of Psychology & Psychiatry 770 Blackburn Rd Building 220, Rm 141 Monash University Clayton, VIC, 3168 Australia +613 990 29790 Research Fellow EEG Lab Manager EEG & fMRI, TMS, TMS & EEG Liason Monash Biomedical Imaging 770 Blackburn Rd, Clayton VIC http://sites.google.com/site/bryanpaton %%%%%%%%%%%%% Massimo We do something a bit like 1) but requiring a much shorter cable. We=20 have a patch panel on the inside and outside of the booth, with a hole=20 at e.g. the bottom both on the inside and outside. We use a removable=20 piece of foam between the inner and outer walls of the booth as=20 insulation. The cable runs up one side of this foam piece on the inside=20 and then down it on the other (say 15 cm on each side). Seems to work fin= e Bob Dr. Bob Carlyon Programme Leader MRC Cognition & Brain Sciences Unit 15 Chaucer Rd. Cambridge CB2 7EF England Tel: +44 (0)1223 355294 Fax: +44 (0)1223 355294 www.mrc-cbu.cam.ac.uk MRC Centenary 1913-2013 | 100 years of life-changing discoveries %%%%%%%%%%%%% Dear Massimo We had IAC UK install an adapted double wall booth for EEG a few years=20 back. They added some additional screening through having no window in=20 the door and by electrically bonding all the parts with braiding. We also had DC lighting installed and the facility to kill the ac power=20 in the room. For getting EEG/ABR data out of the room had a tube installed through=20 the walls to an adjacent booth to take multicore cables. My=20 understanding is that thus tube acts as a waveguide and minimizes=20 interference. In practice we don't actually use this. Instead we have a Biosemi setup=20 with the amplifier/converter located inside the room. This is battery=20 powered and connected through the wall by USB cabling to the PC outside.=20 This kit is working really well for us, for ABR as well as cortical=20 responses. I am happy to get you more details if you are interested Dr Andrew Faulkner Head of Research Department of Speech Hearing and Phonetic Sciences UCL (University College London) Rm 314, Chandler House, 2 Wakefield St London WC1N 1PF tel 44 (0)20 7679 4075 (direct) Internal tel 24075 Fax: +44 (0)20 7679 4238 mailto:a.faulkner@xxxxxxxx http://www.ucl.ac.uk/psychlangsci/staff/shps-staff/a_faulkner %%%%%%%%%%%%% Dear, To spend cables through the wall of the booth, I use a U-shaped sandbox=20 with the two extremities of the U either side of the booth. You just have to remove the sand, pass the cable and refill with the sand= ! By the way, I would be interesting to know how you made your booth=20 electrically shielded (Faraday cage) ? Cheers, Nicolas. %%%%%%%%%%%%% Dear colleague, Being a retired elementary-particle physicist, I know nothing about EEG=20 signals. In our particle physics lab, however, we frequently transported=20 electrical signals over long distances. We used 50-ohm coaxial cables.=20 In the passage of walls, one can use connectors that have the correct=20 impedance (i.e., 50 ohms); the reflections at these points were found be=20 negligibly small (<10^-3 or so). Reinhart Frosch, Dr. phil. nat., CH-5200 Brugg. reinifrosch@xxxxxxxx . Sound proof booth and EEG recording [r=E9sum=E9.eml Subject: Sound proof booth and EEG recording [r=E9sum=E9] From: Massimo Grassi <massimo.grassi@xxxxxxxx> Date: 07/06/2013 08:42 To: AUDITORY@xxxxxxxx Dear list members, below the list of all replies I received. The original question is at=20 the top. I'm now writing another question to the list because, apparently, not=20 all people here are satisfied by the electrical shielding. All he best, m %%%%%%%%%%%%% Dear list members, we are about to buy a IAC soundproof booth and, because here many people=20 do EEG recordings, we were thinking to have the booth electrically=20 shielded. The booth will be used to run psychoacoustics, cognitive=20 science and neuroscience experiments. Here comes the problem. What is the best way to carry the EEG-signal=20 from the inside of the booth to the outside of the booth? So far we thought two possible solutions. 1. Place a panel on the booth's wall that has (inside and outside) the=20 specific plug of the signal cable that comes out of EEG amplifier. In=20 practice, we interrupt the signal cable at the booth's wall. 2. Make a hole on the booth's wall. The hole starts high in the inside=20 of the booth, runs downward inside the booth's wall and arrives low at=20 the outside of the booth. I this way the booth is acoustically safe=20 because the hole is not direct and the EEG-signal cable is not=20 interrupted, but it needs to be very long (wild guess about 6/8 meters). Some of my EEG colleagues are unhappy with both solutions because: 1. You interrupt the signal cable and this interruption could introduce=20 artefacts in the EEG-signal. 2. The cable is too long and this could introduce artefacts in the=20 EEG-signal. Is there anybody out there that had this same problem and that can=20 suggest me which is the best way to solve it? All the best, m %%%%%%%%%%%%% Classification: UNCLASSIFIED Caveats: NONE We are primarily an EEG lab, and recently built a new facility. Here are my thoughts: - While having a fantastic Faraday cage is theoretically great, in realit= y in can cause as many problems as it solves. For instance we have discover= ed that in many cases if you have ANY electrical devices inside, such as monitors, keyboards, whatever, it traps and bounces the power line noise much worse than just doing in a normal office room. The truth is that the latest generation of EEG systems, especially the wireless and active ones, are soooo much better SNR and less susceptible = to noise that this kind of thing just doesn't matter any more. - virtually all modern design EEG systems have the ADC on the head and ar= e broadcasting an already digitized signal to a receiver base, or at least connect to this base via fiber optic, and from there go to the recording = PC via USB. Point is... it's all USB digital going through the wall... so there shoul= d be no EEG signal attenuation due to that cable. Only concern will be if i= t is too long, the USB may need a small amplification (I believe the limit = is ~5-6 meters). The point of this is, you really only need a USB port on either side of t= he wall; possibly a parallel port for signal integration depending on the se= tup is laid out but again that is a digital signal. Now both of these points may be negated if your colleagues are using an extremely old analog system with wires, a remote ADC rack and such. But t= o be frank - given the falling costs and extreme difference in ease of use = and signal quality, it may be cheaper to buy a new EEG system than to get a fancy room. In our lab, we built in a massive patch panel with 20-something connector= s (USB, various audio, VGA, DVI, Ethernet, etc). If you go this route plan = for the latest and greatest! But we also left a "hole" behind the panels so w= e could run whatever cable we found necessary 5 years from now. Hope this is helpful, Dave ------------------------------------------ W. David Hairston, PhD. Real World Neuroimaging Translational Neuroscience Branch Human Research and Engineering Directorate, U.S. Army Research Laboratory (410) 278-5925 (office) william.d.hairston4.civ@xxxxxxxx * Note, new as of 7/2011 %%%%%%%%%%%%% Hi Massimo, I used to have an IAC booth that had a panel with several connectors (some BNC and some thick stereo jacks). The booth was already installed when I joined the lab, so I don't know if the panel came with the booth or if it was installed by Bioacoustics (the contractors that installed the booth). I assume that if it is factory installed it should be designed to not affect the soundproofing. Good luck with your experiments! Elena Grassi %%%%%%%%%%%%% Hi Massimo, > we are about to buy a IAC soundproof booth and, because here many peop= le > do EEG recordings, we were thinking to have the booth electrically > shielded. The booth will be used to run psychoacoustics, cognitive > science and neuroscience experiments. > > Here comes the problem. What is the best way to carry the EEG-signal > from the inside of the booth to the outside of the booth? The answer depends a little on what kind of EEG system you have. If you=20 have a Brain Products (most models) or a Biosemi EEG system they both=20 have fibre optic cables connecting the "head box" to the USB receiver,=20 which in turn is connected to a PC. These fibre optic cables are quite=20 long and do not introduce or pickup any EM interference. These systems=20 are even better as the headboxes are battery powered. If you have a Compumedics/Neuroscan system i.e. a Synamps, Synamps2 or=20 SynampsRT system then options are more limited as the headbox is=20 connected to the main system via a SCSI type copper cable. The lead on=20 these is a few metres in length. The main system has a mains plug and=20 does not run on batteries. You might be able to get away with shielded=20 power points and a shielded USB connection from the main system box to=20 the EEG recording PC but your mileage may vary on the maximum length of=20 the USB cable. You are going to have similar issues with EGI systems=20 (unless it is an MR compatible model), > So far we thought two possible solutions. > 1. Place a panel on the booth's wall that has (inside and outside) the > specific plug of the signal cable that comes out of EEG amplifier. In > practice, we interrupt the signal cable at the booth's wall. > 2. Make a hole on the booth's wall. The hole starts high in the inside > of the booth, runs downward inside the booth's wall and arrives low at > the outside of the booth. I this way the booth is acoustically safe > because the hole is not direct and the EEG-signal cable is not > interrupted, but it needs to be very long (wild guess about 6/8 meters= ). > > Some of my EEG colleagues are unhappy with both solutions because: > 1. You interrupt the signal cable and this interruption could introduc= e > artefacts in the EEG-signal. > 2. The cable is too long and this could introduce artefacts in the > EEG-signal. > > Is there anybody out there that had this same problem and that can > suggest me which is the best way to solve it? We have solved it by using a BrainProducts system. Thanks. Bryan. --=20 Bryan Paton PhD candidate Philosophy Program School of Philosophical, Historical and International Studies / School=20 of Psychology & Psychiatry 770 Blackburn Rd Building 220, Rm 141 Monash University Clayton, VIC, 3168 Australia +613 990 29790 Research Fellow EEG Lab Manager EEG & fMRI, TMS, TMS & EEG Liason Monash Biomedical Imaging 770 Blackburn Rd, Clayton VIC http://sites.google.com/site/bryanpaton %%%%%%%%%%%%% Massimo We do something a bit like 1) but requiring a much shorter cable. We=20 have a patch panel on the inside and outside of the booth, with a hole=20 at e.g. the bottom both on the inside and outside. We use a removable=20 piece of foam between the inner and outer walls of the booth as=20 insulation. The cable runs up one side of this foam piece on the inside=20 and then down it on the other (say 15 cm on each side). Seems to work fin= e Bob Dr. Bob Carlyon Programme Leader MRC Cognition & Brain Sciences Unit 15 Chaucer Rd. Cambridge CB2 7EF England Tel: +44 (0)1223 355294 Fax: +44 (0)1223 355294 www.mrc-cbu.cam.ac.uk MRC Centenary 1913-2013 | 100 years of life-changing discoveries %%%%%%%%%%%%% Dear Massimo We had IAC UK install an adapted double wall booth for EEG a few years=20 back. They added some additional screening through having no window in=20 the door and by electrically bonding all the parts with braiding. We also had DC lighting installed and the facility to kill the ac power=20 in the room. For getting EEG/ABR data out of the room had a tube installed through=20 the walls to an adjacent booth to take multicore cables. My=20 understanding is that thus tube acts as a waveguide and minimizes=20 interference. In practice we don't actually use this. Instead we have a Biosemi setup=20 with the amplifier/converter located inside the room. This is battery=20 powered and connected through the wall by USB cabling to the PC outside.=20 This kit is working really well for us, for ABR as well as cortical=20 responses. I am happy to get you more details if you are interested Dr Andrew Faulkner Head of Research Department of Speech Hearing and Phonetic Sciences UCL (University College London) Rm 314, Chandler House, 2 Wakefield St London WC1N 1PF tel 44 (0)20 7679 4075 (direct) Internal tel 24075 Fax: +44 (0)20 7679 4238 mailto:a.faulkner@xxxxxxxx http://www.ucl.ac.uk/psychlangsci/staff/shps-staff/a_faulkner %%%%%%%%%%%%% Dear, To spend cables through the wall of the booth, I use a U-shaped sandbox=20 with the two extremities of the U either side of the booth. You just have to remove the sand, pass the cable and refill with the sand= ! By the way, I would be interesting to know how you made your booth=20 electrically shielded (Faraday cage) ? Cheers, Nicolas. %%%%%%%%%%%%% Dear colleague, Being a retired elementary-particle physicist, I know nothing about EEG=20 signals. In our particle physics lab, however, we frequently transported=20 electrical signals over long distances. We used 50-ohm coaxial cables.=20 In the passage of walls, one can use connectors that have the correct=20 impedance (i.e., 50 ohms); the reflections at these points were found be=20 negligibly small (<10^-3 or so). Reinhart Frosch, Dr. phil. nat., CH-5200 Brugg. reinifrosch@xxxxxxxx .