Fostex T50RP Incremental Mods and Measurements (FIMM) Table of Contents 1. Introduction 2. DIY Measurement Kit 3. No Solder Phantom Power Supply and Mic 4. Making Incremental Measurements 5. REW .mdat files, ARTA Setup Pictorial, and Videos stored at Google Drive and Docs 6. Audio Measurement Chain 7. Begin Incremental Mods and Measurements 8. Temporary Bass Ports 9. Additional Requested Pictures and Graphs 10. DBV 1 11. DBV 2 12. My LCD2 Measurements 13. All Stock T50RP T40RP T20RP with Triflange and Foam Tip Mounted Mics 14. About Measurements and Tuning 15. Some Additional Photos of Mods and Kits 16. Preparing Rolled Cotton For Effective Damping 17. Pad Rolling 18. Shure 840 Pad Modification and Measurements 19. Implementing Tutorials and Pictorials 20. Simplified and Consolidated Tutorial for DBV 3 21. Simplified and Consolidated Pictorial for DBV 3 22. Rock Wool Mod - Improved 23. nick n Make-up Remover Memory Foam Mod 24. Paxmate Lattice Mod with Cotton or Grodan Rock Wool 25. Balsa Wood Mod with Paxmate and Rock Wool 26. Tuning Rules of Thumb 27. Repairing Stripped Cup Threads 28. Better Modified Bass Ports 29. Naked Driver Mod - Improved 30. T50RP Wave Guides AKA Phase Plugs DIY using basswood or balsa wood 31. T50RP Wave Guides - 3D Printed by SeEnCreaTive 32. T50RP Incrementally Mass Loading the Baffles with Dynamat Xtreme, Paxmate Plus, and Tungsten Putty 33. Crossfeed Filters 34. DIY Mods and Measurements Acknowledgements Introduction You bought a set of Fostex T50RP planar magnetic headphones to see what all the modding talk is about. If you are a beginner like I was when I started down the modification path two years ago, you probably don't know where to start. I initially tried some of the mods suggested in the T50RP modding thread with mixed results before branching out and trying different materials and configurations of my own. A year later in July 2012, I decided to evaluate the damping effects of various materials - individually and in combination. I made incremental mods and measurements using a "virgin" set of current production T50RP's. The set I used has the non-textured, translucent white driver dampening "paper" and the darker color - smoother finished metal hangers. I measured each mod using Room Equalization Wizard (REW), my MacBook Pro sound card, and a basic $50.00 DIY measurement kit comprised of a Phantom Power Supply and a Panasonic WM-61A Omnidirectional Electret microphone stuck in my ear. FIMM graphs should be compared and interpreted relative to one another, only. FIMM measurements and graphs cannot be directly compared to others' measurements. The microphone used for incremental measurements failed after I completed DBV #2. I built other microphones and a better phantom power supply designed by 'solderdude.' Measurements with this new kit cannot be reliably compared to FIMM measurements. All information, photographs, and measurement graphs contained within this document are owned by me and represent my intellectual property. I have made this document available for anyone to use for DIY modification of their personal headphones. Use of any and all information, photographs, and measurement graphs in this document for publication, advertising, and profit is prohibited without my written consent Use of the tutorials, pictorials, guides, measurement graphs, and all information within this document are provided for DIY modification of your headphones. Use this document at your own risk. Please understand that your results and opinions may differ from mine due to variations in: materials used, implementation of mod components, audio equipment chains, music file type and resolution, hearing acuity, personal preferences, and Positive and Negative confirmatory bias. DIY Measurement Kit A pictorial guide for making your own DIY measurement kit, REW links, REW Setup Pictorial, and more are located at the following link: http://www.head-fi.org/t/452404/just-listened-to-some-fostex-t50rps-today-wow/8025#post_8354423 ***Improved Phantom Power Supply by Solderdude - Recommended*** More information is available throughout Solderdude's thread...Thanks, Frans! ***Panasonic WM-61A: Triflange-Mounted Mic In Your Ear Method vs DIY Dummy Head Method*** Frans ran some experiments comparing Panasonic WM-61A mounted on a triflange IEM tip (sealed ear canal method) and WM-61-A mounted in a wooden dummy head. His results are interesting and his report is a Must Read for anyone using these methods. Frans' measurements of many headphones may be found HERE. Frans' ('solderdude') Improved Phantom Power Supply (Mono) Frans designed an improved Phantom Power Supply for use with the Panasonic WM-61A omni-directional electret microphone (or similar). Note the WM-61A was discontinued in late 2013. I bought 50 authentic WM-61A microphones from an eBay seller in Japan (pestman2012). Beware of many counterfeit WM-61A's from China, Hong Kong, and elsewhere. Some available from another eBay seller in Japan (bzf202022012) as of July 2014 look authentic but I cannot tell for certain without looking for the etched model number on the side of each one, under magnification. If anyone needs a couple at cost ($3.00), PM me. Here's Frans' Phantom Power Supply schematic (Mono): The upper schematic is for usage with non-polar capacitors. The bottom one is for usage with much cheaper electrolytic caps. Be aware of the polarity of the electrolytic capacitors, if used. For the jack plug in the schematic the output is connected to the R channel (ring) but you can also connect it to the tip (Left channel) OR both channels (L + R). Some mic inputs have the R (ring) and ground connected. In that case the signal must go to the tip connection and the ground is the same. Read more: http://diyah.boards.net/thread/361/?page=2#ixzz2pXvWvBrv Phantom Notes: Februray 2015 1. The connectors shown in the schematic diagram show how to wire the most common connectors. You should use only the connector type you need, so not both types of connectors, shown. Substitute your preferred connectors and jacks. I chose 3.5 mm TRS jacks. 2. 6k8 = 6.8k Ohm Resistor (just a different way of notation) 3. This design is for testing one channel at a time. REW requires Stereo jacks and plugs even when measuring in mono mode. 4. Using a 10.0 uF capacitor yields more extended bass FR than 4.7 uF capacitor. Microphone Notes July 2015 I searched previous Japanese sellers of authentic Panasonic WM-61A microphone capsules but none are currently available. Steer clear of fakes from China, Hong Kong, and Taiwan. I bought some replacements on ebay but have not compared them to authentic Panasonic WM-61A. On ebay, search for seller mstrong1 and item Panasonic WM-61A Replacement Microphones currently $2.50 each. Soldering these tiny mics is challenging. The Negative solder pad is connected to the microphone casing with a copper trace and the Positive solder pad is isolated from the capsule casing. Step by Step Instructions Using the Re-flow Method Mic End: Place the mic in a Panavise. Strip both ends of a 4' of Mogami W2490. I make the Red Positive and the White Negative. Pre-tin both wires at both ends. Clean and pre-tin your iron. Cut the ends of the Red and White Mogami wires to 1/16". Pre-tin the solder pads. Apply a bit of flux on the tinned wires and the the tinned solder pads. Place the pre-tinned and fluxed wire flat against the solder pad. Touch the tinned and cleaned iron onto the wire and press down so the wire remains in place against the solder pad. Get in and out fast...only ~ 2 seconds. If it does not work, let the mic cool while you re-clean your iron, pre-tin the solder pad and wire if needed, and re-flux. When it re-flows, remove the iron and keep the wire in place until the joint solidifies. Repeat for the other solder pad. Test continuity with a DMM. Fill the entire circuit board and the soldered connections with a drop or two of super glue or J&B Weld...But, wait until you have successfully soldered the other ends of the Mogami to the TRS plug and confirmed continuity and no shorts. TRS End: Cut pieces of 3:1 heat shrink for the TRS plug and slide onto the Mogami cable. Slide the TRS plastic shield onto the Mogami cable. Slide the TRS jacket onto the Mogami cable. Identify the Positive tab on the TRS = usually the shorter of the two is Positive...Confirm with your DMM. Flux and pre-tin the TRS Positive tab and the Sleeve tab (Negative). Pre-tin the wires and cut to ~ 1/2" Tin and clean your iron. Thread the wires into the TRS tab holes and make a firm mechanical connection by twisting the wires. If there are no holes in the tabs, you can drill holes with a 1/16" drill bit or hold the wires in place as you solder. Check for continuity to insure you have not shorted the Positive and Negative wires...a single tiny strand can short circuit so use a magnifying glass or magnifying headset to visually inspect your work. Clamp the wires onto the TRS plug by bending the tabs over and onto the wires making a strain relief. Slide the TRS plastic shield over the soldered connections. Slide the heat shrink in place as far as it will go. Slide the TRS jacket in place and screw it onto the TRS plug. The heat shrink should fill the gap at the wire entry hole of the TRS jacket and extend about an inch outside the jacket. Use a heat gun to shrink the shrink wrap. Test: Connect your mic to your measurement kit. Open your measurement software and test the mic by talking or blowing on the mic. The software dB meters should indicate whether or not you have a working mic. Finish up: Apply super glue on the mic circuit board and solder tabs. Spray with super glue accelerator for instant curing or wait until the super glue has fully cured Here's what I use from markertek.com 2490Mogami W2490 Ultraflexible Miniature Microphone Cable - Gray PER FOOT52$0.22$11.44Shipped NYS-231BGRean NYS231BG 3.5MM TRS Plug Black/Gold6$1.39$8.34Shipped SHT116BK-4Heat Shrink Tubing 1/16inch Black 4 Foot1$0.88$0.88Shipped Mono Phantom Power Supply Back Right to Left: Red Positive Battery Lead > 6.8k R >2.2k R > Positive 100 uF Cap 6.8k R > 2.2k R > Positive 10 uF Cap > 100k R and Red wire to Left side Mic IN Jack (Ring tab) Negative 100 uF Cap > Blue wire > 100k R Negative 10 uF Cap >100k R 100k R > Both Blue wires to Negative tabs on Both Jacks; Negative Black Battery Lead; Green ground to metal tin Back View Closed cell foam glued to under surface to insulate the solder connections from the metal tin. Front Left to Right: Red Positive Battery Lead to 6.8k R > 2.2k R > Positive 100 uF Cap > Negative 100 uF Cap > Blue wire Side View Negative 100 uF Cap > Blue wire > 100k R > 2 Blue Wires > Negative Jack tabs; Black Negative Battery Lead; Green to ground Top View Frans' aka 'solderdude's' Phantom Power Supply I found using a 10.0 uF cap delivers better bass measurements. Fran's Dual / Stereo Phantom Power Supply February 2015 Two examples of the same circuit: Large Form Factor Notes: 1. Panasonic WM61-A microphone capsules Positive terminal must be wired to either the Tip (Left Channel) or the Ring (Right Channel) TRS tabs / lugs. For REW and ARTA, use the Tip (Left Channel). 2. For most measurements, you don't need a dual Phantom Power Supply. Simply place the mic in your preferred ear or onto your Dummy Head Jig, take a measurement of the Left Cup, then rotate the headphone and measure the Right Channel. 3. For Mono / single channel measurements of headphones with angled pads, rotate the pads 180 degrees for accurate results. 4. Your ear canals are not the same size. The mics may insert at slightly different depths, angles, and degrees of seal in Left vs Right ears. This will likely result in what appears to be channel imbalance but is actually measurement error. You will have to compensate for this type of error. Read about compensation in REW and ARTA user manuals or "Google it." No Solder Phantom Power Supply Feb. 2015 You don't have to know how to solder to make a Phantom Power Supply and Mic kit! Simply remove 3/4" of insulation from your hook-up wires, twist the wires and "legs" of the caps and resistors together, tightly. Compress with a mini-screwdriver or needle-nose pliers and secure in place with J&B Weld epoxy. Do the same for the TRS jacks and you're done, mount in a metal tin, and you're ready to measure using free software like REW and the free trial version of ARTA. Mics: Score the mic solder tabs with a mini-file to make a groove for the hook-up wires. Place the tightly twisted hook-up wire in a groove and secure with tape. Apply some electrically conductive paint in 2 or 3 thin coats, letting it dry between coats. Dab a bit of epoxy onto the wire and fill the groove. Repeat for the other solder tab. No solder was used making the Phantom Power Supply and the mic. All connections were made mechanically, only. J&B Weld holds everything in place and insulates the undersurface of the bread board so there's no shorting from the twisted wires to the tin. This kit was actually more difficult to build than using solder. The purpose was to determine if it's possible so anyone can build a kit, even without soldering skills. It works just as well as soldered kits. Magnification is necessary to make sure there are no shorts when making the mic and TRS connections. A single stray strand of wire can short at the mic and at the TRS. CABLE CONNECTIONS Blue 3.5mm male Stereo TRS to 3.5mm male Stereo plugs into Headphone OUT and Mic IN for the Calibration Loop. Alternatively, you can place the Phantom Power Supply into the chain by using Two of these cables. White 3.5mm Stereo TRS cable plugs into my Mac's MIC In jack. The other end, also terminated with a 3.5 mm Stereo TRS plug goes into the Phantom Power Supply's Line OUT jack. Beneath my Mac's Mic IN jack with the white cable, you see an optical cable plugged into my Mac's Headphone Out jack. The other end connects to my Dacmini's Optical IN. The headphone undergoing measurement is connected to my Dacmini's headphone jack. These two photos show the rest of the connections: White cable from Mac Line IN to Phantom Power Supply Line OUT. Mic mounted on Etymotic triflange IEM ear tip terminated with a Female RCA plug connects to either of two Male RCA plugs. Dual Male RCA Y-Splitter to 3.5 mm Stereo TRS plug goes in the Phantom Power Supply's Line IN. Place the mic in your ear and be sure you position it the same way each time you measure = Same depth, Same angle, Same ear. Place the headphones on your head and make sure you use your normal position and with same clamping force each time. Use an earplug in your non-measuring ear to protect your hearing. Turn down the volume, Select 'Measure' and then Select 'Check Levels.' Increase volume until you reach 'Check Level' = -20 dB Select 'Cancel' Select 'Measure' and Select 'Start Measuring' See Link to Tutorials with Screen Shots (Just Below) for details about configuring, calibrating, and setting-up and using REW. There are more photos of making your microphone near the bottom of this very long post. Be patient. We're almost there... I encourage everyone to consider building and using a measurement kit. I find it indispensable for L-R Channel balancing and tuning. It's also interesting, easy to use, fast (6 seconds per measurement), and fun. MAKING INCREMENTAL MEASUREMENTS I mounted the mic in an Etymotic triflange ear tip using hot glue. Next, I applied a ring of hot glue around the mic sitting on its perch at the IEM insertion hole. When making these measurements over two consecutive weekends, I made sure to use the same methodology. I placed the mic in my ear at the same angle and depth on both measurement days. I did not remove the mic until all measurements were completed, each day. I SPL-matched the sweep level for each measurement. Various pads X mod(s) result in wide variability in sensitivity. Matching the sweep levels may not be necessary but I did so to control this variable. I placed the headphones on my head based on my usual, most comfortable position whenever I use headphones. Considering the number of measurements and variables assessed, I made only 1 measurement for each. The baffles were secured to the cups with masking tape to avoid stripping the cup threads from multiple modding cycles done one at a time. I squeezed the baffle to the cup while taping and insured that all gaps and crevices were tightly sealed. Consider the data FWIW or a "snapshot" of each mod. The small, sharp up/down "tics" in the SPL FR graphs and the very thin ridges in most of the waterfall plots are the result of "cable noise" from electromagnetic interference according to the REW Moderator. The FR graphs don't tell us anything about the speed or decay of each mod. I included Waterfall Plots to show the speed and decay on the 'z' axis, back to front. Anyone can download and use REW for free but please contribute (any amount) to support the site. You can use, view, and manipulate .mdat files without having to actually make any measurements of your own. Here's the link: http://www.hometheatershack.com/roomeq/ The default graph format is SPL FR. Tabs across the top of the measurement window allow you to 'Generate' waterfall plots and spectrograms. You must adjust the SPL FR display to 'Zero' before Generating waterfalls and spectrograms. To do this, click the 'gear' icon at the top right of the measurement window. Type an offset value in the offset window - I typically use -155, then click 'Add to Data.' Go to the left side, vertical slider to pull the adjusted SPL FR graph down into the display window. Now, you can generate waterfalls and spectrograms along with decay and several other options, if interested. ***Select 'Room Equalization Wizard (REW) Set-up Guide' (below) for a Google Doc that explains more about how to setup and use REW. I included some useful links and screen shots for clarity.*** You Can Learn How to Use REW Before You Begin Making Your Own Measurements I uploaded the REW raw data .mdat files to Google Docs for all incremental measurements I made and listed in the links, below. First, download and install REW and then download and save the .mdat files from Google Docs into your computer's 'Downloads' file. Next, open REW and click on 'Open', go to your 'Download' files, double click the desired set of .mdat files, and the data files will load into REW. Within REW's measurement window, and after you've 'Opened' a .mdat data file, you can delete all but the particular graphs you want to overlay with one another. The individual data files are listed on the left side of the measurement window. Delete each file you want to remove by clicking the 'red X' to the right of one. This removes the file(s) from the list but does not permanently delete the file(s) stored in 'Downloads.' Next, click 'All SPL', located at the top tool bar of the measurement window, to display your chosen graphs as an overlay. You can change the resolution by clicking the '-' or '+' tabs at the top left of the SPL graph; i.e. 5 db or 10 dB SPL intervals. You can save this specific group of graphs by clicking 'Save All' at the top left of the window and type in a Group Name. When you're done comparing this set of measurements, close this file, after naming and saving it, by clicking the 'Remove All' tab. Re-open the complete .mdat file to repeat the process for a different group of comparisons. For example, you can delete all but the 3 graphs for "Stock Left Acoustipack Lite, Newplast, and type of pad (840, Stock, and FA-003 pads)" for comparing and overlaying these 3 graphs. Do the same for any other combination of incremental measurements from any of the .mdat files I uploaded to Google Docs. Incremental Mods and Measurements, REW .mdat files, ARTA Setup Guuide, and Videos stored in Google Docs: 1. Room Equalization Wizard (REW) Set-up Guide 2. Main data set 1 .mdat data files for Incremental Mods and Measurements 3. Main data set 2 .mdat data files for Incremental Mods and Measurements 4. DBV #1 and #2 .mdat files: https://docs.google.com/open?id=0B5ZWXtWdNv9UYTBUZHRFTXZZSzQ 5. Stock T50RP, T40RP mk2, T20RP mk2 measurements with Etymotic Foam and Triflange mounted microphones .mdat files: https://docs.google.com/open?id=0B5ZWXtWdNv9URmRSLW5mN0Vzblk 6. DBV #2 with Taped on FA-003 Pads, T50RP Pads, and Inner Tube Modded FA-003 Pads .mdat files: https://docs.google.com/open?id=0B5ZWXtWdNv9UWlcyeXVFbU1XblE 7. Disassembling Fostex T50RP/T40RP mkII/T20RP mkII For Repairs and Driver Modification - If this video does not open, try Right Clicking on the File Name and 'Open With Google Drive Viewer.' Also available via dropbox. 8. "Radical Russian Roulette" Driver Modification Video - If this video does not open, try Right Clicking on the File Name and 'Open With Google Drive Viewer.' Also available via dropbox. 9. ARTA Setup Guide for Beginners uploaded to Google Drive January 2015 T50RP Incremental Mods and Measurements Audio Measurement Chain Calibrated MacBook Pro Soundcard > REW Generated Sweep > Glass Toslink > Dacmini with 1 Ohm Output Impedance Mod > Headphones > Calibrated Panasonic WM-61A Microphone > Calibrated Phantom Power Supply > MacBook Pro > REW Analysis General Interpretive Guidelines for REW Measurement Graphs 1. Frequency Response Graph (FR): Zero dB horizontal x-axis is the baseline. The frequencies in Hertz (Hz) are shown at the bottom in logrithmic format. The vertical y-axis is Sound Pressure Level (SPL) in decibels (dB) which indicates how "loud" the headphones measure. Positive numbers indicate louder than baseline. Negative numbers indicate less loudness than baseline. +/- 2 dB above or below the baseline is acceptable and you probably would not be able to hear a significant difference. An ideal FR "curve" would actually be a flat line at zero dB extending all the way across the graph from sub-bass on the far Left to high treble on the far Right. FR graphs tell us nothing about resonances or ringing, speed of decay, impulse response, phase, or how the headphones will sound. You don't need to worry about any of these for now. Just understand that resonances, ringing, and slow decay speed are "Bad".... and, flat FR and fast decay are "Good." 2. Waterfall Graph: This is a 3D graph with 3 axes - SPL in dB on the vertical y-axis, Frequencies in Hz on the horizontal x-axis, and Decay Time on the Back to Front z-axis. Ideally, you want the x-axis to be as flat and uniform as possible across the top from left to right which indicates an even, or "flat" FR. The waterfall from the back of the z-axis extends forward and indicates the decay speed and whether or not there is ringing at particular frequencies. Generally, you're more likely to perceive a spike than a dip. A "suckout" is a wider (x-axis) range of frequencies that is more easily "heard." 3. Spectrogram: This graph shows speed of decay, ringing/resonances, dips, spikes, and suckouts. The vertical y-axis indicates speed of decay in milliseconds and the horizontal x-axis marks frequencies from sub-bass to treble (Left to Right). The Color Scale on the right side of the graph indicates SPL from 0 = Red to - 40 = Blue. Ideally, you want to see a wide, uniform beam of red with thin layers of yellow, green, and blue from far Left to far Right. Green and Blue "Flames" indicate low level ringing that may be difficult to hear. Yellow and Red Flames are more likely heard. Upward "Bulges" indicate humps. "Squeezed" areas indicate dips. "Pinched off" areas are suck-outs that are more easily heard. Use all three graphs to better understand your headphones' performance and make more accurate predictions about how they might sound. Start by looking at the "All Stock T50RP" FR and Waterfall graphs. Notice the big hump in the middle and the slopes to either side, especially on the left side. This indicates a mid-centric headphone with weak bass and weak treble that "rolls off." What the graphs do not show, however, is the resonance and standing waves heard from Stock T50RP's and described throughout the main T50RP mod forum. Begin Incremental Mods and Measurements A. Fostex T50RP - All Stock Left Side: Current production with smooth finished metal hangers and non-textured, translucent white driver dampener 1. All Stock T50RP 2. Stock with sealed cup vents 3. Stock with sealed baffle port 4. Stock with sealed cup vents and sealed baffle port B. Masking tape temporarily seals baffle to cup without risking stripping the cup threads. Shure 840 pads (Left) and FA-003 pads (Right-micmacmo's inner tube mod). 5. Stock with Shure 840 pads 6. Stock with Shure 840 pads and sealed cup vents 7. Stock with Shure 840 pads, sealed cup vents, and sealed baffle port 8. Stock with Shure 840 pads and sealed baffle port C. Temporary Bass Port using electrical tape or masking tape on the outside of the cup vents. Once the mod is completed, the bass port is moved to the inside of the cup unless you prefer the flexibility of re-tuning, on the fly. Masking tape makes the job easier because you first apply a piece that covers all 4 cup vents and then use an X-acto knife to cut the precise size bass port you want. This masking tape bass port is 3x1 mm. To prevent the tape from separating at the corners (Not Shown in the photo, above), use an X-acto knife to remove the excess tape from where it overlaps onto the back of the cups and down the side walls flush with the cup vents. Once removed, smooth out and compress the tape flat onto the four cup vent slots. Use an X-acto knife to cut an opening over the center of one of the vent slots to make your modified bass port. Enlarge by 1 mm increments. If it's too wide, bass bloat will return. In this case, decrease the width of the bass port in 1 mm increments by placing a small piece of masking tape over part of the bass port already opened. When you have determined the size of the bass port needed for your mod configuration, you can make a permanent one by duplicating and placing it over the cup vents on the inside. Cut a piece of masking tape to cover all the stock black cup felt overlaying the cup vents. Place the tape over the vent felt on the inside of the cup. Use shirt pins pushed through from the outside to mark the limits of the bass port width on the inside. Use the "pin markers" to trace a rectangular opening on the masking tape. Remove the tape but leave the pins in place. Cut out the rectangle from the masking tape, re-apply the tape onto the vent felt on the inside by using the pins as your guide, and remove the pins. Glue all the way around the masking tape so it will remain in place and not "leak" around the edges. The size of your bass ports from left to right may need to be different to balance the FR. In some cases, you may have, for example, a 3x1 mm bass port on one side and no bass port on the other side. D. 9. Stock with Shure 840 pads and 3 mm bass port Grodan rock wool: 10x 60x70 mm with extra "fluff" around the rim. Thanks, JoelPearce and micmacmo. 10. Stock with Grodan Rock Wool and Shure 840 Pads 11. Stock with Grodan Rock Wool and Stock Pads 12. Stock with Grodan Rock Wool and FA-003 Pads Note: micmacmo's Inner Tube Modded FA-003 Pads were used throughout these measurements. E. "Unobtanium" Rite Aid Natural Absorbent Cotton - approximately 15 cm wide and 4 cm thick out of the box and easily separated to the desired thickness. Other types of cotton may work but will likely require altering the amount and thickness used. 13. Stock with Cotton and Shure 840 Pads 14. Stock with Cotton and Stock Pads 15. Stock with Cotton and FA-003 Pads F. 50x60x70 mm Johns Manville fiberglass - uncompressed G. 50x60x70 mm Johns Manville fiberglass compressed into cup with extra "fluff" around the rim. Note the rubber shock absorber caps showing through the fiberglass. 16. Stock with Fiberglass and Shure 840 Pads 17. Stock with Fiberglass and Stock Pads 18. Stock with Fiberglass and FA-003 Pads H. 1.5x35x35 mm Creatology Stiffened Craft Felt from Michaels' secured with strips of Transpore tape. A better method uses 1.5x37x45 mm Creatology Stiffened Craft Felt secured by double sided tape strips cut to fit the outer edges of the driver grid. Thanks nick n. 19. Stock with 1.5x35x35 mm Stiffened Craft Felt over the driver and Shure 840 Pads 20. Stock with 1.5x35x35 mm Stiffened Craft Felt over the driver and Stock Pads 21. Stock with 1.5x35x35 mm Stiffened Craft Felt over driver and FA-003 Pads I. 12x35x35 mm open cell foam over the driver secured with Transpore tape. 22. Stock with Open Cell Foam over driver and Shure 840 Pads 23. Stock with Open Cell Foam over driver and Stock Pads 24. Stock with Open Cell Foam over driver and FA-003 Pads J. 4x35x35 mm 100% Wool Felt from Hobby Lobby, over the driver 25. Stock with 4x35x35 mm Hobby Lobby 100% Wool Felt over driver and Shure 840 Pads 26. Stock with 4x35x35 mm Hobby Lobby 100% Wool Felt over driver and Stock Pads 27. Stock with 4x35x35 mm Hobby Lobby 100% Wool Felt over driver and FA-003 Pads K. Acoustipack Lite and Self-Adhesive Felt in the cup floor. The Acoustipack is in the left and right "floor wells" and the self-adhesive felt is at the top and bottom of the center area, above and below the headband hanger compartment. 28. Stock with Acoustipack Lite and Felt in Cup Floors with Shure 840 Pads 29. Stock with Acoustipack Lite and Felt in Cup Floors with Stock Pads 30. Stock with Acoustipack Lite and Felt in Cup Floors with FA-003 Pads L1. 20 grams of Newplast is less than 1 oz. 10 grams per side. Acoustipack Lite and self-adhesive felt in the cup. Newplast "Flush Mass Loaded" in the baffle compartments. A digital scale is not required. I used one to demonstrate just how little Newplast or plasticine is needed 31. Stock with Acoustipack Lite and Felt in Cup Floor, Newplast, and Shure 840 Pads 32. Stock with Acoustipack Lite and Felt in Cup Floor, Newplast, and Stock Pads 33a. Stock with Acoustipack Lite and Felt in Cup Floor, Newplast, and FA-003 Pads L2. This "Naked Driver" is associated with Graphs 33b, 33c, and 33d, Only. ALL preceding and subsequent graphs are based on modifications with the stock white driver dampening paper intact. "Naked" Driver has had its stock white 'paper' removed, Acoustipack Lite and Felt in Cup Floors, and Newplast Flush Mass Loaded in the baffles. I do not recommend removing the stock white driver dampening "paper" from the back of the drivers. In my experience, this offers no benefits over keeping the stock white dampener intact. 33b. Naked Driver, Acoustipack Lite and Felt in Cup Floor, Newplast, Shure 840 Pads 33c. Naked Driver, Acoustipack Lite and Felt in Cup Floor, Newplast, and Stock Pads 33d. Naked Driver, Acoustipack Lite and Felt in Cup Floor, Newplast, FA-003 Pads M. 1.5x35x35 mm Creatology Stiffened Craft Felt has been added to the back of the driver, directly over the stock white driver dampening paper. 34. Stock with Acoustipack Lite and Felt in Cup Floors, Newplast, Stiffened Craft Felt over the driver, and Shure 840 Pads 35. Stock with Acoustipack Lite and Felt in the Cup Floors, Newplast, Stiffened Craft Felt over the driver, and Stock Pads 36. Stock with Acoustipack Lite and Felt in the Cup Floors, Newplast, Stiffened Craft Felt over the driver, and FA-003 Pads N. 25x60x70 mm cotton has been notched to fit around the shock absorbers and jack, placed over Acoustipack Lite in cup. Cutting off the shock absorbers is not required. Removing the rubber shock absorber caps gives you a bit more room to work but this is also optional. If you remove them, save them in case you want to go back to stock. 37. Stock with Acoustipack Lite and Felt in the Cup Floors, Newplast, Stiffened Craft Felt over the driver, Cotton, and Shure 840 Pads 38. Stock with Acoustipack Lite and Felt in the Cup Floors, Newplast, Stiffened Craft Felt over the driver, Cotton, and Stock Pads 39. Stock with Acoustipack LIte and Felt in the Cup Floors, Newplast, Stiffened Craft Felt over the driver, Cotton, and FA-003 Pads O. For DBV #2, cut 10x60x70 mm fiberglass, similarly notched for the shock absorbers, and place over 20x60x70 mm cotton. You may need more/less of each for your mod, determined by tuning 40. Stock with Acoustipack Lite and Felt in the Cup Floors, Newplast, Stiffened Craft Felt over the driver, Cotton over Fiberglass, and Shure 840 Pads 41. Stock with Acoustipack Lite and Felt in the Cup Floors, Newplast, Stiffened Craft Felt over the driver, Cotton over Fiberglass, and Stock Pads 42. Stock with Acoustipack Lite and Felt in the Cup Floors, Newplast, Stiffened Craft Felt over the driver, Cotton over Fiberglass, and FA-003 Pads 43. Stock with Acoustipack Lite and Felt in the Cup Floors, Newplast, Stiffened Craft Felt over the driver, Cotton over Fiberglass, Baffle Port Closed, and Shure 840 Pads 44. Stock with Acoustipack Lite and Felt in the Cup Floors, Newplast, Stiffened Craft Felt over the driver, Cotton over Fiberglass, Baffle Port Closed, and Stock Pads 45. Stock with Acoustipack Lite and Felt in the Cup Floors, Newplast, Stiffened Craft Felt over the driver, Cotton over Fiberglass, Baffle Port Closed, and FA-003 Pads 46. This is the same FR Graph as the one just above but with 1/24 Smoothing. This is the only FR Graph in this measurement database with any Smoothing applied. Additional Requested Pictures and Graphs 1. BMF DBV #1: With Shure 840 pads compared with Stock and FA-003 pads 2. My LCD2 P. DBV #1 and #2 Left Cup: 3x15 mm Paxmate "Ladder Rungs" over Acoustipack Lite in floor wells. 1.5x35x35 mm Creatology Stiffened Craft Felt over stock white driver dampener, Transpore overlay, and Newplast Flush Mass Loaded Baffle Compartments. Double Sided tape works best for securing stiff felt to the driver back for the permanent mod. Q. DBV#1 Left Cup: 20x60x70 mm (measured Uncompressed) Rite Aid Natural Absorbent Cotton with 10x60x70 mm (measured Compressed) Fiberglass overlaying Acoustipack Lite and Paxmate "Ladder Rungs." Baffle: Newplast Flush Mass Loaded baffle compartments, stiffened felt over stock white driver dampener and Transpore overlay. Note: Acid-free double sided tape applied to the driver grid perimeter works better than Transpore for securing the stiffened felt. DBV 1 47. 48. 49. Above: BMF DBV #1 with Shure 840 Pads - SPL FR Graph, Waterfall Plot, and Spectrogram The "DBV" designation in the Notes section of these graphs is simply my way of keeping track of various mods I'm working on. This mod configuration is a variation of BMF V8.1 described with pictures in "The Fostex T50RP Mods Summary Links" WIKI started by Ardilla. This mod is fast and neutral with excellent bass extension, texture, and definition. Mids are properly placed, clear, and lush, particularly for vocals and acoustic music. Treble extension, detail, and shimmer are very good without fatigue. Imaging is precise, channel balance is perfect, and soundstage is wide for a closed 'phone. Note: I inadvertently failed to list four important mod components in the Notes Section of my DBV graphs, above: 1. 3x1 mm bass ports over the black cup vent felt on the inside of the cups 2. Baffle ports are sealed with GE Silicone II 3. Dynamat (or FatMat) with self-adhesive felt overlay around the ear side of the drivers 4. Shure 840 pads Note, also, that I typed in the wrong dimensions for the bass ports in the Notes section of these graphs. Instead of 2x2 mm bass ports for these DBV measurements, the actual bass ports are 3mm wide and ~1 mm high - and placed over the center of the lowest of the 4 cup vents. I used a Dremel cutting tool to remove all 4 shock absorber posts inside each cup. This makes it easier to place the cotton and fiberglass overlay. I don't know if removing the shock absorbers improves the sound quality but it is possible because the cotton/fiberglass lays flatter and it's more uniformly distributed than when the shock absorbers remain in place. Removing the shock absorbers is not irreversible because they can be super glued back in place. DBV #1 with T50RP Pads 50. 51. 52. Above: DBV #1 with T50RP Pads - SPL FR Graph, Waterfall Plot, and Spectrogram DBV #1 with FA-003 Pads 53. 54. 55. Above: DBV #1 with FA-003 Pads - SPL FR Graph, Waterfall Plot, and Spectrogram DBV 2 56. DBV #2 Left with Shure 840 Pads Compared to All Stock T50RP Left 57. DBV #2 Left with Shure 840 Pads Compared to All Stock T50RP Left. 58. DBV #2 Left with Shure 840 Pads compared to All Stock T50RP Left. 59. DBV #2 Right with Shure 840 Pads compared to All Stock T50RP Right. 60. DBV #2 Right with Shure 840 Pads compared to All Stock T50RP. 61. DBV #2 Right with Shure 840 compared to All Stock T50RP Right. 62. DBV #2 Left with Stock Pads SPL FR 63. DBV #2 Left Stock Pads Waterfall Plot 64. DBV #2 Left Stock Pads Spectrogram 65. DBV #2 Right with Stock Pads SPL FR 66. DBV #2 Right with Stock Pads Waterfall Plot 67. DBV #2 Right with Stock Pads Spectrogram 68. DBV #2 Left with Inner Tube Modded FA-003 Pads SPL FR 69. DBV #2 Left with Inner Tube Modded FA-003 Pads Waterfall Plot 70. DBV #2 Left with Inner Tube Modded FA-003 Pads Spectrogram 71. DBV #2 Right with Inner Tube Modded FA-003 Pads SPL FR 72. DBV #2 Right with Inner Tube Modded FA-003 Pads Waterfall Plot 73. DBV #2 Right with Inner Tube Modded FA-003 Pads Spectrogram 74. DBV #2 Left with Taped on FA-003 Pads SPL FR 75. DBV #2 Left with Taped on FA-003 Pads Waterfall Plot 76. DBV #2 Left with Taped on FA-003 Pads Spectrogram 77. DBV #2 Right with Taped on FA-003 Pads SPL FR 78. DBV #2 Right with Taped on FA-003 Pads Waterfall 79. DBV #2 Right with Taped on FA-003 Pads Spectrogram *****End of Incremental Mods and Measurements***** My LCD2 Measurements Triflange and Foam Tip Mounted Mic Comparisons 80. LCD2 v.1 Left: Triflange Mic compared with Foam Mic 81. LCD2 v.1 Left: Triflange Mic compared with Foam Mic 82. LCD2 v.1 Left: Triflange Mic compared with Foam Mic 83. Audeze's SPL FR Graph of my LCD2 v.1 All Stock T50RP T40RP T20RP Measurements with Triflange and Foam Tip Mounted Mics Stock T50RP - Triflange and Foam Tip Mounted Measurement Comparisons 84. T50RP Left: with Triflange Mic compared with Foam Mic 85. T50RP Left: Triflange Mic compared with Foam MIc 86. T50RP Left: Triflange Mic compared with Foam Mic 87. T50RP Right: Triflange Mic compared with Foam Mic 88. T50RP Right: Triflange Mic compared with Foam Mic 89. T50RP Right: Triflange Mic compared with Foam Mic Stock T40RP compared to Stock T20RP with Foam Tip Mounted Mic 90. T40RP Left compared to T20RP Left using Foam Mic 91. T40RP Left compared to T20RP Left using Foam Mic 92. T40RP Left compared to T20RP Left using Foam Mic 93. T40RP Right compared to T20RP Right using Foam Mic 94. T40RP Right compared to T20RP Right using Foam Mic 95. T40RP Right compared to T20RP Right using Foam Mic Note: All DIY measurements were made with the same methodology and measurement chain using a Triflange Mic unless stated otherwise below each graph. About Measurements and Tuning Consider the graphs, select the various components you want to try, and build your mod. Here is where the real work begins --> tweaking, tuning, and testing one component change at a time to improve and "dial in" the sound you want. You can tweak: cotton thickness, fiberglass thickness if used, bass port size vs stock, modified baffle port size vs stock, Grodan Rock Wool thickness if used, pads used, Dynamat or FatMat vs without, additional acoustic foam in the cup and/or on the ear side of the driver, cotton vs fiberglass vs felt of different types and layers over the ear side of the drivers, omitting any of these components, and adding anything else you're interested in trying. You can literally tune for bass, midrange, or treble emphasis or go for neutral which is what I try to achieve. Be aware that changing one component will likely effect others in your design. Based on my experiments, "the total (SQ) is greater than the sum of its parts." Remember that FR graphs provide only an idea of how a mod may sound relative to another mod configuration. You cannot rely on others' opinions and you cannot know how a mod configuration will sound until you build, tune, and test for yourself. A mod's perceived SQ may be better, or worse, than suggested by its FR graph. This may result from an interaction of variables including your equipment and audio chain, source and file type, your personal SQ preferences, your hearing acuity and psychoacoustic factors such as Placebo Effect, Selective Perception Bias, Expectation Bias (positive and negative), Confirmatory Bias, the ephemeral nature of auditory memory, and Cognitive Dissonance. You must take anyone's mod and "make it your own." Tweaking, or tuning, is key. There are no "slam dunks." Consider and compare these measurements relative to one another. Do not directly compare these measurements with someone else's measurements. Submitted FWIW & YMMV. Some Additional Mod Photos R.