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Biocellulose and Its Use In Headphones-Earphones (referring the recent iem example: Vsonic GR-07 (R07)

Discussion in 'Sound Science' started by baycode, Aug 25, 2011.
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  1. Baycode
    ==> What is biocellulose?
           Why it is used as an acoustic equipment component?
    These questions arouse after listening to the VSonic GR-07 iem.
    It is supposed that, VSonic used nearly 100 very thin layers of biocellulose membranes (although its mentioned as bio-cellular on the pitcure), fused together by a special process to produce the biocellulose diaphragm of GR-07.
    Source: www.portafi.com
    I did a search about the biocellulose and its use as an acoustic component and, reached some interesting scientific research papers (there are not too many).
    But fist of all I want to share some basic information from Wikipedia that everybody can understand (it's stated as microbial cellulose in Wikipedia):
    ==> Microbial Cellulose:
    Microbial cellulose is a form of cellulose that is produced by bacteria. It is widely used in the traditional Filipino dessert Nata de coco. Microbial cellulose was first confirmed as cellulose in 1886.


    Bacteria from the genera Aerobacter, Acetobacter, Achromobacter, Agrobacterium, Alacaligenes, Azotobacter, Pseudomonas, Rhizobium and Sarcina synthesize cellulose. However, only the Acetobacter species produce enough cellulose to justify commercial interest. The most extensively studied member of the Acetobacter species is Gluconacetobacter xylinus, formerly known as Acetobacter xylinum.
    G.xylinus extrudes glucan chains from pores into the growth medium. These aggregate into microfibrils, which bundle to form microbial cellulose ribbons. Various kinds of sugars are used as substrate. Production occurs mostly at the interface of liquid and air.

    Differences with plant cellulose

    Some advantages of microbial cellulose over plant cellulose include:
    1. Finer and more intricate structure
    2. No hemicellulose or lignin need to be removed
    3. Longer fiber length: much stronger
    4. Can be grown to virtually any shape
    5. Can be produced on a variety of substrates
    6. The formula of the media used and the strain of Acetobacter xylinum will determine the quality of the pellicle
    7. More absorbent per unit volume


    Disadvantages for commercial use

    Some issues that have prevented large scale commercialization so far include:
    1. High price (about 100 x more than plant cellulose)
      1. Because of high priced substrates: sugars
      2. Low volumetric yields
    2. Lack of large scale production capacity
    3. Timely expansion and maintenance of the cell culture for production


    One continuing mystery surrounding microbial cellulose is its exact biological function. A. xylinus recently renamed as "Gluconacetobacter xylinus" is a successful and prevalent bacterium in nature, frequently finding a home in rotting fruits and sweetened liquids. The most familiar form of microbial cellulose is that of a pellicle on the top of a static cultured growth media. It has thus been hypothesized that cellulose acts as a floatation device bringing the bacteria to the oxygen rich air-media interface. This hypothesis has largely been discredited by experiments conducted on submerged oxygen-permeable silicone tubes that show cellulose grows well submerged if enough oxygen is present. Others suspect that cellulose is used to immobilize the bacteria in an attempt to keep it near the food source; or as a form of protection against ultraviolet light.



    Microbial cellulose is biocompatible and non-toxic making it a good candidate material for medical applications.[5] So far it has found a commercial role in some wound dressings. There is on-going research to evaluate a possible role for bacterial cellulose in the following applications:
    1. Scaffolds for tissue engineering
    2. Synthetic dura mater
    3. Bladder neck suspension
    4. Soft tissue replacement
    5. Artificial blood vessels

    Non medical

    1. Matrix for electronic paper
    2. High strength paper
    3. Diet foods
    4. Desserts: nata de coco
    5. Substrates for OLEDs
    6. Sony has use microbial cellulose as an acoustic membrane in high-end earphones
    7. It has a proposed use as a gloss surface finish in magazines
    ==> Biocellulose use as a diaphragm material is a patented process. Please read below for the very famous Sony R-10 headphones (a part of a review) which the biocellulose has its use:
    Sony apparently tried every conventional material used for forming diaphragms, found nothing which would yield the 'broad, deep sound of a room speaker system' and eventually stating that (and I quote):
    '...After a frustrating stalemate, we discovered "bio-cellulose." We found that when fed saccharides, a 2-micron-long bacterium,
    called Acetobacter aceti, produces very fine cellulose fibres 200-400 angstroms in diameter which are called bio-cellulose.
    With leading-edge biotechnology techniques, the bio-cellulose culture becomes 2mm thick in about two days. It is then
    dehydrated and compressed to a thickness of 20 microns in a diaphragm die.'
    Yeah, I know: if this were the April issue...but it isn't. Apparently, this material, straight out of the cyberpunk epic Neuromancer, provides the velocity of aluminium or titanium with the 'warm, delicate sound' of paper. 
    Whatever the stuff is, it's the subject of a joint patent between Sony, the Ajinomoto Company and the Research Institute for Polymers and Textiles of the Agency for Industrial Science and Technology.
    ==> I read some interesting statements on some forum posts that biocellulose membrane in iems can get infected by the fungus or some bacteria. This is funny because the same product can be used as a blood vessel and heart valve component (under research). Some people even jokes about eating the biocellulose membranes (or even headphones/earphones). Also this is funny because cellulose is not an digestible product for human beings.
    Some previously posted statements at the head-fi says that biocellulose acts like metal (for example like aluminum). It is very fast and responsive if used as a diaphragm. By  this way, although the driver component is dynamic, it acts fast and responsive like an armature driver.
    It is stated by some users at head-fi that the sound characteristics of GR-07 sits in between the dynamic and armature drivers. Some people also stated at head-fi that they thought they were listening to an armature driven iem!
    I also have to say that the review by the respected iem reviewer ClieOS is great to understand the nature of these iems: (http://www.head-fi.org/t/536342/review-vsonic-gr07-labor-of-love).
    Some parts from the scientific papers also supports that, biocellulose diaphragms can produce very wide range of frequencies very successfully (you can read the parts on the below).
    It is not the first time in the history that the biocellulose is used in the acoustic components with the GR-07.
    Most fellow headfiers should know about once very popular earbuds: Sony MDR-E888.
    Also these examples includes the full sized headphones like Sony MDR-R10, CD3000, CD1700 and Creative Aurvana Live. But not all of  the biocelluse membrane diaphragm headphones were successful or well known (like Everglide s-500 and Panasonic RP-HC700S).
    ==> In the end lets check some information about the VSonic GR-07:
    Source: http://www.portafi.com/
    VSonic GR-07: Dynamic top-end earphones. It took the VSonic acoustic R&D team three years and three months of work, continuous improvement and overcoming obstacles to create these supremely comfortable and noise-isolating earphones.
    GR-07 are the high-end in-earphones from VSonic, fulfilling the requirements for true hi-fi music playback. The GR-07 were designed to fit stylish and beautiful over-the-ear frames and sport CCAW highly dynamic drivers.

    GR-07 biocellulose diaphragms are composed of more than a hundred layers of biological material as thin as eardrum skin. High quality sound is guaranteed.

    Drivers: 11 mm. highly dynamic CcAW type.
    Sensitivity: ≥105dB (@500 Hz test tone).
    Nominal Input Power: 10 mW.
    Maximum Input Power: 50 mW.
    Nominal Impedance: 50Ω+/-10%.
    Frequency Range: 7 Hz - 30000 Hz.
    Distortion: <0.2% @105 dB (20μpa).
    Channel Crosstalk: <1dB (@500 Hz); ≤1.5dB (@~20Hz).
    Cable: 1.30 m. 82-core non-toxic silver-plated copper.
    Plug: gold-plated (8μ24K) stereo miniplug, 3.5 mm.

    ==> Vsonic GR-07 video:
    ==> About VSonic company:
    Vsonic Electronic Company., Ltd (Shenzhen) is a high-tech corporation which possesses mighty research, development, manufacture and sales strength. And it has more than thirty middle or high-ranking professionals. Among them are two professional acoustics masters, three high-ranking engineers and three professional timbre evaluation experts. Experienced earphone design experts who had once studied in Japan are also included. And it has established the whole modern cooperation system ranging from products research, development, manufacture, sales to after service.
    Vsonic Electronic Company., Ltd (Shenzhen) sticks to the way of brand and professionalizing strategy for strategy and has earphone driver unit production equipments, modernized dustless workshop, advanced computerized checking and analyzing system which were all imported from Japan. There are professional timbre evaluation experts working both in the headquarters in China. A management system which is operated on the spot and centered on 5s management, a quality control system centered on star rank management and a corporation resource development system centered on human resources management have been set up in the long run. 
    Vsonic Electronic Company., Ltd (Shenzhen) has come to technical alliance with many internationally famous corporations in order to keep the technique forever on the cutting edge of both international and domestic level. It also possesses the most excellent technique development elites of the same industry in China. “Individuality, fashion and leading” is their products development strategy. And the patent rights of several audiovisual products are held by them and they will have been leading the technique development fashion of this industry.
    ==> ...and finally some more science (I am just putting the parts that some head-fiers may interest. I could not put the complete texts due to copyright issues):
    Please check this post first: http://www.head-fi.org/t/38843/biocellulose-as-a-diaphragm-material
    In this post at head-fi, it is stated that the first scientific paper published in 1991. Although I could not reach it (because its stated that the paper is in Japan language) I advise you to read this post first.
    ...then check these:
    MARKIEWICZ, E., HILCZER, B. Z. and PAWLACZYK, C. (Institute of Molecular Physics Polish Academy of Sciences). “Dielectric and Acoustic Response of Biocellulose”, Ferroelectrics, 304: 39–42, 2004.
    The results of dielectric response studies of the biocellulose showthat two relaxation pro-
    cesses can be distinguish: the local main chain motion at 200 K and an orientational
    motion in a mixed phase of polysaccharide and water at 325 K. The electroacoustic
    parameters of a loudspeaker with biocellulose membrane were measured in echoless
    conditions. The relationship between dielectric and mechanical properties of biocellu-
    lose was found.
    Bacterial cellulose is an interesting, renewable and biodegradable material with extended
    commercial application. The loudspeakers with biocellulose membranes were found to
    exhibit acoustic response in a wider frequency range and of higher effectivity in comparison
    with that produced of a woody tissue. Several authors [1] pointed to a relationship between
    the molecular motions of the cellulose and its physical properties. The aim of the paper
    was to correlate the dielectric and acoustic response of the biocellulose. The mechanical
    properties of the biocellulose are strongly connected with electroacoustic parameters of the
    loudspeakers, because themechanical compliance of themembrane is inversely proportional
    to Young’s modulus of the membrane material.
    The biocellulose studied was produced from Acetobacter Xylinium by Institute of
    Chemical Fibers (  L´ od´z, Poland) during the bacterial culture time 3–10 days and delivered
    to the Loudspeaker Factory TONSIL (Wrze´snia, Poland) in form of 100 mm gel pelletes.
    Römling, U. Mini-review: “Molecular biology of cellulose production in bacteria”, Research in Microbiology, 153: 205–212, 2002.
    Impact of bacterial cellulose production in medical settings and industrial applications:
    Besides its role in the natural environment cellulose biosynthesis of bacterial organisms has its impact in medical settings. Enterobacteriaceae, in particular E. coli, frequently cause nosocomial infections such as sepsis, biliary tract infections and catheter-related cystitis that are caused by biofilm-forming isolates. Since the major components of the extracellular matrix of biofilm forming E. coli have been identified, more rational approaches to prevent adhesion to catheter material can be designed. Plant-derived cellulose is used in high quantities as a starting material in various industrial branches. Since bacterial cellulose is of high purity and displays special physico-chemical characteristics, it has found numerous applications in the paper and food industry (as acoustic membrane and food texture) and in the medical field (as an artificial skin and blood vessel substitute) [9,41].
    However, the industrial production of bacterial cellulose is yet fairly inefficient, although strain selection, genetic manipulation and process optimisation have been used to enhance productivity of cellulose [21,41].
    Indrartil, L., Yudiantil, R.,  Amurwabumil, K., Jurnal, N. Y. “Application of biocellulose as an acoustic membrane”, Indonesian Journal Of Biotechnology , 6: 180-184, 1998.
    Traditionally, membrane of cone loudspeakers are made of paper (cone paper), formed with cellulose fibers. Bacterial cellulose or biocellulose is known as nata de coco which is produced by coconut water fermentation using Acetobacter. A sheet obtained from the biocellulose has good mechanical properties i.e the Young 's modulus of a sheet prepared using hotpress processing was 13 GPa.

    Improvement of the mechanical properties can be achieved by treating the biocellulose with alkali or oxidant solutions. The Young's modulus of the sheet of biocellulose has reached 23.5 GPa with tan 60.02 (an acoustic absorption property), and sound velocity as high as 4522.67 m/sec. These characters showed that biocellulose sheet prepared from coconut water fermentation showed good acoustic characteristic. It means that the replacement of cone paper loudspeaker with a cone biocellulose is prospective .

    Based on these characters, an experiment has been conducted to construct cone loudspeaker from the'biocellulose material with size and shape similar to those of marketed cone loudspeaker. Frequency respons of cone type loudspeakers made of bacterial cellulose shows that it has wide frequency range, from low to high.
    ==> This new acoustic membrane era have nearly 10 years of background.
    Finally, I think that in the near future it is possible to see some new biocellulose membrane headphone-earphones.
    Some of them might be good some of them might not. Some of them even can be fake!
    I hope to recieve contributions from fellow headfiers to this page.
    PS: Sorry for my language, my native language is not English.
    Richter Di, KarmaPhala and golov17 like this.
  2. DaBomb77766
    Wow, thanks for this post!  Very interesting stuff!  I never knew the Aurvana Live used biocellulose though.
  3. jrkong
  4. PhoenixClaw
    Wow. Thanks. For all the time we spend listening and researching on our gear I don't think we spend enough time to fully appreciate the technology behind them.
  5. kiteki
    I believe the Creative Aurvana Live is bio-cellulose on microfiber, if you look at the fuzzy surface, this is also the case with the Denon series. The Qualia 010 is apparently bio-cellulose on Vectran (SA-5000 too?), sourced from this post - http://www.head-fi.org/t/202122/the-headphone-driver-pics-thread/195#post_7703969
    The CD2000 is bio-cellulose on Vectran, source: http://reviews.cnet.com/headphones/sony-mdr-cd2000/1707-7877_7-6900011.html, http://gilmore2.chem.northwestern.edu/archive2000.htm
    CD1700 bio-cellulose on Vectran, source: http://www.gramophone.net/Issue/Page/March%201997/122/757120/
    Panasonic RP-HC700 - http://global.rakuten.com/en/store/okadadenki/item/rp-hc700/
    High quality design uses bio-cellulose diaphragm ■
    Higher purity than that from plant cellulose diaphragm, with the adoption of bio-cellulose fiber structure characterized by a very fine, low density, high rigidity. Maintaining a good balance in all bands, and high sound quality.
  6. kiteki
    off-topic but the Sony CD-900 had sapphire-coated drivers and some other models even used diamonds and platinum.
    As your post says after the R10 pic Sony indeed experimented with and pioneered many different driver materials.
    The Fostex TH900 will be released in January, a prototype model existed over 4 years ago so I'm not sure why they took such a long time to release it, perhaps Foster was waiting for a company to buy 20,000 units from them and release it as the "Denon K6060-2" "Sony IXC911111-1!" et cetera, and since that never happened they eventually decided to further advance the 448498 prototype with the newly developed 1.5+ Tesla magnetic flux density driver and improved on the Zelkova Serrata housing with a specialist Urushi (poison-ivy) traditional Japanese lacquer and then release it via their own Fostex daughter company.
    Fostex have also released speaker cones with bio-cel such as this one "f200a 8 full range alnico magnet fx series bio-cellulose cone made from kenaf with special mica composite coating discontinued get them while they last 8 70 0.45 8.21 30 89 fo-20khz 2.0 5.4s/11v 111/60 $98.00" source: http://www.who-sells-it.com/cy/speaker-components-inc-1385/madisound-catalog-5277/page-61.html
    Here is some more information with pictures - http://desk.mywork.co.kr/zboard/zboard.php?id=technical&page=1&sn1=&divpage=1&sn=off&ss=on&sc=on&select_arrange=headnum&desc=asc&no=84
  7. Baycode
    Thank you for your contribution Kiteki!
    I am wishing to receive information from head-fiers to this page.
  8. Anaxilus
    Leepery has a nice post somewhere on the derivatives of various Sony bio-cellulose drivers.  What is interesting is that Sony still makes bio-cellulose but has moved on to LCP.
  9. miceblue


    Oh snap! Seriously? [​IMG]   This sounds interesting. I'm into bioengineering (specifically tissue engineering and regenerative medicine) and I have not heard of using biocellulose for scaffolds before. Thanks for sharing! This is something to look into.
  10. jrkong


    I find this VERY surprising that you wouldn't know... or at least for a few of them
  11. miceblue


    Sorry for the late response, this thread only came to mind today after watching a tissue engineering lecture on YouTube:
    (if interested)

    Yeah, I haven't heard of using biocellulose for tissue engineering before. Most of the tissue engineering I am interested in is dealing with internal systems using polymers, stem cells, or cells from other parts of the body. From a quick Google Scholar search just now, it looks to be that biocellulose is mostly being used for external wound dressings.
  12. Modwright01
    Great Thanks !
    Just thinking about the Bio celluse in time...How it is when it is old ? My R10 has 23 years, and sounds great. I suppose It can leave lifetime if handle with care...

    What do you think ?

    Thanks a lot.
  13. customcoco
    I highly doubt it.
    A lot of the earliest r10s seem to have defective drivers, drivers that are hard to find.
    and even If you manage to find one there are strong chances that the drivers will mismatch as there are 4 versions of them... what a pain in the neck.
  14. Modwright01
    Ok. You doubt. But what about the science facts ?
    How many time a bio cellulose driver can live if it is handled with care ?
    How many time bio-cellulose can resist against time  ?
    What about my R10 ? He seems like new and sound incredibly detailed and crisp and has been bought in 90's....
    The other question : imagine someone that bought a R10 and let it in his leather case during 20 years : what about that ? The driver will be damage anyway ?

  15. customcoco
    1. I don't know anything about the science facts, I just try to be logical. Organic materials almost always tend to be less resistant to damages than metallic ones, for example. 
    2. I don't know, what do you mean by "handled with care"?
    3. That depends on what you mean by time, if has been used during that time (which would lead us to your 2nd question) or if it has been left unused which would lead us to your 5th question.
    4. Have you heard any other r10, newer ones or even ones that have been left unused for years? The comparison could be interesting… 
    5. I think that it will depend on the temperature, humidity level, dust floating in the air etc.. But yes I think that the driver will be damaged anyway, the real question is : are these damages going to cause any audible changes? I doubt that, too…
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