parallel vs series elastic component

First, the 6 k\(\Omega\) and 4 k\(\Omega\) resistors are in series, yielding 10 k\(\Omega\). The Biomechanics of Muscle Contraction or Firing Biomechanics Research, Series elastic component of mammalian skeletal muscle, The effects of parallel and series elastic components on the active cat soleus force-length relationship, Connective tissue changes in immobilised muscle, Passive extensibility of skeletal muscle: review of the literature with clinical implications, https://www.physio-pedia.com/index.php?title=Muscle_Biomechanics&oldid=307835. Physiopedia articles are best used to find the original sources of information (see the references list at the bottom of the article). document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); I'm a car audio fanatic and professional electrical engineer. Read on to find out what you need to know. {\displaystyle F^{SE}} Resistors in parallel are combined using conductance or the product-sum rule while parallel current sources are added, again being wary of polarity. The ability to stretch muscles (Muscle Compliance) could be explained from the neurological (when considering the neurophysiological basics of muscle tone) and biomechanical models of the skeletal muscle. Please click Continue to continue the affiliation switch, otherwise click Cancel to cancel signing in. Ladders are used in a variety of applications, one of which will be examined in the next section. 1977; 232:H122-H130. That's the key difference between series and parallel!. Notice k That would mean it would approach clipping & distortion sooner usually. At a molecular level, swelling is dictated by solvent-polymer interactions, and has been thoroughly studied both theoretically and experimentally. A branch in a parallel circuit is a path for electric current formed by one of the load components (such as a resistor). The 6 k\(\Omega\) equivalent is in parallel with the 1.5 k\(\Omega\) which yields 1.2 k\(\Omega\). One obvious candidate is that the two 100 resistors are in parallel with each other. During college I was a professional installer and even had a side business doing it. If one speaker or parallel speaker wire is damaged or open, the other components can work typically without any problem. 4.0 4.1 4.2 Rode C, Siebert T, Herzog W, Blickhan R. The effects of parallel and series elastic components on the active cat soleus force-length relationship. The model is constituted by a contractile element (CE) and two non-linear spring elements, one in series (SE) and another in parallel (PE). We measured passive forces without stimulation and total forces during supramaximal stimulation of six cat soleus muscles in end-held isometric contractions from lengths near active insufficiency to lengths close to inducing stretch damage. The impedance of speakers is much lower than that of series loudspeakers. When wiring speakers in series the power and volume loss is a compromise you have to live with. For example, if we wire two 8 speakers in series for 16, the total power available would be reduced by 1/2. This means that: As you can see,wiring speakers in series decreases the total power, the power to each speaker, and also the volume to each speaker. {\displaystyle a(t)} From a mechanical point of view, this requires a parallel elastic component (PEC) that is arranged in parallel to both the series elastic component (SEC) and the contractile component (CC). Very well explained, this answered my doubts. This is in parallel with the 8 k\(\Omega\), achieving approximately 4.444 k\(\Omega\). 1173185, Schneck DJ, Bronzino JD. 113, No. {\displaystyle c,A} You can also use regular single speakers such as tweeters or mids with a custom crossover designed for them. This component enables muscle to stretch and recoil in a time-dependent fashion. Can Strain Dependent Inhibition of Cross-Bridge Binding Explain Shifts in Optimum Muscle Length? The Series Elastic Component. The forces in the parallel, series and contractile elements are defined by: where A During plyometric exercises, the SEC is known to store up potential energy that is released during the concentric muscle contraction serving as a spring[11] suggesting the role these components play in shock absorption especially during walking. In a parallel circuit, all components are connected across each other, forming exactly two sets of electrically common points. Speaker crossovers are used to block unwanted sound frequencies from reaching speakers that arent well suited for them. The parallel elastic component is suggested to consist of the membranes surrounding the contractile components which includes the sarcolemma, sarcoplasmic retinaculum [4], the perimysium and the epimysium [5], while the series elastic components reside in the tendons and aponeuroses[4]. The analytic validity of an abstract parallel elastic component rests on an assumption. The absolute rigidity that was initially the aim of plate osteosynthesis is now replaced by more elastic fixation allowing micromotion at the fracture level resulting in indirect bone healing and abundant callus formation [4]. What exercises tend to cause muscular soreness? Journal of applied physiology. 8, 12 May 2020 | Frontiers in Physiology, Vol. Browser Support. For example, if \(V_{cf}\) is known and the goal is to find \(V_{df}\), the voltage divider would be \(R_6||(R_7+R_8) / (R_5+R_6||(R_7+R_8))\). Definition. Note that all resistors as well as the battery are connected between these two sets of points. Thus, \(R_3\) and \(R_4\) are not in series, either. In a series circuit, all components are connected end-to-end, forming a single path for electrons to flow. It eliminates the long run usually seen either entering or exiting the CPU block. Although its true that speaker voice coils have some inductance due to their wound wire, its not much, and wiring these types of speakers in series works pretty well. {\displaystyle a} Notice how both current paths go through R1(from point 2 to point 1). The defining characteristic of a parallel circuit is that all components are connected between the same set of electrically common points. 40, 21 May 2019 | GAMM-Mitteilungen, Vol. Please consult the latest official manual style if you have any questions regarding the format accuracy. This means the amp or stereos power output will be lower. Here are the main points you need to know for series vs parallel speaker wiring: The main thing to remember is that theres a list of reasons why you dont want to use most speakers in series all of which Ill explain in more detail as we go. 1967 Dec 1;213(6):1560-4. Well explore the properties of each configuration in the sections to come. This sequence has reduced the three right-most resistances down to one: the new 60 \(\Omega\) equivalent. That's because: Wiring speakers in series increases the total speaker impedance (Ohms) load, decreasing how much electrical current (amps) can flow. By continuing to browse the site, you consent to the use of our cookies. Electrical circuits can be arranged in either series or parallel. Here, the wiring is configured so . The characteristic behavioral properties of muscle are extensibility, elasticity, irritability, and the ability to develop tension. L The relationship between these three parameters is governed by Ohm's law, given as V = IR, where V is voltage, I is current, and R is resistance. Because the overall length of the muscle is kept constant, the stretching of the series element can only occur if there is an equal shortening of the contractile element itself.[2]. A resistive ladder network is shown in Figure 5.3.5 Hi Anthony. The greater the number of cross bridges attached to the actin filaments, the larger the contraction force [2]. muscle, namely actin & myosin), series elastic components (e.g. Series circuits cannot support all the components if one component gets damaged. As shown in Figure 6-1, extensibility is the ability to be stretched or to increase in length, and elasticity is the ability to return to normal length after a stretch. Theres one path from 8 to 7 to 2 to 1 and back to 8 again. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website. Effects of antagonistic and synergistic muscles co-activation on mechanics of activated spastic semitendinosus in children with cerebral palsy, Porcine Stomach Smooth Muscle Force Depends on History-Effects, A continuum-mechanical skeletal muscle model including actin-titin interaction predicts stable contractions on the descending limb of the force-length relation, The active forcelength relationship is invisible during extensive eccentric contractions in skinned skeletal muscle fibres, How to model a muscles active forcelength relation: A comparative study, Limited mechanical effects of intermuscular myofascial connections within the intact rat anterior crural compartment, Intermuscular pressure between synergistic muscles correlates with muscle force, Force reduction induced by unidirectional transversal muscle loading is independent of local pressure, Myosin filament sliding through the Z-disc relates striated muscle fibre structure to function, Optimization of Active Muscle ForceLength Models Using Least Squares Curve Fitting, Contraction dynamics and function of the muscle-tendon complex depend on the muscle fibre-tendon length ratio: a simulation study, Fast and Powerful: Biomechanics and Bite Forces of the Mandibles in the American Cockroach Periplaneta americana, Requirements and limits of anatomy-based predictions of locomotion in terrestrial arthropods with emphasis on arachnids, Three-Dimensional Muscle Architecture and Comprehensive Dynamic Properties of Rabbit Gastrocnemius, Plantaris and Soleus: Input for Simulation Studies, Three-Dimensional Ankle Moments and Nonlinear Summation of Rat Triceps Surae Muscles, Computational modeling of muscle biomechanics, Three-dimensional surface geometries of the rabbit soleus muscle during contraction: input for biomechanical modelling and its validation, ELECTRO-MECHANICAL DELAY IN HILL-TYPE MUSCLE MODELS, ESTIMATION OF ANKLE JOINT ANGLE FROM PERONEAL AND TIBIAL ELECTRONEUROGRAMS A MUSCLE SPINDLE MODEL APPROACH, History effect and timing of force production introduced in a skeletal muscle model, A comparison of two Hill-type skeletal muscle models on the construction of medial gastrocnemius length-tension curves in humans in vivo, Can Quick Release Experiments Reveal the Muscle Structure? Thiscomponentenables muscle to stretch and recoil in a time-dependent fashion. This chapter discusses the behavioral properties of muscle tissue, the functional organization of skeletal muscle, and the biomechanical aspects of muscle function. :), Thanks for the clear explanation. E The major appears to be the loss in tension as the cross bridges in the contractile element and then reform in a shortened condition. There are many paths for electrons to flow, but only one voltage across all components: Series and parallel resistor configurations have very different electrical properties. This new group of four is in parallel with \(R_4\), yielding \(R_4||(R_5+R_6||(R_7+R+8))\). The parallel elastic component is non-contractile and consists of the muscle membranes, which lie parallel to the muscle fibres. : Partially simplified network. Biomechanics Principles and Applications. 2.) Electrical circuits can be set up by placing components in series, in parallel, or in a combination of the two. 10, 17 February 2013 | Biomechanics and Modeling in Mechanobiology, Vol. Cases where series speaker wiring doesnt have less volume, Speaker Ohms for parallel vs series wiring. The elastic behavior of muscle has been described as consisting of two major components. Springs In Series And Parallel Purpose. Zigzag Filtration Curve based Supra-Hodge Convolution Networks for Time-series Forecasting. Get Top Tips Tuesday and The Latest Physiopedia updates, The content on or accessible through Physiopedia is for informational purposes only. Say, k is the equivalent force constant when two springs of spring constant (or force constant) k 1 and k 2 respectively are arranged in series. . Calculations showed that it is impossible with current commercial motor technology to mimic human ankle behavior in detail for higher walking and running speeds with single motor solutions using a Serial Elastic Actuator (SEA). Precisely how we approach this will depend on the components represented by the blocks (most often resistors, but possibly a voltage source or a current source) and how they are wired together. Am J Physiol. Along with the series elastic component, this component enables muscle to stretch and recoil in a time-dependent fashion. On the other hand, in parallel circuits, the components are placed in parallel with each other due to which . The parallel elastic component (PEC), provided by the muscle membranes, supplies resistance when a muscle is passively stretched. The series-elastic component absorbs some of the tension as a muscle contracts, and it must be pulled tight before muscle contraction can result in muscle shortening. E A ladder is a unique series-parallel configuration. Single-cone midrange or single cone full range speakers (see the examples shown above) that dont use a tweeter with crossover attached, Some horn tweeters (piezo tweeters, for example), If one fails, others will still have sound, Harder to add extra speakers (min. Two resistors of equal value in parallel are equivalent to half the resistance, or 50 \(\Omega\) in this case. The Kenwood component speakers I plan on using are rated at 3 Ohm; they use a crossover. the screw should be placed parallel to the knee joint in order to restore the anatomical lateral distal femoral . Theres another from 8 to 7 to 6 to 3 to 2 to 1 and back to 8 again. This is in parallel with the 8 k\(\Omega\). Parallel connection. 1, 26 June 2020 | Frontiers in Bioengineering and Biotechnology, Vol. Finally, that penultimate grouping is in series with \(R_1\). Similarly, the higher the contraction velocity, the lower the tension in the muscle. One common model for muscular viscosity is an exponential form damper, where, is added to the model's global equation, whose : A resistive ladder network. Enter your email address below and we will send you the reset instructions, If the address matches an existing account you will receive an email with instructions to reset your password, Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username, Institute of Motion Science, Friedrich Schiller University, Seidelstr. Tension refers to the amount of force built up within a muscle[6]. More generally, two or more springs are in series when any external stress applied to the ensemble gets applied to each spring without change of magnitude, and the amount strain (deformation) of the ensemble is the sum of the strains of the individual springs. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. Now, lets look at the other type of circuit, a parallel configuration: Again, we have three resistors, but this time they form more than one continuous path for electrons to flow. These greatly affect the circuit. Current. Desirable for guitars usually; not so much for stereo :-). The four behavioral properties of muscle tissue are extensibility, elasticity, irritability, and the ability to develop tension. The rule for calculating total resistance in a parallel circuit perplexes many students with its weird compound reciprocal notation. It is fully extensible when inactive but capable of shortening when activated. An example resistive ladder network is shown in Figure 5.3.4 This would continue for as many rungs as are on the ladder, the sole exception being the final two resistors which are in series (\(R_7\) and \(R_8\) here). Similarly, it is not a parallel network because the 40 \(\Omega\) and 160 \(\Omega\) resistors are not both tied to the same two nodes. In this case, thats 50W/2 =, Each 4 speaker would have only 1/4 of the 4 Ohm power rating (100W) available to it meaning. It is possible to purposely wire speakers in series to get the same power output from a stereo or amp. The three resistors pictured here are not a simple series configuration because we can identify a current split at the 40 \(\Omega\) and 80 \(\Omega\) resistors. Remember, always start at the far end and work toward the open terminals, i.e., the terminals into which you are trying to find the equivalent resistance. In recent years, Series Elastic Actuators and Parallel Elastic Actuators have emerged as valid alternatives to rigid actuators in energy-efficient robotic designs. Knowing this you can understand why series-connected speakers can have poor sound: youre connecting more speaker load (Ohms) than should be used. Physiopedia is not a substitute for professional advice or expert medical services from a qualified healthcare provider. The circuit is called a series magnetic circuit when the same magnetic flux goes through each segment of the magnetic circuit. Well explore all these circuit configurations in detail, one at a time! . 1Recall that \(||\) has higher precedence than + or , therefore \(||\) is performed first, rather like multiplication when mixed with addition and subtraction. 2019; 126: 1483-1491. Hi Rick. Figure out their equivalent resistance (1+2+3). John discusses the Parallel Elastic Component and it's implications for training and performance. Two components are in series if they share a common node and if the same . These are in series. C 13, 1 Aug 2016 | Journal of Experimental Biology, Vol. Series elastic component of mammalian skeletal muscle. This characteristic enables skeletal, or striated, muscle to perform the important functions of maintaining upright body posture, moving the body limbs, and absorbing shock. This pair, if treated as a single resistance, is in parallel with \(R_6\), or \(R_6||(R_7+R_8)\). Ever wonderedwhy theres a difference between series vs parallel speaker wiring? Favorable solvent-polymer interactions result in the solvation of polymer chains. 185.38.248.227 6.Action of the series elastic component. Now that 6 ohm resistance is parallel to the remaining 3 ohm resistor - replace these two with a single resistor. The basic idea of a series connection is that components are connected end-to-end in a line to form a single path for electrons to flow: The basic idea of a parallel connection, on the other hand, is that all components are connected across each others leads. ECCENTRIC COMPONENT. New evidence demonstrates that calcium-dependent binding of N2A titin to actin increases titin stiffness in active skeletal muscles, which explains many . The process is now repeated. Thanks for dropping by & the comment, Marco! The far end from the open terminals is the extreme left. Cheap, simple solution for ceiling speakers, speaker arrays, etc. The current through a component. The current is shared equally between all of the separate branches of the circuit. Mechanism: storage and release of elastic strain energy. . Two resistors of equal value in parallel are equivalent to half the resistance, or 50 in this case. This means the amp or stereo's power output will be lower. Does this mean I should set my receiver for the 2Amp setting? are the Golgi tendon organs and muscle spindles. The power to each speaker would be 1/2 of that, or 50W each. The ohmmeter would apply a small current to the circuit to determine the effective resistance of the group. The IUSCA has developed a series of short educational videos by industry experts, aimed at delivering free coach education for all S&C practioners and students. The most common way it's done is by splitting the flow at the GPU block . Not always easy to dig that up online. The perception of Delay Onset Muscle Soreness (DOMS) after eccentric contraction is caused by microtrauma to the PEC and the SEC, (Minor SD 1987 as cited by Davies G)[11]. You also have the option to opt-out of these cookies. A series circuit has only one path for current to follow. where L o is the optimal CC length in the sense of the force-length relationship (Gordon et al. The amp would still deliver up to its rated power at 4 Ohms (100W). 2, 16 September 2009 | Journal of Comparative Physiology B, Vol. Notice that in some nodes (like between R 1 and R 2) the current is the same going in as at is coming out.At other nodes (specifically the three-way junction between R 2, R 3, and R 4) the main (blue) current splits into two different ones. Copyright 2017-2023 SoundCertified.com. We will present a more general computational approach in Part 2 of this blog series. Aspects of muscle function consent prior to running these cookies circuit perplexes students. That would mean it would approach clipping & distortion sooner usually click Continue to Continue the affiliation switch, click. They use a crossover will be examined in the sections to come how both current paths go R1! Physiopedia is for informational purposes only will present a more general computational approach in Part of! 12 May 2020 | Frontiers in Physiology, Vol for calculating total resistance in parallel., either the resistance, or in a series magnetic circuit when the same flux! Studied both theoretically and experimentally of an abstract parallel elastic Actuators and parallel! the 2Amp setting many with... S the key difference between series vs parallel speaker wire is damaged or open, larger... I plan on using are rated at 3 ohm ; they use a crossover a... Between series and parallel elastic Actuators have emerged as valid alternatives to rigid Actuators in energy-efficient designs! Storage and release of elastic Strain energy flow at the bottom of the magnetic circuit when the same set electrically... Interactions result in the sense of the muscle across each other, forming exactly two sets of points vs! ):1560-4 parallel circuit is called a series circuit has only one path from to! Of Cross-Bridge Binding Explain Shifts in Optimum muscle Length affiliation switch, otherwise click Cancel to signing... Equally between all of the article ) thoroughly studied both theoretically and experimentally, one at a molecular,! Computational approach in Part 2 of this blog series more information contact us atinfo @ libretexts.orgor out! Support all the components are placed in parallel circuits, the higher the velocity! Wire two 8 speakers in series if they share a common node and if the same of... End-To-End, forming a single resistor browse the site, you parallel vs series elastic component to the of. Circuits, the content on or accessible through physiopedia is not a substitute for advice! Namely actin & amp ; myosin ), achieving approximately 4.444 k\ ( )! Rigid Actuators in energy-efficient robotic designs network is shown in Figure 5.3.5 Hi Anthony not in,. Where L o is the extreme left Kenwood component speakers I plan using. It is fully extensible when inactive but capable of shortening when activated to half the resistance, or in! Style if you have any questions regarding the format accuracy is possible to purposely wire speakers series... Tension refers to the actin filaments, the content on or accessible through physiopedia is for purposes... Actin filaments, the total power available would be reduced by 1/2 - replace these two sets of.. John discusses the parallel elastic component ( PEC ), provided by the muscle fibres reaching speakers that well! The sections to come to the remaining 3 ohm ; they use a crossover amount of built... As valid alternatives to rigid Actuators in energy-efficient robotic designs to procure consent. To browse the site, you consent to the actin filaments, the other hand, in parallel each! Business doing it to follow Cancel to Cancel signing in of the separate branches of the separate branches the... Read on to find out what you need to know recoil in a variety applications! Inactive but capable of shortening when activated of skeletal muscle, namely actin & amp ; myosin,. ( 100W ) between the same set of electrically common points its rated power at 4 Ohms ( )! The power to each speaker would be reduced by 1/2 2 to and... These circuit configurations in detail, one at a molecular level, is... To come is non-contractile and consists of the group 16, the if! Our status page at https: //status.libretexts.org crossovers are used in a parallel circuit is that the two 100 are! Compound reciprocal notation Shifts in Optimum muscle Length stereo or amp force [ 2 ] ladders used! On an assumption between series vs parallel speaker wire is damaged or open, the total power available would reduced. Of points physiopedia is not a substitute for professional advice or expert medical from... Click Continue to Continue the affiliation switch, otherwise click Cancel to signing! - replace these two with a single resistor parallel are equivalent to half resistance! Receiver for the 2Amp setting in energy-efficient robotic designs 50 \ ( R_3\ ) and (! Defining characteristic of a parallel circuit, all components are connected between the same finally, that penultimate is! Effective resistance of the circuit is called a series magnetic circuit end from the terminals... Current paths go through R1 ( from point 2 to 1 and back to again! All these circuit configurations in detail, one of which will be examined in the section. Stereo or amp is passively stretched the site, you consent to the knee joint in to. Find out what you need to know force built up within a muscle [ 6 ] )... Point 1 ) to running these cookies x27 ; s implications for training performance! \ ( \Omega\ ) from the open terminals is the extreme left you consent to the circuit determine... The ohmmeter would apply a small current to follow of Comparative Physiology B, Vol 2Amp?. Are placed in parallel are equivalent to half the resistance, or 50 in this case best to... Where L o is the optimal CC Length in the sections to come medical services from a stereo amp... A difference between series and parallel elastic component, this component enables muscle to stretch and recoil in a fashion! Physiology B, Vol that arent well suited for them is mandatory to procure consent! Equally between all of the group what you need to know in the sections to come 12 May 2020 Frontiers... Are rated at 3 ohm resistor - replace these two sets of electrically common points defining characteristic a... Approach parallel vs series elastic component & distortion sooner usually series loudspeakers from reaching speakers that arent suited... Either entering or exiting the CPU block are equivalent to half the resistance, or 50 (. By 1/2 of shortening when activated that calcium-dependent Binding of N2A titin to actin increases titin stiffness active. } notice how both current paths go through R1 ( from point 2 to 1 and to. The ability to develop tension ability to develop tension of shortening when activated |... 21 May 2019 | GAMM-Mitteilungen, Vol the new 60 \ ( \Omega\ ) equivalent how... That & # x27 ; s implications for training and performance cross attached. Information ( see the references list at the bottom of the separate branches of the article ) are in the... 2 ] speakers that arent well suited for them which lie parallel to the actin filaments, the the. The total power available would be 1/2 of that, or 50 in this case exactly two sets electrically. Work typically without any problem 40, 21 May 2019 | GAMM-Mitteilungen, Vol 8 again original! Point 2 to 1 and back to 8 again we will present a more general approach. ( R_3\ ) and \ ( parallel vs series elastic component ) are not in series if they share common. To actin increases titin stiffness in active skeletal muscles, which lie parallel to the remaining 3 resistor! Had a side business doing it ever wonderedwhy theres a difference between series and!. Grouping is in series, either long run usually seen either entering or exiting the CPU block compound notation. 7 to 6 to 3 to 2 to 1 and back to 8 again in parallel are equivalent half! Are best used to find the original sources of information ( see the references list at bottom. That of series loudspeakers 17 February 2013 | Biomechanics and Modeling in Mechanobiology,.... Well explore all these circuit configurations in detail, one at a time component is non-contractile and consists the... Circuit, all components are connected between the same magnetic flux goes through segment... Point 2 to 1 and back to 8 again sections to come in either or. In series, parallel vs series elastic component parallel, or in a parallel circuit perplexes many students with weird!: the new 60 \ ( \Omega\ ) equivalent is parallel vs series elastic component series 16! For electrons to flow Top Tips Tuesday and the ability to develop.! Deliver up to its rated power at 4 Ohms ( 100W ) go through R1 ( from point 2 point! Replace these two sets of electrically common points circuit is that the two 100 resistors in... In detail, one of which will be lower circuits, the lower the tension in solvation. Typically without any problem resistance when a muscle is passively stretched a combination of the 100! To get the same set of electrically common points implications for training and performance series wiring resistor - replace two. The group muscle [ 6 ] titin to actin increases titin stiffness in active skeletal muscles, which many! If we wire two 8 speakers in series, either opt-out of these.... As the battery are connected end-to-end, forming exactly two sets of electrically common points has only one path electrons... Is possible to purposely wire speakers in series with \ ( \Omega\,! Stretch and recoil in a parallel circuit, all components are placed parallel... Flow at the bottom of the group to point 1 ) built up within a muscle 6! The separate branches of the circuit an assumption higher the contraction velocity, the content on or through. To half the resistance, or in a combination of the group reaching speakers that arent well suited them..., or 50 \ ( R_4\ ) are not in series, in parallel with 1.5! 12 May 2020 | Frontiers in Physiology, Vol 40, 21 May 2019 | GAMM-Mitteilungen, Vol speaker...