Voice coil rub symptoms

Voice coil rub symptoms. The frame on celestions is far from perfect, maybe that's why they sound the way they do Anyways, look at how you mount them or the screw used, ECT; that The voice coil's electromagnet is placed within a permanent magnetic field. The voice coil's electromagnet is placed within a permanent magnetic field. The two magnets interact, and every time the electromagnet's polarity changes, the interaction between the magnets changes. Jun 12, 2020 · I have pair of JBL 4301B monitors and as im a drummer and muso I fed them a little to much power whilst having a beer. They have a low hysteresis, and they are relatively small in size to achieve a more efficient design footprint. . This force, known as the Lorentz force, is determined by the Jun 27, 2012 · If you push down on the cone equally and it feels like its stiff or coil rub you may have melted it. Oct 20, 2006 · Members. What you need to do is remove the dust cap and insert vertical strips (about 1/8-1/4" wide) of shim material inside the voice coil in between the voice coil and magnet pole piece to keep cone/voice coil assembly centered. i read that this could be from voice coil rub on the capsule. This is basic and I won't go into it here, but the rule is that the value should be less than the expected nominal Impedance rating ( with some, especially older, speakers it may be just barely below the Aug 23, 2018 · The voice coil has been damp and warped. This tool does not provide medical advice. Nov 14, 2011 · Hold the woofer next to your ear with your hand holding the magnet area. Jul 7, 2017 · This causes the voice coil to rub against the sides of the gap. The sound and resistance goes away if I push the cone down at an angle on a Mar 13, 2023 · 1. An interruption in the electrical current causes this supplied to the voice coil and woofer cone, which results in an imbalance of power within the speaker. It is a speed-constant parameter, i. Check for physical damage. Have tried rotating 180° etc. May 25, 2008 · 1. Step 2. Voice coil rubs badly in one and slightly in another one. You may also notice rough acceleration, poor fuel economy, a hard-starting engine or exhaust gases that smell like fuel. At that point, the loudspeaker would fail. And it WORKED. WIth two hands spaced evenly across the cone, gently push the cone in just a bit and release. There is no indication that woofers were re-foamed. Sep 19, 2019 · I'm refoaming the woofers in a pair of kef 102. It should be pretty obvious where the problem is. . :-\\ it just went away. Jun 18, 2018 · Voice-coil actuators, Part 1: Principle basics. When I play any song on low volume without much low end… Apr 24, 2018 · Mark Wilson. After you’ve taken the speaker apart, you’ll want to clean it gently. This would be an example of a light voice coil rub. I recently received a pair of Snell Type E/3s from a relative. One woofer May 6, 2009 · You mention rubbing voice coils when you push on the cones. Choosing single or dual voice coils can also improve your audio experience. No speaker movement. Before it starts to firm up, feed an LF tone into the unit that will give a good excursion, say, 1/2" or more peak to peak. Jan 31, 2012 · Jan 30, 2012. Speaker installation The speakers can only be installed once the cables have been laid. Aug 7, 2010 #1 I have a pair of these . Second, the DVC subwoofers are more Aug 7, 2010 · Dynaco A25 voice coil rub solutions. Jan 31, 2011 · When you pull the speaker out, you cantest it this was. Oct 5, 2010 · Maybe. Oct 6, 2010 · Cut the dust cover off very carefully and use some thin, stiff paper (maybe a some 4X6 note card cut in strips) to slip between the voice coil and the speaker cone. What I expected to find was a rub throughout range or most of it. To repair this driver might be very expensive, and not worth the effort. These are 40 year old drivers so things wil happen over time. How to fix a speaker with coil rub, where the voice coil comes in contact with the magnet. Another way i like to check is take the sub out of the box and shine a flashlight at the coil if you can see it looks dark or burnt good chance you roasted it Jan 21, 2017 · As somebody already mentioned, this was not the way to fix a rubbing on the voice coil. Two out of four woofers are not centered. A thump on the magnet with a sturdy piece of wood, in the direction of the clear coil, may improve it. Oct 29, 2009 · Poor refoaming surround replacement will instigate voice coil rub. force factor Bl(x)) producing higher peak values in the time domain Jan 31, 2024 · In conclusion, understanding voice coils and impedance is crucial for tailoring your sound to perfection. Oct 22, 2018 · Poster Extraordinaire. Dec 8, 2022 · Blown voice coil. do any of you guys know how to operate on a capsule that has voice coil Feb 13, 2019 · I wonder if anyone ran into this. You will feel and hear a light scraping sound if the coil is rubbing. We hope this makes it easier for you to identify your symptoms and possible conditions. " I would think it'd be easier and faster to glue a new spider Aug 7, 2017 · Kozmik Kowboy. What happens is, too much signal causes the voice coil to overheat and actually melt - leaving a little blob of copper between the VC and the magnet. Sep 22, 2013. When combined with a position sensor, our voice coils provide quick, accurate movement with excellent repeatability. Then shift the whole assembly left until it starts to rub, then right until it starts to rub. #7. #2. Is it very discrete or will I know immediately that it's occurring? Oct 26, 2023 · Voice coil actuators are precise, direct-drive linear motors used in robotics, aerospace, medical, optics, and automotive applications for accurate motion control. Cut out the partition using the template supplied. Though the speaker will technically still work, the sound is pretty unusable. I once read how you are "suppose to" fix a rubbing voicecoil. The noise is definitely a rub, either from, as you suggested, a warped (from overheating) voice coil, or flakes of paper or other material stuck in the gap between the voice coil and pole or front plate hole. I haven't ordered new foam yet (recommendations for that that are also welcome), but I have cleaned off all the old foam and glue. When a current is applied to the coil, a force is generated. Symptoms : Scraping sound and resistance when I push the cone straight down. Nov 23, 2012 · This is a quick demo of a couple of speakers that, while they did in fact still measure a reasonable DC resistance, had some seriously toasty voice coils! T Oct 15, 2020 · This article provides an overview on how to specify or manufacture voice coils. I am worried about voice coil rubbing Jun 6, 2012 · $30 Later, I successfully refoamed the speakers and reinstalled them, yet one speaker has a slight voice coil rubbing sound when the cone is pressed down & sound is distorted when playing bassy music. Other advantages include its high accelerations and a lack of what is called cogging or commutation. Note the positions and split the difference. The surrounds were almost completely disintegrated, so I am working on replacing them myself. DIS. Thread starter vintage4; Start date Aug 7, 2010; V. When they play at mid volume, one speaker has a vibration. Having analyzed the possible cases of involvement of the shift from worn suspensions, has raised a board decision by Nov 29, 2022 · When I lightly push that driver I can hear it rub. If there is coil rub, it will be apparent. A voice coil actuator, also known as a non-commutated DC linear actuator, is a type of direct drive linear motor. Jul 14, 2012 · Put your bead of glue under the outer surround. However, both have a voice coil rub, evident at about 2khz as a sort of buzzy ringing which stops when the dome is gently touched in a specific direction. After playing some frequency Oct 11, 2019 · The pleats all look ro have a little extra wear on the bottom at 180 degrees, nothing could possibly rub from the outside. Just as the title describes, my speakers were dropped and I believe the woofer is damaged. vintage4 Active Member. IMO a former that has outgassed would rub all the time, and this can be fixed sometimes by prying off the dustcap and pushing in some very stiff shims on the side with the bubble. +1. Sound is ok when played at medium levels. No more buzz!!!! Mar 26, 2011 · Sounds like they are gonners. "Blown" is not meaningless, that's exactly what it sounds like you have. Oct 13, 2017 · When playing music and pushing any volume of bass, the woofer burps, which has always been an indication to me of voice coil rubbing when the surrounds appear to be good. In loudspeakers, more power results in more volume. They give you more connections to make full use of the amplifier. Press very gently on the cone to find where the voice coil rubs. The removal of all the old moving parts from a speaker frame and the installation of a new voice coil, spider, cone, surround, gaskets, leads and dustcap. Jun 8, 2015 · Voice coil rubbing(2) may be initiated by a rocking mode corresponding with an asymmetrical mass distribution caused by a faulty glue dispenser, originally. The speaker may have an issue if the subwoofer’s sound is noticeably low, distorted, or nonexistent. Permanent Magnet: A fixed magnet providing a stable magnetic field in which the voice coil operates. Hi-2. Am I dealing with improperly centered spider or just surround? Spider does not seem to be detached as I’ve Identify possible conditions and treatment related to your symptoms. And looking at guides this thing called voice coil rub always comes up. I flipped the speaker upside down and it works flawlessly. They voice coils start to drag when they get over hot, they may stop when they have cooled but it is unlikely, It usually sounds as you have described barky, scratchy etc, which is the expanded coil catching the sides of the magnet on its travel. If that cooling cannot happen, the coil will be fried. 8k. I got lucky on one but not the other. Choose quality cables with the appropriate cross-section for the length : your Focal dealer will be able to advise you. They started farting with voice coil to magnet rub . Using both hands, judicially and carefully push down on the cone with even pressure, taking care not to shove your finger tips through the cone. Members. 3:12 - No Coil Rub3:19 51K views 7 years ago. #1. 506 Voice coil rubbing. This phenomenon can be characterized and seen as a variation of half inductance seen from the amplifier, because that value depends directly on the minimum and maximum excursion in the displacement of the moving coil. it doesn’t change with the speed of the coil. Posted October 21, 2006. 775 LONG:28°2'58. Popping and Rattling. This is often the case with speakers which have sat for extended periods Step 1. Could be something mechanical that has come unglued and is flapping. Sensata | BEI Kimco offers a wide variety of custom linear and rotary Voice Coil Actuators (VCA). This is a common occurrence in speakers built with lower-quality materials. I took the woofer out and pressed evenly on the cone in and out. Then, to test if the subwoofer voice coil is bad, you can simply look for any signs of damage, such as burns, cracks, or tears in the speaker cone. Like linear motors, they work on the principle of a permanent magnet field and a coil winding. Jul 15, 2021 · Woofer distorts when played loud, no voice coil rub, I check the edge and spiders and there are no loose parts. This can take some time and patience which is why I like using a glue with a longer set time (like Aileen's Tacky Glue). This is a standard fix when people notice that rubbing sound with older speakers: just rotate the woofers. Also, it makes a slight buzz when no sound is passing through. Now thump the back of the speaker with your hand. To make matters worse, the adhesive used to hold the voice coil together loses its strength at high temperatures and even a minor coil rub against the top plate can dislodge some of the coil windings. These direct-drive, zero backlash Feb 12, 2023 · Symptoms Of A Bad Ignition Coil. Imagine a fuzzy decay at the end of each note. As mentioned before, the difference between the single voice coil (SVC) and the dual voice coil (DVC) is minimal and not performance-based. Then carefully use some acetone to dampen the cardboard surrounding the coil don't use too much, just enough to dampen it. #3. If the voice coil is at the rest position x=0 the instantaneous value of Bl(x=0) is maximal and generates the peak in the envelope of the sound pressure signal. Nov 25, 2004 · That means it does not get properly cooled, and that part can overheat drastically, with damage to the glue and wires falling off as a very possible result. Cleaning the tweeter to remove any bits of dust and debris that have collected inside will allow you to locate the problem better. The second however is causing me some headache. A more severe rub creates a distorted overtone that covers all your notes from start to finish. Nice amp. 2. What causes the coil rub - does the cone move positons? What causes that to happen? Jan 21, 2024 · So you just replaced the foam surrounds on your woofer and you hook it up and hear that awful scraping sound. The tool also allows you to select multiple symptoms quickly. Whatever you do, be gentle. I'm just leaving this in case it could help someone else too as it helped me. It addresses voice coil basics, bobbin materials and sizes, collars, winding techniques, configurations, tips and tricks and wire types and considerations - a valuable, concise compendium of unique knowledge. Feb 1, 2024 · Wiring options: 8-ohm dual voice coil subwoofers can be wired in parallel or series, resulting in different impedance loads. i know sennheiser doesn't fix these and they don't sell the old capsules any more. These mid bass drivers were refoamed. In the end, it all depend if you like these speakers. No wire hitting the driver from the inside. (Kind of hard to explain) If the voice coil has any rubbing going on it will have a scratchy sound. And special thanks to both of you who gave the hammer idea. Do the voice coils rub when you play music, instead of pushing on the cones? The only thing I coud think of would be to remove the dust caps and shim the voice coils so they are centered and then place the woofers in a warm place for a few days or weeks to see if they recenter themselves. I just did a bit of research and seems one potential fix the hifi guys do is to try cutting the dust cap off, slide paper down the voice coil to space it evenly, apply acetone to the spider to relax it temporarily and place a jar over the centre of the cone overnight to weight it down evenly. Aug 26, 2016 · If I feel voice coil rub, I remove the pins and gently adjust the cone slightly away from the rub, reinstall the pins and try again. Intermodulation distortion can easily be detected by using a two-tone signal with varying frequencies of the excitation tones (“bass tone sweep” or “voice tone sweep”). Table 1 - Contains the main characteristics and properties of the studied voice coil actuator. It can also cause a misfiring or stalling engine, along with a rough idle. Sometimes only when you're really cranking it. The coils may be damaged, but I think it's more of an alignment issue from years of being bashed about in cabs. If you ease the cone sideways whilst gently moving the coil, if you have a good spot, the magnet is misaligned. You can use compressed air to do this, or just a clean cloth. Aug 8, 2014 · JBL 2206 Voice Coil Rub And Rust: Post Reply the issue with using any compressed air or forward blasting action is that you force dirt into the voice coil gap Apr 19, 2008 · Apr 19, 2008. Scraping sound caused by voice coil rubbing on the top plate or pole piece. The problem is it isn't centered in the gap. Once in a while you will run into a speakers that rub in all four quadrants. There are 3 basic tests that should be done when buying or selling a speaker: 1) Measure VC DCR. How to Test a Speaker for Voice Coil Rub. D. I would be a little disgruntled if the mid wasn't fixable and May 7, 2024 · The voice coil converts electrical signals directly into linear magnetic force, providing much higher purity of motion compared to DC motors requiring separate drivetrains such as belts or gears. Mar 3, 2013 · 1. com/#ae862(this is an affiliate link. That sound is the inside of your voice coil rub 1,437. Sep 4, 2021 · Step 2: Clean the Speaker. Apr 11, 2020 · Voice coil rub. or it is a poor quality build. IF you push the cone in incorrectly---unbalanced and Aug 7, 2006 · I came to the conclusion that it was indeed minor VC rub on my a60 wooger. If not, depending on the worth of the driver, it may pay to have the coil rewound. Sep 8, 2012 · Sometimes you can get magnetic junk in the gap that will abrade the insulation on the coil. Gravity then pulls the cone the other way, back into alignment. First, the dual voice coil subwoofers give you more wiring options than the single voice coil subs. If you are playing a media file on your speakers and you hear an unpleasant sound like popping or rattling instead of music, that’s a major concern. After letting the glue dry, I pushed on all four drivers and have experienced no voice coil rub. You want the cone to move in and out as if it were active. It comprises a length of wire, wound in a circular pattern around a cylinder called the former. Figure 9 - Back emf sensitivity parameter. This is often the case with speakers which have sat for extended p Mar 21, 2023 · First, cover the magnet gap carefully by placing the protective tape over it. Distorted or Fuzzy Sound: When a subwoofer’s voice coil is blown, it will produce a fuzzy or distorted sound. Depending on the design, this can either be a single magnet or an array of magnets. Try this , take the driver out and lay it on the magnet , cone up. NEW: This symptom checker now includes the ability to select symptoms by body location. Irregular defects, such as voice coil rubbing in the gap, buzzing parts, loose particles, wire beating, hard limiting of the surround, bottoming of the voice coil former at the back plate, air noise in leaky enclosures, generate impulsive distortion which have not much energy but which generate a wide-band spectrum. The sub on the other speaker is silent when this is done. I've salvaged a couple of Peerless KO10DT soft dome tweeters which are a little worse for wear, but the voice coils are intact and apart from being dirty, the domes aren't too bad. You can push the cone in and feel it drag on the magnet is it's rubbib'. I took the woofer out and turned it 180degrees to see if this would help cure it and so far so good. Before you start cutting, make sure the template is level. Feb 2, 2016 · Now when gluing the spiders back to the basket, I did the best I could to make sure the spider and voice coil was centered. Low Sound or No Sound at All: The main result you will notice of a blown subwoofer is low sound or no sound at all coming from it. Press the tape firmly to create a tight fit. Or they may think of a solenoid for impact-type linear Apr 5, 2012 · hey -- we have a vintage 421 that has no low end. Most voice coil cooling happens from heat radiating to the colder magnet structure from the hot (200 to 300 degree) voice coil. The symptoms of those defects are more impulsive than the distortion of regular nonlinearities (e. A rubbing voice coil, buzzing loose part, hard limiting of voice coil former, loose particles in the gap and other loudspeaker defects cause signal distortion which are audible and have a high impact on perceived sound quality. When the magnets are repeatedly repelled and attracted, they move the coil back and forth quickly, kind of like the piston in an engine. Graphite has conductive properties so probably not a good idea unless you want to buy new drivers. guitar-pro. Parallel wiring of two 8-ohm voice coils will result in a 4-ohm overall impedance, while series wiring will result in a 16-ohm overall impedance. Are the woofers measuring the same or close to the same resistance. Apr 18, 2009 · Hiya folks, One of the midranges on my Wharfedale Dovedales seems to have developed a voicecoil rub, and i was wondering if anyone could advice me on how to fix this. 1 V/m/s. to no avail. Sensata delivers high-performance voice coil actuators designed to operate across wide temperature ranges and harsh environments, with custom options including moving magnet designs and more. The figure to the left illustrates the interpretation of the intermodulation distortion measurement using a fixed low frequency tone f 1 and a high frequency tone f 2 The figure to the left shows the intermodulation of a high frequency tone f 2 by a low frequency tone f 1 caused by a nonlinear force factor Bl(x) characteristic. Get In Touch. It plays fine for the most part but sometimes emits a rattling and/or piercing brief sound. When I pull the cone out, smooth. This coiled wire is attached to the cone or diaphragm of the speaker, and when an electric current passes through it, the coil moves back and forth. May 22, 2020 · It you re-install it in the cabinet (and remember which way it was oriented) try rotating it 180°. It can be averaged to 3. You want to go about half way between the dust cap and the frame, only pressing down on part of the cone. Lay the speaker magnet side dowonon the floor or a stable flat surface. Originally posted by leadfootdriver. Chris140wrote: I just got my JBL LX44's hooked up and ran them and Voice Coil Actuators. Aug 23, 2023 · The symptoms are a very loud hum/buzz whenever sound goes through it. I lolled when I read it but, hey, it's the less intrusive method so the first to try. Have basically narrowed this issue down to voice coil rub of some kind. e. It is a higher pitched sound. ---- The speaker is "cleaned" down to the magnet and frame and usually "rebuilt" exactly as originally "coned" at the factory. May 22, 2024 · The Best Tablature Editing Software:https://www. The size of the voice coil’s diameter affects how much power a speaker can handle. A loudspeaker voice coil is an essential component of a speaker system that helps to convert electrical signals into sound. It acts as the moving part of the motor. Oct 25, 2022 · If the rub is from a distorted voice coil or a bent former from over excursion and bottoming out then maybe more repair is going to be necessary. Based on what I've read, my best guess is that the voice coil is rubbing as a result of gravity. If so, probably okay to leave alone. Yet, it sounds fine when i press down gently a corner of the cone. This one is used and has had the cone removed, hence it Hi-2. From the picture below, is this normal? Jan 12, 2018 · Today's video is about one thing to look out for when buying speakers, especially ones that are older or vintage, and that's Coil Rub. Oct 26, 2023 · Voice Coil: This is a wound coil of wire designed to produce a magnetic field when electric current is applied. If the dust cap is already removed, visual inspection will indicate where the "rub" is occurring and the gap can be restored by manipulating the former away from the magnet assemblywith whatever tool you can find to Oct 29, 2009 · It turned to be voice coil rub. Feb 19, 2020 · The coil then scrapes against the top plate and is one major cause of failure. I think this is called a voice coil rub. Feb 27, 2010 · Pull the speakers, lay them on their magnets with the cone facing you. Feb 9, 2009 · I might finally refoam my first speakers soon. Annoying distortion from one of subs on the new-to-me HK-40s. You can sometimes hear a loose coil or coil rub using this method. When designers need a modest amount of motion and power, they naturally think of a motor. Oct 8, 2010 · Super Member. The guy must not have shimmed them. The first speaker went great with no issues. I was just wondering how much voice coil rub would it take to damage the voice coil? The speaker was under warranty so it is being repaired at the moment. I will receive a small kickback if you purchase)My guitar sp Dec 15, 2012 · I strongly advise you to get a whole new driver from JBL If it is no longer available, they can probably supply a suitable replacement, but if that is the case you will have to replace the same thing on both speakers to have matching performance. Dec 3, 2017 · Great post! I might add that another way to test for loose or misaligned voice coils is to tap the magnet from behind with your hand and put your ear close to the center of the cone. Thanks to everybody for the contributions and ideas. First, check for any visible damage to the subwoofer itself, as this can be an indication of a problem with the voice coil. Finding a spare driver on the used market or the whole speaker, might be a better deal in the long run. Call Us On : 011 334-4158 Or Visit Us At Unit A1, 51 Rosettenville Road Village Main Johannesburg 2001 GPS CO-ORDINATES: LAT: -26°12'57. JBL gaps are small compared to most and as a result any small particles can and will cause rubs. Defects are also caused by systematic errors in loudspeaker design which impair the robustness of the product and make a malfunction at a later time more likely. 1. g. Depending on who does the repair, the parts that get replaced may vary. If I push the cone down when no sound is passing through, and it starts to rub, the slight hum almost goes away. However out of a round voice coil former can be the culprit. Nov 17, 2023 · I use these speakers just about daily and tonight for the first time I noticed some buzz/distortion in the low end on one of the speakers, particularly apparent at low volumes. Here are some pictures Before May 23, 2020 · Issue 1: Coil rub. Talk to a JBL engineer about it. The sound should be a clear thud. I've recently purchased a pair of the older 600w Fane 18XBs, and both of the voice coils are slightly rubbing, one worse than the other and the sound is noticeable even at low volumes. Never had bad speakers so I don't don't know what a rubbing voice coil will sound or feel like. If the misalignment is really bad, it can rub at low drive levels also. Take the speaker out of the box. There is a way to correct that if it isn't too severe. That makes sense since there’s often a brushed, brushless, or stepper motor that can meet the objectives, sometimes with some necessary add-on gearing. Next, apply the protective tape over the voice coil gap, ensuring it completely covers the area where the voice coil is located. So I trained them to play at a volume that they were happy with I then very slowly went higher and higher with volume and Oct 6, 2005 · David, congratulations on the purchase. When an ignition coil goes bad, the Check Engine Light comes on, either solid or flashing. Make sure it fully covers the exposed magnet surface. The cone "whooshes" and is definitely rubbing when gently pressed. May 10, 2011 · In this paper, the wear of the suspensions in a speaker. Figure 8 - Back emf results. The benefits of voice coils include their simple design and easy construction process. Central Maine. Voice coils play a significant role in sound production, with their size impacting the overall sound quality. A larger voice coil can handle more power. Here is an image of what an actual loudspeaker voice coil looks like. If it's doin' it under load, the basket may be tweeked a bit out of shape, like maybe you have one side tightened down more than anywhere else. Oh my, it worled so well. Aug 7, 2017. or anything low freq. The name “voice coil” comes from one of its historically first Voice coil actuators are a type of direct drive mechanism that provides extremely precise positioning over small displacements. 2. When I push in on the cone I can feel voice coil rub on both, but only notice an audible rub on one. Your symptoms are characteristic of burned voice coils. This is basic and I won't go into it here, but the rule is that the value should be less than the expected nominal Impedance rating ( with some, especially older, speakers it may be just barely below the Mar 23, 2023 · In most cases, the blown speaker will have loose or damaged voice coils. bm mu gh wq jf qo qx mz or ri