Testing subwoofer driver with servo

Thanks to its patented direct servo system, the f12g has numerous settings which allow the end user to tailor the sound to their own tastes or to blend better in their own setup. A leading name dating back to home theaters beginnings two decades ago, the silicon valley firm recently launched its new flagship series, digital drive dd, to replace the longestablished high gain servo hgs line. Sep 04, 2001 given the much higher cost of a velodyne 18inch, and the fact that two servo 15as will outperform one velo 18 in maximum output and distortion, it may make sense for those seeking sota bass to buy two servo 15s, which will also give better flexibility in room placement, allow for stereo bass if your system permits, and obtain a better lock. It was a lot of fun, and all the subwoofers did quite well. Im going to have to somehow probe the amps output and listen for the noise from two places at the same time. Aes elibrary a high efficiency servomotor driven subwoofer.

One of the main reasons for this is that the driver is out of control. These amps are designed to do it all when matched with the appropriate subwoofer enclosure and loudspeaker driver. Cm one of the more wellknown proponents and manufacturers of accelerometerbased servosubwoofer systems addresses this, i believe, by incorporating limiting circuits to protect the driver, though it has been said that this may in some circumstances limit dynamic performance. Question about testing a servo amplifier i have 3 sem mts30h44 dc brush motors paired with 3 servo dynamic amplifiers. Its 8inch cone driver with advanced yamaha active servo technology ii works with optimized impedance for a more stable, tighter bass response. Subwoofer speakers vary by application, output, and methods of construction. Servodrive contrabass back in 1987, servodrives beltdriven contrabass subwoofer seemed to rumble onto the market out of nowhere. This is telling because, simply put, if you start with. It does look like the ideal test driver for what you are doing. Please note, it is recommended that you use aa0501 plate amp updated july 2008 new recommended amp. These are the same drivers and servo amp used by clayton shaw of spatial. By doing so, however, we limit ourselves from some very happening new equipment.

What is a servo subwoofer audioholics home theater forums. Apr 27, 20 the key here is the relationship between 2nd and 3rd order and that theyre well separated, indicating no serious flaws in the driver. Compared to the hgs18, the dd18 boasts a more robust. This unit represents the continued refinement of velodynes top subwoofer platform and follows the familiar velodyne formula for success. Mar 22, 2014 contrabass is the model the only option i can think of is to pull the servo guts and mount standard 15s in all 4 locations. Please note, it is recommended that you use aa0501 plate amp. Velodyne dd18 with only slight exaggeration, velodynes dd18 could be called the first subwoofer with a college education. And despite some compression occurring at the very deepest frequencies, the servo15 still remained linear to 110 db at 35 hz at the highest sweep level, which is quite impressive. The key here is the relationship between 2nd and 3rd order and that theyre well separated, indicating no serious flaws in the driver. Trying to resurrect an early 90s motor driven subwoofe. While our drivers are better than most, their performance in a conventional subwoofer will never be as good as a direct servo subwoofer.

I was just wondering if you guys know of any downsides to servo subwoofers like the rythmik line by ascend acoustics. Back in 1987, servodrives beltdriven contrabass subwoofer seemed to. A lowfrequency transducer system, designated as servodrive loudspeaker for use below 100 hz is described. Diy 15 rythmik audio direct servo sealed subwoofer build. The transducer has a small voltage feedback coil to provide the servo input, and there is also a small value resistor in series with the woofers driven coil which is monitored across to provide another input to the servo. Trying to resurrect an early 90s motor driven subwoofer, details here. It can correct for some driver nonlinearities to some extent. Cm one of the more wellknown proponents and manufacturers of accelerometerbased servo subwoofer systems addresses this, i believe, by incorporating limiting circuits to protect the driver, though it has been said that this may in some circumstances limit dynamic performance.

The servo feedback used in direct servo completes the loop, and the result is a degree of control and accuracy that is not possible using any other method. The rythmik fv15hp is a selfpowered frontloaded vented subwoofer featuring a custom 15 aluminumcone driver and 600 watt amplifier that utilizes a very unique servo feedback system for minimizing loudspeaker distortions, even at very high output levels where of course it is most important, since that is where subwoofers are quickest to reveal their failings. Hi all its time to start looking at some subwoofers for serious bass enthusiasts. The sw1204 sub was specifically for the discerning audiophile looking for the ultimate in accuracy and sound quality. His design goal was to make a subwoofer that would fit into a smaller space than most competitive subs. The nsw60216 tested in the standard 21 driver sealed cab. Sep 01, 2001 servodrive sound physics labs td1 speaker. Most people and audio pros are no exception have a tendency to stick with triedandtrue tools. This subwoofer also has three front ports directly below the driver.

Then see if the amplifier will stay on with no driver load connected to it. Use a volt ohm meter to determine if there is power to the servo drive at its disconnect. It is meant to be used with the direct servo plate amps. Global electronic services electronic equipment repair. Not sure about the exact mechanical motor deal used to produce the sound, but these days, the powerful subwoofer drivers available seem superior. Rythmik fv18 servo subwoofer sound demo report audioholics. The twisted flare port of this yamaha powered subwoofer reduces signal and airflow noise for bass accuracy.

Driver ds1510 15 high excursion with custom sensing coil driver materials black anodized aluminum with rubber surround cast aluminum basket copper flux modulation shorting rings amplifier 600 rms class h patented servo controlled dimensions 19w x 19 h x 20 d 2112 d with. But the unusual device, with its pair of belts looped around a rotaryshaft dc motor to drive opposing 15inch cones, had a literally fieldtested progenitor. The website seems to claim that they are superior in every way but of course you can never ask the barber if you need a haircut. Contrabass is the model the only option i can think of is to pull the servo guts and mount standard 15s in all 4 locations. Re room gain, in real life it obviously matters but it is 100% dependent on factors the subwoofer designer cannot control. What are the downsides of a servo subwoofer if any. Sw1204 speaker kits, loudspeaker design services, sub. Patented direct servo technology 600 watt class d hypex amplifier adjustable damping and minixlr input. Velodyne f1200b repair of servo circuit warning headphone users. Tom danleys intersonic servodrive subwoofers had an xmax of 12.

I have a velodyne dls 4000r subwoofer that is cutting out. No phd required in electronics or electroacoustics a servo woofer design can be. Subwoofer manufacturer rythmik audio has recently released three powerful new subwoofers that takes their vaunted direct servo technology to new extremes of power. You could hook up an old driver of some sort just to try and see if the amp will work without this accelerometer lead connected. Im not convinced driving it with a non servo amp is the best way to test the driver. Ive gone for the 1505 driver with the a370 peq3 amp from rythmik audio in texas.

Velodyne history 101 in 1983, david hall, the founder and chief engineer of velodyne acoustics, inc. The amplifiers are sourced from a manufacturer and then a daughter card added to implement the servo within the existing circuitry. The tapped horn subwoofer, is the next step in the evolution of the subwoofer. The critical q subwoofer a nonservo subwoofer design with servo performance. Why do most subwoofers fail to reproduce music accurately. A high efficiency servo motor driven subwoofer a lowfrequency transducer system, designated as servo drive loudspeaker for use below 100 hz is described. We have a 15 day standard turnaround time and free 2448 hour rush service with true load testing, full function testing and an 18month inservice warranty on every repair.

The bigger the driver, the more amplifier current and magnetic energy required to power and control the pistonic motion, and this current only gets you so far. My only thought is to find drivers with the lowest possible free air cone resonance. Direct servo is a patented technology that is far more effective than any other servo control systems of the past. The amp hums when the servo ribbon cable is not plugged in. Subwoofer drivers are likely to be found in their own dedicated subwoofer speaker system enclosure. Dual 8 audiophile direct servo subwoofer for audiophiles looking for uncompromising accuracy in both bass and the upper bass frequency range and for a higher crossover frequency up to 250hz, our f8 subwoofer is the ultimate choice. Ive been sold on servo subs since hearing one, but mine will be the first rythmik sub. Great features available on the subwoofer plate amplifiers at parts express can include auto onoff, high and low level inputs, balanced and unbalanced inputs, dsp, adjustable crossover frequency, and more. Passive subwoofers have a subwoofer driver and enclosure and they are powered by an external amplifier.

Given the much higher cost of a velodyne 18inch, and the fact that two servo 15as will outperform one velo 18 in maximum output and distortion, it may make sense for those seeking sota bass to buy two servo 15s, which will also give better flexibility in room placement, allow for stereo bass if your system permits, and obtain a better lock. Audio is direct source, sounded terrible on iphone mic. The pachyderm 6 was founder tom danleys answer to a request from cornell university for a subsubwoofer. The usual source of the feedback signal is a few turns of voice coil attached to the cone or a microchipbased accelerometer placed on the cone itself. In order to narrow down whether the amplifier or the subwoofer driver itself are the root cause, you must disconnect the subwoofers input leads inside of the enclosure, as well as the servo wires.

Modified the original design to be fully balanced throughout. For audiophiles and enthusiasts looking for uncompromising accuracy in an elegant package, the f12 signature edition subwoofer is the ultimate choice. The sub zone subwoofer testing rythmik audiogr research f12g direct servo subwoofer. Engineering challenges of big subwoofer drivers a subwoofer driver is only theoretical bass. Direct servo is a patented technology that dramatically reduces many different problems which prevent conventional subwoofers from reproducing accurately. Jan 31, 2016 in order to narrow down whether the amplifier or the subwoofer driver itself are the root cause, you must disconnect the subwoofer s input leads inside of the enclosure, as well as the servo wires.

Tom danley is rightly known for innovation in subwoofer design. Rythmik f12 direct servo subwoofer ascend acoustics. All servodrive loudspeakers incorporate a unique, patented operating principle involving the substitution of highspeed rotary servomotor and beltdrive system for the traditional loudspeaker voice coilmagnet transducer system. As far as i can tell, the manufacturer servodrive is long gone. The klippel will be used for loudspeaker and driver testing. Apr 28, 2017 the rythmik audio fv15hp subwoofer sports a 15. Dec 29, 2018 svs pb16ultra subwoofer 16inch driver, 1,500watts rms, dsp app control, sealed cabinet us s.

Rebuilt servodrive contrabass subwoofer test rob smith. Added a dc servo to ensure no dc offset reaches the tweeter my main system is a 100% dc coupled system. I have a velodyne dls 4000r subwoofer that is cutting out as. Svs pb16ultra subwoofer 16inch driver, 1,500watts rms, dsp app control, sealed cabinet us s. Test the circuit protection to make sure the voltage potential is within the specifications of the drive. Infinitys servostatik 1, which contains an 18 servo controlled separate subwoofer, was created in 1968 before ken had even met jonas miller in 1969. Paul explains how active servo woofers and speakers work. Loudspeakers servodrive speakers contrabass controlbooth. A subwoofer or sub is a loudspeaker designed to reproduce lowpitched audio frequencies. Testing a big subwoofer for max spl in your garage will get old for you, your belongings and house structure, and your neighbors pretty quick. I will be using my own klippel distortion analyzer and software modules to extract raw subwoofer driver data so we can assess the raw driver performance. It features direct servo to ensure accurate frequency and transient response, precise detail and extremely low distortion levels at even high output levels. The result is a driver capable of high spl and that is also accurate.

Servo woofers are rare these days and this questioner wants to know how they work, why more companies dont use them, and if ps audio. A servo based sub will have a driver with multiple voice coils. The result of this is an unprecedented power capacity, high efficiency, excellent linearity, and low distortion. I did see the analog servo sub thread that armand posted, and while a lot of that went over my head, the results in the tests he provided were. So what exactly was so special about the intersonic. Enrich your audio experience with clean bass details by using this 50w yamaha powered subwoofer. Andrew from axiom is pretty proud of the changes he made to the ep350. Reproduction of the very lowest frequencies contributes to a systems accuracy, as well as creating a visceral connection to the program material. All box subwoofers have serious problems with the sound waves from the rear of the driver seriously degrading definition. I was curious if anybody has measurements that show that a servo control loop on a subwoofer actually lowers distortion at frequencies in the 20hz50hz. Rythmik audio 15 servo subwoofer ds1500 custom installation subwoofer this decission was after a lot of researching and contacting owners who have had their subs for a while. Low distortion, dsp based high gain servo controlled woofer. Rythmik f8 direct servo subwoofer ascend acoustics.

Rebuilt servodrive contrabass subwoofer test youtube. Diy 15 rythmik audio direct servo sealed subwoofer. Powerful, rich, deep and solid with true 20hz extension is how i would describe the bass output of this sub. Svs pb2000 subwoofer black ash 12inch driver, 500watts rms, ported cabinet by svs only 11 left in stock order soon. One voice coil is hooked up to a correction circuit on the amp. The pachyderm 6 was founder tom danleys answer to a request from cornell university for a sub subwoofer. Rythmik audiogr research f12g direct servo subwoofer home. Sw1204 subwoofer raw driver test results small signal analysis. Feb 10, 2017 rebuilt servodrive contrabass subwoofer test rob smith.

The approach of adding a servo to compare the drivers movement continuously to the input signal has been used by many. It has a longer throw driver, stronger amp and tuning at about 27 hz, with typical in room response to 22 hz. While designed specifically for our direct servo subwoofers, all our drivers are also suitable for conventional use. It is going to be a real hitormiss in passive radiator cabinets. Yes it will likely have another pair of thin gauge wires with a connector that attaches to the driver for the accelerometer. F12g subwoofer testing thanks to its patented direct servo system, the f12g has numerous settings which allow the end user to tailor the sound to their own tastes or to blend better in their own setup. The truth behind active speakers and servo bass youtube. For audiophiles who desire the ultimate in accuracy, we recommend our direct servo subwoofers. The sub was very solid and produced a nice thud with the knuckle rap test. Global electronic services provides truly inhouse comprehensive repair services and solutions for most manufacturers as well as new, refurbished and obsolete equipment. This circuit can see the driver doing something it shouldnt and send a 2nd signal to the other voice coil correcting the abnormality. Im sure it would need to be the same test setup where the loop is turned off and on to. Rythmik audiogr research f12g direct servo subwoofer.

Mar 20, 2020 testing a big subwoofer for max spl in your garage will get old for you, your belongings and house structure, and your neighbors pretty quick. Velodyne hgs15 servo sub with distortion repair almost. Horn subwoofer the role of the subwoofer is simple. The source voltage will likely range from 210 volts to 480 volts, depending on the manufacturers drive specifications.