getech Posted October 9, 2006 Author Share Posted October 9, 2006 Inorder to understand how the Sunfire amplifier works, it would behelpful to review a conventional amplifier and illustrate some of thevery difficult engineering problems associated with powerful and veryhigh current amplifiers. As you know, a conventional amplifier has apower supply, and for a 300 watt amplifier the power supply voltage isapproximately 90 volts. That 90 volts is parked way up in the sky at 90volts above ground zero. The audio signal varies under that voltage andas long as the amplitude of the audio signal remains below 90 volts,the amp will not clip or run out of power.As an example, assume the output voltage at the loudspeaker is 30volts, and10 amperes of current are flowing. The current starts at thepower supply and flows through the transistors; as it goes through thetransistors it makes them get hot. How hot? The measure of hotness ispower; voltage becomes amperage. Remember, there are 10 amperes flowingand if there are 30 volts on the loudspeaker and there is a 90 voltpower supply, that means there are 60 volts across the transistors.Again, the power is equal to volts times amps -- 60 volts times 10 ampsequals 600 watts! That is not the power going to the load, that's thepower going into the transistors as heat and must be gotten rid of.Hence, the transistors are mounted on a large heat sink; the heat istransferred to the heat sink and ultimately to the atmosphere. Now, since the amplifier is only about 20% to 30% efficient, a lot morepower has to go into the amplifier than comes out because 600 watts isgoing up in heat. Since it's inefficient, there must be lots of outputtransistors, lots of heat sink, and the power supply has to be muchlarger than would ordinarily be required in order to make up for allthe power that's being wasted. Instead of a 30 pound power supply, ithas to be 80 pounds. Well, so what? It's not difficult to add the powersupply and heat sink necessary to allow the amplifier to deliver thepower. However, a problem that is very insidious exists! The problem is this. The output transistors that amplifier designersuse are big 20 ampere output transistors. I use them, they are used insmall amplifiers and large amplifiers. They are used in high endamplifiers and are even used in most of the big receivers these days.It's a standard part in our industry. It's the big Motorola, Toshibathe Sanyo or Sony equivalent. This transistor is rated at 20 amperes.However, it's only able to deliver 20 amperes if there are 10 volts orless across it. That's because it's a 200 watt part and can neverdissipate more than 200 watts or its rating is exceeded. At 50 volts for example, it can deliver only 4 amperes, because 4 times50 is 200. At 90 volts it can deliver only 2.2 amperes. Going back tothe earlier example with 60 volts across it, it can deliver only 3.3amperes. Not very much current. If a designer wants to have anamplifier that's able to deliver lots of current into very lowimpedance loads, to deliver current in an unvarying way, no matter howdifficult the loudspeaker impedance, no matter what the phase angle, heor she must use many paralleled output transistors -- lots and lots ofthem. Remember, they are not good for 20 amperes, they are really onlygood for a small portion of that, especially when driving low impedanceloads. Consequently, a designer has to parallel many, many output transistors.He or she must mount these transistors on huge heat sinks, and, becausethe amplifier is not very efficient it must have a huge power supply.Since each transistor draws its own idling current, the amplifier tendsto run hot when it is just sitting there at idle. Biasing issues becomevery severe problems. To this day, solutions are still being sought.For example, Nelson Pass uses the sliding biasing circuit, and Krelluses a four-tiered switchable dynamic biasing circuit. Engineers anddesigners forever fret over whether they're going to bias theiramplifiers Class A, or Class AB, or use a sliding bias scheme. Bigproblem. Still, amplifiers that can deliver these awesome and majesticcurrents do exist, but to get there you have to reach up to the bigMark Levinson's, Thresholds, the big Jeff Roland's, even the massiveKrell's. Those amplifiers can deliver the performance, but they arevery expensive -- starting at about $8,000. There is a better way.THE TRACKING DOWNCONVERTER Inthe Sunfire amplifier, that 90 volt power supply voltage that Imentioned earlier is removed from being parked 90 volts above ground,and is brought down and parked at only 6 volts above ground. The 90volts no longer exists. Then, at any moment in time, regardless of whatthe output of the amplifier is, that power supply voltage will alwaysbe 6 volts above the output signal. If the output signal is zero, theoutput of the Tracking Downconverter will be 6 volts. If the output ofthe power amplifier is 30 volts, as in the previous example, the outputof the Tracking Downconverter will be 36 volts. The voltage across thetransistors remains a constant, unvarying 6 volts. Therein lies thebeauty of the Tracking Downconverter. Now, consider the previous example. The amplifier was delivering 30volts to the load and10 amperes of current were flowing. That exampleresulted in 600 watts of power in the output transistors. In theSunfire amplifier, that same 10 amperes is not dropping across 60volts. Instead, it's dropping across 6 volts so the power is only 6volts times 10 amps -- 60 watts wasted rather than 600 watts. Ten timesless -- an order of magnitude less. It's so little power that theamplifier does not have a heat sink; it doesn't need one. There is nota heat sink to be seen in this amplifier, yet it can deliver well over2,000 watts into 1 ohm. And because of its increased efficiency, thepower supply doesn't have to weigh 80 pounds. The power supply can be areasonable 30 pounds. But here's the best part! Remember that a 20 ampere transistor can onlydeliver the full 20 amperes if there are 10 volts or less across it(because of its 200 watt limit). In the Sunfire, since there are only 6volts across the transistors at all times, the full output current of20 amperes can be delivered from each output transistor instead of 2, 3or 4 amperes as in a conventional amplifier. Because each outputtransistor can deliver its full 20 amperes, the amp can deliver lotsand lots of current into low impedance loads. In the Sunfire I used 12output transistors per channel, each capable of 20 amperes; thatrepresents a peak to peak output current of over 240 amperes. And itcan do so into varnishing low load impedances. That's a staggeringamount of current. That's what is required to have an amplifier withthe performance of a $10,000 machine.THE UNCANNY TRACKING DOWNCONVERTER AND A TRULY REMARKABLE FACT A remarkable feature of the Tracking Downconverter is its intrinsic and unique ability to transform high voltage and low current to low voltage and high current. For example, if the input power to the downconverter is being delivered at a very high voltage, the output power can be delivered at a very high current. The transformation ratio; i.e., how much the current is increased, is in the same proportion that the voltage is decreased. In the case of the Sunfire, the power supply voltage is 2 times 125 volts, approximately 250 volts. Therefore, if the input current is 10 amperes and the output voltage is 25 volts; corresponding to a difficult or low load impedance; the output current will be 100 amperes because 250 divided by 25 is10. (The input current 10 amperes multiplied at the output by 10 for 100 amperes. A conventional amp could never do that, i.e. 10 amps in equals 10 amps out.) . It's this remarkable property of a Tracking Downconverter that allows the amplifier to deliver tons of current into vanishing low load impedances. It is also the property that allows the amp to run cold, to have a smaller power supply than would conventionally be required, and to possess a very flat output voltage characteristic. Whenever the load impedance is halved, the power just continuously doubles. A scientist would say "load invariant". Have you ever lusted for a $7,000 - $20,000 Mark Levinson, Roland, Krell, or Boulder amplifier?At that point in the design, the Sunfire was an amplifier that coulddeliver almost limitless current, almost limitless voltage and deliverboth simultaneously for tremendous output power, and runs cold.However, the design is not yet complete. The amplifier needs to belistened to. Listening to an amplifier in its design process ispotentially the most time consuming, and is where the art of amplifierdesign enters the picture. When I listen, I first use a female vocalistand make certain that she can be accurately located in an acousticspace between the speakers and in such a way that a believable halo ofspace surrounds her, and she becomes palpably three dimensional. Also,I want her voice to be soft, musical, lyrical and have a great deal ofbelievability. After the female voice, I listen to the male voice usingbaritones for the chestiness in the human male voice. When that part ofthe work is completed, I go to the symphony. I have in my head atemplate of what a symphony orchestra should sound like. I close myeyes and fit the sound of that symphony orchestra in my head, to thesound that my amplifier is making through the loudspeakers. In the caseof the Sunfire, since human voice reproduction was so stunning, I foundthat the symphony orchestra locked in and I didn't have to do anything--- sort of like getting flesh tones correct on a color televisionreceiver, all the other colors often lock in with very little effort.Getting the flesh tones correct is the most difficult process ofdesigning a color set. But I digress. This effort was because I wanteda totally accurate amplifier. CURRENT SOURCE - VOLTAGE SOURCE Atthat point I had an amplifier that was tremendous -- lots of current,lots of voltage, incredible performance and then I added a uniquefeature: A choice of outputs -- voltage source output and currentsource output. Let me explain. A transistor is inherently a voltagesource device; whenever an amplifier designer designs an amplifier withtransistors, the result is a solid state amp that will typically have avery low output impedance approaching zero. A vacuum tube, on the otherhand, is intrinsically a current source device. If an amplifierdesigner builds an amplifier out of vacuum tubes, he or she typicallyends up with an amplifier that has a current source outputcharacteristic, i.e., a higher output impedance. It's this high outputimpedance that is primarily responsible for at least 80% to 90% of whatmakes a vacuum tube amplifier sound like a vacuum tube amplifier -- aglow to the midrange, a soft high end, typically a layered stage depthand an open sound stage that is wider than it would be with a solidstate amplifier. This musical presentation is very sumptuous and lovelyto listen to, is quite captivating and the main reason many people lovevacuum tube amplifiers. Now, back to the Sunfire. Sunfire has two sets of output terminals onthe back. One is a voltage source output with very low impedance. Theother is a current source output with a higher impedance (currentsource) output characteristic. The choice of which to use is up to you.If you wish a solid state kind of sound, use the voltage source outputterminals. If you want the vacuum tube sound, use the current sourceoutput terminals. Or, and this is the best part, you can bi-wire yourspeakers. Use the voltage source to the woofer, and wire the currentsource to the upper range of the system. That way you have the tightslam impact bass that a solid state amplifier can deliver, and you havethe glow to the midrange, the sumptuous sound stage, and soft,delicately detailed highs that current source amplifiers typicallydeliver, i.e., vacuum tube amplifiers. The best of both worlds --Again, when wired that way, you have tight bass, a beautiful soundstage, a sumptuous high end and a very believable sense of layereddepth to the sound stage that is simply not available from a solidstate amplifier. (At least from normal output impedance solid stateamplifiers.)SUNFIRE CIRCUIT DESCRIPTION, AMPLIFIER SECTION Theinput stage is a low noise FET operational amplifier operated in aforced Class A single ended mode. The output of this stage drivesbalanced Class A level shifters and a balanced Class A voltage stagethat swings the full rail of 250 volts peak to peak. The remainder ofthe current gain stages run full balanced with a constant VCE of 6volts to the loudspeaker. It is heavily biased into the Class A regionfor small signals and Class AB region for large signals. Since thepower dissipation in the output stages under simple quiescent biasconditions is 15 times less than a regular amplifier for the sameoutput power, much more idle current can be used. The issue of how tobias this amplifier becomes moot -- all but irrelevant. All of thebiasing issues simply evaporate because of the 6 volts. Even though ithas a vacuum tube output characteristic on the current source outputterminals, there is not a vacuum tube inside at all -- except for themeter pilot lamp, it's fully solid state.THE UNCANNY TRACKING DOWNCONVERTER Comingin from the outside world, we find a conventional main power supply; alarge power transformer and filter capacitors. The output of this powersupply feeds the Tracking Downconverter. The output of the TrackingDownconverter is fully regulated and tracks the audio, receiving itsinput signal from the same signal that drives the main amplifier.Essentially, the Tracking Downconverter is another power amplifierbecause its output voltage is in synchronism with, and tracks the audiosignal, always above it a constant 6 volts. The input to thedownconverter is a small signal Class A Motorola transistor. The outputof this transistor drives a Texas Instrument PWM digital comparator.The output of the comparator drives a Hewlett Packard precisionoptocoupler which level shifts the digital control pulses to the gatesof 12 International Rectifier Hexfets. The final output is smoothedinto a continuously varying tracking voltage by the main energy storagedownconverter inductor wound with humongous #12 wire on a low lossnon-saturating ferrite inductor. The final energy storage capacitor isa 6.8 microfarad low ESR unit, and 12 dB of feedback is taken from thiscapacitor to the input stage. Finally, a Shotky free wheeling diodeprovides the energy return path for the Hexfet side of thedownconverter inductor.SIDE BAR Manyamplifier testers will operate an amplifier into an essentially deadshort circuit and give it a pulse of 500 microseconds or 20microseconds or even one-thousandth of a second and measure the outputcurrent. This test is only a parlor trick since the output current canbe very large, but since the load impedance is zero, and power is Isquared R, no matter how large the current, the output power is zero.It is a parlor trick. The amplifier could never sustain those hugecurrents for more than a few hundred microseconds because if it did,the transistors would blow up.Take a conventional amplifier and do such a test with it and you canhave incredibly high currents for a few hundred microseconds, but notfor long. The amplifier would blow up because for the high voltagesthat exist across the transistors during that moment in time, thetransistors are rated for only a few amperes (not tens or hundreds ofamperes). However, this test does tell the amplifier tester a lot aboutthe protection circuits. A skilled tester can determine whether theamplifier has current limiters or power-fold back protection circuits,or whether it doesn't have any protection circuits at all and relies onfuses alone. It does not tell anything about how much useful currentthe amplifier can deliver. A conventional amplifier may deliver 60amperes or more for 100 microseconds but could not, under thoseconditions, ever deliver more than 8 amperes of current for longer thanthat. Not exactly a high current amplifier. Again, it tells ussomething about the action of the protection circuits, but not aboutthe current capability of the amplifier. By comparison, the Sunfirecould deliver those huge currents all day long -- far longer than a fewhundred microseconds.SUNFIRE, PUTTING IT ALL TOGETHER 1) Full output current from each transistor is always available up to 20 amperes per transistor. 2) Massive output current is available even at low output impedances. 3) Heat sinks are not required. 4) Power continuously doubles down to below 1 ohm. 5)Most of the input power goes to the load, therefore, the power supplycan weigh 30 pounds instead of 80 pounds. The amplifier can supplyhumongous current, massive output power, tremendous voltage, runs cool,and is very efficient. 6) Only 12 output transistors are needed per channel for peak-to-peak current of 240 amps. 7) Bias current and idling current issues become irrelevant and nonproblematic. 8)The Tracking Downconverter multiplies current in the same ratio thatthe output voltage is reduced and it does so automatically by itsintrinsic nature. 9)At high impedances, it delivers high voltage and high current. At lowimpedances or difficult impedances, it delivers even more current,delivering awesome and difficult to believe amounts. 10)When biwired, Sunfire delivers incredible bass whack and a huge threedimensional sound stage with detail retrieval so stunning that you willoften hear musicians breathing. 11) Costs far less than any other amplifier in the world that hasSunfire's performance. All because of science and the uncanny TrackingDownconverter. MY PERSONAL BELIEF SYSTEM REGARDING AMPLIFIER DESIGN Myphilosophy regarding amplifier design is embodied in this new Sunfireamplifier. The amplifier speaks for itself, but I would like to addresssome of the details:INTEGRATED CIRCUIT OPERATIONAL AMPLIFIERS -- Inthe past, monolithic integrated circuit operational amplifiers (opamps) have received a bad rap for use in audio circuits, and for goodreason. My experience has been that if a sampling of op amps, all fromthe same manufacturer, and all the same number, are tested, one findsthat about one in fifteen will exhibit some crossover notch distortion.The reason for this is that most op amps operate with a Class AB outputstage, but they do not have a control for adjusting the idling current.Since an op amp is subject to the same limitations that a big amplifieris, some of the units will exhibit large crossover notch distortion,most will exhibit none, and a few of them will actually run slightlywarmer than intended. In high speed mass production the op amp idlingcurrent is set by the design of the circuit, but it does not come withan adjustment to allow for variations in idling current. This problemmay be completely eliminated by operating op amps in what's known asforced Class A operation. This is very easy to do. All that is requiredis a current source or a simple pull up resistor installed at theoutput of the amplifier. This forces one transistor to be always offand the other transistor to be continuously operating as a single endedClass A output device. As long as the op amp is operated within the newcurrent source limit, the output will be totally free of crossovernotch distortion. The practical result is that any family of op ampscan be used with absolute assurance that all of them, time after timeagain, will not have crossover non-linearities. In the past, this problem has given op amps a very bad name for use inaudio circuits and, from my perspective, unnecessarily so. Yet, as youcan see, not without good reason. In my designs, whenever I use an opamp, I always use a current source at its output. The choice of whetherto use an op amp or to use discrete components is a matter ofapplication. For example, for low distortion small signal requirements,an op amp is definitely the way to go. Normally, an op amp will havebetter power supply rejection and will be far more linear. In the caseof FET input amplifiers, vanishing low offset voltages and greatimmunity to input rectification accrue. Slew rates can be as high as weplease and distortion as low as we please, depending on the choice ofop amps. However, in other applications, for example, one with largesignal swings, a discrete circuit is best when higher current isrequired than is normally available from integrated circuit op amps. In conclusion, for a small signal amplifier operating on plus and minus15 volts, I would always chose a good op amp. I would never build adiscrete one unless I had a very special application, i.e. high currentor high voltage output.DISCRETE CIRCUITS Idesign with discrete circuits whenever I have complex feedback issues,or when I have complex signal processing issues in which controlvoltages must be developed for muting circuits, protection circuits, ordynamic control circuits as in a prologic decoder and, of course, inthe output stages and driver stages of high power, high current audioamplifiers.CAPACITORS Iprefer to use film capacitors for coupling capacitors and to useelectrolytic and/or film capacitors in bypass applications. I prefer touse ceramic capacitors in high frequency feedback systems and forcertain high frequency bypass applications. I use electrolytics forenergy storage and will use an electrolytic capacitor as a couplingcapacitor provided that under no condition is the voltage across thecapacitor allowed to vary at all. This means that a very large couplingcapacitor has to be used at the lowest frequency of interest and itmust be approximately 100 times larger than normally required. Hence,an electrolytic can't be used in a filter circuit or critical timingcircuit. In that case I would use either a film capacitor or aprecision ceramic capacitor.Further, I believe that ceramic capacitors are best for high frequencystabilization in feedback loops, and the use of film capacitors in thatapplication is something that relatively inexperienced designers do,and for the most part I consider to be a fad having essentially zeroscientific substance. When you examine a circuit that I design, youwill find a mixture of electrolytic capacitors, ceramic capacitorstantalum capacitors, film capacitors, low ESR film capacitors, and highcurrent capacitors, depending on the particular application. Each typeof capacitor has its advantages and disadvantages when used in anyparticular circuit. The choices you will see in my circuit designs arethe ones that I believe yield the best results and the best sound.OUTPUT TRANSISTORS - BIPOLAR OR MOSFET Ibelieve that the output stage of a power amplifier is best served bydesigning and building it with bipolar transistors simply becausebipolar transistors are more linear, can deliver more current, and willtypically have better SOA (Safe Operating Area) specifications forsimultaneous voltage and current when compared to an equivalent mosfet.If a very high performing amplifier is desired, bipolar transistors arethe exclusive way to go and you can see this by simply surveying theamplifiers on the market. All the very expensive, very high current,high performing amplifiers in the $8,000, $10,000, $15,000 price rangeuse bipolar transistors. Not one is designed using mosfets. Bipolarsare best in audio output stages. The use of mosfets in audio outputstages, again, is basically in my opinion, a fad. Excellent results, ofcourse, can be obtained in lower priced, lower powered amplifiers usingmosfets.MOSFETS OR HEXFETS(Brand name of International Rectifier mosfets) Idesign high power clocking circuits using mosfets because that's wheretheir advantage lies. If a device is going to be on or off, then amosfet is definitely the way to go because Safe Operating Areaconsiderations are not an issue, and their high speed and lack ofstorage time can yield incredible efficiencies. In those applicationsthey are extremely rugged -- far more rugged than bipolar transistors-- just the opposite of when used as a linear output device, in whichcase bipolars are more rugged than mosfets. To summarize, I use bipolars for linear operation, and mosfets indigital applications. Given the choice, I would never do otherwise.(Given the best of both devices currently available.)PRECISION PARTS Mychoice of using precision parts is based on my scientific view of theworld. It's not based on myth or fads. For example, in my Sunfire, Iuse the fastest, lowest transition time, highest precision digitalcomparator on the face of the earth. That is a Hewlett PackardHCPL-2611 because the circuit performs best when using the bestprecision available. In the case of circuit performance, I ordinarilyuse 1% precision resistors because by using 1% resistors, assembly andmanufacturing efficiencies are vastly increased because provisions foradjusting the circuit to come into specifications are not required.Each circuit works the same as the previous circuit time after timeafter time in a manufacturing environment.FALSE BELIEFS Ithink that false beliefs, especially in audio, have given rise to somereally wild designs, for example, $25,000 nine watt audio amplifiers.You will never find me designing such equipment -- I simply do notbelieve in it. However, I love to read about such designs, and I loveto think and talk about them. I'm overjoyed there are people in thisworld who do design amplifiers like that. It's part of what makes audioso much fun. Quote Link to comment Share on other sites More sharing options...
TheEAR Posted October 9, 2006 Share Posted October 9, 2006 getech, Man that is a great CUT COPY AND PASTE ! Quote Link to comment Share on other sites More sharing options...
getech Posted October 9, 2006 Author Share Posted October 9, 2006 gee, thanks ear...nice to see you are on top of things! Quote Link to comment Share on other sites More sharing options...
mas Posted October 9, 2006 Share Posted October 9, 2006 Its nice to hear that Bob Carver "prefer(s) to use film capacitors for coupling capacitors and to use electrolytic and/or film capacitors in bypass applications" as well as being a SET fan(not)! [] On the other hand, John Meyer occassionally (hey, its bound to happen! ...its just a matter of probability!) comes up with an idea regarding meaningful amplifier ratings that has some merit: http://www.meyersound.com/support/papers/amp_power.htm Quote Link to comment Share on other sites More sharing options...
TheEAR Posted October 11, 2006 Share Posted October 11, 2006 Just in,my low end Sunfire D-8 just died today! After a giant 20 minutes of operation last night,I switched the sub off.Today nothing,no function light! All fuses good,both back and the two inside! The transformer looks like a major POS(very much the culprit here,blackened winding!). Why is Bob switching to this POS amp,is beyond me.The older transformerless Sunfire subs all work A1,this one (the D-8) dies after 20 minutes! LOL I am bringing the amp to the store for an exchange.What a lemon.Now you know,even SUnfire subs(the cheap ones D series) can die. My Signature,Mark II and Super Junior never had any problems,even after blasting them full tilt and years of use! This isn the first product I have that dies after so little time.Well I will not strat crying like in the LoudMedia ssecion.Lemons are a part of life,I AM FUMING MAD now...at least I have my dozens of subs to continue pumping the subsonics. getech, Ask Bob to demand forgivness for this incident.I want a compensation...a FREE Sunfire keychain. [] Quote Link to comment Share on other sites More sharing options...
Paul Posted October 13, 2006 Share Posted October 13, 2006 Just in,my low end Sunfire D-8 just died today! After a giant 20 minutes of operation last night,I switched the sub off.Today nothing,no function light! All fuses good,both back and the two inside! The transformer looks like a major POS(very much the culprit here,blackened winding!). Why is Bob switching to this POS amp,is beyond me.The older transformerless Sunfire subs all work A1,this one (the D-8) dies after 20 minutes! LOL I am bringing the amp to the store for an exchange.What a lemon.Now you know,even SUnfire subs(the cheap ones D series) can die. My Signature,Mark II and Super Junior never had any problems,even after blasting them full tilt and years of use! This isn the first product I have that dies after so little time.Well I will not strat crying like in the LoudMedia ssecion.Lemons are a part of life,I AM FUMING MAD now...at least I have my dozens of subs to continue pumping the subsonics. getech, Ask Bob to demand forgivness for this incident.I want a compensation...a FREE Sunfire keychain. [] Some day some one will think of installing 120mil computer fans to cool the insides,Well Let it be me[] diy. Quote Link to comment Share on other sites More sharing options...
getech Posted October 13, 2006 Author Share Posted October 13, 2006 Ear, sorry about your D-8...that should not have happened but I am sure they will take care of you...if not let me know. I'D LOVE A SUNFIRE KEYCHAIN MYSELF. How about a Sunfire brochure instead? Quote Link to comment Share on other sites More sharing options...
TheEAR Posted October 13, 2006 Share Posted October 13, 2006 Ear, sorry about your D-8...that should not have happened but I am sure they will take care of you...if not let me know. I'D LOVE A SUNFIRE KEYCHAIN MYSELF. How about a Sunfire brochure instead? Well guess what? It was the POWER SWITCH! I replaced my amp,a little switch! Now works fine. Thanks for the help,I think you would install a special amp that would take TheEAR out cold. [] OH OH OH I have to post some funny pic,all three in a pyramid,like my RSW's. He comming down this way in a few minutes. [] The D12 is a very nice inexpensive sub,like the D8 and D10 it is both very tight,controlled and is more about bass definition than fake bloated boom.Bob Carver has another hit,will please many people seeking very compact subs. Not to be mistaken with petty bass modules that add moer distortion they add bass.These are very clean and distortion only starts to raise in any significant way when you drop doan to the extension limits of these subs. Make sure to use a double sided tape to fix them in place,sound better and will have more impact.All my small Velodyne and Sunfire subs are taped(double side security stickers)to the floor(hardwood flooring). Quote Link to comment Share on other sites More sharing options...
TheEAR Posted October 14, 2006 Share Posted October 14, 2006 All sealed,8",10" and 12" woofers. Quote Link to comment Share on other sites More sharing options...
Paul Posted October 14, 2006 Share Posted October 14, 2006 Ear, sorry about your D-8...that should not have happened but I am sure they will take care of you...if not let me know. I'D LOVE A SUNFIRE KEYCHAIN MYSELF. How about a Sunfire brochure instead? Ok you wanted a brochure here you go....[] Quote Link to comment Share on other sites More sharing options...
Paul Posted October 14, 2006 Share Posted October 14, 2006 Ear, sorry about your D-8...that should not have happened but I am sure they will take care of you...if not let me know. I'D LOVE A SUNFIRE KEYCHAIN MYSELF. How about a Sunfire brochure instead? Ok you wanted a brochure here you go....[] Quote Link to comment Share on other sites More sharing options...
Paul Posted October 14, 2006 Share Posted October 14, 2006 Ear, sorry about your D-8...that should not have happened but I am sure they will take care of you...if not let me know. I'D LOVE A SUNFIRE KEYCHAIN MYSELF. How about a Sunfire brochure instead? Ok you wanted a brochure here you go,The front looks nice[] Quote Link to comment Share on other sites More sharing options...
TheEAR Posted October 14, 2006 Share Posted October 14, 2006 This is just great Paul,seriously.I never,EVER saw this brochure. [:@] Quote Link to comment Share on other sites More sharing options...
Paul Posted October 14, 2006 Share Posted October 14, 2006 This is just great Paul,seriously.I never,EVER saw this brochure. [:@]This was not for you Ear it was for getech, I thought he asked for one [*-)],I know you have boxs full of them[] Quote Link to comment Share on other sites More sharing options...
TheEAR Posted October 15, 2006 Share Posted October 15, 2006 Yes I have,had all the subs in the Sunfire book...[] Bob Carver designs great audio gear. Quote Link to comment Share on other sites More sharing options...
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