The Subwoofer SQL Revolution
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 726 Registered: May-05 | i just thought that i would take this time to expound on the relative importance of the past three-five years in subwoofer technology and performance (sounds like a magazine). i recall when SQL was the target for subs, but missed just short of a myth. it was either spl or sq. you had to choose. and even then, the standard for sq or spl was probably like the kicker comp of today at best. if you had a jl, then you had THE driver. everything else fell relatively short. and still then, the sq and spl subs had motors the size of bracelets. now, of course, magnet girth is far from the qualification for an accurate or powerful sub (the brahma could have equalled it's current performance with a considerably smaller motor. it just would have lacked appeal). i'm curious, though, weather or not XBL2 technology actually sparked the paradigm. or did another pave the way, and adire was the first to claim success? i recall ID trying three times before they got it right with the id maxx v3. |
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Gold Member Username: Jonathan_fGA USA Post Number: 4430 Registered: May-04 | Remember that in the 80s and early 90s, one of these subwoofers wouldn't be doing you any favors because regardless of their performance capability, amplifier power was EXPENSIVE. The musclecar era wouldn't have lasted during the gas crunch of the 70s and 80s, same goes with speakers and power, efficiency was the name of the game back then. XBL^2 didn't really start the revolution, though it contributed. Companies like JL Audio use a totally different topology from XBL^2 and it is still effective, they just have different pros and cons. There are applications that XBL^2 is good for and those that it isn't so great for. XBL^2 has a big advantage for a driver running sealed or infinite baffle, because of it's linearity and motor strength at higher excursions. Meanwhile, a driver used in a well tuned ported box could render having XBL^2 useless, possibly even as a drawback as in that application certain motor designs have more motor strength where it matters, which would equal a more parabolic BL curve, but one that has higher strength near the gap. Image Dynamics got it right with the V3, their problem was the fact that the subwoofer was used for high SPL applications, and the subwoofer uses a VERY tight gap. With the narrow surround, this posed problems as the sub exited it's linear region, and voice coil scraping was an issue with them. Of course, the overall sub design has improved along with it's initial quirks. |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 747 Registered: May-05 | so, as far as amps go, the D class has come a pretty long way, i agree. but do you think that the subs followed the amps or the amps followed the sub? because i remember a few amps back in the day (that were huge) could push significant watts. but as you said, they were expensive. but now with the sql subs as they are, class d 1200 watt amps are popping up all over the place. so i guess mypoint is, if the subs had the highexcursion ability back then, do you think amps would have made a way, or was it the amps that were the impetus for the evolution of the sql sub? what was the cause in the recent car audio advancement? cuz it's surely not demand. |
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Gold Member Username: Jonathan_fGA USA Post Number: 4443 Registered: May-04 | I'd say amplifiers before the sub. High power has existed before, but improvements in SMT technology and manufacture of solid state devices has allowed them to become smaller and more cost effective, and D amplifiers have overcome many of their drawbacks due to improved design and available componentry. Demand had a little to do with the SQL revolution, along with increasing competition in the industry. There are more high end companies in audio now than before, and with SQL designs can often come increased SQ as well due to the linear excursion of the subs. Competition bodies like IASCA score for SPL and SQ, and it goes up to 140db. Any decibel below that and you don't get full points. Every company wants to get a step ahead of the competition, and with x-max specs, power ratings, and other methods, it makes the sub look good on paper, whether or not it will back it up will depend on the design. The overall hobby has slumped a bit as well over the last couple of years, while it is still popular, it is losing ground to other consumer goods like Ipods and gaming systems. The more appeal and flair you add, the more potential customers you gain. |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 751 Registered: May-05 | ok. that makes sense then that the amps preceeded the SQL subs. i'm glad it is working out the way it is though. it seems to just be the beginning in advancements in sub production. and amps too for that matter. the rips tech that jl introduced is pretty significant imo. i agree. the biggest distraction in c.a. to me seems to be import tuning. all the mags that used to be on the shelves back in the 90's are gone. i have to go all the way out to towers records to pick up even my mainstream mags. but you can pick up at least 10 cartuner mags at any given 711 or borders book store. i love cars and i think i would love import tuners, but i'm 6'5''. i can't fit inside any of the newer cars and look as cool as the vehicle (hence, the expedition). all the shops i know focus on quantity without quality when dealing with their sq installs. they could care less. they compensate by selling cell phones and installing alarms, navigation, and HUs. and also with iasca, you get deducted one point for every db above the ceiling as well. |
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Gold Member Username: Jonathan_fGA USA Post Number: 4461 Registered: May-04 | I totally agree with the research that has come along in the last few years as well. Manufacturers used to argue mainly on cone material and surround type, but now the motor designs are really coming to see some big advancements. Ten years ago you wouldn't have dreamed of a subwoofer having 10mm of excursion and still being below 1% distortion. Now with motors like XBL^2, it's easy. Dan Wiggins is one of the most intelligent designers in the industry today. Companies like JL Audio also dedicate a great deal of time and effort into their FEA, and it pays off. Of course, Scan-Speak, SEAS, Dynaudio, JM Labs (Focal) and others have come across with some excellent products over the last few years as well. I'm anxious to see what happens with Adire over the next few years, though, Dan has mentioned an XBL^2 tweeter design prototype with 4mm of stroke ONE WAY. Basically, a tweeter that can support a 500hz 1st order crossover, possibly 300hz on a 4th order. That REALLY opens up some possibilities, especially in a car  . |
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Gold Member Username: Jonathan_fGA USA Post Number: 4462 Registered: May-04 | Assume that tweeter crossed at a normal frequency like around 3khz, though, with 4mm of stroke, the only thing I can think of is PAIN. Most tweeters would be happy to have 1/10-1/20 that amount. |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 758 Registered: May-05 | yeah, i recall that being a big deal. many people are waiting to see how successful adire is at actually bringing the theory into fruition. i still don't understand the significance of such an achievement though (even after your brief explanation). what would be the applications of such a driver, and what would be its potential impact on components as we see them today? |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 759 Registered: May-05 | would it just exclude (or incorporate) the need for a midrange. i.e., 3ways would essentially become obsolete? |
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Silver Member Username: Sploosh56Ohio Post Number: 840 Registered: May-04 | I think a good example of subwoofer efficiency would be glasswolfs system that consisted of the pair of old school cerwin vega subs. |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 766 Registered: May-05 | i'm a sq head. no denial. let's move on. so, of course, i was reading the new october CA&E and it seems we have yet a new contender in the sql revolution. the new CV stroker pro has turned over super numbers accross the board (88/100 total). the driver is extremely flexible in its applications. it has >30mm xmax and still maintains extreme linearity by use of its multi magnet air gap (mmag) technology. yes, it has two motors AND two spiders. foul up: 1,700 bones. it seems like they were in the lab for quite some time with this one. long enough to have adire shoot out the gate with xbl2 that yields identical results with 1/4 the cost. i'm guessing CV will fade right back into another of their decade long states of obscurity after Adire, Sound Splinter, and RE go public with their new subs. it seems to me with all of the great sales (and the investment in custom baskets), all companies can now afford to invest in marketing their product in magazines now. seems like they played (and are still playing) chess with their marketing. leek the product into the underground scene to test it and create buz. then unleash the final product on the masses in bulk. i can only imagine how exciting a time like this must be for companies such as adire. as far as CV, they are like Driv3er compared to San Andreas. besides the fact that that they actually created what seems to be a great product, it's still unlikely to yield the profit that was anticipated to justify the time, research, and money invested. just my take. but we'll see. |
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Gold Member Username: InsearchofbassPost Number: 3457 Registered: Jun-04 | yeah wahl for the average user the old school did seem to be the way to go. It wasnt till a few years after I was into car audio that mtx made the scene with 1000 watt subs and even then I was thinking why? Wrong direction but then again its has served other positive results. As for your take mikechec9 I agree with your logic and your theories on leaking to the underground but the one thing ill never understand is how a company expects big profits and demand on a sub in the 700 dollar range like jl to the 1700 you mentioned with cerwin vega. Its almost as if its more braging rights and sensationizing the company name to cause a buz in the industry more than profit driven. |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 767 Registered: May-05 | yop. i can say, in jl's defense, they have ALWAYS been ahead of and on top of the game. their many years of research have ensured their place on top of the mound. it's just that now, there are all of these internet brands that do just as good if not better than JL. the mainstreet commercial consumers still insist that JL is the end all to be all, when that is surely now not the case. so my point is that RE, SS, and Adire will be approaching the sales from a bit more of a commercial stance (no more on line purchasing, only dealers). but there will always be those to whom you're referring who like to brag about the cost of their subs, and both RE and Adire have manufactured subs in that range to compete. while honestly, i maintain that the brahma MKII is a superior sub to the w7 in sq and the w6 in spl and was purchased for 350.00/sub. jl is currently trying to compete along the same lines, but the w0 is like those bottom line benzes that only came about after ford got hold of them. they can't hope to perform in the same league as the larger benzes, but the name is enough for most. eclipse has fallen to the waiste side first because of the price of the Ti and i think JL is on the verge of being another "Porche." only the true fans will be there to continually purchase them. technology has enabled other brands to perform on par, and sales will reflect that. |
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Anonymous | for some companys there time to shine will come and go.. but for other companys they simply make mistakes.. being said from the porche comment ppl tend to cling on a brand based on memory of something good with that name on it.. such as kids growing up to buy honda civics from the honda dirt bikes they used to ride which has turned out great for honda.. and they are performance matched unlike the new hemi engines that came out that are more of a memorbilia marketing strategy that doesnt bring back that of the original.. ive seen enough of that game with coca cola |
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Gold Member Username: Jonathan_fGA USA Post Number: 4471 Registered: May-04 | Adire isn't exactly staying cheap. Seen the prices for their new stuff? "i still don't understand the significance of such an achievement though (even after your brief explanation). what would be the applications of such a driver, and what would be its potential impact on components as we see them today?" Tweeters don't really need the excursion, but they definately need the linearity. Regardless of x-max, XBL^2 has the added benefits of a wide BL curve, low inductance, and very little extra cost achieving that. In midbass drivers, it applies to drivers such as their Extremis 6.8, which has 13mm one way excursion, drops down in the 20s in a room (ported box tuned to 30hz), and maintains low distortion output. Controlled rolloff and response up to 5khz, inductive rolloff is above 8khz. In comparison, drivers such as those from SEAS, Scan-speak, and others don't have half the excursion and most have more inductance. Linearity of most of those isn't as good, either. Basically, XBL^2 has the ability to make a small driver seem much larger, or a large driver stay very linear and have the utmost in control, high output, and excellent SQ. They have subs that can produce excursion at 10mm and still keep distortion below 1%. That's a breakthrough in itself. But keep in mind that you can make the best 6.5" in the world, but that won't make it the best midbass, or the best midrange. It just makes a good compromise when the application demands it. |
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Gold Member Username: Jonathan_fGA USA Post Number: 4472 Registered: May-04 | BTW, if you want to look further into speaker design theory, look at this site: http://www.lenardaudio.com/education/01_eduintro.html Extremely informative for those that want to learn a little more about speaker design and the challenges facing every system. |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 773 Registered: May-05 | very interesting reading. adding it to my favorites and personal portfolio. thanks. |
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Silver Member Username: PhuktupbassheadScottsdale, Arizona United State... Post Number: 207 Registered: May-05 | ...so would it be safe to say (in your, Jonathan's and Mikechek9's, opinions) that the xbl2 technology in motors is definately the best for efficiency, performance, output, spl, and sq that is on the market today? If not, what motors do you favor? Also, which subs currently consist of the xbl2 technology. And, if you favor other motor designs... which subs are equiped with it? Thanks. Very interesting thread, by the way. |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 790 Registered: May-05 | like jonathan said, the xbl2 tecnology has it's benefits, although i'm not familiar with the drawbacks stated. i'm a sealed, high volume sq guy myself, but i've seen a single 12" brahma in a ported enclosure hit 142.5db. whether or not i could distinguish an electric bass from an upright bass in such a box probably wouldn't matter much at that point :-) but it is certainly an extremely efficient design. particularly when you take into account the measures that CV has painstakingly gone through to achieve similar results (it's really rediculous, but seamingly effective). with regards to performance and linearity as it is, the LMT motor from TC sounds used on the new Sound Splinters looks very promising. both designs offer extreme linearity at extreme excursion, but at low production costs. hence, their efficency. i'm not nearly as proficient with other motor typologies as Jonathan (i'm hoping he'll choose to elaborate), but here are thorough explanations of both of these: xbl2 http://www.adireaudio.com/Files/XBL2DetailsPaper.pdf http://www.adireaudio.com/Files/XBL2TechPaper.pdf LMT http://www.soundsolutionsaudio.com/forum/index.php?showtopic=2748 |
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Gold Member Username: Jonathan_fGA USA Post Number: 4480 Registered: May-04 | I'll go into it in a couple hours, I have to go out of town for a bit. |
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Gold Member Username: Jonathan_fGA USA Post Number: 4481 Registered: May-04 | As far as topologies, these most common ones are overhung and underhung. Overhung uses a longer voice coil and a shorter gap. It is called overhung because the voice coil is longer than the top plate is thick. This design is typically the most efficient user of flux since you're using a focused strength within a narrow gap, and they make use of a good portion of strength outside the gap as well (note: extreme overhung designs do NOT apply). This amounts to more BL initially (close to center). As you move further from the gap the BL drops off, which is referred to as a parabolic BL curve. Benefits include good BL use, cheap to build, and the long voice coils make for good power handling. Cons are the mass of the long coil, the BL curve, and the deep voice coil clearance required. Underhung is next. This design uses a shorter voice coil and a thicker top plate. This is the least efficient as far as BL use, since the voice coil integrates all of the flux present over it's length, and that length is shorter than the gap it is within. The gap is low flux density since the entire gap must have flux within since the voice coil is smaller than it, opposed to a design with a shorter gap like overhung or XBL^2, which concentrates flux into smaller areas. Pros are an extremely flat BL curve, low moving mass from the short coil, and they can be shallow since there aren't a lot of clearance issues. Cons are lower BL, lower power handling, higher cost due to the thick top plate. Now, XBL^2 is a different animal. It breaks the flux into more than one region so that you have multiple regions of concentrated flux as opposed to a bigger gap. Then, a properly sized voice coil is used, the size will be determined by the height necessary to connect the two (or more) flux gaps. Basically, you'd have it where the voice coil extends from the center of the higher gap to the center of the lower gap, so that as it exits one, it enters another for a smooth transition and no BL loss between the two. This topology combines the benefits of underhung motors, which is flat BL from the control, smaller coil lengths for less inductance and moving mass, and fewer clearance issues. They also have the benefits of a long coil design in the sense of having good flux use (a little less than an overhung, some are equal to), cheaper build cost. The LMT motor from TC sounds has a lot of drawbacks. It uses a very long voice coil, which has high inductance and moving mass to start with. The way that they accomplish the flat BL is through modifying the coil, by progressively adding more coil windings at the ends of the coil to gain BL at higher excursions and compensate for the coil being further from the gap, essentially giving a flat BL curve. This, again, adds mass and inductance due to the coil windings. This runs into another problem. The LMT prototype, for example, used 2 layers of coil in the center, then 4, and 6 at the ends. This means that the gap has to be wide enough to clear 6 layers of voice coil, and results in an overall lack of BL due to the wide gap (it'll be really far away from the 2 layer portion of the coil, and by the time you reach 6, BL has dropped anyway). Now, to lower the inductance of the driver back to acceptable range, you would have to add copper shorting rings, which will again widen the gap and lower BL. If you want to up BL, you'll have to add a lot more motor, again increasing cost. As far as SQ, really all can give good results, just dependant upon the application. Overall in a purist SQ standpoint, XBL^2 and Underhung would be the most popular given the choice. Both offer what you want in a SQ driver, which is low inductance, a flat BL curve, low distortion, and low moving mass. For SPL, long coil/short gap is more popular since you have a more focused BL in the center of the gap. You'll get more motor strength at that point, increasing efficiency and SPL, which especially helps when running woofers in a ported box. Efficiency depends on which point you're talking about. Whichever design has more BL will be more efficient (all other things being equal). If you have more BL at the center, then you will be more efficient with lower power. If you have more BL at 20mm, then it will be the more efficient design at that point. All perform differently at various excursions. |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 804 Registered: May-05 | and that's one to grow on. ok jonathan. technically speaking, what is it that you like of the id max over the brahma? does it have more to do with the correlation beween the motor and suspension, or is it just an issue of subjective listening preference? |
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Gold Member Username: Jonathan_fGA USA Post Number: 4483 Registered: May-04 | Couple of reasons. The ID Max v3 had more BL than the Brahma (Brahma was Mark I at the time, Mark IIs have upped the BL). While it does have a more parabolic curve compared to the flat BL curve of XBL^2, the ID Max had more BL than the Brahma at points where there was less excursion (roughly from between 10-20mm of excursion, dependant on forward or rearward motion). The ID Max has a looser suspension, a lower resonant frequency, a lighter cone, and more surface area. Basically, what I'm getting at is that it is a better ported box performer, and can take advantage of larger boxes more exotic applications like Aperiodic membranes better than the Brahma can. Remember that excursion may as well be thrown out the window in a well designed ported box. It is plain out wicked in a ported enclosure tuned to 25hz or so, and sounds fantastic doing so, giving a smoother frequency response than the Brahma and similar subwoofers. I try to keep my options open as far as enclosures, in the case that I change vehicles in the future or whatever (even though by the time I do I've usually got a new wishlist ). The Id Max is also more efficient, and that to me is always a plus (as long as there aren't big sacrifices in getting that efficiency). Another reason is that at the time, Adire was still getting their stuff straight with the glue issue (that's why you see all the reconed Brahma forum topics, the glue was the problem). Adire was very straightforward with this and I mean absolutely nothing bad towards them by my statement above, all I'm saying is that when I bought the sub it was during the iffy time to get a Brahma. Head to head in SQ, these are very equal performers, just in different areas. The Brahma is better in the lower bass region, but has a rolloff in upper bass (around 60hz and up). I felt the ID Max was better with midbass transition, and from my evaluation of the two, the ID Max (to my ears) was tighter and more defined at higher frequencies, while the Brahma was a tad on the muddy side. Overall, the ID Max leans more to the tight, punchy side, while the Brahma is a little deeper and has an airy feel to it. As far as the upper bass rolloff, this isn't a huge issue in my application since I have an 8" midbass that can drop to 60hz quite easily, but like I said above, I like keeping my options open, which will pay off in the end as I'll be working on a small truck soon and I highly doubt 3 ways are going to make it. If I want very loud low bass out of my sub, I can whip up a 2.5 cu ft net ported box, tune it to 25 hz, and have extremely clean, authoritative output down low. No regrets here, and I wouldn't have any with a Brahma either. |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 816 Registered: May-05 | i've never been as clear as to the differences between two drivers :-) thanks. good points, then.especially the one regarding the glue on the brahma (first hand experience). i hope they won't give me too much grief when it comes time for replacement. is it something inherently wrong in the design or can it be rectified? also, i understand that any sub with a qts less than .45 is a prime candidate for an aperiodic enclosure. i'm currently working towards contruction for one. is their something besides the brahmas' .43 qts rating which i should consider more closely b4 proceeding? |
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Gold Member Username: Jonathan_fGA USA Post Number: 4487 Registered: May-04 | "also, i understand that any sub with a qts less than .45 is a prime candidate for an aperiodic enclosure. i'm currently working towards contruction for one. is their something besides the brahmas' .43 qts rating which i should consider more closely b4 proceeding?" Around .35 or less is REALLY good. Basically, as you go lower in Qts, the subwoofer is damped better (overdamped). Higher Qts subs tend to have resonant peaks that plain out sound like crap in an Aperiodic alignment. That being said, the RE X.X.X., ID Max, basically subwoofers that are designed for ported boxes, work better aperiodic. Image Dynamics offers kits to do AP, no tuning required on your part. |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 817 Registered: May-05 | First, i'm trying to locate an image and such of the ID ap kit. can't find any pictures or methods of purchase. ok. so here comes the real question (from my obsessive compulsive nature). will my brahmas sound exceptional in an ap? and with my brahmas, is there any way to equal the sq (transient response and damping) of an aperiodic installed id max. and also maintain spl of 140 (5 more than iasca standard) and relative deep output? i really value the low end of these subs. i want it all and don't mind switching up if I HAVE to (since i really need 4ohm subs to match my amps anyway). but i would rather maintain my current subs if possible. i can't imagine anything sounding much better. |
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Gold Member Username: Jonathan_fGA USA Post Number: 4489 Registered: May-04 | "will my brahmas sound exceptional in an ap?" They'll sound pretty close, but won't work in one like an ID Max or X.X.X. would. "and with my brahmas, is there any way to equal the sq (transient response and damping) of an aperiodic installed id max." AP in general is superior to sealed for both transient response and damping. While the Brahma would retain it's advantages over the ID Max for SQ (linearity and transient response due to inductance), for overall frequency response and SQ when referring to an AP membrane, I'd give the Max an edge. "and also maintain spl of 140 (5 more than iasca standard) and relative deep output?" AP is inefficient, less efficient than sealed. I'd say around 3db down. Deep, yes, it can get deeper than sealed does down to the resonant frequency, but below that you run into some issues. Now, I'm referring to a regular Brahma, you said yours had a Sadhara motor, though, right? |
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Silver Member Username: Mikechec9Chicago/atlanta Post Number: 818 Registered: May-05 | exactly. how might that alter the equation? |
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