Flat Cones, Reversed surrounds... and all the others
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Silver Member Username: IronslaveOffutt AFB, Nebraska U.S.A. Post Number: 318 Registered: Sep-05 | ok i was wondering theres some interesting designs ive seen over the years... i was wondering about opinions on em. reverse surrounds... sounds like poor accuracy with that idea... Flat cones... i would think that this would also give poor SQ? do magnets make that big of difference when it comes to how heavy they are... |
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Gold Member Username: 54danny54Betsy layne, Kentucky..GO... USA duh Post Number: 1986 Registered: Nov-04 | ok...by reverse sounds, do u mean like underhung surrounds?, that i think is supposed to increase accuracy of a woofer and the flat cone thing...subs really arent flat coned(or most isnt) its the dustcap being so big |
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Gold Member Username: Mikechec9Post Number: 2251 Registered: May-05 | Flat piston- I have yet to see one maintain production. They always fail and become discontinued. Reversed surround- Really only seen MB Quart do this (and with good results). Magnet size means horse whiskers. If anything, it's the width of the magnet that makes the most difference. But yes, the bigger the magnet, the heavier the sub  |
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Silver Member Username: Safe_crackerChicago, IL US Post Number: 431 Registered: Jan-06 | I agree with Mike on the "true" flat piston type, think Audio Pipe had a couple and a few others. The closest you will find is like the slight parabolic shapes used on like some of RE subs and JL W7's, a much more rigid design. A flat piston suffers from distorting of the cone due to a flexing during compression, ultimately problems occurr under high power demands. I think the reversed surrounds are supposed to help increase excursion while retaining most of its linearity. I could be wrong, but not usually, lol...Polo. |
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Silver Member Username: MixneffectOrangevale, Ca. USA Post Number: 858 Registered: Apr-05 | Reversed surround has been arround since the early 70's. You don't see em arround because they were high end for one, and they are almost absolete because of age, but nevertheless its not a new invention. Reversed surrounds help in packaging, believe it or not. That way the suspension is not weakened prior to operation, and you can stack them face to face, and/or upside down without golf tees. I am not sure that it helps SQ in any way. It may even be a showpiece at best. Flat diaphragms are also a designer showpiece. It is mainly used in subwoofer application where the desperation pattern is not a big concern. There are a lot of new flat diaphragm speakers out today even in arrays, but IMHO they suck. Regular magnets usually get more powerfull due to size, but you also got to look at the pole pieces. The pole pieces (usually iron) usually sandwich the magnet and they are also heavy. The new generation magnets (neodymium) are very strong and usually smaller in size. They are starting to become the trademark for speaker magnets. |
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Silver Member Username: PelonaAlabama Post Number: 917 Registered: Dec-05 | dis wut u mean by reverse surround?http://www.woofersetc.com/index.cfm?fuseaction=product.display&Product_ID=3416 and i think earthquake makes a flat cone sub |
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Silver Member Username: AlteraudiousaConcord Post Number: 434 Registered: Jan-06 | there have been quite a few true flat cone designs. Basically you have a piston going strsight to the underside of the cone. No Diaphragm on them only piston to usually a small plate on the underside of the flat surface cone. PPI had one a while back, ED had them on the K, O and A series and Phase Audio had one, the Aliante and a few others have popped up but most are discontinued due to production problems or design problems, most are not continued due to consumer wants. Arc has one but I haven't seen it or looked at its design to see if its a true one or not. Most flatcone subs have a smaller power requirement and strict mechanical limits. I don't think they really suffer from distortion of the cone as they're made of kevlar or some matter of the sort and the piston is usually a little bigger than normal. They suffer from the extreme pressure at the joint o the piston and the cone at high excursion from my experience with them. The ED A series showed this on the 12 and 15 as it could not properly hold RMS over 900 very well and especially would run into problems with 1000rms or more. Those I have heard, I really want to hear the ALiante(its a shallow depth one) have had very good SQ and are very tight and accurate. Output is not as much as with the regular cone but the SQ on the subs were excellent. but alot of how a sub is made and made with IMO is becoming more consumer "image" driven. The Neo magnets (unless there's something that I don't know about) should work but I think alot of customers think or see small magnet and think its a weak sub. Everyone wants to see something big. Alot of people think the bigger the magnet the better the sub. IE-MTX Jackhammer, big magnet big sub, completely useless but people always talk about them. I even like the look of a hefty magnet just for cosmetic reasons. |
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Silver Member Username: YukhuiMyrtle Beach, South Carolina USA Post Number: 264 Registered: Jan-06 | MTX has a sub (I think the RL or something series) but anyways it's there "competition" woofer and it has an reversed surround. I have some old stock Mercedes speakers with a reversed surround (they suck). |
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Gold Member Username: Jonathan_fGA USA Post Number: 5770 Registered: May-04 | Reversed surround is mainly to save space (grilles aren't so obtrusive, etc.) Hybrid Audio is doing it for their new speakers. Doesn't really help or hurt anything, it can be just as good as the opposite. The packaging side of it that mixneffect mentioned is a viable argument. Flat cones-main problem is the joint with the former. The only way you could really get a truly solid mount with the voice coil former is if you were to literally connect it through the cone and support it from both sides, then bond it with the former with extremely strong adhesives. The other problem in most flat cones were inherent resonances due to a weaker (floppier) cone. Obviously a flat cone isn't going to be as strong as a curvilinear design. Theoretically the perfect subwoofer would be as a perfect piston-which would be flat, but there are too many tradeoffs with the design to justify it IMO. If you want an example, the first version of the SEAS L18 (out of their Basic line, the H1142) had a straight cone profile. The second version (H1224) was revised with a curvilinear profile via Peter Larsen's FineCone FEM modelling software. The result was a stronger cone that pushed breakup higher in frequency, indicative of the increased stiffness. |
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Silver Member Username: IronslaveOffutt AFB, Nebraska U.S.A. Post Number: 319 Registered: Sep-05 | awsome input alot of difference in opinion in the posts... yea the reason i was asking is because i was thinking if investing into the MB quarts since they claim a FR of 15Htz the subs i have are she worst ive ever heard and bought them for clipping testing... looks like my Sub out on my HU is bad cause its run fine since i hooked em up to my Line out's and i was just curious on the magnets and the flat pistons... i heard someone mention at one time that magnet size isnt that big of a deal... also that the larger the sub the smaller the magnet... WTF? as for the flat piston i was just curious thanks all Your The Sheit!!!!!! |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 11379 Registered: Dec-03 | a few thoughts.. reversed surrounds.. mainly for looks.. or packaging as mentioned. the speaker moves in both directions equally so the surround direction won't affect cone movement that much. flat piston or flat coned subs.. shallower mounting depth. handy for tight sub locations like single cab trucks. magnets. heavier isn't better. stacked doesn't add as much as a larger diameter magnet. stronger magnet beats heavier, but not too strong. it all comes down to unerstanding magnetics and driver motor design. What's important in the end is the Bl of the sub, which translates to the motor strength. over or under damped subs have their uses, but looking at an XBL^2 or JBL's DDD motor you'll see what a realaly good Bl loks like for a SQ sub. flat and smooth. |
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Silver Member Username: MixneffectOrangevale, Ca. USA Post Number: 862 Registered: Apr-05 | Hmmmm... Come to think of it I remember having a set of 8" Eatons that had the reverse surround. They were classified as long-throw. If you look at a reverse surround it allows the diaphragm to have more linnear travel. A regular surround allows the driver to max only half of the surrounds height or depth (depending which angle you are looking at it from). A reverse surround allows the driver to travel from a (- say 6mm) to a (+ 6mm). This give you a total of 12 mm of travel. The regular surround would only allow you to get a 3 mm travel, since half of the surround is already used up. "I think the reversed surrounds are supposed to help increase excursion while retaining most of its linearity." Good call Polo |
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Silver Member Username: Safe_crackerChicago, IL US Post Number: 453 Registered: Jan-06 | Thanks Mix, I think I remember an add that said that back in the 80's, if I could just remember which one, lol. Polo. PS- 80's were goooood!  |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 11385 Registered: Dec-03 | umm, again, subs move in both directions pretty much equally, so the direction of the surround isn't going to help or hinder excursion.. you'll reach Xmech before you have issues with Xsus. |
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Silver Member Username: Nnnnick_bWeddington, Nc Usa Post Number: 473 Registered: Jan-05 | Just flip your sub over and look at the surround threw the basket of the woofer. Look familiar. Looks like the surround on ne other driver. |
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Gold Member Username: Mikechec9Post Number: 2256 Registered: May-05 | And similarly, if you invert your subs, you essentially have a reversed surround. |
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Gold Member Username: Mikechec9Post Number: 2257 Registered: May-05 | If you invert any traditional sub, that is. |
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