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New member Username: InsearchofbassPost Number: 8 Registered: Jun-04 | Now i know i will take heat for this but hear me out. I have seen post after post trashing volfenhag subwoofers accross the internet. I have heard the 47 line and the 48 line all of which sounded very good in sealed and ported enclosures. Just the other day i had a friend who had a 2001 chevy s 10 extended cab with 2 4812's and it hit at the 130's at 59 hz which i think was his resonant frequency for that truck with a cheap 300 rms boss amp who knows the peak power. now i ran the specs of this sub and he had his in 1.70 cf each chamber but if he gave them 4 cf a piece he would boost his low end 12 db now you take the results we had in the 1.70 cf box and add the 12 db in the new box were talking 140 db easy off of that cheap boss amp 300 rms and they can handle much more power than that. To all who ask about them try them you wont be disappointed. ps...i think the 48 series have twice the xmax of the 47 line also and a little more rms power handling worth checking into. thanks for listening and happy booming, in search of bass |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 4077 Registered: Dec-03 | your math is incorrect. that "12dB boost" isn't 12dB in SPL. It's 12dB up in the signal.. that's a relative value based on the original signal.. it doesn't mean it's 12dB louder. 130 is ok I guess, but any system should hit that range. The car I used to drive was hitting 151dB with two twelves in a ported box, with an amp rated at 80 watts x 2 @ 4 ohms. I've seenb etter but that was with a perfect C weighted curve, too. the problem with volfenfag is that their subs are very poorly made and they have a high failure rate, along with very poor performance and SQ at high excursion. That aside, I'm glad you're happy with yours or your friend's though. After all, who cares what anyone else thinks. You're the one who has to listen to it day to day. My current project I'm toying with is using two Orion H2 12.2 subs with an Orion XTR2250 on each one. I'm toying around with AP box designs.. It's not designed for SPL but I should still hit at least close to 150dB, since each sub will have 1Kwatt going to it, and 29mm of Xmax one-way per sub. here's hoping it pans out as planned. |
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New member Username: Sancho886El Cajon, CA US Post Number: 4 Registered: Jun-04 | there is a reason why people trash volfenhag. they are just not good quality. i had two of the 48 series myself. those things blew real quick. thats fine if you and your friend like them but you shouldn't recommend them to people only because you heard some one time that are ok. |
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Bronze Member Username: LoudnobnoxiousPost Number: 42 Registered: Jul-04 | just to let you know, x-max doesnt determine much when dealing with spl. certain models of DD woofers move very little but they will kill subs that have twice the xmax. |
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Bronze Member Username: RedskinLondonEngland Post Number: 66 Registered: Dec-03 | "AP box designs"? Is that aperiodic designs? |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 4081 Registered: Dec-03 | yes aperiodic. xmax and cone surface area roughly determine SPL because those two specs determine how much air the driver can displace at peak output. there are other factors but those are the big two. just like an engine piston's bore and stroke. |
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New member Username: InsearchofbassPost Number: 9 Registered: Jun-04 | glasswolf help me to understand what you mean by it increased the signal not the spl i used linear teams program to see this curve. I am willing to learn thats my whole reason for this testing i am doing with my cheap meter and running spec on the program and running single hz tones in the car or truck for this example. ps.........roger q...........i heard like 4 cars now 3 times older 47 series one time 48 series and honestly they really did sound good and yes i do know sound quality. |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 4091 Registered: Dec-03 | Sean, go to www.bcae1.com and on that right menu, look for crossover slope basics. look at the graphs there, and see how slopes work. then seeing how the X axis is frequency (octaves), and Y axis is amplitude in dB, you should be able to see how a bass boost button would add +12dB let's say. Being relative, it's 12dB above the baseline which is essentially zero. |
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Bronze Member Username: SouthernrebelLouisiana USA Post Number: 88 Registered: Mar-04 | Sean, think of it like this...the bass boost is the "volume" for your amp... so if you set your volume on your HU to 3/4 and set the gains on the amp w/ the bass boost all the way down you will have little or no clipping, now by turning you bass boost up it would be the same as turning your HU up, but it would only affect the signal to the amp not your other speakers.....so if you turn your HU to 3/4 volume and turn the bass boost on the amp up YOUR AMP WILL CLIP!!! in other words you can use your bass boost to some what control the volume of your subs, at least up to the point at which the amp starts the clip. |
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New member Username: InsearchofbassPost Number: 10 Registered: Jun-04 | ok i think im starting to understand a difference so are we actually only talking a 3 db increase then since the sesitivity is a 12 increase in keeping with the crossover example glasswolf? thanks, in search of bass |
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Bronze Member Username: InsearchofbassPost Number: 15 Registered: Jun-04 | Ive talked with my friend whom i trust his imput as well and we both think what ive found is correct. Glasswolf i think you missunderstood what i was telling you initialy if the curve is at one point and it changes by 12 in increase then its an increase by 12 nothing can change that. So i belive this chart to indicate 12 db extra based on my previous in truck test results. Now i know its hard to believe a pair of volfenhags would hit over 140 db but they can and be able to be used every day with 300 rms. not too shabby for so called flea market subwoofers. thanks, in search of bass |
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Silver Member Username: Jonathan_fGA USA Post Number: 825 Registered: May-04 | No, you're still wrong. Sealed enclosures roll off at 12db/oct. Larger boxes will control the cone less, basically the sub will perform more as if it were in an infinite baffle mounting. If you were to see the sub's anechoic response in that box, you'd see that the enclosure would roll off at a certain frequency at a rate of 12db/oct, so an octave lower, the sub will be 12db quieter. A larger box doesn't make the sub louder, it just gains back what you lost in the rolloff. When you make a box larger, you get extended bandwidth, but usually lose SPL as the sub has nothing controlling the cone, aka no compression. In a car, you may see a slight increase at lower frequencies due to cabin gain, but you will actually lose SPL at higher frequencies such as the 59 hz you metered at, and no you won't gain 12db by adding a larger box (a lot of people wish it was that easy). 2 good 12's should hit in the 140+ region, 130s isn't that great for 12's. Go ahead and try the larger box, you'll prove my point, it isn't going to make you hit 140s. |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 4176 Registered: Dec-03 | I thought you were trying to say the bass boost button on the amp would give you +12dB. I must've confused this with another thread. Anyway, increasing box volume isn't going to do that either, just for the record. The only way you'd gain +12dB changing boxes is if you went from ideal sealed to a very well designed 6th order bandpass box.. then it'd be a matter of luck as much as design. distortion would also be masked this way and power handling would just about triple if done right. since you're measuring at around 60Hz, you're really not going to help anything going to a larger sealed box. what you need to do if this is strictly for SPL, is go bandpass 4th or 6th order, or go ported. tune the ports to the frequency you're after for SPL, which would be the cabin's sympathetic frequency. if you have doubts, build the box, then get it metered to see the actual results. the math is always theoretical and there are always other factors to consider. |
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Bronze Member Username: InsearchofbassPost Number: 16 Registered: Jun-04 | ok i see now i realize you guys definately know more than i do but i was confused in part because of an installer i know who has and out of car test box sealed or ported and he said all he did we keep im proving the air space until the spl stopped going up on the spl meter so i assumed larger was better. Appologies. on another note i have some lanzar dc 12s from the original lanzar line i hope. I am going to put them in a 4 cf sealed box for two of them. how well do you think this will be using rms power up to their max and can go beyond. I am using a mtx 81000d amp capable of 1500 watts rms at 14.4 volts and 1000 rms at 12.5 volts i think using both these subwoofers. thanks, in search of bass |
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Bronze Member Username: InsearchofbassPost Number: 19 Registered: Jun-04 | hey guys i just wanted to post the results of my newest box. I put my cousins kicker comp 12 (cheapest line) in a box i had sitting around and we cut it down to fit in his trunk. The old box it was in was about 1.70 cubic feet sealed and hit about 126 db on a profile 300 watt rms amp at 3 quarter gain. Now the new box is about 3.64 cubic feet ported at about 38 or 39 hz orginally at the 36hz till cut down in box size. And as the program showed that i used it is definately cleaner and louder at the low end. I havent measured it with my meter yet but i am pleased with the results. The only thing i would change is the tune frequency or just seal it. I will post my results after metered. thanks, in search of bass |
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Bronze Member Username: InsearchofbassPost Number: 37 Registered: Jun-04 | ok i wanted to post this so i can let you guys no i understand now why i was wrong and so that i dont mislead anyone by my incorrect box results for the volfenhags. The reason i got the box size wrong is that i used linear teams online box program and the qtc according johathan is coming out wrong. So i got another program and ran another woofer that him and i have been talking back and forth on and now my qtc matches his. So now i ran the volfenhags again and they will work in only a slightly larger box then recomended by factory for daily use. ps....for the record a 54 hz tune looked promising in the 3.40 cf box minus decrease of air for woofer basket etc for the s 10 extended cab we had them in to peak at his 59 hz resonant frequency. thanks, in search of bass |