Chase Wallace Posted January 10, 2017 Report Share Posted January 10, 2017 Which combo would move more air and get louder? If it makes any difference lets say that both combo's are in optimal ported boxes with 4000 rms total. Two 15" subs with 30mm X-Max and 353 square inches of surface area or Four 12" subs with 19mm X-Max and 453 square inches of surface area 11mm more X-max with 100 square inches less or 11mm less X-Max with 100 square inches more? Can anyone tell me how close these two combinations are and how much more X-max it would take for the losing combination to be equal? Link to comment Share on other sites More sharing options...
hdorre Posted January 10, 2017 Report Share Posted January 10, 2017 The two fifteens have 78 more cubic inches (23% more) of volumetric displacement. On 5/8/2011 at 7:38 PM, Kranny said: On 5/8/2011 at 7:35 PM, 'Maxim' said: It hurts me inside when I read stuff like this and remember you're 15 LMFAO so true Mitsubishi 3000GT (Old Build) Headunit: Pioneer 80PRS Frontstage: (2) McLaren Audio MLT-2 Tweeters & (4) PRV Audio MR Series Neo 6.5" Mids Substage: 4 15" Hybrid Subs - Tantric Motors & Sundown Softies Amps: Banda 2.4D Amp (Tweets), American Bass VFL 350.4 (Mids), and (2) Ampere 3800s Electrical :Singer 260A Alt & JY Power Lithium 2005 Chevy Colorado Ext Cab Headunit: Pioneer 80PRS Frontstage: 4 PRV 700Ti Tweets & 6 10" Delta Mids on 3000wrms Substage: 6 Fi BTL 18s in a 4th Order Walkthrough on 3 Wolfram 4500s Electrical: Singer "390" and JY Power My Official Feedback Thread Link to comment Share on other sites More sharing options...
Chase Wallace Posted January 10, 2017 Author Report Share Posted January 10, 2017 10 minutes ago, hdorre said: The two fifteens have 78 more cubic inches (23% more) of volumetric displacement. Thanks! It seems my suspicions were correct them. If you don't mind could you show me the formula to calculate this so that I can apply it in different comparisons? My planned build is kind of strange in that I think it would be easier to fit four 12's than two 15's but I will probably try to stuff the 15's in there anyway if I can't find four 12's that would get as loud or louder for around the same price range and given the same power. Link to comment Share on other sites More sharing options...
hdorre Posted January 10, 2017 Report Share Posted January 10, 2017 No problem. Vd= SD ≈ xmax vd = volumetric disp sd ≈ cone area xmax is stated. The only thing I did was convert it to inches, from centimeters. On 5/8/2011 at 7:38 PM, Kranny said: On 5/8/2011 at 7:35 PM, 'Maxim' said: It hurts me inside when I read stuff like this and remember you're 15 LMFAO so true Mitsubishi 3000GT (Old Build) Headunit: Pioneer 80PRS Frontstage: (2) McLaren Audio MLT-2 Tweeters & (4) PRV Audio MR Series Neo 6.5" Mids Substage: 4 15" Hybrid Subs - Tantric Motors & Sundown Softies Amps: Banda 2.4D Amp (Tweets), American Bass VFL 350.4 (Mids), and (2) Ampere 3800s Electrical :Singer 260A Alt & JY Power Lithium 2005 Chevy Colorado Ext Cab Headunit: Pioneer 80PRS Frontstage: 4 PRV 700Ti Tweets & 6 10" Delta Mids on 3000wrms Substage: 6 Fi BTL 18s in a 4th Order Walkthrough on 3 Wolfram 4500s Electrical: Singer "390" and JY Power My Official Feedback Thread Link to comment Share on other sites More sharing options...
Chase Wallace Posted January 10, 2017 Author Report Share Posted January 10, 2017 6 hours ago, hdorre said: No problem. Vd= SD ≈ xmax vd = volumetric disp sd ≈ cone area xmax is stated. The only thing I did was convert it to inches, from centimeters. So working it out... Two 15's with 30mm Xmax Vd= 353 x 1.1811 Vd= 416.9283 Four 12's with 19mm Xmax Vd= 453 x 0.748031 Vd= 338.858043 416.9283 - 338.858043 = 78.070257 Vd= 78 cubic inches more for the two 15's after Xmax is factored I think I got it! Thanks! Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted January 10, 2017 Report Share Posted January 10, 2017 Keep in mind that greater Xmax is only beneficial if you are going to be pushing that sub to a greater level of excursion. If both subs are only going to be pushed to 17mm of excursion at the box size/tuning/input power you will be using greater Xmax potential of one sub is irrelevant. With ported box systems the peak output is usually around tuning where cone excursion is at a minimum so greater Xmax isn't always an important factor. Sealed box systems are a different situation. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
Skullz Posted January 10, 2017 Report Share Posted January 10, 2017 Want more air movement? Controlling cabin gain will get you farther along than xmax. 01 Ford focus ZX3 Pioneer AVH-X491BHS PPI PC 4800.2 Morel Maximo 6.5" x2 Link to comment Share on other sites More sharing options...
Chase Wallace Posted January 10, 2017 Author Report Share Posted January 10, 2017 2 minutes ago, Triticum Agricolam said: Keep in mind that greater Xmax is only beneficial if you are going to be pushing that sub to a greater level of excursion. If both subs are only going to be pushed to 17mm of excursion at the box size/tuning/input power you will be using greater Xmax potential of one sub is irrelevant. With ported box systems the peak output is usually around tuning where cone excursion is at a minimum so greater Xmax isn't always an important factor. Sealed box systems are a different situation. So if I can't compare by cone area or even total volumetric displacement then how could I figure out which combination has the potential to get the loudest? Why wouldn't I be pushing the sub to the highest level of excursion at maximum volume. I mean to me it sounds like you're saying that Xmax doesn't really make a difference when you don't have the volume all the way up. I'm not saying this is what you're actually implying but I'm saying I don't really understand. This was all considering the subs would be in the correct box size, tuned to the recommended frequency, and given slightly more than rated power or actually a lot more. Given that all that then what better way is there to calculate which setup should be louder than using the sub's total volumetric displacement? I mean in the end aren't we basically trying to move air? If the subs were unable to reach their full Xmax then wouldn't that mean they were in the wrong box, tuned to the wrong frequency, or under powered? I just don't understand why a sub with 30mm Xmax rated at 1500 RMS and given 2300 RMS wouldn't be able to reach it's full Xmax and move its full volumetric displacement potential. If I'm just totally not getting it then seriously please teach me more before I waste a huge amount of money "to me". Link to comment Share on other sites More sharing options...
Chase Wallace Posted January 10, 2017 Author Report Share Posted January 10, 2017 32 minutes ago, Skullz said: Want more air movement? Controlling cabin gain will get you farther along than xmax. I'm wanting to figure out which subs or combination of subs have the potential to get the loudest. Surely there is some decent way to compare one sub to another without just looking at brand names or testing every one in every vehicle... Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted January 10, 2017 Report Share Posted January 10, 2017 21 minutes ago, Chase Wallace said: So if I can't compare by cone area or even total volumetric displacement then how could I figure out which combination has the potential to get the loudest? Why wouldn't I be pushing the sub to the highest level of excursion at maximum volume. I mean to me it sounds like you're saying that Xmax doesn't really make a difference when you don't have the volume all the way up. I'm not saying this is what you're actually implying but I'm saying I don't really understand. This was all considering the subs would be in the correct box size, tuned to the recommended frequency, and given slightly more than rated power or actually a lot more. Given that all that then what better way is there to calculate which setup should be louder than using the sub's total volumetric displacement? I mean in the end aren't we basically trying to move air? If the subs were unable to reach their full Xmax then wouldn't that mean they were in the wrong box, tuned to the wrong frequency, or under powered? I just don't understand why a sub with 30mm Xmax rated at 1500 RMS and given 2300 RMS wouldn't be able to reach it's full Xmax and move its full volumetric displacement potential. If I'm just totally not getting it then seriously please teach me more before I waste a huge amount of money "to me". Volumetric displacement is directly related to output for sealed boxes but for ported boxes it isn't. The reason for this is around the tuning frequency of the box ALL the output is coming out the port and nearly NONE is coming from the cone. At this point there is very little cone movement, so Xmax is irrelevant. Many subs these days have so much excursion capacity that they will almost never be pushed to their mechanical limit. Mechanical isn't the only limit subs have though. They are also limited by thermal capacity. In a ported box at some frequencies (like around tuning) you will be limited by thermal capacity before mechanical. Other frequencies you will be limited by mechanical capacity, but with ported boxes that's probably not where peak output will be. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
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