Souldrop Posted October 18, 2014 Report Share Posted October 18, 2014 It really doesn't matter SPL vs bels. You're ultimately arguing semantics especially when you take into consideration the subject matter found on this forum. OP flexing windshield or vibrating coke cans don't necessarily mean a higher spl. It could come down to the design of your car being more or less susceptible to vibrations propagating through the vehicle. Now don't get me wrong higher spl levels flex and vibrate a vehicle more, but you can't really use difference in objects flexing to guess which one is "louder." Get both of them metered or its a moot point. I will say it does seem easier to get SUVs loud compared to closed off trunks with the same equipment (w/o a wall). With fold down seats and hatchbacks you start getting into a gray area where it could be comparable or louder than a SUV. So to summarize: depends on the cars and SUVs in question and ultimately the install. 1997 Lexus ES300 HU - Pioneer MVH 7350 Processor - Helix DSP Front Stage - JBL P660C Mid/high amp - Alpine PDX-F4 Subs - 1 IA Death Penalty 12 Sub Amp - Cactus Sounds PF300.1 Link to comment Share on other sites More sharing options...
AstoSoup Posted October 19, 2014 Author Report Share Posted October 19, 2014 Thanks for all the replies, all very helpful! So different vehicles are built with thicker or thinner metal and some are more susceptible to SPL? Makes sense.... I have always thought SPL was measured in Db's but now see there is a little controversy on this. So to sum up RainStrykes post, "Also remember that the sound pressure (the thing that causes flexing) is not the same as decibels.", Is this true or false? That would explain why the car flexed more, while not producing as much sound to the ear-o-meter. All making a lot more sense to me now though, relatively new to the SPL side of car audio, have always had SQ setups (500-600RMS) and flexing wasn't so much of an issue, lol Head Unit - Clarion VX709 7" DVD Touchscreen Mid/Highs - Front Doors - RF Prime 6.5" component mids. A. Pillars - RF Punch component tweets. B. Pillars - RF Prime component tweets. Rear Doors - RF Punch 5.25" mids. RF Punch 3-way passive X-overs. Mid/Highs Amp - MB Quart Onyx 360.4, 4 channel, 640W RMS. Subs - (2) PowerBass 3XL 15, 1000w RMS, 3" flat wound coil, 562oz motor, 10" spider. Sub Amp - Audiopipe GD6001 @.5ohm, clamped 2825RMS. Box - 9.6 cu^3 net @35Hz, three 6" aero's. Charging - Energizer 120Ah AGM under the hood, MaxLife 75Ah in the rear. Big 3, 140A aftermarket alt. (off brand) Wires - Two JL Audio 2/0ga OFC. runs to rear, 4ga. power/2ga. ground to component amp (OFC), 1/0ga. OFC Knu Konceptz Kolossus Kandy everywhere else. Link to comment Share on other sites More sharing options...
OrionStang Posted October 19, 2014 Report Share Posted October 19, 2014 Thanks for all the replies, all very helpful! So different vehicles are built with thicker or thinner metal and some are more susceptible to SPL? Makes sense.... I have always thought SPL was measured in Db's but now see there is a little controversy on this. So to sum up RainStrykes post, "Also remember that the sound pressure (the thing that causes flexing) is not the same as decibels.", Is this true or false? That would explain why the car flexed more, while not producing as much sound to the ear-o-meter. All making a lot more sense to me now though, relatively new to the SPL side of car audio, have always had SQ setups (500-600RMS) and flexing wasn't so much of an issue, lol RainStryke is the last person you want to take advice from. The quoted statement is wrong. He then tried to justify his answer, ans sound smart, by saying he left a word off a term. Sound pressure is measured in decibels, whether or not "level" is added after sound pressure or not. Flex is all vehicle dependent. My car hardly flexes at all doing a 148 at 32hz. Some cars are simply structurally weaker. Flex is a very poor gauge of loudness. SMD Super Seller My Feedback Thread Link to comment Share on other sites More sharing options...
RainStryke Posted October 19, 2014 Report Share Posted October 19, 2014 SPL is translated from PA. PA is a unit of pressure. Decibles are a unit of sound. They are not one in the same. Link to comment Share on other sites More sharing options...
kingdragon Posted October 19, 2014 Report Share Posted October 19, 2014 Usually hatchbacks are louder and especially small ones as they have limited space and sound like hell. SUVs also are loud but usually they have more space so you need more subs or more powerful subs. Sedans on the other hand also can be very loud but when subs facing inside the cabin and not on the back as it rattles a lot and when there is rattle you lose SPL. Now let's see why walled cars tend to be so loud. Imagine having a car with a cabin only 1.5 meters....it's almost the same thing as the wall is very close to the windshield and only some cms behind your head. What is produced is very close to the body and you feel it straight away. Link to comment Share on other sites More sharing options...
alaskanzx5 Posted October 19, 2014 Report Share Posted October 19, 2014 SPL is translated from PA. PA is a unit of pressure. Decibles are a unit of sound. They are not one in the same. You go to competitions where they measure your spl in units of decibels. Sound presure is what they measure, decibels is the unit used to express the level of pressure. Its isn't necessarily only the size of the vehicle that makes a difference but also the shape and materials used. Remember as well that it takes a measured distance for different freq to fully mature as I have seen it called. There is a way to figure it out but I don't know it or an example of it. t1500bdcp 2 t2d4 15" 1 t600.4 1 t400.2 1 set p1 tweets singer alt, tons of wiring, smd vm-1, 80prs, back seat delete, still in the works, aiming for a 145-147 with the ability to play 25hz up to 50hz. Link to comment Share on other sites More sharing options...
Uriahia Posted October 19, 2014 Report Share Posted October 19, 2014 Their is an Impala i think it's an 04 or 05 a guy has near me and another guy with a Jeep commander both have the same Kicker set up but the guy with the Jeep his sound pressure output ear wise always stays the same but the guy with the Impala his car seems lower then louder at time i never knew why untill i seen him let his rear seats down and then back up. Link to comment Share on other sites More sharing options...
Guest Posted October 19, 2014 Report Share Posted October 19, 2014 his sound pressure output ear wise always stays the same Link to comment Share on other sites More sharing options...
Souldrop Posted October 19, 2014 Report Share Posted October 19, 2014 Ok rainstryke learn something before you start spouting off false info. It's good you're trying to help, but sometimes spreading false info is way worse than not giving any input at all. http://hyperphysics.phy-astr.gsu.edu/hbase/sound/db.html SPL is not derived from a Pascal. Matter of fact it may be more correct to use the term Sound Intensity Level. A Pascal has units of Newton per unit area. Newtons (kg*m/s^2) / Area (m^2) = Pascals (kg/m/s^2). A decibel is more of a measure of relative intensity and doesn't have any inherent base units. Similar logarithmic scaled are used to measure luminosity, earthquake magnitudes, etc. 1997 Lexus ES300 HU - Pioneer MVH 7350 Processor - Helix DSP Front Stage - JBL P660C Mid/high amp - Alpine PDX-F4 Subs - 1 IA Death Penalty 12 Sub Amp - Cactus Sounds PF300.1 Link to comment Share on other sites More sharing options...
noobslayer77 Posted October 19, 2014 Report Share Posted October 19, 2014 There's really no way to know without a meter. bottom line. My friend had a 13w7 in his subaru hatch, and it shook his rear view mirror off and his windows and windhsield flexed like crazy. His was in a sealed box. I got 2 in my jeep liberty in a ported box, and it flexes my windshield and windows and doors a little, but not nearly as much, but its easily twice as loud. Also put a 15'' on 1500 watts in my buddies civic coup. his windshield also bounces alot, but is no where near as loud as my friends hatch with the w7. The only way to know is the meter. its impossible to gauge it based purely on flex. It ultimately comes down to the quality of the build. also remember that some people who don't have a ton of flex, but are really loud have tons of dynamat and sound deadener in the car. flex doesnt equal high DB 2004 Jeep Liberty Limited 2 13w7s skar 3500 cnf mids (soon) xs batteries Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.