Affects of vehicles on SPL

[F150Matt 10+ year member]

Ok, I've got a question or two. A friend of mine has two kicker comp VR 15's pushed by a Power Acoustik Gothic Series 1600 watt amp. This amp is rated at 740 watts RMS/ 1600 peak. He has these in a ford bronco. Its bigger than a ford explorer as far as internal airspace goes. I have two solo baric L7 12's pushed by a JBL 1200.1 in my single cab F150. Sound wise to our ears anyways, his seems much louder and it also is more noticeable on the body(actually feeling the bass). I always thought that the VR 15's and the L7 12's should be similiar or that the L7 12's would probably beat the VR15's when on about the same power. Both sets of subs were in sealed boxes, about the middle range of the recommended, and I actually had more RMS power going to my 12s. He has not yet metered his 15's but I think his is louder. What are the affects of the vehicle on this? Would my two L7's in his vehicle seem louder than the 15's? Would his 15's in my truck(if the box would fit) seem about like the L7's or maybe less? Let me know. Also shouldn't it be easier to get Sound pressure in a smaller area than a huge one? Thanks.

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[chris229 10+ year member]

Originally posted by F150Matt What are the affects of the vehicle on this? Would my two L7's in his vehicle seem louder than the 15's? Would his 15's in my truck(if the box would fit) seem about like the L7's or maybe less? Let me know. Also shouldn't it be easier to get Sound pressure in a smaller area than a huge one? Thanks.

yes-----it would be easier to get higher SPL in a smaller airspace but there are some other factors involved
1------- displacement of each sub at their power level

2 ------ efficiency of each sub

3 ------ phase placement in the cabin of the bass frequencies

4 ------ size of cabin

 

[F150Matt 10+ year member]

So the size of cabin factor, and the fact that he has his 15's facing the rear of the bronco with me having the solos facing forward could factor into why his seems to hit harder? He's going to a competition next weekend with me, then we'll let the meter decide who's is louder, but to the ear, his seems louder.

 

[Alaxan 5,000+ posts]

Originally posted by F150Matt So the size of cabin factor, and the fact that he has his 15's facing the rear of the bronco with me having the solos facing forward could factor into why his seems to hit harder? He's going to a competition next weekend with me, then we'll let the meter decide who's is louder, but to the ear, his seems louder.

He is also moving much more air space. A 15 compared to a 12 tends to do that. However!, I have seen and even demonstrated that smaller can produce more. I used to run 4 12" subs that put 6 15" subs to shame and on a regular basis.

 

[F150Matt 10+ year member]

ACtually since I have the square 12's and he has round 15's, there is less difference in cone area than normal. What was your secret to blowing away the 6 15's with 4 12's? Power? Box? Different brand of sub? Thanks.

 

[Corsica 5,000+ posts]

Originally posted by Alaxan He is also moving much more air space. A 15 compared to a 12 tends to do that. However!, I have seen and even demonstrated that smaller can produce more. I used to run 4 12" subs that put 6 15" subs to shame and on a regular basis.

care to share what 12" subs did that for ya????//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

J

 

[ramos 5,000+ posts]

Before you go to the comp download some test tones. Then when ya go try a couple different to find your peak frequency. Then crank that frequency. With the small cabin of the F-150. Those L7's should put up some pretty good numbers even in a sealed enclosure. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[ramos 5,000+ posts]

Originally posted by F150Matt ACtually since I have the square 12's and he has round 15's, there is less difference in cone area than normal. What was your secret to blowing away the 6 15's with 4 12's? Power? Box? Different brand of sub? Thanks.

The biggest factor is the enclosure. You can take the best subs in the world put them in a so-so enclosure. And have your a$$ handed to you by somebody with flea market subs in the perfect enclosure for the subs and vehicle. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[drkodin 10+ year member]

could he be having some cancelation problems? i know that in cars, facing the rear of the car and closest to the rear causes the least cancelation. so, since his are facing forward, could it be a problem?

 

[ramos 5,000+ posts]

Could be. Could also be the difference in size of the vehicles. Ever noticed when you rol down the windows your system seems to be louder. Same principle. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Alaxan 5,000+ posts]

Well. I actually had a lesser brand of the same companies speakers. I had 4 12" Orion cobalt series powered by an HCCA250. She had 6 15" Orion XTR series and I forget but she managed to be in the same power class as me. I beleive she was also running Orion amps. I had more air space to move being as it was a 1991 Nissan Sentra two door and she had an extended cab pick up with a truck box that was loaded down. I had a pair of subs in separate chambers from the other pair. essentially I built two boxes and one open enclosure per box. I took away the rear portion of the rear seat and had an open display for my amps and subs and rocked the comp scene that whole year with it.