Real difference between one or two 12" subs
08-08-2010, 10:43 PM
#12
I am the different person to these guys, I dont believe 2 twelves is louder then 1 12 exactly. I found with every system i have ever had in my vehicles that a single woofer has always been louder FOR ME. gives me way more options for boxes and sizes, and on the mic my systems have 100% always been louder with a single sub.
Also I had a 12 or 15 farad tsunami digital cap, and to be honest it did nothing so I sold it!
Also I had a 12 or 15 farad tsunami digital cap, and to be honest it did nothing so I sold it!
08-08-2010, 11:32 PM
#13
Thanks for the feedback everyone.
As for the 2 farad cap, why should I get rid of it? If I power the subs to their peak RMS 800W as well as the 40W x 4 for the speakers. that's almost 1kW, which I think requires at least 1 farad. Can someone give me a good enough technical explanation for why the cap is useless/ I would love to get back my $65 and spend it on upgrading my sub amp to 800W instead of the 500W its being powered to now.
I have used the program WinISD and the EBP of the subs are 28.8 and, usually, under 50, its strongly recommended to go with sealed or 4th order. I simulated both setups and the 4th order gives a better response from 40Hz to 60Hz, although it drops off faster after 100Hz.
Perhaps I should seal one and 4th order the other? Or port one and badpass the other?
Thanks,
Mike
As for the 2 farad cap, why should I get rid of it? If I power the subs to their peak RMS 800W as well as the 40W x 4 for the speakers. that's almost 1kW, which I think requires at least 1 farad. Can someone give me a good enough technical explanation for why the cap is useless/ I would love to get back my $65 and spend it on upgrading my sub amp to 800W instead of the 500W its being powered to now.
I have used the program WinISD and the EBP of the subs are 28.8 and, usually, under 50, its strongly recommended to go with sealed or 4th order. I simulated both setups and the 4th order gives a better response from 40Hz to 60Hz, although it drops off faster after 100Hz.
Perhaps I should seal one and 4th order the other? Or port one and badpass the other?
Thanks,
Mike
Do the BIG 3. Run some 1/0 wiring. Use the cap if you choose. 1.8-2 cubes per woofer @ 36hz. Money back guarantee from Jalat Designs
08-09-2010, 11:51 AM
#14
0 Watt CAFz'r
Thread Starter
Join Date: Aug 2010
Posts: 11
-Mike
-Mike
08-09-2010, 12:20 PM
#15
500 Watt CAFz'r
Join Date: Oct 2009
Posts: 730
Well we have this:
With this as an answer:
And then we have this......
OP, you have a competitor giving you sound advice that's first hand, not speculation. So you are faced with a choice... Would you like to sacrific performance? Build whatever box you want. If you don't mind sacrificing space, run Jalats box and be happy with the performance. Up to you 
With this as an answer:
08-09-2010, 12:32 PM
#16
50 Watt CAFz'r
Join Date: May 2007
Posts: 384
If your not willing to do the big three, asking for trouble. You can do the big three with 4 guage if you like. For you're proposed system it will be sufficient. You will most likely be louder with the one sub because the mrp-500 will power one sub perfectly and if your only willing to give up 89L of displacent. Generally speaking the larger the box the louder.You should stick with a regular ported box as bandpass boxes are peaky(very loud in a small range of frequency) As for the cap I would ditch it. All a cap does is keep the voltage staple to a certain point. They take 5 times longer to charged than to deplete, so once it's used up(usually 10-15 seconds) it becomes yet another draw on the system. The only real way to do it is upgrade the big three(a must in efficient car audio)upgrade the battery and upgrade the alt.
08-09-2010, 12:49 PM
#17
500 Watt CAFz'r
Join Date: Oct 2009
Posts: 730
^^^
Agree with everything but the cap bit... Caps discharge as close to instantaniously as possible and take 5-6 seconds to recharge from a completely flat discharge (not going to happen when it's running). Because this isn't SPL, it's music, we're not dealing with single frequency tones, the demand on the system will fluctuate, and so will how the cap reacts. Bottom line is the draw on the system isn't significant enough to worry about at this level. I'd still ditch it and upgrade the alt, but in this case I guess it'll make a pretty bandaid....
Agree with everything but the cap bit... Caps discharge as close to instantaniously as possible and take 5-6 seconds to recharge from a completely flat discharge (not going to happen when it's running). Because this isn't SPL, it's music, we're not dealing with single frequency tones, the demand on the system will fluctuate, and so will how the cap reacts. Bottom line is the draw on the system isn't significant enough to worry about at this level. I'd still ditch it and upgrade the alt, but in this case I guess it'll make a pretty bandaid....
08-09-2010, 01:29 PM
#18
0 Watt CAFz'r
Join Date: Aug 2010
Posts: 10
Human percieved 2x loudness is closer to 10dB. Frequency response intensity uses +/- 3dB as a reasonable deviation in output that would be detectable to humans, as 3 dB is considered an amount of change less than which is not easy to detect, more than 3 db is perceptible by most. Obviously, to each person it may be somewhat different depending on their hearing and auditory system, but generally 10dB is considered 2x as loud to the human ear. Go to this link and check it out...it's simple and will clear things up.
http://trace.wisc.edu/docs/2004-About-dB/
http://trace.wisc.edu/docs/2004-About-dB/
08-09-2010, 02:02 PM
#19
I don't want to change the battery or upgrade the alternator and I want to use gauge 4 wire. Also, 1.8 cubic feet times 2 is 102 Liters, and all I am willing to give up is 89L, not including the walls. WHat enclosue design dhould I use? Right now I am powering both these 400W rms subs (800 total RMW) with a MRP-M500 at 500W rms, so I don't want to put any added stress on the amp by putting the subs in a sealed enclosure. My only other options are 4th order, which is still technically sealed, 6th order, which is too difficult to porperly build as an amature, or vented/ported. I can invest an extra $120 and get the MRP-M1000 (1000W rms), but then my whole system will be 1200W rms, and then I'd be really pushing the limits of the electrical on a car that I refuse to do the BIg 3 on.
-Mike
-Mike
-Mike
-Mike
i hope you know that proper 4th and 6th orders are like 2 times the size of ported enclosures.
you do what you choose. its your car. if its space you are worried about, then sealed might be your only choice. in that case, that woofer seemed to like 1.2 cubes sealed, stuff with some polyfill (only about 40%) (can be obtained at fabricland)
