Very little bass out of my subs...what is wrong!?

[critical 10+ year member]

I just transfereed my system. It is 2 12 inch dual voice coil RE subs with a pioneer 760 watt amp on a pioneer head unit. I jsut moved it to my new car and left all the options the same on the amp like bass boost and gain. They are wayyy worse quality and quieter than before. The only things I can think of are:

1) i blew some fuses and replaced them with smaller fuses than before, does a fuse limit what power goes to the subs or just blow if there is too much??? would bigger fuse = bigger sound?

2) i have positive/negative wiring hooked up backwards (each sub itself has a positive and negative wire coming out of it and i dont remember if square wire is positive or if it's negative..would htis have an effect on output??)

3) any suggestions ???

thanks

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[Rattlebrain 10+ year member]

1) no

2) not unless you rewired your subs wrong.

3) Cabin gain could be an issue

 

[morgans432 10+ year member]

check your speaker wiring same thing happened to me.

 

[critical 10+ year member]

1) so if i wired the neg and pos wrong which i think i did....i would still get sound it'd just be distorted and not very much, right? cuz that could be a problem

2)cabin gain...what is that

3) ill check all my wiring but what am i specifically looking for...the pos/neg swtiched around?? and could it be my wiring internally inside my subs...like not the pos/neg coming out of the box but the 4 wires that connect to each sub itself within my box? ? ? that would be bad i forget how to wire those..i dont understand what ohms is and a long time ago some guy gave me a diagram to wire those too and i did undo them since then but i thought i put it back the right way....

 

[Rattlebrain 10+ year member]

http://www.caraudiohelp.com/newsletter/cabin_gain.htm

The Effects of Cabin Gain in Car Audio Have you ever wondered why car audio systems can have so much bass as compared to a home stereo system? The reason has to do with space. Your home has a lot of it and your car audio system doesn't. Because there is so little space in a car the bass notes (which are long waves) build up inside the passenger area. To calculate the length of a sound wave you divide the speed of sound (in feet per second) by the frequency. At sea level, the speed of sound is approximately 1,127 ft/sec. For example, a 40 Hz note has a wavelength of approximately 28 ft (at sea level).

(speed of sound)/(frequency) = wavelength

OR

(1,127 ft/sec)/(40Hz) = 28.175 ft

Since the length of the average car interior (including trunk) is in the 12 ft range the 40 Hz note will be longer then the car's interior. This is why notes below 70-90 Hz (depending on the vehicle) will have a greater output than the rest of the frequencies. Once this magic frequency is reached, bass output will increase by about 12 dB/octave below that frequency. This phenomenon is called cabin gain or "transfer function". So a smaller vehicle will have a greater cabin gain and should be able to have greater low bass than a larger vehicle. This is true for identical subwoofer systems with identical power. However larger vehicles are able to fit more subwoofers and amplifiers and so can out produce a smaller vehicle with limited space.

The transfer function works well because human ears are less sensitive to low bass. This natural bass boost helps to compensate for this. It doesn't matter what type of vehicle you have, the cabin gain will still apply. It will just be at a lower frequency with larger vehicles and at a higher frequency with smaller vehicles. Firing orientation of the subwoofer system has no effect on the transfer function of a particular vehicle. You can face the woofers in any direction or place them anywhere in the vehicle and the gain will be the same because it is only dependent on vehicle size. This is not to say that firing orientation or woofer placement will not have an effect on the subwoofer system output. It certainly does but this difference is not attributable to the cabin gain.

Bottom line: The cabin gain or transfer function will increase the low bass in a car stereo system over that of a home stereo system. The smaller the vehicle, the greater the gain

 

[Rattlebrain 10+ year member]

1) so if i wired the neg and pos wrong which i think i did....i would still get sound it'd just be distorted and not very much, right? cuz that could be a problem
2)cabin gain...what is that

3) ill check all my wiring but what am i specifically looking for...the pos/neg swtiched around?? and could it be my wiring internally inside my subs...like not the pos/neg coming out of the box but the 4 wires that connect to each sub itself within my box? ? ? that would be bad i forget how to wire those..i dont understand what ohms is and a long time ago some guy gave me a diagram to wire those too and i did undo them since then but i thought i put it back the right way....

http://www.rockfordfosgate.com/rftech/woofer_wizard.asp

 

[critical 10+ year member]

thx how do i know what ohms i want

 

[Rattlebrain 10+ year member]

Depends on your subs VC configuration as to how you can wire it. Cant tell you what you can do without knowing what you got!

 

[critical 10+ year member]

2 12 inch RE RE series DVC subs

2 of these:

12”

Electrical Q Value -Qes: 0.42

Mechanical Q Value -Qms: 4.27

Total Speaker Q Value -Qts: 0.38

Free Air Resonance -Fs: 20.0 Hz

Equivalent Compliance -Vas: 182 liters

One-Way, Linear Excursion -Xmax: 12 mm

Efficiency -SPL 1W/1m: 87.3 dB SPL

Effective Piston Area -Sd: 500 cm^2

DC Resistance -Re: 3.2 ohm

Nominal Impedance -Znom: Dual 4 ohm

Thermal Power Handling -Pe: 175 W

Force Factor -Bl: 15.4

 

[Trey803 5,000+ posts]

check your ground

 

[Rattlebrain 10+ year member]

2 12 inch RE RE series DVC subs
2 of these:

12”

Electrical Q Value -Qes: 0.42

Mechanical Q Value -Qms: 4.27

Total Speaker Q Value -Qts: 0.38

Free Air Resonance -Fs: 20.0 Hz

Equivalent Compliance -Vas: 182 liters

One-Way, Linear Excursion -Xmax: 12 mm

Efficiency -SPL 1W/1m: 87.3 dB SPL

Effective Piston Area -Sd: 500 cm^2

DC Resistance -Re: 3.2 ohm

Nominal Impedance -Znom: Dual 4 ohm

Thermal Power Handling -Pe: 175 W

Force Factor -Bl: 15.4

http://www.rockfordfosgate.com/rftech/woofer_wizard.asp?submitted=true&woofer_qty=2&woofer_imp=4

 

[Rattlebrain 10+ year member]

Use the 4 ohm configuration unless you are SURE your amp is one ohm stable.

Are you using a mono block amp or bridging two channels?

 

[critical 10+ year member]

Awsome thanks. What do you recommend out of those 2 diagrams, the 1 ohm load or the 4 ohm load?

 

[Jdizzle 10+ year member]

do the 4 ohm load the pioneer isn't 1 ohm stable......trust me lol

the 760 is a 2 channel i beleive if so just wire each sub to 2 ohm and run them off each channel....or bridge it at 4 ohms either way...but if you go down to 1ohm youll be seeing ALOT of clipping lol

 

[critical 10+ year member]

haha ok thanks a lot guys ill try all of this tomorrow or tonight and reply back tomorrow night to let you know if it worked. thanks again