Gain?

[The_Councillor 10+ year member]

Back with another question...

Bout to hook my amp up and have been reading up on setting the gain... And again, I'm extremely new to this car audio stuff, but on the amp, there is a Bass Boos level (db), LPS Frequency (hz) and a Input Sensitivity(v).

Which one of these is the gain exactly?

And my second question is about the level I should be setting it at... The subs each have an impedance level of 4 ohms at 300 watts each and the amp is a Kenwood KAC-8105D, which says 1000watts but I've been told it won't do more than 500watts.

So is the target voltage I'm gonna be looking for going to be around 44.721?

Or am I way off on that?

Click to read more...

 

[_S7V7N_ 10+ year member]

Kenwood KAC-8105D

Class D Monoblock Car Amplifier

RMS Power Rating:

4 ohms: 300 watts x 1 chan.

2 ohms: 500 watts x 1 chan.

Max power output: 1000 watts x 1 chan.

MOSFET power supply

LED power indicator

Tuned Bass EQ (0-18 dB bass boost at 40 Hz)

Speaker-level inputs with signal sensing for automatic turn-on

Preamp RCA outputs

Short circuit, DC offset, overload, and thermal protection circuitry

Aluminum die cast heat sink

Speaker impedance: 2-8 ohm

Gold-plated RCA level inputs

Gold-plated screw terminals

Input sensitivity: 0.2-5 Volts

Variable low-pass filter (50-200 Hz, 24 dB/octave)

Subsonic filter (15/25 Hz)

CEA-2006 compliant amplifier

Frequency response: 10-200 Hz

Dimensions: 11"L x 2-5/16"H x 9-3/8"D

4-gauge power and ground leads recommended. Contact us for information regarding a discount on a select amplifier kit when purchased together.

Input Sensitivity will be your " Gain"

LPF is your Low Pass Filter

Then bass boost is your....Bass boost.

 

[VisceralSound 10+ year member]

Your input sensitivity is the gain on that amp.

 

[The_Councillor 10+ year member]

Alright cool, but as far as the target level for the gain, using some formula i found online says,the square root of the, Power Dissipation (watts) X Resistor Value (ohms), and that's the voltage I want it to read on the meter when I'm tuning the amp?

So the power dissipation would be 300 watts

And the resistor value, 4 ohms..since that's the impedance of the subs I'm using.

So I'd wanna try to get a reading around 34.64?

 

[_S7V7N_ 10+ year member]

On the Voltage you'll have to wait.

But i believe you'd do SQRT (500x2)

My math would be the 500 watts RMS

Multiplied by the 2 Ohm load on that amp

You get 1000 - SQRT of 1000 = 31.6

But somebody will be along shortly i'm sure to be 100 percent sure.

You are using (2) 4 ohm subs correct ?

 

[The_Councillor 10+ year member]

On the Voltage you'll have to wait.
But i believe you'd do SQRT (500x2)

My math would be the 500 watts RMS

Multiplied by the 2 Ohm load on that amp

You get 1000 - SQRT of 1000 = 31.6

But somebody will be along shortly i'm sure to be 100 percent sure.

You are using (2) 4 ohm subs correct ?

Ya I'm using 2 subs that are 4 ohms each, but you go by the impedance of the amp then, not the subs?

 

[TheUnderFighter 10+ year member]

You go by the impedance load placed on the amp. If you have your subs wired to present a 2 ohm load on the amplifier that's what you go by. So, Square root of (500x2) = square root of 1000 = 31.6 and that's what your gain should be set to.

As stated before, input sensitivity is gain. Bass boost should be off. or all the way down.

 

[_S7V7N_ 10+ year member]

Speakers wired in parallel

Site to pull up this info : Subwoofer Wiring Diagrams, Two 4 ohm Single Voice Coil (SVC) Speakers

 

[PPD3195 10+ year member]

How would that math translate into a multi channel amp? If you're running a 4 channel amp at 2.7 ohms, and the amp is rated at 120 rms at 2 ohms, 71 at 4 ohms...would you go by the 2 ohm number, 120 watts X 4 = 480, 480 X 2(ohms) = 960. 960 squared is 30.98, so set the gain at 31?