Gain Setting Tutorial

[jharijan 10+ year member]

nah, I don't use a bass remote aside from the bass on my HU but i've heard that once you set the gain its not such a good idea to use that, is that accurate?

another thing I was wondering about is how to accurately set my subsonic and low pass filters. I know that the ss is supposed to be like 5-10 below the frequency of my box but not so sure about the lp. The knobs for both of these are numbered only for high and low but no where in between so I'm not sure how to set it to the exact number. this is what I mean...

http://www.mtx.com/caraudio/products/manualsQuickInstall/amps/XT_600XD_300XD_InstallSheet.pdf

 

[MikeyF 10+ year member]

So, I'm really kinda confused. You don't want to turn the bass boost up on the amp at all?

 

[halfwaytohell 10+ year member]

so im aiming for 900 rms at one ohm. with a 50 hz test tone should my bass level b at 50 65 or 80 on my deck? next if im right i should see 30.00 on my dmm? i all so heard if u dont have your subs/speakers wired up when you do this the number that you come up with in my case 30.00 will b way off. i would b sending less then 900 more like 600rms or so cuz of the rise you will see when you have your speakers/sub connected to your amp.any truth to that

 

[halfwaytohell 10+ year member]

ttt

 

[halfwaytohell 10+ year member]

bump

 

[halfwaytohell 10+ year member]

lets get my question answered

 

[1rockford1 5,000+ posts]

i got 31.4 but that was only at volume 20 or so. most of the time i listen to it at 25-28. i kept geting a nasty buzzing sound if i went louder on my volume. i guess my speakers dont lilke 50hz test tones lol. so i lowered my gain a tad what u guys think? i was tryin to get about 900 rms to my sub.

 

[thegreatestpenn 5,000+ posts]

made a vid for this since I still see a ton of people setting gains wrong. Any and all improvements i can make let me know

 

[Ellsworthz 10+ year member]

good vid ^

so If my amp is rated at 1500rms @ 1 ohm and lets say I want to use 1000rms.

it would be the sqrt of 1000, which is 31.6 so thats what my multimeter should read when playing a 60hz tone?

also should I use a 60hz tone at 0db? or do you use 60hz @ -3db?

 

[surrealmethod 10+ year member]

made a vid for this since I still see a ton of people setting gains wrong. Any and all improvements i can make let me know

Video helped a ton.

When my amp comes in, I will be following this.

Thanks!

 

[Haunz 10+ year member]

made a vid for this since I still see a ton of people setting gains wrong. Any and all improvements i can make let me know

Still wrong.

Having a load hooked up will change the rail swing considerably, and so you should most certainly have a load hooked up to the amp! Otherwise what you are doing is pointless...

Otherwise looks good...

 

[surrealmethod 10+ year member]

Still wrong.
Having a load hooked up will change the rail swing considerably, and so you should most certainly have a load hooked up to the amp! Otherwise what you are doing is pointless...

Otherwise looks good...

So follow the vid except with my sub hooked up?

 

[Haunz 10+ year member]

What I would do is use a non inductive dummy load that is approximately equal to the subs DCR at a working temperature... but thats me... having your subs hooked up should be close enough...

With that said gains really should be set by ear... perhaps with a scope or THD analyzer to make sure you arn't overdriving things... speaker workshop is a free program and can be used for such things...

 

[Tek18 10+ year member]

i have been briskly been looking through this thread and have yet to see something about setting sub to 28hz and the other to about 80hz max, i have my 31.5V for my main gain correct i just don't know where to hook up my DDm for the other 2 as it reads the voltage?? confused...

 

[Tek18 10+ year member]

"

Setting the subsonic filter (if available):

1) Determine the tuning frequency of your enclosure (if using a sealed enclosure, turn SSF off or to minimum frequency)

2) Calculate the desired SSF frequency by using the formula: SSF = Tuning*3/4

3) If number is not whole, round to the nearest integer

4) Write the SSF frequency down

5) Calculate the desired SSF voltage by using the formula: SSF_Voltage = 0.707*Sub_Voltage

6) Write the SSF voltage down

7) Turn the SSF to the maximum frequency

8) Set track to the SSF frequency and set to repeat track

9) Set to volume written down in speaker setting stage

10) Turn down the frequency on the SSF control until you reach the SSF Voltage from step 6

11) Turn the volume down to 0

Setting the low-pass filter:

1) Turn off the head unit

2) Unhook the multimeter from the sub amp

3) Hook up the speakers and sub(s)

4) Turn the low-pass filter on. If your HU and amp both have LPFs, use the one with the most flexibility (continuously variable > selectable > fixed)

5) Turn the LPF frequency to the minimum frequency

6) Insert music you’re familiar with

7) Turn the volume up to a comfortable level

8) Turn up the LPF frequency until one of the following is true: the sub stage and speaker stage blend perfectly, you can tell the bass is coming from the rear, or the bass starts sounding weird. If the latter two, use the highest setting before audible anomaly.

9) Turn volume down to 0 and turn off head unit

"

all seem to be by ear, is there a way to set it exact with the DDM?