Gain overlap

[GioRF]

Adding gain overlap when setting amp gains is recomended by Rockford Fosgate they recomend a -10 db of overlap for subs and -5 db for fullrange.

My question is what are tha pros and cons of setting with overlap?

[BeachJoshua]

Adding gain overlap when setting amp gains is recomended by Rockford Fosgate they recomend a -10 db of overlap for subs and -5 db for fullrange.

My question is what are tha pros and cons of setting with overlap?

My question is what is gain overlap?

[ib2loud]

Gain overlap is a compensation mechanism to account for the fact that we don’t listen to test tones in mobile audio

systems, rather we listen to music. Test tones are great for setting up the input levels on each component of the signal

chain, but test tones are constant levels all of the time. Music has levels that simply are not constant all of the time.

There are loud passages and soft passages in music, and these are constantly changing. Due to this fact, the maximum

unclipped output levels determined by test tones will seem as if the system doesn’t play very loud. Certainly it’s free of

clipping and audible distortion, but it’s not as loud as it seems like it could be overall. This process allows a measured

amount of increase to be implemented without “guessing” by just turning up the gain controls on a random piece of

equipment. Adding extra gain to the signal chain whether it’s at an upstream signal processor or at the amplifier at this

point is a trade-off of benefits and drawbacks. Most people find that there is a good compromise of these trade-offs

When you raise the gain above the levels achieved with a test tone, you will lower the signal to noise ratio of the

system. In this scenario, the trade-off is higher output at maximum levels trading off for more hiss and system noise

with the volume at lower levels. There is always an acceptable compromise.

Additionally, when you raise the gain above the levels achieved with a test tone, you will increase audible

distortion of the system. In this scenario, the trade-off is higher output at maximum levels trading off for more

frequent moments of “clipping” with both the volume and the music at their maximum levels. Check out the amount

of time that there is added distortion in the signal based on the amount of gain overlap added. Once again, there is

always an acceptable compromise.

Add in 5dB of gain overlap to achieve a higher volume with music (rather than test tones). It’s a safe compromise

between slightly increased distortion (Less than 0.1%) and louder output (nearly 5dB). Less critical listeners could

tolerate 10dB of gain overlap, but look what happens to the distortion increase. Some people will easily hear that with

a great set of mid and high frequency speakers (certainly more evident on compressed audio tracks as well). Reserve

15dB of gain overlap for subs, if at all. If you are using this setting, chances are you can go to a bigger amp for better

sounding results at the same volume levels with less distortion and more headroom.

Use the gain overlap tracks on the RTTI/3Sixty set up disc to achieve the gain overlap safely without causing damage to

the speakers. Simply play the same frequency (HP/BP/LP) as before and increase the voltage levels to the same place

the recorded measurements were at 0dB levels for 5dB of overlap. If you use the 0dB tracks to increase the output

voltages to do this, you will almost certainly damage the speakers if not using load resistors.

Don’t forget to disconnect the speakers when setting up gain overlap!!!!

[Decaf]

0db is for competitors or people who are very scared to turn it up on music, no music is this loud, only sine waves

-3db is good for most people, stuff like Dj Billy E and Bass Mekaniks gets this loud

-4.6db is the test tone i use, it gets the most out of ur amp safely on most music

-5db/-10db RF suggested levels... lots of music is louder than -10db... so i wouldnt use that personally

[GioRF]

0db is for competitors or people who are very scared to turn it up on music, no music is this loud, only sine waves

-3db is good for most people, stuff like Dj Billy E and Bass Mekaniks gets this loud

-4.6db is the test tone i use, it gets the most out of ur amp safely on most music

-5db/-10db RF suggested levels... lots of music is louder than -10db... so i wouldnt use that personally

So where could i find 50hz and 1khz tones at -3dbs and -4.6dbs?