# help needed, adding amp and testing



## 836147 (Mar 10, 2019)

Hi guys, understand how to test and adjust gains using oscilloscope but trying to understand if it is ok to play a 50hz test tone through the system to adjust the gain on my new sub amp. i.e it has the standard factory amp connected and i have used technics add an amp to add a sub and sub amp to the factory system. If i use the normal method of testing to set up and check for gains on the new sub amp, the test tone will play through the other speakers via the factory amp while i'm doing it. Any ideas guys?


----------



## Doug Huffman (Apr 25, 2015)

The 50~ tone is OK unless you mis-match impedances and / or drive it too hard.


----------



## 836147 (Mar 10, 2019)

everything is standard BMW apart from sub/amp, without taking the car apart i'm not sure what the other speaker impedance are, but going from what i can make out on the net, BMW use a range so probably different ohmage speakers throughout. Testing it to test the gain setting on the sub amp requires running at high output so i can work out where to set the the amp gain to prevent clipping (using the oscilloscope) hence the original post. Thanks for the input though.


----------



## Boulderguy10 (Jan 28, 2019)

Nothing wrong with running ANY test tone thru the system, it's just sound. In this instance it sounds like you'd be better off setting the new amp gains using the voltage method with a multimeter - tough to miss that way.


----------



## 836147 (Mar 10, 2019)

*50*



Boulderguy10 said:


> Nothing wrong with running ANY test tone thru the system, it's just sound. In this instance it sounds like you'd be better off setting the new amp gains using the voltage method with a multimeter - tough to miss that way.


Cheers - appreciated. JL say 40.0v for a 4ohm speaker on a JL600/1v2 in the manual, i prefer the oscilloscope clipping method but i'll give the 40.0v method a go. Thanks again.


----------

