Amplifier Tuning

ravi.rajan · 02-19-08, 10:14

Hi,

Need some help in tuning my car audio system.

Have an ALPINE 9887 HU with JBL GTO5355M 5 Channel App and Polk Momo series components, mid range and subwoofers.

Would like to know on how to exactly tune the above systesm (focus on crossover settings on HU and amplifier input level/cross over settings will help)

Thanks,
Ravi

Brandon1 · 02-20-08, 08:10

When you start, make sure everything is installed properly. Make sure everything is in phase. Make sure all eq is set to flat, and soundprocessors off. Make sure all crossovers are off. Burn a cd with a 50hz tone. (Realm of Excursion) Then disconnect all of your wires leading to your speakers. Get a Digital Volt Meter. Then you have to do some math. Take the output to "ONE" channel of the amp (example, if I have a 50x4 amp, take 50) and then multiply it by how many ohms it will be running. ( Example, if I have a 50x4 (rms) amp that runs at 4ohms, multiply by 4). Then take the square root of that number. That will be the voltage that you will be looking to get from the amp.

Now hook up the+ and - to of the volt meter the corresponding terminals on one channel of the amp. Put the cd in and turn it to 3/4 volume. now slowly raise the gain on the amp until the # you got from the math problem, matches the # on the volt meter. Then set all other speakers in your system that same way.

For crossovers, I always use the crossovers on my h/u. I generally go with 80hz highpass at 18/db octave for front speakers, and 80hz low pass at 24db/octave for subs. DONT turn on the bass boost, or BBE or any of that junk, that just mixes signals and makes it sound worse.

Your system should sound pretty damn good after that.

Kinda odd first post for a "detailing forum"

malec · 12-03-08, 03:04

Hi,
I am french so sorry if my english isn't perfect...
I've bought 2 Alpine SWR-1242D in a vented custom fiberglass enclosure.
I tuned the enclosure at 35Hz with the diameter and lenght of vents.
I have a 10 Farads Power acoustik cap and a Lanzar Vibe 266 amp.
My question is : how can I tune the Low Pass filter on my amp ?
Have I to tune the low pass filter at 35 Hz ?
I ask you this because I readed that it was forbidden to tune the low pass filter above the tuning frequency of the box...
Thanks for your answer

ezemsm444 · 12-03-08, 05:12

Hi if you tuned the ports to 35hz the subsonic filter on your amp should be realtively close to 35hz. Due to the port you increase sound intensity starting at 35hz and up (theoretically). anything lower than that can overextend your subwoofers since it will act like if it was in a free air enclosure.

Besides that, the dvom is always the best way to go. Although while setting the gain it is much easier to use acouple of test tracks like 50hz for sub gain, 500hz for midrange, just make sure they are at absolute zero with no added dbu's. since they are playing at one frequency with the same amplitude, it is much easier to set the gains because the voltage will be constant. set that as about 2 tick marks or volume marks before maximum to give you alittle play. Also when using a dvom for this step check to see if it is true rms or not. true rms will give a faster reading response as a regular dvom will give an average.