[smongklong]

Hi Team,

Can someone point me to the best guide/tutorial on how to use an RTA in attempting to flatten frequency signals? Something that people with very limited knowledge like me would understand.

I have an Audison Bit Ten installed in my car and have been playing with it and using just an RTA app. I'm comparing it to the initial tune i got from the shop and my results are completely horrible (sounding like tin can).

What i don't understand is when i use an app (android phone) with just the built in mic, the signals across the frequency band hovers in the -50db range. In the shop when they RTAd it with an old school analyzer, it was showing in the 0db (+/-6 to 12 db range). Why is it different?

I have hertz hsk 165xl in fronts (passive crossover) powered by audison sr4 bridged. high pass filter at 70hz in a 12db slope
I have hertz dsk 690 for rear fills powered by hertz hcp2 band passed at 2.5k hz/ 70hz
my sub is an audison av10 with hertz hdp1, low pass filter at 70hz in a 24db slope.

I've been trying to learn how to equalize so I can be independent and not reliant to shops trying to scam me for tuning fees.

your feedback is very welcome and would help me with my sanity. kindly point me in the right direction as well where i can find this great tutorial.

thanks.

 

[jdsoldger]

The difference in level is likely because the shops system is referenced to a level they chose and set as 0dB. Decibels are always in reference to something else and are not a defined unit of measure. Where the reference in your phone is set is entierly different.

The other thing you need to know is that your phone's microphone is likely optimized for human voice, being most sensitive in the 500-4khz range and dropping off either side of that. Even the good ones I have seen are useless above 10khz. To really tune using an RTA, you will need a proper calibrated (or close to it) microphone. These can be made if you are handy, or useable USB ones can be had for ~$80.

There is also the option of learning what a proper frequency responce sounds like and tuning by ear. This takes practice though.

 

[troutspinner]

Here is a link to a thread made here by Hanatsu. http://www.diymobileaudio.com/forum...first-timers-guide-measuring-your-system.html

It is one of the best resources I have come across learning how to tune with REW and a Calibrated Mic. If this is something you want to get into, this thread might be a little over your head at first glance but with some google, youtube and searches here it will start to click.

IMO, learning how to use REW and how to apply it to tuning a car audio setup was invaluable for setting up my system, it will also be a huge help for anything I get into down the road.