So my sub blew AGAIN. It’s the third one in 3 years. So I analyzed every area of my system and I figured out instead of giving it about 300 Watts I was pushing closer to 450 to the sub and over time it just blew the voice coils. So I ordered another Alpine Type R subwoofer and before I installed it I meticulously set the gains again. In case you’re u are not familiar setting the gains will allow you to adjust the amplifier input voltage to match the head units output voltage. If this isn’t done correctly you can distort the amps input stage and the amplify the distorted signal which can send some bad stuff to the speakers not to mention just plain sound bad. The problem I had was I set the test tones with an iPhone that may have had a set output level. I then got a new iPhone and a new output adapter that had a variable output. I set the gains at about 3/4 the output volume on the phone. That’s great as long as I don’t run the iphone output hotter than 75% of the max volume. Which I’m sure there were times it was maxed out. This was sending 25% more voltage to the inputs of the amp and them amplified...poof. Speaker blown.
So my solution was to set the gains at 100% volume level from the phone. I used a test tone app to deliver pure test tones at certain frequencies. I connected a digital multimeter to the amp output and measured the AC voltage. I then turned on loudness as well as the bass up to a +3 on the eq. This is my normal listening setting. I also turned the sub channel up to 10 when before my gain was set when it was on 7. I used these settings to adjust the voltage to send out 300 Watts on those settings. The speaker is rated at 350 Watts RMS and 1000 Watts peak. I also set the front speakers gain at those settings to put out 85 watts. That’s what the amp is rated at even though the speakers can handle 125.
App I used for test tones
Settings for setting the gains for the subwoofer
Settings for setting the gains for the mids and tweeters
The results are amazing. I thought it sounded good before but now it’s cleaner and clearer. The low end isn’t muddy like before it’s very defined and punchy. The highs are clear and bright. I actually had to fade the fronts out a bit because they were too bright and it wasn’t balanced. Once I got the balance right it was like butter. Smoooth!