Basic questions

[n2audio 5,000+ posts]

You have an 80A alt and an amp that will try to draw well over 200A at high volume. Once the alt is maxed out (at ~14v) it will begin drawing from the battery at ~12.5V. Since it's pulling 100A+ from the battery that 12.5 will drop fast - to 10-11 that you're seeing. Higher quality amps with better protection will shut down in those conditions to reduce the chance of being damaged.
So you have at least two significant problems. 1) you're pushing your alt to its max anytime your amp's at ~1/2 volume or more, 2) you're starving your amp of voltage it needs to produce the power it's trying to produce - this in turn requires it to try to draw extra current putting it in a cycle of heat and inefficiency. 3) you're tapping into your battery's reserve a lot more than it is designed for reducing its life and available current to start the engine.

The good news is -- HO alts for older Hondas are not expensive. You can get ~200A alts on ebay for ~$200.

Not that it matters at this point, but you don't want your bass eq setting cranked up. You're bloating the sound at 45hz, clipping at 40-50hz at anything over ~1/2 vol, and making everything else quiet in comparison.

 

[audiobaun 5,000+ posts]

You might take a look at my sig on the Honda CVR I had. I think it is still present.I did the Big 3 with 2ga, and ran 2 ga power wire( all I had and used as I was not spending very much on my work vehicle and used gear I had lying around).Placed a group 78 Orileys AGM Super Start under the Hood and Placed another in the rear (ran 2ga to rear batt, and drilled a hole and grounded to the rear axle frame.Distro block at that Batt, and a Ground Distro block there for the amps and fans.Used Old School Amps(current hoggs) and did just fine on the existing 80 amp alt. I did end up doing the ELD Bypass to keep my voltage stable rather than jumping from 14-down to 12 when the ELD kicked in. There was a thread that Keep_Hope_Alive had in order to do that Bypass for the ELD. For approx. 1700 RMS on the sub stage on a pair of 10s running at 2 Ohms at 32 HTZ, and 200 rms on front stage, it was all I could do to keep the roof in tact.Didnt want to try at a 1 ohm load on subs, Wasnt necessary and didnt want anymore current draw. Ran 2 ohms on sub and 2 ohm on mids and highs. I doubt that that Hi-Fonics would surpass that Matts 300 output. Id try 2 good AGMs( Dont mix different batteries) and set it up properly/ wire it up properly, and get a properly Tuned enclosure built for those subs will make a difference.If Not buying a HO Alt, Id recommend getting rid of that Hifonics amp and buy a more efficient amplifier set up as well over all with batteries. DO NOT BUY THOSE TURD ALTS OFF OF EBAY.You will run the risk of ruining your batts and as well as some gear if that alt starts to go bad.It will be a very expensive lesson. ... Just My 2 Pennys

 

[audiobaun 5,000+ posts]

Adding another to this thread you have here. Sounds as though you do not have the experience to be under the hood let alone doing any type of electrical work on the car in general.Id recommend that you find someone on this Forum that has a little bit of knowledge that lives near and willing to help out for some lunch, and maybe a few beers before you begin to FRY and LOOSE Gear and maybe even Flame that Car up.

 

[ThxOne Premium Member]

A visual for you O.P. The only other thing you may want to do is add a second battery in the rear. Like a group 31AGM.

 

[tommydh 10+ year member]

View attachment 21443

Turn your subsonic filter to 12 oclock to start, LPF same. What head unit are you running? Your gain is way off that should be closer to 12oclock also. Big 3 wire upgrade is def needed, and a better battery.