New install of woofers and it sounds terrible.....help

unless i am missing something.... per RF website, you should be running those subs in a box with a total internal volume of 0.46 ft^3. Running them in a 0.7 ft^3 box will push them down to a frequency (plus the wattage) that will cause the subs to operate past their max excursion limits. this will also give you a lack luster performance as you are expeirencing now.

 

Vented option:

 

The box is too big... make it for the exact size required.
i usually set my sub amp filter at about 70-80hz with a 12db slope. if i had speakers for mid bass only, then i would adjust the sub amp to even a lower freq.

 

The Rockford Fosgate tech said the specs listed on the website for .23 ft^3 sealed was a minimum requirement. I told the tech my exact setup and .35 ft^3 per sub was not an issue when we were discussing the poor output I was getting. He said less air space would make the subs more "punchy" and not drop as low. A bigger box with the appropriate amount of wattage for the increased air space would allow the subs to drop lower in frequency.

Update on this subject: Due to complete frustration, I took Rockford subs and amp out, installed the Image Dynamics ID8 with vented box and installed the Precision Power amp. With the seats up, this little system is loud, clean, and has decent SPL for a single 8" woofer. I truly feel that the Fosgate amp may be the problem. It is just weird that the gain is less than 1/3 before serious distortion takes over. I think my Rockford Fosgate days over and I will simply keep the current ID8 and PPI amp because I am getting the overall SQ and volume that is sufficient for me.

 

For the old school brands...basically need to stick with the better and best lines... So either Punch or Power for RF.

These base level amps just about reach distortion as their rated power becomes reached.. So a more expensive amp will sound louder at a lower power than a cheaper amp at a higher power... It's a really strange correlation. Watch amplabs on youtube to see what I mean.

I think with old school power, you generally got 25% to 50% more power than what you paid for before distortion. With today's amps, your getting exactly the 500 or 600 watts you pay for, which immediately teeters at distortion. There might only be 5% to 10% headway, which isn't really noticeable.

I also checked the THD and SNR ratings for that amp, from the manual... It's not bad by any means on paper, I just think the manufactures have it figured out how to run the CEA 2006 tests for best ratings. And car audio is more niche now than ever, And you don't really have anyone smart or willing enough to challenge the ratings at a class action level. These manufacturers are honest with the top of the line amps... But not so much with the entry level amps.