Customer Ratings & Reviews

WOW, very good performance

Origionaly intended to use the amp for my components but I ran out of money for toys so I am now stuck using this amp to power 2 Dayton Audio 15" reference subs temporarily. The subs are severely underpowered however they still sound fantastic. The birth sheet that came with the amp rated it at 'nearly' 500 watts RMS. Even when driving the amp at its peak output the distortion is minimal (would still not recommend it though). The only problem I have at all with this amp is that Punch EQ 18db adjust knob (only bass control knob that is compatable) can only adjust the rear channels. Not a big deal, I wouldnt use it anyway if it was on the components. The heat dispersion plate works well but if you have it in your trunk with no air circulation it will still overheat after about an hour IF running near full power.

For my ratings,

Value - was a 5 because Sonic Electronix has some of the best prices I can find from a higher end online dealer and I paid less for this amp than I would have for 400 RMS watt at walmart (not sure if walmart even knows that they are supposed to rate an amp at RMS not peak)

Look/design - 5 because I like simple asthetics, I dont need a bunch of flashy lights to show off since the only people that care about that are usually the people that dont know anything when it comes to stats and what the thing is for. I would rather show it off to people for its sound quality

Durability - 5 because I run it as close to full power as I can without getting distortion and it has no problem.

Features - 4 only because you cannot control all channels using the Punch EQ knob. They do make a bass control knob that will do that however it is not compatible with the Power series.

Ease of use - 5... plug and play (maybe adjust the gain and boost level a little bit but it sounded great right from the factory.

Amazing power output

Received my amp yesterday and I'm using 4 channel 4ohm output for components. The birth sheet has the power output at 85 whats x 4 @ 4ohm. That's amazing. Sounds great hooked up to my front and rear door type-R components. I couldn't be happier with my purchase. Sonic had this product at my doorstep the next day after ordering.

im in love!

As soon as i hooked this amp up to my component sets and they are amazing great power! i had my speakers hooked up to a 4 channel 600 watt sony xplod amp and there is no comparison.

Good amp for highs.

Once I installed it and tweaked it, I never had to touch it, clear crisp highs. I would reccomend this amp.

Small, powerful, and clean

Huge power, birth sheet says 547w RMS. Incredibly small too. Puts out twice the power my Pioneer 2ch of same size does, and way cleaner too.

Have it pushing my 4 T1682s

Great Amp!

This amp pushes extremely clean power to all 4 channels. I'm running Diamond S600s in the front and Beyma W6 in the rear for mid bass. This amp makes this speaker setup sound excellent. The highs are perfect and the lows are tight and hit hard. I definitely recommend this amp to anyone!

Soooo much power

I bought this amp to power my 4 6.5" door speakers and power them it does. Each speaker is rated at 50 watts RMS at 4 Ohms and I have to turn the gain on the amp way down to keep the speakers from blowing out of the door. The birth sheet shows significantly higher power ratings than is advertised for as well. In my opinion you cannot go wrong with this amp at all.

Good Buy

Makes my interior speakers sound great. Would recommend this amp to anyone.

Beast amps

Gotta say RF has some of the best amps on the market,love the power and sound quality from the RF amps.

Rockford t400

I have the T400 powering my focal 6.5 poly glass, it helps them scream to my satisfaction. I have no problem with the amp getting hot or handling my finger going to the volume .

POWER

What more can be said about RF amps,they're way underrated unlike most other cheaper amps, I have mine powering 3 pairs of tweets and about to be adding maybe 2 more pairs on it. This amp is worth every penny. You get what you pay for.

Rockford Fosgate T400-4

This amplifier continues in the long line of quality products from Rockford Fosgate. With the proper adjusting of the crossovers and gains this amplifier is definitely sound quality oriented. I have this in both of my vehicles pushing components and my midbass and highs never sounded better. I highly recommend this amplifier to anyone considering the T400-4 as an option to run their mids and highs. I rate this amplifier an A++. I have been using this amplifier for over a year.

This amp is great!

Clarity and quality are both achieved with this high end audiophile amplifier. Well done Rockford Fosgate. This a perfect 4 channel amp for amy mobile audio enthusiast.

Fosgate Quality!

As with every piece of R/F equipment I have ever purchased this one does not disappoint. Looks great, performs flawlessly and has never overheated even after extended trips with the system blaring at its fullest setting. I have it running my door and rear quarter speakers. (also R/F) I would have no reservations in recommending this amp to anyone who is looking for quality, value and overall cosmetic appeal. Way to go R/F! Way to go SONICELECTRONIX, you rock.

Great Amp!

Great amp for the price.
Pros:
-554 rms total output.
-83 watts per chan at 4 ohms and enough to handle front and rear speakers. (pioneer component front, rear pioneer 6x9)
-Very great design and durability seems to be very good and rigid.

Con's: - No cons at the moment because amp is functioning as it should be. Will give update review in another year.

Crisp amp with good power

I purchased this amp to push two pairs of component speakers. The amp provides good power and has worked flawlessly so far for 6 months.

Great Amp!!

This is one of the best four channel amps I have ever owned. I also have the rockford midrange speakers. With this amp they sounds great, really loud and very clear!!

Perfect

Just what I expected from Rockford Fosgate, an excellent amp. Crystal clear on 2 sets of component Alpine Type S speakers. Amp was tested at 82 watts RMS per channel which is way more than I expected. I would recommend this amp to anyone who wants big power and clarity.

good amp

Bought this amp to power 6 speakers and does a great job. If your replacing the speakers in your car u have to wire them up to a good amp or its not worth it. This amp never overheats and puts out clean sound all day. Highly Recommend.

Rockford Fosgate 400-4 (Black Box) Amp

This is very nice! Is nice for visible installations and has plenty of power for your speakers!

Beauty and a Beast!

This excellent amp is running my main deck and 4 JL audio C3 component speakers effortlessly. No problems whatsoever, runs cool even after hours of playing. I have it mounted under passenger front seat, which is a shame because it looks too good to be hidden! Only rated it 4 star for now because I've only had it under a year, but I won't be surprised if it outlast me!

Review of the Rockford Fosgate T400-4

One word: Gangster. This amp unit is so universal. The controls and power work perfectly for any system

Great Value

I can Recommend this product to anyone cause it is the best purchase i have made

The best has returned

I have been a stereo fanatic for many years and have had plenty of different type of amps. I had heard a lot about them changing ( for the better) so I gave them a try again so very glad I did cause Fosgate is BACK and better than ever. I love this amp and have it hooked up to focal speakers 6.3/4 in front and 6x9's in the rear in my 01 Monte Carlo SS and believe me it's loud (1500 watts total with subs) and crystal clear and I'm loving it! If you want a great amp consider Fosgate again cause there back.

love it

Have this hooked up to 4 alpine type r components/coaxial speakers. Love this amp but now i gotta upgrade on subs.

Fantastic!

For the price this is a fantastic amp. Actually it is pretty damn good regardless of price. I can't believe the sound quality difference between the T400-4 and my old Infinity Reference 475a. it's like night and day though. I guess you do get what you pay for.

Rockford Fosgate T400-4, T500-1bd

Simply awesome. I've built a lot of systems in my time. I never got it right. They always disappointed me. This time I matched all the components up and the system is incredible. This system was combined with 2 12's and 8 6x9's in a boat. I have no more than $2,500 into the system, but when I crank the system up, it is crystal clear, and has the tightest bass I've ever heard. I can be sitting right next to a guy with $15,000 into his system, and mine just blows it away. No one believes mine cost less than $20,000 when they hear it. Simply amazing with these Rockford Fosgate amps.

T400-4

If you want more for your money, get this amp. Rockford Fosgate gives you more than you need, but why not!

Great for the long run

Its a great amp.... got them all hooked up on 4' 6.5" speakers but it has one small flaw. It has that burning smell coming from the amp. Did some research online its mostly dust collection and other small stuff. Had it for about 5 month now and its still kicking.

amp

I would recommend this to everyone very nice loud soon will buy another.

Rockford T400-4 amplifier is a BEAST

I love everything about the amplifier. My truck always gets compliments. I'm thankful that Sonicelectronix.com had it instock. They're #1 (:
Customer for 16 + plus years

By Andrew A. on April 8, 2026 Verified purchase