Fosi Audio Bluetooth Subwoofer Amplifier 2.1, BT30D Pro Subwoofer Amp with TPA3255 Chips 165W x2+350W & Bass Treble Control, 2.1 Channel Sub Amplifier for Desktop/Outdoor/Bookshelf Speakers

So for people reading this thinking why the glowing review, let me tell you first what my main system is. My speakers are B&W Nautilus 804’s with Nautilus 800 HTM 1 center, 805 surrounds and SVS height speakers for Dolby Atmos powered by a Denon AVR-X4700H. This amp and speakers in no way compares nor could it.For my computer, I bought a Cambridge Soundworks package containing The BassCube 821 and the MC 105 speakers about 13+ years ago. The BassCube has a down firing 6.5” polypropylene woofer (4 ohm) in a sealed box that also contained the amplifier for the three speaker system. The MC 105 (8 ohm) has a 1” aluminum dome tweeter with a 3” midrange in a sealed cabinet. The system was similar in design and appearance to the Klipsch ProMedia 2.1. Unfortunately, my system finally failed after years of service leaving me searching for a suitable replacement for that particular location and purpose. What failed was the amplifier that powered all 3 speakers. The power supply filter caps failed taking out components down line – not worth fixing.I considered the Klipsch ProMedia 2.1 but the long wait time and some reviews mentioning early failures and sound issues made me hesitant. My next choice was the Edifier S350DB which is larger than the Klipsch and my Cambridge system and it too had it’s detractors and is $400. So, I tried the Fosi Audio Bluetooth Subwoofer Amplifier 2.1, BT30D Pro and was blown away by the sound. Connecting it to the MC 105’s was easy as I just needed good speaker cable with with banana plugs at one end for the amp and twisted wire for the speakers. The 6.5” subwoofer speaker I connected internally directly to the existing speaker terminals. I first removed the wires from the internal amp and used two of the four speaker terminals on the back to connect the woofer to the sub input on the Fosi. Then I put all the screws back into the back panel of the subwoofer to close it making a good air tight seal.Previously, the bass coming from the BassCube 821 when it worked was boomy at times and sloppy it wasn’t tight and certainly didn’t go deep. Now it feels tightly controlled, musical and it goes way deeper. It seems to have more synergy with the MC 105’s which also sound more musical to the point that I actually listen to music while working on the computer instead of watching TV. Your mileage may vary based on the speakers you use but at this price point for me at least it was worth the try and I am amazed/surprised at the audible results. The amp has just the right settings to tailor the sound to your speakers and preference. The separate Bass and Treble are mainly for the smaller speakers and have little effect on the subwoofer. For the sub you have SUB FREQ which sets the cutoff point from deep bass going clockwise on up and SUB VOL which together give the ability to tailor the sound to your liking.I bought a power strip that turns on the monitor and the amp when the computer powers up so I don’t have switch it on and off, the TrickleStar TS1104 7 Outlet APS, 1080 Joules, 3 ft Cord White sold on Amazon https://www.amazon.com/TrickleStar-TS1104-Outlet-1080-Joules/dp/B0B61ZCPK6.Now when I turn on the computer everything turns on by itself, the amp and the monitor.So if you have a dead Cambridge or Klipsch system and are handy with a soldering iron or if you have speakers you really like but their current amplification is not so great, give these a try, you might be pleasantly surprised.BTW, I have received nothing in return for this review.All the best:ArtIf you found the review helpful, give me a thumbs up - Thanks!

My goal was to setup excellent sounding backyard garden speakers. First a quick story about what led me to this incredible Fosi amp. I found a terrific "all in one" setup from OSD Audio that was a Bluetooth capable powered outdoor subwoofer with 2 channel satellite powered outputs (can power up to 4 satellites total). I purchased 4 of the OSD Forza 4" satellites, which are AMAZING commercial grade outdoor speakers with separate woofer and tweeter in each speaker. The system sounded great until the speakers and sub started crackling and popping, even when nothing was connected. It turned out water penetrated the sub enclosure, the amp inside the enclosure was shorting out, and the OSD folks were fantastic about sending me a replacement. I setup the replacement and thoroughly enjoyed listening to the setup for over 5 hours the day I installed the replacement. The next morning I heard the same crackling and popping, AGAIN! This time I broke open the sub enclosure to figure out what went wrong, and the OSD plastic logo on the very top of the sub enclose is not sealed with silicone like the rest of the sub enclosure is sealed up. My sprinkler system, or almost daily rain we get here in New Orleans penetrated that weakness (water will ALWAYS find a way), and the amplifier sits immediately under the nameplate inside the enclosure and got really wet. Amazingly, the OSD folks were REALLY kind enough to send me another replacement, but this time I shared with them the cause of the malfunction, and hopefully they will seal that part up if you order from them. I received the new OSD replacement setup, put lots of silicone on top of that OSD nameplate on top of the sub enclosure, and put that setup by my pool, and no problems yet!I shared all of this because that 2nd replacement OSD sub that I broke open I repurposed by clipping off the internal wires of the amplifier, satellite speaker outputs, etc. and converted the OSD sub into a passive sub now needing power from another source, and naturally sealed it up really good with lots of silicone. I searched long and hard for "outdoor" 2.1 or 4.1 amplifiers and this Fosi seemed to check all of the boxes, except that it wasn't waterproof. I wanted to put a quality amplifier in an outdoor weatherproof box to avoid the issues I had with the OSD sub setup. After getting it all hooked up, and tuning the amp (adjusting bass, treble, sub crossover to blend w/ the satellites, sub volume, and amp volume I leave in the same position sealed up in the weatherproof box to use my phone's volume when connected via Bluetooth), this Fosi 30D Pro amp sounds every bit as good, if not better, than my home theater setup with $1,000 Yamaha receiver, Paradigm speakers, and $2,000 SVS subwoofer. I actually go sit in my backyard now to listen to my garden speaker setup over my home theater setup it sounds so well balanced and that good. I play music (piano and trumpet), and definitely have an "ear" for music, and this Fosi amp is the real deal, especially when connected to the right kind of high quality speakers. One shortfall about the amp when sealed up in the weatherproof box is that the amp only has a manual lever switch on the unit itself to turn it on or off. Obviously it's not a good idea to leave the amp "on" at all times, and it's very inconvenient to open the weatherproof box every time you want to turn the amp on or off. My solution was to connect the power supply cord of the Fosi amp to an extension cord (bought an outdoor cable cover to protect that connection), and plugged the end of the extension cord into a short extension cord that has an outdoor "on/off" switch, which is then plugged into an outdoor electrical outlet box. Now, whenever I listen to the garden speakers with the Fosi amp, I just walk over to the easily accessible electrical outlet and flip the switch to "on," and my Bluetooth on my phone finds the Fosi amp in no time to connect, and I'm enjoying beautiful, full, rich music...easy peasy! And when I'm finished listening, I just walk over to the switch by the outdoor outlet and flip it to "off." This way the Fosi amp is only "on" when I'm actively listening to it. Hopefully that trick will give it plenty of life! I'll put a link for all of these things below.Here is the box I purchased to house the amp and power supply outdoors: https://www.amazon.com/gp/product/B0CP5RL1PZ/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1Here are the OSD Forza 4" satellite speakers I used for the system: https://www.amazon.com/OSD-Landscape-Mountable-Commercial-Resistant/dp/B0916DWXB5/ref=sr_1_2?crid=11056H4LSDN72&dib=eyJ2IjoiMSJ9.gXdDGu8oqU6XiOzDj8u_3rcA2hslL7UTIJmBiwG7-2hbrwNmy7k6LoCGQX15P6aautXVnUXHOW8BoAb_JmqIEb2bFIvZpUJ8T1ZWOvLHuwd3LDQPvNp6VHNJ-9AQlrunzEQWPpHtbrz0H-eBII_sl0FIgOVJnWu6vg6xTF7A6VKLvuDrKV8pffWRfNN1eoGQYeCVYvwJdTFHPFHNTHUf3gbmiawF4akuyNX8olshjtg.SEPJM2UZxVcC-f0JL_dDnT_TxCJ0EFLeuaDYJ76bdYQ&dib_tag=se&keywords=forza%2B4%2Bspeaker&qid=1719723606&sprefix=forza%2B4%2Bspeaker%2Caps%2C115&sr=8-2&th=1Here is the passive outdoor sub I would recommend to use with the Fosi amp: https://www.amazon.com/Forza-Outdoor-Weather-Resistant-Subwoofer/dp/B07R3FCV5K/ref=sr_1_1_sspa?crid=C9VIY16QR2TA&dib=eyJ2IjoiMSJ9.-gZpe9alIyquiwEciwwy_th2Z8h9E_FxalkH-E3bEjzcdF4a1gSljKYLatMM1MxJovLfQGnJmGzyVY0k8KcsB_K5VPKrbtmKJCDpPPnrGADUW_5iXfCiSmPhH0aB1nxnLJU696Gp7y4pfE5CufG9q8rjA26q7mi03W09ruL-tgn6bejQo1-Eg7ghcqR41wmPvbJFHa5iNOSbiDJ5ZKTOzgmqbhdywOyYWyDDSnvB70g.svHb9CJqXcq5JPseVJzdJpKNc1FxKVsuKGJGk9x6V0w&dib_tag=se&keywords=OSD+outdoor+subwoofer&qid=1719723686&sprefix=osd+outdoor+subwoofe%2Caps%2C131&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1Here is the outdoor "on/off" in-line switch on short extension cord: https://www.amazon.com/gp/product/B0BP7XL3MH/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&th=1Here is the OSD "all in one" active / powered 8" subwoofer with powered satellite outputs if you're interested (remember to put silicone sealer on top of the OSD nameplate to really seal it well): https://www.amazon.com/dp/B089DTP3MX?ref=emc_p_m_5_i_atc&th=1

I bought the Fosi amplifier because I have my NAD amplifier connected to two Cambridge Soundworks sub woofers but I wasn't getting much bass from the 8" woofer. I am very impressed by this amplifier, I can increase the volume of the woofers separately from the Yamaha two way speakers that are mounted in the same cabinet. I can now hear instruments on Jeff Beck's Blow by Blow LP that I've never heard before.