Fosi Audio HT4S Multi-Channel Power Amplifier for Simracing
In the audio world, Fosi Audio is a well-known name, but in the sim racing community, they’re still relatively unknown. That’s not too surprising. Fosi Audio, based in China and founded in 2017, specializes in audio equipment. The company is best known for producing high-quality yet affordable audio amplifiers, DACs (Digital-to-Analog Converters), and other related audio accessories. The brand focuses on delivering products that are accessible to both audiophiles and general consumers, emphasizing compact designs that offer excellent sound quality without breaking the bank.
However, with the HT4S multichannel power amplifier, Fosi Audio has developed a device that’s also appealing to sim racers, as it allows you to power bass shakers for extra immersion at a relatively low cost. When Fosi Audio reached out to us for a review, we didn’t hesitate to say yes. We love elements that make our virtual races even more immersive, and we’re very curious to see what the Fosi Audio HT4S has to offer in that regard.
The Fosi Audio HT4S multichannel power amplifier is available for around $145.00 USD (approximately €120.00), excluding shipping costs, via Fosi Audio’s online store. In addition, you’ll need one or more bass shakers and the appropriate speaker cables. In our case, we also needed an optical cable since we wanted to connect the amplifier digitally alongside our current Logitech Z623 (2.1) speaker system.
Packaging and Contents
The package was originally shipped from China and ultimately delivered via PostNL. We received a box surrounded by foam and sealed in plastic. The shipment took four business days to arrive, and no import fees were charged upon delivery.
Upon unboxing, we found a black box featuring a silhouette of the Fosi Audio HT4S amplifier. Unfortunately, all the corners of the box were dented due to the way it was packed. This is something we’ve seen before with shipments from China. A sturdier outer box would have been better. Fortunately, the contents remained undamaged.
Upon opening the box, we find a thick white foam insert with two cutouts. In one cutout is the amplifier, wrapped in an anti-static sleeve. The other cutout contains the remote control, a power cable, a 3.5mm jack plug cable, and a Bluetooth antenna. In short, the packaging includes all the basic essentials needed for this amplifier.
Fosi Audio HT4S
The Fosi Audio HT4S is a versatile amplifier capable of powering both (outdoor) speakers and bass shakers, with support for Bluetooth streaming. This compact unit is an All-in-One Mini Amplifier, integrating both a DAC (Digital-to-Analog Converter) and a powerful amplifier. It supports stereo sound and can drive up to 5 channels, allowing for easy switching between 4.1 and 5.0 channels. Additionally, it offers various input options, including Bluetooth, AUX, and optical digital inputs, along with pre-out capability and support for up to 5 speakers and/or bass shakers.
We understand that not every sim racer is an audiophile, but we still want to share the specifications of the Fosi Audio HT4S amplifier. The amplifier has a signal-to-noise ratio (SNR) of ≥88dB and a total harmonic distortion (THD) of ≤ 0.03%, ensuring a clear and powerful signal. The terminal impedance ranges from 4-8Ω, with a nominal power of 30W per channel for the four main channels and 60W for the fifth channel. The maximum power output is 50W per channel at 4Ω. The device operates on an AC voltage of 110V – 240V and has compact dimensions of 6.1 x 7.2 x 2 inches (about 15.5 x 18.3 x 5.1 cm), making it suitable for a variety of use cases.
Installation and Configuration
We placed the Fosi Audio HT4S amplifier on top of our computer, a perfect spot where it’s out of the way but still easily accessible. We mounted our Dayton Audio BST-1 bass shaker directly under our seat on an aluminum profile using a special mounting kit. The setup process was fairly straightforward. We started by connecting the bass shaker to the amplifier with a 1.5 mm² speaker cable. Next, we connected the amplifier to our computer using an optical cable. After that, we plugged in the power cord, and the device was ready to use. Finally, we inserted two AAA batteries into the remote control, allowing us to easily control the amplifier from our seat.
In SimHub, we select the correct audio output under the ‘ShakeIt Bass Shakers’ menu, which in our case is the digital (SPDIF) output of the sound card. We then set the channel to ‘Mono’ since we’re only using one bass shaker for now. After clicking ‘Test Now,’ we immediately feel feedback in our seat, confirming that everything is working. Next, we choose various effects like gear shifts, road impact, road rumble, road vibration, and traction loss. Initially, we set each effect to 100%, then adjust them as needed if any effect feels too intense. Everything works, everything is set up, and we’re ready to hit the track!
The Use
Driving with a Bass Shaker under our seat is a new experience for us, and as soon as we start a race in Assetto Corsa Competizione, we’re instantly thrilled. The extra dimension added by the vibrations brings a deeper immersion into sim racing, which we find to be a valuable enhancement. These effects simulate various driving experiences by delivering physical sensations like gear shifts, kerb impacts, bumps, and road vibrations. The Fosi Audio HT4S amplifier performs exceptionally well, providing ample power to deliver these effects clearly and powerfully. The device barely gets warm, indicating that it handles the bass shaker effortlessly, even during extended sessions.
Although the amplifier drives the Bass Shaker without any noticeable delay, we did find that some effects, like road rumble and road vibration, were initially a bit too intense. We adjusted these effects to a more comfortable level, ultimately settling on around 80%, which provided the perfect balance between immersion and comfort.
The controls on the amplifier respond smoothly, making it easy to fine-tune various tones. The large volume knob is satisfying to use and features a striking orange color, giving the device a fresh look. The remote control is also of good quality and responds very accurately to our input. On the bottom of the amplifier, there’s a small switch that lets you toggle between sub and flat modes. In flat mode, the CEN/SUB channel outputs a full range, while in sub mode, it only emits low-frequency signals from 20 to 300 Hz. We noticed little difference between the two modes and opted for sub mode since the vibrations from a bass shaker are primarily composed of low-frequency signals.
While Fosi Audio targets a broad market with the HT4S amplifier, it would have been convenient if there was a complete package available, including one or more bass shakers and the necessary cables. This would have made the installation process much simpler. As it stands, we had to order everything separately, which required a bit of research.
Overall, we’re very enthusiastic about the experience and plan to add four more bass shakers in the form of Dayton Audio TT25 PUCK tactile transducers. Fortunately, the Fosi Audio HT4S amplifier can power up to five bass shakers in total, so we won’t need any additional equipment. These ‘pucks’ can be mounted at each corner of our sim rig, allowing us to simulate various road effects for each wheel, enhancing the immersion even further.
Conclusion
We can confidently say that the Fosi Audio HT4S amplifier, combined with a Bass Shaker, is an excellent addition to our sim racing experience. The installation of the HT4S with the Dayton Audio BST-1 bass shaker was quite straightforward, and using it has been trouble-free. The device does exactly what it’s supposed to do: it provides enough power and precision to deliver various effects, such as gear shifts and road rumble, realistically and without noticeable delay.
Operating the amplifier, both via the buttons and the remote control, is smooth and intuitive. While the option to switch between sub and flat modes offers additional flexibility, we noticed little difference between the two modes in practice. We ultimately chose the sub mode, as the vibrations from a bass shaker primarily consist of low-frequency signals, and this seemed to be the best setting for our needs.
We’re looking forward to expanding the system with additional bass shakers, knowing that the HT4S amplifier has enough power and capacity to drive them all efficiently. We believe this expansion will create an even richer and more immersive sim racing experience!
Are you as excited as we are and looking for a good amplifier to drive one or more bass shakers? The Fosi Audio HT4S multichannel power amplifier is available for around $145.00 USD (approximately €120.00), excluding shipping costs, from Fosi Audio’s online store.
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