Many of you here will be familiar with the concept of "buttkickers" as a subwoofer alternative/supplement. These use haptic transducers instead of typical drivers to transmit low frequencies to the user, and are typically mounted in chairs or couches. While some theaters and home theaters use these, they are still relatively niche. Regal's "RPX" theaters use them, but I rarely bother spending the extra ticket cost over the standard experience. There is a subniche of this market dedicated to all in one "vest" solutions, primarily marketed for mixing and mastering, and use in gaming, Subpac is the most recognized and respected, bHaptic markets almost exclusively to gamers, and Woojer is somewhere in between. While these can technically be used with speakers, they are effectively an all in one dac/amp/subwoofer replacement for use with headphones.
Woojer's VEST 4 was 250 dollars at costco this black friday, so I decided to spring for it, and I've had it for about 2 weeks. There's a cheaper "STRAP" that has only one haptic transducer to the Vest's 6, but since it's only half the price, I wouldn't consider it.
When it arrives, it MUST be fully charged for ~3 hours using the included 20volt usb c charger and requires a firmware update using a phone. It must be a phone or tablet, Apple or Android, there is no PC software. The app lets you adjust the profile, which is just EQ/DSP. Based on my testing, there is no reason to not use the "low latency" preset. This disables all DSP and uses the full 0hz-~250hz frequency response of the vest. The DSP profiles just make it more vibratey than impactul.
As I said, this is effectively all in one dac/amp/subwoofer, and it has some compromises as a result. If you connect the Vest by bluetooth or USB-C to your source device, it's technically a DAC. I have no clue how good the dac is, but I'm sure its fine. You can also connect the vest by analog 3.5mm stereo jack to the source device. I'm not sure what voltage its technically supposed to recieve, but Woojer says to "set the source device volume to maximum," so presumably its capable of handling anything a 3.5mm jack would reasonably be capable of sending. It works just fine plugged into my Qudelix 5k with the 2VRMS setting and max gain.
There are 3 ways of daisy chaining headphones to the Vest. First, yo could technically just use a y splitter and power your headphones off the same cable that supplies the vest, but YMMV. The other way is to plug your headphones into the 3.5mm jack on the vest, which is what I do with my ATH M50X and FT1 Pro. Woojer's site claims the 3.5mm jack can supply up to 138mw into 16 ohms headphones, and lists no other figures for power. I have no clue what means for higher impedances, but its loud enough for my headphones. Unfortunately, it has an audible hiss at the highest gain setting. The hiss is inaudible in most music, games, and films. Going down 2 clicks completely removes audibilty even when silent for me.
The single largest fail is when you try to daisy chain bluetooth headphones. It might just be my unit, and I am emailing support about it, but there is audible "distortion" when you connect bluetooth headphones to the vest. The transients sound clipped. The bass is okay, but drums are unbearable. Initially, this was very disappointing, because I planned to use my Qudelix 5k for headphone EQ. I had the idea to instead use it the other way, with the Qudelix as a DAC/Preamp and just plug the headphones into the vest. I was initially concerned about the headphone EQ affecting the vest's frequency response this way, but A/B testing bass filters didn't show much difference. While it can go up to 250hz, it seems immune to even large filters above ~120hz, which is where the harman bass shelf starts. And if you just need a low shelf filter, there's no peaks or dips to affect the vest. I found this ironic despite the marketing about the built in DSP. Another diffculty is is finding the correct ratio of rumble to headphone sound at the ear. Between the EQ and hiss, I never use a rumble setting above the lowest. If you don't use EQ, you might want a higher rumble setting.
Now, we can finally get to the sound. The effect is almost TOO accurate and TOO impactful. You feel EVERYTHING in the subbass, even if you can't hear it through the headphones. In some songs, there's just an ambiguous rumble that doesn't seem to be coming from any instrument. On the other hand, something even spookier about the Vest is how high its frequency response can go. This will depend on how a song or youtube video is mixed and mastered, but if you take your headphones and put your ear to one of the transducers, its crazy how much you can hear. Deep male voices are often intelligible. If the bass line is melodic, you can often follow the melody. This means the Vest is more subjective than I thought it was. It can feel unnatural to actually feel everything that exists in the subbass for music or movies. By far, the worst experience I had with the Vest was in an Ocean documentary. It felt extremely unnatural to feel the vibrations from recordings underwater, since when you swim underwater normally, the deafening deep sounds from the water moving over your ears isn't felt as vibrations in your chest.
Finally, fit for me was an issue. I am very skinny and even at the tightest, all 6 transducers are not flush with my skin. I remedied that by wearing thick winter clothes inside (our furnace is broken right now anyways.) I find clothes between the vest improved the effect even for the transducers that were flush before. If you're sized like a more regular American, it should be fine.
Overall, I can recommend Woojer's Vest 4 if its what you're looking for. If you can snag it from Costco before Cyber Monday ends, its the cheapest option of the lot. The previous Vest 3 was closer to 500 dollars, Subpac is a 1000 dollar preorder, and most feedback I saw on reddit for bHaptic is that its ill suited for music.
