**TL;DR**  
  
The Fat Frequency Deuce is very sub bass heavy iem that makes all the right compromises for it’s style of tuning.  
·   **Sound:** 6/10  
·   **Build quality:** 9/10  
·   **Comfort:** 10/10  
·   **Value:** 5/10 (retails for $300)  
  
**Context**  
This iem was kindly loaned to me by the goat u/mournfulmonk for review. I generally prefer iems that are non sibilant with with relaxed upper treble and upper mids and raised lower mids that add body to the sound (kinda the opposite of harman ie 2019).  
  
**Aesthetics & Build:** The iems are made fully made of resin, with a decent amount of weight, overall the shells feel very high quality, the faceplates have a solid lava (or graphite?) like design with a red hbb logo on left earpiece and fatfreq logo on right. I dig the aesthetics of this iem.  
  
**Fit, Comfort and Isolation:** These iems are what I would call medium-large, the shells are semi custom and the molding is excellent, I used these with L size roseselsa qt superbowl eartips and they fit my ears very snugly, in fact it’s one of the best fitting iems I have tried. Isolation on these is above average since the fit is so snug.  
  
**Cable & Accessories:** The cable is not great, its thick, kinky and microphonic but it has nice hardware that matches the iem’s aesthetics, the chin slider is tight and stays in place. While the cable is not ideal by any means I love the way it matches the iem, with it’s bright red colour. The cable comes in 3.5 mm and 4.4 mm options, I have the 4.4 mm. The 2 pin connectors have an unnecessary protrusion that does nothing but make the connection taller since these iems don’t have recessed connectors. The iems come with a set of tri clarion eartips but I have not used them along with an impedance adapter that add another 5ish db of bass shelf on top of an already ridiculous bass boost.  
  
**The Sound**  
The Fat Frequency deuce has a 2 dd configuration that follows the harman ie 2019 target curve with an absurd sub bass boost. These sound like a much refined version of truthear zero blues to me.  
  
**Bass (20 hz to 300 hz):** The whole point one would consider this iem is the bass shelf, these have an almost 8db subbass boost over harman ie 2019 which is already a subbassy target, If you’re a crazy person you can use the impedance adapter to add another 5db subbass boost.  
 This thing rumbles like you have a subwoofer strapped to the back of your head, its ridiculous and I love it, it doesn’t have nearly as much mid bass and the mid bass it has is just meh, so if you’re primarily looking for punch and tactility in your bass, this is not the iem for you.    
  
**Mids (300 hz to 6000 hz):** Since this iem follows the harman ie 2019 target curve, it has all the downsides that come with it, the midrange sounds thin and hollow due to scooped lower mids, it has a little too much upper midrange for my liking (a little too much 1-2k and substantial elevation from 3-5k) which makes vocals sound nasally to me. However, due to it’s absurd bass boost this iem kinda has to sound a little thin and shouty to not be muddy and low res, these along with the upper treble still gives it a lot of clarity and contrast for what is supposed to be a ridiculously bassy iem.   
  
**Mid Treble (6000hz to 10000hz):** I am not particularly picky about mid treble and the deuce does a fine job here, there are no sore peaks and it sounds reasonably smooth.  
  
**Upper Treble (10000hz to 20000hz):** Upper treble peaks are the bane of my existence and I hear a pretty nasty peak around 13k with short widebore eartips BUT as I said before, this iem needs air to still give it clarity through all that sub bass. So I understand why it is necessary, I do wish the air was more even and extended though.  
  
**Technicalities and Soundstage:** The fat freq deuce has tons of clarity for what it is (one of the few things harman ie 2019 excels at) The instruments are well separated and it always sound clean, It is an anti-mud basshead iem. Captures the sense of space in tracks adequately.  
  
**Comparisons**  
Compared to other iems with gigantic amounts of bass I’ve tried before:  
  
**OoopuX OP.22 (Bass dial on):** While the opus does a much better job with the treble and upper midrange (more filled in and thicker sounding) It sacrifices all the clarity in the process and ends up sounding muddy in most tracks, the op.22 bass mode also has much more mid bass.  
  
**Truthear Zero Blue 2 (impedance adapter):** Both of these use a 2 DD with a subwoofer crossover but the deuce is much more refined in it’s tuning, the upper mids on the deuce is not nearly as overwhelming and it never gets muddy like the blues. The deuce is also like 4x the price of these so it’s not really a fair comparison lol.  
  
**Conclusion**  
The deuce is supremely comfortable sub-basshead iem. Yes it is sibilant, shouty and airy but those feel like necessary evils to prevent it from being mud city. Overall I recommend these to anyone that wants ton and tons of subbass in their iems.  
   
 



Holy Fucking Basss