HDC4.0 Series (Discontinued)

(41 customer reviews)


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The Heavy Duty Competition 4’s are 4.0″ coil woofers boasting a power handling of 2000W RMS and peak power of 6000W.

The HDC is our high power handling class of subwoofers. These subs have proven themselves worthy of respect from competitors around the world. So when you decide it’s time to take your SPL to the next decibel our HDC subs are ready to assist.

HDC4.0 Series
RMS Power2000W
Peak Power6000W
Magnet Weight403oz
Coil Diameter4.0"
Coil Length54.356mm
Usable Throw69.85mm
Woofer Size12"15"18"
F(s)38.36 Hz
34.99 Hz28.26 Hz
Z(max)22.14 Ω21.48 Ω20.61 Ω
V(as)22.2 liters 64.22 liters 127.5 liters
L(e)1.831 mH1.192 mH1.904 mH
n(0)0.293 %0.572 %0.591 %
M(ms)308.7 grams331.8 grams517.8 grams
C(ms)0.056 mm/N0.062 mm/N0.061 mm/N
Sensitivity 1W/1m86.77db 1W/1m
89.68db 1W/1m
89.82db 1W/1m
SdComing SoonComing SoonComing Soon
Mounting Depth7.875"
Circle Cutout11.25"
Outer Diameter W/Gasket12.875"

Additional information

Weight N/A

12", 15", 18"

41 reviews for HDC4.0 Series (Discontinued)

  1. Steve Meade

    Wowser, that’s all I have to say about these. They slap better than I do in a fight with a two dollar hooker..fer realz yo!!! YOLO !!! GET THESE AND A ROCKFORD FOSGATE AMP and change your name to chicken hill

  2. Jovani Barrett

    I bought a 12″ and I’m currently breaking it in on a skar 2500 at 2 ohms. I can tell it wants more power. After next week, I’ll run it at 0.5 ohm and check how the sub sounds. I can’t wait to do so. I’ll recommend this sub to anyone who wants to do a single sub setup

  3. Cameron Straley

    Get one

  4. Grant

    This sub is insane. It genuinely THUNDERS. It was difficult to install and power, but after running 3500 RMS to it, I can tell it was worth it. I havent even begun to break it in yet and it already roars.

  5. Garrett Hinze

    It’s an amazing sub totally worth the money

  6. Todd Donnelly (verified owner)

    I do 155 + on music sealed dash score with 3 of these and 3 Soundqubed 3500.1s ,beast subs if used correctly

  7. Go Hard Or Go Home (verified owner)

    This is the biggest, baddest, most powerful subwoofer that I have ever had in my life. It hits the lows like I’ve never felt in my life. Currently breaking it in on 500 watts and its already too loud. Made a ported box for it myself. When I drive down the street with my windows down people turn their heads like wtf. Awesome sub. Good job to they guys at soundqubed.

  8. Monte’ T.

    This thing is a MONSTER!!! It is replacing my previous (2) 12 setup and it is MUCH LOUDER than the 12’s and of course a lot lower, all with pretty much the same power if not less. I currently have it in a 6.5 cuft(net) vented enclosure and its tearing my car apart! For power I have (2) Taramp HD8K’s(both wired down to 1ohm) and the HDC18 handles it well. During some SPL testing I clamped a little under 8000watts(both amps combined, after rise) and it handles it well. Im very happy with the purchase, and compared to the other big names out there I would pick Soundqubed again, hands down!

  9. Justin

    So far so good. Very stiff subs as I have only had them playing less than a week but I am truly impressed. I ordered 2 hdc4 18’s and they arrived within a week. Build so fresh, you could still smell the glue. That sat in the garage for 2 weeks beckoning out to me everytime I walked past. I had to reassure them there was a time and a place, there home was not finished being constructed. The long wait paid off and they are performing as expected. My current port is tuned at 46 hz with a port area of about 17 in2/ft3, leaving me about 12.2 ft3 net. I works wonders on anything above 40 and still does great down low. I haven’t reached down below 30 with this port but will see how they do when I get more ports built. Started out wired for 4 ohm and the 750 watts each they were seeing barely made them move. Wired down to 1 ohm, 1800 got them moving a lot better. The are breaking in nicely and sound better by the hour. Even with that power it was enough to bring home 1st place 3k-6k novice class and 2nd place street beat 2. You can’t go wrong with this sub!

  10. Kyle

    They certainly are great subwoofers and no doubt will take 2k rms without a problem, I have around 3800 running to 1 and it does reach thermal capacity in a song length or so, this is Korean 5k run at 1.6 ohms set with a smd dd-1 and a mechman 320 alternator, a few batteries never under 13.5 volts

  11. ron mcquade

    So I bought 2 HDC4 18,s put them in individual boxes of 6.5 cf tuned to 35hz ,powered by a MB Quart 3000-1, wired to 2 ohms for break in and I dont think I’m going to wire them to 1,because its louder than hell,zero muddy bass,extremely tight,monsterous sound. It redefines what bass is. If you want car alarms going off every where you go,people giving you room during rush hour traffic,having folks bitch at you for knocking stuff off their shelfs,,buy these subs. I’m a SQ for life fan after owning a set

  12. Benz

    I have a lil 3600 PPI pushing 2 18s lookin into better quality amp it def pushes and their loud as shit butt I nearly move em lookin at bigger PPI but I prob move to soundqubed amps I think sub’s are nasty though I just need bad ass amp

  13. Andres Chavez (verified owner)

    This sub is amazing. I sold two w7s to move onto this sub and it actually beats them in sound quality. sound qubed recommends setting your low pass filter to 100-125 hz and i have mine set to 100hz on a kicker zx 2500. I had a local guy build me box for the ford ranger ranger I have and wow. 6 cubic feet tuned at 37hz. huge port sub sits right behind me seat. This sub is hands down amazing. It gets into the high notes really well and just murders the lows on decaf music. A true head turner, people look at you like wtf?? I’m only feeding it 1500 rms right now 54.7VAC @50hz @ 2 ohms, not even calculating in box rise and its just a monster. After break in ill turn the gains up. Some guy pulled up next to me and asked me to put together a system for him, haha thats how you know you dont sound like dirty rattle and ugly noise. straight knock fell in love with this sub.

  14. michael cox (verified owner)

    We’ll first this the first 18″ sub I ever had and I was surely overwhelmed with the size and weigh of it sub is huge 71lb I had it about 4+ weeks now started out running it on hifonics brx2400 wired down to 2ohm for first week or so and just with that lil bit of power to start subs was still loud and deep then wired it to .5 ohm week later and started to realize the potential coming out of sub loud !!! Now currently have 2 brx2400s strap to one sub and wow sub went into beast mode right away and handling that power with ease really don’t think it’s enough but will definally get the job done for now so to wrap it up I been looking at these subs for a year or more and finally got one and not disappointed at all with it plan on doing 4 at first now am thinking 2 will be more than enough now 4 would just destroy what ever u put them in eventually great subs and for the price u can’t beat em

  15. Gavin

    My previous system consisted of 2 hifonics brx 2400s strapped on 2 sundown x 18’s in a 12.5 cube box tuned at 32hz. I recently upgraded to 2 Q3500s when they were on sale for $600 and 2 of these in a 12.5 cube box tuned at 37hz. Don’t let the high fs number on these fool you. Even with the much higher fs and higher tuned box these things get every bit as low as my x 18s did, sound better imo, walk all over them in terms of output and cost 20 bucks less per sub. You will not find a sub anywhere close to being on this level in this price range… It’s just not going to happen. If you are building a serious system and you want to get the most for your money then you gotta buy soundqubed. I guarantee you will not regret it. By far the best deal in car audio.

  16. Swiss

    I just put my hdc4 18 in the back seat of my 01 corolla last weekend in a 7 ft2 box tuned 2 32hz. Im runnin it on the q12200d at half ohm only puttin out about 1200 watts right now for the break in an it is so loud on the lows it feels like the car is going 2 fall apart! This thing hits down 2 the teens with authority, i cant wait 2 see what it can do on the full power of the amp after its broken in! These subs are amazing for the price and will not disappoint if your looking 2 get loud on a budget!

  17. steve lott

    ive had my hdc418 subs now for 2 weeks. They hit hard and deep man my whole vehicle is bowing out and flexin. I’m running them with the 3500d.1 amp. My box has about 18 cubic ft of air space. Cant wait till these subs are fully broke in its gonna be awhile cause they are super tight stiff. My poor Durango is taking a beating I hope the body doesn’t blow off the frame!!!lol

  18. brandon dove

    This sub flexs my blazer sooo hard. Has great low end response and only had it a week still scared to crank on it . Can’t wait for break in

  19. Dillon Austin

    Just bought the 18″ 4.0 today and the customer service was great. I called AQ and spoke to Greg. He placed my order fast and was very informative. I should receive my 18″ 4.0 in about a week. I have a 5000W 5000RMS Powerbass amp that will push it. Should only use about half this amp. Will be placing this monster in a Black 98 Dodge Ram 1500 Regular Cab SS/T Race Edition. Will be customizing my box to fill the space behind both seats as well as where the middle seat should be. Look forward to getting my sub, box built, and everything hooked up and tested. Will post another comment when set up is complete. Great service and will definitly buy some 8″s or 10″s 2.0s to go inside the truck aswell.

  20. Tyler

    This sub is an absolute beast. I have it in 4 cu tuned to 32hz and it slams like there’s no tomorrow. It’s power hungry and doesn’t even get warm in my setup (2154w). Would recommend to anybody. Great quality and sound.

  21. Zach

    I have this in a ported box tuned to 33hz and it is absolutely the best sounding sub I’ve ever heard it’s running about 2200 watts to the sub at one ohm and it handles it fine I would even push it higher just don’t have the amp for it but I would recommend to anyone

  22. Todd

    The Biggest and baddest made from Soundqubed and they sound beautiful and the motor force is awesome. love them

  23. jay

    Bought this sub a couple months ago, final had the time to install it and wwwoooowww way more than i expected. This thing is a monster! Soundqubed ftw!

  24. matt

    i bought 2 of these hdc415’s and all i can say is wow i only have 1600 watts rms going to them and everything in my jeep shakes. my windshield even moves in and out. cant wait to get the stetsom 10kd going and see what these will really do.

  25. melissa

    Awesome sub. Holds more than it should

  26. Mike

    I got two and I love them. Would tell anyone serious about getting loud to buy them.

  27. Hael Al-Aqeeli

    Hi There, Heard (2) of those in buddy’s vehicle, 12 cubes net B-Pillar Wall at 28hz, I am impressed with their OUTPUT, Could not hurt them even with distorted (5K amp) signal!!! YOU GET A LOT OF SUB I MEAN BEAST THAN WHAT YOU PAY enough said 🙂 Recommend them to anyone looking for destructive BASS, BTW do not get fooled with that high Fs, it is high due to its MASSIVE motor (Very High Motor Force), it produces the LOWS like no tomorrow 😉 Kindest Regards.

  28. Wayne Currie (verified owner)

    I have 2 of these in an 11.5 cube box after displacements running off of a Shok V (5k watts) tuned to 32. These things POUND!!! I’m absolutely in love. My windshield flexes so hard! The bass is clean too, it’s not a muddy sound at all. I highly recommend these subs!

  29. Tony brewer

    I bought this sub after upgrading from a hdc3 and holy hell is this thing worth the extra $100 I love this sub and it gets crazy low and loud and people shit themselves when I tell them I only have 1 15 if you are looking for a wow factor this is the sub for you

  30. Hudson Bell (verified owner)

    I bought one of these subs just one for my Infiniti G35s I’m running it on a 4,000 watt Boss Phantom amplifier which isn’t even a good amp and just that one sub made my rear view mirror fall off I’ve always went with cheaper subs but decided to spend the extra money after I blew my last one and if you spend that extra money on this one you will not regret it I am beyond pleased with this subwoofer! Outstanding piece, fast shipping, and great customer service amazing job soundqubed you’ll have my business for everything from now on! All I advice is you order some Qmat to go with it especially if it’s going in a trunk you’ll need it and Qmat as well is a great product and worth the money

  31. Sarah Zimmerman

    I am impressed with how much of a low end monster this is. I have it in 3.25 cubes after all displacments, tuned to 33hz with 75sq in. of port. It gets low and loud. Quality is amazing!

  32. Marybeth Knapp

    I recently removed 2 Rockford fosgate P3’s out of my car, and replaced them with 1 HDC4 15, and it BANGS way harder, and way cleaner, the best woofer ive ever heard in my life. Thanks Soundqubed

  33. Kue Kong

    Wow freaking amazing for 1 15″ sub-woofer. I have it in a sedan and all I got to say is King Kong in the trunk, seriously my trunk is trying to pop open. I’m running on stock electricals and from my calculation froma 110 amp alternator I’m only puting maybe a little over 700 rms. But dammmmmnnnnn it’s so damn loud my whole car is flexing like it’s about to break. Best sub ever owned. Soundqubed FTW.

  34. Josh Fedie

    awesome sub. worth every penny. i have it running in a 4.2 cube box tuned to 43 right now for burp but 3 for daily and it sounds great in my hatchback but it wants more power. i am running it at .5ohm daily at around 3krms and its laughing at it. so far with it not broke in im doing 148.5s in the kick dropping to 11.5 volts. after electrical upgrades to support new build i plan on changing tuning to a solid 38hz for daily/burp and running 2 2200.1s strapped

  35. Jason

    Only got the hdc4 12’s on a DD 1000 watts of power and these dig deep for the lows. I do have a 7k soundqubed amp to put on them when the rest of my electrical system gets in. So far I’m happy!

  36. Shawn

    Working on breaking them in still. They have a lot of power control very loud exactly what I expected. Thanks soundqubed!

  37. Josh knowles

    I have used thsee subs since they were audioque they are hands down dollar for dollar the best sub you can get. I have 2 HDC4 12’S and they are hitting harder than the two HDC3 15’S I went to competitions with. I’m thinking of getting 2 more or running one 18. The Customer service is great they have been in touch with me since the day I received them

  38. davy weil

    are these subs dual 1 ohms

  39. Maranda Brady (verified owner)

    I can do bags, pop cans and hair tricks. I got 2 of these on a Aq3500.1 and let me tell you, WOW. Best by far. Great job on the Hdc4s!!!

  40. Vincent Hunter (verified owner)

    I put one of these in my GMC siarra single cab. Took out my center consul and custom fit a 2.5 Cu ft. Box with a 3″ x 12.5″ slot port tuned to 29 HZ. I believe my truck is going to FALL APART!! I have over 140db for sure but my meeter only goes to 140 so im sure its higher than that. Probably close to 150. I am driving it with a SAZ 4500D and 3 batteries dual alts etc. the woofer takes the power!! The voice coil does not get stinky even after severe pounding bass sessions! I can over drive it here and there but im running more than double the rated rms power. Love it!

  41. Taylor Brown

    i just ordered it so i’ll post a real review when they get here and I listen to them.

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