Ascendo ASC-21SPPS The21 SUB Ascendo 21" PRO - Passive Sealed Subwoofer
SKU: 21346670400

Ascendo ASC-21SPPS The21 SUB Ascendo 21" PRO - Passive Sealed Subwoofer

$8955.00 $9950.00
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Ships within 48 hours · Estimated delivery Jul 8 - Jul 13

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Description

Ascendo ASC-21SPPS The21 SUB Ascendo 21" PRO - Passive Sealed SubwooferTHE 21 SUB PRO PASSIVE SEALED PASSIVE SEALED The21 SUB PRO PASSIVE SEALED is a jewel in the pool of subwoofers designed for the highly educated customer that is on the quest for the highest performance and understands how to differentiate sound quality. When this customer experiences the The21 SUB PRO PS unparalleled output and uncolored sound, the measured test results we publish translate perfectly to realized performance. ASCENDOs policy is to be

THE 21 SUB PRO-PASSIVE SEALED

  • PASSIVE
  • SEALED

The21 SUB PRO PASSIVE SEALED is a jewel in the pool of subwoofers designed for the highly educated customer that is on the quest for the highest performance and understands how to differentiate sound quality. When this customer experiences the The21 SUB PRO PS unparalleled output and uncolored sound, the measured test results we publish translate perfectly to realized performance. ASCENDO’s policy is to be completely transparent and publish measurements done by independently certified third-party labs to provide factual data, thereby enabling informed, educated decisions. The The21 SUB PRO subwoofer is so far above and beyond the competition in every aspect; refined musicality, tightness, and output levels suitable for a 21"" driver. It is also engineered to operate perfectly in sync (in phase) with our Infrasonic subwoofers; The24 PRO, The32 PRO, The50 PRO, The80 PRO when there is a desire to reproduce movie content below 20Hz with the same authority, precision, and musicality.

Compared to conventional subwoofer motor concepts, the ultra-modern double-gap motor of this custom-made 21" driver with two outer and two inner voice-coils enables more linear travel and much faster directional changes with higher sound power and significantly lower power compression.

Specifications

Speaker type

21-inch forward-firing, dual gap motor structure with 2 inner and 2 outer voice coiles, neodymium motor.

Xmax

18 mm excursion each direction (36 mm linear), voice coil remaining in homogeneous magnetic field, linear and lowest distortion

Passive | Active

Passive

Recommended amplifiers 

1Ch DSP + Amplifier are required. Min. recommended amplifier: 109 Vrms, 154 Vpk, 27,3 A; equivalent to 3000W@4Ω with correct RMS & Peak limiting & compression settings.

Recommended ASCENDO amplifiers  

(With additional external 1CH DSP: AIA2-6004), DSP4-10K2  

Principle 

Sealed 

SPL (peak / half space 2 pi)

Measurement data
139 dB @ 63 Hz peak 

Frequency range

Measurement data
55 Hz - 500 Hz / -3 dB
28 Hz - 500 Hz / -15 dB

Efficiency 

97 dB  / 1W/m

Power handling 

 4000 W

Impedance 

4 Ω 

Air volume displacement 

2,88 L / in comparison 21" standard cinema subwoofer 1,76 L

Directivity horizontal x vertical in Deg°

360°

Input Terminal

Neutrik

Enclosure

Internally braced birch ply and MDF

Width 

23,62 " | 600 mm

Hight

43,31 " | 1100 mm

Hight with feet 

44,29 " | 1125 mm

Depth without grille

14,57 " | 370 mm

Depth with plug

14,57 " | 370 mm

Weight

112,44 lbs | 51kg

Finish 

Structural paint black

Custom colour options 

Piano lacquer, colour of choice, matt or other finishes upon request

Shape customisation 

Upon request 

Mounting 

Floor standing with feet

 

The21 SUB PRO ACTIVE SEALED is supplied with a front cover as standard

Technical modifications subject to change without further notice

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 21346670400

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4.7 ★★★★★
Based on 508 reviews
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Product Reviews
C
Verified Purchase
CHAOS
Alexandria, US
★★★★★ 5
Make sure you get this brand. The look alikes are trash!
Very durable and fun! My Pitbull chews on this constantly and loves to have treats or peanut butter, put in the bottom of it as an extra treat. A friend of mine bought a similar looking toy that was destroyed by her pitbull in moments. This one is better quality and has stood the test of this power chewer. The rubber is very thick and he chews it constantly but it stays in tact. It is soft enough to squeak if he gets a hold of it just right, but that’s the rare treat. The size is perfect for my 80 pound boy. I am also able to throw these toys in his pool for him to dive for them. Definitely in great value for the price.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 19, 2026
B
Verified Purchase
Bryan de Jesús
Los Angeles, US
★★★★★ 4
Indestructible, but maybe too much?
Color: Orange, Size: Medium
Not too enticing for my dog, but, it is definitely indestructible! He chews on it every so often, but less than I had expected. I think the material is so rock hard that it offers little incentive for him to chew on it.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 27, 2026
J
Verified Purchase
Jessica OMalley
Phoenix, US
★★★★★ 5
Best I've Tried
Color: Blue Shark, Size: Medium
With my pitty pup, there's no such thing as an indestructible toy, but this has been the most impressive so far. It's lasted days vs the typical minutes his new toys survive. It has a squeaker, but no fluff, and this has been great. He's been trying to get at if for a long time with no success! He has tore thru the rubber portion, but there's still plenty of play left in this toy. The 3 different textures keep him interested vs the hard material toys he rejects or chews on them too long and I worry about tooth wear. Definitely buying more.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 7, 2026
L
Verified Purchase
Lgiff
Houston, US
★★★★★ 5
This has been a challenge for my extreme chewer! The toy is winning
Color: Green
Indestructible? Not for my pitbull. Except on this toy. She has slowly chewed some of the outer portion on the backside, but it still has a lot of gnawing time left. This is her go-to toy now. she carries it nearly everywhere. She loves it. I am amazed at how well it is holding up. Within minutes, hours or a few days, the other "indestructible" toys I've purchased, never survived as described. This is a heavy toy! Not for the weak! I cannot stress enough the extreme chewer my dog is. Yet, I can see this toy lasting months. It won't be pretty then but it will most likely still be a favorite chew toy. I'm glad I found this and will be buying more. FYI's... 1) Chewability-5 stars 2) Softness-1 star, it's solid but chewable, 3) Bounce-0 stars, No bounce, it's heavy!, Playability- 5 stars. My dog plays with it, lets it lay with her when resting. Nearly always within her reach. She sleeps with it! That's love.
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Reviewed in the United States on January 2, 2026
M
Verified Purchase
Michele Johnson
Bozeman, US
★★★★★ 5
My buddy has been chewing on this for an hour!
Color: Green, Color: Green
This dog toy has been a great addition to our dog’s toy collection! My dog can be a pretty aggressive chewer, so I’m always looking for toys that are durable and can actually hold up to daily play. This one has been surprisingly tough and has lasted much longer than many other toys we’ve tried. The material feels strong and well made, and the design makes it easy for my dog to grip and chew. He loves carrying it around and tossing it during playtime. It’s also great for keeping him busy and helping reduce boredom, especially when he has extra energy to burn. Another thing I like is the texture of the toy. It seems to help keep my dog engaged, and it’s sturdy enough that I don’t worry about it falling apart right away like some softer toys do. It’s been used for chewing, tugging, and even some fetch around the house, and it’s still holding up really well. The only small drawback is that I wish it had a squeaker inside. My dog absolutely loves squeaky toys, and I think that would make it even more exciting and keep him interested for longer periods of time. Overall though, this is a very solid and durable dog toy that’s perfect for dogs that love to chew. If you’re looking for something tough that can help keep your dog entertained and reduce boredom, this is definitely worth try
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Reviewed in the United States on March 12, 2026

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