10” 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK

10_600W_Car_Subwoofer_Active_Underseat_Bass_Box_Audio_Sub_Speaker_Amplifier_UK_01_ma
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK

10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK
Tip : Any issue about item, feel free to contact our customer service firstly in message, we will offer you best solution until you are satisfied. Max Output Power: 600w / RMS: 90W. High level Input Sensitivity: 0.9v. Low Level Input Sensitivity: 300mV. Low Pass Filter: 50-150Hz. Fully functional and easy to debug. 68 mm Slim fuselage, installed under the seat. Design of high temperature resistant coil. Fine workmanship and good performance. 1 x Active Subwoofer. 1 x Power Cord. 1 x Grounding OFC Wire. 1 x Audio Line. 1 x Control Line. 1 x Subwoofer High Level Input Line. 1 x Installation Package. 1 x User Manual. We check all items before sending out. All products are brand new, never been used or refurbished. Most packets arrive in 5 days. If there is any delay, it may be caused by bad weather, busy season and some other reasons. We are not responsible for wrong or undeliverable address. We are only responsible for once re-sending expense for replacement due to defects. We have always been doing our best to provide the best service and reliable products for every customer. We will reply your emails and questions within 24 hours.
10'' 600W Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier UK

Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT

Car_Subwoofer_Active_Underseat_Bass_Box_Audio_Sub_Speaker_Amplifier_12V_600W_BT_01_don
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT

Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT
You may also like. For Suzuki V-STORM650/DL650 17-19 Windscreen Adjusters Windshield Mount Bracket#. For Nissan GT-R R35 2.2M/86.6Car Side Skirts Extension Rocker Panel Splitter BT. 2PCS FOR LAND ROVER DISCOVERY 2 WHEEL BEARING HUB WITH SENSOR FRONT #TAY100060. For Seat Ibiza MK5 5dr 6F Standard FR 18-24 Front Bumper Lip Spoiler Splitter BT. Carbon Fiber Look Door Handle Cover Trim Molding Trim For Honda Civic 2022 2023. 2m Red-Line Side Skirt Extension Rocker Splitter Lip For Jaguar XE XF XJ XKR BT#. Universal Motorcycle Motorbike LED Rear Tail Brake Stop Light Fender Red Lamp BT. For Peugeot 305 306 405 406 407 Lockable Roof Rack Cross Bars Luggage Carrier BT. 2.2M For Seat Ibiza Leon Toledo Side Skirt Extension Rocker Panel Gloss Black UK. Carbon 138cm For Vauxhall Insignia Saloon Rear Trunk Lip Spoiler Boot Wing Lip B. For 3Series E46 E90 E91 E93 F30 F31 Side Skirt+Rear Lip+Front Bumper Lip Spoiler. We promise to help you solve it as soon as possible, so that you are absolutely satisfied. Does not include local weekends and holidays! Max Output Power: 600w / RMS: 90W. High level Input Sensitivity: 0.9v. Low Level Input Sensitivity: 300mV. Low Pass Filter: 50-150Hz. Fully functional and easy to debug. 68 mm Slim fuselage, installed under the seat. Design of high temperature resistant coil. Fine workmanship and good performance. 1 x Active Subwoofer. 1 x Power Cord. 1 x Grounding OFC Wire. 1 x Audio Line. 1 x Control Line. 1 x Subwoofer High Level Input Line. 1 x Installation Package. 1 x User Manual. We are a company specializing in motorcycle parts accessories, Car accessories, Industry accessories, Home Garden accessories, we provide high-quality products at affordable prices and excellent service. But, we’d like to assist you to receive the goods smoothly if there are anything we can do here. Please check it whether it far to you. PA20-33, PA35-38, PA49, PH30-39, PH49, PH50, FK20; PA62-72, PA74-75, PA80, PH40-41; PA34, PA41-48, PH42-44; PA60-61, PA73, PA76-78; BT; IV1 – 3, IV12, IV30, IV36, KW14; IV4 -11, IV13 – 28, IV31-32, IV40, IV52-54, IV63, KW1-13, PH20-26, AB36-38, AB44 – 45, AB54-56 ; HS1-9, IV41-49, IV51, IV55-56; IM1-9, IM99; PO30-41; KA27-28; KW15-17; PH17-19, FK 18-19; ZE1-3; TR21-25. Out 30-day Satisfaction Guarantee assures our customers that they will receive all orders promptly and exactly as described. Used items will not be accepted for return. 8mm For Renault For Citroen Silver Square Oil Sump Drain Plug Key Tool Remover. #SCART To HDMI Cable Video Adapter SCART To HDMI Converter SCART To HDMI Adapter. 180201556 Fit For AUDI A1 A3 A4 A5 A6 A7 A8 Q3-Q7 Fuel Gas Tank Cap Band Cord BT. A221470065 Fuel Tank Cover Cap Cord Rope Strap Fit For Benz W211 W212 W203 W204. Carbon Fiber Rear Fender Mudguard Motorcycle Accessory For Sur Ron Light Bee X. For Seat Ibiza Arona Leon Black +Red Car Lower Front Bumper Lip Spoiler Splitter. Replacement Remote Controller for Bose Wave Music System AWR1-B1 AWRC-C1 C2 C3. 2m Red-Line Side Skirt Extension Rocker Splitter For Benz A-Class W176 W177 BT. For John Deere 1023E 1025R 2025R Compact Tractor 120 Loader Zerk Grease Caps BT.
Car Subwoofer Active Underseat Bass Box Audio Sub Speaker Amplifier 12V 600W BT

600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST

600W_Active_Underseat_Car_Bass_Box_Audio_Subwoofer_Sub_Speaker_Amplifier_UK_FAST_01_nlb
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST

600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST
Please contract us firstly If there are any problems when you received the package. Max Output Power: 600w / RMS: 90W. High level Input Sensitivity: 0.9v. Low Level Input Sensitivity: 300mV. Low Pass Filter: 50-150Hz. Fully functional and easy to debug. 68 mm Slim fuselage, installed under the seat. Design of high temperature resistant coil. Fine workmanship and good performance. 1 x Active Subwoofer. 1 x Power Cord. 1 x Grounding OFC Wire. 1 x Audio Line. 1 x Control Line. 1 x Subwoofer High Level Input Line. 1 x Installation Package. 1 x User Manual. We check all items before sending out. All products are brand new, never been used or refurbished. Most packets arrive in 5 days. If there is any delay, it may be caused by bad weather, busy season and some other reasons. We are not responsible for wrong or undeliverable address. We are only responsible for once re-sending expense for replacement due to defects. Good communication is helpful for both of us to resolve any problems and issues. We have always been doing our best to provide the best service and reliable products for every customer. We will reply your emails and questions within 24 hours. We are a company specializing in motorcycle racing parts accessories, Industry accessories, Home Garden accessories, we provide high-quality products at affordable prices and excellent service.
600W Active Underseat Car Bass Box Audio Subwoofer Sub Speaker Amplifier UK FAST

Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light

Slim_Underseat_Powered_Car_Subwoofer_10in_800W_With_LED_Atmosphere_Light_01_jmpm
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light

Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light
Slim Design with Powerful Performance: The under subwoofer is a 10in slim active car truck subwoofer with a built in amplifier, housed in a rugged aluminum alloy casing for outstanding heat dissipation and reliable performance. Enhanced Sound Experience: Featuring a spider speaker protector and speaker LED ambient light ring design, this car subwoofer adds a touch of style with blue LED lights that illuminate upon vehicle start up, giving your car a cool appearance. Convenient Wired Remote Control: The car subwoofer comes with a wired bass volume remote controller, offering gain, bass boost, and crossover controls to deliver a stunning bass experience with a peak power of 800W. Versatile and Safety Functions: The subwoofer supports low level input and is compatible with high level input, adjustable input sensitivity, along with thermal, short circuit, and overload guard circuits. Impressive Performance: The subwoofer boasts a frequency response of 20Hz – 150Hz, phase switch of 0° or 180°, low pass filter of 50Hz-150Hz, bass boost of 0 to +12dB, total harmonic distortion (THD) of. 90dB, high level input sensitivity of 0.9V, and low level input sensitivity of 300mV. Item Type: 10 Inch Subwoofer. Material: Aluminium alloy Speaker Size: 10in Peak Power: 800W Impedance: 2.6? Low Pass Filter: 50Hz-150Hz Bass Boost: 0 to +12dB Frequency Response: 20Hz-150Hz Signal to Noise Ratio: >90dB THD Total Harmonic Distortion. 1 x 10 Inch Ultra Thin Active Subwoofer 1 x Controller 1 x Copper Cable 1 x Copper Wire 1 x Copper Ground Wire 1 x Manual 20 x Installation Accessories. Please refer to the user manual for operating instructions. We will reply your message within 48 hours. If you do not receive our reply within 48 hours, pls. Post a message again because sometimes our message system may block some emails. If you are satisfied with our service, pls. Our aim is to provide Level Customer Service, your recognition will encourage us greatly and serve you better. We strive to keep all our customers satisfy. We will do our up most to exceed your expectations in customer service, communication and dispatching of your orders.
Slim Underseat Powered Car Subwoofer 10in 800W With LED Atmosphere Light

Match 8 Upgrade Underseat subwoofers for BMW 5 G30 G31 G38 Series 400w Pair Set

Match_8_Upgrade_Underseat_subwoofers_for_BMW_5_G30_G31_G38_Series_400w_Pair_Set_01_njzf
Match 8 Upgrade Underseat subwoofers for BMW 5 G30 G31 G38 Series 400w Pair Set
Match 8 Upgrade Underseat subwoofers for BMW 5 G30 G31 G38 Series 400w Pair Set
Match 8 Upgrade Underseat subwoofers for BMW 5 G30 G31 G38 Series 400w Pair Set

Match 8 Upgrade Underseat subwoofers for BMW 5 G30 G31 G38 Series 400w Pair Set
Match MW 8BMW-D Sub 8 Direct Fit Underseat Subwoofer Pair. 2 x Subwoofer MATCH MW 8BMW-D. 2 x Plug & Play connectors for original BMW cable harness. 1 x Instruction manual. The MW 8BMW-D subwoofers are not only the ideal upgrade for those who are dissatisfied with the bass response in their BMW, but particularly for those who want to realize unprecedented space saving installation concepts. The BMW-specific baskets and Plug & Play connectors allow a fast and easy installation into the original mounting positions of all BMW model ranges with under-seat subwoofers. Designed to fit all E/F series cars including 1 series, 2 series, 3 series, 5 series, 6 series, 7 series plus the “X” ranges. Nevertheless, these subwoofers are also perfectly qualified for universal applications. Furthermore, the special speaker connector with its gold-plated screw terminals allows two different configurations and therefore flexible connection options. With the ex works installed connection bracket the subwoofer has an impedance of 1 x 4 Ohms, otherwise each voice coil can be driven individually (impedance 2 x 2 Ohms) and allows perfect combination with MATCH Plug & Play amplifiers. No matter if these subwoofers are used as bass upgrade in your BMW or as problem-solver in small sub enclosures, they will definitely add loads of powerful bass for musical enjoyment. 8 / 200 mm subwoofers with very low mounting depth for shallow subwoofer designs and under-seat installation in BMW vehicles. Allows to use extremely compact, sealed enclosures. 2 x 2 Ohms impedance per woofer for most flexible connection options. Fit directly into the original mounting positions under the front seats of all BMW model ranges with under-seat subwoofers. Also well suited for universal use in shallow subwoofer designs. The special speaker connector with its gold-plated screw terminals allows two different configurations and therefore flexible connection options. Power RMS / max. 200 / 400 Watts. 2 x 2? Resonance frequency Fs 46 Hz. Mechanical Q factor Qms 4.45. Electrical Q factor Qes. Total Q factor Qts. Equivalent air volume Vas 7.3 L. Efficiency 1 W / 1 m SPL 90 dB. Mechanical resistance Rms 0.74 kg/s. Voice coil diameter ø. Linear excursion Xmax +/- 4.0 mm. 239 mm / 9.41. 175 mm / 6.89. 40 mm / 1.57. We offer a collection service on some of our items. Please call our retail shop before collecting an item. WE DO NOT REPLY TO ANY DIRECT EMAILS. Whatever you are looking for, we have a great range of vehicle products for your car, van or motorhome. We are confident that you will find everything you need and more at Motor Solutions. Motor Solutions are proud suppliers of a wide range of products from some of the top vehicle security, multimedia and accessories manufacturers including Clifford car alarms, Smartrack vehicle trackers, Cobra motorhome security devices, and Snooper Ventura sat nav systems for motorhomes. Thanks For visiting Motor Solutions.
Match 8 Upgrade Underseat subwoofers for BMW 5 G30 G31 G38 Series 400w Pair Set

VIBE OPTISOUNDBMW82-V3 BMW 8 Underseat Subwoofer 2 Ohm

VIBE_OPTISOUNDBMW82_V3_BMW_8_Underseat_Subwoofer_2_Ohm_01_fsdq
VIBE OPTISOUNDBMW82-V3 BMW 8 Underseat Subwoofer 2 Ohm

VIBE OPTISOUNDBMW82-V3 BMW 8 Underseat Subwoofer 2 Ohm
All our OEM speaker upgrades come with the brackets and wiring connectors for direct Plug & Play installation. By Using high efficiency drivers and Neodymium motors we are able to keep the speakers lightweight and easy to install. Now available in both 2 Ohms and 4 Ohms models giving the ability to upgrade the BASE system as well as the BMW HIFI and HK using the 2? Variant which is more suited to the factory amplifier. Speaker Size: 8? (200mm). Peak Power: 345 watts. RMS Power: 115 watts.
VIBE OPTISOUNDBMW82-V3 BMW 8 Underseat Subwoofer 2 Ohm

Match MW 8BMW-D Sub 8 Direct Fit Underseat Subwoofer Pair for BMW 5 Series E60

Match_MW_8BMW_D_Sub_8_Direct_Fit_Underseat_Subwoofer_Pair_for_BMW_5_Series_E60_01_hwhf
Match MW 8BMW-D Sub 8 Direct Fit Underseat Subwoofer Pair for BMW 5 Series E60
Match MW 8BMW-D Sub 8 Direct Fit Underseat Subwoofer Pair for BMW 5 Series E60

Match MW 8BMW-D Sub 8 Direct Fit Underseat Subwoofer Pair for BMW 5 Series E60
Match MW 8BMW-D Sub 8 Direct Fit Underseat Subwoofer Pair for BMW 5 Series E60. 2 x Subwoofer MATCH MW 8BMW-D. 2 x Plug & Play connectors for original BMW cable harness. 1 x Instruction manual. The MW 8BMW-D subwoofers are not only the ideal upgrade for those who are dissatisfied with the bass response in their BMW, but particularly for those who want to realize unprecedented space saving installation concepts. The BMW-specific baskets and Plug & Play connectors allow a fast and easy installation into the original mounting positions of all BMW model ranges with under-seat subwoofers. Nevertheless, these subwoofers are also perfectly qualified for universal applications. Furthermore, the special speaker connector with its gold-plated screw terminals allows two different configurations and therefore flexible connection options. With the ex works installed connection bracket the subwoofer has an impedance of 1 x 4 Ohms, otherwise each voice coil can be driven individually (impedance 2 x 2 Ohms) and allows perfect combination with MATCH Plug & Play amplifiers. No matter if these subwoofers are used as bass upgrade in your BMW or as problem-solver in small sub enclosures, they will definitely add loads of powerful bass for musical enjoyment. 8 / 200 mm subwoofers with very low mounting depth for shallow subwoofer designs and under-seat installation in BMW vehicles. Allows to use extremely compact, sealed enclosures. 2 x 2 Ohms impedance per woofer for most flexible connection options. Fit directly into the original mounting positions under the front seats of all BMW model ranges with under-seat subwoofers. Also well suited for universal use in shallow subwoofer designs. The special speaker connector with its gold-plated screw terminals allows two different configurations and therefore flexible connection options. Power RMS / max. 200 / 400 Watts. 2 x 2? Resonance frequency Fs 46 Hz. Mechanical Q factor Qms 4.45. Electrical Q factor Qes. Total Q factor Qts. Equivalent air volume Vas 7.3 L. Efficiency 1 W / 1 m SPL 90 dB. Mechanical resistance Rms 0.74 kg/s. Voice coil diameter ø. Linear excursion Xmax +/- 4.0 mm. 239 mm / 9.41. 175 mm / 6.89. 40 mm / 1.57.
Match MW 8BMW-D Sub 8 Direct Fit Underseat Subwoofer Pair for BMW 5 Series E60

6X9 inch ported built in Amplifierd speaker box 600w Extreme Bass box underseat

6X9_inch_ported_built_in_Amplifierd_speaker_box_600w_Extreme_Bass_box_underseat_01_dqa
6X9 inch ported built in Amplifierd speaker box 600w Extreme Bass box underseat
6X9 inch ported built in Amplifierd speaker box 600w Extreme Bass box underseat

6X9 inch ported built in Amplifierd speaker box 600w Extreme Bass box underseat
This is the Brand New MA Audio Compact Subwoofer with Built-in Class A/B Amplifier and is designed to be installed in various small, tight spaces, with the ability to fit under seats, behind seats or inside small storage compartments this product is extremely versatile. Don’t let the size fool you as this product is capable of producing great bass from a tiny space. 6×9 inch Low profile Amplified Car Subwoofer. 6″x9″ woofer with Built-in Amplifier. Variable Low Pass Filter, Subsonic Filter and Bass Boost. Mesh Protection Grille for woofer. Remote Subwoofer Level Control. Thermal, Overload and Short Protection Circuits. High Level and RCA Low Level Inputs, Switchable Phase Control. Green & Red LED power status indicator. 29 x 21.5 x 6.5 cm.
6X9 inch ported built in Amplifierd speaker box 600w Extreme Bass box underseat