Instruction: First, identify the target attributes from the provided list. Then, scan the product title, description, feature, and brand to extract the values associated with each target attribute. Finally, create a list of dictionaries, each containing the extracted attribute, its corresponding value, and the source where it was found.

Input:
Product title: MB Quart Formula FKA157 5 x 7" 2-Way Coaxial Speaker System
Product description: 5 x 7" 2-Way Coaxial Speaker System with 50-100 Watt Power Rating and 40Hz-32kHz Frequency. Founded in the early 60's in Obrigheim, Germany, MB Quart is known worldwide for designing and manufacturing innovative and technically advanced audio products. From car, marine and home loudspeakers, MB Quart products exemplify "German Engineering." The Formula line of speakers is the perfect choice for the entry-level enthusiast who appreciates real sound quality and demands durability. MB Quart most recently revolutionized the mobile loudspeaker industry with WideSphere technology that emits extra-wide sound dispersion to listeners in order to enjoy the full range of music from almost any seating position in a vehicle. Audio and marine loudspeaker systems are put through stringent tests under the most extreme environmental conditions. Decades of refinement with meticulous attention to detail and tolerances in hand-built components have earned MB Quart a distinguished reputation for quality manufacturing, unmatched reliability and extraordinary performance. Praised by countless world-wide audio press awards and critical listeners around the world, MB Quart brings extraordinary engineering expertise, experience and design philosophy to a truly global Maxxsonics brand. Parent company, Maxxsonics USA, offers decades of combined experience and distinction with four brands MB QUART, Hifonics, Autotek and Crunch. We independently support and maintain these best-in-class brands to bring you some of the biggest, baddest and coolest products in the car, marine and home audio industry. Maxxsonics designers and engineers take great care and satisfaction in producing only the finest quality products to exceed your needs. Look for the stylized blue "M" on your product and packaging. It stands for quality, performance and power you can only get from Maxxsonics.
Product feature: 5 x 7" 2-Way Coaxial Speaker System with 50-100 Watt Power Rating and 40Hz-32kHz Frequency, Two-piece 0.75 (19mm) tweeter with titanium-coated dome, Rugged stamped metal chassis with a polypropylene cone for structural rigidity, Spider with woven tinsel leads for high power, Formula crossover with small chassis; Surface and flush mount tweeter enclosures
Product brand: MB Quart
Target attributes: Channels
Answer: attribute: channels
value: 2-way
source: product feature
attribute: channels
value: 2-way
source: product title
attribute: channels
value: 2-way
source: product description