Introduction: These set of speakers were built originally to meet one of my customer’s requirement. There were some rough concepts in my mind, which I materialized into these medium size Bookshelf speakers.
Project Objective: To make a medium size passive bookshelf speakers as per customer needs. Following criteria was discussed and finalized:-
- The drivers chosen are 4″ Mid-Bass shielded Robertson Audio.
- The cabinet should be 0.118Ft3 ~ 3.3Liters.
- It should have good fit and finish within reasonable budget.
- There should be appropriate passive crossover to get the best audio experience from given drivers.
- It should run well with LM1875 DIY KIT that the customer has previously bought from me.
Project Cost: This Project will cost you approximately Rs.4650 + 3 Weekends (Please refer to “Project Cost” and “Pricing” section on “Terms and Condition” section on sidebar for complete information)
- 3/4th of 4′ x 2′ , 0.5″ MDF or particle board sheet (I have used Action TESSA Marine 12mm MDF board).
- Cutting jigs for making circular holes for front panel (Please refer to “My Tools” section).
- Round-over router bit for smooth finish.
- 4 x push steel terminal connectors.
- 2 x 4″ Robertson Audio 12Ohm Mid-Bass Drivers.
- 2 x 1″ Polycarbonate dome tweeter. I have used 1″ cut circular shaped (pls refer to project pics) 6 Ohm Sharp Malaysia tweeter because they sound excellent and have matching front panel to go with Robertson Audio Mid-Bass.
- 0.4uH Inductor for LPF filter for Mid-Bass drivers (passive crossover).
- 2.7uF/250VAC polyester capacitor for tweeters (passive crossover).
- Basic woodworking tools to cut boards, drill and joinery.
- 6~8 sheets of 1000Grit/400Grit/100Grit sandpapers for Orbital/Sheet Sander.
- PVC pipe as port tubes (I used 50mm PVC pipe since the drivers were matched better with 50mm in 3.3Liter enclosure).
- Setup for spray-paint/primer (you can use brush/roller if you don’t have spray-paint setup).
- Stick on silicon feet. (Or you can use general purpose plastic feet).
Here are some pics of finished project:-