Hello, I am a complete beginner in speaker and amplifier schematics. I want to build a 6-inch down-firing subwoofer as a replacement for my old and worn-out 2.1 speaker subwoofer. For the L/R channels, I am using 4-ohm 2.75-inch 15-watt Harman Kardon full-range speakers and 1.5-inch 3-watt tweeters for treble.
Here are the parameters I am using and the design for the subwoofer:
-Box size: 25x25x25 cm made from 15mm MDF (30mm board at bottom for stronger driver mounting)
-Amplifier: ZK-TB21 TPA3116D2 Class D (32-pin original)
-Subwoofer driver: 6-inch Legacy LG 696-2 (parameters are attached)
-Ventilation port: 5 cm diameter with a 16 cm long port
There are a few questions I would like to ask, and I hope you can help me determine the answers:
1. How much power supply wattage do I need for this setup? Is using 19V 2.37A = 45 watts enough?
I have this adapter from an old Asus laptop charger with a DC port.
2. With these subwoofer specifications, is running at 2 Ohms better than 4 Ohms?
3. Is my box design suitable for achieving a soft and deep bass character? I will place the subwoofer under my computer desk.
4. My subwoofer box design is inspired by the Audioengine S8, but dimension-wise, I followed the Audioengine S6, which has a 6-inch driver and similar box dimensions around 25 cm. Is this good get smooth and deeper bass profile?
Good explanation really help me figuring this issue, thank you.
Here are the parameters I am using and the design for the subwoofer:
-Box size: 25x25x25 cm made from 15mm MDF (30mm board at bottom for stronger driver mounting)
-Amplifier: ZK-TB21 TPA3116D2 Class D (32-pin original)
-Subwoofer driver: 6-inch Legacy LG 696-2 (parameters are attached)
-Ventilation port: 5 cm diameter with a 16 cm long port
There are a few questions I would like to ask, and I hope you can help me determine the answers:
1. How much power supply wattage do I need for this setup? Is using 19V 2.37A = 45 watts enough?
I have this adapter from an old Asus laptop charger with a DC port.
2. With these subwoofer specifications, is running at 2 Ohms better than 4 Ohms?
3. Is my box design suitable for achieving a soft and deep bass character? I will place the subwoofer under my computer desk.
4. My subwoofer box design is inspired by the Audioengine S8, but dimension-wise, I followed the Audioengine S6, which has a 6-inch driver and similar box dimensions around 25 cm. Is this good get smooth and deeper bass profile?
Good explanation really help me figuring this issue, thank you.
Attachments
If this is a subwoofer that you're going to use as part of a multimedia system for your computer, then 45 watts should be more than enough, unless that subwoofer driver is really inefficient.
Do not run that driver at 4 ohms. The paper suggests that to get 4 ohms you should connect only one voice coil of that dual-voice-coil driver. Don't do that. It's a DVC driver that's 4 ohms per coil, so design for either 2 ohm or 8 ohm use.
As for the box, use a box design program like WinISD to see how the driver will perform in the box that you're planning to use.
Do not run that driver at 4 ohms. The paper suggests that to get 4 ohms you should connect only one voice coil of that dual-voice-coil driver. Don't do that. It's a DVC driver that's 4 ohms per coil, so design for either 2 ohm or 8 ohm use.
As for the box, use a box design program like WinISD to see how the driver will perform in the box that you're planning to use.
The smaller woofer you propose to use has an Fs = 48Hz, Qts = 0.86, and Vas = 14 litres. Its Thiele–Small parameters seem to make it unsuitable for use in a small vented box such as the one you are thinking of using.