Just a thread to post about some home audio / theatre upgrades I'll be doing. Lots of DIY stuff similar to the car audio thread. Will be a very slow burn. As I'll only be working on it when I feel like it.
Over the last couple week I've been working on a subwoofer cabinet for a 'new' living room speaker. First up design. Going w/ a sealed cabinet. Normally the larger the cabinet the more efficient the speaker is. But the downside is speaker has more pressure, which can cause over excursion, which is the speaker traveling more than it is mechanically save to do). The problem w/ box building is there are so many variables. And TBH I think I probably screwed up here. I should have added multiple variations of the box in the same graph so I could compare. Will keep this in mind for next time.
This is the SPL aka efficiency of the same subwoofer but with 2 different cabinet sizes. One a very small 1c.ft. The other a monstrously large 3.5c.ft. About 4dB louder w/ the same amount of power @ 20Hz. That is a huge difference. So I went and started building the 3.5 cubic foot box. I'll show my mistake at the end.
Not going to show all the pics of building a box as it isn't very exciting. All the wood was reused from old projects. Made from 1/2 mdf most of it. Then for the piece the sub mounted was doubled up 3/4" MDF. Feet are 3d printed. PLA w/ TPU as a cushion layer on the bottom. Sub is a 12" Pioneer that I bought off FB for $25.
The little box on the floor is the amp I'll be powering it with. 150W RMS, which ain't a whole lot. Obviously not staying in the middle of the floor.
Compared in size vs the old Velodyne sub I was using before.
Cross over on the receiver is @ 40Hz. And it sounds really nice, clean and deep. Remembered how I said that larger boxes cause over excursion? Well the way you combat this is by using a subsonic filter, which adds a crossover below 20Hz to help reduce really low frequencies to prevent the sub from blowing it self apart. The box building tool does a simulated graph of excursion.
See how everything from about 37Hz and below is above the red line for the first one? That sub is going to blow, fast. The other is the small box.
So I apply a 17Hz 48dB/octave (every octave will drop 48dB in power) @ 17Hz. Crossovers do affect frequencies above the crossover point as well tho. You can see the excursion is now in the safe area.
Over the last couple week I've been working on a subwoofer cabinet for a 'new' living room speaker. First up design. Going w/ a sealed cabinet. Normally the larger the cabinet the more efficient the speaker is. But the downside is speaker has more pressure, which can cause over excursion, which is the speaker traveling more than it is mechanically save to do). The problem w/ box building is there are so many variables. And TBH I think I probably screwed up here. I should have added multiple variations of the box in the same graph so I could compare. Will keep this in mind for next time.
This is the SPL aka efficiency of the same subwoofer but with 2 different cabinet sizes. One a very small 1c.ft. The other a monstrously large 3.5c.ft. About 4dB louder w/ the same amount of power @ 20Hz. That is a huge difference. So I went and started building the 3.5 cubic foot box. I'll show my mistake at the end.
Not going to show all the pics of building a box as it isn't very exciting. All the wood was reused from old projects. Made from 1/2 mdf most of it. Then for the piece the sub mounted was doubled up 3/4" MDF. Feet are 3d printed. PLA w/ TPU as a cushion layer on the bottom. Sub is a 12" Pioneer that I bought off FB for $25.
The little box on the floor is the amp I'll be powering it with. 150W RMS, which ain't a whole lot. Obviously not staying in the middle of the floor.
Compared in size vs the old Velodyne sub I was using before.
Cross over on the receiver is @ 40Hz. And it sounds really nice, clean and deep. Remembered how I said that larger boxes cause over excursion? Well the way you combat this is by using a subsonic filter, which adds a crossover below 20Hz to help reduce really low frequencies to prevent the sub from blowing it self apart. The box building tool does a simulated graph of excursion.
See how everything from about 37Hz and below is above the red line for the first one? That sub is going to blow, fast. The other is the small box.
So I apply a 17Hz 48dB/octave (every octave will drop 48dB in power) @ 17Hz. Crossovers do affect frequencies above the crossover point as well tho. You can see the excursion is now in the safe area.
