Sounds good, I am sold, is there another driver that you prefer to the dayton near the pricepoint?
And do I need high pass / low pass filters? I dont see them in the build you posted above below is the part list from that thread. Going to start ordering stuff tomorrow. I need to mail order everything to my buddy to bring via plane to me down here (besides the mdf), so lmk if there are some non obvious small things to make my life easier.
Driver 249.75
Binding post plate 10.90
Binding post 18.47
1" MDF 5 sheets required for a pair. You would probably need 3 sheets for a single without rearranging the cut layout. 64.00/sheet
Wood glue 20.00
PL 20.00
epoxy 5.00
socket cap screws 6.00
threaded inserts 8.00
paint 18.00
bondo 8.00
MDF screws 12.00
Rockboard 60 or 80 30.00
At the price of that driver, I don't know a better one. In any case a different driver would require a complete redesign. The T/S parameters of that driver are just perfect for an optimal sounding ported box.
You won't need Eq, and I don't think the driver needs a subsonic filter. There is little content below 20 Hz.
Everyone thinks wrongly there is a lot of sonic energy below 60 Hz, when in fact when you look at the spectrum meter there is in fact very little. The myth arises because most bass reproducers are very inefficient and take gobs of power to produce little energy. Since you will not be feeding much power to this unit to produce prodigious bass, then the issue of driver damage below F3 is non existent as far as I'm concerned. The tuning frequency is not the cut off point. The cone excursion is well controlled by the alignment until 15 Hz where there is still very useful output, in fact this is the 6 db point and you don't want to cut that off with a filter.
I did not address the issue of down firing. This is fine as long as you are using larger main speakers, that can be crossed over at least as low as 60 Hz. If you do make the woofer down firing, I would not make the port down firing. There will be a lot of air flow in and out of the port and most of the bass output is from the port and not the driver. From 15 to 20 Hz almost all of the output is from the port. I'm pretty sure the air gap under the speaker would change the dynamics of the port significantly and muck the speaker up.
Crossovers are not brick wall and sub crossover attenuate at 24 db per octave, so even if you cross at 60 Hz, there is needed and useful output to 120 Hz. If you cross at 80 Hz then useful and needed output to 180 Hz.
The actual real demands for power are between 100 Hz and 2.5 KHz. With huge demands from 150 Hz to 1500 Hz. The acoustic power demands below 100 Hz are tiny in fact, compared to the band I mention. That is why a sub barely offloads a receiver at all. However that myth gets perpetuated on this forum all the time.
You do not need to buy a 1000 watt amp for this sub. 100 to 200 watts will be more than enough.
For questions about construction details and advice, I would PM Haoleb.
