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Discussion Starter · #1 ·
I've been slowly finalizing my design for my first DIY sub. This will be used almost exclusively for HT - any music listening will be background music type stuff.

Goals:

  • Footprint no more than 30w x 30d x 36h
  • Flat (or close to flat) response to 20hz with a smooth rolloff below that
  • < $500 for all components

Here's what I came up with:

  • Dayton TIT400C Titanic Mk III 15" driver
  • Either the O Audio 500w BASH plate amp or the PE BASH 500w plate amp
  • An enclosure with 8 ft^3 net volume tuned to 20 hz. It will be slot ported; my initial thought is to have the driver fire downward (I checked and the Titanic should have about 2% sag, so it should be OK) and the slot port will exit just under the top of the cabinet. Cabinet will be roughly 24d x 24w x 30-36h and will sit in the right rear corner of my living room.

I've attached the project files to this post. For reference, the charts read as follows:

  • Gray - Dayton Titanic, 8 cf, 500w, 20hz tune
  • Red - Dayton Titanic, 12 cf, 500w, 20hz tune
  • Blue - Dayton Titanic, 8 cf, 500w, 15hz tune
  • Orange - Dayton Titanic, 12 cf, 500w, 15hz tune
  • Yellow - Dayton RSS390HF, 8 cf, 300w (only way to limit excursion), 20 hz tune

Admittedly I am a n00b, but it seems to me that the best combination is the Titanic in an 8 cf box tuned to 20 hz, unless I can up the box size. It seems like this driver does not like a tune below 20 hz or thereabouts, unless I'm doing something wrong (definitely a possibility!)

I struggled a little balancing port size with resonance but think it came out OK. This will definitely need a highpass filter of some sort to manage excursion below 15-17 hz, depending on the enclosure size and tune. I wasn't sure how to model that (found the parameters for the Bash 300, but not the 500) so I left them all "natural". Because I had the numbers for the Bash 300, I added them to the RSS390.

Assuming I go with the 8 cf / 20 hz tune, my thought was to built it so that it fires downward and is slot ported, the slot to exit just under the "top" of the box. I found the calculations for sag on the PE forum, and if my math is right the Titanic checks in at about 2%, so it should be OK mounted horizontally. How much clearance would I need below the box? I could also set it up to use a side baffle if necessary, just would look cleaner pointed down.

Any recommendations and advice for firming these up would much appreciated!
 

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Admittedly I am a n00b, but it seems to me that the best combination is the Titanic in an 8 cf box tuned to 20 hz, unless I can up the box size. It seems like this driver does not like a tune below 20 hz or thereabouts, unless I'm doing something wrong (definitely a possibility!)

I struggled a little balancing port size with resonance but think it came out OK. This will definitely need a highpass filter of some sort to manage excursion below 15-17 hz, depending on the enclosure size and tune.

Assuming I go with the 8 cf / 20 hz tune, my thought was to built it so that it fires downward and is slot ported, the slot to exit just under the "top" of the box.
I think the 8cf box tuned to 20hz looks pretty good. Agree about the high-pass filter.

Are you sure you want to fire downward? There is no problem with doing so... Just curious.

I remember reading some discussions on sonosubs and clearance beneath the driver... I'd say a few inches - but I don't know of a good solid number. I have a down-firing HSU VTF-1 and for the 2 DIY subs that I've built I wanted the driver firing outward..
 

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For me personally I would go the Mach Audio 18 IXL if you can over any off the daytons.

Yellow: 12 cu ft mach audio 18 IXL tuned to 15hz with 500 watts
Grey: 12 cu ft Dayton titanic mk3 tuned to 18hz with 500 watts
Green: your plot for a 8 cu ft dayton titanic mk3 tuned to 20hz with 500 watts.

You can see the clear winner would be the mach audio and it only costs slightly more than the daytons. Like Mike says, it just depends on shipping.

Bare in mind the velocity on the mach audio is still pretty low and there isn't even a hpf applied due to being tuned to 15hz so you should not need one and you'll get alot more down low.

Please note none off your plots show the hpf engaged so you will loose x amount off spl when one is applied.

cheers

Graham
 

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Discussion Starter · #5 ·
I'd definitely be interested in pricing the Mach, but their website is down ATM. I'm also shopping for a new receiver (my old Onkyo TX-SV545 just isn't quite up to modern HT duties) so any money I save on the sub can go toward other components.

I don't generally listen at "hello officer" levels - one of the reasons I passed on doing a THT. That being said, my personal philosophy tends to toward "if some is good, more is better - and too much is just enough!"

Mike P - I was very unsure how to figure out how much bracing to put into the design so my volume numbers were more of a swag. Ideally, I'd like it to be 24x24x30-36 inches high. If I make it downward firing, it would need to be shorter to accomodate the "legs" under the box; if I point it out the side it can be the full 36" high. I have some room to play with the numbers as the location in the room is basically a dead corner. I had hoped to disguise it as a corner table and will be putting one of my surrounds and (likely) a lamp on it.

Is there a rule of thumb for bracing - every X inches, that sort of thing? I used the bracing and port calculators and took a swag at the volume of the amp as well, and in a 24x24x34 box I got 7.6 cf. Did I overestimate how much room the "stuff" will take up (bracing, driver, port, amp)?
 

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24x24x36 would be a bit over 8+ cu.ft. net volume. If it had 4" legs for a down firing sub then it would be about 7+ cu.ft. net volume. Bracing should be every 12" for a vibration free cabinet, but if the internal height were 30" then a brace at 15" would be fine. With a closer idea on your cabinet volume you can model the different subs to see what you like best.
 

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I would second (or third? ) the notion to go with a 15hz tune (or lower). You don't want to miss out on those lower frequency effects after you go through all the effort.

The Dayton ref HF 15 will tune low and puts out plenty for me in a 7 cu. ft. Box.

I like Dayton but now I think there are better drivers for your money from Mach, AE, or FiCar.
 

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Discussion Starter · #9 ·
Resurrecting one of my first threads, as - after much wrangling - my first DIY sub is complete. Build thread here.

Learned much along the way, and the next one will be even better :)

Thanks to all who assisted, whether you knew it or not!
 

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I've been slowly finalizing my design for my first DIY sub. This will be used almost exclusively for HT - any music listening will be background music type stuff.

Goals:

  • Footprint no more than 30w x 30d x 36h
  • Flat (or close to flat) response to 20hz with a smooth rolloff below that
  • < $500 for all components

Here's what I came up with:

  • Dayton TIT400C Titanic Mk III 15" driver
  • Either the O Audio 500w BASH plate amp or the PE BASH 500w plate amp
  • An enclosure with 8 ft^3 net volume tuned to 20 hz. It will be slot ported; my initial thought is to have the driver fire downward (I checked and the Titanic should have about 2% sag, so it should be OK) and the slot port will exit just under the top of the cabinet. Cabinet will be roughly 24d x 24w x 30-36h and will sit in the right rear corner of my living room.

I've attached the project files to this post. For reference, the charts read as follows:

  • Gray - Dayton Titanic, 8 cf, 500w, 20hz tune
  • Red - Dayton Titanic, 12 cf, 500w, 20hz tune
  • Blue - Dayton Titanic, 8 cf, 500w, 15hz tune
  • Orange - Dayton Titanic, 12 cf, 500w, 15hz tune
  • Yellow - Dayton RSS390HF, 8 cf, 300w (only way to limit excursion), 20 hz tune

Admittedly I am a n00b, but it seems to me that the best combination is the Titanic in an 8 cf box tuned to 20 hz, unless I can up the box size. It seems like this driver does not like a tune below 20 hz or thereabouts, unless I'm doing something wrong (definitely a possibility!)

I struggled a little balancing port size with resonance but think it came out OK. This will definitely need a highpass filter of some sort to manage excursion below 15-17 hz, depending on the enclosure size and tune. I wasn't sure how to model that (found the parameters for the Bash 300, but not the 500) so I left them all "natural". Because I had the numbers for the Bash 300, I added them to the RSS390.

Assuming I go with the 8 cf / 20 hz tune, my thought was to built it so that it fires downward and is slot ported, the slot to exit just under the "top" of the box. I found the calculations for sag on the PE forum, and if my math is right the Titanic checks in at about 2%, so it should be OK mounted horizontally. How much clearance would I need below the box? I could also set it up to use a side baffle if necessary, just would look cleaner pointed down.

Any recommendations and advice for firming these up would much appreciated!
I completely and completely agree with you about the high-pass filter, I support it. And the 8cf 20hz box is amazing. And I have been doing sound for a long time, recording songs for performers. I also work part-time as a designer, create covers for songs, for this I use a cool creator Color names and hex codes . Here I am such a multifunctional sounder :)
 
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