Newbie with a plan. Just need fine tuning. - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 10 Old 08-29-2012, 06:13 AM - Thread Starter
Newbie
 
sprinklerman's Avatar
 
Join Date: Aug 2012
Posts: 5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Hello all. 1st of all ,thanks for all the info so far. Ive lurked here quite a bit to research my A/V receiver ( Denon 991) and my surrounds.

Now its time to address my sub setup.
Ive pretty much decided to try a SIMPLE ported 15" for my 1st DIY build.

Im leaning toward the Dayton HF 15" in a ported,low tuned , enclosure. (Thinking about 18hz)
I have approx 25"w X 16"h X 65"L max to work with. The enclosure will need be either up-firing or down- firing because of the limited height available.
My room is approx 14x 21 with 2 door openings.

A few questions:
1. Can this sub be mounted up or down firing? Or only front? ( was reading about woofer sag???)
2. if i keep the enclosure about 12" that should give me 4" of woofer clearance..is that sufficient?
3. Ive downloaded WinISD but dont understand how to CORRECTLY model. Can someone point me in the right direction with regards to properly powering the dayton 15 HF, as well as proper sizing or enclosure and ports?
4. Id prefer to do round ports for my 1st try, would PVC or Precision Ports be easier? Noticed they dont come in the length i THINK i need.

If any other info is needed , id be happy to provide it, Thanks in advance!
sprinklerman is offline  
Sponsored Links
Advertisement
 
post #2 of 10 Old 08-29-2012, 09:13 AM
Advanced Member
 
mtg90's Avatar
 
Join Date: Aug 2011
Location: Millbrook, IL
Posts: 754
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 118
Hello spriklerman,

1: The sub should be able to be mounted up or down firing with much problem.

2: 4" driver clearance should be sufficient but I would go no less.

3: shoot for around 8 cuft internal which is doable in your space. 10"h (half inch for woofer frame + 3/4" material both sides) x 23.5"d x 63.5" internal comes out to be ~8.6 cuft, subtract woofer/port/bracing and you should be right about 8 cuft. If you want to use a plate amp any of the 500 watt models at PE (Yung without boost/Bash/Dayton) should be a good match, they should all have a built in subsonic filter which will keep excursion under control below tuning.

4: Two 4" ports 23" long should get tuning where it needs to be (18hz) and be able to keep velocity in an acceptable range. You could use either PVC or the Dayton 4" port kits, however while PVC cost far less it does requires a little extra work to mount and you don't get the nice flares.

Should make for a nice capable first time sub build.
mtg90 is offline  
post #3 of 10 Old 08-29-2012, 11:58 AM - Thread Starter
Newbie
 
sprinklerman's Avatar
 
Join Date: Aug 2012
Posts: 5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Thank you for your input.

I did a little looking today ,and found a Car Audio shop that would build me an 8cuft enclosure with a slot port tuned to 18hz,for 200.00. Im kind of looking forward to doing it myself,but after materials,i dont know if i CAN build it any cheaper than that. Of course i'm assuming that they would do it correctly,whereas if I do it,i know i'll take my time and do it right.

As far as the actual shape of the enclosure,i remeasured and i'm leaning toward making it around 13" tall ,so i can make it a touch shorter. 13x24x48" (approx 8.66 cuft)
1. How does that model as far as the 4" PVC for a port vs a slotted port?
2. Also,if i go down firing,is there a benefit (or loss) by adding a "platform" for the sub to fire towards vs firing into the carpet?

Thanks for your input!
sprinklerman is offline  
post #4 of 10 Old 08-29-2012, 02:55 PM
Advanced Member
 
mtg90's Avatar
 
Join Date: Aug 2011
Location: Millbrook, IL
Posts: 754
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 118
I don't think down firing into the carpet vs platform should make much difference as long as you keep the 4" clearance. As long as the slot port cross section is equal to or greater then two 4" PVC ports it will work fine and model the same.

Just remember the spec'd enclosure volume is internal, you need to subtract for wall thickness, your enclosure will be 6.96 cuft internal and that is before driver/bracing/port displacement as well. It would still work in that enclosure size, f3 is just moved up by 2 Hz and port length would need to be + 6" (for two 4" round ports).
mtg90 is offline  
post #5 of 10 Old 08-29-2012, 04:08 PM - Thread Starter
Newbie
 
sprinklerman's Avatar
 
Join Date: Aug 2012
Posts: 5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Ahh. I see. I can make it longer,no problem. Nows not the time to be space stingy.

Are there any programs that are known to accurately compute the port volumes of the round ports? Im still not 100% sold on having the audio shop biuld the enclosure,because he felt 18hz was too low of a tune. When i told him in doing research on several HT forums, that it was fairly common,he gave me some nonsense reply.

1. Also ive been reading about subsonic filters that are on certain plate amps not being compatible with lower tuned enclosures. How do i know which one to get? Ive looked at the Bash on PE,and the Oaudio.
sprinklerman is offline  
post #6 of 10 Old 08-29-2012, 09:32 PM
Advanced Member
 
mtg90's Avatar
 
Join Date: Aug 2011
Location: Millbrook, IL
Posts: 754
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 118
What do you mean when you say to compute port volumes of round ports? If you are looking for the volume displaced in the enclosure by a round port that would be (Pi*r^2) * port length.

The Bash, Dayon and Yung all have a subsonic filter in there around 18-20hz which will work good with your tuning, the Oaudio looks to have a selectable subsonic filter but should still be set to 20hz. I think what you might be reading applies to very low tunes in the mid to low teens and under where a 20hz filter would kill off all that.

Car audio and home theater are really two entierly different animals.
mtg90 is offline  
post #7 of 10 Old 08-29-2012, 10:42 PM
Member
 
JohnnyWash1's Avatar
 
Join Date: Feb 2009
Location: Seattle, WA
Posts: 134
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 11
If space is at all a concern, I would STRONGLY recommend the HO version. WIth a ported design, you will still get more SPL and extension than you can use.
JohnnyWash1 is offline  
post #8 of 10 Old 08-30-2012, 04:34 AM - Thread Starter
Newbie
 
sprinklerman's Avatar
 
Join Date: Aug 2012
Posts: 5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by mtg90 View Post

What do you mean when you say to compute port volumes of round ports? If you are looking for the volume displaced in the enclosure by a round port that would be (Pi*r^2) * port length.
The Bash, Dayon and Yung all have a subsonic filter in there around 18-20hz which will work good with your tuning, the Oaudio looks to have a selectable subsonic filter but should still be set to 20hz. I think what you might be reading applies to very low tunes in the mid to low teens and under where a 20hz filter would kill off all that.
Car audio and home theater are really two entierly different animals.

Yes the volume that the ports will displace. That is the formula i was using,but it was from memory,so i wasnt sure of it accuracy. Thanks

Im not too concerned with space,i just want it make the wisest use of the space i have available.

Q: Ive noticed that running a larger (10 cuft vs 8) seems too extend the lows a little better. am i doing it right as far as "real world" testing would show?

Q: when i run WinISD, what amount of wattage do i model with?
sprinklerman is offline  
post #9 of 10 Old 08-30-2012, 11:03 AM
Advanced Member
 
mtg90's Avatar
 
Join Date: Aug 2011
Location: Millbrook, IL
Posts: 754
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Liked: 118
Going with a 10 cuft does give a little more extension but I don't know if it would be noticable, you only see about a 1.5 dB increase between 17 and 21hz if you think the 2 extra cubic feet are worth that then by all means build it at 10cuft.

Use whatever wattage in WinISD that is equal to the amp you be using, if 300watts use 300, if 500 watts use 500. smile.gif

You will see that if you plug 500 watts in cone excursion does exceed 14mm, it get close to 16mm in the 8cuft but it should still be in the safe zone.
mtg90 is offline  
post #10 of 10 Old 08-30-2012, 04:12 PM - Thread Starter
Newbie
 
sprinklerman's Avatar
 
Join Date: Aug 2012
Posts: 5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Thanks again. That all makes it clearer. Im leaning toward the 500 watt just in case i want to add more subs later. I can always turn the gain down for now i guess.
sprinklerman is offline  
Reply DIY Speakers and Subs

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off