Ported how low is too low? - Page 2 - Home Theater Forum and Systems - HomeTheaterShack.com

Reply
 
Thread Tools
post #11 of 40 Old 12-14-14, 02:24 PM Thread Starter
Senior Shackster
John
 
Join Date: Feb 2012
Location: Michigan
Posts: 324
My System
Send a message via Skype™ to phazewolf
Re: Ported how low is too low?

I have and can't decide. I don't really care about size I am more likely going to be at 30cf tube that if my wife complains can be used to hide inside from her. The output is what I am thinking about and I do know there is content below even 15HZ it's just how much can I get too with a reasonable amount of drivers and avoid my wife filing paperwork to leave at the same time.

I know 2 will be fine and the cost is not too great overall at 3M distance it will give me 115db output at 12HZ and above and that is without any room gain. My current setup at 12HZ is around 90db so if get a pair of the Ftw I should be very happy.
phazewolf is offline  
Sponsored Links
Advertisement
 
post #12 of 40 Old 12-14-14, 04:58 PM
Senior Shackster
Steeve B.
 
Join Date: Dec 2010
Location: Saguenay, Quebec, Canada
Posts: 248
Re: Ported how low is too low?

LLT Explained

The main advantage to tune lower than 20hz it to have the group delay of the port as low as possible and usually in the zone where you don't hear the sound but rather feel it only. Tuning to 12hz will indeed allow you to have the great output of ported subwoofer, you will also be able to go almost as low as best sealed subwoofer and you will have the same sound quality (often qualified by thight sounding bass). Tuning to 20hz would yield a little more output but you would also start hearing the added group delay of the port. Essentially the main advantage of LLT is not to hit 12hz because anyway there is rarely any content down there and anyway most of the bass that is felt is 40-60hz range. The advantage of tuning to 12hz is the added SQ while still gaining the extra output of the port. The disadvantage here would be the size. LLT are huge like horn subwoofer.

I would tune to 12hz like you planned and add an HPF just to be safe and don't have to bother with bottoming the subwoofer unless you have a really large room, then you might have to sacrifice some SQ and tune higher to get the extra output.
Steeve-O is offline  
post #13 of 40 Old 12-14-14, 10:09 PM Thread Starter
Senior Shackster
John
 
Join Date: Feb 2012
Location: Michigan
Posts: 324
My System
Send a message via Skype™ to phazewolf
That was kind of my thoughts as well. I so want to get this started but I still need to get some 30" diameter sonotube and we'll the wood but the sub is oh so close.

This is my first build ever at least as far as speaker type of project. I know it needs to be air tight. The port is going to be somewhere between 8 to 10 inches which should keep the port speed down. For the port it's self I am going to use sonotube as well.

Anything else I need to think about?
phazewolf is offline  
 
post #14 of 40 Old 12-15-14, 02:14 PM
Elite Shackster
 
willis7469's Avatar
 
Join Date: Jan 2014
Location: minnesota
Posts: 3,945
My System
Quote:
phazewolf wrote: View Post
Anything else I need to think about?
Im not going against anybody's advice, cause I don't really have extensive knowledge here, so I'm kinda asking in a way. It seems to me that an fs of 21hz, would not lend itself to a 12hz tune. I know there's way more to it than fs, but I'm wondering what T/S parameters lend to an LLT. This is from their site.
http://www.istonline.ca/mach5_ftw_21.html
Parameters are at the bottom of the page.
willis7469 is online now  
post #15 of 40 Old 12-15-14, 03:03 PM Thread Starter
Senior Shackster
John
 
Join Date: Feb 2012
Location: Michigan
Posts: 324
My System
Send a message via Skype™ to phazewolf
I have seen this driver used in this way so it will work but I understand where your coming from with that. It models ok down to that point but if I understand correctly the lower you drop below fs the more over all spl you lose.

From a 16HZ tune to a 12HZ you lose like 6 db so the cost is great but I have around 6 dB of room gain starting around 25HZ so it would work out nicely.

And we'll if it does not I can cut it down and go sealed.
phazewolf is offline  
post #16 of 40 Old 12-15-14, 03:14 PM
Elite Shackster
 
willis7469's Avatar
 
Join Date: Jan 2014
Location: minnesota
Posts: 3,945
My System
But if you cut it down, how will you hide in it from your wife? Lol!
Are you gonna post build pics?
willis7469 is online now  
post #17 of 40 Old 12-15-14, 03:20 PM Thread Starter
Senior Shackster
John
 
Join Date: Feb 2012
Location: Michigan
Posts: 324
My System
Send a message via Skype™ to phazewolf
Well a sealed subwoofer will be a lot smaller and yes I will post pics.
phazewolf is offline  
post #18 of 40 Old 12-15-14, 07:02 PM Thread Starter
Senior Shackster
John
 
Join Date: Feb 2012
Location: Michigan
Posts: 324
My System
Send a message via Skype™ to phazewolf
It will be some time until I get a box built but here is the sub.

Ported how low is too low?-forumrunner_20141215_200212.png

That is a 2 L bottle to give you a idea on scale.
phazewolf is offline  
post #19 of 40 Old 12-15-14, 07:22 PM
HTS Senior Moderator
 
chrapladm's Avatar
Papi
 
Join Date: Jun 2009
Location: Adelaide, SA
Posts: 5,869
Re: Ported how low is too low?

Good things come to those with patience. I have been very slowly gathering parts for my builds and that has been about 1 year now. Still not ready to start building yet. So keep us updated when your ready.

Come to think of it there is another very slow build thread using a FTW and about 25cuft ported. Will have to find that thread. He is from Perth Australia I believe. There were some nice renders of the design also.

"Music is the space between the notes"
[T]o talk well and eloquently is a very great art, but that an equally great one is to know the right moment to stop.
chrapladm is offline  
post #20 of 40 Old 12-15-14, 07:25 PM Thread Starter
Senior Shackster
John
 
Join Date: Feb 2012
Location: Michigan
Posts: 324
My System
Send a message via Skype™ to phazewolf
I seen that thread a wile ago it did look nice. The sonotube is the thing I am having issue finding. Once I find that I can finish this in a few days.
phazewolf is offline  
Reply

Bookmarks

Tags
low , ported

Quick Reply
Message:
Options

Register Now




PLEASE COMPLETE ALL REQUIRED FIELDS BELOW... THANKS!

REQUIRED FIELDS ON THIS PAGE
YOU MUST COMPLETE ALL OF THESE

Username
Password
Confirm Password
Email Address
Confirm Email Address
Random Question
Random Question #2




User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
PLEASE READ BELOW PRIOR TO ENTERING AN EMAIL ADDRESS!

ATTENTION!

YOU MUST ACTIVATE YOUR ACCOUNT!

Activation requires you reply to an email we will send you after you register... if you do not reply to this email, you will not be able to view certain areas of the forum or certain images... nor will you be able download software.

AN INVALID EMAIL ADDRESS WILL CAUSE YOUR ACCOUNT TO BE DELETED!

See our banned email list here: Banned Email List

We DO NOT respond to spamcop, boxtrapper and spamblocker emails... please add @hometheatershack DOT com to your whitelist prior to registering or you will get nowhere on your registration.


Email Address:
OR

Log-in










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



Posting Rules  
You may post new threads
You may 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 is not allowed!
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


For the best viewing experience please update your browser to Google Chrome