Quarterwave box for 2 12" re srx's

 

Silver Member
Username: Slimdog53185

Bowling Green, Kentucky U.S.

Post Number: 102
Registered: May-07
I'm thinking of building a quarterwave box for my srx's. Ineed some more info on it then I found by searching. How does the port need to be exactly? I know its really long, but is there a minimum size height and width wise? How much cuft do I need for just the subs.? I've seen some boxes that look like one big port.

What are the benefits of of the 45 corners again?
 

Gold Member
Username: Somedonniedude

Illinois Braaap MX

Post Number: 3014
Registered: May-07
There is no "box volume" with quarter waves. Generally you tune them to the Fs of the driver and the port area is around 75% of your woofers sd.

I did a bunch of research on tl's awhile ago, and many people swayed me away from the idea of it in car audio use. i'd still like to build one someday for car use, but i've got too many projects as it is lol.
 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12924
Registered: Dec-03
for a 12" sub the box will not really be reasonable in length for a car, unless you are putting this into an extended length cargo van.
If you want an accurate box for a car, go with aperiodic instead of quarter wave transmission line. a TL box will extend the low end, but honestly in a car you're not coing to hear the difference in coloration anyway. you can't even hear distortion in a woofer below 10%. That's why class D amps work so well for subs, combined with the lower frequencies not requiring the amps to transistors to switch as quickly as they would for higher frequencies.

I've built transmission line home speakers, but those are typically using a 6" or 8" driver at the most, and they are still rather tall speakers.
 

Silver Member
Username: Slimdog53185

Bowling Green, Kentucky U.S.

Post Number: 103
Registered: May-07
What is aperiodic? I've never heard of that. Is there any other enclosure that would be good for them?
 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12929
Registered: Dec-03
http://diyaudioprojects.com/Technical/Aperiodic/


 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12930
Registered: Dec-03
http://www.audiogearreviews.com/tech/theory/enclosure_design/aperiodic_membrane. asp

and on TL boxes

http://www.diysubwoofers.org/tls/
 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12931
Registered: Dec-03
http://www.teamaudionutz.com/tutorial/1/AP_Enclosures-The_Aperiodic_Cookbook
 

Silver Member
Username: Slimdog53185

Bowling Green, Kentucky U.S.

Post Number: 104
Registered: May-07
I'm just looking for something loud as possible but still good for music. I'm replacing a 3.2cu ft tuned to 33Hz box. The aperiodic seems to be more for SQ.
 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12935
Registered: Dec-03
It is. So is a 1/4 wave TL box.

If you want loud, stick to ported or bandpass.
 

Silver Member
Username: Slimdog53185

Bowling Green, Kentucky U.S.

Post Number: 105
Registered: May-07
Can you recommend a size and tuning for me? I don't think I have the room for a bandpass box, but I can do ported for sure. The box they are in just doesn't sound right to me.
 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12939
Registered: Dec-03
try 2.0cu ft per sub, shared chamber, after driver and port displacement.
use one 4" inner diameter aero port per sub
tune the ports to 32Hz.
 

Silver Member
Username: Slimdog53185

Bowling Green, Kentucky U.S.

Post Number: 106
Registered: May-07
So still use two round ports. What about a slot port?
 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12943
Registered: Dec-03
slot ports are good if your goal is SPL, but they lack the punch of a smaller round port at lower volumes, in my experience.
 

Silver Member
Username: Slimdog53185

Bowling Green, Kentucky U.S.

Post Number: 107
Registered: May-07
You know any tutorials of box building? Like what size box for what and what port is good for what. I've just been going by manufacturer recommendation.
 

Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 12949
Registered: Dec-03
try this
http://www.diysubwoofers.org/
 

Silver Member
Username: Slimdog53185

Bowling Green, Kentucky U.S.

Post Number: 108
Registered: May-07
I figured about 33x13x22 w/ 2 4x13 ports. That should be about what you suggested. Does that sound right? What about 45s in the corners how would I calculate for that?
 

Platinum Member
Username: Rovin

1 15 = 152.5 DBs ...Trinidad & T...

Post Number: 16175
Registered: Jul-05
45s in the corner shapes up to be what ? - a triangle so all u have to is cal the volume of a triangle & take it into acct when doing the final design

use this as a guide

http://www.the12volt.com/caraudio/boxcalcs.asp

http://www.carstereo.com/help/Articles.cfm?id=31 ...
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