Need some help tweaking ports on test box.

[Scotnemily]

Hi, I am in the process of putting together a sub and box combo for my car. After all the help I have gotten here I am probably going to end up with 1 15" SSA Icon. But until I get that taken care of, I wanted to build a different box for my current subs I am using. Right now they are in a sealed box each seeing 1 cuft. The sound quality is really good, music with a tight drum beat hits hard. Right now though I am not getting much sound below 30hz. I can play a 30hz test tone and it is loud, but it drops off quickly after that. Some of it could be a xover in my factory system cutting out the lower bass. not sure yet on that. There is no way I can adjust that if it is the case. I know the subs them self can get really low as I have used them in the past and never had any issues there. I was thinking it may be the box. While it is in spec for the subs, it is smaller than I have used before for them. And on the graph from the manufacture it would start falling off around the 30hz range. I want to build a ported enclosure for them to see if I am happy with the output. Who knows I might not even change anything else if I am. I will post the specs for the subs, manufacture recommended enclosure, and my box with the specs from BassBox.

Here are the specs for the subs.

Normal Power Handling 300W rms

Voice Coil Diameter 3”

Voice Coil Type / Former edge wound/Kapton

Resonant Frequency 43Hz

Qts-Total Damping 0.52

Qms- Mechanical Damping 2.51

Qes- Electromagnetic Damping 0.66

Vas- Equivalent Compliance Volume 43.97 Liter

DC Resistance of V.C. 4Ω / 8Ω

Sensitivity(SPL at 1W) 89.31 dB

Linear Excursion ±5.5mm

Peak to Peak Excursion ±13mm

Mms- Total Mass 114.7 grams

Sd- Piston Area 0.0512 sqM

Bl- Magnet Product 13.74 TM

Diaphragm Material carbon fiber/Nomex honeycomb

Basket Material cast aluminum

Net Weight 24.18lb

Dimensions 12.27” dia. X 4.75” H

Mounting Diameter 11.125” dia.

Here is the manufacture recommended box.

Basic working dimensions for thePRO12

Outer Diameter 12 9/32”

Mounting Hole Diameter 11 1/8”

Mounting Depth(from bottom of top ring) 4 1/4”

Speaker Displacement .098 cubic feet

Inside Volume 1.50 cubic feet

Internal Box Dimensions (LxWxD)

23 1/16” x 14 1/4” x 8 13/16”

Port Length 11 1/16”

Port Diameter 4” ID

Port Displacement .08 cubic foot.

Here is what I got from Bassbox.

For my port I think the two 4" ports would have an area around 25cuin my slot port has a little over 26 cuin

is that enough? Also I am worried the port is to narrow, should I go a little wider? I can post a image of the 3d model of the box too if that helps. I just want to make sure the specs look good for these subs or if I have overlooked something obvious. Thanks!!

Click to read more...

 

[Scotnemily]

Here are the images of the proposed box.

 

[Scotnemily]

Anyone?

 

[Hertz Mafia]

What subs do U have?

 

[Scotnemily]

Hi thanks for asking. They are the old flat ppi pro 12" 4 ohm subs

 

[Hertz Mafia]

https://www.sonicelectronix.com/item_17127_Precision-Power-PPI-PCX124-PCX-124.html

These woofers^?

Says sealed box. You can try ported and see what happens. Space makes bass. I would give them 2 cubes each after displacement tuned to 28hz if your trying to play low. But not sure what kind of music your listening to. Those woofers arnt really meant to play then low lows.

If your trying to bang out to 20hz music then get a sundown xv2 15 in a 5cube box tuned low 30-28hz.

 

[Scotnemily]

No they are the old ones. http://www.precisionpower.com/Manuals/Subwoofer%20Manuals/Precision_Power_PCPRO%20Series%20Subwoofers.pdf http://www.soundbuggy.com/ebay/pro12.html

If this box test does not produce the results I am looking for, I will be moving on to some SSA Icons either 2 12"s or 1 15". I just know from my past use of this sub, that it has no problem playing the notes I am looking for for the songs I am listening to. I know I ran more before, and I think they were each seeing around 2 cuft. don't remember though it has been to long ago.

 

[Scotnemily]

Also not really trying to be super loud in the 20hz range, but to give you a better idea of what I am working with 28hz is about 1/2 as loud as 30hz currently and 25hz is about 1/2 as loud as that. There is a huge slope I am fighting and i think it is the box i am using.