Attn Autophiles: I need to port my sub box - help plz

[chuzie]

So I acquired a 11" Memphis sub in a sealed sub box measuring W=8" (bottom) tapering to 5" (top) x L=24" x H=16".

The problem is, in my open air Bronco, it does not produce the level I am looking for as it came out of a Honda Accord.

Can I port this box to help unleash some of the sub's potential?

If so, what shape and size port should I use?

Thx.

 

[broncnaz]

Usually non ported sub speakers dont respond well to a ported box. You can try if you want but I think you may just need a different sub. Its not only a port factor its also the size of the box factor ported boxes are usually larger all around than a sealed box. There can also be differances in the actual speaker design that is used with seal and ported boxes so a seal speak may not sound all that great in a ported box and vice versa.

 

[chuzie]

Well crap. I had no idea there was a difference. Maybe I will sell it on CL.

Thanks.

 

[bronconut73]

Porting it will make it perform really well at a limited frequency range and poorly at most other bass frequencies. Bass is a fickle beast in open top vehicles.
Sealed is probably what you should stick with.
Perhaps your not putting enough power into that Memphis Sub. What amp are you running on it?

 

[74strokerbronco]

I have bass box pro6 here somewhere and if you can give me the exact model of sub or a full set of thiel parameters for your subs I can see what it tells me, it will model pretty well. I build all my subs and speakers using it to model and all have been awesome so far. Many so called sealed enclosure subs will still work great in a ported config but as stated you usually see some gains around a certain freq and losses in others but its a sub and pretty easy to get a fairly flat curve from 40-120hz.

 

[chuzie]

I don't know squat about audio so y'all are going to have to spoon feed me.

Here is the amp

And, of course, the sub has zero info on it.

 

[AaronWelch]

I would say you are probably under driving the sub. I would be willing to bet you could double the output of the amp and still barely make that sub work well. Do you have a decent component stereo in the house? You could hook up the sub to it and see how it sounds.

 

[lowbush]

If I am reading that correct that amp is putting out 50W per channel which means that speaker is way under-driven. I know enough about audio to be dangerous so I would confirm with one of the guys that does a lot of audio, but I don't think you are putting enough power to the speaker.

 

[chuzie]

Ugh. So I need a different amp? No stereo inside. Can I assume that am is good for nothing more than driving my mids and highs?

 

[BRONCROB]

Is that your sub box in the picture?It looks like a standard pickup box designed to go behind the seat.They really aren't designed with sound in mind as much as fit.You could bridge the amp and try fireing the sub off the tailgate or in a corner for somewhat better sound but it's not going to sound great in that box.You may want to look in to building a new one.Oh and bridging that amp should put you around 150w which should be plenty for a single sub.

 

[chuzie]

What size box and ports, if any, would be needed?

Also, what the hell is and how do I "bridge."

 

[BRONCROB]

Bridging is simply connect the + of either the right or left channel,depending on the amp,and the - of the other channel to gain more power.Here are some ideas for enclosures. http://classicbroncos.com/forums/showthread.php?t=205477

 

[BRONCROB]

Another cool idea. http://www.google.com/search?q=fuel...qNEo-gyATHwIHoDA&ved=0CCYQsAQ&biw=320&bih=455

 

[chuzie]

Gas cans eh? Awesome!

Step one will be to determine required enclosure size. How can I determine what this sub is if there are no identifying markings?

 

[chuzie]

This is the closest thing I could find on the Memphis site.

Mounting Depth (in) 5.54
RMS / Peak (w) 250 / 500
Sensitivity (dB) 86
Size (in) 12
Magnet Size (oz) 60

 

[bronconut73]

In a perfect world you would put a 500+ watt amp on that sub and let it eat.
But anything over 250 would work well.

 

[BRONCROB]

Looks like a 10"? Memphis sub? A 10 is happy with about 1-1.5 cubic ft. of volume.I can't recall off hand the formula but here's a calculator http://www.calculator.net/volume-calculator.html .The larger metal jerrycan would probably be ok with something to stiffen it up and some dynomat and polyfill inside.

 

[Grunt1058]

Sealed speakers/boxes are designed for closed vehicles (windows closed, doors closed, trunk closed). The air tight cabin is essential for not blowing the subs.

 

[chuzie]

How do I correctly measure the sub size?

 

[BRONCROB]

Should be just the cone and rubber surround.That looks like a 10 but I would have to measure mine to know for sure on exact measurements.