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View Full Version : Should I learn my ABCs or just stick with the basics?



Harrison486
06-02-2005, 11:03 AM
Hey guys! What's going on?

Alright. Right now, my 2005 12" Kicker CompVR is in a pre-fab sealed 1.25 cf Q-logic box.

I am thinking about building a new ported box. I was thinking about this design (I dont even know if its any good or anything for a daily driver. What do you think?)
http://img7.echo.cx/img7/8472/boxdesign0du.th.jpg (http://img7.echo.cx/my.php?image=boxdesign0du.jpg)

Anyway, I was doing some research, trying to figure out if this box would be any good. While doing it, I came across a box design called an ABC box. Anyone know anything about it? Here are two pictures:
http://memimage.cardomain.com/member_images/2/web/338000-338999/338577_313.jpg
http://images.cardomain.com/member_images/2/web/530000-530999/530958_19.jpg
It was described like: "One of the best enclosure IMO is the ABC Box. It'll make any subwoofer sound amazing. Your sub will get extremely low without loosing high end extension. If you've never tried an ABC Box, you're missing out. Believe it or not, even one crappy sub...can sound very very good...and will astonish your ears. The only drawback is the size of the enclosure. This is not an SPL enclosure...it's an SQL box.

The enclosure consists of 2 Chambers (woofer chamber & empty chamber). There are 3 ports in total...all the same length. "

Does anyone know anything about ABC boxes? Is it worth figuring out how to build one over just building a ported box? It seems like the ABC box offers the bext of both worlds, the volume of ported, and the SQ of sealed. I dont understand why more people haven't used them. (I searched and only found one person who tried to build one for a car)

So should I attempt an ABC box or is it not going to offer anything over the planned ported box?

Thanks

Nikuk
06-02-2005, 12:00 PM
they are great boxes depending on Your listening taste. they also require a bit of space. I'd definately suggest trying one. lots of output across the freq range in my experience.

-Nick

$0.02

req
06-02-2005, 12:07 PM
id love to learn, but where to find out how is a different story - its hard enough learning how to port a box CORRECTLY, now we are getting into the realm of horns, t-lines, ABC's and all tha t good stuff.

Nikuk
06-02-2005, 12:09 PM
ABC's are ****ing cake. there is a 15ish page long thread at termpro that'll teach You, if You if You cant figure it out.

-nick

req
06-02-2005, 12:12 PM
care to link? im up for a good read.

the_noob
06-02-2005, 12:26 PM
care to link? im up for a good read.

I found a bunch of links, but they were all dead. However, I did find this.


Ok, here it comes one time! I only explain these in detail once a year (I make $$ on them )
For that DVC 15. Build a box with 2 chambers, one at 3 cuft and the other one EXACTLY half of that, ie 1.5 cuft. Next cut 3 ports all IDENTICAL in length. Put one in the face of each chamber and the third in the wall separating the two chambers. In this instance each port would be either 12.5" long for a little deeper response or 8" long for a little more SPL.
Now you have a box with a big chamber with a vent in it, a small chamber with a vent in it, and a third vent in the wall between the two. The woofer also mounts in the large chamber.
The way they work is that, at low frequencies, it all functions as one big box with 2 ports, and is tuned to 30Hz (12.5") or 35HZ (8"). At higher frequencies the middle port starts to restrict air movement and the second chamber begins to act more as a resonance chamber but not as part of the box. At this point a second tuning frequency develops 1.9 times (almost an octave) higher than the lower one , ie. either at 57Hz (12.5") or 67Hz (8").
This is similar to a vented bandpass but has more output and smoother sound due to the woofer not being tucked inside the box. The results are that it plays both low and loud, while being relatively nice sounding. The drawback is the box size.

Did one 2 years ago in a sedan with 1 12 on 400 watts and pulled a 138 on music. There's a guy around here with 2 DVC 15s like this in a Daytona off a single 800a2 pulling 149s.
They work but can be intense to build. They are the ONLY box I take care to factor exactly both port displacement and woofer displacement. Mess one of these up and they work very poorly....

Looks simple...

Harrison486
06-02-2005, 12:32 PM
First, let me explain my musical tastes and how much room I have

I listen to almost exclusively rap and hip-hop.

The max dimensions of my box can only be 14" high, 36" wide, and 36" deep, although that would be my entire trunk

What do you think I should do?

What that ported box I posted above be fine?

Or does an ABC box really outperform a ported box?

Nikuk
06-02-2005, 12:33 PM
exactly.

yes it really does tune by the octave.
yes it really does unload the middle port at certain ranges.
yes it really works as a bi-tuned ported.

That is from TP, a la` "Dukk" iirc.

Git er done...

Nikuk
06-02-2005, 12:34 PM
for mainly rap & hip-hop... just go big ported low tune.

$0.02

bumpin_blazer
06-02-2005, 12:58 PM
ABC's to me are a waste of time and space due to their size with real lack of SPL gain. I've built one for my SI D2 12" when I had it. Tried that sub in sealed, ported, ABC, and 4th order bandpass. The ported wasn't as loud as bandpass but louder than ABC and 1/2 the size. ABC's give a great response at many different frequencies where as ported give's you a nice kick at a certain 5-10hz or so. How I usually just guess it at is like this, a ported box has a theoretical 5db's over sealed, so I just would say that an ABC enclosure has about 3db's on sealed, well in my experience that is.

the_noob
06-02-2005, 01:05 PM
ABC's to me are a waste of time and space due to their size with real lack of SPL gain. I've built one for my SI D2 12" when I had it. Tried that sub in sealed, ported, ABC, and 4th order bandpass. The ported wasn't as loud as bandpass but louder than ABC and 1/2 the size. ABC's give a great response at many different frequencies where as ported give's you a nice kick at a certain 5-10hz or so. How I usually just guess it at is like this, a ported box has a theoretical 5db's over sealed, so I just would say that an ABC enclosure has about 3db's on sealed, well in my experience that is.

But did you lose any SQ going ported?

I don't believe that ABC boxes are really meant to be louder than ported, just kind of like a loud SQ box (at least from what I've read so far), right?

bumpin_blazer
06-02-2005, 01:12 PM
But did you lose any SQ going ported?

I don't believe that ABC boxes are really meant to be louder than ported, just kind of like a loud SQ box (at least from what I've read so far), right?

Sq is relative so that's a hard question to answer. Then again, I did tune the ported box to 32hz so that keeps it IMO sounding as good as sealed from 26-40hz.

req
06-02-2005, 01:20 PM
ABC's are ****ing cake. there is a 15ish page long thread at termpro that'll teach You, if You if You cant figure it out.

-nick

so care to post a link for the commonwealth?? :laugh:

bumpin_blazer
06-02-2005, 01:26 PM
so care to post a link for the commonwealth?? :laugh:

ABC's truely are simple. As stated say your sub needs a 3cuft ported box. Make yourself a box that is a total of 4.5cuft with a board that cuts the box into 2 chambers of 3cuft where the sub will be mounted, and 1.5cuft where the other port will go. You then take 3 pvc pipes cut and made to your desired tuning length and drop em' in da box. The tubing is the hard part but even then if you're good at ported box's it isn't hard;).

req
06-02-2005, 01:33 PM
wait wait.

so i would do the port length depending on a SINGLE 3" port (say winISD) or 3 3" ports?

because how the hell do you get the length :p:

i understand the 1:1\2 box size ratio. i under stand how it works and how to build them. but how do you measure the tuning versus port length on these - since there are 3 ports.

Harrison486
06-02-2005, 01:53 PM
So I am still confused....

ABC or Ported for me?

Also, ported is louder in a certain frequency range than sealed, right? What about the frequencys above the tuning point? Is that just same spl as sealed just worse quality?

Nikuk
06-02-2005, 03:04 PM
ABC's to me are a waste of time and space due to their size with real lack of SPL gain. I've built one for my SI D2 12" when I had it. Tried that sub in sealed, ported, ABC, and 4th order bandpass. The ported wasn't as loud as bandpass but louder than ABC and 1/2 the size. ABC's give a great response at many different frequencies where as ported give's you a nice kick at a certain 5-10hz or so. How I usually just guess it at is like this, a ported box has a theoretical 5db's over sealed, so I just would say that an ABC enclosure has about 3db's on sealed, well in my experience that is.

ABC boxes are not SPL boxes by any means, unless You are very tricky with the tuning.

Where the hell do You get these theoretical gains?


ABC's truely are simple. As stated say your sub needs a 3cuft ported box. Make yourself a box that is a total of 4.5cuft with a board that cuts the box into 2 chambers of 3cuft where the sub will be mounted, and 1.5cuft where the other port will go. You then take 3 pvc pipes cut and made to your desired tuning length and drop em' in da box. The tubing is the hard part but even then if you're good at ported box's it isn't hard;).

You are supposed to(in theory) DOUBLE the recommended enclosure, then multiply by 0.66 & 0.33. However, I've done varying sizes from 1/2 vas to 3x vas.

[/meh]

REQ - {search function} N00b :lol:

Nikuk
06-02-2005, 03:06 PM
So I am still confused....

ABC or Ported for me?

Also, ported is louder in a certain frequency range than sealed, right? What about the frequencys above the tuning point? Is that just same spl as sealed just worse quality?

You are asking for opinions on sound quality & accuracy.... EVERYONEs answers will be a little different.

IMO - ported if all You are doing is listening to bass heavy rap.

[/nick]

req
06-02-2005, 03:07 PM
oh cmon nick. you know where the link is. its not really a big deal to me. i dont plan on making any ABC's anytime soon.

if you dont wanna post the link. whatev. :p:

Beat_Dominator
06-02-2005, 03:07 PM
Me wanty link too :p:

Harrison486
06-02-2005, 03:12 PM
Also, ported is louder in a certain frequency range than sealed, right? What about the frequencys above the tuning point? Is that just same spl as sealed just worse quality?

Can someone explain to me how a ported box works.. Or how it differs from a sealed...

Beat_Dominator
06-02-2005, 03:16 PM
In the most bassic sense, the volume of air inside the port/s acts like a passive radiator, you're kind of adding a sub to the real one that's there.

the_noob
06-02-2005, 03:18 PM
You are supposed to(in theory) DOUBLE the recommended enclosure, then multiply by 0.66 & 0.33. However, I've done varying sizes from 1/2 vas to 3x vas.

Do you double the recommended sealed enclosure size or ported enclosure size?

Harrison486
06-02-2005, 03:21 PM
In the most bassic sense, the volume of air inside the port/s acts like a passive radiator, you're kind of adding a sub to the real one that's there.

Okay...

But what I am confused about is

Ported is louder tahn sealed since you are getting the sub output plus output out of the port. Is it louder across all frequencies or just a certain range due to tuning? If it is the latter, what about the rest of the frequencies? Does it just act like a sealed box for the rest?

Nikuk
06-02-2005, 03:22 PM
Do you double the recommended sealed enclosure size or ported enclosure size?

recommended ported.

Again, I have found no reason for this in any of the cookbooks or on the websites. But it's not a bad rule of thumb.

For what it's worth.

Beat_Dominator
06-02-2005, 03:25 PM
Okay...

But what I am confused about is

Ported is louder tahn sealed since you are getting the sub output plus output out of the port. Is it louder across all frequencies or just a certain range due to tuning? If it is the latter, what about the rest of the frequencies? Does it just act like a sealed box for the rest?

It would be louder across most of the freq. range that the driver can reach. A bandpass box is the one that would cut you off.

bumpin_blazer
06-02-2005, 03:25 PM
ABC boxes are not SPL boxes by any means, unless You are very tricky with the tuning.

Where the hell do You get these theoretical gains?



I've heard them from about 10-20 people I know that compete as a general guess for noobie types on if someone says "what kind of a gain can i expect from ported over sealed."

again it's all theory though, well that or hypothetical if you'd like:D.

Raven
06-02-2005, 08:14 PM
*sigh* Noone is willing to help anyone anymore..

http://www.diysubwoofers.org/prt/dual_chamber.htm

Our RE rep around here has done some work with RE8s, ABC boxes, and less than 180 watts. In his own words, his first reaction to the output was "Holy ****!". You can guess they have something good going for them.

the_noob
06-02-2005, 09:06 PM
thanks Raven. ;)