posted
what driver parameters should i be looking for to pick out an ABC driver? low Qts? low Qes?
Posts: 1467 | From: eureka, ca | Registered: Aug 2001
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posted
How do you go in finding which size box to use? For example, the JL 12w3 says ported can go anywhere from 2-3 cubic feet. What size would be optimal? Does size only determine loudness, or does it also affect SQ?
Posts: 20 | From: Bay Area | Registered: Oct 2001
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Mr. Flamboyant have you ever tried a dual-reflex bandpass, if so how would you say ABC's compare to one?? Why can you not break the 2:1 ratio or play with the ports abit. Subs with low EBP such as 12W3's require a large box in your opinion is this due to the fact that you need a big box to get a flat response in a regular ported box. What does an ABC sound like with a box that is too small. What would you expect the powerhandling to be for a 12w3 in a 4.5 cu. ft. box compared to a 2.5 cu. ft. as reccomended by jl. Do the pair of ports limit excursion that much better?? I've never built one but i'm thinking of going with one for three concept EX-12's rather than a dual-reflex bandpass. I think these subs will work beautifully in an ABC. I don't have the T/S parameters but off the top of my head i believe they are. Qts: 0.40 Fs: 26.9Hz Vas: 2.8 cu. ft. Spl: 86.9dB
Also i remember you asking for more info on LSPcad. It's a program that will plot quite a few boxes (including ABC and even another box like an ABC but with no port on the smaller chamber to the outside of the box) with tons of functions (impedance, port speed group delay, etc.). It's not freeware like winISD but there is a fully functioinal free version but you cannot add any drivers to it howeever. But it's fun to play with to learn about the freq. curves of different boxes and what happens when you change different aspects of the box (also it's nice to know impedance curves). Here's a link for some info on it. http://www.libinst.com/LspCAD.htm there's a new version 5.0 out as well. Also version 1.0 is fully functional and you CAN add drivers to it. However the only box types are sealed, ported and bandpass (sorry no ABC). But it gives you impedance and port speed curves. (which winISD does not). However i feel as if winISD is the easier box plotting program to use. I remember when i told you about winISD about a year ago on carsound (my name is Ross over there) when you were running your 18" audiobahn off a D2. Sorry for the long post there was just so much i've been delaying to say before jumping into this post, 9 pages and 400+ posts later i feel like i have some catching up to do.
posted
I can just see the fight to get it (1000th post, I've never seen it happen on ANY board). There's going to be ~10 posts all within the same minute.
Posts: 164 | From: USA/Canada | Registered: Feb 2001
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posted
the difference between 6th order and ABC, is the 6th order has the sub buried inside of it.... and only the pressure comming from the ports will move air....
with the ABC, the ports, AND the effective area of the moving cone, will create displacement..... basically, it can be quite a bit louder....
additionally, the 6th order doesnt have the ability to utilize the "power" of both chambers combined.... the effect of the BIG box, and a lot of port equals HUGE power efficiency, and insane levels of output (even with only, say, 36 square inches of effective port area, per sub).... in a 6th order, you would have to make the large chamber as big as the entire ABC (both chambers)...then for the smaller chamber of the 6th order, you would need to make that about half the size of its larger chamber.... so basically a 6th order needs to be 1 1/2 times the size of an ABC.... (to sound as good, in my opinion)
i figure if you can do a 6th order, you can figure out an ABC....
hope this helps,
-Wes
-------------------- - Wes Sowers - Discount Car Stereo L.L.C. Kent, Wa 98032 (206)824-5875
posted
ok, quick questin, need some hlpe with an abc box for a orion xtr3 12"dvc. i dono exacly how to make the box, but ihave a good idea. thankx.
Chris
-------------------- Founder of team NOIZE FACTORY Member of Team Gates Beliver of ABC boxes Clarion DXZ555MP Head Unit 1 HUGE ABC box Dissapointing 148.7 AC190 Mic
posted
Have you heard a 6th order?? How would you say it compares to an ABC (Transient response, SPL etc. etc.) I'm going to have to disagree with you on an ABC being "Louder" in theory, in a 6th order bandpass, both the front and the rear wave coming off the sub will be "tuned by the port causing resonance and boosting output. In the case of an ABC only one wave is (like a ported box). Also a 6th order is very versatile. You can tune it for an extremly wide band or for a narrow (but crazy loud) bandwith. But then again this is all theory. Have you tried a sub in both an ABC and a dual-reflex bandpass. (the same sub) What were your impressions of both?? Also how well do you find subs with an EPB of lower than 50 work in an ABC. I know from experience that these subs work much better in a single-reflex bandpass compared to a dual-reflex and I was just wondering if it's the same for ABC's.
Posts: 164 | From: USA/Canada | Registered: Feb 2001
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posted
ok.... lets take a quick look at these 2 boxes....
an ABC, and a 6th order.
lets say they are both 6 cubic feet total.... the chambers of each box are 4 cubes, and 2 cubes.... both boxes have the same amount of effective port area, say 5" diameter pipe (40 square inches total usable area, for each box)
6th order- on the low notes, bass will only come from the 4 cube chamber, and 20 square inches of port.
ABC - low notes will come from 6 cubes worth of airspace, and 40 square inches of port... PLUS the sub is moving air too!!! theoretically, thats a MAJOR difference in output (real life = night & day)
6th order - higher frequencies will come from the 2 cube chamber, and 20 square inches of port.
ABC - higher frequencies will also come from the 2 cube chamber, and 20 square inches of port, but PLUS the subs cone is moving air too... this too is a noticeable difference in output.... clarity/accuracy/tonality are all as good, if not better than 6th order.... the subs cone being exposed to the cabin/your ears has a lot to do with this
IM NOT TOO SURE, but i think subs that are inside 6th order boxes CAN have "phase" issues.... where the sub has to change a certain amount of degrees, when changing frequencies????????? again, not too sure about 'phase' problems that can be associated with 6th order boxes, but i do know that it is not commonly associated with ABC's....
i have tried a 6th order once, and i wasnt all that impressed.....
i tried an ABC once, and i have never been the same since.... VERY impressive.... i've built over 20-30 since then....
im NOT saying the ABC box is the best box ever thought-up... im saying its not too damn shabby though!!!
anyway, thanks for reading, hope it helps...
-Wes
-------------------- - Wes Sowers - Discount Car Stereo L.L.C. Kent, Wa 98032 (206)824-5875
posted
The Efficiency Bandwidth Product (EBP) number ROUGHLY indicates which type of box enclosure that a particular driver was PROBABLY designed for. It is intended to be a quick rule of thumb reference. Generally, if the EBP is 55 or lower, then the driver should be used in a closed (or 4th order bandpass) box. If the EBP is 56 or higher, a vented (or 6th order bandpass) box should be used. However, these are not hard and fast rules...if the EBP is close to the "borderline", then it should perform equally well in either type of box.
For you number crunchers out there, EBP is calculated by using the drivers' Fs and Qes as follows:
Fs/Qes = EBP
subs with an EBP in the 50's is the only way to go..... and i like the "small box" type subs for ABC's also... makes them somewhat feasible for the mobile environment...
just want to note that parameters are just a parameter.... and dont really amount to a hill of beans till you actually get it in the car, with watts going through it..... this will ultimately determine the final "sound" that arrives at your ear(s)....
let me know if there's anything else i can help with
-later
-------------------- - Wes Sowers - Discount Car Stereo L.L.C. Kent, Wa 98032 (206)824-5875
posted
I just got a crazy idea, what about an ABC bandpass. It works like a 6th order bandpass except the rear chamber is an ABC box rather than just a ported box. Mr. Flamboyant, what subs have you heard in an ABC and what were your impresssions. What would you reccomend as a good ABC box for these drivers. Concept EX-12: Qts: 0.40 Fs: 26.9Hz SPL: 86.9dB Vas: 2.8 cu. ft.
What sub did you try in a dual reflex bandpass?? What were the specs.
Also ported boxes (including ABC) have the same problem with phase as DR bandpasses. This is why they roll off at 24db/octave At tuning the waves are in phase and therefore give you large gain as the driver starts to play lower than the port they start to go out of phase therefore cancelling each other out.
Also ported boxes (including ABC) have the same problem with phase as DR bandpasses. This is why they roll off at 24db/octave At tuning the waves are in phase and therefore give you large gain as the driver starts to play lower than the port they start to go out of phase therefore cancelling each other out.
thank you for clearing that up
the sub i tried in 6th order was an Audiobahn AW1505.... the large chamber was 3 cubes with a 4" round x 8.5" long.... the smaller chamber was 1.5 cubes, with a 4" round x 8" long vent... just didnt get as loud as an ABC did....
i would suggest about 5 cubes of net airspace (total, both chambers, after displacements) with about 30 square inches of total effective port area, for the concept, and kicker sub....
i wanna see some results of other peoples work now... im about BURNED OUT!!
-Wes
-------------------- - Wes Sowers - Discount Car Stereo L.L.C. Kent, Wa 98032 (206)824-5875
