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wo for 12s a lil help please. (Read 7805 times)
60ndown
Ex Member



wo for 12s a lil help please.
06/09/06 at 02:26:51
 
looks like im buying more mdf Wink going to build a wo for 2 x 12s, questiuon is this,
with all you guys knowledge, would you build it 36x36x14 or, scale it with the same ratio a 10 is to a 12, ie multiply all dimensions by 1.2 (or the surface area difference?)

im leaning towards scaleing the whole thing because it sems right to build the thing a bit bigger for a bit bigger sub, trying to squeeze a 12 into a box made for 10s seems silly 2 mi. wadda you think and why?
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J_Rock
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Re: wo for 12s a lil help please.
Reply #1 - 06/09/06 at 02:46:56
 
From the guy shouting "Don't Mod Steve's Designs..."

I would follow steve's plans then.  Add 2 inches.

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Gex
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Re: wo for 12s a lil help please.
Reply #2 - 06/09/06 at 04:13:19
 
same here
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60ndown
Ex Member



Re: wo for 12s a lil help please.
Reply #3 - 06/09/06 at 06:02:40
 
[quote author=J_Rock  link=1149820011/0#1 date=1149817616]From the guy shouting "Don't Mod Steve's Designs..."



[/quote]

not modding it, building it the same, just bigger?
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djman37
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Re: wo for 12s a lil help please.
Reply #4 - 06/09/06 at 22:28:58
 
I built UP and love it. Grin
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bassboy
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Re: wo for 12s a lil help please.
Reply #5 - 06/11/06 at 02:46:15
 
60, you could probably do it either way with success.  But at the same time I would try to leave the horn flare alone.

If you want a guess, I'd say it was designed the way it was because that is the design that was most successful for 10 inch drivers.  Adding two inches in height changes the horn enough as it is, expanding all dimensions by 1.2x would make further significant changes.

I am very wary to take liberties with the horn part.  It works more like a high efficiency, low distortion, wide range port than a horn, in my estimation.  Making it significantly longer might make it act more like a horn, and that's not good for a horn this size.

I think there are reasons that 15's and 18's are not recommended.  I think scaling the height alone makes too much change to the horn section and not enough in the driver chambers.

Remember that this is just a guess, but I think the box was made specifically for 10 inch drivers but happens to be flexible enough to accomodate a couple of inches either way with good results.

So I don't think you should change the horn more than you have to.  But you can probably safely change the chambers that feed the horn.  Make the chambers bigger (the sealed chamber mainly) and the tuning of the chambers will lower.

This is all just speculation but it seems to me that the further you deviate from the plans without understanding the implications, the more risk you are taking.  It's all at your own risk.
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Gex
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Re: wo for 12s a lil help please.
Reply #6 - 06/11/06 at 04:24:40
 
60
remember awhile back somebody was going to modify the WO so the sealed chamber was bigger or a mod of some sort that left a triangular hump to the top lid.
I wonder what came of it? I don't remember who and threads were disappearing back then.

I would not mess with the "horn part" I would add 2" I think thats what Big air used and it worked, but correct me if I am wrong.

how about you try a 12" WO32 and let me know how it works, nobodys done it yet that I know of.
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60ndown
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Re: wo for 12s a lil help please.
Reply #7 - 06/11/06 at 05:53:06
 
[quote author=bassboy  link=1149820011/0#5 date=1149990375]60, you could probably do it either way with success.  But at the same time I would try to leave the horn flare alone.

If you want a guess, I'd say it was designed the way it was because that is the design that was most successful for 10 inch drivers.  Adding two inches in height changes the horn enough as it is, expanding all dimensions by 1.2x would make further significant changes.

I am very wary to take liberties with the horn part.  It works more like a high efficiency, low distortion, wide range port than a horn, in my estimation.  Making it significantly longer might make it act more like a horn, and that's not good for a horn this size.

I think there are reasons that 15's and 18's are not recommended.  I think scaling the height alone makes too much change to the horn section and not enough in the driver chambers.

Remember that this is just a guess, but I think the box was made specifically for 10 inch drivers but happens to be flexible enough to accomodate a couple of inches either way with good results.

So I don't think you should change the horn more than you have to.  But you can probably safely change the chambers that feed the horn.  Make the chambers bigger (the sealed chamber mainly) and the tuning of the chambers will lower.

This is all just speculation but it seems to me that the further you deviate from the plans without understanding the implications, the more risk you are taking.  It's all at your own risk. [/quote]

thanks for the thoughts, if you have anymore before monday / tuesday let me know.dont horns get better the longer they are? more throat to controll the wave? i know nothing Cheesy
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Adrian D.
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Re: wo for 12s a lil help please.
Reply #8 - 06/11/06 at 07:01:59
 
[quote author=Gex  link=1149820011/0#6 date=1149996280]60
remember awhile back somebody was going to modify the WO so the sealed chamber was bigger or a mod of some sort that left a triangular hump to the top lid.
I wonder what came of it? I don't remember who and threads were disappearing back then.

I would not mess with the "horn part" I would add 2" I think thats what Big air used and it worked, but correct me if I am wrong.

how about you try a 12" WO32 and let me know how it works, nobodys done it yet that I know of. [/quote]
hmmm, Jrock said that using high excursion drivers (rl-p has 24mm xmax) in front loaded horns might not have good results. at least not at high power.
60, did you manage to find another rl-p ?
too bad mike doesn't sell rl-p 10s Sad
it would surely be a great choice for a wo.
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60ndown
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Re: wo for 12s a lil help please.
Reply #9 - 06/11/06 at 13:27:15
 
[quote author=Adrian D.  link=1149820011/0#8 date=1150005719]
hmmm, Jrock said that using high excursion drivers (rl-p has 24mm xmax) in front loaded horns might not have good results. at least not at high power.
60, did you manage to find another rl-p ?
too bad mike doesn't sell rl-p 10s Sad
it would surely be a great choice for a wo. [/quote]

yes i will be useing 2 x rl-p in my new w.o.i hope the high excursion isnt an issue, perhaps if i open the throat just a little from 1.25" too 2". i cant think why a scaled version for bigger subs would perform any differently than the standard version with smaller subs?, other than it 'should' play louder and lower?
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Adrian D.
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Re: wo for 12s a lil help please.
Reply #10 - 06/11/06 at 14:08:18
 
i'm pretty sure it won't pose any problems. just ask on ssa about a reccomended port area for the rl-p12. the wo provides 17 sqin of port area if the opening is 1.25" * 14". should be enough.
i don't think scaling up will play a lot lower. THAT would be messing with the design.
just how much sealed volume does the wo offer ?
recomended sealed box for the rl-p is around 1.25 cf.
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J_Rock
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Re: wo for 12s a lil help please.
Reply #11 - 06/11/06 at 15:21:22
 
WRT high excursion drivers in horns:  The problem high excursion drivers had were with the use of compression chambers like the WO has.  They tend to muddy the bass when used.  

60 sounds like the kind of guy that will be turning it up full blast occasionally, just to show off or impress.  So in his case, I doubt the high excursion will pose a problem.

I would just stay away from high excursion drivers in compression chamber style horns if they are to be used at high output for most of their lives.  There are better designs that won't produce the muddienes.(sp)

Case in point, the WO32.  No compression chamber, and at the loss of a little output, it performs better with more speed and accuracy but with a close to equal ability to go low.
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J_Rock
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Re: wo for 12s a lil help please.
Reply #12 - 06/11/06 at 15:29:29
 
Sorry for the second post.

In regards to useing the recommended sealed enclosure volume, vented enclosure port area etc.

You cannot expect to know what the WO will do for your sub while just compareing the recommended enclosure specs to the WO.  Changing one thing on the WO, like throat size, will result in a different animal. (Steve recommends opening the throat more for the WO to play High Frequencies better.)

Messing with the chamber sizes will change the Q of the box and make it sound boomier or more quiet.

The only way to get a good representation would be to model a 4th order BP tuned to 45 Hz with the chambers the same size as the WOs.  This is what Steve suggests, and what has worked for me in the past.

So what does this mean?  Well 60, if you want to decide to scale or to add 2 inches:

Model the 4th order BP tuned to 45Hz with both changes done.  It won't compensate for the different horn dimensions, but it will give you an idea of how the volume changes of the chambers in each situation will help or hurt the WO's ability.

But I would not scale it for some of the same reasons as BassBoy mentioned.  Added to the fact that if the WO is a horn, horns do not work the same when scaled.  If it is indeed an "Impedance transformer" or "Rubber throat"  basically a wideband port, changeing it by scaling will mess with it even more than adding 2 inches.  SO I would select the lesser of two evils.
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Gex
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Re: wo for 12s a lil help please.
Reply #13 - 06/11/06 at 16:23:39
 
Just Add 2" inches and your model will tell you if you need to move the baffle a little.
Do not move it back towards the sealed chamber.

IMHO
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« Last Edit: 06/11/06 at 16:28:49 by gexter »  
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60ndown
Ex Member



Re: wo for 12s a lil help please.
Reply #14 - 06/11/06 at 16:45:10
 
i have /use/ understand no software, winamp boxbuild etc.but it seems your all saying not to scale it? but just to add 2 inches in height and angle the baffle? can you explain in simple terms what effect scaleing it by 1.2 might have? to me it seems the shape and layout of the horn / throat is almost identical , just a little bigger? cant see how that will effect / change performace that much, but if you can shed some light on the issue for me id appreciate it.
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