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Discussion Starter · #1 · (Edited)
Ok, I am going to be testing a pair of the B&C 21sw152 out for the "Lights Out" theater. I haven't decided that they'll be the final winner of course, but I'm trying make my choice by experimenting with everything possible. Based on my taste so far in my subwoofer experience, I'm thinking the design of the 21SW might lend itself best to my purposes.
Quick breakdown to give some backround to those who may not know the history of my project. I've had the Dayton 18s and Si HT18s both now, and they are great values, but I'm looking to step up, mainly becuase building 32 single or 16 D/O enclosures will be a PITA :D. I've gotten experience with DTS10, Orbit shifters, subms, lms ultra, etc. I've had the 8 SI24s, though not all in use. We demo'd one at Beast's last year, and I did get two up and running at home to play with. They are output monsters and 1 to 1(or 1 to 2 or 3) slay just about anything I've seen. My biggest complaint is that they don't seem to have the midbass snap that I like, that slap you in the chest type feeling. They can shake your kidney stones loose though :D. My mains may do just fine crossing down at 60hz and make this a non issue, but I don't really want to roll the dice on that. Much easier to buy two drivers and see if they can dig deep enough for me. I am basically trying to get these 21Sw's to kill the midbass and extend as much as possible with authority...by design, they will pretty much kill the midbass no matter what, I think. I did look at the B&C 21ipal as well, due to higher xmax and ability to probably dig a bit deeper, a bit harder. A couple of memebers who have experience were nice enough to impart some knowledge...the concensous seems to be that they offer a 2-3db advantage. I'm all for every db, but I can add two and a half 21sw for every ipal so it makes sense to stick with trying these.
Here are my initial thoughts....no win on the office computer so I won't be able to model until later, but shooting from the hip here. I am going to build two enclosures to start. #1 will be sealed in the neighborhood of 5ft3 net. #2 I'm thinking of really large, very low tune...between 25-30cubes tuned to 12 or 12hz seems like it would work well...again I have to model it still, but if it does, it should have crazy output down to 10 or 12hz, usable for a few hz below that and just other wordly output from the mid teens up. My thoughts are that if we can make option #2 work out right, it will give me just enough ulf to feel the room shake and the chairs bounce, while delivering the cleanest and most pleasant midbass assualt a guy could ask for :D. Big thanks to Luke for agreeing to sell me a pair of these to get the experiment going!
 

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I’m very interested in this test. I too am starting to feel like I would prefer to have the extreme low-mid frequency capability of a pro woofer and give up some of the ULF. I’m more into music than movies so 20hz and below is a waste for my music. That 21 is not for me, but the B&C 18TBW100-4 looks like it could be a similar type of driver in an 18.
 

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Discussion Starter · #6 ·
I’m very interested in this test. I too am starting to feel like I would prefer to have the extreme low-mid frequency capability of a pro woofer and give up some of the ULF. I’m more into music than movies so 20hz and below is a waste for my music. That 21 is not for me, but the B&C 18TBW100-4 looks like it could be a similar type of driver in an 18.
Looking for our own fit takes us in lots of directions before we get there I guess. My situation is a bit different...I am way more movies, but I still think something like this can do enough ulf to create the effect, when used in enough mutliples, but give those of us looking for that pro type woofer sound and extension of long throw drivers a good solution. I could be all wrong, but that's why I want try it..to know for sure. My position would be that most of even the movie content, with a low teens tune, would be in the power band and create a perfectly acceptable ulf experience. You may tune higher to go smaller on the 18s, especially if looking above 20hz I'd think. I've seen some with mid 20s tunes that have disgusting output.
 

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You can enter your own port size in winisd. There are a few default options but you can just type yours over the defaults. On mine I have to hit tab or enter/return to get the exact value to stick.
 

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So I have two issues...1. I can't figure out how the heck to post my winisd graphs for folks to look at. 2. It seems like either win is limited with modeling the details of ported (not many vent size options) or I'm doing something wrong.
Print screen, then crop in paint. Upload an attachment then put the attachment link into the add an image box above.




If you click on the circle in the vent options it will change to square for a custom slot port like seen below

 

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Change the tune to 30hz and not many can touch it outside of a horn.

What if you do two of these tuned to 35hz and an SI24 for the low stuff? Three drivers and ridiculous spl. The low stuff will never have that "snap" anyways. And you could put the 24 anywhere without localization.
 

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your kinda defeating the purpose of the woofer by tuning it so low
Agreed. An identical performance can be had from the Ht18 for a quarter of the price.

Not sure I agree. Ricci's test shows the woofer wont go past 21mm no matter how much power is applied, so basically the low end is excursion limited but the top end is power limited. Models may show the driver exploding down low but it wont really (would still use a HPF) while still hitting 125 db up top.
 
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