So I have been giving some though to this from a theory stand point and just wanted to see what you all thought.
Obviously as most of you know I'm not new to this by any stretch but every box that I have built for myself has been ported and any sealed boxes I did were just for the customers at circuit city and were with crappy subs for the most part. So now I'm thinking of venturing into new waters with the idea of stepping into new waters of SQL using large, high powered, sealed subs.
Here's my though logic and you all could help me Build upon it. I was looking at the Sundown Z and NS line when I came to this conclusion and I have noticed it would not work the same way for other subs but... The general rule is ported>sealed by 3db, also double cone area = 3db increase. So with that said it would stand to reason that a sealed 18 would be louder than a ported 12? No? The reason I am comparing those is sundown recommends around 2 cu ft + port for a 12 and only 3 cu ft sealed for an 18. Effectively the same box size with the 18 being just slightly larger. Now as far as cone area, the 18 is a little more than double the cone area of a 12.
Am I missing something? I tried to graph both the NS and the Z 18's in winisd but they both look to sharply roll off everything below 80hz? Something to the tune of an 8db loss from 80hz to 30...
That curve sounds reasonable. Cabin gain will flatten out the response a lot. A sealed 18 would likely have less pure output, but will be louder across the spectrum due to the sealed response. A ported 12 will have the bloated low end with port gain to help it out. I was also going to run an 18 sealed but went with 2 15s instead. There's nothing like the sound of sealed, and with that cone area it'll be pretty loud to boot
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That curve sounds reasonable. Cabin gain will flatten out the response a lot. A sealed 18 would likely have less pure output, but will be louder across the spectrum due to the sealed response. A ported 12 will have the bloated low end with port gain to help it out. I was also going to run an 18 sealed but went with 2 15s instead. There's nothing like the sound of sealed, and with that cone area it'll be pretty loud to boot
Here are the graphs I made. Red is 2 12" NS ported, Green is 2 18" Z sealed, Yellow is 2 18" NS sealed.
So total output loss, how much would you guess? at what frequencies? Sorry, short of some kicker comps and P2's etc I've never put anything in sealed. I'm thinking 6k to a pair of 18" NS sealed instead of 2 12" ns ported
i think the ported enclosure will have peak output by a little bit from the hump down low, but the 18" nightshades are going to do very well, that response should really flatten out and be pretty loud
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i think the ported enclosure will have peak output by a little bit from the hump down low, but the 18" nightshades are going to do very well, that response should really flatten out and be pretty loud
Hmm... ya I still dont know. Guess I'm just scared to venture into new waters lol. How do sealed subs perform when they have gobs of Power thrown at them? I would think they have some cooling issues due to lack of air flow.
Maybe we could just take a vote. Like everyone pick one and a one liner of why.
Or even better yet, maybe I'm just looking at the wrongs subs for this. The only reason I started to consider it was I noticed Sundown recommended 3 cubs sealed per 18. Thats about what I have to work with. Maybe 3.5 on the high end but I'd be happier sticking to 3 each and maybe filling it with some poly.
So any sub recommendations would be great to. Goal is SQL, love the lows from about 25-35hz. Power is 6k nominal.
zcons would do well in it as well, might even have a little more sq in the mix. the nightshades are a pretty good option, and they get real nasty in 4th orders if you plan on going to the big leagues
thermally and mechanically, either sub should do fine in a sealed application. both subs are very underrated in their specs, and as long as the signal is kept clean they will have no issue cooling given that power.
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zcons would do well in it as well, might even have a little more sq in the mix. the nightshades are a pretty good option, and they get real nasty in 4th orders if you plan on going to the big leagues
thermally and mechanically, either sub should do fine in a sealed application. both subs are very underrated in their specs, and as long as the signal is kept clean they will have no issue cooling given that power.
Based on the T/s that sub doesn't look like it would fair well in a sealed enclosure.
Keep in mind ported rolls off at 24db/oct and sealed at 12db/oct. Where they start rolling off depends on the box size and in the case of ported the tuning of the port.
If an 18 is in a box much smaller than it's VAS, it might very well start rolling off much above it's FS. But the sensitivity before the rolloff will be fairly high. So the ported box might have higher peak output, but the sealed box will out do it on a wider range of notes.
Add cabin gain (check my winISD tutorial thread) and you can see where sealed really shines. The 12db/oct roll off gets filled in and you get a great frequency response.
But also lets consider transient response. The large peak in the ported box (cause by using a box much larger than the subs VAS) also causes a lot of energy to be stored. The box more or less rings at this freq. So your transient response gets muddied up. You end up having very high group delay. Lots of peak output, but not necessarily the cleanest sounding box. Sealed on the otherhand has great transient response in most modest boxes. Aim for a box roughly the same size as VAS. It'll often get you a Q of .707. Which gives you a great transient response (critically damped )
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Car: 2009 Audi A4 Avant Quattro
Sub amp: Hifonics ZXX-3200.1D
Subwoofers: 4 SA8V.2 @ 2 Ohms
Enclosure: 2 cu ft ported, tuned to 33Hz
I would never put a ns v2 12 in 2 cubes ported on that much power. more like 1.25. a ns v2 18 is perfect in 4 cubes ported with 75 sq inches of port. havent done much with them sealed though so i wont recommend anything on that but i would assume they would like tiny sealed enclosures
Keep in mind ported rolls off at 24db/oct and sealed at 12db/oct. Where they start rolling off depends on the box size and in the case of ported the tuning of the port.
If an 18 is in a box much smaller than it's VAS, it might very well start rolling off much above it's FS. But the sensitivity before the rolloff will be fairly high. So the ported box might have higher peak output, but the sealed box will out do it on a wider range of notes.
Add cabin gain (check my winISD tutorial thread) and you can see where sealed really shines. The 12db/oct roll off gets filled in and you get a great frequency response.
But also lets consider transient response. The large peak in the ported box (cause by using a box much larger than the subs VAS) also causes a lot of energy to be stored. The box more or less rings at this freq. So your transient response gets muddied up. You end up having very high group delay. Lots of peak output, but not necessarily the cleanest sounding box. Sealed on the otherhand has great transient response in most modest boxes. Aim for a box roughly the same size as VAS. It'll often get you a Q of .707. Which gives you a great transient response (critically damped )
Just want to clear something up. Bold section ^^^^
Are you talking about sealed or ported?
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Keep in mind ported rolls off at 24db/oct and sealed at 12db/oct. Where they start rolling off depends on the box size and in the case of ported the tuning of the port.
If an 18 is in a box much smaller than it's VAS, it might very well start rolling off much above it's FS. But the sensitivity before the rolloff will be fairly high. So the ported box might have higher peak output, but the sealed box will out do it on a wider range of notes.
Add cabin gain (check my winISD tutorial thread) and you can see where sealed really shines. The 12db/oct roll off gets filled in and you get a great frequency response.
But also lets consider transient response. The large peak in the ported box (cause by using a box much larger than the subs VAS) also causes a lot of energy to be stored. The box more or less rings at this freq. So your transient response gets muddied up. You end up having very high group delay. Lots of peak output, but not necessarily the cleanest sounding box. Sealed on the otherhand has great transient response in most modest boxes. Aim for a box roughly the same size as VAS. It'll often get you a Q of .707. Which gives you a great transient response (critically damped )
Lol this is why you earned that signature. The vas of that sub is 3.27 cu ft so I can get in and around there with a total box size of 6.5. so that shouldn't be to much of a problem.
So sealed 18 will likely result a couple db loss in a narrow bandwidth but higher db in the outlining frequencies. For daily that seems like a fair compromise to me.
I did read that thread btw, as well as all the other ones similtar to my question that you posted in. Prior to posting my question I might add .
What did you mean by critically damped?
Also what's your thoughts on the drivers we have discussed and is there any others that you think I should give consideration to?
Thanks again for your help. Its always appreciated.
Quote:
Originally Posted by perfect_prefect
I would never put a ns v2 12 in 2 cubes ported on that much power. more like 1.25. a ns v2 18 is perfect in 4 cubes ported with 75 sq inches of port. havent done much with them sealed though so i wont recommend anything on that but i would assume they would like tiny sealed enclosures
Yes 2 would bee on the larger side for them and was likly going to put them in 1.5-1.75 each in reality but most 12's do well in 2 so I was kind of going off that. I looked at the 15's and I couldn't get them in the space properly so it really came down to a 12 ported vs 18 sealed argument.
A single 18 ported would fit in my space but wouldn't take the power I want to give them. I would think spl wise 2 sealed 18s would be similar to a ported 18 tuned for a reasonably flat response. Then the extra 2-3k of power would help the sealed get louder overall. Same logic as to why I originally was thinking 2 ported 12s on twice the power than the single ported 18.
critically damped is a type of oscillation control. if you consider the box and sub a system, a perfect damping system would be where nothing interferes with the cone movement. that is known as being critically damped. theres no excess oscillation, and nothing slowing the desired oscillation down.
p.s. he pretty much repeated what i said, but with larger words
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I personally have a pair of ns 12" in 3.5 with a 6" aero @ 35hz it was built to be ran on a pair of sax1200s. i cannot put over 2k to the pair on music without losing control of the cone. i would put a pair of ns v2 15" in 4 cubes ported and call it a day
critically damped is a type of oscillation control. if you consider the box and sub a system, a perfect damping system would be where nothing interferes with the cone movement. that is known as being critically damped. theres no excess oscillation, and nothing slowing the desired oscillation down.
p.s. he pretty much repeated what i said, but with larger words
Pictures are nice and easy to understand... Thanks
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p.s. he pretty much repeated what i said, but with larger words
Thank you as well. I actually added rep for both of you for your help and I don't value you input any less I just like to get input from multiple smart individuals. Helps keep biased opinions in check.
Quote:
Originally Posted by perfect_prefect
I personally have a pair of ns 12" in 3.5 with a 6" aero @ 35hz it was built to be ran on a pair of sax1200s. i cannot put over 2k to the pair on music without losing control of the cone. i would put a pair of ns v2 15" in 4 cubes ported and call it a day
Personally I haven't owned the NS subs but something seems off there. You have the subs in 1.75 each tuned to 35hz and they can only take half their rated rms before losing control of the cone?
I wish I could the the 15's. In my car I can fire up or back. I tried up and sub up port back and didn't like either so I'm really stuck with doing sub and port back. Here is an image of actual size of the subs on the surface area I have. You can see the top is 2 18's with no port, the bottom is 2 12's with room for a port and the middle is 2 15's with no room for the port. The only way for me to do the port there is to make a slot which would require quite a bit more gross space.
what kind of car? ns v2 subs like really really small boxes. yes i smack triple joint on top plate on music with just over 2k clamped. i can burp them right close to tuning on 4k no issues but away from tuning they hate me
what kind of car? ns v2 subs like really really small boxes. yes i smack triple joint on top plate on music with just over 2k clamped. i can burp them right close to tuning on 4k no issues but away from tuning they hate me
Lol, I totally trust you. The 12's do look like they peak really bad so I guess I could see that. Its my 2011 xb. So in reality then the NS probably isn't the sub for me if I'm planning to port but sealed it may work better on that power because it will be less likely to unload. What's your thoughts on that sp4 or other subs. I don't know why the but idea of 2 sealed 18's sound kind of cool but i gotta keep them in 6-7 cu ft which isn't the easiest thing to do.
3k nominal will probably clamp under 2k after impedance rise
Yep thats why I thought it would be important to point that out. Each sub will probably see 2k, maybe up to 2.5 if I get really lucky and the box ends up being super effiecient.
Oh and they would likely be NS3 subs. Jacob has the baskets in now so they shouldn't be much longer. He also stated that the enclosures would stay the same for them so I'm just kind of using the NS2 as a close reference to plan off of.
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