Bass Bins - Need Help

[Dean100]

Would like to build some bass bins this winter. These will be used with my Nat P's.

I am thinking that I would like to use 2 10's or 12's in each sealed bass bin. I will then plug the ports on my Nat P's and run them sealed. Also I have a sealed 15" Tumult sub that I will use for the low stuff. Will actively cross the bass bins using one of the Behringer units. I listen to music most of the time and only occasionaly do the home theater stuff.

At this point, I am looking for suggestions at what drivers to consider and what might be the approximate size cabinet volume to use for said drivers. Should I go with 2 drivers per bin or can I consider just using one driver? Cost is really not an issue, but probably don't want to spend more than $600 total for drivers.

[Jonasz]

I vote for these: http://www.madisound.com/catalog/pro...products_id=79

You can cross them at say 200hz and then let the big one take over under 50... :P

[Dean100]

Did a search here at HT Guide and read a bit about those Aura NS10's. They look like an excellent driver and I should be able to cross them fairly high, say 200hz - 250hz.

Now my questions are, two per bass bin or just one? Can I use these in a sealed alignment or should I port them?

Thanks for any advice!

[ThomasW]

Are you using a sub in addition to the bass bins?

[Dean100]

Thomas, yes as stated in my original post. I am using a 15" Tumult sealed sub for the low end.

Thanks for chiming in. I was hoping to get your thoughts on this as you seem to know as much as anyone about bass bins.

[ThomasW]

Thomas, yes as stated in my original post. I am using a 15" Tumult sealed sub for the low end.

Oops that's right....I have brain fade do to a fever/cold...

You could probably get by with one/side.

That said, those are incredibly good drivers and the sale pricing is a steal. So if the budget permits go with 4 and have a ton of headroom.

I'd run them sealed and use a dab of EQ to boost the low end as needed

[Dean100]

Ok. Think I will go with 2 of the Aura NS10's per side for a total of 4 and get them real soon while they are on sale.

Now, can anyone run a sim in Unibox and advise me what approximate box volume I should consider to use these in a sealed alignment. I have played around with Unibox a little but I really don't know what I am doing.

Thanks!

[---k---]

This is what I got for 2 of them in one box. I don't know what I'm doing either. Looks like it doesn't need much volume sealed, but also doesn't extend very deep. I guess that is why Thomas recommended using a bit of eq to boost the low end.

Less than 1 db difference between the 90L box and a 25L box until 60hz when you're rolling the sub in. I would build what looks right.

[PoorboyMike]

Thomas,

How high up can you run the NS10s? I want to do bass bins for either the Lineup D44/R44 or NatP/NeoCC. I'm leaning towards the Lineup series due to the fact that I have a pile of TB 1334's laying around. If I went that route, I'd like to cross the bass bins up towards 500hz.

Can the NS10s go that high?

I'm looking for hard hitting mid bass and high spl for concert DVD's in a 5.1 set up. Deep bass would be handled by an IB sub.

Sorry for the hijack, this thread just seemed appropriate to ask the question. ops:

[ThomasW]

The first cone mode is 1.5kHz...... see here

http://www.madisound.com/catalog/PDF/aurasound/NS10-513-4A.pdf

[Dean100]

I have placed the order today for the Aura NS 10's. This project will take awhile as my free time is somewhat limited right now. Next step will to be to determine the the size and shape that I want to go with.

Ryan,thanks for the Unibox sim. Thomas, thank you for your thoughts on this. :T

I will come back to this post later with further questions.

[Dean100]

The Aura NS 10's will arrive tomorrow, Trying to figure out the size for the bass bins. Am I correct that I don't have to worry too much about Qtc and that I can make these pretty much any size that I want to?

I can high pass my receiver (B&K AVR 305) as high as 200hz. Which I will run to the Nat P's. Will set the low pass on my receiver to external, then run pre outs to an external crossover (which Behringer crossover?).

From the Behringer to external amp - bass bins.

From Behringer to external amp - sub? Am I correct in thinking that I want to use the Behringer crossover and and not my sub out on the receiver?

Really looking forward to this project.

[augerpro]

I would use the receiver's bass management as you normally would, to separate the sub from the rest. Then use the CX2310 to separate the Aura woofer from the NatP's. Reason being the receiver should use a BW2 for the HP, which would be too shallow if you used it up past 200hz. But it will work well with Aura's 2nd order roll off on the low end. Ideally you would cross the sub to the Aura at the Aura's F3 in a Qtc=.7 sealed box (again a BW2 filter). Cascading the BW2 filters like this is equal to a LR4, which is what the receiver will apply to the sub's LP. Perfect match.

Now the CX2310 will apply LR4 to both the HP and LP, which means the response of the drivers in this area must be relatively flat to sum properly. Which they will be around 200hz. Again perfect match.

Although you will have BSC on the NatP's and not on the Aura...hmmm let me think about that.

[augerpro]

Looking at Ryan's sim I see the Qtc=.7 box has an F3 of 60hz and that seems to be a good crossover point for the sub. Still not sure about the BSC situation though. The lower you cross the less of a problem this is...I'll do a baffle sim and see how high you can cross without a big response ripple.

[Dean100]

As I am thinking this through. If I high pass my receiver at 200hz, then what is coming out of my pre outs is also high passed? If this is the case, then it doesn't look like it would work. As the signal going to the Behringer would be high passed.

It would be nice if I could use 2 channels of my receivers amplifier instead of having to buy 2 more channels of amplification.

Brandon -thanks for your reply!

[augerpro]

In my example I would set the receiver's HP and LP to 60hz. Run the LFE to the sub and run the main preouts to the CX2310, where it will further divide the frequencies at 200hz or whatever you settle on. I see what you are saying about needing more external amps. The problem here is that the slopes used by the CX2310 and the receiver are different, the CX2310 will use LR4 for both HP and LP, while the receiver should use BW2 for the HP and LR4 for the LP. The receiver is like this because it assumes that the mains will have a natural 2nd order roll off in the bass region to which it applies an additional 2nd order roll off for net roll off of 4th order-which will match the LR4 LP of the sub perfectly. For the CX2310 using it's LR4 filter, it expects that the driver responses are relatively flat, which wouldn't be the case with the Aura at bass frequencies.

To be honest I don't know how much of a problem it would be to swap it around like you want, but I do know that you would have a 2nd order roll off of the Nat's combining with the 4th order (actually a little less due to BF) of the Aura and you will likely end up with some phase cancellation which would kind of defeat the purpose for adding separate midbasses anyway. I'll think about this some more though, I'm pretty tired right now and not thinking too straight :Z

[Dean100]

Brandon, thanks for your input.

My receiver does allow for some different crossover slopes if this will help. The choices are:

High Pass - 6.0 dB or 12.0 dB slope
Low Pass - 6.0 dB or 12.0 dB or 24.0 dB slope