IXL 18.2.2 in sealed boxes - 1 driver or two? - Home Theater Forum and Systems - HomeTheaterShack.com

Reply
 
Thread Tools
post #1 of 19 Old 06-13-10, 04:52 AM Thread Starter
Shackster
Mat
 
Join Date: Apr 2009
Posts: 7
IXL 18.2.2 in sealed boxes - 1 driver or two?

Hi everyone, thanks for all your posts on this forum - what a great resource.

I'm building a house and planning on an IB sub using 4 x IXL 18.2.2's. Yes, I know this is not the IB forum. Stay with me please!

While the house is being designed and built (12 months still) I want to put the drivers in simple boxes so I can play with them and the amp, etc.

I am building the (2) boxes already. For simplicity and WAF they are about 170l, sealed.

I'll be driving them with an EP4000 and EQ with a FBQ2496.

So, with boxes about this size, an EP4000 and four drivers to play with, can I use two drivers per box or will this be worse than a single driver per box?

I'm happy to cope with the complexity of the 2/box option if it will be a better result. Usage will be 80% HT, 20% music.

Modelling in WinISD seems to suggest it will be better with two per box, although I'm not sure how much amp power to use in each model...

Appreciate any advice please?
mrel is offline  
Sponsored Links
Advertisement
 
post #2 of 19 Old 06-13-10, 05:41 AM
Elite Shackster
 
Moonfly's Avatar
 
Join Date: Aug 2008
Posts: 7,142
Re: IXL 18.2.2 in sealed boxes - 1 driver or two?

Hi Mat, welcome to HTS.

I'm a big fan of sealed subs, but Ive pretty much come to the conclusion that to really do a sealed design justice you need to use multiple drivers. 2 drivers are excellent, and if you have more there is nothing wrong with making multiple driver designs etc etc.

I would build 2 dual driver boxes, this will give the best balance of having powerful subs while affording you the options to better integrate them into your system using eq, which I see your already setup to take advantage of. I assume you have REW and an SPL meter?

When modelling, a dual driver sub will require double the cabinet volume of a single driver version, and because your using 2 drivers, the subwoofers power handling also doubles (800 watts per driver max, so 1600 total). Sealed subs are power hungry beasts, and the power is needed to eq them properly, especially at the low end, so more power is good. Using multiple drivers simply means the available power is shared across the drivers. When you model your subs though, be sure to pay attention to the Qtc and adjust your cab size to suit the system Q your prefer. Typically, the middle ground (safest option if you dont know what your doing) is to go for .707. Higher will increase upper bass punch, but could lead to an overly boomy sound depending on your tastes. Lower will lead to a cleaner lower sound, which you might find robs some musicality, but your mainly HT focus will probably suit this more. FWIW, your IB will have a very low system Q close to the Qts value of your drivers, so to get more of an idea of how that will sound you could try a Qtc of .505. Larger cabinets will lower the system Q, and especially seeing as these are a temporary option, you could experiment a little by building larger cabs, and displacing some of the volume to alter the Qtc and learning from how system Q alters the sound character of a sealed sub.

Hope that ramble helps

Enjoy the forums
Moonfly is offline  
post #3 of 19 Old 06-13-10, 06:25 AM Thread Starter
Shackster
Mat
 
Join Date: Apr 2009
Posts: 7
Re: IXL 18.2.2 in sealed boxes - 1 driver or two?

Hey Moonfly, thanks for the quick and helpful response. Chalk up one vote for two drivers per cabinet, thanks!

Regarding Qtc, I'm a bit of a noob - how do I work that out? The manufacturer recommends 130l for a sealed cabinet. My boxes will be about 170l because this makes the box
(a) big enough to line up with the entertainment unit next to it
(b) big enough to fit two drivers in
(c) as big as I can get through the WAF.

EDIT - I think (if I did it right) that Qtc in a 170litre box (6 cu ft) is 0.56 - but this is for one driver, right? How does using two affect this?

If 170l turns out to be too big, I figured I can always displace some volume. I modelled this box in WinISD and it looks 130 or 170litres makes little difference - but again, I'm a noob and could be doing it completely wrong.

My other concern - I'm planning on only one EP4000 to drive both cabinets, will this drive 4 drivers across two cabinets OK or would I be better sticking with two drivers, two cabinets?

Thanks to all who are reading, and look forward to any help!

Last edited by mrel; 06-13-10 at 06:31 AM.
mrel is offline  
 
post #4 of 19 Old 06-13-10, 06:33 AM
Elite Shackster
 
Moonfly's Avatar
 
Join Date: Aug 2008
Posts: 7,142
Re: IXL 18.2.2 in sealed boxes - 1 driver or two?

The 130 litre recommendation is probably based on a Qtc of around .7, so for 2 driver you would need 260 litres to maintain the same system Q (Qtc value). If you look in the box tab of your model in WinISD, you will see the Qtc value at the bottom, and you can monitor how that changes when cabinet volume is altered. From the sounds of thing, 2 drivers in a 170litre cabinet will lead to quite a high System Q, which is going to make these subs very punchy, and probably insane chest pounders. The low end grunt will be there, but not as prominent and somewhat overshadowed by the upper bass power. You can help off set an undersized cabinet a little bit by using poly fibre fill stuffing, as this has the effect of making the driver(s) act like they are in a cabinet thats larger than it is. There is an article here on that:

http://www.nousaine.com/pdfs/Box%20Stuffing.pdf

The EP4000 is 2 ohm stable, so it can run both subs with dual drivers in each, but I would keep the stock fan in it for this purpose as its the heaviest load the amp can handle, which translates into it producing more heat. Its not an issue if enough air is moving over the heat sync to remove it and keep the amp cool. The up side is that the EP4000 will put out more wattage when running 2ohms, which will suit your subs better.
Moonfly is offline  
post #5 of 19 Old 06-13-10, 07:02 AM
Elite Shackster
 
Mike P.'s Avatar
Mike
 
Join Date: Apr 2007
Location: Chitek Lake, Sask.
Posts: 19,397
Re: IXL 18.2.2 in sealed boxes - 1 driver or two?

Quote:
The 130 litre recommendation is probably based on a Qtc of around .7,
130 liters gives a Q of .66, 105 liters gives a Q of .7.




We're all in this together!


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

Mike P. is offline  
post #6 of 19 Old 06-13-10, 08:56 AM Thread Starter
Shackster
Mat
 
Join Date: Apr 2009
Posts: 7
Re: IXL 18.2.2 in sealed boxes - 1 driver or two?

Wow, thanks guys so much for your help already. I didn't expect to get so many answers so quickly.

Of course Qtc is in WinISD, I thought it would be. I feel like an idiot. I didn't look hard enough.

Modelling with 2 drivers gives a Qtc of 0.726. That's not too far away from the ideal you mentioned of 0.707, is it? Makes me think the box size is still OK for two drivers perhaps? But then, 1 driver per box is a Q of 0.584 - good for real low bass. Hmmm.

Your comments about the load on the amp are great, and makes me stop and think. I can't live with a loud amp, either now or in the final IB setup - I HAVE to do the fan mod, I assume. Given that this will be the same load as in the IB, would I be best to get a second EP4000 maybe? At $570 AUD per amp it's not a big deal (compared to $1300 worth of drivers!). Obviously not ideal but a small price to pay for oodles of power and no risk of overheating etc. I'll have to do more research about guys running 4xIXL 18s off an EP4000. Anyone here doing that?

The sensible option would be one cabinet, two drivers, one EP4000.

Of course that's not going to happen!

Thanks again, Dan & Mike for your speedy answers. Any and all help appreciated.

Mat
mrel is offline  
post #7 of 19 Old 06-13-10, 09:03 AM
Elite Shackster
 
Mike P.'s Avatar
Mike
 
Join Date: Apr 2007
Location: Chitek Lake, Sask.
Posts: 19,397
Re: IXL 18.2.2 in sealed boxes - 1 driver or two?

Quote:
would I be best to get a second EP4000 maybe?
Yes, 4 subs on one amp is asking too much. I suggest you consider a second amp.






We're all in this together!


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

Mike P. is offline  
post #8 of 19 Old 06-13-10, 10:54 AM
Elite Shackster
 
Moonfly's Avatar
 
Join Date: Aug 2008
Posts: 7,142
Re: IXL 18.2.2 in sealed boxes - 1 driver or two?

I run my dual driver sub from an EP4000, and run it from one channel. My amp never gets hot so it is possible to run your subs from one amp. Could you put the EP in another room, thats what I did so I could keep the original fan in. I also keep the clip limiter on just for peace of mind, and may spare channel runs a bass shaker. My amp never even gets warm. If your going to mod the fans though, I do think a second amp will be a good idea, but when you get the IB up and running, you wont need as much power and series wiring your drivers will lower the load and one amp will probably fine at that point.

I think the 130 litre subs QTC is a good one, and thats what Ive made my subs Qtc at (.675 for mine), and I think it sound fantastic. It also suggests the driver have good upper bass sound naturally, which again is a good thing, and makes them a good choice for an IB too IMO. I think a Qtc of .726 will be leaning towards the boomy side, but you can easily try it and see what you think, and taste is personal.
Moonfly is offline  
post #9 of 19 Old 06-13-10, 05:39 PM Thread Starter
Shackster
Mat
 
Join Date: Apr 2009
Posts: 7
Re: IXL 18.2.2 in sealed boxes - 1 driver or two?

OK, great, thanks. I didn't realise you could series-wire the drivers in an IB (hadn't read that far ahead!).

My plan will be two cabinets, one driver each (for a Qtc around 0.58) and one EP4000. This should give me a sound closer to an IB (which I've never heard so I'm keen to keep the sound more similar) and a suitable load for the amp.

I can always displace some volume inside the boxes then to play with the Qtc.

Guys, I can't thank you again. Off to the workshop!
mrel is offline  
post #10 of 19 Old 06-13-10, 05:42 PM
Elite Shackster
 
Moonfly's Avatar
 
Join Date: Aug 2008
Posts: 7,142
Re: IXL 18.2.2 in sealed boxes - 1 driver or two?

Sounds like a good plan, just remember though that it takes less power to move the driver as you increase cab size. Chances are you could bottom the drivers if you push too hard (although Ive not modelled it), which isnt an issue, but you should be aware of it for peace of mind. You can monitor this in WinISD as well
Moonfly is offline  
Reply

Bookmarks

Tags
18.2.2 , boxes , driver , sealed , two?

Quick Reply
Message:
Options

Register Now




PLEASE COMPLETE ALL REQUIRED FIELDS BELOW... THANKS!

REQUIRED FIELDS ON THIS PAGE
YOU MUST COMPLETE ALL OF THESE

Username
Password
Confirm Password
Email Address
Confirm Email Address
Random Question
Random Question #2




User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
PLEASE READ BELOW PRIOR TO ENTERING AN EMAIL ADDRESS!

ATTENTION!

YOU MUST ACTIVATE YOUR ACCOUNT!

Activation requires you reply to an email we will send you after you register... if you do not reply to this email, you will not be able to view certain areas of the forum or certain images... nor will you be able download software.

AN INVALID EMAIL ADDRESS WILL CAUSE YOUR ACCOUNT TO BE DELETED!

See our banned email list here: Banned Email List

We DO NOT respond to spamcop, boxtrapper and spamblocker emails... please add @hometheatershack DOT com to your whitelist prior to registering or you will get nowhere on your registration.


Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML is not allowed!
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


For the best viewing experience please update your browser to Google Chrome