Recommended 18 inch subs

ChaosWarlord26 · Post by **ChaosWarlord26** » Fri Dec 18, 2009 5:33 am

2 15's have 353.25 inches of cone area and 1 18 has 254.34 inches of cone area. More cone area is not always better.

Post by **stipud** » Fri Dec 18, 2009 7:33 am

I say if you're going to go big... go big! You need something that will wow people as much as your car does.

Post by **Eric D** » Fri Dec 18, 2009 7:49 am

This is the only 18" which I have ever been impressed by...

denim · Post by **denim** » Sat Dec 19, 2009 3:40 pm

kg1961 wrote:i would say 2 15"sub have more area 30" than 1 18" but that just me

Umm...

2 - 15" drivers: 353.25 sq. inches
1 - 18" driver: 254.34 sq. inches

Post by **kg1961** » Sat Dec 19, 2009 3:56 pm

denim wrote:
kg1961 wrote:i would say 2 15"sub have more area 30" than 1 18" but that just me
Umm...

2 - 15" drivers: 353.25 sq. inches
1 - 18" driver: 254.34 sq. inches

I was refering to to 15" sub will have more sq inches. sorry did do the math like you guys
I am not a fan of 18" but i also have never had a ton of cash for some of those monster subs
i am looking forward to my focal 15 as I'm told it sounds great

brenzbmr@sb · Post by **brenzbmr@sb** » Sun Dec 20, 2009 1:54 pm

hey doc, clean install, wanst a big fan of those amps but wanst that the last series rockford did an 18 inch sub. well untill they did those team rockford spl subs but i think those were made only for one guy and only four where made

KUB3 · Post by **KUB3** » Sun Dec 20, 2009 3:10 pm

Just a side note while were talking about large subs...

I just wonder whether these large subs might actually sound rather good in some situations. Usually it's just the SPL'ers who use the big drivers, typically in ported boxes. But there is also the option of sealed or even IB.

For a given 'normal' volume one might use for SQ listening, a large cone area will mean very small sub excursions. So the driver should be more inside it's linear range and have less distortion, when compare to a small cone having to move in and out a huge amount for the same volume. I have seen a build thread where a bass guitar musician made a sealed cabinet for a 21" PD driver for his home hifi. Apparently it was totally effortless, unforced and natural.

Also have any of you tried IB? I plan on using a couple of Celestion AD15 like this and give it a try. People I've talked to with experience say it's the most natural and linear sounding method around

Post by **ttocs** » Sun Dec 20, 2009 4:12 pm

IB - unless you know what you are doing and have the right equipment there is no better way to make a pair of 15s sound like a single 12......

KUB3 · Post by **KUB3** » Mon Dec 21, 2009 1:28 am

Well from what I have read everywhere that is always going to be the case. There is always a trade off. Generally it will be half the volume IB compared to sealed, for the same drivers. That is exactly why I intend to use two. Because I only want the output that one sealed would provide. This is for SQ, not SPL. If I were to use a sealed box I would only instal one 15. But IB also means no huge heavy birch ply cabinet and an empty trunk

ps

And no, I don't know what I'm doing

But I will be seeking advice prior to even choosing the car, so I get the correct trunk volume.

Post by **kg1961** » Mon Dec 21, 2009 6:24 am

when i used my jl 10w4ib they sounded great 2 of them sounded just like 2 10w0 jl sealed. I really did find there was only the sound of one sub. I made the wood wall that took a long time and was the same weight as a box:(.
I just wanted more so i made the jump to my focal set up for everything
i will install it in the next 2-4months

KUB3 · Post by **KUB3** » Mon Dec 21, 2009 6:28 am

Interesting KG. I've just done a little more reading up too. It seems double or even quad walled baffles are recommended, so there goes any weight advantage! Also my particular subs may be totally wrong for IB anyway due to a higher Fs. Oh well

Post by **kg1961** » Mon Dec 21, 2009 6:33 am

my wall was 1" thick but it was tight clean and hit pretty low
i liked it! if i had 12" or 15" jl ib i would have left it.
my problem is the acura tl trunk is small and the back seats don't do down

so i am making a small shallow box 55l for my focal and mounting the amp to that than adding a fake wall to hide it all minus the plexi windows

with the kid on the way i need the room for a stroller

KUB3 · Post by **KUB3** » Mon Dec 21, 2009 7:13 am

Yep, same here. That is why my previous sub was tiny - a CDT ES08 in a crazy small sealed enclosure.

denim · Post by **denim** » Thu Dec 24, 2009 7:54 am

kg1961 wrote:
denim wrote:
kg1961 wrote:i would say 2 15"sub have more area 30" than 1 18" but that just me
Umm...

2 - 15" drivers: 353.25 sq. inches
1 - 18" driver: 254.34 sq. inches

I was refering to to 15" sub will have more sq inches. sorry did do the math like you guys
I am not a fan of 18" but i also have never had a ton of cash for some of those monster subs
i am looking forward to my focal 15 as I'm told it sounds great

I didn't do the math either. I just checked the ISACA chart.

Half-Fast · Post by **Half-Fast** » Tue Dec 29, 2009 2:31 pm

FI BTL , feed it lots of power.

Post by **joerg** » Wed Jan 06, 2010 2:42 pm

http://cgi.ebay.de/Focal-46KX5-Subwoofe ... 414be943d0

Post by **kg1961** » Wed Jan 06, 2010 2:49 pm

very nice if i didn't have mine....just kidding i have to stop.lol

Post by **joerg** » Tue Feb 16, 2010 11:56 am

Found something my nickel will have to deal with in the future!

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... K:MEWNX:IT

I´m glad i found one in europe. Shipping killed all the deals with US guys

Post by **kg1961** » Tue Feb 16, 2010 12:06 pm

very nice I would pay you to use that box

lol just kidding

Post by **joerg** » Tue Feb 16, 2010 12:18 pm

kg1961 wrote:very nice I would pay you to use that box lol just kidding

The box stays with the seller!

To expensive to ship! And i´ve got no E-Class Mercedes to fit it anyways!

Post by **kg1961** » Tue Feb 16, 2010 12:48 pm

i would have a hard time putting that box in a rice rocket
man is it loud looking
good deal hope you like it

NewOldStock · Post by **NewOldStock** » Tue Feb 16, 2010 2:48 pm

oldskoolmseriesfan wrote:You liked the sound of your wife.....IN A BOX?! Thats a horrible thing to say.... mind you some of them would sound better in a box with a muzzle on too
On a seriouse note has anyone used the oldskool M&M Godfathers? Someone back in the day had 2 18's running off the largest 2 channel Rodek(early 90's when Rodek kicked ass) and the fucken pounded, and where very clean too.

I used 2 M&M 15's back in the day... replaced them with 4 Orion XTR's - so I dont have a clear comparison but I LOVED those M&M's. They are my biggest car audio regret.

they were awesome and if I could find some NIB I would have a hell of a time passing them up.

NewOldStock · Post by **NewOldStock** » Tue Feb 16, 2010 3:13 pm

ChaosWarlord26 wrote:2 15's have 353.25 inches of cone area and 1 18 has 254.34 inches of cone area. More cone area is not always better.

ChaosWarlord26 is right

Bigger subs are more efficient as a general rule - however, for a good IB sub you really need to look at the Le (inductance) of the sub, the cone area and its xmax.

for good IB, you need as low an inductance, maximum cone area and as much XMAX as possible. Take the Acoustic Elegance (Highly regarded as THE BEST IB sub available)
http://www.aespeakers.com/drivers.php?driver_id=8

Xmax of 18.5mm
and an Le (inductance) of a CRAZY LOW .33mH - lower the better.

Take a look at the Dayton HO 10 (also highly regarded as a real SQ sub) and it has a low Le of 1.9mH.

The Fosgate T215D4 on the other hand has a high Le of 5.5mH - more like an SPL sub than a SQ sub

The Focal Utopia has an Le of 2.05mH ...

my point is - you need something to move lots of air (15", 18" or multiple 10/12's) and it needs to be accurate and exceptionally responsive - otherwise it will just be woofing air without producing accurate sound.

So, in your search for an IB sub IMO AE would be as close to perfect as you can find.

Post by **ttocs** » Tue Feb 16, 2010 3:19 pm

oh man here comes the stroker can or worms again.

Are you keeping it in that box or what size are you planning?

oldskoolmseriesfan · Post by **oldskoolmseriesfan** » Tue Feb 16, 2010 3:27 pm

c'mon ttocs he said the box stays with the seller.....(so he can stroke it when it gets home

) you opened the can so there it is

Recommended 18 inch subs

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