Can the Fi IB18" be ported?

**cdy2179** · **10-08-09, 05:00 PM**

I've built several DIY subs in the past 12 years or so. My last one was an IB manifold in my theater room. I'm kinda missing my old sonotube sube I had before. My current dual Fi IB18 system has been calibrated with BFD and has more output than I need, however it just doesn't sound quite as clean as it should even though it's response after calibration is good.

So my question is can I use the IB18s in a ported sonotube config? I know they are built just for IB but i'm not sure exactly what changes were put inot them that Fi's other drivers don't or do have. I tried modeling it in winISD and it came up with a ridiculously large box at 1839 liters, but I can get it to 800 liters and still keep a decent plot falling 3db at 15hz

Has anyone else tried this?

**dyohn** · **10-08-09, 05:36 PM**

The only thing different about a driver designed for IB alignment and any other is it will have a higher Qts. If you've modeled it then you have seen the predicted output. If you can make it work, go for it. Remember that your in-room response will be different than what WinISD predicts.

**Mike P.** · **10-08-09, 06:39 PM**

Are they IB18's or IB3 18's?

**Mike P.** · **10-08-09, 06:50 PM**

This is the IB3 S2, all models with 600 watts input.

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**Ryan Anderson** · **10-09-09, 02:40 AM**

anything CAN be done. it's not optimal. basically the softparts, specifically the voice coil, are just about the same..basket is the same. the magnets are smaller, the top/bottom plate may be smaller, and the pole piece has less steel as well... less steel and less magnet for a smaller overall motor.

I currently have an IB3 18" in 21 cubes tuned to 15Hz. PM me for vids. It sounds amazing, it works great, but it was a temporary build. I will be going 21" Maelstrom-X later.

If you're looking at Fi, the Q is better suited. yes, it's more money. If you really want to get by and you have lots of room, you could trade off and sacrifice... I loved mine... but look at Mike's plot... looks nasty, dont it?

BTW... having finally seen an LLT "speaker pron" vid, I realized something may not have gone right with mine... I still had large excursion around tuning, I thought it was normal because I was tuned so low... but having seen sub_junkie's vid, I don't know if it is his or mine not working properly. Granted I have 3X his airspace (as I have an under motored IB sub) but I should still see less excursion around tuning then I did.

**cdy2179** · **10-09-09, 04:02 PM**

Quote:

Mike P. wrote:

Are they IB18's or IB3 18's?

They are only about a year old but I'm pretty sure they aren't the IB3s thy're the original IB 18s.

**cdy2179** · **10-09-09, 04:08 PM**

Quote:

Ryan Anderson wrote:

anything CAN be done. it's not optimal. basically the softparts, specifically the voice coil, are just about the same..basket is the same. the magnets are smaller, the top/bottom plate may be smaller, and the pole piece has less steel as well... less steel and less magnet for a smaller overall motor.

I currently have an IB3 18" in 21 cubes tuned to 15Hz. PM me for vids. It sounds amazing, it works great, but it was a temporary build. I will be going 21" Maelstrom-X later.

If you're looking at Fi, the Q is better suited. yes, it's more money. If you really want to get by and you have lots of room, you could trade off and sacrifice... I loved mine... but look at Mike's plot... looks nasty, dont it?

BTW... having finally seen an LLT "speaker pron" vid, I realized something may not have gone right with mine... I still had large excursion around tuning, I thought it was normal because I was tuned so low... but having seen sub_junkie's vid, I don't know if it is his or mine not working properly. Granted I have 3X his airspace (as I have an under motored IB sub) but I should still see less excursion around tuning then I did.

I'm glad to see it's been done... I'm just wondering how not using the Fi q series for instance or other popular subs vs. one made for IB will affect the performance, I really want a system I can be satisfied with and call that part of my ystem "DONE". I'm assuming even the IB 18 in a sontube should have way ore output than the IB config... I want somthing Jawdropping when I want it to be, yet very clean and clear.

**Ryan Anderson** · **10-11-09, 10:10 AM**

Quote:

cdy2179 wrote:

I'm glad to see it's been done... I'm just wondering how not using the Fi q series for instance or other popular subs vs. one made for IB will affect the performance, I really want a system I can be satisfied with and call that part of my ystem "DONE". I'm assuming even the IB 18 in a sontube should have way ore output than the IB config... I want somthing Jawdropping when I want it to be, yet very clean and clear.

http://www.youtube.com/user/kryptoni...18/3jzenFwzkZk

Fi IB3 18" in 21 cubic feet, 8" port tuned to 15Hz. THE best clean low and loud system I have ever heard, better than some Ascendant Audio Avalanche setups even.

looks TERRIBLE... so if it sounded that good, I can't wait to hear the maelstrom-X build

**cdy2179** · **10-11-09, 11:48 AM**

I think I may go for it. My room has a column theme to it already so 2 big column like sonotubes should fit right in. They will however push my new Rocket rs850s out into the room a little more. I also have to make sure subs in the corners will be OK using REW.

**Mike P.** · **10-11-09, 01:28 PM**

What size and tuning are you considering?

**cdy2179** · **10-12-09, 01:26 PM**

I'm thinking about 32" sonotube 6' tall (I can cut the 12' stick in half) , 900 liters, tuned to 15 hz. I would rather use 24" but it would be way too tall to get a reasonable response curve.

**Ricci** · **10-12-09, 01:40 PM**

32" sono and 900 liters

That is absolutely HUGE...I'd advise using a different driver. With some drivers you could do 2 18" subs tuned to 15hz in that same 900L. The Fi Q18 is better suited to something like this. 6 or 700L would be more than plenty for those. IXL 18's would be fine in 400-450L each.

**cdy2179** · **10-12-09, 04:56 PM**

That is huge, i'd much rather use 24" sonotube... wanna buy some IB18s???

**weverb** · **10-12-09, 08:32 PM**

Quote:

cdy2179 wrote:

wanna buy some IB18s???

How much?

**Ryan Anderson** · **10-13-09, 01:52 AM**

Quote:

cdy2179 wrote:

That is huge, i'd much rather use 24" sonotube... wanna buy some IB18s???

it's crazy how so many are willing to sacrifice so much time, energy, money... so much planning, detailing, tweaking. so much for looks. cosmetics. But the one thing no one will give up is space.

**cdy2179** · **10-13-09, 08:39 AM**

Quote:

Ryan Anderson wrote:

it's crazy how so many are willing to sacrifice so much time, energy, money... so much planning, detailing, tweaking. so much for looks. cosmetics. But the one thing no one will give up is space.

I'll give up some space, just not half a room

.

**stidrvr** · **10-14-09, 12:17 PM**

Quote:

Ryan Anderson wrote:

http://www.youtube.com/user/kryptoni...18/3jzenFwzkZk

Fi IB3 18" in 21 cubic feet, 8" port tuned to 15Hz. THE best clean low and loud system I have ever heard, better than some Ascendant Audio Avalanche setups even.

looks TERRIBLE... so if it sounded that good, I can't wait to hear the maelstrom-X build

Whats the port length for that?

**Ryan Anderson** · **10-14-09, 04:11 PM**

Quote:

cdy2179 wrote:

I'll give up some space, just not half a room

.

hehehe gotta draw the line somewhere

Quote:

stidrvr wrote:

Whats the port length for that?

19.5", 7.75" diameter, 21 cubes after all displacement.... 15.42Hz tune. As of now, though, it's at 13.5" for a 17.5Hz tune

**stidrvr** · **10-14-09, 07:27 PM**

Quote:

Ryan Anderson wrote:

hehehe gotta draw the line somewhere

19.5", 7.75" diameter, 21 cubes after all displacement.... 15.42Hz tune. As of now, though, it's at 13.5" for a 17.5Hz tune

Lemme ask you this. Since it seems your the only one that has done this. I have four IB18's and am thinking of using you model with all four a 88x41.5x41.5 enclosure. Which I can do. Each will have it's own chamber.

What's your opinion on this?
My planned IB really can't happen anymore but this could. It will be powered by a QSC RMX-2450 so 600w per sub.
Posted via Mobile Device

**Ryan Anderson** · **10-14-09, 11:27 PM**

Quote:

stidrvr wrote:

Lemme ask you this. Since it seems your the only one that has done this. I have four IB18's and am thinking of using you model with all four a 88x41.5x41.5 enclosure. Which I can do. Each will have it's own chamber.

What's your opinion on this?
My planned IB really can't happen anymore but this could. It will be powered by a QSC RMX-2450 so 600w per sub.
Posted via Mobile Device

My very humble opinion: any subwoofer can be used in any situation if you want it to. To me, IMHO, 2 factors are the most important (most important obviosely means everything else still is too) Sd and Xmax. How much air you can move is what it comes down to. Sacrificing that much airspace helps "fix" 2 problems, power and sound. These drivers are designed to sound great in lots and lots of space with very little power. If you squeeze them in a little box, the FR curve suffers and too much power is needed.

I'll bet Mike will give you a plot pretty soon here. If not, I'll do one myself. I don't want to chance errors, and, I like his other suggestions he gives along with his plots... so I'll wait for him. But, he may very well try to talk you out of it. We will have to see!

**cdy2179** · **10-15-09, 09:46 AM**

I've plotted the Fi IB18 at several different sizes, they shine at a huge 1800 liters, not bad down to 800-900 liters, below that they really begin to fall off way too soon. They definatley like LLT boxes.

**Mike P.** · **10-15-09, 10:50 AM**

IB subs are designed for IB applications. Yes, you can put them in a really big ported box. 900 liters is 32 cu.ft., not something I would consider but that's just me. 20 cu. ft. tuned to 16.5 hz would produce the same output as a IXL-18 in 13 cu.ft. if you use a BFD to get rid of the hump in the response.

Using the same 20 cu.ft. box tuned to 16.5 hz and put a 18" Maelstrom -X in it. The results would be scary. 120db at 17 hz, plus room gain.

It all depends what you want to do. Keep the IB subs and plan for the future, or sell the IB's now and get some subs that better suited to smaller ported boxes.

**cdy2179** · **10-15-09, 12:06 PM**

Quote:

Mike P. wrote:

IB subs are designed for IB applications. Yes, you can put them in a really big ported box. 900 liters is 32 cu.ft., not something I would consider but that's just me. 20 cu. ft. tuned to 16.5 hz would produce the same output as a IXL-18 in 13 cu.ft. if you use a BFD to get rid of the hump in the response.

Using the same 20 cu.ft. box tuned to 16.5 hz and put a 18" Maelstrom -X in it. The results would be scary. 120db at 17 hz, plus room gain.

It all depends what you want to do. Keep the IB subs and plan for the future, or sell the IB's now and get some subs that better suited to smaller ported boxes.

I agree. I'm thinking I'll probably try and find a better spot for the IB and if that doesn't work i'll sell them and build some 24" sonotubes.

It's been a while since I've looked at anything other than IB, what are some of the best bang for your buck 15" and 18" subs at the moment. low fs with high Xmax and easy to drive of course.

**Mike P.** · **10-15-09, 01:06 PM**

Best bang for the buck at the moment is the CSS SDX15, $271 shipping included. Compared to the IXL-18, $265 shipping included, it has the same output. Both with 1000 watts input, the SDX15 is under Xmax while the IXL is slightly over. Both with a HPF at 15 hz. The SDX15 has an XBL motor for lower distortion.

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**Ryan Anderson** · **10-15-09, 10:22 PM**

Quote:

Mike P. wrote:

IB subs are designed for IB applications. Yes, you can put them in a really big ported box. 900 liters is 32 cu.ft., not something I would consider but that's just me. 20 cu. ft. tuned to 16.5 hz would produce the same output as a IXL-18 in 13 cu.ft. if you use a BFD to get rid of the hump in the response.

Using the same 20 cu.ft. box tuned to 16.5 hz and put a 18" Maelstrom -X in it. The results would be scary. 120db at 17 hz, plus room gain.

It all depends what you want to do. Keep the IB subs and plan for the future, or sell the IB's now and get some subs that better suited to smaller ported boxes.

IB3 18 $220
Maelstrom-X 18" $395

had I had $425 to get a Mael-X shipped, I'd have one right now...but I only had $240. This guy already has 4 of them. I bet he wishes he had MX's but he doesn't

IDK how much you could get for used IB3's... I'd sell mine, but it's customized

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