The Dave's Fi IB Quad 18" Build Thread

**Avus_M3** · **03-05-08, 04:11 PM**

Sorry for the absence. I was in Reno/Tahoe a week ago and I just got back from San Diego so have not had anytime for this project.

Updates will come

.

**Avus_M3** · **03-05-08, 04:16 PM**

Quote:

MatrixDweller wrote:

This infinite baffle stuff is taking this hobby to a whole new level.

What do your neighbours think when you crank things up?

How well do your other speakers keep up?

I don't think my neighbors will mind. I live on 1/3 of an acre that is lined with trees. I cranked my mains (0 db or -5 db IIRC) and walked outside in front of the house...barely barely audible. Inside it was blasting. As far as the mains keeping up read the sentence before. I have noticed recently a breaking up sound. From what I can tell it seems it's coming from the mid's suspension almost like the glue is coming undone?

Quote:

bonehead848 wrote:

I do not have an ib but i have heard that because of the way an ib works it does not get really loud outside the house. I remember reading one persons description of their ib setup on the cult being much quiter outside the house than their older ported setup.

I read that as well. I think it relies on many factors though.

**Avus_M3** · **03-05-08, 04:20 PM**

Quote:

hifiger wrote:

If you plan to run your IB higher up, >20hz at max pressure levels, you may notice some chuffing--and burning of VC's

, but if you stay with a lower tuning (EQ) instead, ~10hz, you will likely hear less if any chuffing. This is based on the assumption that chuffing is due to airspeed, and airspeed decreases with frequency reproduced, and increases with amplitude. Personally I would not worry. If you had a Sonosub that could have that much radiating surface area (port and driver) you wouldn't be worried would you? If you are truly looking to get the best advice for the SD vs manifold opening size question, you should make a visit over to the IB Cult forum and talk with ThomasW, Chrisbee and the guys over there. .02c

Edit: and good luck with your project. The last guy who made a quad Q18 IB had to switch to large sealed cause his house was vibrating to vigorously. He had installed the manifold in a wall to an adjacent room, and the backwave was too much for him.

By the way, is your planned backwave area an attic space?

Well, I redesigned the manifold so it is 19% bigger (close to 75% of sd of subs). I really don't think it is going to be an issue

As for the backwave it is going into isolated attic space above the garage...looking good!!!!

Quote:

v1rtu0s1ty wrote:

Glad yours is almost done. I haven't installed mine yet. I don't have the theater yet. By the way, does dip mean drop?

Look at my room response too since I don't have any walls yet in the basement.

http://restricted.dyndns.org/qscamp/...a_REW_Tool.jpg

Yes, dip means drop.

It WILL be done soon...can't wait :drooool

**Avus_M3** · **03-21-08, 03:48 PM**

Well...FINALLY an update!!!!!!!!!!!!!!!!!!!!!!!!!

I've been trying to line up a truck to haul the sheets over to my buddy’s house and line up a time with him to use his table saw, routers, etc because he has a fully stocked setup.

That didn't work too well

. It doesn't matter too much anyways as I haven't had the time to do it. I have been busy working/screwing around with my car, school, and I also had a friend who got out of the Chair Force recently come out here to Cali and move in with us for awhile.

**Avus_M3** · **03-21-08, 03:49 PM**

On to the good stuff...my brother-in-law was over last night and I took the opportunity since I have another set of hands to finally kick this project off (since I am not using my friends’ setup anymore)

.

We started right before dinner time and ended a little after 3am

(many beer breaks in-between to wash down the dust in our mouth and throat. I also took the opportunity to clean my nose, ears, eyes, and clear my lungs.

We actually got incredibly accurate cuts using a simple rip fence (mdf sheet) for my skill saw, my trusty compass, and a jig saw to cut the holes

.

I did end up acquiring a very nice router and bits from the friend who was going to let me use his tools though! We used it to round over the inside edge where the speakers will sit flush to. I don't know if I want to round over the exterior edges yet?

**Avus_M3** · **03-21-08, 03:50 PM**

Anyways, here some pics of the progress!

Rip Fence setup:

Tools of the trade. My trusty compass:

Drawing the circle:

**Avus_M3** · **03-21-08, 03:50 PM**

Cutting the first circle out:

Circle finished:

Looks Pretty Good!

**Avus_M3** · **03-21-08, 03:51 PM**

Round the edges:

Another angle:

Brace being drawn up:

**Avus_M3** · **03-21-08, 03:51 PM**

BTW I eliminated the exterior sheet (3 layer) of OSB. Just not needed. Besides, I could use that sheet for something else.

All that is left is to cut out the last 2 circles which are already drawn and cut out the brace (most difficult part). Should be finished, assembled, primed, painted, and installed soon (Seriously this time)!

**Mike P.** · **03-21-08, 04:01 PM**

Looking good! Keep the pictures coming.

**Avus_M3** · **03-21-08, 04:19 PM**

Quote:

Mike P. wrote:

Looking good! Keep the pictures coming.

Sorry I didn't take more pics but I was getting zombie eyed between the dust and general lack of sleep

.

**Avus_M3** · **03-23-08, 02:55 PM**

I couldn't work on it last night since I was at a wedding but might get some time in tonight. Either way, a lot will get hammered out tomorrow

I am still searching for options on what I am going to do about the manifold opening. Any thoughts?

**Avus_M3** · **03-25-08, 03:45 PM**

More Updates!!

I didn't get as much time as I wanted to on the manifold but still did a lot (another late late night/morning). Unfortunately, my wife’s car blew a heater hose and I had to troubleshoot that first

.

Anyways, we finished cutting the OSB and cutting out the brace which was a pain. Since I don't have a 1/4" round over I had to use the 1/2" that my buddy gave me with the router. I adjusted the depth pretty high so it took the corner edge off but still had a solid surface for the bearing to ride on.

**Avus_M3** · **03-25-08, 03:46 PM**

After that, I hand sanded the brace down to round over the interior cuts and take the slight edge off the router left. For using the tools available (drill and jigsaw) I would have to say it came out pretty **** good - best that can be expected at least.

I also test fitted the subs in and they are nice and snug. I am really noticing why some people go insane on bracing for massive ported and sealed boxes. I forgot how flimsy MDF can get. The manifold really really locked together when we added the brace though. I don't see how people get away designing these manifolds without them??

The span for the 2 woofers in each side seriously needs a tie point to hold it together.

**Avus_M3** · **03-25-08, 03:47 PM**

Also, after assembling the box last night I decided I am going to add the third layer for a couple reasons:

1) I have the wood - might as well use it?
2) I have the space in the attic _ not going to be an issue
3) After seeing just one of these monsters loaded, I feel it really needs it
4) I want more than a single sheet of OSB to mount to so I was going to cut blocks for the rear mounting - why not just cut a whole side sheet??

**Avus_M3** · **03-25-08, 03:47 PM**

Anyways, here are a few of the pics:

Cutting the Brace

**Avus_M3** · **03-25-08, 03:48 PM**

Finished Hand Sanding the Brace

**Avus_M3** · **03-25-08, 03:49 PM**

Starting assembly

Brace Install

It squared up pretty nice!!

**Avus_M3** · **03-25-08, 03:49 PM**

Laminating the sides

**Avus_M3** · **03-25-08, 03:50 PM**

Test Fitting The Sub

**Avus_M3** · **03-25-08, 03:50 PM**

Sooooo Sexy (Magnet Protruding Out)

Coming along real nice!!

Advertisement