Getting started with IB project...

**Sonnie** · **07-03-06, 03:14 PM**

You guys are talking all this .5 Qts stuff and the highest I've seen in any of the drivers I've looked at is the .447 of the dual 4ohm SoundSplinters. Where you getting .5 and .7 at? What am I missing?

Quote:

Jacen wrote:

So, Sonnie, when do you pull the trigger?

I'm probably a few weeks out. I've still got to do some more research, study a little more, make sure I got all my ducks in a row sorta thing. I'm still undecided on drivers right now... although the SS's seem like the way to go.

**JCD** · **07-03-06, 03:35 PM**

Quote:

Sonnie wrote:

You guys are talking all this .5 Qts stuff and the highest I've seen in any of the drivers I've looked at is the .447 of the dual 4ohm SoundSplinters. Where you getting .5 and .7 at? What am I missing?

I haven't seen those either.. I've been trying to find a Q closer to .38ish based on the recommendation I got from someone a while ago, plus the FAQ on the Cult.

Quote:

Sonnie wrote:

I'm probably a few weeks out. I've still got to do some more research, study a little more, make sure I got all my ducks in a row sorta thing. I'm still undecided on drivers right now... although the SS's seem like the way to go.

Yeah, I've been waiting till I am totally ready to pull the trigger before I go looking for drivers. Thomas keeps alluding to some new 18" drivers -- with a huge xmax, great sound quality, cost $1.99/each, will make a cafe latte for you, etc -- coming down the pipe in a "couple of months". It's KILLING me..

JCD

**Exocer** · **07-03-06, 03:47 PM**

I may be wrong but I have a feeling you guys may be confusing Qtc and Qts with eachother. Qts is the driver paramater (the driver's Q at FS), whereas Qtc is a design goal and can be adjusted with Vb of the enclosure being used. In this case we're talking huge Vb which in essense translates into a lower Qtc design.

**JCD** · **07-03-06, 03:50 PM**

Quote:

Exocer wrote:

I may be wrong but I have a feeling you guys may be confusing Qtc and Qts with eachother. Qts is the driver paramater (the driver's Q at FS), whereas Qtc is a design goal and can be adjusted with Vb of the enclosure being used. In this case we're talking huge Vb which in essense translates into a lower Qtc design.

I was talking Qts..
I did miss that Jack Gilvey mentioned Qtc though.

JCD

**FlashJim** · **07-03-06, 03:53 PM**

Quote:

JCD wrote:

And 8x15" drivers.. I keep getting that scene in Back to Future running in my head.

JCD

LOL ... crank everything to "10" and let it rip! Unless, of course, you're Spinal Tap.

Jim in Houston, dreamin' of "11" ...

**Jack Gilvey** · **07-03-06, 03:54 PM**

Quote:

You guys are talking all this .5 Qts stuff and the highest I've seen in any of the drivers I've looked at is the .447 of the dual 4ohm SoundSplinters. Where you getting .5 and .7 at? What am I missing?

Some IB-specific drivers are higher than usually seen, like the 0.65 of the Dayton IB 15: http://www.partsexpress.com/pe/pshow...TOKEN=82225160

While it's rarely mentioned or done, you can actually run a dual voice coil driver at any Qts between its rated one and approximately double that by changing the resistance across one of the voice coils. You'd want to check with a manufacturer to se what they think,though.

http://www.adireaudio.com/Files/Tech...OOperation.pdf

Eq is another option, since your Qtc just describes the shape of the final curve.

**Exocer** · **07-03-06, 03:56 PM**

Quote:

JCD wrote:

I was talking Qts..
I did miss that Jack Gilvey mentioned Qtc though.

JCD

Ohhh, ok. Just trying to help

**Jack Gilvey** · **07-03-06, 03:56 PM**

In IB, when Vb is more than 4x vas, Qtc = Qts for all intents and purposes. The IB ideal is that the air behind isn't affecting the driver.

**Sonnie** · **07-03-06, 03:58 PM**

Quote:

JCD wrote:

Yeah, I've been waiting till I am totally ready to pull the trigger before I go looking for drivers. Thomas keeps alluding to some new 18" drivers -- with a huge xmax, great sound quality, cost $1.99/each, will make a cafe latte for you, etc -- coming down the pipe in a "couple of months". It's KILLING me..

That's most likely John's drivers (AE) and from what John told me he's a good 3 months out from having the materials to get started building them. It could be 4-5 months before we see those, but that will be here before we know it.

Yeah... I'm talking Qts too:

T/S Parameters
Dual 4 ohm

Qts: 0.447
Qes: 0.508
Qms: 3.728
Fs: 27.487 Hz
Re: 6.1
Ls: 5.303 mH
Lp: 6.268 mH
Rp: 12.39
Dia: 330 m
(% shift) 37.5 %
Vas: 148.8 L
Mms: 231.4 g
Cms: 144.8 u
Bl: 21.90 T*m
n0: 585.0 m
SPL: 89.67 dB
Sd: 0.0806 m^2
Xmag: 27.4 mm
Xmax: 24.6 mm

Hey Jim... I want it to pop my eyeballs out and give me an extra heartbeat!

**Sonnie** · **07-03-06, 04:04 PM**

Look... I'm a bonafide country redneck hillbilly.... haven't you guys figured that out yet?

Don't keep confusing me more... just tell me like it is. Spell it out in hillbilly language. That's like maybe 5th grade or so.

**rlammi** · **07-03-06, 05:33 PM**

Hey sonnie ,I am right there with you and the Pink Floyd ,dark side of the moon will sound awesome on 8 15's ,my 4- 12's play it way better than the old sub I had and I haven't EQ'd it yet still working with rew and the bfd ,one I get the spl meter I will get some readings and let every one know how it goes .Look forward to seeing your system up and running .

Ron

**Sonnie** · **07-03-06, 07:47 PM**

Thanks Ron... I'm trying to be patient... something hard to do for me.

You gonna have to break it all down for us on your setup. I since another IB thread layin' it all out for us with some pics.

**rlammi** · **07-04-06, 12:09 PM**

Hey Sonnie,

mine was a project in the making from getting the WAFto go along with it .I am using
Gr-research 12's in a manifold here are some photos of the I/b and the other speakers I have made .http://community.webshots.com/user/rlammi100

good luck look forward to here how it sounds .
Ron

**Sonnie** · **07-04-06, 06:28 PM**

Nice work Ron... does GR make any 15's that would be suitable for IB?

**rlammi** · **07-05-06, 09:36 AM**

Sonnie ,

Not to my knowledge ,I am not even sure theses were going to work until I fired it up ,the speaker was in the box sub with a pr . I just took a chance seeings how the xmax wasn't to low ,they sound great .Just picked up and spl meter so maybe friday I can try and get my bfd somewhat dialed in.My room isn't super huge ,but man I envy you 8-15's would crumble my house .

Ron.

**Brian Bunge** · **07-08-06, 02:32 PM**

Sonnie,

Keep in mind that 8 15's such as the SS units will be capable of doing serious structural damage to your home. If you're cool with that, then by all means press on!

I do know that ThomasW has said that he's never tried to find the limits of his 12 Shiva IB due to a large plate glass window in the room that he has no desire to replace.

Also, it would be a good idea to model the drivers you are considering to see just what your power requirements/power limits are. I can do this for if you'd like.

**Sonnie** · **07-08-06, 05:43 PM**

Yeah... I may just try 4 to start with since I was planning on doing two manifolds of 4... but I do like overkill. I wonder how my room will work with the setup anyway. Have you looked at my HT pics/contruction?

My HT room is in my garage (1/2 of the garage). No windows and even no large windows near it. We do have two normal size windows in the garage on the opposite wall of the HT room. I'm not too worried about he room itself... it is built like a tank. I'd probably be more worried about the attic area than the room... and maybe on into the rest of my house.

I also wonder about my projector being ceiling mounted and vibrating. There may be a plus side to the way I built my room though. The original garage ceiling was left in place and a new ceiling was built for the room. The new ceiling built from 2 x 6's is about 1/4" from touching the garage ceiling. I tried to basically decouple the room from the house, other than the slab and the outside wall that has the brick on the back side of the house. I did remove that wall and add staggered studding to it. The entire room, walls and ceiling, have 2 sheets of 5/8" drywall screwed in every 4-5". I few folks thought I went crazy with screws... but again my goal was to make it as solid as possible.

If you can model the drivers that would be great. What do you need from me. This is assuming I go with the SS drivers, which I just haven't found anything comparable yet... that didn't cost a lot more money that is.

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