4 18" 5400's and 8 passives "WOW!"

**ISLAND1000** · **03-01-08, 08:03 AM**

Quote:

robertcharles123 wrote:

how big of a roundover is usually used for the recess baffle?

I don't know if there IS a standard roundover in the industry but I'll take whatever YOU decide because your project is incredible no matter what you do from here on in.
So you've got 6 huge holes in each cabinet . . . . . each cab gets two drivers and 4 PRs right? If my math is correct one face of each cab will have two drivers and one PR, right? Or . . . . are you going to have opposed drivers, one on each side of the cab with two PRs per side? Will the drivers be in the middle hole or one of the ends?
You've got to tell us ahead of time before you mount the drivers and PRs. Once in the cab we won't be able to tell what's driver and what's PR.

I was thinking last night about the many different driver/voice coil hookup configurations you'll have. If you decide to go with the 2 Crown I-Tech 8000 route on the amps, you'll have 4 separate amplifier channels to drive 8 voice coils and the ability to PEQ a curve for each driver . . . . .

Maybe you better arrange to mount a speaker terminal on the outside of the box to access each driver AND each voice coil.
Maybe you'll need (4) Crown I-Tech 8000 amps! LOL

**Geoff St. Germain** · **03-01-08, 08:55 AM**

I'm sure he's doing 1 driver and 2 PRs per side.

I'm not sure I understand where you want to put the roundover. Is it around the lip of the driver cutout in the plywood? I'm not to sure what this would accomplish, but I'd make sure to use a roundover that isn't going to interfere with the driver mounting hardware. If that is where you're talking about I'd be inclined not to do a roundover.

**phaseshift** · **03-01-08, 10:12 AM**

Robert,
I think what you are doing is cool and I can see that you are really enthusiastic- I wish doing speaker work was still as fun for me as it is for you now. That said, I want to mention something that I am observing in your photos-

Your cabinets look good, but they need a lot of braces. For instance, if someone else did a system like your using low quality, low excursion drivers, they would be looking at a significant amount of displacement even though the drivers did not move a long way.

In your case, you are using several good quality drivers with a pretty high Xmax / Xmech. If you really drive those things out near Xmax, you are very likely going to have cabinet issues in terms of reliability and I would bet you lunch that without braces, you will have acoustic problems (cabinet noise). Keep in mind that all that cabinet movement is either out of phase or lagging somewhat; regardless of which, it is bad for your sound quality and cuts into your SPL. In your case, you should have plenty of SPL, but I am concerned that you may have some cabinet issues to deal with. Specifically across the big opening in the nicely cut oval windows on the inside of the cabinets. It will not look as nice, but bridging that with a couple of 25mm X 50mm strips of MDF well glues and screwed in place will make that area significantly stiffer and likely benefit the quality of the end result.

You are mentioning the current draw on the amplifiers as a concern – ( someone was ). With the Crown and QSC amplifiers, I am pretty sure that you can get a power curve on them and if not, you can do it yourself with a big resistor, but you will need to be careful to get the right stuff. A cheap Fluke meter like a 187 will be adequate for the voltage and will catch and hold with adequate speed. You will need that for the output voltage and for input voltage, you need an inductive (clamp on) meter; again, Fluke has a few very good ones for under $500. Actually, you can use your PC as a signal source or buy a test CD and go that route for the signal input to the amp. Simply look at the voltage into the resistor, do the math and you have your wattage. The current will be a direct read if you have the right meter.
What you need to consider there is if your GFI will see the sudden change in current due to transients or other rapid changes in current as a fault in the circuit and trip the breaker. I am guessing that you would not have this issue if you are using active crossovers so that the amps never see the transients out above 200 Hz or so.

Please take my comments as constructive; I really get a kick out of that sort of stuff.

**Josuah** · **03-01-08, 01:32 PM**

Quote:

robertcharles123 wrote:

the berenger wouldn't even be enough to get the 5400's going before clipping the amp. Chasw98 tested the berenger at the avs forum, and I will post his link if you like. He gives real numbers for the amps he tests and he is unbiased.

I'd be interested in that link. I'm using a single EP2500 myself and haven't driven it to clipping, based on the LEDs, even though I'm boosting below 20Hz using a DCX2496. I'm driving four 15" drivers with it.

**Warmon** · **03-01-08, 04:27 PM**

Quote:

robertcharles123 wrote:

how big of a roundover is usually used for the recess baffle?

Nice work so far! IMO. chamfered edge on the MDF baffle will look better than a roundover. You'll want the bottom edge to be about 1/16" above the mounting ring on the sub.

**robertcharles123** · **03-01-08, 11:46 PM**

I used about 2/3 depth of a 1/2 roundover bit. I have to load pictures, but the finish looks clean and very acceptable. I was wondering about the bracing as well. My only concern was the 20"x12.5" panel peices in each chamber. I was going to cut extra strips of material and place them across each panel to shorten the size of each to 10"x12.5". As far as the braces that are there so far, They seem to be tough as heck. When we bang on the cabinets, they are "dead". I'm still deciding about that., but these guys are getting extremely heavy. I will end up with 2.25" speaker baffles. and 1.5" side panels currently with the largest piece of lumber not having a brace being 20"x12.5". I hope it will be enough,but I am considering other options.

**robertcharles123** · **03-02-08, 12:19 AM**

Island,

1 driver and 2 passives per side of each cabinet. Driver in middle passives top and bottom. Everything is symmetrical and mirror image.

I was going to wire entire cabinet 8 ohms. That is the plan, but could change.

Thanks,

Robert

Roundovers

**robertcharles123** · **03-02-08, 12:27 AM**

heres the link http://www.avsforum.com/avs-vb/showthread.php?t=855865

**robertcharles123** · **03-02-08, 12:29 AM**

The roundover is on the third layer of mdf.

**robertcharles123** · **03-07-08, 12:51 AM**

Final mockup of brace scheme. This is it. Going forward. Side has been installed. Bracing to follow

**robertcharles123** · **03-20-08, 01:03 AM**

Hurricane nuts are in and braces are almost complete.

**atledreier** · **03-20-08, 01:46 AM**

That's one crazy build. Gonna rock the house, and the house a block down. Awesome stuff.

**Geoff St. Germain** · **03-20-08, 07:48 AM**

Quote:

robertcharles123 wrote:

Dolly style casters are a good choice. Are you putting them onto the side or the driver end of the cabinets?

**ISLAND1000** · **03-20-08, 07:52 AM**

Yeah . . . . I think you're going to find that your best design feature is going to be those wheels. The addition of those hurricane nuts puts the weight of those cabs over my emotional limit but with the wheels on, you just pick up one end and roll "er" over to the otherside of the room if you want. So ingenius!

**robertcharles123** · **03-20-08, 08:24 AM**

The wheels will be placed on the wide rear panel. That panel is solid wood from top to bottom- no holes. The woofers will be on the sides. With the wheels and the handles, hopefully, they will be easier to move.

Thanks,

Robert

**ISLAND1000** · **03-20-08, 08:31 AM**

I thought they were going on an end so you could move them in an upright position right through a door if you had to, kinda like an appliance dolly.

**robertcharles123** · **03-20-08, 08:43 AM**

Yeah, just like moving an appliance. The woofers will be side firing, so they are the sides of the cabinets, and the front and rear are solid panels. The wheels are for the solid rear panel.

Thanks,

Robert

**Avus_M3** · **03-21-08, 04:52 PM**

O M G

That is completely nutty in a good way! I can only imagine what people think when they come over!!! Must be insane (read really really good) when you crank it to "11"!!!

**robertcharles123** · **03-31-08, 08:36 PM**

All braces have been placed in both cabinets. The layering is almost done on both cabinets. Hopefully, the actual structural part of this build will be done in the next 2 weeks. Pictures to come later. My camera is full today.

Good luck,

Robert

**a1161979** · **04-02-08, 10:38 PM**

Camera has been full for too long now... Please i need to feed the addiction

Hows it comming along Robert? I am really looking forward to seeing this build finished, im kinda getting sick of all the LLT build being posted around the place

Be sure to keep us updated

**robertcharles123** · **04-03-08, 01:52 AM**

I just purchased 2 Crown I Tech 8000's. Hopefully, I will now have enough power and I will be encouraged to finish the cabinets. Almost done with each structure. One more panel for each.

**a1161979** · **04-03-08, 02:23 AM**

Quote:

robertcharles123 wrote:

I just purchased 2 Crown I Tech 8000's. Hopefully, I will now have enough power and I will be encouraged to finish the cabinets. Almost done with each structure. One more panel for each.

Wow thats some serious current... You could just about weld with those

Please keep us updated, i cant wait to see finished photos and even graphs... Hint Hint

**imbeaujp** · **04-03-08, 03:11 AM**

Yeh, i can not wait to see the final result and graph !

Good work !

**a1161979** · **04-03-08, 03:14 AM**

Quote:

imbeaujp wrote:

Yeh, i can not wait to see the final result and graph !

Good work !

No its good work when we get more photos

Nah just messing... Great work

**robertcharles123** · **04-03-08, 09:02 AM**

Enough power?

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