About to start 4 Tuba 24's double BP102 4Ohm!

[Bill Fitzmaurice]

What's wrong with the setup of Omnis over T24s, if everythings crossed over and EQd appropriately?

They're twice the size of the OTop 12 with less sensitivity. They're called 'full range' because they're just that, meant to stand alone with no sub. If you're running subs then Omni 12 is the wrong tool for the job, a waste of pack space.

[netwerks]

Hi DJPhatman I am not trying to dish your point I know where you are coming from with this, this project I have been planning since late 2010. Maybe it's a wrong setup but I am not trying to prove a point as to this setup but it is a pleasure to build Bills designs and when people are on the dance floor enjoying themselves those charts you keep showing just don't mean any anymore. I know this system will be loud especially the amps and other electronics I will be buying in the next month or so. Believe me I know where you are coming from no disrespect maybe my system is all messed up mixing cabs. I have a couple of shows this Fall 2012 and they will be used till the end of the year. There are 3 systems I can have on hand from people I know in the business, I plan to start gathering wood again (BB) for my next project a large 5 way sound system using the T36's (15mm exterior glue/12mm interior) as subs loaded with Faital Pros neo 15's, again it is just a plan and maybe I am doing something out of the norm for this site but I like to experiment, but I know it will be big and sweet sounding, and LOUD!!!!

The chart shows you will only get a slight measurable performance gain by adding subs. You'd probably be better served to build a second pair of omnis rather than adding subs if you insist on a full range cab on top....

[bitSmasher]

What's the highpass on omni12? Looking at the size of it, and it not being a full on horn, can't be same as T24.

That chart is 1w/1m sensitivity. More importantly, what is max output of both the O12 and T24?
If it were as simple as the chart suggests, we should all build Omni12 subs not big complex folded horns.

[Gregory East]

I know what the chart is. What it doesn't say is where the omni gives up the ghost due to overexcursion, read the question.

[bitSmasher]

Sorry, I only quoted your post instead of including DJPM's initial statement with the chart - apologies for confusion as I was moreso addressing him... I'm with you in wondering what the usable output is from an O12.
The O12 plans don't state a high pass, though Bill did mention here

Limiting and high passing aren't really necessary, as you'll hear the woofer(s) complain if you push them too hard. Just pulling the EQ below 40Hz down all the way is sufficient

How hard, and how low?

Not trying to be argumentative or pretending I know what I'm talking about (as I'll openly admit I don't! ), just hoping to learn from the discussion.
In this case, a sensitivity chart is comparing a full range box to a sub, and I'm curious as to the other parameters involved when combining different types of speakers as a system.

[Bill Fitzmaurice]

That chart is 1w/1m sensitivity.

It's 2.83v/1m, as are all our charts unless otherwise noted. With a 4 ohm 2x10 that makes it 2 watts.

[DJPhatman]

Hi DJPhatman I am not trying to dish your point I know where you are coming from with this, this project I have been planning since late 2010. Maybe it's a wrong setup but I am not trying to prove a point as to this setup but it is a pleasure to build Bills designs and when people are on the dance floor enjoying themselves those charts you keep showing just don't mean any anymore. I know this system will be loud especially the amps and other electronics I will be buying in the next month or so. Believe me I know where you are coming from no disrespect maybe my system is all messed up mixing cabs. I have a couple of shows this Fall 2012 and they will be used till the end of the year. There are 3 systems I can have on hand from people I know in the business, I plan to start gathering wood again (BB) for my next project a large 5 way sound system using the T36's (15mm exterior glue/12mm interior) as subs loaded with Faital Pros neo 15's, again it is just a plan and maybe I am doing something out of the norm for this site but I like to experiment, but I know it will be big and sweet sounding, and LOUD!!!!

What you will be doing will give less bass, not more. The >100hz output of the O12 is greater than the T24s. Since the O12 will take 3X the power, you are adding T24s for no good reason.

What you are doing, and how you are running your system, is under your sole control. We can only advise you on what is wrong and right about it. We can't force you to do it right, use it right, set it up correctly, properly use system processing, what power to use, etc. All we can do is provide sound advice and reasons for what we advise, it's up to you to heed the advice and reasoning provided.

[CoronaOperator]

Just to be objective, the Omni 12's will lose considerable bass pole mounted or mounted up high as they should be. The 4 dual tuba 24's can take advantage of proper placement and corner loading and 4 duals will have considerable more Vd than the omni's. Having the omni12's by themselves also is a nice full range rig should the need without subwoofers arise.

Its not the rig I would get into as it was mentioned, it is a poor use of packspace and not scaleable but if the OP already has the omni's he may as well use them for now.

[WB]

Just to be objective, the Omni 12's will lose considerable bass pole mounted or mounted up high as they should be. The 4 dual tuba 24's can take advantage of proper placement and corner loading and 4 duals will have considerable more Vd than the omni's. Having the omni12's by themselves also is a nice full range rig should the need without subwoofers arise.

Its not the rig I would get into as it was mentioned, it is a poor use of packspace and not scaleable but if the OP already has the omni's he may as well use them for now.

This quote sums up my thoughts so thanks for saving me typing it out.
I do think this set-up could and should sound good if properly setup, but still, I would do what Bill says and use OT12's. Now a 5 way system with Tuba 36's..............

If it were as simple as the chart suggests, we should all build Omni12 subs not big complex folded horns.

Where horns rule is when coupling multiple cabs as djlivex will be doing. (By the way djlivex, nice build pics, lookin' good) I like small pack space and don't need multiple cabs so I chose the Omni subs over a horn. I believe a single Omni sub will give more bass than a single horn sub of the same cab volume.

I know what the chart is. What it doesn't say is where the omni gives up the ghost due to overexcursion, read the question.

From my experience with my O12 subs (3012LF) response drops like a rock at 50 Hz similar to how my OT12 response drops off at 125 Hz. While the response was way down at 40 Hz vs 50 Hz, I was still able to feed a full 60 volt sine wave at 40 Hz and it wouldn't fart out. Knowing this I never hesitated in boosting 40 Hz to even out the response. I just want to note that this is my experience only and Bill's chart doesn't show this.

[djlivex]

Thanks WB, I hope I did not start something for everyone to throw words back and forth at each other I just wanted a little oomph on the bottom that is why I spent the money on 4 Dual loaded T24's. Also I had this cut by a pro woodworker friend of mine and it is great fitment wise but having it leaned on one side in the garage for a month before building did warped my BB's. So now I am building slow to make sure all the lines line up in my paper exact scale drawing, should be a very nice build I might add. Thanks for looking more build pics to come panels 3 in 2 of the 4's in!

[djlivex]

So far only a couple of panels in, do you guys ever spread the PL to keep the gaps closed due to a very slight warp? Anyway it ate some of my skin on my right index finger. Also I've had this 5 PL tubes since last summer is it still good to use (left over from friends T48 build), or should I buy new ones these are unopened tubes by the way? If you see dry wall screws on the panels they will be removed and filled with PL adhesive. By the way the clamps are on there for 24 hours at least for alignment and clamping power. That's all I can do today it was 103 in my building room, whew warm here in Florida middle of the day!
http://www.flickr.com/photos/60536137@N ... hotostream
http://www.flickr.com/photos/60536137@N06/7230282168/
http://www.flickr.com/photos/60536137@N ... otostream/

[Gregory East]

Eaten skin could lead to sensitisation, if that isn't already happening, next stop is allergic reaction to all kinds of stuff, if it wasn't for the misery I endured I'd leave it out since the dismissal, the rest others will fill in for you, but I urge you to keep pl off yourself at all costs and ventilate the hell out of your workshop.

[djlivex]

Nothing really happened the last time, but I will wear a surgical glove from now on, ventilation is pretty good in that room with an overhead fan.

[bassmonster]

I took a good bit of skin off my knuckle while building T24s today and got PL in the wound on accident...it stung real bad but nothing else happened, I just wiped it off the cut. No reports of eaten skin either... Although, my hands are a mixture of regular skin color and darker tan color from the PL embedding itself in my fingerprints and wrinkles. That'll be there for another week or so.

We didn't have any issues with the PL fumes, big fan running and garage door open. Yup, it was about 90 F and 60% humidity today...

[el_ingeniero]

Eaten skin could lead to sensitisation, if that isn't already happening, next stop is allergic reaction to all kinds of stuff, if it wasn't for the misery I endured I'd leave it out since the dismissal, the rest others will fill in for you, but I urge you to keep pl off yourself at all costs and ventilate the hell out of your workshop.

I don't think PL fumes are a huge issue. Bondo fumes on the other hand ...