Mixing Different Mouth Width Tubas

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CFBIRD
Posts: 14
Joined: Mon Feb 12, 2018 9:13 pm
Location: Denver and Omaha

Mixing Different Mouth Width Tubas

#1 Post by CFBIRD » Sun Jan 06, 2019 12:56 am

Hello,
I have (3) dual Lab12 30" wide T60's in progress, as well as (2) DR250's
I have been wondering about building some single Lab 12 tubas with narrower mouth widths, one on each side R/L on top of dual Lab 12 T60's, as if they would be kick bins...and some DR250 stacked on top of those as well.

Since response would be different, I'm curious to know what the risks of combing would be in such a configuration, and to what extent?

I'll be doing a "dance stack" type of layout until I can afford truss to fly DR250's way high.

Venues are warehouse, or outdoor.
For indoor venues, I will be dedicating a lot of resources to sound absorbing panels.

My preliminary thoughts are that it should be good enough for intoxicated people having fun, and still better than most direct radiating set ups people use.

Thoughts? and Thanks!

<3ird

CoronaOperator
Posts: 1648
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: Mixing Different Mouth Width Tubas

#2 Post by CoronaOperator » Sun Jan 06, 2019 1:20 am

Nothing wrong with using different width cabs of the same type as they all have the same horn length.

Splitting sub stacks left/right however can give you wacky bass response that changes as you move about due to an interference pattern they will create. You may get heavy bass response in one spot and literally 3 feet over all the bass can disappear. I say may because indoors in highly reflective rooms, the reflections may even those nulls out. You also lose some output from the stacks not coupling. Just something to be aware about but in a warehouse, if you space the stacks far enough apart you will minimize those effects and even out the bass response.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

Grant Bunter
Posts: 6457
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Mixing Different Mouth Width Tubas

#3 Post by Grant Bunter » Sun Jan 06, 2019 3:14 am

CFBIRD wrote:
Sun Jan 06, 2019 12:56 am
Hello,
I have (3) dual Lab12 30" wide T60's in progress, as well as (2) DR250's
I have been wondering about building some single Lab 12 tubas with narrower mouth widths, one on each side R/L on top of dual Lab 12 T60's, as if they would be kick bins...and some DR250 stacked on top of those as well.

It seems lots of folk coming here building cabs (if it's about EDM), yes T60's, seem to think that kick bins are required. I'm not going to argue that, I don't do EDM.
The idea of Kick bins come from the 70's, essentially making a 3 way system to reinforce the lower mids.
When you build T60's, you partly eliminate the first harmonic of the kick drum normally reproduced by 18" or dual 18" direct radiators, it's a property of horn cabs.
125Hz is there, and still rising, as per the SPL charts, but steep slope crossovers around 90Hz makes it disappear.
The fundamental of a real kick drum is actually 50 to 70Hz (dependant upon tuning), the first harmonic thus being 100 to 140 Hz.
50-70Hz is the thump in a real drum, and that relates to tuning, but the associated "click" caused by the pedal striking/hitting the batter head is way higher, somewhere around 2.5 to 4K.
If you really need to do kick bins, think of the following;
T60's go beyond (and can be crossed above) 100Hz
If you use some of the same cab for different frequencies:
Set different parameters for the kick bins, don't use the same pass band as your dual loaded cabs, or
Crossover higher with all your subs (say 125Hz).
Sure that makes subs "locateable", but hey, it gets the job done.


Since response would be different, I'm curious to know what the risks of combing would be in such a configuration, and to what extent?

Response isn't different, output is.

I'll be doing a "dance stack" type of layout until I can afford truss to fly DR250's way high.

Given what I said above, think about your tuning options when building your DR250's.

Venues are warehouse, or outdoor.
For indoor venues, I will be dedicating a lot of resources to sound absorbing panels.

Really?
Use EQ, unless it's an install.


My preliminary thoughts are that it should be good enough for intoxicated people having fun, and still better than most direct radiating set ups people use.

Thoughts? and Thanks!

<3ird
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

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