[knuckle_head]

Searched and read for months - backed my way in here.

A bit of an introduction - I am a bass builder and bass string manufacturer. I lend my interests to extending most instruments lower. My personal instrument is a 4 string bass tuned to 20 Hz E. My last trade show I displayed a bass that was tuned to 12.98 Hz G#.

I am just under way with my full range cabinet. It's a 3-way 15-6-1 that is shelf ported to get me near 40 Hz up to about 12 kHz. I built a ported sub some years back that has been good fun, but I want to build something that is better equipped for the reference rig I hope to have. I am a crippled designer however, in that I am a Mac guy and have had zero access to modeling software since MacSpeakerz was left in the dust.

Conventional wisdom in the MI cabinet world is that if your cab carries the second harmonic you'll have as much of the sonic structure as you need to pull off good bass representation. The three way I am building will support the instrument I have but isn't enough for the one I intend to build.

What I want to end up with is a sub that is as close to flat as I can get it from 20 Hz to 45 or 50 Hz. I have 1400 watts to use at 4 ohms (peavey dpc1400 bridged mono) and I own a Dayton Titanic 15 MkIII. I intend to come by a Behringer DCX2496 for crude analysis and crossover control.

I have to believe HT is the right place to look - the best solutions on spec I have run across are HT solutions. I have been blessed to have had access to Bag End ELF and Infra equipment, and while not flat it did let me in on the fact that there is much experimenting to do.

Any good souls willing to point me? I've been prepared to do a variation of the Titanic 15 sealed kit, but have been intrigued of late by what I've read about ported sonotubes.

 

[Mike P.]

Welcome!

Since you can't wire two Titanics for a 4 ohm load, how much power does the amp put out per channel into 4 ohms?
If you want strong 20 hz performance you can figure on 11 cu.ft. of space per sub tuned to 20 hz. Shown is one Titanic with 600 watts of power and a subsonic filter at 18 hz.

To give you an idea of the size, a 22" diameter sonotube would be 59" tall which includes 4.5" tall legs.

 

[robbo266317]

Welcome to HTS

Cheers,
Bill.

 

[knuckle_head]

Thanks for the welcome.

My Titanic is a 4 ohm speaker and the amp is a 1400 watter at 4 ohms - I expect for a number of reasons that I'll likely not be able to use all 1400 watts. I'm just hoping that appropriate power delimiting will get me close to 800 watts without destroying the driver.

The three-way this will support is very efficient - my intent is to limit program through it to 300-350 watts in the hope that the sub will be able to keep up. I will set parity at what the sub is capable of.

My existing sub is a direct radiator that is 8.81 ft^3 - I've long ago forgotten what I tuned the box to, but it has a single port that has a 1.875" diameter at 3/4" long. I've not been able to analyze it real-world so I truly don't know what I have but it modeled down to near-19 Hz flat if memory serves.

 

[Mike P.]

Thanks for the welcome.

My Titanic is a 4 ohm speaker and the amp is a 1400 watter at 4 ohms - I expect for a number of reasons that I'll likely not be able to use all 1400 watts. I'm just hoping that appropriate power delimiting will get me close to 800 watts without destroying the driver.

My mistake, I misread your initial post and thought you had 2 Titanics. Since you only need 600 watts to reach Xmax with one sub in the modeling shown above, what does one channel of your amp produce at 4 ohms?

 

[knuckle_head]

My mistake, I misread your initial post and thought you had 2 Titanics. Since you only need 600 watts to reach Xmax with one sub in the modeling shown above, what does one channel of your amp produce at 4 ohms?

It's rated at 550 program - 700 peak per side.

If it were tuned a bit higher or lower would I be able to drive the Titanic a bit harder/give it more juice?

The ideal solution is two of these it's looking like.

Edit; I gotta say, that modeler is killer - gives you the tilt height clearance too. Just brilliant.

 

[Mike P.]

11 cu.ft. tuned to 22 hz will take 800 watts with a subsonic filter at 21 hz. You'd gain a couple of db's above 20 hz and lose a couple of db's below 20 hz compared to a 20 hz tuning. Anymore power then that and you're exceeding the subs rated Xmax and distortion increases.

 

[knuckle_head]

I like the curve better on the 20 Hz tuning - a second sub it is for higher dB . . .

The drawing indicates lipped caps top and bottom - 1" lip and 1" cap?

Thanks so much for jamming the numbers on my behalf.

Skip

 

[Mike P.]

One inch lip and 1.5" thick cap, two 3/4" thick pieces glued together.

 

[knuckle_head]

I can't thank you enough - I'll post pics when the building commences.

Skip

 

[Mike P.]

You're welcome. Looking forward to the build!