$325 Lab 12 based PA tapped horn ~ 35Hz extension

[picowallspeaker]

What we got is the free air resonance of a 265 g membrane...

 

[maxolini]

you mean that the SKAR Su.... Donkey Ballz ?

 

[Booger weldz]

It doesn’t ‘suck’, anymore than the you drivers don’t purchase and speaker boxes you still haven’t made 😝

they easily survive in those really demanding/harsh/fatiguing sounding paraflex designs we experimented with for awhile... but nothing sounds particularly ‘good’ in those(??) so who knows if a ‘tapped horn’ is going to sound any ‘better’ when those are just a mess of resonances and cancelations after 3 x Fb where the paraflex version fills it all in? (But paraflex has no bottom end , and rolls off from like 50 hz on down ??)

hurry up and build one of each and let us know 🙏🏻🙏🏻

 

[maxolini]

Is it possible to swap drivers on the Pal12 once is already finished or your need to add an access panel

 

[weltersys]

Post 804 and you never looked at the plans or photos?

The PAL12 driver can be accessed through the horn mouth.

Different 12" drivers may have different bolt hole and baffle cutout dimensions.

 

[Booger weldz]

That skar driver is exactly 11.5625” center to center (8 holes)

 

[maxolini]

I found a demo BMS 12S305 at 50%off, same cost of a DDX12
I will hit the trigger on it

https://www.bmsspeakers.com/index.php-33.html?id=bms_12s305

 

[BP1Fanatic]

These low Q numbers = smaller enclosures!

Electrical Q Factor:	Qes		0.278
Total Quality Factor:	Qts		0.265

 

[Booger weldz]

Is that cone up to the task? It’s like 90 grams and ’protected from water’. I see it’s ‘carbon fiber however ?


(compared to the suggested BR design)

 

[BP1Fanatic]

Bandpass rules!

 

[maxolini]

These low Q numbers = smaller enclosures!

Electrical Q Factor:	Qes		0.278
Total Quality Factor:	Qts		0.265

so that means is for like a HT small cube like sub, not a horn like the PAL12

ok the LAB12 have

Electromagnetic Q (Qes)	0.39
Total Q (Qts)	0.38

so means that i need to find drivers with Qes and Qts above 0.35 at least ?

ok the LAB12 can take only 150 watts to reach 12.8mm XMAX

the 12S305 can take double... 300w to reach xmax of 11mm

 

[maxolini]

the below response is nice for a BOSE type of 2.1 system that have those 2 tiny 3" satellites crossed 200 or 300hz

 

[Booger weldz]

But this looks like the acoustical version of venerial warts 🤡

 

[BP1Fanatic]

🤣😂

 

[BP1Fanatic]

so that means is for like a HT small cube like sub, not a horn like the PAL12

ok the LAB12 have

Electromagnetic Q (Qes)	0.39
Total Q (Qts)	0.38

so means that i need to find drivers with Qes and Qts above 0.35 at least ?

Small enclosures in general.
Drivers with Q's <0.30.

 

[maxolini]

So why the BMS "stimulate" ok in HR
Or at least that's what I think.

Any downsides of using a small enclosure spec driver in a bigger volume cabinet, in this case the PAL12

 

[BP1Fanatic]

I think in 1 of these big TH threads (SS15, THAM15, etc) someone mentions pro audio drivers with high fs (I'm assuming the 40-60hz range) and low Qts are great for TH's.

 

[maxolini]

Well this BMS have an Fs of 29

 

[maxolini]

Ok from post#1 in this thread we got the specs of
"
Now that the sub is constructed and tested, we can post some final specs.
Operating frequency: 34Hz----120Hz +/-3db
Dimensions: 30"x38"x15"
Impedance: 4 ohms
Power handling: 400w rms, 800w program High pass 32Hz 24db/octave minimum"

How come you can feed 800w to the LAB12 and on the HR sim it hit xmax at 150w, what i am missing here 🤔

 

[BP1Fanatic]

Calculate Eg = wattage and the SPEAKER's Re, not the amp load...8 ohm, 4 ohm, or 2 ohm.