# Lanzar 12” DC subs box questions



## wshymas (Jan 27, 2014)

Hello,
I have two Lanzar DC (old school 96ish)subs I made a ported box 3.2 ft3 tuned to 34 Hz the subs share the air space in the box. 
I have plotted the subs with WinISD and it said the best ported box is 0.196 with a 2” X 2” port 4.874 feet long. 
The best sealed box is 0.093ft3. How would you make a box that small?
What size would anyone recommend for these subs?

If this is not the Best place to post let me know where to repost 
THANKS.


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## ATOMICTECH62 (Jan 24, 2009)

You must have entered something wrong or have something set meters instead of mm or inches.I have done this myself before realizing my mistake.
It might be Vas.The tiny 2x2" port being 5' long is because the box volume is so small.


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## smgreen20 (Oct 13, 2006)

I agree, it's very easy to overlook the units of measure.


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## wshymas (Jan 27, 2014)

I re entered the sub in winISD and it look much better. The 2X2 port was one I was playing around with in WinISD. 
Okay after the correct units are in, the box size jumps to 5.5 ft3 @29 Hz for one sub, way to big for what I want. What about an isobaric set up? cone to cone (push/pull)
Any thoughts and/or criticism. 
I will do some searching as well.
THANKS


ps I already have 4 of the DC subs to work with. was planing on using two as backups.


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## wshymas (Jan 27, 2014)

RED is what I have now
GREEN is what WinISD sugests 
Lt BLUE is the isobaric with the box I have now


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## vwdave (Jun 12, 2013)

Try researching aperiodic boxes. Not a very widely use design but I've heard the. Before and they work well.

There's also sealed. You will loose output but it will be much smaller than a ported box.


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## wshymas (Jan 27, 2014)

Ouch my head hurts.....
that sounds like a cool way to make a box
I have the subs and port pointed at the rear of the car. 
Would the baffle work if placed in the same spot as the port?
Or do I need the baffle in front/rear of the cones/magnets?


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## 63flip (Oct 16, 2013)

The volume from the Lanzar spec sheet for the dc124 are .64-2.25 ft3 for a sealed enclosure and .8-4.7 ft3 for a ported enclosure. Those are for a single sub. It doesn't say what the port dimensions are but I'm sure they are some length of 2 1/2 tube since they didn't use slot port enclosures back then and that was the popular port method in the 90's.


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## smgreen20 (Oct 13, 2006)

LANZAR from that era used 4" round ports for the 12's and 3" round ports for the 10's. I'm unsure of the 8" and 15" subs.


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## The Dude (Mar 24, 2007)

I ran this through Bassbox Pro, these are the DVC DC-12's? It gave me 3.78 cubes for a pair, tuned to 43.7hz, under the High Output design option. Not sure if this helps.


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## wshymas (Jan 27, 2014)

THANKS



> I ran this through Bassbox Pro, these are the DVC DC-12's? It gave me 3.78 cubes for a pair, tuned to 43.7hz, under the High Output design option. Not sure if this helps.


Yes that does help. The subs are single voice coil 4 ohm (DC124 on the sheet I have)
How does it look if tuned to 33ish?



> The volume from the Lanzar spec sheet for the dc124 are .64-2.25 ft3 for a sealed enclosure and .8-4.7 ft3 for a ported enclosure.


I did use the Lanzar specs to “guess” a box size.

I did have a set of the DC loaded into a band pass box. But it seemed a little muddy to me so I built a new box that would fit in the car better and sound cleaner also wanted to get to my spare tire without having to move the box. So after the swap the sound changed (I knew it would change some) it seemed to have lost some bass on the top end. So I started to look at the plot to see if I had made a mistake. This is when I posted here about the extra small boxes. I still need to replace the front and rear door speakers and hook them up to the two opti100s. That should help with the perceived missing mid bass. I was trying to get a box that would have good SQ and a little SPL. I was tuning to 34hHz but I had entered some of the units wrong.
Once again THANKS for the input and help.


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## The Dude (Mar 24, 2007)

Could you post up the t/s specs that you have so that I can confirm that I am using the correct ones from BB ?


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## The Dude (Mar 24, 2007)

I have attached the t/s parameters that I used, along with the various curves, the box being 3.78 cubes for a pair, tuned to 33hz. Dual 4" round vents, each one a hair over 13" long.


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## wshymas (Jan 27, 2014)

This is what I have been working with. see attachment
Fs. 34.3
Qm. 9.397
VAS. 3.62
x-max (in). 0.2605
SD (cm2). 537.07
Qe. 0.4464
Re. 3.27
Le. 1.01
OHMS. 4
W RMS/ P-MAX. 350

I am running the subs harder then I should be. Opti500 2 ohm mono so about 1000 rms. also thinking about adding polyfill to my 3.2ft3 box.
Thanks for plugging the numbers in for me.


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## The Dude (Mar 24, 2007)

Glad to help. I plugged in the numbers you gave me. For a pair, high output:

2.05 cubes tuned to 44.7 hz is what BB recommends.

For a pair, high fidelity it recommends 7.4 cubes, tuned to 31hz.

I plugged in 3.2 cubes (3.74 cubes actual size, 3.2 is the internal volume less sub displacement and vent displacement), tuned to 33hz. It gave a -3db point of 49.6hz. See attached graphs for response/vv/gd curves. Slot port, dimensions as given below: 

Vent shape = rectangle
Vent ends = one flush
Hv = 5.393 in
Wv = 5.393 in
Lv = 18.23 in


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## smgreen20 (Oct 13, 2006)

Opti500 at 2 ohms will do right at 1500 wrms, so each sub will be about 750 wrms, just turn down the gain and you'll be fine. Also it is HIGHLY recommend that you put a fan on any Opti amp ran at 2ohms mono/1 ohm stereo, and that's LANZAR talking, not me.


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## wshymas (Jan 27, 2014)

That is a lot more power then I was thinking. I set the gain with a DMM about 42-43 volts.
Should I redo the gains with the higher numbers.
I do have fans to add to the amp rack. Do you know what I can expect to get out of the opti100 @ 2 ohms? I am looking at putting Infinity Kappa 60.11CS 6-3/4 components in the doors and they are rated @ 2 ohms. THANKS


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## smgreen20 (Oct 13, 2006)

2 ohms mono on all the Opti amps will come in at just about 50% more then their 4 ohm mono rating. An Opti100 will do about 300wrms at 2 ohms.


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## wshymas (Jan 27, 2014)

So I am thinking about 100-127 wrms running the opti100 in stereo @2 ohms.
Does that sound about right? Any idea what the max would be? I don't want to over power the front and rear speakers by to much. Thanks


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## smgreen20 (Oct 13, 2006)

These amps are so dead on with their numbers, 100 watts x 2 @ 2 ohms stereo. You would be correct.


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