2 DC Lvl 4XL's in a Horn -- Experiment

Designing a enclosure for two DC Lvl4 XL's with LVL 5 softparts was quite a challenge... The guinea pig for this experiment desired a strong response into the 20's, and "violent" response in the low 30's from his two 12's and about 6k RMS in a 2007 Nissan Sentra .... I ended up at a 6.0cu ft rear-loading horn for these subs with a particular anomoly that occures during the expansion of the throat of the horn. The blueprints will be posted, but without dimensions.

It won't work right until the enclosure is sealed from the trunk where only the front is firing into the cabin ... But, here's the build pics so far. He should have it done in a few days. Numbers to be posted soon I'm hoping...

Just from me looking at it, I don't see how the internal volume is 6 cubes, but I would image at certain frequency ranges it is going to sound like those sub are going to explode, how long is that port going to turn out, your final frequency is going to be 20 hZ? Why so low? I am curious for your findings and results.....

that should be loud as shit

AMI CUSTOMS wrote:

Just from me looking at it, I don't see how the internal volume is 6 cubes, but I would image at certain frequency ranges it is going to sound like those sub are going to explode, how long is that port going to turn out, your final frequency is going to be 20 hZ? Why so low? I am curious for your findings and results.....

The total system is 6cu ft. The compression chamber inside the box is not 6cu.ft, it does not need to be. It is infact, very small. About 0.17cubes. It's utilizing the compression in the throat of the horn that makes it work the way it does. If you view it as a ported enclosure, which it is, but is not, it could be seen as a ported enclosure that is tuned to 26hz with a port that is technically 103inches long, but acoustically ~109inches long. The final frequency isnt 20hz, but we wanted extension into that frequency range. The roll off frequency for this project should be ~28hz. Cabin gain will take up the rest of the extension, down to about 22hz, until losses set in from panel flex and window flex. It shouldn't be able to touch the teens, but I'd like to see if it does.

still looks loud lol

Oh its supposed to be ...

We'll see how right I am by my calculations if it meters around 147 between 33 - 36hz, and a 142 at 27hz. ... ~146 again at 45hz...

Loud and low .... that's how I like it too...

I remember seeing a video of an enclosure on youtube that housed two SSA Icon 10's, metering a 141db at 10hz and 143ish at 20hz.... I'm still pretty damn confused as to how that was happening with only 1100 watts I believe...

any new pics?

yea we want pics...............

He should have some for me to upload later tonight ... I hope so too... He's gonna try to be finished with it by either this tuesday or the next, but will not be able to get it metered until june 12th....

what car is this goin in ?

2007 Nissan Maxima

Outfitted with a 270amp HO alternator and 2 Crunch 3000w monoblocks and an extra battery if I'm not mistaken.

ssweet will it be at any of the shows?

i too would like to hear it

i thought horn boxes the port start small then get big

Yes, most horn loaded enclosures do. Infact, this one does as well, if you can see it.

We made a slight modification in terms of the throat size, so it looks a wee bit different than the original prints...

And no, this car will not be at any Arkansan shows unless he decides to drive down from Ohio. (Which would be sweet really...I'll ask him if he wants to make an appearance... he can get it metered sooner than freaking June 12th, lol)

Anyways, pics! ... But with the cellphone, so they seem a little weird (where the wood looks warped, it really isnt, thats the lens)

U missing one piece? Picture has three box only two

He took the pics before the third piece was inserted... Lol...



Edit: God I hope he inserted the third piece. lmfao....

looks loud just sitting there

It wasnt maximized for total just "earbusting" loudness, but it could have easily been a few tweaks of the throat size and it could've easily made this an SPL machine.

I'm itchen to see how accurate my calculations were, vs. real world results... It's driving me crazy lol...

He's finished with it, but hasn't uploaded pics ... Nor gave me a subjective review yet ... I'm so anxious



The grey line shows the output (I forgot how much power was being simulated for this graph... but anyways) ... in far field response, without the effects of the cabin. This is theoretically how it would meter on flat ground with no buildings or anything within 20 or 30 ft. Of course, we all know the near "magical" transformation that occurs to the sound when the box is dropped into the cabin; Essentially louder and lower, we can see that since the roll off of this horn is about 27hz without cabin gain, it's a pretty safe assumption that it should hit lows quite well... and cabin gain will fill in the notch that occurs in the response curve to give a very well balanced sound. hooray for SQL.

The green line, however, is a slightly modified version of the throat expansion to give an SPL monster. As you can see, its nearly a 10db gain at the vehicle's resonance frequency (48hz) on the exact same amount of power as the original horn. Peak theoretical output for the SPL box is about 154db with about 6000w max power input... not bad for 2 12's.

Well the subjective review is in ...

Jeff writes ...

Quote :

okay.. this is what i can tell you about your box at approximately less than 2000 watts rms...my ears hurt.

got huge pressure change and a pop with all windows sealed up.. ow

Vids to come later tonight or tomarrow ...

cant wait to see the video too bad its not as good as being in it

Yea ... I'd love to sit in it myself... I told him to come on down ... It's only a 13 hour drive ...

only 13 if he leaves now and gets here to sleep he'll be ready for sunday in hot springs

Thats "exactly" what I told him .....