15hz, high volume

[freddi]

re: Audiopipe 18 - good specs - if this is his model Audiopipe TXX-BD2W-18 User Manual (Page 5 of 8)

 

[Rademakers]

Hmm...This should get you started. Personally I would aim at 130 dB/m, which should be within the excursion capabilities of this driver.

 

[GM]

re: Audiopipe 18 - good specs - if this is his model

So-so if accurate, but Fs, Vas much too high to max out in the desired ~14-42 Hz BW, but if it's all we've got to work with.........

GM

 

[cbdb]

In a car? Lol. You will not hear any of the 15 hz, all the resonant vibrations will completely drown that out and turn your bass into a joke.

 

[freddi]

@Rademakers - that looks good - pretty big - wonder if it would fit the OP's car/truck/whatever ? A few more details would be helpful - like purpose, driver model ...

 

[Andrew Eckhardt]

Just vent to free air in the truck bed. Measure cab response and Linkwitz Transform to taste. 4 mid Q 18s should do pretty well.

 

[Etocynned]

Right sub but its a D2 and the specs are a bit different...ill see if i can find a screengrab of the page.
Ya 140db in car.

Hmm...the tapped horn sim looks cool about what id thought.

 

[scottjoplin]

"140dB Threshold of pain, all frequencies
140dB Hearing protection required (definite long term damage)"

 

[6L6]

Ya 140db in car.

STOP. You are talking about levels that are instantly damaging to the hearing of any occupant of that vehicle, and well as those nearby.

Look for your information somewhere else. This site will not be party to you injuring yourself.

 

[cowanaudio]

It's telling to close the door on a car while looking at the display of a flat reading SPL meter. 140dB SPL at low frequencies is easy. How about diving into water? Much higher. It's all about the frequency. Very high amplitudes at low frequencies are common in daily life. I've personally experienced above 150dB, flat weighted, in a car between 15 and 25Hz. You could easily hear the person next to you speak at a normal level, you just couldn't understand them due to huge modulation of their chest cavity and I guess the ears.

I would not expose my ears to 105dB in the mid band for more than a few minutes.

 

[cowanaudio]

"140dB Threshold of pain, all frequencies
140dB Hearing protection required (definite long term damage)"

"A" weighted I absolutely agree. The OP wants 140dB flat weighted. Completly different story. I don't have the FM curves with me but from memory this would be around 50dB above the threshold of hearing. Not all that loud. Opening the back window on your car at 100kph will get you WAY louder, and lower.

 

[cowanaudio]

It should probably be noted that the presence of high levels of low frequencies actually has a protective effect on human hearing. The ears response is to close down the ear canals, with no damage is done to the cilia. I used this effect to advantage in a recent nightclub installation. The solid bottom end made for a very exciting experience at levels that posed no risk to the patrons hearing.

 

[GM]

Hmm...This should get you started. Personally I would aim at 130 dB/m, which should be within the excursion capabilities of this driver.

FWIW, at down to 14 Hz I could only 'squeeze' ~127 dB [avg]/0.5pi/90 W out of a ~55 ft^3 net DSL concept TH and still get a usable ~ 1.5 octaves, though maybe one of those higher order TP/TH alignments can eek out a few more dB.

GM

 

[BP1Fanatic]

Go to post #141.

the HouseWrecker. 11hz Twin CVX-15 Tapped Horn - Page 5 - AVS Forum | Home Theater Discussions And Reviews

 

[GM]

This one? I had to search to find it on pg. 8, post 221 of 422. Lately, this happens with every link from here to AVS : https://www.avsforum.com/forum/attachment.php?attachmentid=8298&d=1338330165

GM

edit: just noticed this is a single driver.........found this dual TH sim as pdf in post #1: https://www.avsforum.com/forum/attachment.php?attachmentid=10511&d=1338336683

 

[BP1Fanatic]

I think those 2 TH's are for the house. The TH on post #141 is for a pickup bed. Instead of 4 subs, build it for 2 subs to lower the tuning.

 

[BP1Fanatic]

Hey GM, the wife and son are headed to Norcross, Ga tomorrow. Her parents live there.

 

[Etocynned]

I wouldnt expose myself to over 120db above 60 hz for more than 1 minute intentinally. Below that the FM curves show a rolloff of about 18db/octave in sensitivity.

 

[Circlomanen]

Im understanding Hoffman so im expecting large enclosures and large amounts of power. I currently have 2300w on tap i to the 1Ω load my driver has nominally.

though maybe one of those higher order TP/TH alignments can eek out a few more dB

4 ALPINE R-W12D2 in a 3 cubic meter ROAR will comfortably hit 140 dB @ 14 Hz in a 0,5 pi environment. If your car cabin is structurally strong and stiff enough you will get upward of 10 dB cabin gain on top of this.

The downside might be the 3000 liter box....

 

[Circlomanen]

Some more data.

The max spl graph in the previous post was calculated with 2300 watts and 20 mm xmax. ( Considering the tactile and very physical characteristic of the flat plane wavefront from the large front resonator this would be a contender for any "brown note" experiments)