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Imp. for automotive applications (Read 62350 times)
JimJ
Ex Member



Imp. for automotive applications
04/19/06 at 17:39:18
 
Well, curiosity's getting the better of me...

What would you guys think about an Imperial Horn in a vehicle? I drive a '94 E-150 cargo van, with nothing in back behind the two seats...currently I have a "normal" 1.5cF ported box for my e12a.22, but I'm getting the urge to do something insane for a year or two. Something like an Imperial Horn. But I have some questions...

1. Is this a horrible idea? It would be firing up in an area about 11'x6'x5'.

2. If it's not such a bad idea, what drivers would be suitable for this sort of thing? I have 1.4kW @ 2-4 ohms on tap, I'm well aware that a small fraction of that will actually be needed Wink

Thanks in advance.
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Jet-Lee
Ex Member



Re: Imp. for automotive applications
Reply #1 - 04/19/06 at 19:18:01
 
DO EET!!!!

I've pondered the idea, but always came to the same conclusion, not enough room inside a vehicle for just the enclosure. But a VAN! There's an idea.

What if you built two IMPSO's, then laid them on their sides touching at the top (what would be the top if standing upright) to make a "horn" out of the two enclosures.

mwahahaha

I need to get me van here from California. I got a '72 Econoline E-100 with a 4bbl 302 and a C-4. It's yellow with black checker racing stripes down the sides and chrome full-length side-pipes for the true dual exhaust. I love that thing.
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JimJ
Ex Member



Re: Imp. for automotive applications
Reply #2 - 04/19/06 at 23:35:48
 


That was in the SQ lanes @ MECA WV State Finals last October...I could fit an Imperial Horn and have plenty of room left over Smiley

As for subwoofers, any suggestions? Close to $300 in materials alone is going to be pretty draining on my checkbook, so I can't afford $200 each driver Cheesy

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Rap
Ex Member



Re: Imp. for automotive applications
Reply #3 - 04/20/06 at 00:15:57
 
imperial SO  ???
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JimJ
Ex Member



Re: Imp. for automotive applications
Reply #4 - 04/20/06 at 00:27:28
 
I read that thread about the SO, so really the benefit is an improved HF cutoff...so the original Horn wouldn't fare so well as a sub cabinet? Something about having the drivers exposed and inverted that I like  ;D

This isn't going to be permanently in the van, but living in an apartment doesn't lend itself to something this size Smiley Figure I'll use it mobile for a year or so until I have a place big enough to accomodate it.
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #5 - 04/20/06 at 01:44:14
 
I have considered putting my imperial in a van but I never got around to it.  The main reason is that, if I actually wanted to go anywhere the sub would have to be attached to the van somehow so it wouldn't crush me to death in an accident.  Secondly, it would turn the van into a two seater.  Then there's all that extra weight...

I imagine it would work well, the van would probably act like an extension of the horn.  If it works like I think it might, a single original version imperial would go plenty low enough and have you completely deaf in no time at all.
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J_Rock
Ex Member



Re: Imp. for automotive applications
Reply #6 - 04/20/06 at 03:20:23
 
Two laying down with the hornmouths at the ass end of the van  would be nice.  Look damn Cool, and the back doors would act like the floor of a house the imperials are in.  or upside down in the very back if you have the height.

It would look damn cool no matter what, just not sure if it would sound good or not.

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Adrian D.
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Re: Imp. for automotive applications
Reply #7 - 04/20/06 at 08:02:31
 
i don't think they'll have enough room to breathe right, but who can tell ?
i'd say some pa subs. they have decent powerhandling and nice efficiency. not sure those would go very low.
you could try 1 kicker solo x 18. it'll definetly go lower than the pa subs.
an imperial in a van would definetly hit hard.
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gexter
Ex Member



Re: Imp. for automotive applications
Reply #8 - 04/20/06 at 19:55:44
 
 Imp. for automotive applications

Thats just silly.

If some rooms are too small for an Imperial then a van?

But it might sound cool outside the van. I like the point about the beast sliding in an accident and crushing everything in its path.

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J_Rock
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Re: Imp. for automotive applications
Reply #9 - 04/20/06 at 20:23:02
 
I could go that way.  No hard feelings being killed by a Speaker.
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gexter
Ex Member



Re: Imp. for automotive applications
Reply #10 - 04/21/06 at 00:49:14
 
sound took out the walls of Jericho so an Imperial taking out a couple of bass heads is not much of a feat.

crushing sound takes on a new meaning

Works for me!
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #11 - 04/21/06 at 02:10:41
 
I'm just guessing Gex, but I think the van would act much more like an extension of the horn than a small room, I wouldn't anticipate any of the room problems the imperial experiences in a small room.  Maybe.
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Jet-Lee
Ex Member



Re: Imp. for automotive applications
Reply #12 - 04/21/06 at 14:25:59
 
DOO EET!!!!!!
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Bob
Ex Member



Re: Imp. for automotive applications
Reply #13 - 04/21/06 at 16:15:09
 
Keep the windows down, otherwise it'll blow 'em out!  ;D Cheesy

Bob
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jj420
Ex Member



Re: Imp. for automotive applications
Reply #14 - 04/23/06 at 17:45:47
 
Im not entirely certain that the confines of the van would even allow a waveform from the hornmouth to form before it started cancelling itself out, though if you mounted it facing rearwards, right behind the front seats you could get decent sound outside the van with the rear doors open.  Steve D says to mount the SO in an alcove about 8' back from your mains to allow for the length of the waves.  Likely an Imp in a van would simply compress the interior the same way as the drivers would in a standard ported enclosure.

If you did get crushed by them in an accident, you could also use them as a coffin, I think its genius, the worlds first dual usage enclosure  ???

If your back can handle it, then follow Jets advice, but be prepared to take that sucker out of there too, as it may only worsen your fuel economy.  ($1.10/L today... gawd)
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #15 - 04/23/06 at 19:46:20
 
This is almost turning into a dare...

I'd do it if I didn't have it take it right back out, but I'm not the only one with an imperial, so who is going to try it?
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Adrian D.
Ex Member



Re: Imp. for automotive applications
Reply #16 - 04/24/06 at 05:14:14
 
i'd do it, but i don't have a van, and my dad's 4x4 is too small  :(
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #17 - 04/24/06 at 05:17:35
 
I don't actually own one either, but I have access.

My main problem is that I would also have to install a head unit and wiring for an amp.
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Jet-Lee
Ex Member



Re: Imp. for automotive applications
Reply #18 - 05/05/06 at 01:03:08
 
I'm thinkin' about tackling something similar.

Someone I know want's something LOUD in his pickup. He's ready to do a full blow-through from his camper'd bed. Can the imperial be shaped differently and maintain it's characteristics, as long as the horn maintains its cross-sectional area?
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #19 - 05/05/06 at 01:26:04
 
I've already thought about it in a pickup.  The problem is that the hole through the box into the cab can't be any more than about 6 square feet, and that is if you flare it after the wheel well to use the full width available going into the cab.  That means half the box will have to be inside the cab.

Of course anything is possible and you can make a horn fit but the mouth should be at least as big as the imperial for adequate lf extension.  In a regular pickup the last and largest part of the horn flare will have to be inside the cab.

If you can chop the whole back of the truck out, that changes everything and you can get the 9 foot mouth without extending the box into the truck.  This will probably destroy the structural integrity of the vehicle.

Anyway, the hole between the box and cab is going to be the important factor.  And I would hold off until one of us gets off our lazy butt and find out what a big horn is going to do in a van.
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #20 - 05/05/06 at 01:39:30
 
If you are willing to cheat a bit there are ways to decrease the size of the horn, namely chopping the last part of the horn off.  

This works in a tractrix expansion which is also the most efficient (in terms of box material and overall size).  Since the last section of the horn is the largest, chopping off a couple of feet can save a huge amount of space and wood.

The side effect is ripple in the upper range of frequencies the horn is playing, similar to tl ripple in the frequency response.  But if you can effectively cut half the size and weight of the box this may be a road you wish to travel.  There are other designs readily available that have the same mouth size of the imperial but are reported to play about an octave lower by shortening the length of the horn.

I think that a big horn firing into a small area (vehicle cab) will behave like an extension of the horn, or at least in the case of the truck cab, a tuned enclosure.  In this case, it should be like sitting in the mouth of a horn.  But is Gex is right and the cab behaves like a really really small room there would be no reason to go ahead with this.

If you need more info on horn theory, just ask, I have lots and so does just about everybody else here.
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Jet-Lee
Ex Member



Re: Imp. for automotive applications
Reply #21 - 05/05/06 at 01:54:06
 
The idea is to take out the entire back wall of the cab, seal it to the camper shell, and re-brace the outer sides similar to a roll-cage.

Basically making it into a van.
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #22 - 05/05/06 at 01:55:42
 
It should fit very nicely with no modification in that case.
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Jet-Lee
Ex Member



Re: Imp. for automotive applications
Reply #23 - 05/05/06 at 02:00:49
 
I was just thinking about re-shaping it to make it a little lower profile, so maybe two can be put side by side and the cones and horn are more direct.

It's an SPL concept.
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #24 - 05/05/06 at 02:02:03
 
If the vehicle is really tight, you could really go overboard on this without much materials.  If you think of the van to be the enclosure itself, you can make a horn by placing a wedge shaped sealed box at the right spot inside the van.  I don't know if you get what I'm saying but it would take a bit to explain properly.  And I can't draw.
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #25 - 05/05/06 at 02:16:11
 
A different idea if this is for pure SPL is to design your own horn.  It's easier than you think.  Maybe model a 20 hz horn and then cut the last 10 feet off.  It's still going to be almost 15 feet long but the expansion rate is slow, so it doesn't get big fast.  Sensitivity should be quite a bit better than the imperial because of the length (at least twice as long) but the frequency response is going to be bad.  But all you have to do is target your peaks to the measured competition frequency.  Make all your friends deaf with an 8 inch driver.
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Bob
Ex Member



Re: Imp. for automotive applications
Reply #26 - 05/05/06 at 12:07:31
 
Why not turn a small box truck/moving van into a rolling IB?
Mount the drivers in a weatherproof enclosure on top of vehicle, like an RV A/C unit.

Bob
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Adrian D.
Ex Member



Re: Imp. for automotive applications
Reply #27 - 05/05/06 at 13:18:16
 
something like this ?
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Bob
Ex Member



Re: Imp. for automotive applications
Reply #28 - 05/05/06 at 13:41:00
 
Thanks Adrian, Yes, but substitute A/C unit for a IB enclosure.  :-/

May need some wicked caps & power conditioners to tame down that generator.

I just sent that to all my car buddies.   Cheesy

Bob
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Jet-Lee
Ex Member



Re: Imp. for automotive applications
Reply #29 - 05/05/06 at 20:44:14
 
[quote author=bassboy  link=1145468358/15#24 date=1146790923]If the vehicle is really tight, you could really go overboard on this without much materials.  If you think of the van to be the enclosure itself, you can make a horn by placing a wedge shaped sealed box at the right spot inside the van.  I don't know if you get what I'm saying but it would take a bit to explain properly.  And I can't draw. [/quote]
I understand what you're saying, and now you would not believe what I just drew out by hand. This is a serious concept I have here.

I just need someone to model it for me, as I have NO clue how.
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John in CR
Ex Member



Re: Imp. for automotive applications
Reply #30 - 05/05/06 at 21:20:19
 
Don't waste your wood and time.   There's not enough air volume for the wave to fully develop into a wave, so much of it will just stay as a pressure front not a sound wave.  A horn needs to couple to the environment it is in to function properly.  In this case there will be much more audible bass outside the van than inside.  With the tremendous cabin gain inside a vehicle, there are much easier and smaller ways to get big bass in a car.  A single high excursion 12" or 15" can give you more bass than your ears can handle in a well designed BR.  If all you want to do is ride around disturbing the neighborhood, then go for it.  If someone shoots you, at least you'll know why.
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Jet-Lee
Ex Member



Re: Imp. for automotive applications
Reply #31 - 05/05/06 at 21:22:22
 
Horn Segments
Cross-sectional Area

Length = 109.675in (11.056ft)
Throat = 245in^2 (1.7ft^2)
Mouth = 1656in^2 (11.5ft^2)


S1
length = 21in
throat = 245in^2
mouth = 720in^2

S2
length = 37.675in
throat = 720in^2
mouth = 1152in^2

S3
length = 51in
throat = 1152in^2
mouth = 1656in^2

Using two of these(sharing ~15ft^3):
Quote:
Specifications:
This woofer is designed to work best in the following enclosures:

A small, sealed enclosure with an internal volume of 1.25 cubic feet (1.25-1.75 cu/ft acceptable)
A ported enclosure with an internal volume of 2.0 cubic feet (1.5-2.0 cu/ft acceptable) with a 4" diameter x 10.75" long port
RFP4412 Size 12 inch Type Woofer Voice coil Configuration
Single Material
Aluminum Description
2.5 4-Layer Cone Material Paper
FIBERlock Frame Material Frame
Stamped Material
Steel Surround Material Foam Description

BART Spider Crossover Specifications:
Power handling(RMS) - 200 Watts
Power handling(Peak) - 400 Watts
Impedance - 4 Ohms
Sensitivity - 88 db
Vas - 3.05
Fs - 28
Qes - .510
Qms - 6.237
Qts - .472
Xmax - 12.954
Revc - 3.69
Levc - 4.48

Dimensions:
Depth Bottom mount - 5.8125 in.
Cutout - 11.125 in.
Displacement - 146.88 cu in.

Enclosure:
Sealed box:
Recommended volume - 1.25(Cubic Feet), 35.40(Liters)
Ported box - Recommended volume - 2.00(Cubic Feet), 56.64(Liters)


This is just a quick sketch with somewhat rounded numbers.

Would it do anything?? Methinks not, but curious none-the-less.
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #32 - 05/05/06 at 22:21:37
 
This is all just meaningless speculation until we find out how a large horn works in a very small enclosure.  John may be very right about the horn needing a relatively large area to couple to.  I would not be inclined to argue with him unless I tried and got favorable results with the imperial in a van.

Jet - I am not using hornresp to model horns.  I use the tractrix calculator or exponential calculator on the single driver website for a quick and dirty idea of what the horn is going to look like.  All you need to know is the throat area and lowest frequency desired.  Model in eighth space (corner loading) and it will numerically plot the horn flare in about 5 seconds.
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #33 - 05/05/06 at 22:30:10
 
Hornresp is a more versatile tool, as you can model whatever you want.  The horn flare calculators will only show you the ideal expansion for ideal response.  If you stray from the plan the results are unpredictable.  Hornresp can take these deviations into consideration but it is a much more cumbersome and slow process.  (But probably worth it in the later stages of design)
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Jet-Lee
Ex Member



Re: Imp. for automotive applications
Reply #34 - 05/05/06 at 23:27:23
 
I didn't know there was anything other than HornResp, and it's like greek to me (I think I understand Greek better).

Where's this tractrix calculator?
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #35 - 05/06/06 at 02:13:52
 
Start here.

http://melhuish.org/audio/horn.html

Read the whole horn section and the calculators are the last things in the section you need.  You can check the last pages in the section but they are just driver specific recommendations.

You only input 4 parameters, but it's metric.  Throat area, flare frequency (lowest effective frequency), size factor (8 for cornerhorn), and desired width of cabinet.

It outputs 4 columns of information.  The only ones I look at are distance from throat (length) and area, which is the cross sectional area.

This is the fastest and easiest way to model an ideal expansion rate.  (Remember that variations from the plotted design are at your own risk.  This makes no accomodations for shortened horns, hard bends or inaccuracies within the horn, bad room placement, etc., hornresp is better for that)

Use the theory you read on the previous few pages to design a loading scheme to couple to the throat.

If you want more good sources, just ask, I got lots of good articles on theory.
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Steve Deckert
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*****


If the 1st watt
sucks why continue?

Posts: 6234
Re: Imp. for automotive applications
Reply #36 - 05/06/06 at 14:26:35
 
The only way any Imperial is going to work in a van is if you cut the floor of the van out and fire the entire enclosure down onto the street.
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bassboy
Ex Member



Re: Imp. for automotive applications
Reply #37 - 05/06/06 at 16:34:21
 
Well it looks like Gex was right all along and I was wrong again (I kinda thought it was gonna work).  But it saved me the work of actually trying it out, so even if I'm wrong I'm still happy.

Stick to the WO and be happy, it's more than enough for me, anyway.  (In a vehicle)

Don't give up on the horn theory though, Jet, one more trick up your sleeve isn't going to hurt, just leave the big horns in the house.
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Jet-Lee
Ex Member



Re: Imp. for automotive applications
Reply #38 - 05/07/06 at 03:15:58
 
I respect Steve's post, but am still going to make an attempt, at some point.

I'm one of those people that touches the stove after being to it's hot. I learn from experience, not example.
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gexter
Ex Member



Re: Imp. for automotive applications
Reply #39 - 05/08/06 at 02:31:59
 
It depends on how many times you touch a hot stove before you learn!
third degree burns are not for everyone.

heh heh could not resist. Smiley Smiley Smiley Smiley Smiley Smiley Smiley Smiley Smiley Smiley Smiley Smiley Smiley Smiley

pulling your leg Jet!  :)
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DaveCan
Ex Member



Re: Imp. for automotive applications
Reply #40 - 05/08/06 at 06:15:22
 
 Why not just put a motor and some wheels on an Imperial?, now that would be something  ;D   Dave Smiley
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Jet-Lee
Ex Member



Re: Imp. for automotive applications
Reply #41 - 05/08/06 at 06:17:36
 
[quote author=gexter  link=1145468358/30#39 date=1147051919]It depends on how many times you touch a hot stove before you learn!
third degree burns are not for everyone.
:) [/quote]
I dunno. I've lost quite a few hairs. I made $20 walking barefoot across a fire in shorts, at Pismo. Some of the hair is still missing after 2 years.
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60ndown
Ex Member



Re: Imp. for automotive applications
Reply #42 - 05/08/06 at 14:52:34
 
[quote author=Jet-Lee  link=1145468358/30#41 date=1147065456]
I dunno. I've lost quite a few hairs. I made $20 walking barefoot across a fire in shorts, at Pismo. Some of the hair is still missing after 2 years. [/quote]

$20 for an injury you can still identify 2 years later? and i thought you were smart jet Roll Eyes  was alcohol involved Grin
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Jet-Lee
Ex Member



Re: Imp. for automotive applications
Reply #43 - 05/08/06 at 15:16:53
 
[quote author=60ndown  link=1145468358/30#42 date=1147096354]

$20 for an injury you can still identify 2 years later? and i thought you were smart jet Roll Eyes  was alcohol involved Grin [/quote]
The $20 was just a bonus, I do it anyways. Embarrassed

Oh yes, alcohol had a BIG role in it! Cheesy

Anyone got $20? I'm goin' campin' this weekend. Kiss
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gexter
Ex Member



Re: Imp. for automotive applications
Reply #44 - 05/09/06 at 00:37:27
 
LOL
your a true adventurer Jet. and the scars to prove it. Smiley
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60ndown
Ex Member



Re: Imp. for automotive applications
Reply #45 - 05/09/06 at 00:37:30
 
[quote author=Jet-Lee  link=1145468358/30#43 date=1147097813]
The $20 was just a bonus, I do it anyways. Embarrassed

Oh yes, alcohol had a BIG role in it! Cheesy

Anyone got $20? I'm goin' campin' this weekend. Kiss [/quote]



whats the last thing a 'redneck' sais before he dies?



"hey everyone............................watch this"
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gexter
Ex Member



Re: Imp. for automotive applications
Reply #46 - 05/09/06 at 12:04:25
 
LOL very true..
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Valiant_ap6
Ex Member



Re: Imp. for automotive applications
Reply #47 - 05/10/06 at 00:04:22
 
Hey, has anyone dragged an Imperial into a bathroom,
or large closet and had a play?   ??? They'd be the approx
volume of a van. (Similar acoustic surfaces too). I'd try
it, but the Imperials are safely in Jake's hands now. I don't
think my wife would have appreaciated this venture into scientific research anyhow..."Yes Virginia, there is a limit!"

Gaz
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Lee in Arkansas
Ex Member



Re: Imp. for automotive applications
Reply #48 - 05/22/06 at 12:38:41
 
That's a good point, Valiant. I guess I could build one and put it in the living room of my apartment, seeing as it's about the same size. Cry

I guess what I'm trying to experiment with is this:

The imperial puts out great bass (from what I've read). Bass is what's used in SPL competition. Now, my Escort(wat too small for an Imp variation) peaks with a 52hz wave. This is in the range of an Imperial, correct? So, why not put an Imperial(or two) into a van, that has been re-inforced to eliminate as much panel resonance as possible, and play the lower tones that can peak in the larger vehicle.

I just don't understand why it couldn't work if these low tones are already used in smaller vehicles with success(I got the trophy to prove it).
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jj420
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Re: Imp. for automotive applications
Reply #49 - 05/28/06 at 18:47:07
 
Im not sure i have the right words for this, but think abut it like a hose in your yard.  The Imp. is the hose in this example, more like a fire hose.  Fire that sucker out into your yard, and youd have it watered in no time, but by no means would you immediately innundate your entire yard.  Now, take that puppy inside, all the way upstairs to the master bathroom.  Crack the valve and your bathroom is not only inundated immediately, but also filling quickly.  In your escort, a nice quick watering could be had from a standard hose, (your existing setup, no offense,) and a fire hose (Imp.) would fill it to the brim very quickly indeed.

In too small of a space, the cone ends up compressing the air, rather than making waves in it, a horn would experience the same thing.  Just as the water in your bathroom would no longer stream once the nozzle was immersed, the cone could not create pressure waves in the atmosphere of the vehicle.  Under those sorts of pressures, interesting things start happening to both the vehicle and the speaker, thats why Steve said it would only work if the horn fired out of the vehicle, not into it, because the Imperial is too big a hose for the bathroom your watering... or something like that...

I gotta drink less coffee before lunch...

JJ
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