Car subwoofer for outdoor PA use - Page 2 - diyAudio
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Old 24th August 2013, 10:13 AM   #11
dangus is offline dangus  Canada
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A lot of car subs depend on the cabin gain to fill in the low end. A pro sub tuned like a JBL SR4719 still has floor-shuddering output at 40 Hz; the 10 dB down point is 25 Hz. I don't think there's much content below 40 Hz in most music, but I haven't checked out dubstep using an RTA.

Building a couple of subs into a trailer might make more sense. You could have large flap doors that fold out to create a larger mouth.
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Old 24th August 2013, 12:23 PM   #12
FoMoCo is offline FoMoCo  United States
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Quote:
Originally Posted by Arty View Post
PA speakers are high efficiency ones.
car subs sometimes fail to even make 85 dBL, for PA 93+ is not an uncommon figure.
+1
Car subs are designed for the smallest possible box size and sacrifice efficiency to do so.
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Old 24th August 2013, 04:11 PM   #13
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Originally Posted by epa View Post
if you would use a van/truck with enough volume, you can make a serious horn in the back.
But then why not make a horn that you can just barely squeeze in and out of the van. That way you don't NEED the van as a sub. You can easily remove a PA horn and use Dolly's/casters to get the sub around outside the van after transport.

I think the only way this would make sense is if you had a system in your car with a subwoofer, and were tight on space and HAD to use the car as an "enclosure"
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Old 24th August 2013, 04:12 PM   #14
Jsixis is offline Jsixis  United States
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Originally Posted by Speedskater View Post
Also notice that those cars are good at 'thumping' but not so good at playing different musical bass notes.

^^^^^ Exactly
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Old 24th August 2013, 04:18 PM   #15
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Just a thought

Are cars really more efficient than purpose built horns?

Lets think of yourself (or the measurement mic) inside the cabin, driver seat.
Technically you're inside the "throat" of the horn, no?

Using inverse distance law, what is the SPL inside the throat of an efficient tapped horn....125db at one meter from the mouth for a PAL12 with around 500watts. Inside the throat 145+ is possible.

Or is my thinking totally off..?
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Old 24th August 2013, 07:48 PM   #16
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Quote:
Originally Posted by m R g S r View Post
1)Are cars really more efficient than purpose built horns?
2)Lets think of yourself (or the measurement mic) inside the cabin, driver seat.
Technically you're inside the "throat" of the horn, no?
3)Using inverse distance law, what is the SPL inside the throat of an efficient tapped horn....125db at one meter from the mouth for a PAL12 with around 500watts. Inside the throat 145+ is possible.
4)Or is my thinking totally off..?
1)No.
2)Technically, in a car you're generally inside a sealed enclosure, or inside a bass reflex enclosure when the windows are rolled down.
3)Throat pressures in a horn can easily exceed 145 dB.
4)Not totally .
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Old 24th August 2013, 07:54 PM   #17
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So from a practical standpoint I see no reason to do so (use the car as an enclosure)
UNLESS you can't fit a PA horn OR a BR cabinet which will produce the SPL you're looking for.
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Old 24th August 2013, 09:27 PM   #18
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Originally Posted by m R g S r View Post
So from a practical standpoint I see no reason to do so (use the car as an enclosure)
UNLESS you can't fit a PA horn OR a BR cabinet which will produce the SPL you're looking for.
Yes, that is the reason for this thread.

I'm not a DJ or anything,(although after hearing what passes for sound systems at the last few weddings I've been to, I've been tempted...) but it would be nice to have something that would work for a block party or something occasionally.

A few years ago, I had 3 LABhorns in my living room for my HT system. I sold them, and replaced them with tapped horns, so making horns wouldn't be a problem, but at 64, I'm getting too old to be lugging big cabinets around, and have no room to store them when not in use.

Seems a shame to not take advantage of the cabin gain of a car to get some extra bass without big, heavy cabinets.
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Old 24th August 2013, 09:43 PM   #19
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Seems a shame to not take advantage of the cabin gain of a car to get some extra bass without big, heavy cabinets.
The problem is that the "cabin gain", or room gain only applies to the INSIDE of the room, not outside.

Mike
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Old 24th August 2013, 09:52 PM   #20
Jsixis is offline Jsixis  United States
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Quote:
Originally Posted by Michael Bean View Post
The problem is that the "cabin gain", or room gain only applies to the INSIDE of the room, not outside.

Mike
and 2 cabs at 90lbs is a lot lighter then 1 car
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