Indoor Theater Sound repplication for a Drive-in.

[eriojas]

ThomasW,

Since you have probably answered every imaginable question every posed about IB subs (including mine many years ago) I would like to throw a this out there from behind the bleacher for you analysis. Feel free to delete if not suitable but I think due to its’ oddness it will peak some interest.

Problem: How to only recreate as best as possible the low tones (explosions) of an indoor movie theater in a drive-in theater environment through the use of either current and/or near future technologies.

Constraints: Reasonably plausible
Cost effective
Electrically reasonable


Hyposensitize this: 150 quality, yet inexpensive, PC subwoofers with a response range of 25hrz – 80hrz that are activated remotely during a movie sound track. Each would be located somewhat evenly, powered by the batteries of cars attending. What is the hypothetical outcome of such a system? What should the optimal response range of the subs be? What would be a reasonable speaker wattage. Would there be an optimal speaker placement or speaker facing direction for outside placement the car? How about in-car placement? What other issues need to be addressed beside the neighbors? Am I off my rocker?

What other setups could solve the problem? Anyone?

[ThomasW]

As I see it there are 2 options, buttkickers (tactile transducers) for every car or a 18" sub for every car. Your choice. Neither will run long off a battery.

[eriojas]

Buttkickers were considered but it would have to be anchored to the car and that could cause something important on the car to vibrate loose or maybe even activate the airbag. 18' woofers, well not pratical power wise as mentioned. The problem is to get as close as practical to replicating indoor theater lows outdoors. How close would you consider practical replication at: 80% 50% 30% 20% or that of an indoor theater. Where would you say a nomal car's speaker are currently at replication an indoor theater's lows: 10% 5% 2%?

[ThomasW]

I think you misunderstood my first post, it was satirical.

The proposition of trying to reproduce any aspect of HT sound with a portable system that can be temporarily place in a car is totally unrealistic.

[chrisbee]

I think you are fixating too much on doing iit all outside the vehicle.

Why not just have cheap active tubular, ported, car sub enclosures on armoured cables to go on the back seat or floor of the cars during movies? Fine wire mesh to protect the drivers and ports from the usual idiots.

The car itself will add all the LF gain you could hope for. You will have to supply mains voltage to each active sub though.

Security againts theft would be your problem. What about subs handed out on arrival against purchase of a ticket and retrieved again on leaving through a lift-up barrier?

Costs could be kept low by using bare cardboard tubes (or PVC pipe for better waterproofing) with cheap drivers. Amps could be standardised with no controls.

Or the whole system could run on high impedance with passive plug-in subs and remote specialised power amps.

[eriojas]

admin said:

The proposition of trying to reproduce any aspect of HT sound with a portable system that can be temporarily place in a car is totally unrealistic.

I agree is unrealistic but only on the grounds of those who think strictly inside the box. But IB thinking all about being outside being box, is it not? ;D It's an interesting concept because it's not realistic, yet.

Chrisbee,

Inside or outside the car does not matter as long as some reproduction is there. I see the #1 main is power consumption and 2nd may be finding a drive-in theater.

A deposit would alleviate theft. Maybe this setup could be used as an additional rental revenue stream for a drive-in, but thats off-topic.

Any more outside the box opinions out there?

[chrisbee]

Further rambling:

If you really want external subs you could use drop-in PVC parking posts as sub enclosures. Have them capped against the rain and slotted or ported at car window level to maximise bass output for least investment in watts. Use a flexible umbilical reflex port for those colder nights? ;D

If you start reproducing serious quantities of bass out of doors then you had better be a very long way from civilisation and have a lot of power available.

I think you missed my point about cabin gain. It offers virtually free bass for quite a small investment per vehicle.
Otherwise there wouldn't be such a large market for inferior products with even worse sound quality.

Have you considered using their cigarette lighter sockets to power those active subs at their expense? A 12 Volt digital amp will make the most of those tired batteries for least power consumption. ;D

Charge extra for bump starting their cars if they completely drain their batteries.

[twisterz]

I don't know where you live but here in Northern California the Drive-ins broadcast on an FM radio Fz into your car stereo.