Loudspeaker 4 or 8 Ohm?

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astaib
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Loudspeaker 4 or 8 Ohm?

Post by astaib »

Hello,

I need to change my Loudspeaker because mine is dead and the air is leaking inside because of it...

I just unscrew it and read on the back that it is a 4 ohm.
But on the illustrated part catalog, I read 8 ohm?

What will be the difference?

Shall I re install a 4 ohm just like the original one or follow that IPC?

Thank you.

Arnaud.
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Steve
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Re: Loudspeaker 4 or 8 Ohm?

Post by Steve »

Mine was a 4 ohm. I replaced it with a 4 ohm. Don't buy it from Diamond. Much cheaper from an electronics supply house.
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Rich
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Re: Loudspeaker 4 or 8 Ohm?

Post by Rich »

The IPC isn't always informative. The equipment list furnished by Diamond for my plane shows it as a Visaton FRS8/4 ohm speaker. These are really cheap from various sources.

BTW, mine has a similar problem. Can this speaker somehow be R&R'd from inside the plane or does a GPS antenna need to be removed to do so?
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Re: Loudspeaker 4 or 8 Ohm?

Post by astaib »

My idea was to go through the map lights and I read that this is the way.

The left seat map light need to be repair, I will start by removing this one and I hope that I won’t need to remove the right seat map light too.

And of course I found it on amazon for 10€!

Arnaud.
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Steve
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Re: Loudspeaker 4 or 8 Ohm?

Post by Steve »

Rich wrote:BTW, mine has a similar problem. Can this speaker somehow be R&R'd from inside the plane or does a GPS antenna need to be removed to do so?
It can be R&R from inside. A couple of the nuts are tough to get to. I used this:

https://www.lowes.com/pd/Kobalt-Metric- ... ch/3387676

which made the job much easier. You will also have to desolder the wires from the speaker going to the connector and solder to the new speaker.

Steve
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Re: Loudspeaker 4 or 8 Ohm?

Post by astaib »

Hi steve,

The map-light are in place only with silicon isn't it?

The speaker seem to be held only with the 4 screws.

What for is the wrench?

Thank you for your help.

Arnaud.
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Re: Loudspeaker 4 or 8 Ohm?

Post by Steve »

Arnaud:

Correct, the map light assemblies are secured with adhesive and spring clips. At least on my aircraft, the speaker grill is held in by the 4 screws. There are studs in the interior of the plenum which secure the speaker. The wrench I referenced is useful in removing the nuts on those studs, since there is very little clearance in the plenum due to the sheet metal assembly used for grounding.

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Re: Loudspeaker 4 or 8 Ohm?

Post by Rick »

I believe the reason the speaker blows out is because the area above the speaker is pressurized by the air flowing into the vent under the pilot-side wing root, which feeds into the hollow area in the ceiling (as well as the rear-seat vents). During cruise, the air pressure in this area is what flows out of the ceiling vents and rear-seat vents. The speaker also sits between this pressurized area and the cabin, so the fragile speaker paper tends to tear easily to let the air escape.

My solution was to cut a piece of heavy plastic to match the shape of the black speaker cover, and place it between the cover and the roof to act as the pressure barrier instead of the speaker cone. So far, my 2nd speaker is still in tact. I was thinking you could replace the speaker without removing a map light (i.e. by just removing the 4 speaker cover screws), but it's been a long time and I may be incorrect.

The map lights are held in by a clip at one end that snaps over the lip of the hole to hold them in. Without the calking, you will notice lots of air bleeds around them, too, from the same cavity! The calking also seems to add some support to hold them in.
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Re: Loudspeaker 4 or 8 Ohm?

Post by astaib »

Hi Steve,

When I remove the grill with the 4 screws the speaker is completely free and seems to be removable without unlocking something else, then can you confirm that if I remove the map light, I can "slide" it though the hole of the map light? You are talking about studs, but I don't see them. Other question, are the spring clips easy to remove when I will have remove the adhesive?

Hi Rick,

I will change the speaker (if not to difficult!) and then I will install a heavy plastic piece, what do you suggest as thickness? Is it hard or soft plastic?
Is it still possible to hear the speaker when this plastic part is installed?

Thank you again guys.

Arnaud.
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Re: Loudspeaker 4 or 8 Ohm?

Post by Rick »

The retaining clip I was referring to can be seen on the right end of the map light assembly in this picture - actually, it's more of a spring than a retaining clip:
Map Light (left side).jpg
Basically, if you remove the calking and then pull down on the end of the map light where the switch is, it should "pop" out. You don't need to remove the clip - it is attached to the fixture and is just a spring. The other end (where the bulb is) has protrusion that catches on the lip of the hole, and then the clip keeps pressure on the other end to hold it in.

Yes, if you remove the map light, you can slide the speaker over and remove it through the map light hole. I couldn't remember if the speaker was inside or outside once you removed the speaker cover.

As far as the plastic I used, I believe I cut it from a piece of laminating material, so it was probably 5 mil or 7 mil, thin and flexible, not anything solid. The plastic needs to sit tight against the bulkhead to form an air-tight seal. I have no problem hearing the speaker - in fact, it's a bit loud on the ground!
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