Overhead Speaker

[floatplaneflyer]

Bought a replacement speaker online, it was an exact match to original, replaced light with a new led fixture for $15 bucks, love it!

Yes, inquiring minds want to know. Pictures please! and cost if you can!

-Harmon

[ghostflyer]

Regarding the speaker, it’s my belief that the original had a strange impedance. I purchased mine off Tandy up in big bear ,California . They had a closing down sale and it was in a parts bin for a dollar. This was about 7 years ago.

[170C]

I all did a lot of business with Radio Shack/Tandy Corporation "in the day". Hated to see that business go away. Charles Tandy must have rolled over in his grave when the company went under.

[GAHorn]

Regarding the speaker, it’s my belief that the original had a strange impedance. I purchased mine off Tandy up in big bear ,California . They had a closing down sale and it was in a parts bin for a dollar. This was about 7 years ago.

I seem to recall the same... I think 8 -Ohms was common and the OEM was 4 Ohms... but. I’ve slept since then.

[Bruce Fenstermacher]

I seem to recall the same... I think 8 -Ohms was common and the OEM was 4 Ohms... but. I’ve slept since then.

I remember the same George.

What is important today is that speaker expedience match what ever amp is driving it today. I would wonder what the current amp requires.

[gfeher]

It depends on the audio output of the audio amp of your particular radio (if it has one) or your audio panel (if you have one and it has an audio amp). But 4 ohms is pretty common for 12V/13.75VDC systems. For example, a Bendix-King KX-155 with the optional internal audio amp has a 4 ohm audio output from the amp. Like George and Bruce, my guess is that the original speaker was 4 ohms. That's what's in my plane, as I have a KX-155 with an internal audio amp (although who knows if it's the original speaker).

[GAHorn]

All this agreement is making me suspicious.....

[floatplaneflyer]

Regarding the speaker, it’s my belief that the original had a strange impedance. I purchased mine off Tandy up in big bear ,California . They had a closing down sale and it was in a parts bin for a dollar. This was about 7 years ago.

8 Ohm I believe.

[gfeher]

I believe that those Jensen Concert speakers came in both 4 ohm and 8 ohm versions. If you know the audio amp output of your radio, that would give you a better idea of whether it's a 4 ohm or 8 ohm speaker.

[floatplaneflyer]

I seem to recall the same... I think 8 -Ohms was common and the OEM was 4 Ohms... but. I’ve slept since then.

OK so you can run an 8 Ohm speaker on a tap for a 4 Ohm, but not necessarily the reverse. I was told the original was 8 Ohm, so that's what I requested at the reconing service.

-Harmon

[GAHorn]

If you have a radio with an audio amp designed for 4 ohms and you install an 8 ohm speaker, you may find that you don’t have enough VOLUME to hear over the engine noise. Otherwise, you should have no problem. But if you install a 4 ohm speaker paired to an 8 ohm amplifier output you might blow the amplifier.

(I used to win a lot of marital arguments.... until she discovered Google):

When you talk about whether an audio loudspeaker is 4 ohm or 8 ohm, you're referring to the speaker's impedance, an electrical property similar to resistance. Speakers come in several different impedance ratings; matching the impedance of your speakers to your amplifier ensures that your audio system will run efficiently and sound its best.
About Impedance

Like resistance, impedance is a restriction of the flow of electrical current in a circuit. Resistance and impedance are similar, although impedance changes for different audio frequencies and resistance is generally constant. Impedance comes from the interaction of the speaker's voice coil and other electronic components. A speaker's impedance rating is an average taken over a wide range of audible frequencies.

4 Ohm Vs. 8 Ohm

A 4-ohm speaker requires more power from an amplifier than an 8-ohm speaker to produce the same loudness of sound. This is due to the relationship between voltage, current and resistance in electronic circuits; for a given voltage, a lower impedance means a greater current. Power is a combination of voltage and current, so to provide more current to the speaker, an amplifier must have a higher power rating.
Series and Parallel Connections

When you connect two or more speakers to the same amplifier output, you change the total impedance of the speaker set. You can wire speakers in series or parallel; a series arrangement has the "hot" wire of one connected to the "ground" wire of the next, whereas a parallel wiring connects the "hot" wire of one speaker to the "hot" of the next, and "ground" of one to the "ground" of the other. Speakers connected in a series arrangement combine their impedance; for example, two 4-ohm speakers wired in series add up to 8 ohms total. Connected in parallel, the outcome is more complex: for two speakers, you multiply together each individual impedance, then divide the result by the sum of the impedances. For example, two 8-ohm speakers in parallel are (8 * 8 ) / (8 + 8 )or 4 ohms total.

Impedance Matching

An amplifier's outputs have an impedance rating just as a speaker does; 4-ohm speakers should be used with the 4-ohm speaker outputs of an amplifier, and 8-ohm speakers should be used with 8-ohm amplifier outputs. A mismatch of speaker and amplifier impedances can damage the amplifier's circuits; it also results in distortion and poor sound quality. This issue is most important when you listen to loud music, as the demands on the amplifier for power are greatest at high loudness levels.

Speaker Impedance

Originally, most speakers were 16 ohms because this worked best with tube amplifiers. Later, speaker drivers with about 8 ohms were the right match for transistor amplifiers because they provided the best balance of output power, volume, fidelity and low distortion. Early automotive stereos necessitated speaker drivers with the much lower 4 ohm impedance to get the needed volume, albeit with some loss of sound quality because the driving voltage was limited to 12-volt DC automotive battery-alternator electrical systems.

Modern automotive amplifiers are able to internally jack their output voltage as evidenced by those annoying thumpers prowling the streets. An amplifier has to apply twice the voltage to an 8 ohm speaker to get it to allow the same amperage (and thus watts) as a 4 ohm speaker. Inversely, an amplifier intended for 8 ohm loads might pass too much current if used at moderate to high levels with 4 ohm speakers, which would melt its output transistors. For that reason, it is imperative to completely understand the output constraints of the amplifier that will be used, as well as the rationale for changing speaker impedance in the first place--either up or down.
Series or Parallel Connected

The best and easiest way to obtain desired impedance for a system is to play with the number of drivers and their configuration. For example, if two 4 ohm speaker drivers are connected in series (amplifier plus to speaker 1 plus, speaker 1 common to speaker 2 plus, speaker 2 common to amplifier common), the system impedance will be 8 ohms. Connected in parallel (amplifier plus to both speakers 1 and 2 plus, and both speakers 1 and 2 common to amplifier common), the total impedance is 2 ohms. Four 4 ohm speakers with two parallel connected pairs connected in series will result in--yes, 4 ohms all over again. Two parallel connected 4 ohm speakers connected in series with one 4 ohm speaker will yield a 6 ohm system. Two series connected 4 ohm speakers connected in parallel with a 4 ohm speaker will yield 2.67 ohms. The formulas are easy: For series connected speakers, just add all the impedance values, period. For parallel connected speakers, break out the calculator, it will be: 1/R total equals 1/R (speaker 1) plus 1/R (speaker 2) plus 1/R speaker 3 ... and so on.
Protecting the Amplifier

While putting a 4 ohm speaker on an 8 ohm amp is risky business, an 8 ohm speaker with an amp designed for 4 ohms is OK, although the highest attainable volume may be lower.