Testing the OHM's of Speakers?

[mikespe]

I have 4 10" speakers with this name on them: Linear Dynamics DM-75R. However that is ALL the information there is other than each cabinet is rated 200 watts. These are still in the cabinet (2 cabinets) and were used for my stereo about 15 years ago. There is a midrange and tweeter in each cabinet as well. I thought about just changing the jack on the back of the cabinet (typical stereo jack that clamps the bare speaker wire) to a 1/4" jack to use them for my amp. However, there is no information regarding the OHM's of the speakers? Is there a way to test these speakers to see what their rating is? I tried searching Google and came up short for these speakers.

Thanks

[cantolina]

Originally Posted by mikespe

I have 4 10" speakers with this name on them: Linear Dynamics DM-75R. However that is ALL the information there is other than each cabinet is rated 200 watts. These are still in the cabinet (2 cabinets) and were used for my stereo about 15 years ago. There is a midrange and tweeter in each cabinet as well. I thought about just changing the jack on the back of the cabinet (typical stereo jack that clamps the bare speaker wire) to a 1/4" jack to use them for my amp. However, there is no information regarding the OHM's of the speakers? Is there a way to test these speakers to see what their rating is? I tried searching Google and came up short for these speakers.

Thanks

Use a multimeter across the terminals to get the static resistance measurement....

Test each speaker alone (no connections)

[mikespe]

Originally Posted by cantolina

Use a multimeter across the terminals to get the static resistance measurement....

Test each speaker alone (no connections)

Hey thanks! I totally forgot that I purchased a multimeter from Harbor freight Tools about a year ago but never used it! I checked the speaker and it read 5.0 on the meter. I am assuming that would be considered a 4ohm speaker or is my assumption wrong?

Thanks

[blue metalflake]

I'm pretty sure the actual working impedance is higher than the static, so they're probably 8 ohm.

[mikespe]

Originally Posted by blue metalflake

I'm pretty sure the actual working impedance is higher than the static, so they're probably 8 ohm.

So if I understand OHM's correctly then, if I put 2 speakers in a cabinet it would then be a 16 ohm cab correct? If this is true then my cab idea won't work with these speakers. I was looking to make a cab for my VCXD which is 4 ohm.

Thanks

[robt57]

Originally Posted by mikespe

So if I understand OHM's correctly then, if I put 2 speakers in a cabinet it would then be a 16 ohm cab correct?

Depends on how you wire them, this should help:

[mikespe]

Originally Posted by robt57

Depends on how you wire them, this should help:

THANKS! I never realized that many configurations could be made. One thing that always confused me...is there a difference in sound between the 3 different OHM configurations or is it merely an electronic thing?

Thanks Again!

[beach bob]

Originally Posted by mikespe

One thing that always confused me...is there a difference in sound between the 3 different OHM configurations or is it merely an electronic thing?

Yes indeed; it's pretty critical actually. The amp will be designed to run at a certain impedance, and the speaker impedance / wiring should match that rating. For instance, I have a Super Reverb w/ mis-matched speakers, currently wired for 8 ohms... but SR's are designed to run 4-10" (8ohm each), wired in parallel (similar to the left wiring in that pic), at 2 ohms. So right now the amp runs 'cool' and doesn't get the ideal tone. [but; that will be fixed soon ]

OTOH, I believe you could damage an amp by running a too low impedance load (speakers) with an amp designed for a higher impedance (say, a 2 ohm load into an amp that is designed for 8 ohms).

Re; your first post, I would be very careful about running stereo speakers as guitar amp speakers. They aren't designed to do that, and you could easily blow them. Unless we're talking bedroom volumes.

The Amp Central section of this forum has some people that hang there that know way more about this sort of thing than I do, perhaps you could post there?