multimeter 2ohm question

[towncarblue 10+ year member]

i have a 2 channel amp and i adjusted the gain on the amp using a digital multimeter , for my 2 front door speakers [ midrange and up ]

i had it adjusted for 100w rms per channel @ 4ohm which is what it goes for.

i decided to add the rear speakers to it and now i need help.

do i adjust it at 100w rms @ 2 ohm [14.14 v ] or at 200w rms @ 2ohm [ 20.0 v ]?

what is the correct one ?

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[Jepalan]

You have to tell us the exact brand and model numbers of all equipment in order for us to help you. The answer depends on the type of amp and speakers

 

[towncarblue 10+ year member]

amp is a MB Quart DSC 2150 http://www.sonicelectronix.com/item_13494_MB-Quart-DSC-2150-DSC2150.html

speakers are Image Dynamic CTX-6.5cs fronts http://www.sonicelectronix.com/cat_m178_i29_image-dynamics-6-5-component-speakers.html

and Polk Audio db6501 for the rears http://www.crutchfield.com/p_107DB6501/Polk-Audio-db6501.html?tp=106

 

[negolien]

Are only subs adjusted to rms x ohms then find the square root?

 

[BoomTaco64]

100w @ 2ohm will be 14.14 volts AC

 

[towncarblue 10+ year member]

will the amp push 100w per speaker or 50w per speaker if its adjusted at 14.4 v AC

 

[negolien]

Wait Wait you have a 2 channel amp now your adding another pair of speakers to it? I' am confused.

 

[BoomTaco64]

100w @ 2ohm per speaker. actual voltage at the speaker will vary as the wire and the length of wire and connectors will add a little resistance and lower the voltage output.

 

[Jepalan]

He is wiring his 4 ohm front set and 4 ohm rear set in parallel on a 2-channel amp. That amp can push 300 WRMS x 2 into 2 ohms no problem. The speakers can all handle 100 W RMS each (4ohms).

In parallel, each speaker sees the same voltage, so you calculate voltage either using 100W into 4ohms, or using 200W into 2ohms. In either case, the correct answer is to set your gains to 20volts.

 

[bbeljefe]

If your gain is set properly at 4Ω there is no need to change it when you wire down to 2Ω... and it doesn't matter what brand of equipment or if it's subs or mids.

Gain is a sensitivity matching device that takes place in the preamp stage and it does not matter what's connected to the outputs. The only exception to that would be if you were setting an amplifier so that it doesn't output its maximum power.

 

[towncarblue 10+ year member]

thank you so much for not solving my problem //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

i see now i just need to make sure its at 20V