How to Set Your Gains Using Ohms Law and a Basic Multimeter 

Yes your right seen millions of videos and this was straight to the point and looks possible to anybody can do it

I running 2 1500rms subs at half ohm..so id.go.1500x.5=750×2subs=1500 and the square rt of 1500=38...so.38volts is my number..

@@ronnydisalvo80 no sir you have to use the rated rms output number of your amp....so say your amp is rated at 2000 rms at .5 ohm....multiply 2000 by .5 and find the square root with is approx 31.62.....

@@ronnydisalvo80 you have 2 subs wired in a way that gives you .5 ohm load

@@ronnydisalvo80 so how can I do that on mine bro ..??

I have 2 dual voice coil 4 ohm subs running parallel at 1 ohm and they are 1000 watts rms per sub. My amp is 3700 watts rms @ 1 ohm. Will that be to much for the subs to handle? When I do the math do I add the rms wattage of both subs together? After setting everything to 0 then raise the gain till I get my target voltage when I then turn up the bass boost and LPF the voltage goes up. Is that ok?

+Rizz1117 your amp is a bit too much for those speakers.

+Rizz1117 Between the RMS power of your subs and your amp, you'll go with the lowest one if they are not equal. So you would go with 2000 RMS for the 2 subs so you over power and blow them. You would want to target your AC voltage at 44.72 volts

I have a Orion hcca 12" dvc 2 ohm. I have it wired down to 1 ohm. When I do this formula do I use the final impedance 1 ohm or the 2 ohm to plug into this equation?

+You're Hating You got it. So you would connect your multimeter (on the voltage setting) to the speaker outputs of your amplifier and while playing a 50Hz (or appropriate frequency) tone, adjust the gain setting until you get to around 34.64 volts of output.

thank you for you video it was helpful.. I added some of the bass boss halve ways and turn down the lpf just a tad under the gain and the subsonic just a lil bit up like 1/16 of an inch and finally no more distortion thank for the help

Whether you use one speaker or 4 speakers, it’s all the same. Only difference is, when it’s more than one speaker, they will share the same power unless each speaker is rated at a different ohm(resistance).

You would use whatever impedance your subwoofer is wired to so if you have wired your DVC 4ohm sub down to 2ohms, R would = 2

***** Gotcha, thanks!

Yes

I have two dual 4 ohm 10 inch AB XRs I have them wired down to 1 ohm for my skar rp2k1d amp so you use what your amp is rated to not the subs

Bryant, thanks for your message. If your subs are single voice coil, 4-ohm subwoofers, you can wire them down to a 2ohm final impedance at the amplifier. This would send all 500 watts from your amplifier to your subwoofers which have a combined RMS power handling of 600 watts. If you would like a diagram on how to wire your subwoofers to a 2ohm load, go here - www.mtx.com/t/library-wiring-diagrams If your subs are dual 4ohm voice coil, you cannot wire them to a final impedance of 2ohms.

They are dvc subs what would be the best way to wire it

Bryant Washington The best way to wire your subs depends on the ratings of the amplifier you are going to connect them to. For example, with your current Kenwood amp, there really is no good way. You would either have to wire them to an impedance the amp is not stable at in order to get enough power to the subs or you would have to wire to a higher impedance that wouldn't give your subs enough power. With two 4ohm, dual voice coil subs, you can wire to 1ohm or 4ohms at the amp. With two 4ohm, single voice coil subs, you can wire to 2ohms or 8ohms at the amp. With two 2ohm, dual voice coil subs, you can wire to 2ohms or 0.5ohms (not recommended) at the amp. With two 2ohm, single voice coil subs, you can wire to 1ohm or 4ohms at the amp. Then you would need to find an amplifier that has an RMS power rating of as close to the combined power handling of your subwoofers (2 subs with a 500 watt RMS power handing would be 1,000 watts total) at whatever impedance you plan to wire them at. www.mtx.com/t/library-wiring-diagrams

what if you parallel one sub ,series the other sub ...and then parallel both subs ...??? Would that be 3 ohms ??

What kind of amp are you working with? What is the model # if you have it?

I forgot to mention that I also use Audio Control LC2I converter.

You would use the RMS power rating of your amplifier which would be 900 watts.

***** Huh? Then you would be tuning to give 900 watts RMS to a speaker that's only rated for 350 RMS at 2 ohm. My understanding is you should only be tuning to what the sub can handle...which would mean the opposite of what you recommended. So if the sub is rated for 350 RMS @ 2 ohm the target would/should be 26.46 volts, right? That or I'm completely misunderstanding how this works, which is possible....

snowmobileracer69 Sorry... I may have misunderstood the original situation. IF the amp is rated at 900 watts RMS at 2ohms and Artem Alforov has 1 subwoofer rated for 350 watts RMS and that is wired for 2ohms, he would use 350 for P in the equation. However, I would recommend trying to find a different rating and impedance that would more closely align with the subwoofers RMS rating. For example, MAYBE the amplifier is rated at 450 watts at 4ohms. IF the subwoofer is capable of being wired to a 4ohm impedance, this would be a better match. Without knowing the exact specs of the products, it's hard to say what the best possible setup would be. Sorry for the confusion.

26.45 is your target volts 350 watts rms x 2 for 2 Ω =700 square root 26.45

DC voltage is what the battery of the vehicle has but the output power from the amplifier is AC. Yes. We are using the gain to level adjust the input signal (varies depending on the head unit) so that the amplifier can send the best possible audio signal to the speakers. Be sure to use an appropriate frequency for your test disc depending on what type of speakers you have connected to the amplifier you are tuning. This video references 50Hz because the amp is connected to subwoofers. For component speakers, you would use a high frequency test disc. Refer to your speaker's specs.

***** I finally got around to playing with this and I tried setting up the gain but wasn't getting anything without any volume and with the radio on the numbers just jump up and down. So I need to make a tone mp3 or wav file in audacity. The crossover is fixed at 3800 Hz, 6/12 dB/octave and the other number for the woofer is 55-3200 Hz. I have MBQuart DSh 213 components. In something like this, what tone would I need to use? I'm just trying to walk through the whole process to understand how to tune something like this correctly. Do I just need to make a 3200 Hz tone and use that to tune the set? I guess since there's a tweeter, that's confusing me a bit since both are considered channel one for one door and channel 2 for the other. I unplugged them just like you did. Cool stuff by the way, but it's not quite the same watching and actually doing it since I have never done this, but I'm learning.

You can download test tones from MTX.com at www.mtx.com/t/testtones. For an amplifier that you are using to power full range speakers, you can use a 1kHz test tone.

***** Thanks!. I ended up making a few tones and tried using the 3200 tone and noticed that the gain at the lowest was 16 something volts! So I changed to the 1Khz and I got the number exactly matched to the speakers. To make the tones I only changed the Hz in audacity and nothing else. I also just saved as a windows file and that seemed to work. Channel one and channel 2 have the same gain dial so I only used that. Looking at your link, you have a left and right channel tone. When do you use those? I only ask since my gain says ch1/2 on it. So I just used the left channel to change the voltage on it. I figured it would be for both sides since the ch3/4 have their own dial, and so does the sub. Man, this is pretty neat once you get it working. Now I have an LP filter dial that goes from 50 to 200 Hz, I guess this is for the subs which I don't have any. Except for ch1/2, all my other dials are pretty much turned all the way down since I don't have anything else plugged in.

Depends if you're going to wire them in parallel or in series. In series your total ohms would be 8. In parallel your total ohms would be 2.

I’m an intermediate installer learning how to install my first setup and from everything I have watched and learned setting the gain at the exact level with a multimeter is the best way because the amp will not go above that voltage limit and potentially damage the sub with too much power, and I have also read that on your head unit the LPF, if you have one should be off and any bass levels should be flat. Bass boost is not a volume control and I would leave it at 0 on the HU and amp as the gain is already transmitting the maximum performance range that the sub can get to so you’re not missing out on that much power. So to sum it up, the gain, at the correct level, will provide for the best and maximum performance out of your sub without going past the voltage that would potentially blow or damage your sub. Set your LPF and Subsonic filtering as necessary, the standards are LPF at about 80 and subsonic at about 35 but that depends on if you have a ported or sealed box which there are videos that better explain that.

@@bryan3327 this is what I was looking for and answered my question thoroughly! Thank you so much!

@@handon11 No worries! I had the same concern as well being a noobie and trying to install a sub on my own and after one blown voice coil it has definitely been a learning experience so I’m glad I could help!

We use a 50Hz tone because that is a common frequency range for most music. For your speakers, you would use a frequency that is somewhere in the frequency response range of their specs. For example, you wouldn't use 50Hz if the speakers have a frequency response of 75Hz to 20kHz. You would want to disconnect your subwoofers to set the gain on the amp that powers your speakers. Once that is done, disconnect your speakers from their amp, reconnect your subwoofers to their amp, and set the gain on that amp using an appropriate tone. Hope this helps.

Keep in mind we are setting up a subwoofer amp and subwoofers play lower frequencies than speakers so a 50 Hz tone is good for subwoofers but would not be good for speakers. For speakers you would want something more like a 1kHz tone.

@@MTXAudioUSA Thanks for the informative video and answering all these questions that I've had myself. Much appreciated!

If you want balanced system, that 0dB is just fine. Not everyone wants SPL build

If you want your amp to output 1000w and your ohm load is 1, then yes you are correct.

37.41 is your target since your amp is rated higher than your subs you use 350 watts rms x 2 for 2 subs 700 atts rms total x 2 for 2Ω load = 1400 square root =37.41

The audio I do on bikes, obviously wanna higher RMS on your amp than your speaker... I set gains by going by the Voltage x Amp = Wattage. and from there i can adjust to each speaker giving it the exact amount RMS with the radio all the way up so they cannot blow the speakers. LOL

+frank lucas Are you playing music while testing your speaker terminals? If you are, check to see if your gain is turned all the way down. If that doesn't fix your problem, you either have a signal issue or a bad amp. The amplifier is getting power but may not be getting signal from your head unit which could be a problem with the head unit, the RCA cables, or the amplifier. But if you can test to ensure you are getting signal to the amplifier, that would rule out one more potential issue.

The 12 volts you're getting at the amp is DC. When you test for volts on the speaker output switch your multimeter to read AC volts ...

You got it! Even though your amp is capable of more power, this way you won't overpower the subs and your amp should run nice and cool.

Yes. If you match the gain to your source it will never clip up to the max volume on the radio. Some radios clip internally at higher volume so you have to figure out at what setting the head unit clips and never turn it up past that. Clipping is basically like shorting out your voice coil out with DC at the top and bottom of the sound waves. Literally HORRIBLE for your speakers.

The amount of subwoofers you have doesn't matter.. It's how you wire them and what impedance the amp sees at the end. So if you have two dual two ohm wired to 0.5 ohm then you use 0.5 ohm. If you wire it at 2 ohm then use 2

@New Alert That's correct. I'll edit my post

Remember... by setting your gains properly, you are setting the amplifier output that you need for the RMS power handling of your subwoofers. If you feel the output isn't what it should be, consider looking into your enclosure volume and tuning. If you do the math calculation of V = square root of Power x Resistance and it is around 60 volts, I would stick to JL's recommendation. On their website, this amplifier has an RMS rating of 1200 watts at 3ohms. So, the calculation would be V = square root of 3600 which = 60.

For Power (P) in the equation, use whatever amount of power you want the amplifier to put out at the impedance your subwoofers are wired to. For subwoofers and when setting the channels used to power your subwoofers, you would use a 50Hz tone. For setting gains on amplifiers or channels of amplifiers that are used to power full range speakers, you would use a tone more like 1kHz. Both tones can be downloaded from our website at www.mtx.com/t/testtones

+William Gingrich You would probably want to use the 60 watts RMS that the speakers are rated for. By using 65 watts, you are setting up your amplifier to put 65 watts to your speakers which are only rated for 60 watts. Other than that, your calculation looks good. If your amp has gains for both channels, you would do this for each channel.

Anthony Conger First, disregard any power ratings other than RMS. 2 - subwoofers with a rating of 400 watts RMS each = 800 watts for your desired amp output so P = 800. For "R" the value would be whatever impedance you have wired your subwoofers to. So the equation would be V = the square root of 800 x R.

+Michael Gardiner If you have wired your subwoofers down to a 2ohm load at the amplifier, what is your amplifier's RMS rating at 2ohms? You would take that number multiplied by 2 (ohms) and then find the square root of that answer to get your V = voltage to set your gain to.

But your amp RMS is always the same? so basically what you are saying is that whether i have a 200rms or 700rms sub, the voltage for the gain is always the same? surely the subwoofer RMS plays a role in this calculation? or have i got it wrong

+Michael Gardiner If you wanted 200RMS at 2 ohms you would want 20 AC volts at the speaker terminals of the amp. If you wanted 700RMS at 2 ohms the voltage would be 37.42 The formula they have used here, is to attain the maximum RMS output of their amplifier. If you do not need to maximum RMS output of the amp because your speakers can't handle it, you would add together the total RMS wattage of whatever subwoofers you have and plot your voltage based on that wattage at 2 ohms (or whatever final load your subs are wired to) Example: Your amp does 1500 watts RMS, but your subs only handle 250 RMS each...(500 RMS total). Take 500RMS X 2 ohms = 1,000 (square root that) = 31.62 AC Volts.

abdullghoriO1 once the gain is set properly, you can use your EQ adjustments to fine tune the sound for your listening preference.

I tried this on my new system. Everything's new except for the RCA's. I can't get a reading in my multimeter. Could it be the RCA's

@@tpm1868did you use the DC voltage setting to check your power wire(12v+/-)? when you turn the head unit does the remote receive a dc current(12v)? (you can use the ground for the negative on the multimeter for these two tests/probes) -------------------- You can test the RCAs with a multimeter if you set it in AC volts and probe the center pin and outside ring of the same plug/wire, while music is playing if you get an ac voltage that is going up and down they are working as intended. If you can answer some of my questions, I can defiantly help you figure out what the issue is and we can get you jamin just like that reggae playlist you have on your channel. Been letting it play all day...

@@Dheath thanks for getting back to me. Had to replace my deck. Dead sub out rca. Now with new deck everything's working just fine

No. You always want to start with a flat signal.

The only time you should really ever touch a bass boost feature is when the bass of the track is recorded lower than others. Many people think a bass boost feature give you more performance but it simply doesnt. All it does is increase the volume of a dedicated range of lower frequencies. Which if set too high will cause distortion and clipping. Which is not good for amps or subs.

settings on head unit should all be flat, any bass boost turned off. If you have a bass control knob that connects to the amp, that should be turned all the way UP. Bass boost to me is kinda pointless, agree with what Brucie said. If you feel like you need to turn bass boost on, buy higher wattage RMS speakers. I currently have 2 Rockford P3's, 1200W RMS total between them.

@@GlycerinZ no you didn't understand. It's not bass boost, it's subwoofer level control essentially an electronic bass knob. It's built into the headunit.

@@dtmfool789 I'd leave it at 0.. you have a bass control knob connected to the amp, right? use that. If you don't have one, i'd get one. It's best to have all the settings within the deck set to default and EQ off. Are you sure it's not the bass level associated with mid and treble? Because my car also has Treb/Mid/Bass, but those should all be set flat. But you are right, if you turn it up, it will go past the target voltage and most likely cause clipping.. which will fry your subs and then you won't be a happy Daniel.

We assume you have a Rockford Fosgate P2D2 which is a dual voice coil subwoofer in their P2 (Punch) lineup. Depending on which size you have, your RMS power handling is between 250 and 400 watts. Peak/Max power handling on the 15" model is 800 watts so without knowing what exactly you have, we cannot help with the equation. Please check your specifications of the exact model #'s you have and ONLY use the RMS ratings. Do not use peak or max power ratings.

***** thnx for the reply i checked and i have a rockford T2 15 inch

Sandeep Raj Moenilal OK, that subwoofer T2D215 has a 1200 watt RMS power handling. Would still need to know the exact specs of the amplifier.

1300

If it's flashing it's ok solid no good

Makes sense set the sound you want...then adjust the level of the sound you like to play the loudest safest gain level

@@ukokepaoa5536 filters should only lower the power or loudness. For most amps, The only adjustment I can think of that increases sound or power other than the gain knob; would be the bass boost switch or knob found on some amps

43.01 volts only if your RMS is 1850 watts at 1 ohm. Times you RMS amplifier wattage by the ohm load your going to run you amplifier at then square that shit.

You don't need the load (speakers) connected because you already calculated the total resistance when you measured the ohms of the speakers. Speakers are only to actually hear the sound. The signal is still present at the output terminals

+Krew808 Since the enclosure has a RMS rating of 400 watts, you would only want to use 400 watts RMS of your 500 watt RMS amplifier. So the calculation would be V = square root of 2ohms x 400 watts. V = square root of 800. V = 28.28 volts.

+phillip shevchenko for P (power) in the equation, you use whatever amount of RMS power you want to get out of the amplifier. In your case, since your subwoofer has an RMS rating of 400 watts, you would typically use 400 watts because you wouldn't want to send 500 watts to a subwoofer with a 400 watt rating. HOWEVER, your amplifier does 500 watts RMS x 1 @ 2ohms but your subwoofer isn't a 2ohm subwoofer. Your amplifier does 300 watts RMS x 1 @ 4ohm which is what your subwoofer is. So... the equation is V = square root of P x R. V = square root of 300 (amplifier's RMS rating at 4ohms) x R. For R (resistance or impedance), since your subwoofer is a single 4ohm voice coil, your only option for R is 4. V = square root of 300 x 4 V = square root of 1200 V = 34.64

Thankyou

If you go on Kicker wiring (YELLOW) diagram, I am using the top right diagram. On images 4ohm voice coil to 2ohm parallel.

Rms rating that you use depends on the ohm load of you sub

P = RMS power rating of your amplifier at whatever impedance (R=resistance) you have your subwoofers wired to. If you have 2, 3, 4, 5, or however many subwoofers you have, what impedance are they wired to at the amp? That is the number you would use for R (resistance). So in your case, P = 500 watts but only if your subs are wired to 2 ohms. If your subs were wired to 4ohms, you would use the 4ohm RMS rating for your amplifier for "P" in the equation. P = RMS rating of your amplifier at whatever impedance your subs (any number of subs that are connected to that mono block amplifier) are wired to. R = resistance (impedance) of your subwoofers at the amplifier in ohms. If you wire two single 4ohm voice coils in series, you would use 8ohms. If you wire two single 4ohm voice coils in parallel, you would use 2ohms. See our wiring diagram tool to learn how to wire subwoofers to different impedances - www.mtx.com/t/library-wiring-diagrams Assuming you have your two subs wired to 2ohms at the amp, your equation would be: V = square root of (500 * 2), V = square root of 1000, V = 31.623 volts

Since your subwoofers have an RMS power handling of 400 watts each (2 subs x 400 watts each = 800 watts total), your amplifier is a bit underpowered for what the subwoofers are rated for.

***** Awesome! Thanks! But I'm wondering, since the max rating of the Subs is 400 RMS, would it be a better idea to use 400? To be easier on the subs? Really appreciate the help! I'm looking into a possible change to me setup with going with your guys 12" dual voice to wire that down to 2 ohms. So it'll be the same settings. I think it'll save me some trunk space for a rear mounted single sub instead of having this big ol box. Though's on that? I'll most likly have to make a small box, cause I don't think it's a free air rated sub. Thanks again!

Hott Toddy If you have 2 subs at 400 watts each and your amp is rated at 500 watts x 1, you would only be putting 250 watts to each sub. The amp is a bit underpowered. If you have 1 sub, then yes, you would use 400 watts in your equation so that you don't overpower the subwoofers by sending too much power. If you were to buy a single 12" dual 4ohm voice coil sub and wire it down to 2ohms at the amp, you could go with our 5512-44 - (www.mtx.com/55-series-car-subwoofer) and use the same amp or our 7512-44 - (www.mtx.com/75-series-car-subwoofer) but with that sub, your amp would be a bit underpowered again.

***** Awesome. So equation is: AC Volts = Sqrt 500 * 2 AC Volts = 31.62

Lol

+Yankeesftw23 Are you bridging the two channels together? If so, Sony should also provide an RMS power output of the amplifier bridged if it is a bridgeable amplifier. Not all multi channel amplifiers can be bridged.

+MTX Audio USA No i am not bridging the two channels and I believe the amp rms is 185w

+Yankeesftw23 Your subwoofer has an RMS power handling rating of 350 watts. Your amplifier's unbridged RMS output is rated at 185 watts per channel at 4ohm or 200 watts per channel at 2ohm. Since your subwoofer is a SVC 4ohm sub, it can only be wired as 4ohms at the amp which means you would be providing 185 watts to your subwoofer that wants 350 watts to perform properly. You should consider getting an amplifier that is better matched to your subwoofer.

+MTX Audio USA Alright thank you for the info and do you reccomend amplifying the rear speakers in my car. Im keeping the receiver stock for now will it affect my sound quality tremedously?

Mary Joan Montalvo Most likely..get a better one!

Assuming your subwoofer is wired at 2ohms, your calculation would be V = square root of 600 x 2 which = square root of 1200 which is 34.64 volts. Make sure all of your filters and crossover/tuning settings in the head unit and the amplifier are set as explained in the video.

If the amp is bridgeable use that rms instead.. DMM leads go on the bridge out of A and B.. simplest way

It could... But manipulating the audio signal using features like bass boost and loud settings is a bit different than setting your gains. When you set your gains, you are level matching the output of your amplifier to the RMS power handling of your speakers/subwoofers to ensure a good combination and to not over or under power your speakers.... When you use bass boost and loud settings, you are actually manipulating/changing the audio signal prior to any amplification of it. This is why we recommend setting your gains with no bass boost or loud settings on. Once your gains are set appropriately, if you want to tweak and tune your system to your personal listening preferences, using these features can help. But if your bass boost is all the way up and your loudness setting is all the way up, you could distort your subwoofer whether your gains were set correctly or not because those features can cause a clipped signal to be sent to the input of your amplifier before the amp gain ever comes into the scenario. Hope this makes sense.

He has 500 watts running through both subs buddy, both subs wired together are rated 800 rms

+Carlos Portillo Not enough info here to calculate the equation. How many subs? When you say dual, does that mean there are two subs or they are dual voice coil subs? What is the subwoofers RMS power handling rating? What impedance are your subwoofers wired to? What is your amplifiers RMS power rating at whatever impedance you have your subwoofers wired to?

Sorry there are two 15" SVC subs with 600watt rms each wired to 2ohms.....the amp is a Power One Series Monoblock two channel Class A/B Car Amplifier RMS Power Rating: 4 ohms: 250 watts x 1 chan. 2 ohms: 500 watts x 1 chan. 1 ohm: 1000 watts x 1 chan.

+Carlos Portillo If the subs are SVC 4ohm voice coils, your two subs can be wired together for a final impedance of either 2 or 8ohms at the amplifier. Since you have a two channel amplifier but listed ratings for 1 channel, I assume you are bridging the amplifier. Assuming 2ohms at the amplifier, your amp will have an output of 500 watts. You want an output of around 1200 watts at 2ohms to get the whole performance of your subwoofers. Based on what you listed, the amplifier isn't powerful enough for your subs.

+MTX Audio USA Thanks any amp recommendations?

+MTX Audio USA just got a 1200watt rms kicker amp

Jeremy Wood Yes. Even if your amplifier is bridged and your speakers are wired in series, you still just input the #'s into the equation. Use whatever impedance your subs are wired to in series as the "R" in the equation. For the "P" in the equation, you would use whatever your subs RMS power handling rating is and multiply by two since you have two woofers.

40/50Hz is for subs only, 1KHz is for regular speakers. I prefer 40Hz tone

You should be able to select the proper type of voltage (AC) and make sure your leads are inserted into the proper socket. You should probably refer to your multimeter's manufacturer's page for an owner's manual.

It has 200 or 2000 for alternating voltage

So I'd assume 3.4 comes out to 34 its just moved the decimal to fit if voltage goes up to 200

You are correct. You should use the total RMS power or your subwoofer(s). In our example the total RMS power handling is the exact same (500 watts) as the RMS output of the amplifier. By using the total RMS power handling of your subwoofer(s), you can use an amp that has more RMS output than you need and be confident that you aren't going to overpower your subwoofer(s). If you would use the RMS output of the amp without considering the power handling of the subwoofers, you would be setting the gain to maximum output which could be bad for your subs depending on their rating. Thanks for bringing attention to this. We've answered this question multiple times in the comments. It's just that our specific example is exactly the same RMS rating for the two subs (250 watts each) and the amplifier (500 watts x 1).

If you are using an external, dedicated crossover for the audio signal that you send to all of your amplifiers, I would recommend setting your head unit to be flat with no equalization done through the head unit and just manage any tuning through the crossover only. Hope that answers your question. Sorry for the late response.

Np on the late response ! So if I understand u correctly I should eliminate my secondary eq and connect straight to the head and keep the signals flat then tune it with my crossover! Am I correct?

MTX Audio USA hi I’ve been trying to figure this out forever my sub is dual 2 ohms I have it wired down to 1. So would it be my rms times 1 (obviously 500) or do I still do the 2 as well? Also my sub is rated 500rms

Interesting study. When I BT my Apple to my head unit, the two units sync volume. Up to 50% head unit volume, the Apple vol runs @50%. As I increase past 50%, the Apple vol follows up to 100% with literally no distortion. I set my amp gain @ 85% on the head unit.

Use the channel power and test each channel output assuming all channels are wired to the same impedance.

30

1, so your target voltage would be 22.36 in this example however, do not turn your radio all the way up, low level outputs can still have distortion. 3/4 volume would be more advisable unless you have access to an Oscilloscope, a DD-1 or another similar device to check at what volume level the head unit distorts.

+Daniel J Make sure you are using your amplifiers RMS power output ratings. Not the MAX or peak rating.

+MTX Audio USA yea that's what I was going for, the amps output rating is 1000rms at 1 ohm. (It's a 1 ohm stable amp) so that gives me 36.1 Vots yet like I said even I turned the gained all the way my DMM reading wouldn't be anywhere near that for some reason. I just did the ear test to sure there's no clipping, maybe I need to take it to a pro.

+Daniel J Could be something to do with the output signal of the LOC... Could be something to do with the wiring/impedance of your subs being incorrect... Could be a crossover or filter setting that is limiting the output... Take it to a reputable shop and ask them to check it over for you. They may charge you a shop/labor fee but it will be worth it in the long run to make sure your system is setup properly. Spend a little now to save yourself from replacing blown equipment.

Marcus43 34.64

Marcus43 yep! he's right! 34.64

Marcus43 If your AMP is more powerful then your speakers you can use the RMS of the speakers with the same “ohms law” equation to achieve the same none clipping multimeter voltage desired

Dual Voice coil or Single Voice coil doesn't matter. Just choose the impedance the amplifier will be working with and do the calculation. In your case, V = square root of 400 watts * 2ohms... V = square root of 800... V = 28.2843

+yousuf kan a TN12-04 subwoofer is a single voice coil, 4ohm, 200 watts RMS subwoofer. If you have two of them, your final impedance at the amplifier would be either 8 ohms (if you wired your subwoofers together in series) or 2 ohms (if you wired your subwoofers in parallel). Depending on which impedance your subwoofers are wired to, this would be your value for "R." Since you only want to put 400 watts to the pair of subwoofers or 200 watts to each subwoofer, 200 or 400 would be the value you use for "P". Your amplifier output is what we are trying to level match when setting gains so the amplifier ratings are not used in the equation. Just the impedance (R) and RMS power handling (P) of your subwoofers are what is used to determine how much voltage you want coming out of your amplifier. Your amplifier is rated for more power than the subwoofers so be careful not to overpower them.