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headunit rca voltage, volume level, setting gains


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Hello to all. First time poster here. I hope I am putting this in the correct place, I know this is a fully loaded question, mostly about matching head unit rca output voltage to my amplifier. I have done plenty of google searches, and searched on here also.

I just completed my first install in about 8 years. I did a fairly simple budget build in my 2008 Nissan Altima. I used a Pioneer 3800bhs head unit, passive 2 way components in the front doors for my front stage, and a single 12" 700 watt RMS subwoofer in a sealed box.  Both amps are in the trunk along with the subwoofer.

I goal is to have a 250 watt front stage, and a 700 watt subwoofer. I have a class FD Pioneer amp for the front stage, and a Pioneer class D monoblock for the single 12" sub.

To set the gains, I am using a True RMS DMM, and for the subwoofer gain set I am using a 50 hz test tone, for the front stage gain set, I am using a 1khz test tone at digital zero. According to ohm's law, my voltage on my 2 channel amp for my front stage should be 22.3 AC volts per channel, and my subwoofer AC voltage 37.4 volts.

My question here lies. I tested my RCA cables output voltage. The max volume is 40 on my headunit. At volume level 38 my Front RCA voltage is 2.63, 39 it is 3.31, full max volume 40 it is 4.01 volts.

My subwoofer RCA voltage is as follows, Volume 38 with subwoofer level 0 = 0.59, vol 38 sub level 10 = 1.86.  Volume level 40 sub level 0 = 0.93, vol 40 sub level 10 = 2.95.

Now with that said, the headunit has stated in the manual that it has 3 sets of 4v preouts.  Here lies my confusion. Why am I not able to achieve a full 4 volts with my volume level at max volume of 40 with the subwoofer level set to 10 (max) ??

According to my hours of research, I should be setting the gains on my amp with the volume somewhere around 75% volume which would be volume level 30 in my case. But, if it is better to set the gains with the volume level as high as possible while sending the strongest signal to the amplifiers to keep them from having to work so hard, is this really true?

So my questions are as follows,

Is there something wrong with the subwoofer RCA signal voltage since I was unable to measure 4 volts while at max volume with subwoofer level at 10?

Instead of using a True RMS DMM, should I use my ears to listen for distortion while setting my amplifier gains?  This just seems a bit intimidating. I don't have access to an O-scope.

What volume level is generally accepted if other than using the 3/4 max volume rule and using a True RMS DMM?

I do not have any speakers hooked directly to the Pioneer headunit, so how do I know if the headunit itself will distort?

Sorry for the fully loaded question and I hope I put it in the right place.

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The SMD tools would help find distortion easily. The  DD-1 or DD-1Plus. 

I think thats how all headunits are, the output voltage goes up as u turn up the volume. If that didnt happen, then we could theoretically set our gains with volume at zero or 1%, if full voltage could be achieved at any level. Also Pioneers are known for being distortion free all the way to 40. Maybe thats why they claim 4v, because they know u can max out volume(reach 4v)  without distorting.

im a noob so take my words lightly lol. And i dont know any of the math technigues of setting things, i just bought the tools so it would be easier lol theres enough shit to stress over with car audio, i didnt want to stress over the math techniques.

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  • 8 months later...

I know this is a pretty old post but I just wanted to post what I found when testing my RCA voltage outputs on my Pioneer AVH-X3800 which they claim the max voltage to be (4V)

I found the max volume on my headunit whilst playing a 60hz test tone at 0db to be at 36/40 w/sub output level @ 0 before I hear terrible distortion.

I took a multi-meter and measured the voltage output to be around 2V exactly

I then bumped the sub output level to +10(max) which Pioneer claim is distortion free:

Quote

Hi the speaker level settings allow you to adjust the db output of each speaker, Increasing to 10 will raise the Sub +10db higher than the other speakers. This output is clean, but depending on your set up and the amps this could cause distortion of the sub when at higher volumes

and I got a voltage output of around 4.5V ....now they claim the max output is 4V so this makes me think am I getting distortion/clipping signal now?

Naturally I backed it down to +6 which got me a nice 4V just to be safe.

 

Any thoughts?

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without using proper test equipment that measures distortion (DD-1 or oscilloscope), that +6 level giving you 4v could probably still be distorting. it may not be audible.

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3 hours ago, MünürYılmaz said:

I know this is a pretty old post but I just wanted to post what I found when testing my RCA voltage outputs on my Pioneer AVH-X3800 which they claim the max voltage to be (4V)

I found the max volume on my headunit whilst playing a 60hz test tone at 0db to be at 36/40 w/sub output level @ 0 before I hear terrible distortion.

I took a multi-meter and measured the voltage output to be around 2V exactly

I then bumped the sub output level to +10(max) which Pioneer claim is distortion free:

and I got a voltage output of around 4.5V ....now they claim the max output is 4V so this makes me think am I getting distortion/clipping signal now?

Naturally I backed it down to +6 which got me a nice 4V just to be safe.

 

Any thoughts?

Ya,.. what if at 4 volts your sending is a monster square wave ? Do you know 4v is clean?

 

And to that, flip side,  what if your leaving a ton of power on the table also?

I know in my testing, 2 clicks down was over a db and change loss. Just sayin. 

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36 minutes ago, Kyblack76 said:

Ya,.. what if at 4 volts your sending is a monster square wave ? Do you know 4v is clean?

 

And to that, flip side,  what if your leaving a ton of power on the table also?

I know in my testing, 2 clicks down was over a db and change loss. Just sayin. 

I totally agree with you

I'm sure those 2 clicks down was audible right? Distinctive change of tone. I'm either going to tune it by ear like most people or eventually invest in a DD-1...they're just a little pricey for a 1 time thing ...

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7 hours ago, MünürYılmaz said:

I totally agree with you

I'm sure those 2 clicks down was audible right? Distinctive change of tone. I'm either going to tune it by ear like most people or eventually invest in a DD-1...they're just a little pricey for a 1 time thing ...

I feel ya. But, dude, one time thing? Ive used my dd1 that ive had for 4 years, a A SHIT load,.. yes, i do rebuild alot, have had several builds, but dude, You will use it more than once. If you dont, borrow one. Like right now? Mine is 4 states away. I sent it to help a fellow basshead/friend. Its been to cali, washington, texas, Idaho, florida ,.. twice, upstate, Ohio, and other places..  And like i said, i used it on my one shit, way more than once. But, i do like your understanding/thinking in the matter. ;)

After using the dd1 for a few years, i bought, and have the dd1 plus. I like it even more ...... 

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Also bro,.... Im OG. I used a scope for years. From the 440 that every bass head on the planet has, to a fluke that i used for a good while.

 

IMG_0376.jpg

 

When i tested, the dd1 was acutally better at seeing noise. Talk about "cheaper" to. And, about 4 million times easier, and faster. 

 

If you want, when i get mine back, ill send it to you. Just cant promise when that will be lol. 

 

 

EDIT- and to answer your question about the 2 clicks being "audible".  No ,.. at 162 sealed on the dash, or pulling 57s at 20hz for 30 seconds,... No,.. its all just loud.

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On 12/02/2018 at 3:25 AM, Kyblack76 said:

Also bro,.... Im OG. I used a scope for years. From the 440 that every bass head on the planet has, to a fluke that i used for a good while.

 

IMG_0376.jpg

 

When i tested, the dd1 was acutally better at seeing noise. Talk about "cheaper" to. And, about 4 million times easier, and faster. 

 

If you want, when i get mine back, ill send it to you. Just cant promise when that will be lol. 

 

 

EDIT- and to answer your question about the 2 clicks being "audible".  No ,.. at 162 sealed on the dash, or pulling 57s at 20hz for 30 seconds,... No,.. its all just loud.

Wow I really appreciate the offer but I live in the UK so these little kits are a lot harder to get hold of lol I was thinking of paying someone local that had it just so I can tune my setup properly for once instead of doing it by ear :/ but I think I'm gonna have to purchase it one day just don't know when yet :p

 

And also waiting for Skar to update their amazon product list in the UK and stock up on some Skar EVL-12s or something. The UK market really lacks in nice subwoofers :( LUCKY AMERICANS <3

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17 hours ago, MünürYılmaz said:

Wow I really appreciate the offer but I live in the UK so these little kits are a lot harder to get hold of lol I was thinking of paying someone local that had it just so I can tune my setup properly for once instead of doing it by ear :/ but I think I'm gonna have to purchase it one day just don't know when yet :p

 

And also waiting for Skar to update their amazon product list in the UK and stock up on some Skar EVL-12s or something. The UK market really lacks in nice subwoofers :( LUCKY AMERICANS <3

Hey Im curious, do you guys get decent distribution of Pride and Alphard in the UK?

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