Would like advice on this set up

[Water Bear]

Hello to the forum!

I would like to share my planned system and hear some feedback.

Currently I'm running 50x4 @ 4 ohm into Polk db 6.5 door speakers and 300x1 @ 4 ohm into a Polk MM 10 sub (~.65 cft sealed enclosure). Amps are Alpine's previous generation MRX series.

Problem: The sub is too weak. I have to put it around +6db gain on the EQ for it just to match the mids, which are almost certainly underpowered (front components are rated 100 RMS).

The sub amp is rated 500x1 @ 2 ohm. I am seriously contemplating upgrading to a Sundown SA 12 with dual 4 ohm coils so I can wire it down to 2 ohm and get 500 out of my amp. Looking at a ported box around 1.6 cubes, noting the recommended enclosure size is 1.5-2 cubic feet but I've read that closer to 2 cubes @ 35 hz tuned freq is best.

Questions:

1) Is the sub going to be underpowered? It's rated @ 750 RMS and all signs indicate it can take much more. I'm not too far off the ~560 watt "minimum" most places recommend, aka 75% of rated RMS.

2) Is that particular sub going to be too much? I'm not trying to rattle the doors off. A friend of mine has a Sundown X series 15 on like 1500+ watts and that **** was down right painful when cranked. I just want to bump good, but not at all trying to wake up the neighborhood.

Any advice appreciated.

Edit: Forgot to mention, before anyone comments: I believe the gains are set correctly. I set gain using a multimeter. Output voltage = square root of watts times resistance.

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[BOOMINGRANDPA 5,000+ posts]

idid see what hu and pre amp volts u have if gain is low with factory hu or 2v preouts i don't care what meter says set gain higher, go by jeffs rule bass hard with hu set at 90% 5 mins if amp ain't hot u can raise gain a tad.. yeah sa would sound good in 2cf (which after sub disp would be 1.85 keep that in mind don't go to small) also make sure port is right better if u post link i'll tell u i box is anywhere near close to right.. as far as power goes if u gonna run 560rms u should get more efficent sub i'd say fi alpha would be good maybe even sundown E require less power to get loud most peeps run 1k or so to sa.. Alpha Series - Alpha 12 | Fi Car Audio

 

[Water Bear]

idid see what hu and pre amp volts u have if gain is low with factory hu or 2v preouts i don't care what meter says set gain higher, go by jeffs rule bass hard with hu set at 90% 5 mins if amp ain't hot u can raise gain a tad.. yeah sa would sound good in 2cf (which after sub disp would be 1.85 keep that in mind don't go to small) also make sure port is right better if u post link i'll tell u i box is anywhere near close to right.. as far as power goes if u gonna run 560rms u should get more efficent sub i'd say fi alpha would be good maybe even sundown E require less power to get loud most peeps run 1k or so to sa.. Alpha Series - Alpha 12 | Fi Car Audio

Head unit is a Pioneer w/ 4 volt pre amp outs. Connected to amps using RCAs on all 6 channels. I set the gain with the volume at 30/40 using a pure 60 hz test tone (of course the speakers were all unhooked).

With amplifier gain set to minimum, I was actually getting exactly 4 volts out of the 4 channel amp.

Thanks for offering to help! This is the biggest ported 12" box I could find on woofersetc:

SQP112 - Ground Shaker 12" Single Ported Box

It's 1.75 cubes...maybe not big enough.

 

[BOOMINGRANDPA 5,000+ posts]

i don't even have to look at it to know it's tuned to high.. theres a guy on ebay makes good boxes some of his prefabs are tuned high too but u can email him and he'll make 1 how ever u like and u can get it with out carpet or terminals to save $ if u want.. this is basic version he has stge 2 and 3 as well with bracing and rounded corners this is made to sa specs little bigger would be better with your power but we can talk u into a bigger amp later lol.. that box would work good with E too and port seems small but if u can stand a 16" high box it's actually over 14sq in port per cube which is perfect, but like i said u can get that box with bracing or rounded port lik 1" shorter 3"wider or what ever just email him.. STAGE 1 - PORTED SUBWOOFER MDF ENCLOSURE FOR SUNDOWN SA12 SUB BOX | eBay

 

[Water Bear]

i don't even have to look at it to know it's tuned to high.. theres a guy on ebay makes good boxes some of his prefabs are tuned high too but u can email him and he'll make 1 how ever u like and u can get it with out carpet or terminals to save $ if u want.. this is basic version he has stge 2 and 3 as well with bracing and rounded corners this is made to sa specs little bigger would be better with your power but we can talk u into a bigger amp later lol.. that box would work good with E too and port seems small but if u can stand a 16" high box it's actually over 14sq in port per cube which is perfect, but like i said u can get that box with bracing or rounded port lik 1" shorter 3"wider or what ever just email him.. STAGE 1 - PORTED SUBWOOFER MDF ENCLOSURE FOR SUNDOWN SA12 SUB BOX | eBay

That's awesome, thank you! That looks like a perfect way to get the box I need.

If the same enclosure works with a Sundown E I just might do that. I will probably be upgrading the system in the future and wanted to get something that could go up. But if the E on 500 watts is loud enough I wouldn't mess with it.

 

[BOOMINGRANDPA 5,000+ posts]

That's awesome, thank you! That looks like a perfect way to get the box I need.
If the same enclosure works with a Sundown E I just might do that. I will probably be upgrading the system in the future and wanted to get something that could go up. But if the E on 500 watts is loud enough I wouldn't mess with it.

it'll be so much louder ported than the polk u probably wont need upgrade however i recommend the sa and bigger amp or FU750 (see in my avatar made in us $189 12") and bigger amp.. if u want to get him to do custom box as in shorter and wider pm me and i'll tell u how big port and long needs to be cause if u change it that port won't be big enough.. most prefabs have like 7-11 sq in port per cube and sub has issues but also they tuned at like 43hz but some of his say 31-35 hz just remember that don't count sub disp so if u want 35hz get1 says 33 hz see what i mean?,, he and i have been trading emails and he'll model 1 up for u the shape and port u want., he's done 4 for me with my specs and ain't mad about it lol..

 

[Water Bear]

it'll be so much louder ported than the polk u probably wont need upgrade however i recommend the sa and bigger amp or FU750 (see in my avatar made in us $189 12") and bigger amp.. if u want to get him to do custom box as in shorter and wider pm me and i'll tell u how big port and long needs to be cause if u change it that port won't be big enough.. most prefabs have like 7-11 sq in port per cube and sub has issues but also they tuned at like 43hz but some of his say 31-35 hz just remember that don't count sub disp so if u want 35hz get1 says 33 hz see what i mean?,, he and i have been trading emails and he'll model 1 up for u the shape and port u., want he's done 4 for me with my specs and ain't mad about it lol..

If I end up with too much, I can always EQ it back. Sounds like a good problem to have //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

I'll probably stick with sundown. After hearing my friend demo his and reading up on them I really like the brand and want to give it a try.

 

[Jeffdachef 5,000+ posts]

Head unit is a Pioneer w/ 4 volt pre amp outs. Connected to amps using RCAs on all 6 channels. I set the gain with the volume at 30/40 using a pure 60 hz test tone (of course the speakers were all unhooked).
With amplifier gain set to minimum, I was actually getting exactly 4 volts out of the 4 channel amp.

Thanks for offering to help! This is the biggest ported 12" box I could find on woofersetc:

SQP112 - Ground Shaker 12" Single Ported Box

It's 1.75 cubes...maybe not big enough.

HORRIBLE BOX fking garbage, never look at sh*t like that again, BURN IT NOW. That is actually closer to 1 cube after displacement. Not 1.75 usable. Its Gross cubic feet meaning before you subtract the space the port and sub takes up. That port is waaay too small as well, might as well have a leaky sealed box. Complete and utter box design fail.

Also if you were using a 0 db test tone with the multi-meter method, you did it wrong and are completely undergained because most music is recorded with -10 db levels of bass so you basically fked yourself out of all that possible output. Thats why the DMM method is completely and severely flawed, we dont listen to test tones, we listen to music. music is dynamic and has different levels of bass in the recording that directly affects the head unit pre-out which directly affects amplifier output.

Better way to set gain is via heat tests, play your hardest hitting song, turn it up till it stops getting louder, then back it down a few notches. Play music for 5 mins carefully monitoring the sub and amp for heat and any wierd smells coming out of the sub. If the temperatures are ice cold after 5-10 mins of play time, you are undergained and have a bit more to go. If its slightly above room temperature to mildly hot then its good. If either the sub's dust cap or amp is burning hot, then back it down, either you are clipping or you dont have enough electrical support or there's not enough ventilation for the amp.

So how do you have your current polk facing in the vehicle and how far away from the trunk/hatch is it.

 

[BOOMINGRANDPA 5,000+ posts]

If I end up with too much, I can always EQ it back. Sounds like a good problem to have //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
I'll probably stick with sundown. After hearing my friend demo his and reading up on them I really like the brand and want to give it a try.

SA are very popular here .. as u see from jeff's post i was being nice when i said that ground shaker box was crap lol..

 

[BOOMINGRANDPA 5,000+ posts]

u know about car audio bargain right? perfect new sub may have to much glue on cone or something 30day warranty.. * B-Stock* Sundown Audio SA-12 600W SA Series - Car Audio Bargain

 

[Water Bear]

HORRIBLE BOX fking garbage, never look at sh*t like that again, BURN IT NOW. That is actually closer to 1 cube after displacement. Not 1.75 usable. Its Gross cubic feet meaning before you subtract the space the port and sub takes up. That port is waaay too small as well, might as well have a leaky sealed box. Complete and utter box design fail.
Also if you were using a 0 db test tone with the multi-meter method, you did it wrong and are completely undergained because most music is recorded with -10 db levels of bass so you basically fked yourself out of all that possible output. Thats why the DMM method is completely and severely flawed, we dont listen to test tones, we listen to music. music is dynamic and has different levels of bass in the recording that directly affects the head unit pre-out which directly affects amplifier output.

Better way to set gain is via heat tests, play your hardest hitting song, turn it up till it stops getting louder, then back it down a few notches. Play music for 5 mins carefully monitoring the sub and amp for heat and any wierd smells coming out of the sub. If the temperatures are ice cold after 5-10 mins of play time, you are undergained and have a bit more to go. If its slightly above room temperature to mildly hot then its good. If either the sub's dust cap or amp is burning hot, then back it down, either you are clipping or you dont have enough electrical support or there's not enough ventilation for the amp.

So how do you have your current polk facing in the vehicle and how far away from the trunk/hatch is it.

Hmm so I guess I'll stay away from that box haha

Sub is facing the front, in line with the driver seat, back against the rear bumper. Question, will I get similar results to the run-it-till-it's-hot method using an oscilloscope or similar? Straight nerd here, gotta do it with an abacus or pocket calculator //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

I've been running this set up for many years now, and only recently installed the new head unit. The sub has always needed some extra EQ to be heard. First time I set its gain, I found the resonant freq of my enclosure using audio test tones. I forget what I came up with, but I just cranked the head unit volume and turned up the sub gain till I heard distortion, then back off a bit. Setting gain with the DMM I did get a lower gain setting, but I figured that was just because the new set up was different.

 

---------- Post added at 05:59 PM ---------- Previous post was at 05:59 PM ----------

 

u know about car audio bargain right? perfect new sub may have to much glue on cone or something 30day warranty.. * B-Stock* Sundown Audio SA-12 600W SA Series - Car Audio Bargain

Nope, hadn't heard of them before. Thanks for the info! I like warranties //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[BOOMINGRANDPA 5,000+ posts]

here's the stage 2 box but like i said i'd get it tad bigger .25-.5cf maybe with little lower tuning than this but it shows double baffle and bracing https://www.ebay.com/itm/STAGE-2-PORTED-SUBWOOFER-MDF-ENCLOSURE-FOR-SUNDOWN-SA12-SUB-BOX/263177242776?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D41375%26meid%3D5c5b245bb297433a9911a4a17c320730%26pid%3D100623%26rk%3D2%26rkt%3D6%26sd%3D263177241901&_trksid=p2047675.c100623.m-1

 

[Jeffdachef 5,000+ posts]

Hmm so I guess I'll stay away from that box haha
Sub is facing the front, in line with the driver seat, back against the rear bumper. Question, will I get similar results to the run-it-till-it's-hot method using an oscilloscope or similar? Straight nerd here, gotta do it with an abacus or pocket calculator //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

I've been running this set up for many years now, and only recently installed the new head unit. The sub has always needed some extra EQ to be heard. First time I set its gain, I found the resonant freq of my enclosure using audio test tones. I forget what I came up with, but I just cranked the head unit volume and turned up the sub gain till I heard distortion, then back off a bit. Setting gain with the DMM I did get a lower gain setting, but I figured that was just because the new set up was different.

 

---------- Post added at 05:59 PM ---------- Previous post was at 05:59 PM ----------

 

Nope, hadn't heard of them before. Thanks for the info! I like warranties //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Its much more safe than using any measurement tools. clipping is bad but the MAIN enemy of all electronics which causes them to die is HEAT. Clipping just accelerates heat generation. With audio setups, tools just get you to a generic starting point, but fine tuning and knowing your system's actual limits with EACH AND EVERY SONG you play will be the key factor in keeping your system healthy.

The reason why oscopes and DMMs are useless is already explained in my first post because music has different bass in the recording levels. When you use a test tone, its just a set bass level, either you fk yourself over out of output or you can go deep into clipping and not even know when you play a song with stronger basslines. Most of the times people fk themselves over with severely undergaining along with not knowing the correlation between the basslines in the songs and your actual clean power output from your amps.

That sub orientation is poor, Move the sub 3-4 inches away from the back hatch/trunk lid and fire it towards the trunk. Sealed boxes need a proper loading wall to get loud bass.

The problem with using EQ is, you are introducing a lot of distortion because you are forcing frequencies that are not their in the song to be a lot more present, basically adding bass information to where its not present aka bass boost which is HORRIBLE compared to a proper gain adjustment setting where its just adjusting to the pre-amp levels of the head unit, not introducing distortion and clipping. Gain > EQ/bass boost all day every day.

TLDR: flip the box around put it close to the back hatch/trunk lid as possible, turn off all EQ regarding bass and bass boost. Reset your gains like how I originally stated. DONE~~~

 

[Water Bear]

Its much more safe than using any measurement tools. clipping is bad but the MAIN enemy of all electronics which causes them to die is HEAT. Clipping just accelerates heat generation. With audio setups, tools just get you to a generic starting point, but fine tuning and knowing your system's actual limits with EACH AND EVERY SONG you play will be the key factor in keeping your system healthy.
The reason why oscopes and DMMs are useless is already explained in my first post because music has different bass in the recording levels. When you use a test tone, its just a set bass level, either you fk yourself over out of output or you can go deep into clipping and not even know when you play a song with stronger basslines. Most of the times people fk themselves over with severely undergaining along with not knowing the correlation between the basslines in the songs and your actual clean power output from your amps.

That sub orientation is poor, Move the sub 3-4 inches away from the back hatch/trunk lid and fire it towards the trunk. Sealed boxes need a proper loading wall to get loud bass.

The problem with using EQ is, you are introducing a lot of distortion because you are forcing frequencies that are not their in the song to be a lot more present, basically adding bass information to where its not present aka bass boost which is HORRIBLE compared to a proper gain adjustment setting where its just adjusting to the pre-amp levels of the head unit, not introducing distortion and clipping. Gain > EQ/bass boost all day every day.

TLDR: flip the box around put it close to the back hatch/trunk lid as possible, turn off all EQ regarding bass and bass boost. Reset your gains like how I originally stated. DONE~~~

Gotcha. I think I picked up what you were putting down, thanks for the info!

 

---------- Post added at 08:25 AM ---------- Previous post was at 08:24 AM ----------

 

here's the stage 2 box but like i said i'd get it tad bigger .25-.5cf maybe with little lower tuning than this but it shows double baffle and bracing https://www.ebay.com/itm/STAGE-2-PORTED-SUBWOOFER-MDF-ENCLOSURE-FOR-SUNDOWN-SA12-SUB-BOX/263177242776?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D41375%26meid%3D5c5b245bb297433a9911a4a17c320730%26pid%3D100623%26rk%3D2%26rkt%3D6%26sd%3D263177241901&_trksid=p2047675.c100623.m-1

I think I'm gonna spring for the Stage 2 since it's not much more expensive and seems worth the extra $.

 

[BOOMINGRANDPA 5,000+ posts]

Gotcha. I think I picked up what you were putting down, thanks for the info! 

---------- Post added at 08:25 AM ---------- Previous post was at 08:24 AM ----------

 

I think I'm gonna spring for the Stage 2 since it's not much more expensive and seems worth the extra $.

he has a 30" version as well which is 2.43cf which would give u 2.28cf ad about perfect for sa.. like i said email him ask how much it would cost with rounded port end but without carpet (if u don't care about carpet like most of us) that box would tune u at 35hz after your sub too..