Have an amp, need to choose a suitable sub.


moniker

CarAudio.com Enthusiast
May 15, 2019
22
2
Hello all, yes this is going to sound very noob.. and I did read the sticky but not sure how else I'd pose this Q!

I posted this in a few other places with no feedback, so really hoping someone here can help!

So I have the Boss PT2200 amp, these are the specs:

2200 W MAX Power 2 Channel
825 W X 2 RMS @ 2 ohm
413 W X 2 RMS @ 4 ohm
1650 W X 1 RMS Bridged @ 4 ohm

I plan on running one sub, bridged.

Narrowed it down between the Rockville K9 10′’, or the K9 12″.  I’d like to power either of these subs somewhere below their claimed RMS capability.

K9 10:

  • Rockville W10K9D4 K9 Series 10" Dual 4-Ohm Car Subwoofer
  • Peak Power Handling: 3200 Watts
  • Program Power Handling: 1600 Watts
CEA Rated RMS Power Handling: 800 Watts

K9 12:

  • Rockville W12K9D2 K9 Series 12" Dual 2-Ohm Car Subwoofer
  • Peak Power Handling: 4000 Watts
  • Program Power Handling: 2000 Watts
  • CEA Rated RMS Power Handling: 1000 Watts
Iv’e been told not to expect anywhere near the claimed RMS output from the amp (1650 bridged), so how much less could it actually be? 1200, 1000, 850?

EDIT: The amp has TWO 25 amp fuses, so tell me (please!) if one of these formulas is more correct than the other:

25amp x 2 = 50 x 14.4v = 720 rms or 25 x 2 = 50 x 10= 500 rms

And what does that mean in the bridged configuration?  Is that formula representing bridging?

Which of these subs do you think might pair best, and how would you configure the sub wiring?

Finally, would this setup warrant upgrading my alternator?  Stock Alt. is 70 amps and the headlights already dim a little bit when the heater fan is on high power.  The only high output alt I've found is 160 amps.  Not really sure how high I'd need to go.

Thank you to any experts who can take the time to weigh in on this!

Product links:

PT2200 - Boss Audio Systems

Rockville W10K9D4 10" 3200w Car Audio Subwoofer Dual 4-Ohm Sub CEA Compliant

Rockville W12K9D2 12" 4000w Car Audio Subwoofer Dual 2-Ohm Sub CEA Compliant

 
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DRBOOM

CarAudio.com Well Known
Nov 21, 2018
249
51
Hey mate, :graduate:

Firstly, I would like to point out that measurements in car are to be taken at 12v hence the 12v negative ground theory.

Regarding your amp, with a 50amp rating, x 12v equals 600watts. Since its a class A/B amp you will be only churning out 300rms of power.( the other 50% of the power turns to heat)

With your Rockville subwoofers,  I suggest you go a single 4 ohm, or dual 2 ohm which would get a 4 ohm load suitable with the amp.

Also go with a ported design box taking the box size factor which would take a lot , if not, all your boot space. :fro: .  Ahhh!! the things we do to get bass and get them girls dancing! :suave:

If you have the amp, use it and you can upgrade later to a more efficient, class D amp mate!

 

THATpurpleKUSH

Smoke weed everyday
10+ year member
Sep 30, 2009
7,339
482
Banging gears and passing queeers
Boss amps only do about 10% of their rated power and the K9 subs all blow up because they are epic piles of shit. You are wasting your money with these cheap over rated brands. You are better off saving more money for better equipment that will last.

 
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Boomin_tahoe

Hurtin' feelings errrday.
10+ year member
Jul 24, 2005
15,312
142
WA
Return that Boss amp and get your $$ back. We can help ya find a MUCH better amp for the $$. Boss is bottom of the barrel garbage. You can get a Soundqubed 850.1 sub amp for about 100 bucks and it'll be 1000x better then that Boss amp you bought.

As for your electrical, do the big 3 and def a bigger alt will help out in your situation. 70 amps is pretty low. You must own a 4 banger little car.

 
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MattinMO

Senior VIP Member
Dec 31, 2017
686
113
St.louis, MO
if you trying to go cheap with sub get a Dayton reference 10", find a local box builder if you cant build one yourself off specs you can pay someone to model and design a box with a cut sheet, as far as amp almost anything would be better then that boss.

Edit: actually the ultimax is on sale cheaper then the reference which imo is a better sub. its actually kind of a steal right not maybe i'll get one...hmmmm

 
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OP
M

moniker

CarAudio.com Enthusiast
May 15, 2019
22
2
Thanks for the input peoples!  Definitely getting the message, and understanding that the Boss is garbage.  Store will only do credit, and they sell mostly household brands.. So going to put that towards my mids.  

My goal was to put something together for around $300 that would thump with at least 800rms.  I researched the issues with the K9 subs, and figured they'd work alright if I kept it under their stated rms handling capability (k9 10 claims 800- give it 600, k9 12 says 1000, give it 800).  Edit:  The last straw (and k9 review) for me;  now lumping rockville in with boss:  




@Boomin_tahoe  Great idea.  I talked with Soundqubed for about 10 minutes today.. They went into so much detail about the amps and helped me get a better technical grasp on things.  Super helpful, very willing to talk about everything electrical, and the amp dyno's as the specs read- [email protected] [email protected]  Currently in the 12v range, so i'll get less, but the big 3 & H/O Alt. + battery & isolator (maybe) is next.  Only thing I don't like about the isolator is the V loss.. Will have to research if there's a way to avoid that.

Also interested in this Skar DDX 12 dual 2  https://www.skaraudio.com/products/ddx-12-inch-car-subwoofer  

RE small 4 cyl car:  It's a 95 Toyota Previa 2.4 4cyl, supercharged, awd, power everything including a rear heater/ac blower (So why did they put a 70amp alternator in it?? Of course the headlights dim with the heater on!)  I'll probably build or find a ported box on the high end of subs CFt range since I have so much open space.  Really leaning towards that Skar sub with the soundQ' amp.  If anyone thinks that is a bad idea, do feel free to share why!

Y'all are rad.  Thanks again.

 
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OP
M

moniker

CarAudio.com Enthusiast
May 15, 2019
22
2
Skar subs are absolute garbage and the owner of the company is a shady rat bastard. Anything but Skar.
I'm willing to hear you out on that... What in particular leads you to make such a statement?  I'm going with some kind of budget sub, and so far iv'e heard good stories of this Skar model lasting quite a long time in daily drivers with high power.  Unlike the rockville subs.  Any power-hungry dvc 2ohm 12'' you would recommend under $200?

 

THATpurpleKUSH

Smoke weed everyday
10+ year member
Sep 30, 2009
7,339
482
Banging gears and passing queeers
I'm willing to hear you out on that... What in particular leads you to make such a statement?  I'm going with some kind of budget sub, and so far iv'e heard good stories of this Skar model lasting quite a long time in daily drivers with high power.  Unlike the rockville subs.  Any power-hungry dvc 2ohm 12'' you would recommend under $200?
Do a simple search on here, there is plenty of info to back it up. I've been a member on here for 10 years, I've seen all the Skar bullshit unfold. There are certain vendors on here that won't sell Skar because of the owner and the way the company is run. 

 
OP
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moniker

CarAudio.com Enthusiast
May 15, 2019
22
2
Okay.. will take your word for it.  Read a couple of complaints of warranty not being honored............Frickn heck man. Made my decision-Getting a sundown SA12 D2 750rms, going to run it hard- full power (after it's broken in) in the appropriate ported box tuned to 35hz.  I just broke my shoulder, so the install is on hold.  Faack.  So much conflicting info in regards to product integrity makes decision making tough!

So this $300 bass upgrade is turning into some real shit...  What it's looking like now:

The boss amp I can't return.....110

Sundown sa12.....200

Soundqubed 850 amp.....100

Appropriate sized, tuned box.....200?

Big 3 upgrade materials including fuses/box.....100?

Amp install materials......40?

Optima Yellow top.....250

H/O Alt.....300

So that 300 project is looking more like 1250+ tax.. What the fack did I get myself into?!  You people are crazy!

 
OP
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moniker

CarAudio.com Enthusiast
May 15, 2019
22
2
Welcome to car audio lol. With that amp a Sundown E series would be fine rather than the SA. And you wouldn't need a HO alt, just upgrade the main batt with a big AGM. 
You wouldn't think I need to upgrade, but my 24 year old van has a 70amp alt, and the headlights lose maybe 30% brightness just by running the heater blower.  idk maybe the vehicle will implode if the heater goes on, windows go up and the brights are on all at the same time. The wiring is stock, never facked with, so nothing hokey going on.  I think Toyota just completely failed on the charging system for this rig..  What is a big AGM  :confused:  

 
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THATpurpleKUSH

Smoke weed everyday
10+ year member
Sep 30, 2009
7,339
482
Banging gears and passing queeers
You wouldn't think I need to upgrade, but my 24 year old van has a 70amp alt, and the headlights lose maybe 30% brightness just by running the heater blower.  idk maybe the vehicle will implode if the heater goes on, windows go up and the brights are on all at the same time. The wiring is stock, never facked with, so nothing hokey going on.  What is a big AGM  :confused:
It would be damn near impossible to even find a HO alt for that vehicle, upgrading the main battery to a group 31 AGM or upgrading the main as large of an AGM as you can get and adding a 2nd AGM in the back along with big 3 upgrade is all the electrical you need for what you are looking to run.

By big AGM I mean something like a Deka 8a31 or XS D3100 or Duracell Platinum group 31. 

 
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BOOMINGRANDPA

WOLFRAM FTW
Jan 8, 2017
7,090
22
NC
u should really watch amp dynos on utube man.. don't buy amp lower class than pioneer 8601 tested 800rms.. no boss planet audio audiotek.. a real 600rms is a huge diff from 180rms that says 2k on it

 
OP
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moniker

CarAudio.com Enthusiast
May 15, 2019
22
2
u should really watch amp dynos on utube man.. don't buy amp lower class than pioneer 8601 tested 800rms.. no boss planet audio audiotek.. a real 600rms is a huge diff from 180rms that says 2k on it
Right.. so after learning about this, i'm looking out for that.  Soundqubed was very insistent on the phone that their amps dyno as the literature reads.. obviously expect less if you can't give it 14v.. So i'll be working on getting full power to it, in time.  He outright said they do not do it like boss and others.  It wasn't a random representative on the phone reading from the catalog, whoever I was talking to was very hands-on in the company.  With that, he said the 850 amp will actually do 900rms @ 1ohm 14.4v, the 1250 put out 1260 @ 1ohm 14.4v.  I think he had first-hand experience with the testing.

What might I get out of these amps with 12.8-13v?  Are these guys completely full of shit?  If so we can get a class action lawsuit going right?

Hard to know who to trust.  Iv'e done my best to go over concerns of less-than-advertised amp power with company techs themselves, and if they are flat out lying to me... at this point that would absolutely incredible.

If you believe Soundqubed is full of it, can you tell me why in technical terms?  My goal is to understand all of this as best I can.  Since diving into this, i've realized I need to know a given amps fusing amperage to get an idea of the real output. 

Thanks.

 
OP
M

moniker

CarAudio.com Enthusiast
May 15, 2019
22
2
RE boss amp, non-refundable said shop owner:

Went back to the shop with the amp, with the understanding I'd receive store credit; walked through the front door and right away the cashier said "put it back on the same card?".  Lol (laughing in my head, rather), "yes that'll be fine".  Apparently, the owner hasn't explained the return policy to all of his floor people.  

 
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THATpurpleKUSH

Smoke weed everyday
10+ year member
Sep 30, 2009
7,339
482
Banging gears and passing queeers
RE boss amp, non-refundable said shop owner:

Went back to the shop with the amp, with the understanding I'd receive store credit; walked through the front door and right away the cashier said "put it back on the same card?".  Lol (laughing in my head, rather), "yes that'll be fine".  Apparently, the owner hasn't explained the return policy to all of his floor people.  
That shop would be out of business fast if they followed the owners version of the return policy. I'm glad you were able to get your money back. 

 
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OP
M

moniker

CarAudio.com Enthusiast
May 15, 2019
22
2
Hello all,

I have returned here to A) vent a little bit  B) Showcase the absurdity in my car audio purchases thus far, especially the latest:  Soundqubed with a big (and surprising) fail.

1)  Bought a BOSS amp, discovered it only puts out less than half of stated RMS, returned after being enlighted by you all.  Thank you.

2)  Bought an enclosure that read ''1.5 cubes @ 34hz", told you guys here on the forum, y'all pointed out that it was likely only 0.7 cubes.  Still waiting for the shipment so I can resell it at a loss on Craigslist or Offer-up.  Burn.

3)  Received shipment from Soundqubed Today.  One 10'' 600 rms dvc sub.  One S1-850 mono amp.  Great sub reviews from people who ran the sub hard for months, maybe years for one particular review, & great amp dyno results on youtube.   Sweet, right?  Not so fast...

Sub packaging:  NO padding or protection on top (cone), and NO padding or protection on the bottom (magnet).  I pick up the package and wonder why it feels so saggy, look underneath and there is a gaping hole in the bottom of the box, the magnet is poking through, exposed to the great outdoors.  What - the - faaack.  Handed the box back to the FedEx guy and signed the refuse-to-accept form.

Amp packaging:  paper padding on only 2 of the 4 sides (D+ for effort?), no padding or protection on the bottom of the package.  Thin amp box (retail box with logos/imagery) to cardboard, that's it.  No visual signs of damage, but considering the entire bottom of the amp had no reasonable protection from the handling during shipping, internal electronics could have taken some beatings.. maybe leading to premature amp failure at some point?  I'd really like to know what you guys think about this one.  Would you return the amp too?  I'm pretty darned sure i'm going to.

This is from the 'returns' section on their website, LOL: 


SERVICE RETURNS:


  • Create an RMA.
  • ****Pack the items(s) well to prevent damage during shipping****.
  • Ship item(s) to us at the address above at your expense.
There seems to be a number of satisfied Soundqubed customers out there, so I'll speculate that they had a new employee in the shipping department, a ding-dong at that.

Every damn time it's something.  Why me, oh why.  Thanks for listening🖐

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