inverted subs in slot ported

I realize my first post is a question. Not the best way to start off but I have browed through the forums for a few months. I've searched for this already and read every post about 8. Basically what I'm asking is this. I have 2 Power Bass 12" 4ohm SVC subwoofers RMS 350. Running on a SoundStream XTA 600.2 Amp. Running in Parallel 2ohm resistance. In a Slot ported box made specifically for the subs. If I was to Invert in a box made just for those subs would I need to reverse polarity since I'm Inverting both subs. But they would be out of phase from my other compnent speakers. 2 Polk Audio 5.25"s in the front and 2 PB xtreme 6.5" s in the back. Also the reason I'm asking about the polarity is because other posts havent exactly been clear on Slot ported boxes most were sealed boxes people inverted in. So since a ported box is made for the air movement wouldn't I then keep the subs pos to pos and neg to neg. Since I'm going to be pushing more air into the box and out of the slot port (in the middle of both of the subs)

We'll it wouldn't let me edit my post above but on a side note this is a 1995 nissan altima SE coupe. Figure I'd let you guys know. Don't know if anyone has done this in a Altima 1995 before or not would love for some tips if anyone has before :)

I'm not a fan of inverted mounts, but yes you should invert the phase (180degree phase). I just checked the specs on your amp and you don't have a phase switch, so yes I'd say reverse the polarity on both the subs.

As for the enclosure being "made" for the subs, you need to know if it was made for a traditional mount or an inverted mount. The volume of the sub is taken into account when designing enclosures, and when you invert a sub you increase the volume of the enclosure. The port is "tuned" using a particular volume of airspace. If you want to keep an inverted mount then you may need to adjust the enclosure volume to get a better sound.

Sealed enclosures typically give you more "wiggleroom" when manipulating the volume and are a lot easier to deal with than a ported enclosure. However a lot of people will say that a properly tuned ported enclosure will kick the s**t out of sealed one.

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Squirrel
"No more Cpt. Kirk chit chat"
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It was made for a Traditional Mount not inverted. Think I should play it by ear and hear how it sounds?

I guess the big question is why are you wanting an inverted mount? Some people believe that you get better SPL, but I personally don't believe you do. Or are you just wanting it for the "look"? A lot of prople bought Audiobahn subs because they blinged out their baskets for inverted mounts.

I would hook everything up normally and listen to how it sounds first. Then invert the subs (remembering to reverse the polarity on both subs) and see if you can hear any difference. If it doesn't sound right after you invert the subs then add some boards to the inside walls of the enclosure to decrease the air volume (compensates for the volume of the sub). If you know the displacement volume of your subs then you can figure out exactly what size boards to use. Otherwise you'll just have to experiment a little (make small adjustments at a time). Remember to use screws and secure the boards, otherwise they will vibrate and cause all kinds of havoc and possible damage to the subs

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Squirrel
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What squirrel says above is correct - the reason your system performs differently is because you've changed the effective volume of the enclosure by inverting the subs - but actually you don't have to change the wiring if both speakers in a 2-sub system are being inverted.  The wiring on the subs can stay the same, although you may have to change the phase of the signal at the amplifier to compensate for total system phase.  But as long as both subs are in the same relative acoustic phase with each other, you can wire them any way you like.

Oh, and as an aside, there is no performance-related reason on earth why someone would want to invert their speakers - although there may be system design reasons why this is done.  But in 99% of the cases, it is only to show off the bling.

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ooo reason...I have had the system for over 2 years :P and I'm about to get some p3's but before that I wanted to invert just to hear how it sounds and if it sounds better then not buy the p3's

I'm a fan of Rockford, I run (2) 12" RF Punch HX2's powered by an RF 1000bd.
Which P3's are you looking at? I'm assuming the 12's since that's what you are already running.

If you decide to go with them, the IMO the best match with your amp is (2) of the 4ohm p3's (P3D412), NOT the 2ohm DVC's. Your amp isn't listed as being 1ohm or 2ohm Mono stable, so by using (2) 4ohm DVC's you have 2 options (actually there are more, but only 2 suite your amp):

1) Wire each in parallel for the 2x300w@2ohm Stereo rating.


2) Wire the subs in series/parallel for the 1x600w@4ohm Bridged rating.


Either way gives you apx. 300w per sub. Since the subs are rated at 500rms you're more than safe. Plus you would have some room for a more powerful amp in the future if you decided to upgrade that too.


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Squirrel
"No more Cpt. Kirk chit chat"
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The amp is 2 ohm stable not 1 ohm I currently have the 2 PowerBass 12's running at 2 ohm Bridged. But yea I see what your saying.

All I had to go off of were the specs from Soundstream (which only rate to 4ohm mono stable). That amp has what they call a "phantom channel" that allows you to run (2) 4ohm speakers in stereo as well as (1) 4ohm sub in mono. I believe it's like a 3.6ohm load or something like that.

If you're running (2) 4ohm SVC's bridged wired in parallel then yea you're at a 2ohm mono load. If the amp can take it then you could go for the (2) 2ohm DVC's wired in series/parallel and hope that it holds out.


If your amp blows then you could always replace it with a mono-block amp that is rated around 1000x1@2ohm like the RF Power 1000bd or JBL BP1200.1

I used to run stereo amps bridged for subs until I discovered mono amps. You can usually get more watts per dollar, and they tend to hold up a lot better under the abuse

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Squirrel
"No more Cpt. Kirk chit chat"
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if you really want to play with bridging amps...


There's about 1320watts there. Each kenwood is a 4-channel amp and the Rockford is a mono. One Kenwood powers the front components as a 2-channel bridged stereo amp, the other powers the rear components as a 2-channel bridged stereo amp, and the Rockford powers the (2) 2ohm DVC's as a mono amp.


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Squirrel
"No more Cpt. Kirk chit chat"
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Show off !!!! :-p ....Im about to get a Cap tommorow and see how that helps my stereo system...I've noticed on hard beats my components distort not because there not good or blown...infact its just the opposite Polk Audio and Power Bass make some fantastic Component speakers Its just I belive the amp pulls so much juice they then dont have enough to power the components if you know what I mean...Any ideas if this can be true or not? and I decided to not Invert the subs on a side note

Forgot to ask is it better to Sit below the Speakers RMS like mine are 350watt 4ohm SVC X2 so 700 watts running on a 600.2 (dual channel amp) so im short about 100 watts and I can get some clipping...or Sit above like say a 800watt amp and not have as much clipping but have a chance to blow the subs...wich is better ?

Caps are ment for voltage regulation, not battery/alternator fixes. They smooth out the voltage to keep a constant SQ level throughout.

Your alternator is rated to produce "x" amount of voltage. The entire vehicle electrical system uses that voltage (lights, ignition, stereo, etc). When the bass hits hard the amp draws more current. The increased current draw pulls voltage away from the other electrical components (like the lights). A cap allows the amp to draw the extra power from it while limiting the draw from the other electrical components. Yes they store juice, but they also need to be replenished. So just adding a cap only adds one more thing that your alternator needs to recharge! If your lights are dimming when the bass hits then odds are you need a larger alternator and possibly a better battery. For the strongest stereo you can have, you need to make sure that there is enough power being produced by the alternator to support it as well as the normal functions of the car!

You should also look into upgrading the wiring from the alternator to the battery, the battery to ground, and the engine to ground. Read the sticky here for more info.

As for the RMS levels, I always try to match the sub(s) and amp(s) as closely as possible.
total RMS of the subs = RMS output of the amp

For example I'm running (2) 500w RMS 1000w Peak subs. The combined subs rating is 1000RMS 2000Peak, so I went with a quality amp producing a reliable 1000w RMS (500/sub). A perfect match in my book.

The largest I would have recommended someone getting with those subs is an amp that puts out 1500w RMS (750w per sub), since the combined RMS is 1000 and half the difference between combined RMS (1000) and Peak (2000) is 500. Although I usually play it safe (since I don't have a lot of $ to throw around if something goes wrong) and stick to RMS matching

If you underpower a sub there is less chance of damaging it, but they usually don't sound quite as good as they would with the correct power rating.

"Clipping" occurs when you have the Gains turned up too high (normally because the amp is underpowering the subs and the user wants more power). Clipping is not a good idea and can damage your amp and/or subs. Make sure the gains are set properly. If it still isn't loud enough then you need a larger amp or a different enclosure.



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Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
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yea the max of the subs is 700 each 350rms each so if i got a 1200amp that would put about 600 each so I should be alright then? And I'll def look into the "big 3" sticy I've heard that term used more then once and wasn't exactly sure what it is. The alternator in my car is a brand new Aftermarket Alternator the ones in the nissan altima stock weren't enough and are a common problem with the Alty so I replaced that as soon as I got the car. As far as ground goes I can easly Replace the ground with a 1 gauge wire to the chassis/Frame. I'll read some more before I post Again and thanks for all the replys :)And the pleasant reply's without flame and Learn to Search etc....I'll be sure to return the favor to others when I learn a little more :)

I think I must have edited that last post at least 5 times because I couldn't get it to sound right *lmao*

To me 600w would be pushing it for a 350w sub. I wouldn't recommend an amp with more than 500w per sub (1000w RMS total). But then again a lot of amplifiers don't even produce the RMS power they are rated at. When they test their amps a lot of companies will use a 14v system (not 12v) to get as much out of the amp as possible. Then they "claim" their amp will produce "x" amount of watts. That's why you see a lot of cheap amps claiming thousands of watts, because they did it on a 14v test block for a split second before they melted!

Glad to help.

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Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
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aww so the 600 is doing alright then im not under watting my subs and damaging them alright good.. and a 1000watt wouldnt hurt them either but would push them a little more and probably break in the cone some more... should i stick to a D grade amp if I upgrade?


also sorry for not using punctuation was smoking a cig at the time.

Also when I say 600 I mean total its a 600x2 so 300 each and 1000x2 so 500 each.

Also done smoking cig now and I can use proper grammar Rofl.

Class D = mono block amplifier (subs)
Class A/B = stereo amplifier (components/cabin speakers)

When I referenced 1000w it was 1000x1@xohms which translates to 500x2@xohms or each sub gets 500watts. Wattage x #channels @ "x" ohms. The rating is how many watts each channel receives. If it's an "x2" like 500x2 then each channel receives 500 watts.

What amp are you referring to? A 1200x1@xohms (which you referenced earlier) would translate to 600x2@xohms (600w per sub, not 300w). This would be too much for a 350w sub IMO.

If you are talking about a 600x1@xohms amp (and not 600x2) then it would be 300x2@xohms or 300w per sub. In this case it's fine. Under powering by 50w is nothing to be concerned about.

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Squirrel
"No more Cpt. Kirk chit chat"
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To put it another way, Class D amps only have 1 channel (mono). All the wattage is split between all the subs on that channel. So a 1000x1@xohm mono amp will always be 1000x1@xohm (and yes if you change the ohm load the wattage will change as well). If I hook up 2 subs to it, then each sub will receive 500w a piece since 1000/2=500.

Multi-channel amps have different ratings because you can have 2, 3, or 4 channels depending on the amp. The rating given for each number of channels is the total wattage each channel receives. For example an 80x2@xohms rating means that each channel will receive 80w when an 'x'ohm load is presented.

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Squirrel
"No more Cpt. Kirk chit chat"
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I just realized that you were still asking about your SoundStream amp lol. Sorry, i got sidetracked.

Your specs are:
150x2@4ohms
300x2@2ohms
600x1@4ohms

You are currently running at a 2ohm Bridged load, which is actually still going to be around the 600w rating, maybe a little more.

So for arguements sake we'll say you are at 600x1@2ohms. Each sub is getting apx. 300w which is a close enough match for (2) 350w subs. You'll be fine as long as the amp doesn't blow from running at too low of a bridged ohm load.

And "yes" if you want to push them a little harder you could go to a 1000x1@2ohm class-d mono-block amp. Just watch the gains and listen for any distortion.

Sorry if there was any confusion, I know I can get long-winded at times lol

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Squirrel
"No more Cpt. Kirk chit chat"
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It's all good the more detail the less there is for id10t problems for me :P. But I totally see what you mean now. I'm possibly looking into getting a new SoundStream amp and possibly some power 2 T2's if im going to drop a load on some new stereo equip. For some reason I just really like 12's. They dont hit some of the higher bass like 10's and not as low as 15's but there just right you know what I mean. And my stepdad has 18's in his porsche. We will just leave it at the fact that. My ears started bleeding in the backseat.

I know what you mean about 12's, they're what I've run for the past 15 years. 10's are excellent for Techno (fast tight bass), 15's are good for ear splitting low bass frequencies. 12's make a nice combination of the two.

The Power T2's are monsters. 1000w RMS and about $800 MSRP. Not to mention finding the right amps to run them. Must be nice to have that kinda scratch to throw around *laughing*

Since you like SoundStream amps, the Picasso series is pretty good. The PCX2000D would suite your "new" needs if you got the 4ohm T2's(T212D4) and wired them to a 1ohm load. That amp is rated 2000x1@1ohm, but I believe it was actually rated at 16v. No clue on what the MSRP would be.

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Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com

Not that I have that much money to throw around. Just work my ass off. I'm looking at either turboing my car atm. Or upgrading the stereo. Looking for a new headunit atm. Trying to find one I could hook a ipod up to or has the ability for me to run a external HD and have it read it.

If you want "nice", check out these Alpine Headunits. I've always been a fan of Alpine and currently run a CDA-7995. It's an older one but I have an adapter hooked up for a direct connection to my MP3 player. I've been running it for the last 6 years and it's still a sweet unit.

Other manufacturers offer similar interfaces. Whether it's a simple phono interface (headphone jack) or and RCA interface (like mine) there are plenty of them out there.

Eclipse headunits get raves too. Their quality is among the best out there.

Nakamichi is also highly sought after.

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Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com