Sloppy subs.

[FullNelson]

I just installed 2 12" Rockford p2s in a ported box, about 4 cubic ft. Powered by a rockford p500-2.

It seems like when it plays double bass it will jumble them together or skip a bass note.

Does anyone know how your suppost to tune these amps?

Or should I just go straight to a sealed box?

 

[Pernilongo]

I just installed 2 12" Rockford p2s in a ported box, about 4 cubic ft. Powered by a rockford p500-2.

It seems like when it plays double bass it will jumble them together or skip a bass note.

Does anyone know how your suppost to tune these amps?

Or should I just go straight to a sealed box?

maybe the port tuning isnt right and makes them play below resonant frequency. and omg 4cuf in a supra, thats like 2/3 of the cabin space. yeah try sealed, but i'm not sure about the subs you have but they just might be not great performers. what are those anyways? i couldnt even find them online

 

[Anth505]

If you took a pair of subs and threw them in a box with 'ports', that is the problem right there.

Ports need to be tuned to the subs, by this I mean the sub determines the size of the box and the diameter and length of the port(s). I am certain that your box is not tuned based on what you said was happening. It likely has nothing to do with your amps.

My suggestion, if you like nice clean tight bass, build a sealed box and be done with it. A ported box will give you a little more volume but it's alot more work.

Oh.....and remember, it's 30% what you buy and 70% how it's installed.

 

[Canuckrz]

I'd recommend separating the 12's into separate compartments if you're going to run ported, its likely that the two subs are clashing with each other over the single port which is why it would cause the bass to jumble together like that. That's what I figure could be partially the problem anyway.

 

[FullNelson]

I just baught the subs and that was the box they came in. and a sealed box is all ready on the drawing board. Thing is when I was testing them in my buddies truck to see if everything worked right, he later connected his subs to my amp and got the same muddled bass. So I was thinking it would be like 80% the tune an and 20% being the ported unmatched box.

 

[radiod]

For the meantime, try shoving some socks or towels in the ports, take up a little bit of the air space. It's always nice giving subs their own air space to work with as well, that way they're not "fighting" for the air movement. I know it might sound dumb, but make sure they're hooked up right with the + -...I've seen fools just about rip their cones off the superstructure by putting one sub the right way and the other sub the wrong way. It can sound like what you're describing too.

And I put my vote in for a sealed box as well...I just typically like the response a heck of a lot better than fighting with port tuning. Just get the size right and you're good

 

[R1GG5]

I think the box choice should go with the type of music you listen to. If you listen to Rap or R&B with slower drawn out base then keep em in the ported box. If you listen to rock like I do then there is no other box than a sealed box, tight response is what you want for rock. Are you sure you were running the proper ohm load on the amp/subs?

 

[pbasil1]

Its the box. Period. The amp is small, and a 2channel. Save up for a mono-block.

The box what makes ~70% of the sound. The rest is the equipment.

Depending on what music you listen to primarily, and how you like your music to sound, will determine what type, and design of box to use. There and many different types of boxes out there. Each has a specific characteristic, as well as a weakness.

Im betting this was a prebuilt box you got from some retailer. The box is very generic and isnt going to sound very good in any environment...

 

[teedoff00]

+1 on the box. Your ports are likely not tuned correctly and you could probably get away with a smaller box. There are subwoofer box designing programs that take into account the crucial sub measurements, (ie. thiel, small, xmax, etc.) if you use a program and properly build the box, it is likely that one of those subs would give you more base than you are already getting and still sound excellent. That being said, if you aren't capable of doing that, go sealed. Although by experience a properly built ported sounds so much better.
Good luck!

 

[Anth505]

I disagree. I have always found sealed to sound better in a car. Ported in the house vs. sealed... I could go either way, but in the car, I think sealed sounds better.

 

[FullNelson]

I agree with the sealed. It will also let me "little amp" put more power to it. I see no need to go with a ported that will only be optimized for a range of maybe 5-10 hz. My music consists of bass notes placed together in more than a 40hz burp every second.

 

[pbasil1]

They both have their pros and cons. And its all going to come down to the end user, and what the music is. Rap and R&B listeners all love ported designs, where as most other listeners enjoy sealed.

Sealed boxes do typically have a tighter and more flat response curve, where as ported boxes have more of a peak for response around the frequency at which it was tuned.

You can have very responsive ported boxes, but the design gets complicated, and typically very heavy.

 

[teedoff00]

A properly built to the sub ported box has excellent frequency response. And the opposite is true for power. You need to amp a sealed box much more to get the same level of "bass" as you would with a nicely tuned ported enclosure.

As to the SQ questions, as with the Supra, it is all in the TUNE.
http://www.diymobileaudio.com/forum/diy-mobile-audio/11192-sealed-vs-ported-sq-myth-fact.html
Long, but makes some very good points.

And more info on types of enclosures, and there + and - 's if your interested.
http://www.the12volt.com/caraudio/boxes.asp

 

[FullNelson]

Well thanks to the posted information above, Im deciding on going with a 4ft^3 box for both subs, they will NOT be divided from eachother. The subs from Rockford say for ported they reccomend a max of 2ft^3, I might go larger and If needed can add wood to make the enclosure smaller.

Also am going to go with removable round ports ranging from 33hz to 45 hz to test which setup me and the subs like best.

Yet to keep port noise down I want to try somehting like 4 4"round ports.

Now 4 4" ports have the same area as 1 8" port, I believe. Which I used in the calculator. Well for the calculator @30hz they want about 32" for the 8" port. Would this be the same as eash 4" port being 8" long?

 

[pbasil1]

No no NO. You need to read my friend! DIY Mobile and Talkaudio.co.uk will have all the info for you to learn.

Building a box is not simple math. It doesnt work that way. A single 8" port is going to reproduce sound completely different than 4 4" ports.Its complicated in how it works. And displacement for the speaker is seperate from the port displacement.

Also, using what rockford reccomends is going to have a very general frequency response. Again, its tuned for playing most anything with average quality and performance. If you listen to just a few types of music, a totally different tune for the box should be done.

If your going to build a ported box, i strongly suggest you do some heavy reading on some good forums.


PS: My avatar, learn to worship it. When you learn what it means, youll know.

 

[Pernilongo]

PS: My avatar, learn to worship it. When you learn what it means, youll know.

I don't get it. what RE audio has to do with it? Am I missing something?

 

[FullNelson]

No no NO. You need to read my friend! DIY Mobile and Talkaudio.co.uk will have all the info for you to learn.

Building a box is not simple math. It doesnt work that way. A single 8" port is going to reproduce sound completely different than 4 4" ports.Its complicated in how it works. And displacement for the speaker is seperate from the port displacement.

Also, using what rockford reccomends is going to have a very general frequency response. Again, its tuned for playing most anything with average quality and performance. If you listen to just a few types of music, a totally different tune for the box should be done.

If your going to build a ported box, i strongly suggest you do some heavy reading on some good forums.


PS: My avatar, learn to worship it. When you learn what it means, youll know.

Ive been a fan or Re audio for a while and had I not got such a good deal on this setup, I would have pieced together a setup from there. Aren't they the company Steve Meade had made famous with his Tahoe?

I will definitely be reading up there. I had not even thought about port size sounding different. I was only thinking in terms of tuning for Hz. :3d_frown:

The whole reason behind the thinking of that box was adjust ability in net volume and port size for Hz to play around with to see what sounds good/best.

By the way, What would you recommend in terms of size/design for this box? Ive heard to tune it to like 35hz for crisp bass for double bass and yet still loud. Feel free to generalize, as I will slowly read up.

 

[Anth505]

My friend, you have been given lots of reading material on the subject and have been given advice from some people who are well educated on the subject. Personally, I have been involved in car audio for around 15 years. When I was younger (and more flexible) i was an installer and helped build a car that won 3rd place novice at the I.A.S.C.A. finals in texas in '98.

I only mess with car audio now for myself and friends/family. I have had all kinds of boxes in my cars over the years and I listen to just about every genre of music. I'm telling you, build a sealed box. For hip hop... build a BIGGER sealed box. It will be a bit boomier. For rock, build the box according to spec and throw some fiberfill in there. The sound will be nice and tight.

It does require more amp power to drive a sub in a sealed enclosure but 1) it sounds better. 2) There is less risk of you blowing the subs 3) It's alot easier.

At the end of the day, if you're not quite sure what you're doing and you don't have the time or desire to read up on the subject just get a professional shop to do it for you, or build a sealed box. You will be more than happy with the results, I promise.

 

[Pernilongo]

My friend, you have been given lots of reading material on the subject and have been given advice from some people who are well educated on the subject. Personally, I have been involved in car audio for around 15 years. When I was younger (and more flexible) i was an installer and helped build a car that won 3rd place novice at the I.A.S.C.A. finals in texas in '98.

I only mess with car audio now for myself and friends/family. I have had all kinds of boxes in my cars over the years and I listen to just about every genre of music. I'm telling you, build a sealed box. For hip hop... build a BIGGER sealed box. It will be a bit boomier. For rock, build the box according to spec and throw some fiberfill in there. The sound will be nice and tight.

It does require more amp power to drive a sub in a sealed enclosure but 1) it sounds better. 2) There is less risk of you blowing the subs 3) It's alot easier.

At the end of the day, if you're not quite sure what you're doing and you don't have the time or desire to read up on the subject just get a professional shop to do it for you, or build a sealed box. You will be more than happy with the results, I promise.

Yeah sealed is the way to go especially when you use subs that are not that great. I think these subs that he is using might not even handle the sealed enclosure. if i'm not mistaken they are really introductory subs and some people say the cone cracks in colder weather and that they just don't play that well period. this needs to be addressed first before going into anything more complicated such as into box design. Although, sometimes it better not to go into helping to build a proper system in some cases. Sometimes they just don't want it. I'm also sticking with my own systems and friends and families Most of the audio shop owners sell products that they will never use themselves, you know, but if the buyer wants a 10 dollar sub in a bandpass box - he wants it, what you gonna do?

 

[FullNelson]

I have been reading, but we all know it takes time. Everything I have learned has been telling me to go sealed. The Rockfrod website lists the Qts as .55, And Ive read anywhere about .5 is sealed territory, Is that right?

Ive also read that polyfill will make the box seem larger than it is, as the air has a longer distance around all the polyfill then in open air. Something like a 10% increase in volume, Just barely noticable.

What is your reccomendations do you have for good drivers? Ive heard the RE XXX are only SPL spakers, are any of the others good?

p.s. I wasnt asking for a system design down to the cut sheet, just a step in the right direction, but I think I've found it.

Thank you guys for your time, and realize how long it took us to learn the Supra, Now I just have to Teach myself this stereo stuff. Ive only had the past few days to start on this stuff, and Im sure you guys know how much there is to learn, And worse yet, how hard it is to learn the right stuff off of the internet.

Again thank you guys for your time and knowledge::salute::