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Sealed vs. Ported and SQ ... Myth or Fact ?

118K views 244 replies 60 participants last post by  chad 
#1 ·
Time for me to stir the pot once again .... He he he ...
I will bet this thread ends up VERY long , and with enough techno babble to baffle Einstien. :D

Here's the skinny : Every day or two , I read where one respected member or another states that ported can sound just as good as sealed , when it comes to tone , speed , blending , and just straight up SQ .... I've heard the BEST ported designs , and I'm just not buying it :eek:
I do feel that ported can sound VERY good , but I have NEVER ONCE heard a ported enclosure that had the transient speed and tone of a great sealed enclosure ..... So here's a thread that should allow everyone to air out their experience , tricks , tips , and technical flim-flam about just how one does go about getting ported to stack up. It needs to be able to play from 80 hz and down , so let's hear it.

Gentlemen , start your subs .... :D
 
#3 ·
Up until recently I was using a pair of 12" MTX 8500s. If you dont know anything about these beasts, they are the MTX equivelant to the JL W7 line. They weigh 50lbs a piece and can handle a lot of power. anywho, I experimented a lot with these subs as far as what enclosure they would sound best in. First I tried your standard spec sealed box and that didnt work so well. then I moved up to a 7.5ft^3 ported enclosure tuned to about 48hz with the subs and the port firing into the cabin of the car (its a sedan). It sounded very loud and thats about it. Then I tried a much smaller ported enclosure (I think it was around 3.5 or 4ft^3) tuned to 32hz with the subs and the port aiming at the rear of the trunk. I really liked this setup and would have kept it if I could just stop imagining other possibilities. The SQ of this setup was amazing for these subs. very articulate and precise. Couldnt have been happier - or so I thought at the time. Next I tried the pair of 12"s in an IB configuration with the subs firing at the back of the rear seats. This was by far the worst setup ever for these subs. the bass was extremely sloppy and the bass response was terrible. it was extremely peaky around 40hz or so. Next I tried an upfiring enclosure with each sub in its own sealed chamber. The subs were firing through the holes in the rear deck where the rear speakers used to be and bouncing of the rear glass towards the front of the vehicle. I was quite pleased with this setup but it was lacking something that I could quite pinpoint that my second ported enclosure had. The SQ was pretty decent but just wasnt as full as the ported design.


Long story short (cliff notes) For those particular subs, the best SQ enclosure that I was able to find was a smallish ported design tuned in the low 30s.
 
#4 ·
you can just get a deeper flatter response with a properly designed ported box. It will roll off lower what a sealed box will al though eq can fix this, and increase output. I have heard both designs sound amazing but its a preference in the tone of the bass. To me ported can still blend and hit like sealed, but play lower flat and louder. I usually try to tune around 27-29 hz but it depends on the woofer.
 
#5 ·
you can just get a deeper flatter response with a properly designed ported box. It will roll off lower. I have heard both designs sound amazing but its a preference in the tone of the bass. To me ported can still blend and hit like sealed, but play lower and louder. I usually try to tune around 27-29 hz but it depends on the woofer.
x2

I am a firm believer in both. The better SQ boxes I have heard use closer to the minimum required box. For example I will use a driver that worked great. It was a Hart Topaz 12 year 93. Not much to the driver and only had to have 150 RMS and 1.5 - 3 cube ported. The driver had a 1watt efficiency of 93 db or something like that. I modeled the box in a 1.5 cube tuned to 40 Hz and it sounded great. It hit lower without any boominess than 2 equivalent 12's in a sealed box and still had the snap of a sealed box.

I believe you can get more out of a ported than you can sealed. The downfall of today is most people that hear ported boxes are either

A. Not built correctly
B. Built for SPL with a +3 db bump or higher


In the past 5 years I have only heard a handful of ported boxes that were built for SQ.

That is why if I am going to port, I use a 10 or smaller, pref an 8. Although I am talking this I am actually going to change to a pair of CDT Audio MS100's that have to have a sealed box just because I have always wanted a set.
 
#6 ·
I thought sealed would yield a flatter response. In my experience, Sealed boxes reproduce a flatter, tighter, less output, less low but blendier type of bass. Ported boxes sound boomier, louder, and deeper bass IMHO.

Also even both at 24db/ slope I found that the Butterworth type x-overs give more upfront bass than L-Riley, anyone else have experience w/ this.
 
#27 ·
There is no best, all situations are different, and each situation dependant on transfer function will sound different based on specific driver in question, targeted response based on box size, not to mention a ported box has many more variables, box size in relation to tuning and vise versa, as well as many many other variables.

I always wonder why people ask what is the BEST thing.......when everyone has a subjective opinion of what BEST is considered, dependant on there own tastes, what they need/want, what they can afford, and 100 other things.......There is no best in anything, when things change consistancy goes out of the window.
 
#8 ·
"It needs to be able to play from 80 hz and down , so let's hear it."

I think that's the key phrase there^^^^^. I have built literally hundreds of enclosures over the last 7-8 years and I have never heard one that could dig down deep and play up to 80 hz as well as a properly built/tuned sealed enclosure.
 
#18 · (Edited)
Thank you Mr. Marv .....
Please allow me to expound on what you said above .... As a shop owner , it simply not pratical for me to try and get people into a system with 4 or 5 amps , dedicated mid-bass drivers that are of the 10" variety , and subs that play from 50hz down ... That's right , true subwoofers that play below 50hz .... Hell , that is easy as pie to get right. But try and get a sub to play flat from 80 hz down to 20hz .....
90% of my customers have systems that need a sub to play from 80hz and down .... and do it well. Transient speed without blurring and overhang .... Crisp , tight , and authoratative tonality ... and low end energy .... THIS is what makes a sub great for me. THIS is not always easy to accomplish from 80hz and down ..... JMO
 
#9 ·
You can still achieve a flat response with a ported box. What I have found to work best in a ported box are basic drivers. I did a pair of Vifa PL 10's in a ported box and they sounded great. I did 4 Dayton 8's the cheap ones for a friend and they sounded great. Not like a JL W7 or Kicker L7 ported enclosures, which in my opinion sound boomy.
 
#14 ·
I'll agree midbass integration is an important factor as I have heard excellent sounding ported set-ups in systems where the midbass could play with authority down below 50-60hz or so but as AVI said and I agree with I have never heard a ported design that could play from 80hz down as well as a sealed enclosure.

That's my story and I'm sticking to it :p :p
 
#13 ·
i have run sealed boxes (or bandpass) always because i believed sealed was the only way to achieve sq.

for fun recently i aquired an 18" sub and built a 6.5 cube ported crx box for it.

it sounds better than my 12w7 in a sealed box?

im officially a convert. ported can sound as good as sealed imo.

maybe better?
 
#15 ·
A sealed enclosure will generally produce a flatter group delay and phase plot. How that's going to translate to an in-car reproduction is unknown in any given application. When you start reflecting off of surfaces your phasing can get quite a bit out of whack as opposed to the originally produced wave.

So when somebody says a sealed enclosure seems to blend better with their front stage, their probably not lying. At the lower end of the ported enclosure's response, the phase will be dramatically different than the upper end (i.e. 80 hz). Now granted, the frequencies that this is starting to happen at, and be very noticeable, are frequencies the sealed enclosure is fighting to reproduce, even with EQ. Now this is a generality, and in essence only valid when all other variables are the same. Like I said before, phasing can get screwed up by all sorts of other variables, and not surprisingly, many of them exist in a car.

So, what does a phase difference equate to. Well, when something is out of phase, that frequency becomes very prominent, or rather stands out. This is pretty common knowledge in the SPL community as it's a trick to get your subwoofer to appear a lot louder. It won't produce higher SPL numbers, but when sitting in the car, it will seem louder. To the SQ person, this can be a problem in that we like our sub's frequency response to blend better with the front stage.

So, what does a ported enclosure provide? Low end extension, and a generally flatter response down to it's low end. By going with a smaller box, tuned low, you can reduce your group delay, and phasing variations. This could account for the difference in "SQ" that you hear. However, you start to lose the low end extension the ported design affords you. It can still be better than a sealed enclosure, so it's an option in many cases. Extended bass shelfs in a car are pretty useless in my opinion for anything that would resemble an SQ installation.

All this being said, it comes down to what you want, and what you're willing to sacrifice. Nothing is perfect, and you just do the best you can, with a lot of trial and error. I've found mid sized ported enclosures, tuned low seem to be the best compromise for me. Take me out of the minivan and put me in a Civic, and that may change real quick.
 
#19 ·
Hmmm.... There seems to be a fair amount of questioning , as to my personal experience with ported subs ..... I have been doing this for 23 years , and have indeed seen some of the best ported designs. I've heard IASCA winning systems with ported subs , and thought they would sound better sealed ;)
If I can tune hundreds of cars per year , and do it well , tell me why I couldn't also tune cars with ported enclosures ? Answer is : I CAN ...
But when that ported enclosure is tuned to it's fullest potential , I still hear things that a sealed enclosure could be doing a better job of , to MY ears.
Probably the very best ported design i have played with to date , was a Diamond Audio D6 12" sub in a small ported enclosure , and tuned to about 31hz ..... It sounded fuggin GREAT !!!!! But when that same sub was placed in a 1.2 cu ft sealed box , it sounded even better :D
 
#20 ·
Guys .... My starting this thread was NOT an attempt to argue with anyone. My opinion is just that , an opinion .....
However , my intent was to start an educating thread .... One that could offer up possible solutions to those of us who would love to see ported designs that impress us ....
I like learning , and often start threads like this , just to see what I can learn. So offer up something of value , but please , quit trying to pick apart my opinion. I'm not here to argue , only to share knowledge.
 
#24 ·
Time for me to stir the pot once again
Here's the skinny : Every day or two , I read where one respected member or another states that ported can sound just as good as sealed , when it comes to tone , speed , blending , and just straight up SQ .... I've heard the BEST ported designs , and I'm just not buying it :eek:
I do feel that ported can sound VERY good , but I have NEVER ONCE heard a ported enclosure that had the transient speed and tone of a great sealed enclosure .....
This thread is simply not going like I pictured it. I think most all of you missed the intent of the thread. So I'm going to stop replying , and just watch and read where it goes from here.
What did you picture, everyone agreeing with you? Arc Audio makes the best amps, Boston Acoustics makes the best sub and sealed is better than ported.
 
#29 ·
Hello gang!
THis is a topic near and dear to my heart, and like Marv, I have probably built a thousand boxes or more since my inception into this mobile audio world.

I'd like to play the Devil's Advocate here and offer a slightly different way to discuss this thread...

We need to look at subwoofer design per era when we discuss this topic, as the best performance in a given enclosure is primarily affected by the drivers chosen. Drivers of today are what has evolved from the push in the mid '90s to build versatile subwoofers with minimal enclosure size requirements so as to fit in our vehicles easier. With the advent of the kicker solobaric and JL Audio W6 series, "all the bass, half the space" was the new direction the manufacturers began to take. The main way to achieve this is How?
Thats right, build stiffer, heavier cones with meatier suspensions, higher moving mass, and massive motors and FORCE the low notes by lowering your Fs.
Jump forward a few years, to about '99 , and we begin to see the trend toward building these same small-enclosure woofers with huge power handling, but now we begin to add higher excursion capability by increasing Xmax (remember when Ground Zero came out with the fat surrounds???) These subs are monsters and the sealed enclosure requirements were miniscule.

With the exception of a very few modern brands, the vast majority of todays subwoofers are geared toward working in a small enclosure simply because thats the direction marketing decided to go. We have a few "multi-purpose" woofers that claim to work well in ported designs , but these subs are sealed first, ported afterthought subs....certainly NOT like Pro Sound drivers or the drivers of yesteryear.

So, when we build a ported box with most of todays subs, even subs that claim to work well in ported designs, we tend to get what I refer to as "sonic slop", this same "slop" we hear whan using a driver with too low a Qts and too low an Fs in an Infinite-baffle setup. Too much overhang, "boomy" notes with little or no resolution of pitch changes, poor transient response, inaccurate attack and decay, I can go on and on. Simply put, very few of todays drivers are built to excell in a ported enclosure, therefore, pitting a sealed design against a ported design in an all-out battle of the Sound Q enclosures would have to be further differentiated by stating "X driver sealed" vs "y driver ported". I know of NO CAR AUDIO WOOFER that is the best of both...do any of you?


So, lets jump back from the dawn of autosound to about the mid '90s, right before the Solobaric desings. We had woofers that had HUGE enclosure requirements. The sensitivity ratings were enormous (remember subs like the IDW, the Rockford Punch and later Power series, the MTX RFL stuff, yadda yadda), yet the vast majority of these subs shared a common item....what was it?
You guessed it! The cones were LIGHTWEIGHT, usually made of treated paper, surrounds were corrugated cloth or foam, and Xmax was MINIMAL. The Fs of these old subs rarely reached 30Hz, if that. Why?
They were based on home audio and pro sound concert drivers, thats why. High sensitivity, huge ported boxes, very dynamic and exceptionally quick. The transient response ability of these older woofers was simply amazing, and yes, they could play up to 80Hz no problem, and often played much higher.
However, people wanted more and more woofers in their cars, and with a Punch Pro 15 needing 4 cubic feet net to sound right, what did people begin to do? They began to look toward companies like Kicker who built Sealed-box-only woofers and figured out with a sub that takes less airspace, you can cram more into the same car , or have more room for a cleaner install.

Yes I am paraphrasing like a mofo. The point is, this topic, at least for me, should be tell us your favorite sealed woofer and why, then your favorite ported woofer and why. Follow me?
Or maybe whats the absolute best sounding subwoofer you have ever personally heard and what enclosure was it in?


Back to the topic----
IMHO,
I feel that there are a few drivers that are absolutely fantastic in a selaed box for SQ, with proper tonal resolution, attack, transient response, no distortion to speak of, and will play cleanly from subsonic to almost 80Hz.

However,

there are a couple drivers that , when placed in a properly-designed ported box, are equal in some areas and better in others, with only ^maybe^ a slight roll-off of the subsonic stuff more quickly than my reference sealed subs.


Shall we discuss specifics here, or what?

Also, what is with the requirement to play a subwoofer up to 80Hz? If we are discussing customers cars off the street who want a good sounding street system, then this topic is not what I thought it was. If we are discussing the uppermost pinnacle of Sound Q utopia, then I argue that in a properly designed system, the front stage should be the dominant factor, and the subwoofer is simply to reinforce the midbass and bottom octaves, NOT to be the primary source of these notes. STRONG midbass presence in the vehicle will be there with a properly-designed and tuned SQ system, and unless the sub is mounted up front, you should never run a sub above roughly 60Hz.
So, do we need some clarification here as to what is expected of this thread?


Sorry for the rambling, its late, and my brain is toast LOL!
 
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#31 ·
The ENTIRE puprose of starting this thread , was to :

#1 - Provoke thought about this much debated topic
#2 - Provide solutions to bring the two camps closer together
#3 - Provide proven data for solutions that work
#4 - Make a database of what subs DO work better ported than sealed

Bassfromspace and Audionutz .... You guys get it. Funny that the two who understand the importance of the potential of this thread , have such zany user names .... LOL
 
#33 · (Edited)
I think the 80Hz mark is hard to acheive as Mr Marv said. I must admit I don't have the technical jargon to back any of my claims up but thought I would throw it out there. I learned alot of knowledge from my installer friends, some of which have been aroud since the early 80s and have seen the changes of car audio, but some things remain the same.

From what I learned and I noticed it from my own experimenting, a ported box plays 1 octave up and 1 octave down fromt he tuned frequency before you start to have issues whether it be frequency response or mechanical noise issues. I don't know the exact name or technical wording for it, but it something like that. For example if you tune a box at 40Hz, it should play down to 20Hz (but thereis a phase shift), and up to 80Hz. Now if you tune it to 30Hz, it SHOULD be able to play down to 15Hz and only up to 60HZ. This is where the problem lies. After 60Hz, the sub will start to sound more mechanical rather then musical. I wish I could explain that better. Anyone want to comment?

I don't know if it's possible to achieve what you want using the following, but a there is a ported enclosure you can build that has two tuned frequencies. What you do is design the box for it's correct airspace, then divide it into thirds. Figure out the port length for the entire airspace at the desired tuned frequency. The sub goes into 2/3 of the airspace and the other 1/3 is separated from the other 2/3. Then you port the 2/3 chamber, the 1/3 chammber and port it between the two chammbers, all with the same port you determined for the entire box. This will produce two tuned frequencies, one at the original desired tuned frequency and another at one octave above. So if you tuned it at 30 Hz, then it also has another tuned frequency at 60Hz. It should allow you to play up to 120Hz then. I just don't know if there is anyway to get the response flat (Maybe EQ?). It's something I have always wanted to try.
 
#34 ·
I'd also like to add as someone else mentioned, most SQ competion vehicles running subs in the rear probably have the subs crossed over below 60Hz if they have a 3way front stage. Once you start going over 45Hz, you run into localization problems IF your car isn't deadened enough to kill resonances. If things are vibrating you are going to be able to tell the sub is in the rear of the vehicle.
 
#35 ·
Sealed vs ported, I think this topic has been discussed and argued many times in ICE forum. I can only says that there's no absolute answer for this question(too subjective arguement). This is more on personal prefrence. But fact is certain sub cannot applied on sealed enclosure(meant for SPL, Rockford's Power series) and some cannot applied on ported(never come across brand yet).
Some websites also stated that their sub is best applied on sealed XX cu value for SQ and ported YY cu for SPL. They even stated that advantages and disadvantages between them.
For my point of view, I prefer use a ported enclosure than sealed. I can always increase or decrease the gain for the sub to suit my preference.
 
#36 ·
The irony is, 15 years ago, people were using sealed boxes for spl. Thinking that they could fit alot more in the area.

Really, this thread rests squarely on the shoulders of current market trends.
 
#37 ·
i think durwood hit a lot of the nails on the head. now i'm about the do a little threadjacking so be gentle.

my memphis hpo is STRUGGLING crossed at 40hz. in every sealed box it's been in it's a 40hz and above wonder. minimum requirement for ported is a cube. how about 1.2 tuned to 30? i mean, my midbass dominates down to about 50hz. then i get mechanical issues with bottoming out. the 24db slopes bring everything together nicely.
 
#38 ·
i think durwood hit a lot of the nails on the head. now i'm about the do a little threadjacking so be gentle.

my memphis hpo is STRUGGLING crossed at 40hz. in every sealed box it's been in it's a 40hz and above wonder. minimum requirement for ported is a cube. how about 1.2 tuned to 30? i mean, my midbass dominates down to about 50hz. then i get mechanical issues with bottoming out. the 24db slopes bring everything together nicely.
xed @ 40?

doesnt leave much for it to do except excurt between 40 and 30 ? no sub is gonna like that.
 
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