Ahh thats because there is none since its not a vented/reflex enclosure, its a sealed enclosure so there is no ports. I opted for it because I personally like the tighter quicker bass it yields compared to the vented or bandpass enclosures (I have had all three types) and though it yields less amount of bass from the same drivers than enclosure types that use ports, the sealed two 10"s inside the cabin is way more than enough already. The other reason is the less airspace needed in its construction since there isn't enough space for the size that is needed for a vented box of two 10" drivers

 

twin 10", less bass, same drivers.

"Tighter quicker bass."

As your 10" speaker cones move forward a vacuum is created within the sealed enclosure, making it progressively harder for the driver to move the cone farther. Conversely, when the driver output reverses and the speaker cone wants to move backwards the vacuum will really help.

With that sort of non-linear drag or damping I really surprised that the level of audio distortion you get isn't more noticeable.

I suspect that a lot of "audio" sins are encompassed in that statement of "tighter quicker bass". What you are most likely hearing is a high level of harmonic distortion of the original content due to inordinately slow forward movement of the speaker cones and then relatively quick return, backward, movement.

But again, there is no "right or wrong" whatever rings your chime.

 

Not quite, I didn't make up those concepts about tighter bass, its a well known standard description of the bass type from the different boxes. Sealed boxes are know to yield what is called "tight" bass and bandpass boxed give more whats called "booming" bass, while vertex is somewhere in between the two. Its really simple, sealed boxes = less bass because there are no resonance ports that increase the bass output, and a bandpass even more so, I have a 10" bandpass that will render your rear view mirror completely worthless from the shaking . And tighter quicker bass because its not as booming due to the vacum shoterning the excursion in time and lengh and no trailing resonance from those ports that increase the output through resonance. Hence sealed boxed are used when you want a "cleaner" bass which actually distorts the bass less, you get more of a sharper quicker kick (tight bass) and less of the longer deeper softer boooom (booming bass).

So you have it the other way around. Thats why sealed boxes are used more for classical music, jazz, blues, rock etc. and vented/bandpass for rap, techno, etc. So one is not better than the other it just depends on how you personaly like your base. But the best way for you to see it is to listen to both boxes on the same stereo and play your favorite tweeking cd's

 

In the mid-fifties I had a neighbor/friend who played the guitar and sang. Except for his redition of Gogi Grant's "wayward wind" I always thought he was better at playing the guitar than at singing. Shows how very wrong one can be.

In any case we added an electronic pickup to has standard guitar but then he came back asking for something "special". I tried several things, even rewinding the guitar pickup at least once, but couln't quite get the sound he was asking for. Later I learned that he had heard another guitar player who had added "fuzz" using a special amp delay line feedback arrangement.

Carlos' sub-woofer arrangement brought that back to mind. I've been setting here being denigrated for suggesting ways to have something close to high fidelity in an automotive environment without knowing that the sub-woofer market has gone elsewhere, "tighter and quicker bass".

One of these days I would like to put a spectrum analyzer on that just to see what, exactly, the statement means.

But, meanwhile, Carlos, and everyone else with these "special" sub-woofers, enjoy the sounds.

 

Going at it again West? ...if you do your research on car audio before you talk you will see that they have nothing "special" and you would know what it actually meant what I said. Unfortunately, is going to continue a mystery to you since I'm not the one to waste my time to explain it to you.

 

First, an admission.

I haven't a clue as to what Carlos, and apparently others, are hearing when they describe bass sounds as "tighter and quicker". Carlos himself has admitted that his two 10" sub-woofers do not perform as "well" as they might absent the poor compliance resulting from the (restricted air capacity) sealed enclosure he is using.

Yet he seeming gets upset if I suggest that two 5" speakers in a tuned enclosure would yield better fidelity and equal volume.

So, this post is only for those of you with an open mind.

COMPLIANCE is a really big word for speaker designers. Basically it reflects a willingness of the speaker cone support structure, inner and outer, to allow the speaker cone to move most easily at the "command" of the electrical current flowing in the voice coil.

In the case of a sealed enclosure with restrictive air capacity the efforts of the speaker designers are wasted. The forward movement of the speaker cone is constrained by the level of vacuum created on the backside due to forward movement. So forward "compliance" is severely contrained. And now when the voice coil current begins to reverse and we have a most willing speaker cone, the vacuum will now help to move the speaker backwards.

Carlos 10" speakers in his sealed enclosure are most decidedly NOT following the commands of the sub-woofer driver amplifier. Now, be-that-as-it-may, Carlos may quite thoroughly enjoy his unique sounds. But to pretend that his system is religiously replicating the original recording is a bit off the mark.

My suggestion would be that if want hi-fidelity sound reproduction, when you go into an automotive audio shop and they start selling sealed sub-woofer enclosures, or anything but sub-woofers mounted in tuned enclosures, or a sub-woofer setup with lots of air space behind (the LS430 uses the entire trunk space), then run the other way, FAST.


And I still stand firmly on my position that the OEM speakers in my 01 C4 or any Porsche Bose system will product much better, higher fidelity, sound reproduction, at equal volumes, bass included, than any system including a really good high fidelity sub-woofer.

So, if you really like listening to Carlos' version of bass reproduction, still, high levels of distortion included, then put down your money and go for it.

 

West, you have no idea what you are talking about, you can't even understand what I say, as you seem to misinterpret everything I say, thats why I'm not even going to bother correcting those in your previous post and neither correcting all the misconceptions and errors of your post bit by bit as I done before. So like I said before do your homework first on car audio and maybe then you will understand why things are the way they are and stop confusing people with your faulty theoretical reasoning and I quote "bla,bla,bla.." without any experience on it. Its as easy as hearing the differnces yourself at a car audio convention/competition or profesional installer shop, but looks like you don't want to do that, and keep contradicting everybody for some reason.

BTW 2x10" sealed is one of the most common subwoofer solutions out there for car audio upgrades due to its advantages among quality sound, ease of construction, versatility of reproduction and smaller space. I would love to take credit for it but its not a personal invention of mine for my particular ear.

I don't know why I even bother replying, everybody else seems to ignore you in this matter by know, I guess I'm slow...

 

Here is some good reading on making bass, subwoofer enclosures, and the benefits and drawbacks of each design. Granted it is from a sub mfg., but it is general enough to apply.


Subwoofer Enclosure Reading

 

Yes, its from a manufacturer but they are great reading, they are quite known and have been around for a long time, I remember going through those over 7 years ago I think.

JL Audio is one of my favorite subwoofeer manufacturers and have a great reputation.



Here is a reference thay make there as to what is refferered as tight bass in sealed enclosure since West has difficulty grasping that concept:

"Transient Response
Transient response refers to the ability of the subwoofer system to reproduce quick changes (transients) in the program material accurately. This is often interpreted as "tightness" or "looseness" which is maybe a dangerous terminology since many people are more influenced by tonal characteristics when asked to qualify the "tightness" of the bass. Transient response is actually a function of accuracy in relation to time rather than frequency. In music, sounds like drum strikes and quick bass guitar pulses are good tests of a subwoofer system's transient performance. A system with good transient response will reproduce these sounds with clear, "tight" definition. A system with poor transient response tends to blur these sounds over time, due to the speaker's inability to stop and start quickly enough to react to the signal accurately.
It is generally accepted that an optimized sealed enclosure exhibits the best transient response characteristics."

 

A little translation in your wording perhaps?

wwest: substitute "transient response" for "compliance".

Carlos: substitute "compliance" for "transient response".

I don't quite see how it is that you are both saying the very same thing but can't seem to understand each other.

And Carlos, I don't know very much at all about the subject but it would appear to me that your sealed enclosure is probably "optimized" to fit your 911, not an "optimized sealed enclosure" as referred to in the article you referenced. Not an expert in any sense of the word but it is really hard for me to believe that there is enough airspace inside your enclosure to allow any reasonable level of transient response, compliance, for two 10" speakers.

 

Theory & practice.

It is a very well known theory, at least in electronic engineering venues, that reducing the gain of an amplifier, or an individual component within, serves to increase the measured bandwidth. To put it simply, the half power points (3db down on the gain/bandwidth plot) are now farther apart, ergo, more bandwidth.

That's what the last powered instrument aboard the Pioneer 10 was set to measure, the HPP of the solar wind. Regretably at about 8 billion miles from the earth we lost contact with it's 10 watt transmitter. But at least we now know that the solar wind's HPP is more than 8 billion miles from the earth. For whatever that matters.

With a sealed enclosure to reduce the 10" speaker's compliance ("GAIN") you have in essence increased their responsiveness, but with regards to bandwidth only. If you were to turn the sub-woofer amplifier's gain/volume up to the point of equal performance to, say, a couple of 5" speakers in a tuned enclosure, you would undoutedly have your ears insulted with the level of distortion created.

 

Juan, thats one of the advantages of sealed enclosures. Sealed enclosures need much less airspace than ported/vented boxes (bandpass need even morte space) and also that airspace needed is not an almost exact figure like in ported boxes, sealed boxes are much more forgiving in that aspect and there is a wider margin of airspace allowed. In this case, there is enough space between the rear seats for a 2x10" sealed enclosure (the space which the driver needs in a sealed box may vary from driver to driver, and the manufacture gives that max and min figure) but not for a 2X10" ported one.

I could have gone with 1x10" ported or bandpass, but I preffer sealed 2x10" which is less efficient box though but in turn you have two drivers of 10" and veryb importantly, at the gain that you can play them inside the car you are not even close ever to getting any distortion (you can trash West's last post again about gain/distortion as you can see... no clue ), also even though the sealed boxes reproduce/perform better at low bass with a quicker transcient response, they don't perform as well as ported in higher bass freq's but if you include 2x6" woofers in the doors, you can't tweek the system for those to start to take over at those freq's (crossovers, etc). Whatever box you fit, you take it into account when designing the whole system to compensate for the disadvantages of each enclosure, so thats why there is no "right" box.

So for the 966, the most popular solutions are 2x10" or 2x8" in a sealed box, but you could also fit a ported box though its construction will be much more difficult since the space behind the seats is very irregularand very limited.