At home, I have a pair of Paradigm speakers that provide a wonderful quality of bass. Very tight, controlled, high impact and loud. Most car based subs I've heard are very vibrational and booming, with very little impact.

Is most of that from the challenges of mounting it way back in the trunk or some such?

Or, and here's my main question, does it have anything to do with the fact that my home speakers are ported, and most car sub boxes are not? What effect would adding a port to an existing box have?

 

Lots of car subs also come ported. Depends on the sub box design. There are basically 3 designs (although there are more):

1 - Sealed enclosure - no ports - they give tight, punchy bass. Very popular for car subs.

2 - Vented enclosure - ported - these have lower cutoff frequency (bass) and can handle more power but will distort quicker below the cutoff frequency. It will sound muddier than the sealed enclosure with the same sub.

3 - Bandpass enclosure - ported with 2 chambers and the sub inside the enclosure - probably the most popular for subs. (at least in bigger cars and home theater ) All the output from this type of design is via the ports. It is called a bandpass because it will only pass a certain freq. range.

Now to answer your question regarding adding a port to an existing enclosure... it will probably make things worse.

If you have a sub and have the Thiele-Small parameters of the sub. (usually comes with it in the box). I can run a couple of calculations for you on all 3.

 

You have to be careful with generalizations about speaker enclosures and the quality of sound produced. One of the problems (as matrix correctly implies), is that different speakers react differently in different enclosures. That's why he asked for the T/S parameters (speaker specs that can be used to determine a speaker/enclosure performance without having to build it).

Some drivers are designed for sealed boxes and perform poorly if vented. Others are made for a ported design, and work best in that type of enclosure.

You'll see speakers advertised as"great in both ported and sealed enclosures". That of course depends on your definition of "great". A speaker optimized for a sealed (or ported) box will by definition not perform as well in the other.

Poor performance is usually in the form of uneven frequency response or higher cut-off (the lowest frequency the speaker can reproduce), or even-worse, under-damping and poorer power handling. Under-damping is what causes the "muddy" sound matrix referred to. For every speaker, there is ONE optimum cabinet design for proper damping. All other designs trade damping for higher efficiency (louder) or lower cut-off (lower bass).

 

well, in all honsetly, a properly tuned and installed subwoofer in a car especially, should not be "tight" or "punchy", it should sound sloppy and rumbly. the tight, or punchy part of the bass should be anchored by your front stage midbasses. if you turn all your speakres out except hte subs, it should have that tight punchy kinda bass, but wtih the midbass anchoring the beginning of a sub note, it WILL have that effect. So basically, what i am saying is that perhaps you should look to improve your midbasses up front. Quality car audio Subs in general, when properly tuned and installed, will do a decent job of providing that low rumbly bass. But if you get a good pair of 6.5" or larger midbass up front and throw decent wattage at them, it will make a decent difference.

if your subs are doing that tight bass, its probably crossed to high. the highest I would EVER go with a sub is 80hz, because beyond that you can start to localize where the sub is and feel that your stereo system is spearkes up front and subs in the back, as opposed to be able to blend in together, it also tends to sound boomy. with most set ups I do, I do not go above 60hz or so on the sub. in my own car, my sub is crossed at 45-50hz, since I have speakres up front that are 8" in diameter and can go down to 30hz if I wanted them to.

when someone complains of bommy bass or "loose bass" I have foudn that the problem, beyond just bad equipment or bad installation, is either subs crossed too high, or the a general lack of midbass up front.

thats my take on the subject.

b

 

Agree with you 100%. Best way to show this is to run all 3 and note the trade-offs.

I agree...if that is what you want...If you want only tight, punchy bass, a single 6.5 will not push enough air because as you state 6.5 is used for midbass and start at the high end of the bass freq. 10s are great for tight bass because the cone is larger, yet can still move quicker than larger subs. Larger subs start getting into the muddier bass...All depends what your goals are. But your point is very valid, could be a midbass problem.


Elistan,
offer still stands if you want the designs. By the way which model do you have at home. I also have Paradigms all the way around for my home theater and am very happy with them.

 

the thing is though, you dont NEED the 6.5" to push enough air to give you all that bass, the point is for a decent 6.5" or larger midbass to ANCHOR the bass note, that initial sound when a tight bass note hits, and when you hve a good blend of the two speakres, you get that nice and tight bass note. a sub by itself should not , and should not be made to sound like that.

b

 

Agree with you 100%, it is there for bass purposes only. Never have it do something it was never meant to do!

 

Okay, here are the details of what I have right now, and my impressions.

All the speakers are BostonAcoustics ProSeries. In the doors, a pair of 6.5s. Behind the seats, a pair of 4.5s. In the trunk, 10.5 sub. And finally, in the A-pillars, a pair of Neo 5T tweeters. The sub is in a custom box, about the size and shape of the depression above the toolkit.

Powering the sub, I have a PhoenixGold XS2300. The manual says it does 300W into 4ohm bridged, and it has an 85Hz lowpass filter. Powering the rest, I have a PhoenixGold Tantrum 400.4.

The XS2300 and 6.5s have been in the car for two years, everything else is new. The headunit is stock.

Now, for how it sounds. At low volumes, it's fine. A little more surrounding than before, because of the rears, and a bit deeper from the sub. But things go nuts when I turn it up much. The highs are way to loud. I can turn the treble way down, then set the volume to where the bass and mids sound good, but if I try to set the treble back to normal the highs are so extreme that it's very painful. If I leave them low, the system ends up sounding muffled. One potential mistake I made - adding the Neo tweeters, rather than just relocating the exist ones from the door to the pillars. When it warms up a bit, I'm going to take off the doors and disconnect the existing door tweeters and see if that cuts down on the high freq volume any. Since the door and pillar speakers are off the same amp channel, I can't adjust anything there.

Basically, I can't get the highs to balance with the lows and mids. Which makes it hard to balance the lows and mids because I can't turn things up much. The bass actually sounds pretty good, although I think it still could use some tuning.

 

What happened to your bass problem? Sounds more like a high problem.

Anyway, first how is everything connected together? You have a four channel amp driving 6 speakers? (The sub has it's own amp).

If you are driving the 6.5s and tweeters (with a separate crossover) on 2 channels and the 4.5s on the other 2 channels, add a resistor to the tweeter to get them to play lower. All this will do is drop some amp power going to the tweeter, making them play lower while your 6.5s have the same amount of power going to them. A 4 ohm resistor will cut the power by about half. Put it inline with the tweeters + lead. You can get these at Radio Shack, just get one that can take a couple of watts. May need a few different values to get it to where you like it. Or if you want to get really tricky, you can get something called an LPAD and mount it somewhere in the car and it will act as a volume control for the tweeters.

If you have the tweeters powered directly from the amp (using the amps crossover) just turn down the gain on the amplifier.

 

[QUOTE]Originally posted by Elistan
[B]But things go nuts when I turn it up much.