Sub conumdrum

[mikee55]

Hello Everyone,Can I ask of you,what can I do with the equipment I've got?But first,can you understand the sound I want?I have a budget car system,and yes the moderators will probably push this post into the car forum,but I post here because in part I am asking about a Subwoofer although its use will be in car.Over the past 18 years I have heard varying system sounds from other users who like either a booming thumping or kicking sound that the neighborhood hears.The description of the way it sounds,seems to be "they hit hard" or "kicking",but I use the term"punchy" sound,and I have a quiet chuckle to myself on the many occation,these people turn round and say "yes,I gotta Rockford Fosgate" and the driver has "punch" written on it.These systems provide a bass that I don't like,a continous beat that goes thump thump thump.I assume obviously Dance music and what I hear is the attack or a transient of a Kickdrum.What seems to be missing is any sort of low frequency as the sustain is held then released.Not being a musician,I cant define my meaning well.The initial attack is mostly heard and you either get a "kick" or a "punch" that you feel(sounds like compression to me)so what about the decay?Okay also Reggae,in 1992 I lived up north for the summer,and I must say that the majority of what I heard was from the Coloured guys who seemed to have sorted their sound out.Although their taste is either Reggae or Hip Hop,and although I.C.E was pretty basic back then,I felt air shifting for ages before a BMW drove past and the transient and rest of the system could heard.
So,after moving back down south,I have yet to hear quality bass that you feel.
I have a cheap budget system and can't make up my mind as to Cabinet construction and type.I have a JVC head-unit and an Alpine 2x90w amp that is 2ohm capable,and is bridged and feeding a 12" 4 ohm driver that I got dirt cheap and has a surround thats rubber and fatter than your usual driver.I assumed a large xmax and bought it for that reason.The amp has a 80hz 18dB lowpass filter and when in that mode the amp is bridged.It also has a boost at 50hz appx 6dB if I remember.The box is made of plywood and is appx 40 litres,and is completely sealed.
To my question,how do I get my sound to sound as good as what I described,without buying a better amp,head-unit or speaker.Do I stick with the sealed box,vent it, or bandpass?I can build a better cab,I'm good with wood.And,should I run the amp flat,and build a circuit of my own.If I built a crossover,what frequency should I cross at?Should I use 24dB or more?What eq should I use and then I'd need a bridge circuit because the amp would be out of bridge mode if ran flat.I can build with op-amps etc.Just can't decide what circuit.Also I should mention that there are no Thiel/Small parameters with the driver.
Sorry its long winded,but what are your thoughts,please.

Mikee55

[BassAwdyO]

Is this bass quality you are describing INSIDE or OUTSIDE the car?

Just about any decent sealed setup will have ~flat(I say ~flat because in a car environment there are many peaks and dips, but the boost of cabin gain will match the sealed rolloff well for low frequencys) So its probably the boost at 50hz that is adding too much punch and not enough of the resonant.

[Cal Weldon]

Hi mikee55,

On top of what BassAwdyO said,

The fat surround woofers are made for depth of bass, not punchiness. If you want punch and not a tickle under your seats, try a PA woofer. More than deep enough for a car, built tough and nothing seems to touch them for that punch. Oh, and did I mention they're efficient? Much more so than your 12" fat cat. You might not need anything more.

[BassAwdyO]

I think what mikee was saying is that he wanted more of the boom after the kick than the initial punch.

To me that says 6th order bandpass all the way... Tune the rear chamber low(for car audio) between 25-30hz and the front chamber between 60-80hz

You really need the T/S parameters though if you want to make this decent.


To me, it sounds like you spent less than $200 on the woofer itself and IMO you should probably look for a new one.

I myself have been very intrigued by the idea of using PA drivers in a car environment also. The efficiency is definately a PLUS PLUS when in the car audio realm, but enclosure size is the biggest downside.

My suggestion would be an "IB" between the trunk and cabin. This gives you pleanty of volume behind the woofer and takes up minimal trunk space. Of course if you're in a hatchback or something then that might not work, but a single 18" PA driver with 96+db @1w/1m would surely give you an incredible amount of bass in your car

[simon5]

I think you should go with a large sealed box.

Try to remove that 6 dB boost in your amplifier.

[lndm]

I think you are saying you want the music to sound more real than some car systems you have heard. I would agree most with the closed box, maybe vented if your woofer prefers. I would not use a bandpass enclosure for accurate sound.

Also, try making your box stronger/more solid than is common.

[mikee55]

Interesting replies,Hi All,no I'm definately NOT after "punch"! The improvement in the cab design and construction will help.The lack of T/S parameters is a pain,the driver was built by SplX.Have considered measuring meself,but wondered if software would be up to the task on my 24bit Creative soundcard.Nothing beats accurate test gear!Also,my car is a hatchback so I gotta use a box.I don't use the 50hz boost,and if I've got a issue with the peaks and dips,how about a 24dB linkwitz lowpass,(what freq?) Rod Elliotts Sub EQ,8 band I think he does,with constant Q or something and then a bridge circuit to bridge the amp?

Thanks for your input.Mikee55

[mikee55]

Forgot to add,the car is a small hatchback,and I'm after a sound that feels like walking through a Fog of sound and has no kick just a nice extension.I know a weak link is power.And definately having no T/S parameters is making it difficult.
Cheers.Mikee55

[BassAwdyO]

Crossing at 80hz isnt helping... I'd suggest below 50hz

[mikee55]

Hi,just had a drive in the car without listening to the mains.The sound is terrible,loud but thin.Something is seriously missing.Sounds like my head is in a plastic bucket,I have a kick drum physicaly hitting me,and a bass guitar that has no body or warmth.I have to add that theres no stuffing in the box,have tried to stuff with a duvet,but couldn't get the right sound either.I think I need to build a better box and try and measure the speaker's T/S.It also sounds like I have some freqeuncies louder than others.This must be the cabin issues,peaks and dips etc.
Cheers.Mikee55