| memito |
| I have a 12" sub in a sealed box. I built the box to specification for the sub. I thought that sealed boxes were supposed to make the bass have a "punch" to it instead of a "boom". I'm not a big fan of the boominess that subs can produce. Anyways, I stuffed the box with polyfil and the boominess is still there. Is there a way to get rid of the boominess without replacing the box? The box is in my trunk facing towards the back, not towards the front. Someone told me that if I turned the box to face the inside of the car it would help out. Any suggestions? |
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| Bill Fitzpatrick |
Put your main speakers in the trunk as well and then crawl in there yourself.
The sub is in the trunk. . . I can't stop laughing. |
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| sss |
| quote: | Originally posted by Bill Fitzpatrick
The sub is in the trunk. . . I can't stop laughing. |
do u got a better suggestion?
| quote: | Originally posted by memito
Is there a way to get rid of the boominess without replacing the box? |
try to play with the LPF on the sub- amplifier |
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| memito |
| will putting more polyfil inside the box help? |
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| richie00boy |
Not really; adding fill can only make the apparant volume of the box increase by 10% or so, which isn't enough to make a huge difference.
The boominess is caused by any or all of the following:
you have your tone controls set poorly
you have your filters set poorly
the sub is just a rubbish design |
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| djQUAN |
another could be the bass boost on most car amps. if you add some boost. there would be some boominess since it is usually around 40Hz.
I think your crossover is set to around 50Hz or below. increase it to LP at 100Hz or so. which lets the tight bass notes go to the sub. |
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| memito |
| ok, this is what I have on my setup, a hifonics brutus driving a 12" jl. The Hz is at 80 and I added about 6db of gain. This amp has a remote "volume" control, which i don't know if it controls the actual volume or the gain (i've been reading that gain and volume are not the same). So what you guys are saying is that if I go from 80 to 100 on the hz and lower the gain it'll have more of a punch? |
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| Hayden |
could be the sound your playing
is it a test tone or a song? |
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| memito |
| song, I made sure I tested it first with a test tone to set the hz at 80 and the gain i adjusted it by ear... then i popped in a song that has a punchy bass instead of long boomy notes and they sounded boomy |
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| Hayden |
is the box mdf 12mm
whats the modle of the sub |
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| memito |
| no, inches, I thought I put inches. It's a JL 12w6v2-d4 |
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| Hayden |
| your sub will give a little boom in its hits |
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| antiresonant |
| quote: | Originally posted by memito
I have a 12" sub in a sealed box. I built the box to specification for the sub. I thought that sealed boxes were supposed to make the bass have a "punch" to it instead of a "boom". I'm not a big fan of the boominess that subs can produce. Anyways, I stuffed the box with polyfil and the boominess is still there. Is there a way to get rid of the boominess without replacing the box? The box is in my trunk facing towards the back, not towards the front. Someone told me that if I turned the box to face the inside of the car it would help out. Any suggestions? |
If Qtc exceeds 1, you will get a booomy bass - also in a sealed box.
What is Qts, VAS, and free air resonance for this driver? And how big i the sealed box?
I will then explain why you have a booomy bass.
Br.
Vidar |
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| richie00boy |
Whilst in the main you are correct, the Q is only relevant around the resonant frequency. If the box is sufficiently small such that the resonant frequency is high and out of the passband, then it is not of importance. Some car subs with their small boxes operate in this fashion.
If the low-pass filter (Hz as the original poster calls it) is set to 80Hz and finds it boomy, pushing it up to 100Hz will only make things worse.
If the Hz control referred to by the original poster is not a low-pass filter but a bass boost control, try reducing the boost and/or the frequency. |
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| antiresonant |
| quote: | Originally posted by richie00boy
Whilst in the main you are correct, the Q is only relevant around the resonant frequency. If the box is sufficiently small such that the resonant frequency is high and out of the passband, then it is not of importance. Some car subs with their small boxes operate in this fashion.
If the low-pass filter (Hz as the original poster calls it) is set to 80Hz and finds it boomy, pushing it up to 100Hz will only make things worse.
If the Hz control referred to by the original poster is not a low-pass filter but a bass boost control, try reducing the boost and/or the frequency. |
You must have a quite "petite" box in order to get the resonance out of the passband. Imagine a box at only 5 litre, the driver data is Qts 0,3, VAS 50litres, f0 30Hz. With these data you'll get a resonance at 100Hz and a Qtc = 1. How small should we make it - 1 litre? 1 litre result in a Qtc = 2 and a resonance at 200 Hz - only one octave higher.
Higher Qtc also result in a steeper roll-off downwords. The steeper roll-off, the more power is required to maintain the level down to i.a 30Hz. A Qtc=1 means 24dB/oct roll-off - calculate how much power needed at 25Hz to keep the same level as at 100 Hz. 48 dB - means 250 times more power at 25 Hz versus 100 Hz?
Br.
Vidar |
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| richie00boy |
I did not check the driver T/S data. You are of course right :)
Higher Q only affects the slope immediately after resonance. As you get further down it will ALWAYS revert to the same 12dB/oct no matter what the Q. However, the 'affected' slope can often be quite well into the passband even when used in the Under Resonance Principle as outlined in my previous post, so yes it does matter. |
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| memito |
Here are the specs for my sub:
Fs=25Hz
Qes=.480
Qms=7.1
Qts=.45
Vas=79.9 litres
Xmax=.65 in
IW/Im=85.9 dB SPL
Sd=77.8 in²
Re=6.75 Ohms
My box has a volume of around 1.25 ft³ |
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| richie00boy |
Ahh, antiresonant gave me misleading parameters.
By my calculations, you have a Qtc of just over 0.8 and F3 of 40Hz. That shouldn't be particularly boomy.
Play with your tone controls and filters. Set all your headunit levels and tone to zero/flat. 80Hz should be a good starting point for sub low-pass filter. Now set your amp level so you can hear your sub OK, then add a little bass boost if necessary. |
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| Paradise_Ice |
| quote: | Originally posted by memito
ok, this is what I have on my setup, a hifonics brutus driving a 12" jl. The Hz is at 80 and I added about 6db of gain. This amp has a remote "volume" control, which i don't know if it controls the actual volume or the gain (i've been reading that gain and volume are not the same). So what you guys are saying is that if I go from 80 to 100 on the hz and lower the gain it'll have more of a punch? |
Its sound like your subwoofer has a high Q, you will need a smaller box or less air space as it would seem like there is very little loading on the cone, just reduce the internal volume and refit the driver and check the sound again.
With music not a test tone, choose something that has natural sound and not something electronic.
Always Always have your tone controls flat, no bass boost nothing, nada, zip.
The remote gain must be plugged in! or else the amplifier will run at maximium gain and sound terrible.
You have to remember that your car adds gain as well so adding more will give a boom effect, oh boy.
The subwoofer only starts to work at 80Hz so having its crossed over higher a waste of power, as i would hope your normal drivers would be able to cross over well with your subwoofer.
Who does like boom woofers? :smash:
I know, def folk! |
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| djQUAN |
| quote: | Originally posted by Paradise_Ice
The subwoofer only starts to work at 80Hz so having its crossed over higher a waste of power, as i would hope your normal drivers would be able to cross over well with your subwoofer.
Who does like boom woofers? :smash:
I know, def folk! |
so you're saying I'm deaf?
:smash: wel,, I only have two 10's but they go boom when I need them to but they also sound real good when I listen to the right music.
www.djquan.angelcities.com/ride.html |
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| UK1nation |
bloody hell have you more brains than money!!????
CUT A BIGGER HOLE IN THE BOX AND INSULATE IT MORE!!!!
(of course a MONO amp would have been a better choice!) |
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| SY |
| uk, it might be more useful to give the technical information you want to convey without adding the personal stuff, OK? |
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| Spiro007 |
Hi memito.
I ran your speaker and spec through my speaker software. 1.25 ft cube box is ok. it does have a slightly under damped responce but this is good in a box otherwise it will sound very dry. critical damped box would be close to 1.75 CU ft. but you are very close allready so I would not build another box. If you are sounding boomy it may be a number of other factors, Such as placement, poor quility amp wires or inductor if you are using one. also if you are using electronic or passive cross over make sure it is not set too low frequency. the high frequency component of the drum hit is the part that gives makes it sound sharp. I would try running the speaker in home stereo situation since it looks like an 8 ohm speaker.
just to expand on the other factors affecting boom:- extra resistance in the wiring,choke and the actuall resistance in the power amp output stage will actually affect the Qes, Qes is the amount of electrical damping of the speaker, Qes is measured assuming the resistace of the speaker wires, Choke, and amp is ZERO ohms. And this will affect Qts since qts = 1/((1/qes)+(1/qms))
so if your amp output impedance is .25 ohms your speaker wires are .2 ohms and your choke is 0.8 ohms then you have 1.2 ohms. this will increase your Qes from 0.45 to 0.53. which will make your QTS .499. therefore requiring a box of 2.6 cu FT to be critically damped. |
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| Bill Fitzpatrick |
| Just as an experiment, I put a sub in the trunk of my car and then listened to it from the passenger compartment. It did indeed sound boomy. Despite all the advise you have gotten, I still think the problem is having it in the trunk. |
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| Hezz |
MEMITO,
There are probably a combination of things that are causing you to have the boomy bass that you speak of. Some have to do with your speakers and some the amps and some the car itself.
OK, let's start with the speakers. First off, to get punchy bass you need high transient response from the speaker. This is obtained from at least four ways. First the speaker needs to have a powerful and well designed magnet system. Some designs in car audio are more for looks to wow the unsuspecting customer. Also boom is what sells to people in the car audio market. You may wish to find a better speaker from a reputable speaker manufacturer designed to play music. I have not run a box plot on your speaker but generally speakers with high qts like .45 need a very large enclosure to sound good. The closer the total system Q is to .707 which is the critically damped Q the more accurate the speakers will be. Most commercial car stereo subs are designed at around .9 - 1.2 becasue this gives them a bass hump near the bottom of the frequency spectrum.
If you look at Spiros data which is good you will see that in reality you have to include the other parts of the system to estimate the total Q of the driver. It will not really be .45 after wire and corossover and electronic impeadance is accounted for. This is why drivers with qts in the .40 and above range really need larger boxes to work right. 2-3 cubic feet sounds about right to me for a speaker of your specs.
Next the box. The typical car subwoffer box is way and I mean way inadequately designed for high quality bass. The walls are to thin and underbraced. Square boxes are aften used but they have the worst sound because they emphisize one frequency.
There is a lot of vibrational energy wasted into the wood of the sub and if your box is designed like most commercial enclosures that you see in the shops it is inadequately built.
Stuffing the box with dacron will help somewhat because it will break up standing waves inside of the box and remove some of the boxy sound but the improvement is more often heard in the lower midrange where braking up the backwave improves mid bass and midrange clarity.
OK, next is the amplifiers. Car audio amps don't generally generate enough current to take a strong hold of the speaker. Remember that the magnetic field strength is determined by the amount of current that the amplifier puts out. There is a lot of marketing hype in this area to sell watts as if it is the only thing that matters. Unfortunately many manufacturers uses differing methods to rate the amps and they are often highly misleading.
You will also have people telling you out there that all amps sound the same and a watt is a watt. This is pure B.S. There are large, and I mean large differences in how amplifiers sound and how good of bass they have.
You may have insufficient current delivery to your amps by having too small a wire. Both power and ground need to be the same size and of the large size compared to the speaker cables.
Finally the car itself. If you try to put too much bass into your car it will have some tendency so sound boomy just because of the standing waves inside the car. The low bass frequencies are larger in length than your car is so the net result is many flase bass modes. This is a problem with all cars. It is better to size the subwoofers to the car and use powerfull amps and well designed boxes to get that strong tight natural sounding bass that you would like.
Hezz |
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| Bill Fitzpatrick |
| I repeat. The sub needs to be in the car, not the trunk. Didn't anyone actually read his original post? He said he put the sub in the trunk. |
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| Hezz |
MEMITO,
Bill is right. Somehow I missed the most obvious thing. You cannot just put the sub box in your trunk and expect to get good sound. You will have to remove the back seats and create a large opening from the trunk to the passenger compartment. Otherwize you will need to mount the speakers so they fire into the passenger compartment.
Hezz |
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| Paradise_Ice |
Yep i agree, the subwoofer will sound muffled, its like somebody trying to talk with there hands over there mouths, madness.
But when has that ever stopped anybody? |
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| Hayden |
Wouldn’t the trunk make it boomy? I think so
Or try a smaller sub with more power like 10 inch thunder 9500????
or maybe he like his sub? |
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| Hezz |
The simplest why to check to see if the woofers are OK is just to put the box in the back seat for a while and listen.
If necessary the speakers might be mounted on the rear deck if it is large enough. Those speakers are designed to work in rather small boxes and a box can be built under the rear deck of the right size. This is some heavy modification so a lot of guys just put the sub in the back seat if it is not being used much.
There are other things you can do it just depends on how much work you want to do or money to spent and how important good sound is to you.
Hezz |
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| Circlotron |
| quote: | Originally posted by Bill Fitzpatrick
I repeat. The sub needs to be in the car, not the trunk. Didn't anyone actually read his original post? He said he put the sub in the trunk. |
"People light a lamp and set it, not under the measuring basket, but upon the lampstand, and it shines upon all those in the house." ;) |
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| sigops |
Hi guys
you guys seem pretty good with this stuff, i just got a kenwood 10"sub, im just a newbie with this stuff, but i manage to set everything up, just to test it, runs ok
but i never got a box for the kenwood 10"sub
im looking to make my own box,
does anyone know where i could find the schematics for a 10" sub box, thx
I've been looking around everywhere, and just can't seem to find it |
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| owdi |
Are your mids able to keep up with the sub? If they can't, and you have the gains turned up on the sub, it will sound boomy.
You mentioned you have some kind of bass boost, turn it off. Also, check your head unit, make sure all the settings are zeroed out, and your loud button is turned off.
Dan |
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