Hi I would like to know does it matter where the port is located on the box (eg. front pannel or side etc.)
Also how much space should there be behind the port and the wall behind it?
I called Alpine Tech Centre and they told me that box dimesions only had to be 1.3 cu/ft with a port 14" long x 4" round. The cu/ft seems kinda small doesn't it for a port enclosure.
Does anybody have any experience with the sound of this sub in a sealed and ported enclosure. Would there be much of a difference in sound going from sealed to a ported design. Right now the bass sounds kinda sloppy in my sealed box and the place where I bought it told me that the Type R performs much better in a ported box.
Currently I have a JBL 300.1 running my sub @2ohms and the box is approx 1 cu/ft
Thanks,
Jay
Replies (14)
LC1 on 07/20/2004 17:26:49
Also one other thing, having two ports 7"long x 4" round would have the same effect as on that was 14" long right?
swez on 07/20/2004 19:10:46
Are you running a 10" sub or 12" sub here? It sounds like a 10" sub in a slightly too large enclosure (sealed). The sloppy bass mentioned indicates too large a box to control the cone. Also, excess Bass boost or Bass EQ will have a similar result.
Say more OK?
Swez
PS Port on front, back sides or top is OK. One diameter of the port (4") is about right distance from any wall surfaces inside the box. You could drop to a smaller port and it would be shorter as well. Consider a 3" port as a possible option if you go ported. Depending on the type of music you like best, tune the port accordingly. Kittle may have some good suggestions on this one as he has done extensive research on enclosure designs to date.
LC1 on 07/20/2004 20:05:47
I am running a single 12" Alpine SWR-1241D. My HU is set to the flat setting with the loudness turned off. My amp crossover is set at approx. 90hz and bass boost is around 2db. The gain setting is around 1/3 the way up. I can't tell you exactly where the settings are on the amp because even I don't know, the knobs don't line up with any of the markings. I had the place where I bought it set the LPF for me.
The guy from Alpine that I talked to said that they recommend using a 1.3 cu/ft box with a 14" long x 4" round port which will give it a tuning frequency at around 35-40hz. He said this set up works best for this sub.
Equipment I'm currently using:
HU: Kenwood KDC-2019 (weaklink is system going to be upgraded in a few months)
Amp: JBL 300.1
Sub: 12" Alpine SWR-1241D
Wiring: 8ga power wire and 12ga sub wire.
Thanks for the help,
Jay
PS: The music I mainly listen to is bass heavy music like rap and house type music. But I also listen classic rock and alternative too.
PPS: Nevermind about the two ports question Alpine said it will not work.
LC1 on 07/21/2004 00:25:09
So I guess what I am try to ask is would there be a big difference in going from a sealed box to a ported one? I don't want to make all the effort constructing a new box and it not be worth while doing it.
Jay
LC1 on 07/21/2004 13:34:05
Anybody have any opions or insights?????
uochronos on 07/21/2004 15:00:17
in my opinion no there wouldnt be but its because i like the sound of sealed boxes. this is more of a opinion then anythign else and you have to decide what you want,,, sealed well give you crisp tight bass and good sq but can be limited on low bass... ported loses some punchyness and a bit of higher end bass but gets the low freq. alot better and deeper also adds about +3db of sound per sub. also the subs well handle less power in a ported box and you well definatly need a subsonic filter to cut out all frequencies below the ports tuning frequency or you well damage your sub eventualy.
swez on 07/21/2004 19:28:26
Agreed... if you like the sound you get in a sealed box now... don't mess with it. The amp mantioned, does not have any SS filters so you would have to buy some to protect your sub from PTF (port tune freq) signals below tuning target.
Sealed subs are nice and tight sounding. They have a natural roll off curve below ~40 Hz and a little EQ boost in that region is fine... If you want a bit more bass. Also, the cabin gain (tranfer function) we get in most car installs, tend to over-emphasize bass below ~60 Hz. This effect gives a nice passive boost to lows in the +15-25dB range, depending on the vehicle.
Swez
PS Besides the added time/costs of building the new box, you'd have to buy SS filters and start all over again. Is it really worth the extra +3dB at port tuned freq? It is if you are competeing in SPL Comps and trying to squeeze every dB you can get from the system. Otherwise... probably not.
Bigeazy4387 on 07/21/2004 21:52:24
swez i have heard by a bunch of people say every 3db's the volume doubles so wouldnt it make all the difference?
LC1 on 07/21/2004 22:14:28
But see thats the problem, I don't really like how the bass sounds. It sounds harsh almost like its distorting but not quite, the bass is not that crisp sounding. And it doesn't matter where I have the gain set because when I turn it up it still sounds the same. I also am not using any boost off my head unit and very little on the amp.
But oh well guess I will just have to live with it until I can upgrade my head unit to a better one.
Thanks,
Jay
uochronos on 07/21/2004 22:35:39
Bigeazy4387 +3db is not much a 3 decibal gain in bass isnt that audible of a differnce especial ate high volumes 130+ however in compitition every last .1 can help you win. and when you compare say using a 1000watt or a 2000watt amp and only gaining 3 decibals of sound but having to redo your entire electrical system that makes a big change that 3 deciabls just cost you 500$ in upgrades or more.
swez on 07/22/2004 08:24:00
Double the power input power to a driver, get a +3dB gain. To double the output you hear, need a +9dB increase in power. A well trined ear can detect a +1.5 -2.0 dB gain adjustment. However, at high SPL levels... above +110dB, the ear cannot really detect the differences well. The ear gets an overload of SPL and tells the brain to block out the excess SPL after just a few minutes of listening.
LC1,
So the bass you are getting now is not where you want it. OK... what size box are you using here and how is the sub wired ohm wise?
The internal dimension (cf) would be great, but if you only have an external dimension, can rough it out math wise to determine the internal cf numbers.
It could be a crossover setting issue, enclosure size is off or HU signal input is not quite there yet. How do you have the sub amp wired for input signal now?
Swez
cplkittle on 07/22/2004 08:30:22
a note on the port question. Front ports have the least cancellation. What type of vehicle are you putting this in? I assume from your login name it is either a corvette or a ~1996 firebird.
LC1 on 07/22/2004 17:56:19
LOL, the LC1 was the begining of the serial number sticker on my monitor at work. Could think of a user name, saw that and used it. However, the car I do drive is a 1993 Plymouth Acclaim.
My box its approx 1 cu/ft, 0.98 I believe it more of an exact number after calculations. It was a store bought box and just to make sure it was perfectly sealed I used some silicone along the seams and around the terminal cup.
My crossover on my JBL 300.1 amp is set about 1/3 of the way up. As I stated before the dials don't match up with the indicator positions on the amp settings. The crossover range is from 32hz - 320 hz. So half way up would be 144Hz and a quater would be 72hz. I have it set about half way between a quater and half.
With my HU its is a Kenwood KDC-2019. Set to a flat setting with the loudness turned off. I know this is a low prepout voltage HU and it could be sending a bad signal to the amp, I dunno.
And my sub is SWR-1241D 4+4ohms wired in parallel to net 2ohms.
Is that the information you were looking for Swez?
Thanks for the help,
Jay
LC1 on 07/22/2004 22:44:53
Also how much space should there be behind the port and the wall behind it?
I called Alpine Tech Centre and they told me that box dimesions only had to be 1.3 cu/ft with a port 14" long x 4" round. The cu/ft seems kinda small doesn't it for a port enclosure.
Does anybody have any experience with the sound of this sub in a sealed and ported enclosure. Would there be much of a difference in sound going from sealed to a ported design. Right now the bass sounds kinda sloppy in my sealed box and the place where I bought it told me that the Type R performs much better in a ported box.
Currently I have a JBL 300.1 running my sub @2ohms and the box is approx 1 cu/ft
Thanks,
Jay
Replies (14)
LC1 on 07/20/2004 17:26:49
Also one other thing, having two ports 7"long x 4" round would have the same effect as on that was 14" long right?
swez on 07/20/2004 19:10:46
Are you running a 10" sub or 12" sub here? It sounds like a 10" sub in a slightly too large enclosure (sealed). The sloppy bass mentioned indicates too large a box to control the cone. Also, excess Bass boost or Bass EQ will have a similar result.
Say more OK?
Swez
PS Port on front, back sides or top is OK. One diameter of the port (4") is about right distance from any wall surfaces inside the box. You could drop to a smaller port and it would be shorter as well. Consider a 3" port as a possible option if you go ported. Depending on the type of music you like best, tune the port accordingly. Kittle may have some good suggestions on this one as he has done extensive research on enclosure designs to date.
LC1 on 07/20/2004 20:05:47
I am running a single 12" Alpine SWR-1241D. My HU is set to the flat setting with the loudness turned off. My amp crossover is set at approx. 90hz and bass boost is around 2db. The gain setting is around 1/3 the way up. I can't tell you exactly where the settings are on the amp because even I don't know, the knobs don't line up with any of the markings. I had the place where I bought it set the LPF for me.
The guy from Alpine that I talked to said that they recommend using a 1.3 cu/ft box with a 14" long x 4" round port which will give it a tuning frequency at around 35-40hz. He said this set up works best for this sub.
Equipment I'm currently using:
HU: Kenwood KDC-2019 (weaklink is system going to be upgraded in a few months)
Amp: JBL 300.1
Sub: 12" Alpine SWR-1241D
Wiring: 8ga power wire and 12ga sub wire.
Thanks for the help,
Jay
PS: The music I mainly listen to is bass heavy music like rap and house type music. But I also listen classic rock and alternative too.
PPS: Nevermind about the two ports question Alpine said it will not work.
LC1 on 07/21/2004 00:25:09
So I guess what I am try to ask is would there be a big difference in going from a sealed box to a ported one? I don't want to make all the effort constructing a new box and it not be worth while doing it.
Jay
LC1 on 07/21/2004 13:34:05
Anybody have any opions or insights?????
uochronos on 07/21/2004 15:00:17
in my opinion no there wouldnt be but its because i like the sound of sealed boxes. this is more of a opinion then anythign else and you have to decide what you want,,, sealed well give you crisp tight bass and good sq but can be limited on low bass... ported loses some punchyness and a bit of higher end bass but gets the low freq. alot better and deeper also adds about +3db of sound per sub. also the subs well handle less power in a ported box and you well definatly need a subsonic filter to cut out all frequencies below the ports tuning frequency or you well damage your sub eventualy.
swez on 07/21/2004 19:28:26
Agreed... if you like the sound you get in a sealed box now... don't mess with it. The amp mantioned, does not have any SS filters so you would have to buy some to protect your sub from PTF (port tune freq) signals below tuning target.
Sealed subs are nice and tight sounding. They have a natural roll off curve below ~40 Hz and a little EQ boost in that region is fine... If you want a bit more bass. Also, the cabin gain (tranfer function) we get in most car installs, tend to over-emphasize bass below ~60 Hz. This effect gives a nice passive boost to lows in the +15-25dB range, depending on the vehicle.
Swez
PS Besides the added time/costs of building the new box, you'd have to buy SS filters and start all over again. Is it really worth the extra +3dB at port tuned freq? It is if you are competeing in SPL Comps and trying to squeeze every dB you can get from the system. Otherwise... probably not.
Bigeazy4387 on 07/21/2004 21:52:24
swez i have heard by a bunch of people say every 3db's the volume doubles so wouldnt it make all the difference?
LC1 on 07/21/2004 22:14:28
But see thats the problem, I don't really like how the bass sounds. It sounds harsh almost like its distorting but not quite, the bass is not that crisp sounding. And it doesn't matter where I have the gain set because when I turn it up it still sounds the same. I also am not using any boost off my head unit and very little on the amp.
But oh well guess I will just have to live with it until I can upgrade my head unit to a better one.
Thanks,
Jay
uochronos on 07/21/2004 22:35:39
Bigeazy4387 +3db is not much a 3 decibal gain in bass isnt that audible of a differnce especial ate high volumes 130+ however in compitition every last .1 can help you win. and when you compare say using a 1000watt or a 2000watt amp and only gaining 3 decibals of sound but having to redo your entire electrical system that makes a big change that 3 deciabls just cost you 500$ in upgrades or more.
swez on 07/22/2004 08:24:00
Double the power input power to a driver, get a +3dB gain. To double the output you hear, need a +9dB increase in power. A well trined ear can detect a +1.5 -2.0 dB gain adjustment. However, at high SPL levels... above +110dB, the ear cannot really detect the differences well. The ear gets an overload of SPL and tells the brain to block out the excess SPL after just a few minutes of listening.
LC1,
So the bass you are getting now is not where you want it. OK... what size box are you using here and how is the sub wired ohm wise?
The internal dimension (cf) would be great, but if you only have an external dimension, can rough it out math wise to determine the internal cf numbers.
It could be a crossover setting issue, enclosure size is off or HU signal input is not quite there yet. How do you have the sub amp wired for input signal now?
Swez
cplkittle on 07/22/2004 08:30:22
a note on the port question. Front ports have the least cancellation. What type of vehicle are you putting this in? I assume from your login name it is either a corvette or a ~1996 firebird.
LC1 on 07/22/2004 17:56:19
LOL, the LC1 was the begining of the serial number sticker on my monitor at work. Could think of a user name, saw that and used it. However, the car I do drive is a 1993 Plymouth Acclaim.
My box its approx 1 cu/ft, 0.98 I believe it more of an exact number after calculations. It was a store bought box and just to make sure it was perfectly sealed I used some silicone along the seams and around the terminal cup.
My crossover on my JBL 300.1 amp is set about 1/3 of the way up. As I stated before the dials don't match up with the indicator positions on the amp settings. The crossover range is from 32hz - 320 hz. So half way up would be 144Hz and a quater would be 72hz. I have it set about half way between a quater and half.
With my HU its is a Kenwood KDC-2019. Set to a flat setting with the loudness turned off. I know this is a low prepout voltage HU and it could be sending a bad signal to the amp, I dunno.
And my sub is SWR-1241D 4+4ohms wired in parallel to net 2ohms.
Is that the information you were looking for Swez?
Thanks for the help,
Jay
LC1 on 07/22/2004 22:44:53
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