Hey Golds and all who frequent!
I't's been a while since I have had time to stop by with summer approaching and Chefing at the Jersery Shore makes for long hours. A few weeks ago I installed a JL 500/1 and a Kicker 10" L7 in a street bass ported enclosure into a friends Galant. The results are awesome and my friend is extremely pleased.(thanks to the knowelage I picked up at CK and all who have helped) I do have a question regarding sonic filter setting on the 500/1. The ported enclosure is 2.25cf and is tuned to an unidentified frequancy. The L7's frequancy responce is 24-100Hz. I currently have the sonic filter set at 30Hz. Can I set the sonic filter to 24Hz for a lower frequancy responce or does it need to be set at the supposed port tuning frequancy of the enclosure. This was a question that came up that I just could not answer. We do not want to harm the sub by trial and error. My buddy likes the low heavy bass so I tuned the amp filter frequancy from 100Hz to 80Hz with good results. It's nice to stop by and post again! Thank You.
Demetrios
Replies (8)
Victor on 06/2/2006 05:50:44
it needs to be set at the supposed port tuning frequency, anything lower than that will burden the sub and may lead to woofer unloading at lower frequencies and high volume..
If you can contact the Enclosure manufacturer and get to know the port tuning frequency then you can set it just precisely..
Another way out , since you know that Vb is 2.25cu ft, and if you can measure the length of the port, if it is a round port then measure then diameter and if its a slot port the measure the height and width... then we can know the Fb ( tuning freq of the enclosure ) , its an equational calculation where if u have some values the other can be derived..
Try and put in a measuring tape , and tell us what it is...
Till then It is adviced not to set the SSF below 30 Hz..
Victor..
demetman on 06/2/2006 11:33:35
Good thinking Victor! This box has a slot port and measures 2 3/8"W, 9 3/4"H and 8 1/4"D at the point where it meets the face of the box. Box dimentions are 33"W X 13 1/2"D X 13 1/2"H using 3/4" MDF. Thanks
Demetrios
swez on 06/2/2006 12:28:06
I'd say you're fine at 30 - 35 Hz., with the SSF. No need to go lower as there is little bass content in most music, below 35 Hz.
The Vb of box is: 2.65 ft^3
Port volume is: 191 in^3 (0.11 ft^3)
Port area is: 0.0282 ft^3
Sub Displacement: 112 in^3
OK math whizzes, convert these details to determine the PTF.
Swez
Victor on 06/2/2006 12:30:58
Ok , those dimensions of the box means that the total internal volume of that box is 2.625 cu ft.
Putting that into the portlength calculator on this page ( this tool is much faster and easier then putting out formulas here, so i am suggesting you use it..)
http://www.carstereo.com/help/Articles.cfm?id=31
first select the type of port, ( square), then enter the number of ports (1), then select (yes) in is it a slot port
then skip the desired tunign frequency and enter the height and width of the port.. as 9.75" and 2.375".
then enter the desired frequency as 30, you will be shocked to see the needed length of the port.. yes... it will show around 21", not enter 40 Hz and it will show you the required length of the port as 9.65, but the length of port in your enclosure is 8.25 so now try entering 42 Hz and you will see that you get the figure of around 8.25 ..
This means that the boz u have is actually tuned to 42Hz... no wonder you cant feel the low end of bass, cause its not present at all, the port filters out those frequencies..
You have set the SSF at 30 Hz, its already way below the permissible limit, i suggest you set the SSF at 40 Hz atleast in order to maintain the health of your sub..
Victor...
swez on 06/2/2006 16:23:20
Thanks for the link Victor and the follow up. Yes, he still should get good low bass at 42 Hz., here. Set your SSF between 35-40 Hz. That will protect the sub from damage.
The low "E" on the bass guitar is about 40 Hz. There are also harmonics that reach higher and lower than the "Consonant tone", but we primarily hear the consonant tone, (40 Hz) and upper 3rd and 5th harmonics.
A 40 Hz test tone, sounds like this: Use MP3 player format
http://www.ronelmm.com/tones/
Swez
demetman on 06/4/2006 00:44:54
Wow guys, I never thought the port tuning frequancy of this enclosure would be 40Hz. The low frequancy responce of the sub is 24Hz so I thought the eclosure would be tuned to a frequancy close to that. Victor, thanks for the port tuning calculator it went to my favorites. Swez, I set the input voltage sensitivity on the 500/1 to a 50Hz test tone you previously sent me. I'll tune the infrasonic to 40Hz and readjust the input voltage sensitivity using the 40Hz test tone. Thanks again for your expertise.
Demetrios
swez on 06/4/2006 09:21:14
Even though a sub has a Free Air Resonance (Fs) of 18,24 or 36 Hz., it does not mean we can expect to hear or feel much of that. If the recording does not have any content in it, we won't hear it.
Also, to get these low frequencies at reasonable output levels, one has to often use a larger ported enclosure than most care to install in a vehicle.
In this enclosure, if you narrowed the vent width only, to say 1.75", and kept everything else the same, the new PTF would be ~37.5 Hz.
To do this, all you need do, is add a panel; 5/8" x 9.75" x 8.25" to decrease the port width inside the box.
Swez
Victor on 06/4/2006 12:16:24
1.75" is decent, but if you go any lower , there will be great chances of port noise.. .
I't's been a while since I have had time to stop by with summer approaching and Chefing at the Jersery Shore makes for long hours. A few weeks ago I installed a JL 500/1 and a Kicker 10" L7 in a street bass ported enclosure into a friends Galant. The results are awesome and my friend is extremely pleased.(thanks to the knowelage I picked up at CK and all who have helped) I do have a question regarding sonic filter setting on the 500/1. The ported enclosure is 2.25cf and is tuned to an unidentified frequancy. The L7's frequancy responce is 24-100Hz. I currently have the sonic filter set at 30Hz. Can I set the sonic filter to 24Hz for a lower frequancy responce or does it need to be set at the supposed port tuning frequancy of the enclosure. This was a question that came up that I just could not answer. We do not want to harm the sub by trial and error. My buddy likes the low heavy bass so I tuned the amp filter frequancy from 100Hz to 80Hz with good results. It's nice to stop by and post again! Thank You.
Demetrios
Replies (8)
Victor on 06/2/2006 05:50:44
it needs to be set at the supposed port tuning frequency, anything lower than that will burden the sub and may lead to woofer unloading at lower frequencies and high volume..
If you can contact the Enclosure manufacturer and get to know the port tuning frequency then you can set it just precisely..
Another way out , since you know that Vb is 2.25cu ft, and if you can measure the length of the port, if it is a round port then measure then diameter and if its a slot port the measure the height and width... then we can know the Fb ( tuning freq of the enclosure ) , its an equational calculation where if u have some values the other can be derived..
Try and put in a measuring tape , and tell us what it is...
Till then It is adviced not to set the SSF below 30 Hz..
Victor..
demetman on 06/2/2006 11:33:35
Good thinking Victor! This box has a slot port and measures 2 3/8"W, 9 3/4"H and 8 1/4"D at the point where it meets the face of the box. Box dimentions are 33"W X 13 1/2"D X 13 1/2"H using 3/4" MDF. Thanks
Demetrios
swez on 06/2/2006 12:28:06
I'd say you're fine at 30 - 35 Hz., with the SSF. No need to go lower as there is little bass content in most music, below 35 Hz.
The Vb of box is: 2.65 ft^3
Port volume is: 191 in^3 (0.11 ft^3)
Port area is: 0.0282 ft^3
Sub Displacement: 112 in^3
OK math whizzes, convert these details to determine the PTF.
Swez
Victor on 06/2/2006 12:30:58
Ok , those dimensions of the box means that the total internal volume of that box is 2.625 cu ft.
Putting that into the portlength calculator on this page ( this tool is much faster and easier then putting out formulas here, so i am suggesting you use it..)
http://www.carstereo.com/help/Articles.cfm?id=31
first select the type of port, ( square), then enter the number of ports (1), then select (yes) in is it a slot port
then skip the desired tunign frequency and enter the height and width of the port.. as 9.75" and 2.375".
then enter the desired frequency as 30, you will be shocked to see the needed length of the port.. yes... it will show around 21", not enter 40 Hz and it will show you the required length of the port as 9.65, but the length of port in your enclosure is 8.25 so now try entering 42 Hz and you will see that you get the figure of around 8.25 ..
This means that the boz u have is actually tuned to 42Hz... no wonder you cant feel the low end of bass, cause its not present at all, the port filters out those frequencies..
You have set the SSF at 30 Hz, its already way below the permissible limit, i suggest you set the SSF at 40 Hz atleast in order to maintain the health of your sub..
Victor...
swez on 06/2/2006 16:23:20
Thanks for the link Victor and the follow up. Yes, he still should get good low bass at 42 Hz., here. Set your SSF between 35-40 Hz. That will protect the sub from damage.
The low "E" on the bass guitar is about 40 Hz. There are also harmonics that reach higher and lower than the "Consonant tone", but we primarily hear the consonant tone, (40 Hz) and upper 3rd and 5th harmonics.
A 40 Hz test tone, sounds like this: Use MP3 player format
http://www.ronelmm.com/tones/
Swez
demetman on 06/4/2006 00:44:54
Wow guys, I never thought the port tuning frequancy of this enclosure would be 40Hz. The low frequancy responce of the sub is 24Hz so I thought the eclosure would be tuned to a frequancy close to that. Victor, thanks for the port tuning calculator it went to my favorites. Swez, I set the input voltage sensitivity on the 500/1 to a 50Hz test tone you previously sent me. I'll tune the infrasonic to 40Hz and readjust the input voltage sensitivity using the 40Hz test tone. Thanks again for your expertise.
Demetrios
swez on 06/4/2006 09:21:14
Even though a sub has a Free Air Resonance (Fs) of 18,24 or 36 Hz., it does not mean we can expect to hear or feel much of that. If the recording does not have any content in it, we won't hear it.
Also, to get these low frequencies at reasonable output levels, one has to often use a larger ported enclosure than most care to install in a vehicle.
In this enclosure, if you narrowed the vent width only, to say 1.75", and kept everything else the same, the new PTF would be ~37.5 Hz.
To do this, all you need do, is add a panel; 5/8" x 9.75" x 8.25" to decrease the port width inside the box.
Swez
Victor on 06/4/2006 12:16:24
1.75" is decent, but if you go any lower , there will be great chances of port noise.. .
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