| Author |
Thread: Sub sonic filter |
    
Silver Member Username: Johnnylemoine
LaPlace,
Louisiana
United States
Post Number: 145
Registered: Aug-04
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| Posted on Tuesday, October 05, 2004 - 12:50 am: |
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can some one explain exactly why you need a sub sonic filter on when you have a sub in a ported box. What exactly will happen to the sub if the filter is not on? why does it do this? Please explain the mechanics and stuff about it.
Thanks. |
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Silver Member Username: Johnnylemoine
LaPlace,
Louisiana
United States
Post Number: 149
Registered: Aug-04
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| Posted on Wednesday, October 06, 2004 - 07:08 pm: |
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damn, nobody? |
ppi art Unregistered guest |
| Posted on Wednesday, October 06, 2004 - 07:56 pm: |
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the subsonic filter will free up some of you amplifiers power, and may be used to protect a smaller subwoofer incapible of producing hz below 30. |
Gold Member Username: Jonathan_f
GA
USA
Post Number: 2104
Registered: May-04
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| Posted on Wednesday, October 06, 2004 - 07:59 pm: |
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Below tuning, the subwoofer "unloads" from the box, performing as if the box wasn't there b/c the air in the port can't control the cone. This equates to extreme excursion (possibly overexcursion) and if you don't run a subsonic filter, it could result in mechanical damage to the subwoofer. |
Silver Member Username: Audiobahn_man
Freakmont,
MI
Post Number: 156
Registered: Aug-04
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| Posted on Wednesday, October 06, 2004 - 10:12 pm: |
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I have 2 V-Max's and a Sony 1200w amp, in a 4.3 cubic foot box with 1 inch of insulation on each sides tuned to 33 Hz, do i need a filter, my amp already has a low pass set on 110 Hz? |
Juggalo Jeff Unregistered guest |
| Posted on Thursday, October 07, 2004 - 12:42 am: |
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alright ya'll i have 2 10" alpine type r's in a q logic box which can be sealed or ported right now it is ported and the port tubes are to specification 12" inches each my amp has a subsonic filter on it but the level is all the way down are my subs being hurt at all and how do u kno what ur tuning is at |
Gold Member Username: Jonathan_f
GA
USA
Post Number: 2128
Registered: May-04
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| Posted on Thursday, October 07, 2004 - 03:47 am: |
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Steven, a subsonic could probably help you, I'd go w/ about 25 hz.
Juggalo Jeff, depends on what the box is tuned at. 5-10 hz below the tuned frequency usually works well. Better safe than sorry, hard to say whether they're stressed mechanically or not (or ever will be) but as they say "an ounce of prevention is worth a pound of cure". |
Silver Member Username: Audiobahn_man
Freakmont,
MI
Post Number: 158
Registered: Aug-04
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| Posted on Thursday, October 07, 2004 - 03:44 pm: |
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will it make it sound better? |
Silver Member Username: Johnnylemoine
LaPlace,
Louisiana
United States
Post Number: 151
Registered: Aug-04
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| Posted on Thursday, October 07, 2004 - 06:40 pm: |
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alright guys, thanks for your input. |
Juggalo Jeff Unregistered guest |
| Posted on Friday, October 08, 2004 - 12:24 am: |
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how do i kno what my box is tuned at? |
Gold Member Username: Jonathan_f
GA
USA
Post Number: 2149
Registered: May-04
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| Posted on Friday, October 08, 2004 - 01:06 am: |
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Steven, it could possibly if you're having trouble at really low (below say 25 hz) bass tones and your sub is bottoming out at loud levels, but very little music gets that low, so w/ most songs you probably wouldn't notice a difference. The amp will have more power since it isn't having to produce those tones as loudly (subsonics take a LOT of power). But of course, that only applies when the music has that signal on it. Basically, it's more for prevention than it is for sound.
Juggalo, it depends on the size of the enclosure, surface area of the port and port length. Also depends on the subs displacement. |
Juggalo Jeff Unregistered guest |
| Posted on Friday, October 08, 2004 - 01:18 am: |
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well i just have a q logic box with 2 10" alpine type r's(1041d) it is ported right now the tubes are both 12 inches right now which is what the sub calls for and the diameter is 3 inches maybe 4. I believe the box volume is 1.0 cu. ft for each sub |
Silver Member Username: Fishy
Tamarac,
FL
USA
Post Number: 392
Registered: Sep-04
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| Posted on Friday, October 08, 2004 - 01:32 am: |
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If that's one cubic feet AFTER accounting for port and speaker displacement then your tuning frequency is
1) aprox. 47 Hz for a 4" round port
2) aprox. 36 Hz for a 3" round port
Gonna be a lil higher for both if the volume is somewhat less.
-Fishy |
Gold Member Username: Jonathan_f
GA
USA
Post Number: 2155
Registered: May-04
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| Posted on Friday, October 08, 2004 - 01:35 am: |
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I don't know if that 1.0 cu ft volume is net or gross, but you're best off giving me the internal dimensions of the box for each subwoofer. Also, make sure what diameter the port is, an inch diameter makes a huge difference in tuning frequency. |
Gold Member Username: Jonathan_f
GA
USA
Post Number: 2156
Registered: May-04
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| Posted on Friday, October 08, 2004 - 01:40 am: |
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Ok, found your box on Crutchfield. I trust Fishy, and the fact that most prefabs are in high 30s and 40s anyway. That box uses 3" ports, so your tuning is in the high 30s. Subsonic of about 30 hz will work. |
Silver Member Username: Fishy
Tamarac,
FL
USA
Post Number: 397
Registered: Sep-04
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| Posted on Friday, October 08, 2004 - 02:21 am: |
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Oh crap. Trust.
Now I gotta double check.
-Fishy |
Silver Member Username: Fishy
Tamarac,
FL
USA
Post Number: 398
Registered: Sep-04
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| Posted on Friday, October 08, 2004 - 02:25 am: |
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36.27 Hz with 12" long 3" i.d. port in 1.0 ft^3.
-Fishy |
Gold Member Username: Jonathan_f
GA
USA
Post Number: 2161
Registered: May-04
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| Posted on Friday, October 08, 2004 - 02:40 am: |
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I gave you a reasonable margin, high 30s was all I expected of you ;). |
Juggalo Jeff Unregistered guest |
| Posted on Saturday, October 09, 2004 - 02:48 am: |
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yea thats what it is i just have a power acoustik amp and it has the sub sonic filter on it just the dial it goes from 30 hz to 175 hz and i got it all the way down on 30 hz so this is fine right |
Silver Member Username: Fishy
Tamarac,
FL
USA
Post Number: 437
Registered: Sep-04
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| Posted on Saturday, October 09, 2004 - 03:55 am: |
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Yeah, thats probably fine.
I have my box tuned at 28.8 and I run mine about 20 Hz.
-Fishy |
Juggalo Jeff Unregistered guest |
| Posted on Saturday, October 09, 2004 - 10:14 am: |
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aight thanks jon and fishy for all that |
