okay just for my knowledge what is the proper way to set a ssf how do you determine wher to set it at
thanks
Replies (10)
cplkittle on 07/22/2006 10:29:37
Unless you have an enclosure that is ported and tuned to 22-25Hz, most SS filters are set to around 20Hz. now this is not going to cut out ALL frequencies immediately below 20 Hz, there is a slope and most of the time your amplifier manual will tell you that it is a 12dB/octave, 24dB/octave etc.. basically an octave is 1/2 the frequency. one octave down from 20Hz is 10 Hz, so a 12dB/octave slope would mean that 10Hz is 12dB quieter than 20Hz.
There is no right or wrong way to set it unless you just simply turn it off.
The average human ear can only hear down to around 18Hz, so anything below that is just wasted movement for the speaker and wasted power from the amplifier as well. Tell me what kind of box, subs, vehicle you have and I can help you a little more as to what to consider a proper setting.
swez on 07/22/2006 10:53:03
This is a tough question to answer well. I have searched the Web for over an hour and cannot find any comprehensive information on infrasonic filtering. (Commonly call Subsonic Filters)
The original application for this filter was to remove unwanted turntable rumble/noise due to warped vinyl LP's. (Ie: Records, vinyl discs with music etched into grooves, a record player with a stylist type pickup device, commonly used in the pre-CD days) Ask your parents about them as this is all we older folks had pre-1980's
Anyway, the Infrasonic Filter is used to:
1. Removes low frequency noise that robs amplifiers of clean power
2. Prevents subwoofers from excess excursion as they receive amplified bass frequencies
3. Filters out undesirable, very low frequency signals for port tuned sub applications (sub protection filter)
Have noted that most quality mobile audio amplifiers have some sort of Infrasonic filtering available. The basic filter is either at a fixed frequency, (say 15 or 20 Hz.) dual fixed settings, (15/25 Hz.) and variable filtering that ranges from 45 Hz., and lower are also available.
Which is best? The one that works!
Meaning, when your subs are playing very low signals at high amplitude levels, (High SPL Bass) the cone does not go "spazzing out" with total loss of mechanical control and begins to oscillate wildly, but producing little audible sound. These events are very hard on any subwoofer. Why? The cone does not move in and out adequately to cool the voice coils. Hense, a fried coil, fractured motor components or tinsel lead pull outs.
Intuitively, it makes sense to use a filter that blocks low bass frequencies just below port tuning frequency of the sub enclosure. However, we also need to consider the filtering slope characteristics too.
Some basic infrasonic filters will provide (-12/-18/-24) dB/octave filtering slopes. The higher the number, the better the filter will work at blocking low frequencies. (Frequencies at and below stated cutoff point)
For now, the best advice I can give to all, is to watch the cone movement and check the heat generated by the sub as we run low frequency test tone sweeps. If we note limited cone movement, (In and out excursions) smell over-heated coils, or hear cone "brapping", this is a good indication a filter is needed or the filter used is not adequate for a given sub/enclosure design.
Hope that helps somebody here,
Swez
PS Many of the newer high SPL subs have very strong suspensions, large voice coils and efficient motor functions. They can take more abuse and come back for more. We know we have one of these subs if the reference efficiency values are below 85dB SPL @ 1 watt/1 meter.
cplkittle on 07/22/2006 13:58:05
outstanding reply, swez.. I love the brief history behind any topic, makes you look at it from a whole new point of view.
Ash on 07/22/2006 14:22:53
Very thorough guys! CLAP
That is basically what I do.
I take a bass song that has some pretty strong low notes. Then at a medium volume (not high as to cause damage before setting), I listen and watch the sub's cone for excess movement without further output. While consistently playing that part again I raise the frequency of the filter until the flutter is reduced to a minimal level that does not affect higher notes output. If you look at the dial it should not be that far off from where you port tuning frequency is. The dial # positions are not always as accurate so the latter should not be the sole instruction.
It's not as tricky as it sounds, in fact, you will be able to clearly tell when the bass cleans up.
raulbustos on 07/22/2006 15:27:28
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9744236917&rd=1&sspagename=STRK%3AMEWN%3AIT&rd=1
this is the sub and box combo that will be set up uzing an a180001dt its under there class d line http://www.audiobahn.com/Audiobahn06/pages/amps.html
and the subs AWES12P the eternal line
http://www.audiobahn.com/Audiobahn06/pages/woofers.html
swez on 07/22/2006 22:32:41
I take it you mean the A18001DT id the amp you are looking at? (1800 watts RMS @ 1 ohm)
"Hold on to your lug nuts... it's time for an overhaul" SMILE
Man, your trunk is gonna have more chrome in it than my old 1970 Pontiac Grandville. hehe (455 CID, 300 HP, Dual exhaust and 750 CFM Holley Carburator did)
Looked like these, but was a 2 door Hardtop:
http://www.classicpontiacs.com/seventies/b-bodies/1970/index.html
Swez
raulbustos on 07/24/2006 01:02:38
yeah that is the the amp but how would i know what the port is tuned at or should i just use my ears to determine where to set it at all im woried about is setting it to low and having the subs unload and the subs blow and since this isnt my stuff i like to take extra care in adjusting the amp see me personaly i allways use a sealed box so i never have to worry about port frequencys and i just set the ssf by whaere i like it and think it sounds good .
ps my verry first system that i had was stolen out of my car when i was in highschool this was the first thing that i ever had stolen from me the whole thing allmost made me give up car audio all together but that only lasted about two months after i got tired of listening to my engine for entertainment. it was an old (well brand new then) sony mobile ES set up and they took every thing my hu front and rear speakers four chanel amp mono amp and my two 10s and custom box and not to mention broke a $500 back window it was in a 88 camarro in all and all i think i lost about $3000 but it was defenatly a learning experience
swez on 07/24/2006 10:28:27
You might need to contact Audiobahn and ask them about the tuning frequency of that sub enclosure. My guess, it will be between 40-45 Hz. Confirm that OK?
You can do a good job of dialing in your SSF settings by ear and just watching the cones as you tweak. You know you are at the right SSF settings when the bass is clean and strong and plenty of air coming out of the port, but sub cones are behaving well.
FYI: When we get near the port tuning frequency, most bass energy comes out of the port and the sub cones don't move as much. If we go below port frequencies, the sub comes unload, become somewhat erratic and very little bass comes out of the port/vent.
That is hard on subs as the motor system becomes over-loaded and cannot adequately control the motion of the cones.
Swez
raulbustos on 07/24/2006 14:21:26
ah well see he dint buy it from audiobahn he got them from that link that i posted off of ebay
also do you know of where i could get a test tone that would cover these frequences
swez on 07/24/2006 19:53:40
Try NCH tone generator software off the Internet. This is a free service and has some decent tools for the serious audio enthusiast. Just browse the files and set up test tones you like for use with Windows Media Player.
Bass tones: 30, 40,60,80 & 100 Hz.
Midbass: 150,250 & 400 Hz.
Midrange: 500, 750, 1,000, 2000 Hz.
Highs: 2,500, 4,000, 8,000, 12,000, 16,000 & 20,000 Hz
Pink Noise is very useful for balancing and dialing in all audible frequencies. It is basically all frequencies blended into a full range signal that sounds like an FM station that has very low signal or off frequency.
http://www.world-voices.com/software/nchtone.html
This requires purchasing a license to get the full features available. Free to try, use it often, than buy.
This one is more complex but very interesting features:
http://www.softplatz.com/Soft/Education/Science/15120.exe
Swez
thanks
Replies (10)
cplkittle on 07/22/2006 10:29:37
Unless you have an enclosure that is ported and tuned to 22-25Hz, most SS filters are set to around 20Hz. now this is not going to cut out ALL frequencies immediately below 20 Hz, there is a slope and most of the time your amplifier manual will tell you that it is a 12dB/octave, 24dB/octave etc.. basically an octave is 1/2 the frequency. one octave down from 20Hz is 10 Hz, so a 12dB/octave slope would mean that 10Hz is 12dB quieter than 20Hz.
There is no right or wrong way to set it unless you just simply turn it off.
The average human ear can only hear down to around 18Hz, so anything below that is just wasted movement for the speaker and wasted power from the amplifier as well. Tell me what kind of box, subs, vehicle you have and I can help you a little more as to what to consider a proper setting.
swez on 07/22/2006 10:53:03
This is a tough question to answer well. I have searched the Web for over an hour and cannot find any comprehensive information on infrasonic filtering. (Commonly call Subsonic Filters)
The original application for this filter was to remove unwanted turntable rumble/noise due to warped vinyl LP's. (Ie: Records, vinyl discs with music etched into grooves, a record player with a stylist type pickup device, commonly used in the pre-CD days) Ask your parents about them as this is all we older folks had pre-1980's
Anyway, the Infrasonic Filter is used to:
1. Removes low frequency noise that robs amplifiers of clean power
2. Prevents subwoofers from excess excursion as they receive amplified bass frequencies
3. Filters out undesirable, very low frequency signals for port tuned sub applications (sub protection filter)
Have noted that most quality mobile audio amplifiers have some sort of Infrasonic filtering available. The basic filter is either at a fixed frequency, (say 15 or 20 Hz.) dual fixed settings, (15/25 Hz.) and variable filtering that ranges from 45 Hz., and lower are also available.
Which is best? The one that works!
Meaning, when your subs are playing very low signals at high amplitude levels, (High SPL Bass) the cone does not go "spazzing out" with total loss of mechanical control and begins to oscillate wildly, but producing little audible sound. These events are very hard on any subwoofer. Why? The cone does not move in and out adequately to cool the voice coils. Hense, a fried coil, fractured motor components or tinsel lead pull outs.
Intuitively, it makes sense to use a filter that blocks low bass frequencies just below port tuning frequency of the sub enclosure. However, we also need to consider the filtering slope characteristics too.
Some basic infrasonic filters will provide (-12/-18/-24) dB/octave filtering slopes. The higher the number, the better the filter will work at blocking low frequencies. (Frequencies at and below stated cutoff point)
For now, the best advice I can give to all, is to watch the cone movement and check the heat generated by the sub as we run low frequency test tone sweeps. If we note limited cone movement, (In and out excursions) smell over-heated coils, or hear cone "brapping", this is a good indication a filter is needed or the filter used is not adequate for a given sub/enclosure design.
Hope that helps somebody here,
Swez
PS Many of the newer high SPL subs have very strong suspensions, large voice coils and efficient motor functions. They can take more abuse and come back for more. We know we have one of these subs if the reference efficiency values are below 85dB SPL @ 1 watt/1 meter.
cplkittle on 07/22/2006 13:58:05
outstanding reply, swez.. I love the brief history behind any topic, makes you look at it from a whole new point of view.
Ash on 07/22/2006 14:22:53
Very thorough guys! CLAP
That is basically what I do.
I take a bass song that has some pretty strong low notes. Then at a medium volume (not high as to cause damage before setting), I listen and watch the sub's cone for excess movement without further output. While consistently playing that part again I raise the frequency of the filter until the flutter is reduced to a minimal level that does not affect higher notes output. If you look at the dial it should not be that far off from where you port tuning frequency is. The dial # positions are not always as accurate so the latter should not be the sole instruction.
It's not as tricky as it sounds, in fact, you will be able to clearly tell when the bass cleans up.
raulbustos on 07/22/2006 15:27:28
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9744236917&rd=1&sspagename=STRK%3AMEWN%3AIT&rd=1
this is the sub and box combo that will be set up uzing an a180001dt its under there class d line http://www.audiobahn.com/Audiobahn06/pages/amps.html
and the subs AWES12P the eternal line
http://www.audiobahn.com/Audiobahn06/pages/woofers.html
swez on 07/22/2006 22:32:41
I take it you mean the A18001DT id the amp you are looking at? (1800 watts RMS @ 1 ohm)
"Hold on to your lug nuts... it's time for an overhaul" SMILE
Man, your trunk is gonna have more chrome in it than my old 1970 Pontiac Grandville. hehe (455 CID, 300 HP, Dual exhaust and 750 CFM Holley Carburator did)
Looked like these, but was a 2 door Hardtop:
http://www.classicpontiacs.com/seventies/b-bodies/1970/index.html
Swez
raulbustos on 07/24/2006 01:02:38
yeah that is the the amp but how would i know what the port is tuned at or should i just use my ears to determine where to set it at all im woried about is setting it to low and having the subs unload and the subs blow and since this isnt my stuff i like to take extra care in adjusting the amp see me personaly i allways use a sealed box so i never have to worry about port frequencys and i just set the ssf by whaere i like it and think it sounds good .
ps my verry first system that i had was stolen out of my car when i was in highschool this was the first thing that i ever had stolen from me the whole thing allmost made me give up car audio all together but that only lasted about two months after i got tired of listening to my engine for entertainment. it was an old (well brand new then) sony mobile ES set up and they took every thing my hu front and rear speakers four chanel amp mono amp and my two 10s and custom box and not to mention broke a $500 back window it was in a 88 camarro in all and all i think i lost about $3000 but it was defenatly a learning experience
swez on 07/24/2006 10:28:27
You might need to contact Audiobahn and ask them about the tuning frequency of that sub enclosure. My guess, it will be between 40-45 Hz. Confirm that OK?
You can do a good job of dialing in your SSF settings by ear and just watching the cones as you tweak. You know you are at the right SSF settings when the bass is clean and strong and plenty of air coming out of the port, but sub cones are behaving well.
FYI: When we get near the port tuning frequency, most bass energy comes out of the port and the sub cones don't move as much. If we go below port frequencies, the sub comes unload, become somewhat erratic and very little bass comes out of the port/vent.
That is hard on subs as the motor system becomes over-loaded and cannot adequately control the motion of the cones.
Swez
raulbustos on 07/24/2006 14:21:26
ah well see he dint buy it from audiobahn he got them from that link that i posted off of ebay
also do you know of where i could get a test tone that would cover these frequences
swez on 07/24/2006 19:53:40
Try NCH tone generator software off the Internet. This is a free service and has some decent tools for the serious audio enthusiast. Just browse the files and set up test tones you like for use with Windows Media Player.
Bass tones: 30, 40,60,80 & 100 Hz.
Midbass: 150,250 & 400 Hz.
Midrange: 500, 750, 1,000, 2000 Hz.
Highs: 2,500, 4,000, 8,000, 12,000, 16,000 & 20,000 Hz
Pink Noise is very useful for balancing and dialing in all audible frequencies. It is basically all frequencies blended into a full range signal that sounds like an FM station that has very low signal or off frequency.
http://www.world-voices.com/software/nchtone.html
This requires purchasing a license to get the full features available. Free to try, use it often, than buy.
This one is more complex but very interesting features:
http://www.softplatz.com/Soft/Education/Science/15120.exe
Swez
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