I have the Rockford P6002 and there are two dials on it.One is the gain and the other says HZ at the bottom and goes from 40 to 400.Just wondering what the HZ one is for and what do I set it on.I am running a single 12 at 4 ohms bridged in a ported enclosure tuned to 45hz.Does anyone know where I can get a pair of 45hz fmods all I can find are 20,30,50,70hz?Also when I put the fmods on will I gain anything as far as db's or deeper bass or is it solely for protecting the sub from blowing at low frequencys?
Replies (6)
MrBrownstone on 09/21/2006 22:14:05
The Hz setting is the crossover. Depending upon whether or not you are using the crossover as High Pass or Low Pass (HP/LP), your crossover will cut frequencies below or above the setting you have selected.
ex: HP 80Hz, frequencies below 80Hz will diminish
ex: LP 80Hz, frequencies above 80Hz will diminish
Your goal is to set that crossover around 80Hz for your subwoofers, and select LP (low pass) meaning you want the lower frequencies to pass to your subs. The opposite is true for your other speakers.
swez on 09/22/2006 08:54:38
You can use the 50 Hz., HP F-Mods for sub-sonic filtering here.
The 50 Hz., version will net about -3dB attenuation at 45 Hz., and a
-12dB cut at 25.0 Hz. We can use the bass boost or EQ boost to compensate for that loss by using a +3dB boost at 40-45 Hz. This is a typical centering frequency for most amps that have a Bass Boost feature.
This F-Mod is solely to protect your woofer from "unloading" and going out of control in this ported enclosure. It will only "cut/attenuate" frequencies below 50 Hz. It is a passive filter and cannot boost or add dB's as it is passive.
swez
MrBrownstone on 09/22/2006 17:19:49
That, or you could just set the amplifier's High Pass @ 40Hz and have the same cutoff @ 20Hz...although the unloading wouldn't be stopped.
I would vent that enclosure @ 32-35Hz, and you won't have any issues with unloading. However you want to do it, there's nothing wrong with venting that enclosure very low with respect to sound quality, output, and since it's vented so low, there isn't much information below the port frequency even without the crossover being on.
If you haven't built the box, that may be a great way to go as well.
swez on 09/22/2006 17:49:30
Quote: "That, or you could just set the amplifier's High Pass @ 40Hz and have the same cutoff @ 20Hz...although the unloading wouldn't be stopped."
Indeed, you can set the amps HPF at ~45 Hz., and all you would need is a LPF in your HU, set between 80-100 Hz. This creates a Bandpass network, bracketed between 45 - 80/100 Hz. That is, assuming your HU has a sub filter feature. If not, a LPF F-Mod value of 70 or 100 Hz., would be suitable as well. Here are the stock F-Mods carried by Parts Express:
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=3
What HU make and Model # are you using now or plan to use in the future?
swez
anonymous_a on 09/23/2006 21:39:48
Here's my equipment Rockford P6002,Cadence 12" Triple X(new model) Pioneer Deh-3800(2006 Model) 2 Rockford 3-way 6x9s,and last but not least a Visonik 400 watt amp for 6x9s.The box is 3.5 cubic feet slot ported tuned to 45 Hz.See I would've got an amp with the ssf filter built right on but I got a great deal on the P6002 so I bought that and figured just get an fmod to stop the unloading and harmful frequencies. I came up with a few other questions while here so here I go.I plan on doing the big three but was just wondering what guage wire to use, I'm running 1/0 guage to a fused distro that spits out one four guage and one eight guage that run to the trunk.I am thinking about upgrading to a JBL 1201 or something along that line in time.So can I get away with the four guage big three for this amp and the future upgrade, also how do I figure out the fuse size for the positive wire that goes from alt. to batt.? This next one might be a little silly but how do you get the four guage power and ground wire into the terminals without bunching up on you? Here's the link http://www.rockfordfosgate.com/products/product_details.asp?cat_id=2&series_id=6&family_id=20&item_id=91285&locale=en_US Sorry for the long post guys thanks for your time!
swez on 09/24/2006 10:53:59
The length and content of your post is fine. However, w/o paragraph breaks for each main topic, makes for a difficult read and figuring out how to answer each item of dicussion. (Avoid run on sentences and break things up as shown in my reply OK?) TY
Interesting that that link shows general specs for the 6002 and says it has infrasonic filtering. However, looking at the manual, the manual does not show that feature available on this amp model... hummm!
That HU has a 12dB slope HPF and is selectable down to 50 Hz. You can set the HPF for the rear RCA channels at 50 Hz., and set your sub amp LPF between 80-100 Hz. Here, you now have a bandpass notch filter that does not require F-Mods. Just use a small amount (~+3dB)bass boost on the amp to kick up the 45 Hz., content lost to the 50 Hz., HPF in your HU. Just observe the sub cone at higher volumes to ensure it is not unloading on you. Test tones are most helpful here. (35, 40, 45 and 50 Hz., will tell if you've got it right)
Since the wiring for the "Big 3" upgrade is usually very short, (under 6 feet per line) you may be fine with #4 gage, fused at 100-150A's. If your amps and vehicle anticipated needs are higher than that, drop to #2 and use a 200A fuse.
"Wire bunching" is often reduced by twisting the fine wires tightly before installing them into the termination lugs. Some wire makers use high strand counts of very fine wire. These can be a PITA to install w/o frays sticking out and possible shorts to chassis ground of the amp.
Here, a pair of sharp sissors come in handy. Just snip off a "few" strands and twist the wires as tight as possible and try again. Repeat as needed until it fits tight and no frays are present. As long as the wire count remains above ~95% of original, you'll be OK. I usually pull the insulation jacket over the snipped ends so they are covered and don't pose shorting problems later. The insulation jacket should butt snugly to the terminal block with adequate exposed wire to seat well
into the termination block, but no bare wires are showing.
Hope that helps, COFFEE
swez
PS See how much easier this reply is to read than the format used in your earlier post. We really do appreciate readable posts and ask others to use similar formats with lots of complex and various details. It just works soooo much better for every body. SMILE
Replies (6)
MrBrownstone on 09/21/2006 22:14:05
The Hz setting is the crossover. Depending upon whether or not you are using the crossover as High Pass or Low Pass (HP/LP), your crossover will cut frequencies below or above the setting you have selected.
ex: HP 80Hz, frequencies below 80Hz will diminish
ex: LP 80Hz, frequencies above 80Hz will diminish
Your goal is to set that crossover around 80Hz for your subwoofers, and select LP (low pass) meaning you want the lower frequencies to pass to your subs. The opposite is true for your other speakers.
swez on 09/22/2006 08:54:38
You can use the 50 Hz., HP F-Mods for sub-sonic filtering here.
The 50 Hz., version will net about -3dB attenuation at 45 Hz., and a
-12dB cut at 25.0 Hz. We can use the bass boost or EQ boost to compensate for that loss by using a +3dB boost at 40-45 Hz. This is a typical centering frequency for most amps that have a Bass Boost feature.
This F-Mod is solely to protect your woofer from "unloading" and going out of control in this ported enclosure. It will only "cut/attenuate" frequencies below 50 Hz. It is a passive filter and cannot boost or add dB's as it is passive.
swez
MrBrownstone on 09/22/2006 17:19:49
That, or you could just set the amplifier's High Pass @ 40Hz and have the same cutoff @ 20Hz...although the unloading wouldn't be stopped.
I would vent that enclosure @ 32-35Hz, and you won't have any issues with unloading. However you want to do it, there's nothing wrong with venting that enclosure very low with respect to sound quality, output, and since it's vented so low, there isn't much information below the port frequency even without the crossover being on.
If you haven't built the box, that may be a great way to go as well.
swez on 09/22/2006 17:49:30
Quote: "That, or you could just set the amplifier's High Pass @ 40Hz and have the same cutoff @ 20Hz...although the unloading wouldn't be stopped."
Indeed, you can set the amps HPF at ~45 Hz., and all you would need is a LPF in your HU, set between 80-100 Hz. This creates a Bandpass network, bracketed between 45 - 80/100 Hz. That is, assuming your HU has a sub filter feature. If not, a LPF F-Mod value of 70 or 100 Hz., would be suitable as well. Here are the stock F-Mods carried by Parts Express:
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=3
What HU make and Model # are you using now or plan to use in the future?
swez
anonymous_a on 09/23/2006 21:39:48
Here's my equipment Rockford P6002,Cadence 12" Triple X(new model) Pioneer Deh-3800(2006 Model) 2 Rockford 3-way 6x9s,and last but not least a Visonik 400 watt amp for 6x9s.The box is 3.5 cubic feet slot ported tuned to 45 Hz.See I would've got an amp with the ssf filter built right on but I got a great deal on the P6002 so I bought that and figured just get an fmod to stop the unloading and harmful frequencies. I came up with a few other questions while here so here I go.I plan on doing the big three but was just wondering what guage wire to use, I'm running 1/0 guage to a fused distro that spits out one four guage and one eight guage that run to the trunk.I am thinking about upgrading to a JBL 1201 or something along that line in time.So can I get away with the four guage big three for this amp and the future upgrade, also how do I figure out the fuse size for the positive wire that goes from alt. to batt.? This next one might be a little silly but how do you get the four guage power and ground wire into the terminals without bunching up on you? Here's the link http://www.rockfordfosgate.com/products/product_details.asp?cat_id=2&series_id=6&family_id=20&item_id=91285&locale=en_US Sorry for the long post guys thanks for your time!
swez on 09/24/2006 10:53:59
The length and content of your post is fine. However, w/o paragraph breaks for each main topic, makes for a difficult read and figuring out how to answer each item of dicussion. (Avoid run on sentences and break things up as shown in my reply OK?) TY
Interesting that that link shows general specs for the 6002 and says it has infrasonic filtering. However, looking at the manual, the manual does not show that feature available on this amp model... hummm!
That HU has a 12dB slope HPF and is selectable down to 50 Hz. You can set the HPF for the rear RCA channels at 50 Hz., and set your sub amp LPF between 80-100 Hz. Here, you now have a bandpass notch filter that does not require F-Mods. Just use a small amount (~+3dB)bass boost on the amp to kick up the 45 Hz., content lost to the 50 Hz., HPF in your HU. Just observe the sub cone at higher volumes to ensure it is not unloading on you. Test tones are most helpful here. (35, 40, 45 and 50 Hz., will tell if you've got it right)
Since the wiring for the "Big 3" upgrade is usually very short, (under 6 feet per line) you may be fine with #4 gage, fused at 100-150A's. If your amps and vehicle anticipated needs are higher than that, drop to #2 and use a 200A fuse.
"Wire bunching" is often reduced by twisting the fine wires tightly before installing them into the termination lugs. Some wire makers use high strand counts of very fine wire. These can be a PITA to install w/o frays sticking out and possible shorts to chassis ground of the amp.
Here, a pair of sharp sissors come in handy. Just snip off a "few" strands and twist the wires as tight as possible and try again. Repeat as needed until it fits tight and no frays are present. As long as the wire count remains above ~95% of original, you'll be OK. I usually pull the insulation jacket over the snipped ends so they are covered and don't pose shorting problems later. The insulation jacket should butt snugly to the terminal block with adequate exposed wire to seat well
into the termination block, but no bare wires are showing.
Hope that helps, COFFEE
swez
PS See how much easier this reply is to read than the format used in your earlier post. We really do appreciate readable posts and ask others to use similar formats with lots of complex and various details. It just works soooo much better for every body. SMILE
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