EQ as subsonic

[XHiFiX 10+ year member]

If you have a ported sub which calls for a subsonic filter, but your amp doesn't have one.. would it work to use the parametric EQ on the HU, choose a center freq at and below the tuning freq of the ported box, then reduce those bands to mimic a xover slope??

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[audioholic 5,000+ posts]

If you have a ported sub which calls for a subsonic filter, but your amp doesn't have one.. would it work to use the parametric EQ on the HU, choose a center freq at and below the tuning freq of the ported box, then reduce those bands to mimic a xover slope??

Is this a serious question, or one of those joke threads?

 

[Louisiana_CRX 5,000+ posts]

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[XHiFiX 10+ year member]

No it's serious. I get the idea that the SSF is there to cut out the freq's below the ports' tuning freq because below that point, the sub "doesn't see an enclosure" anymore and prone to unloading. Well with an EQ, can't you do the same "cutting" by bringing down the freqs in that range.

BASICALLY, I'm just looking for an alternative method if there is one, to compensate for the lack of a subsonic filter in the equipment.

 

[audioholic 5,000+ posts]

No it's serious. I get the idea that the SSF is there to cut out the freq's below the ports' tuning freq because below that point, the sub "doesn't see an enclosure" anymore and prone to unloading. Well with an EQ, can't you do the same "cutting" by bringing down the freqs in that range.
BASICALLY, I'm just looking for an alternative method if there is one, to compensate for the lack of a subsonic filter in the equipment.

So go get a piece of equipment that has a subsonic filter built in. Either a new h/u, or a decent EQ. The fact that none of your equipment has a SSF makes me wonder what kinda stuff you are running.
While your idea *might* work under just the right circumstances, sort of, there is a better chance it would only give a false sense of security... and its a hella ghetto idea anyway. You know you can buy simple EQ's with a built-in SSF for next to nothing these days right? Step into the 21'st century and get some decent processing. You seem to think your amp has an SSF, or you get none at all.

 

[Rich B 5,000+ posts]

Subsonic filters arent an EQ, they are a high pass crossover.

 

[audioholic 5,000+ posts]

Subsonic filters arent an EQ, they are a high pass crossover.

He understands that. You dont understand his idea, but that's okay, just be satisfied in knowing that I told you its a bad one.

 

[XHiFiX 10+ year member]

So go get a piece of equipment that has a subsonic filter built in. Either a new h/u, or a decent EQ. The fact that none of your equipment has a SSF makes me wonder what kinda stuff you are running.
While your idea *might* work under just the right circumstances, sort of, there is a better chance it would only give a false sense of security... and its a hella ghetto idea anyway. You know you can buy simple EQ's with a built-in SSF for next to nothing these days right? Step into the 21'st century and get some decent processing. You seem to think your amp has an SSF, or you get none at all.

Thanks for the advice.

Well I really like my amp and don't want to replace it. It's a Rockford Fosgate Power T3002, 923 Watts RMS @ 2 Ohms Bridged. It has Hi/Lo 12dB/Oct X-overs but the freq range is 40-400Hz, iirc. I need a SSF around 30Hz.

I guess I could just use a pair of those Harrison Labs fmods or adjustable xovers. instead of my ghetto idea. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[Rich B 5,000+ posts]

He understands that. You dont understand his idea, but that's okay, just be satisfied in knowing that I told you its a bad one.

I understood him just fine, but I wanted to be sure he understands an EQ is not a crossover.

 

[mrogowski 5,000+ posts]

It should work fine provided you understand that you will still have some output despite the lowest level you apply on your EQ. I'm surprised your power amp doesn't have one though.

 

[bass_lover1 10+ year member]

It should work fine provided you understand that you will still have some output despite the lowest level you apply on your EQ. I'm surprised your power amp doesn't have one though.

Even the SSF is going to allow frequencies below a set point to be played. A 12db SSF set at 30hz is still going to play 15hz, but 12db quieter.

If he can set the EQ to 15hz (don't know why anyone would set one to go that low) and he can minimalize it then it would sort of work, with a wide enough Q, but a true SSF is going to probably be more effective.

Audioholic,

My sub amp doesn't have a SSF either, should I ditch my 2.2HV for an amp that does? Since that seems to be your logic, to "step into the 21st century."

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[mrogowski 5,000+ posts]

It should actually be more effective *if* the frequency q can be adjusted to represent a very steep roll off.