Subsonic Frequency Filter - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 11 Old 01-04-2012, 08:00 AM - Thread Starter
Member
 
jsgrise's Avatar
 
Join Date: Jan 2006
Posts: 143
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
I run my VTF-15H with one port open and EQ2.

If the port is tuned to 16Hz, which frequency should I put my subsonic filter on with my SMS-1? What about when it is tuned to 22Hz? Is there a guideline that I should follow? Also, which slope do you recommend?

All this is mostly to avoid port chuffing when played loud.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


PSN: le_gros_thon
jsgrise is offline  
Sponsored Links
Advertisement
 
post #2 of 11 Old 01-04-2012, 08:19 AM
Senior Member
 
ironhead1230's Avatar
 
Join Date: Jan 2006
Location: Laurel, MD
Posts: 428
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 46
Quote:
Originally Posted by jsgrise View Post

I run my VTF-15H with one port open and EQ2.

If the port is tuned to 16Hz, which frequency should I put my subsonic filter on with my SMS-1? What about when it is tuned to 22Hz? Is there a guideline that I should follow? Also, which slope do you recommend?

All this is mostly to avoid port chuffing when played loud.

The sub already has a built in high pass that changes depending on the EQ mode. What material are you getting port chuffing? Have you tried running with both ports open? That will give you double the port area and should minimize any port chuffing.

-Mike
ironhead1230 is offline  
post #3 of 11 Old 01-04-2012, 08:44 AM - Thread Starter
Member
 
jsgrise's Avatar
 
Join Date: Jan 2006
Posts: 143
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
I get port chuffing on heavy bass material like Inception and Polar Express, such as the train scene at the beginning. I am getting the chuffing with 2 ports open.

Pete at HSU told me to run it one port plugged and EQ2 to minimize the port noise. He also told me that a subsonic filter could help but didn't tell me which frequency to use.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


PSN: le_gros_thon
jsgrise is offline  
post #4 of 11 Old 01-04-2012, 09:03 AM
AVS Special Member
 
NicksHitachi's Avatar
 
Join Date: Jul 2007
Location: Wilmington, NC
Posts: 3,636
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 99 Post(s)
Liked: 143
Quote:
Originally Posted by jsgrise View Post

I get port chuffing on heavy bass material like Inception and Polar Express, such as the train scene at the beginning. I am getting the chuffing with 2 ports open.

Pete at HSU told me to run it one port plugged and EQ2 to minimize the port noise. He also told me that a subsonic filter could help but didn't tell me which frequency to use.

IMO this solution was more about controlling driver excursion down low.

I would not add a subsonic filter to a commercial sub. Defeats the purpose of overpaying if you have to further engineer to overcome something as fundamental as port noise.

What Pete prbably didnt tell you was it wasnt port noise heard. Every sub has a limit and youve probably reached it.

The only subsonic filter you need is your right hand on the gain knob. Turn counter clockwise until bad sounds stop.
NicksHitachi is online now  
post #5 of 11 Old 01-04-2012, 09:42 AM - Thread Starter
Member
 
jsgrise's Avatar
 
Join Date: Jan 2006
Posts: 143
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Quote:
Originally Posted by NicksHitachi View Post

IMO this solution was more about controlling driver excursion down low.

I would not add a subsonic filter to a commercial sub. Defeats the purpose of overpaying if you have to further engineer to overcome something as fundamental as port noise.

What Pete prbably didnt tell you was it wasnt port noise heard. Every sub has a limit and youve probably reached it.

The only subsonic filter you need is your right hand on the gain knob. Turn counter clockwise until bad sounds stop.

That makes sense. It looks more like over excursion than port noise. But my volume knob is only at 10 o'clock and my receiver LFE level set at 0dB.

I tried different locations. Of course the corner would provide more oomph but it would make the response graph looks really bad...


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


PSN: le_gros_thon
jsgrise is offline  
post #6 of 11 Old 01-04-2012, 12:01 PM
AVS Special Member
 
JHAz's Avatar
 
Join Date: Mar 2009
Posts: 3,946
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 88 Post(s)
Liked: 154
Quote:
Originally Posted by jsgrise View Post

That makes sense. It looks more like over excursion than port noise. But my volume knob is only at 10 o'clock and my receiver LFE level set at 0dB.

I tried different locations. Of course the corner would provide more oomph but it would make the response graph looks really bad...

where your volume knob is set means virtually nothing about how close you are to max power. Depends on too many variables. Varies from sub to sub, might vary between 2 of the exact same model. If it's overdriving, it's overdriving, and you need to turn it down.
JHAz is online now  
post #7 of 11 Old 01-04-2012, 12:28 PM
AVS Special Member
 
Wrager's Avatar
 
Join Date: Sep 2002
Location: Acworth, GA
Posts: 1,283
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 12
Are you using the SMS-1 to boost the lower frequencies?
Wrager is offline  
post #8 of 11 Old 01-04-2012, 12:52 PM
AVS Special Member
 
NicksHitachi's Avatar
 
Join Date: Jul 2007
Location: Wilmington, NC
Posts: 3,636
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 99 Post(s)
Liked: 143
Quote:
Originally Posted by Wrager View Post

Are you using the SMS-1 to boost the lower frequencies?

I totally missed he was using an SMS-1. Set the high pass At the tuning frequency. If not the SMS may actually be boosting below tuning for a flat target which is the opposite of the built in highpass on the amp. You may be risking damage as theres no protection for your driver below tuning other than amp limiting and if you boost through that well, bad things happen.

How low does an SMS go?

You may be able to set the high pass a bit below tuning without problems but id start at the tuning frequency and see how it behaves.
NicksHitachi is online now  
post #9 of 11 Old 01-04-2012, 02:52 PM - Thread Starter
Member
 
jsgrise's Avatar
 
Join Date: Jan 2006
Posts: 143
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Quote:
Originally Posted by Wrager View Post

Are you using the SMS-1 to boost the lower frequencies?

No, I'm not using any boost at all at any frequency. I only cut through the peaks.

Quote:
Originally Posted by NicksHitachi View Post

I totally missed he was using an SMS-1. Set the high pass At the tuning frequency. If not the SMS may actually be boosting below tuning for a flat target which is the opposite of the built in highpass on the amp. You may be risking damage as theres no protection for your driver below tuning other than amp limiting and if you boost through that well, bad things happen.

How low does an SMS go?

You may be able to set the high pass a bit below tuning without problems but id start at the tuning frequency and see how it behaves.

I run the SMS-1 in manual mode and don't use any boost at all. I think it is more a driver excursion problem than anything else (unless someone has another hypotheses). I'll try to play around with some different HPFs and see if it improves anything.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


PSN: le_gros_thon
jsgrise is offline  
post #10 of 11 Old 01-04-2012, 04:24 PM
AVS Special Member
 
sputter1's Avatar
 
Join Date: Jan 2010
Location: Ontario
Posts: 1,372
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 41
Quote:
Originally Posted by jsgrise View Post

I run my VTF-15H with one port open and EQ2.

If the port is tuned to 16Hz, which frequency should I put my subsonic filter on with my SMS-1? What about when it is tuned to 22Hz? Is there a guideline that I should follow? Also, which slope do you recommend?

All this is mostly to avoid port chuffing when played loud.

I know that the HPF in the SMS-1 rolls off quicker than the HPF in the 15H for whatever reason. My subs rolloff at 13hz with SMS set at 10Hz, If I set the the SMS HPF at 15hz it drops long before 13hz.
I haven't checked this with REW however just via SMS-1. I set my SMS-1 t10hz and let the sub deal with the filtering.
sputter1 is offline  
post #11 of 11 Old 01-05-2012, 04:12 AM
AVS Special Member
 
NicksHitachi's Avatar
 
Join Date: Jul 2007
Location: Wilmington, NC
Posts: 3,636
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 99 Post(s)
Liked: 143
Quote:
Originally Posted by sputter1 View Post


I know that the HPF in the SMS-1 rolls off quicker than the HPF in the 15H for whatever reason. My subs rolloff at 13hz with SMS set at 10Hz, If I set the the SMS HPF at 15hz it drops long before 13hz.
I haven't checked this with REW however just via SMS-1. I set my SMS-1 t10hz and let the sub deal with the filtering.

This is pretty typical for a HP.
NicksHitachi is online now  
Reply Subwoofers, Bass, and Transducers

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off