Subsonic filter for my sub?

  • Thread starter cameron paterson
  • Start date
C

cameron paterson

Audioholic Chief
I have an XLS 2502 Crown amp pushing my sub. Its tuned at 20hz. Would like a subsonic filter with the extra power of the amp. A cheap subsonic filter but not the little harrison plugs that go with the rca.
 
everettT

everettT

Audioholic Spartan
the crown has a high pass filter in the eq settings fwiw.
 
C

cameron paterson

Audioholic Chief
anything cheaper than the minidsp stuff?
 
KEW

KEW

Audioholic Overlord
I have an XLS 2502 Crown amp pushing my sub. Its tuned at 20hz. Would like a subsonic filter with the extra power of the amp. A cheap subsonic filter but not the little harrison plugs that go with the rca.
You didn't define cheap, but here is a $180 solution:
http://www.kabusa.com/frameset.htm?/accesss.htm

Crap, their website will not allow me to link to a specific product!
Use the link above and scroll down to the bottom of the items being sold (with prices listed).
Look at "KAB Great Sound Escorts (Active)" and find RF-1 (Rumble filter)

SPECIFICATIONS

  • -3dB @ 20 Hz 18dB/Oct
  • Unique Active Vertical Cancellation below 140 Hz
  • Dual Voltage Regulation
  • Output 5 Vrms
  • THD <0.05%
  • Noise -95dB
  • Dimensions 4.5" x 3" x 1.25"
  • Shipping Weight 4 Lbs
  • Power: 24VDC,0.75A Meanwell GE18I24-P1J
But before you spend money, there is some relevant information on the product page:
But the main source is feedback exciting the natural stylus/arm resonance between 7 and 12 hz. This produces a slow easily visible in and out motion of your woofers. If you cannot see this motion, the RF-1 will not solve your feedback problem. If you can see this motion, the RF-1 will solve your feedback problem.
And with rumble eliminated, the soundstage becomes more "still" and the bass actually tightens up because the woofers are no longer modulating and the power amp is no longer wasting current resources on sub audible noise.
If you driver is not moving around without producing sound, I'm not sure you have a problem! Setting a lit candle in front of the speaker is a good way to detect driver motion from the LP.

I do not know this product, but it seems to be a competent solution. I'd imagine there are several choices in the rumble filter category, and generally, they should offer exactly what I think you want: aggressive roll-off of subsonic frequencies (added to the 6dB/octave you already have)!
 
C

cameron paterson

Audioholic Chief
I sold the Dayton plate amp and now have the XLS Crown.
 
Alex2507

Alex2507

Audioholic Slumlord
It looks like there is a fixed 6dB/octave HP filter at 20Hz hard wired into the Crown Drivecore pro amps:
http://techtalk.parts-express.com/forum/tech-talk-forum/1325083-crown-xls-1502-subsonic-filter-confirmed

6dB/octave is not very aggressive and I could see that room gain might offset it, if room gain exists at subsonic frequencies, but at least the signal being sent to drive the subwoofer has reduced power for the lower frequencies.
You probably mean infrasonic ... and why wouldn't room gain exist? ... and why doesn't it exist at higher frequencies? Where's the cut off and why is there a cut off?
 
KEW

KEW

Audioholic Overlord
You probably mean infrasonic ... and why wouldn't room gain exist? ... and why doesn't it exist at higher frequencies? Where's the cut off and why is there a cut off?
Subsonic?, infrasonic?. My Sansui integrated had a "subsonic filter" which was labeled 14Hz, so I am used to calling it subsonic (and the OP called it a subsonic filter in the title):p. I remember watching my woofers move in and out (large excursions) without making a sound. When I flipped the switch I could rarely see them move much at all.
Room gain probably does exist at the lower frequencies, but you wouldn't hear it; but I don't know that for certain, so I said "if it exists"
Data-Bass has some good info! Here is a plot of room gain for a specific scenario:

And here is link to rest of article!
https://data-bass.com/data?page=content&id=80
 
Alex2507

Alex2507

Audioholic Slumlord
Subsonic?, infrasonic?. My Sansui integrated had a "subsonic filter" which was labeled 14Hz, so I am used to calling it subsonic (and the OP called it a subsonic filter in the title):p. I remember watching my woofers move in and out (large excursions) without making a sound. When I flipped the switch I could rarely see them move much at all.
Room gain probably does exist at the lower frequencies, but you wouldn't hear it; but I don't know that for certain, so I said "if it exists"
Data-Bass has some good info! Here is a plot of room gain for a specific scenario:

And here is link to rest of article!
https://data-bass.com/data?page=content&id=80
Kinda cool the way room gain works for <12Hz. It's also cool how sub 2 fixes sub 1 but sub 3 effs 'em both only to be further remedied by sub 4. You know what that means. I need 2 more subs.
 
TheWarrior

TheWarrior

Audioholic Ninja
and why doesn't it exist at higher frequencies? Where's the cut off and why is there a cut off?
Wavelength! The Transition Frequency changes room to room, but it is the point at which bass stops being omni directional and gains forward bias as frequency increases.

20 hz = 56.5 feet in diameter
80 hz = 14.1 feet in diameter
120 hz = 9.4 feet in diameter
20 khz = 0.56 inches in diameter

When you have giant sound waves interacting with an enclosed space, it mostly induces room modes and standing waves between parallel boundaries, some call that 'Room Gain' (Resonance was used in the article).

But as frequency increases, the wavelength gets smaller at which point 'Room Gain' is really more an issue of 'Room Treatment' and how many reflective surfaces you have.

None of which is really the rooms fault, just naturally occurring phenomena that has to be dealt with in any sound reproducing system!
 
lovinthehd

lovinthehd

Audioholic Jedi
Wavelength! The Transition Frequency changes room to room, but it is the point at which bass stops being omni directional and gains forward bias as frequency increases.

20 hz = 56.5 feet in diameter
80 hz = 14.1 feet in diameter
120 hz = 9.4 feet in diameter
20 khz = 0.56 inches in diameter

When you have giant sound waves interacting with an enclosed space, it mostly induces room modes and standing waves between parallel boundaries, some call that 'Room Gain' (Resonance was used in the article).

But as frequency increases, the wavelength gets smaller at which point 'Room Gain' is really more an issue of 'Room Treatment' and how many reflective surfaces you have.

None of which is really the rooms fault, just naturally occurring phenomena that has to be dealt with in any sound reproducing system!
Wavelengths expressed in diameter?

Article on the Schroeder frequency https://www.soundandvision.com/content/schroeder-frequency-show-and-tell-part-1
 

Latest posts

newsletter

  • RBHsound.com
  • BlueJeansCable.com
  • SVS Sound Subwoofers
  • Experience the Martin Logan Montis
Top