Where To Set Subsonic Filter

DD Audio Tech Talk | WRITTEN Past AARON TRIMBLE | 02 MARCH 2017

What does the subsonic filter do exactly? A lot of folks would say it cuts out my depression bass, and they wouldn't exist wrong. What few of people actually realize, if an amplifier has a subsonic filter prepare at 50 Hz, everything beneath this is not expressionless and gone. In fact, it's safe to say when a filter is indeed set up to 50 Hz, a frequency similar 30 Hz is still quite audible, albeit quieter than it would be if the filter was not utilized at all.

This is not going to turn into an "everything beneath 40 Hz is wasted data" statement, nothing is wasted if one is listening to information technology. DD Tech Talk readers know we like the deep down nitty gritty beats as much as the next bass enthusiast, just nosotros're besides not agape of using our subsonic filter to optimize our systems. When talking nigh subsonic filters, readers may hear the term "slope" thrown around. This refers to the charge per unit at which music will be adulterate below the subsonic filter frequency. All DD 1000 Series and DM Series Monoblocks use 24dB/octave subsonic filters. This means a subsonic filter at l Hz would be 24 decibels downward in amplifier output at 25 Hz, subwoofer box and vehicle transfer office all the same. In all reality, the filter will probably never get set this loftier, merely it then begs the question… how high should the filter be set?

DD R&D solicited the aid of diverse people effectually the DD Headquarters to see at what point they could hear their music exist affected past a subsonic filter. For this experiment nosotros loaded up our trusty Isuzu Trooper with a 3510g ESP in a 1.5 cubic pes enclosure with xx square inches of port, tuned to 35 Hz (the vehicle plays a practiced bit lower than that), and powered it off an M2c (2400 watt amp). A complement of DD door speakers and a 60 watt per channel speaker amp were included to allow for a full range listening feel.

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Each listener saturday in the driver's seat and listened to music stored on their prison cell phones to insure that each person was familiar with their music. As they listened, a second person would turn the subsonic filter on the M2c upward until the listener signaled that they could hear the difference. Here are some of the tracks that they listened to.

Track	Position on Knob	SS Frequency
Set Me On Fire – Pendulum	3:00	42 Hz
Purple Lamborghini – Rick Ross & Skrillex	three:00	42 Hz
The Wretched – Nine Inch Nails	2:00	38 Hz
Right Where I Demand To Be – Gary Allen	1:xxx	36 Hz
Give Information technology All We Got This night – George Strait	one:30	36 Hz
Blood – In This Moment	3:30	44 Hz
Don't End Assertive – Journeying	12:30	32 Hz
Take A Little Ride – Jason Aldean	3:00	42 Hz
Nosotros Will Rise – Arch Enemy	iii:thirty	44 Hz
Skyhunter – Dethklok	3:00	42 Hz

There's pretty wide range of music that was played. Styles range from country music to Cartoon metal bands, all the style back to British drum and bass, and dubstep. Consistently, nigh listeners were incapable of discerning the difference betwixt a subsonic filter set at xx Hz and one prepare near 30 Hz. Near folks had a difficult time perceiving output losses below about 36 Hz.

For the mainstream listener, setting a subsonic filter effectually 35 Hz will let them to hear all their music content, missing nothing on any performance, while protecting their system. Our next articles will also show ways to optimize amp power and cone excursion for the listeners bandwidth.

Some of you might accept read that list and said, "Yes but I thought y'all guys liked bass, where is the low stuff?" Some of our listeners were big bass heads. They know who Decaf is and they curlicue to DJSNT, Rusticals, and all the rest on the daily. These listeners are a special brood. Bass music does not come up from an instrument with strings, brass horn or 808 samples. 25 Hz doesn't come from anything simply a pipe organ, and about of us take never been to a car audio competition and demo'd someone's ride while listening to a Wurlitzer Theatre Pipe Organ collection. Bass music is primarily digitally modified sine-waves being injected into other music, and it should be treated in it's own special way. Check out some of our listening testing with slowed and modified tracks.

Track	Position on Knob	SS Frequency
Delusional – Tech N9ne (DJSNT)	10:xxx	24 Hz
How You Do That – Master P ft Young Claret (29-42 Hz)	xi:thirty	28 Hz
Lil Ane – Dirty Sprite 2 (35 Hz)	11:00	26 Hz
Popular The Trunk – Yelawolf	eleven:thirty	28 Hz
My Hooptie – Sir Mix-A-Lot (27, 34, 41 Hz)	11:00	26 Hz

Here, users listening to slowed music noticed the subsonic filter kick in much sooner. Tracks with heavy doses of modified sine moving ridge frequencies will be affected earlier, much as it would if using the DD app frequency generator, as the corner frequency of the SS filter enters the peak of the sine wave frequency.

The purpose of this experiment was to encounter how high the filter could be ready before a listener became aware that their music'due south bass was being reduced. From here we can branch out and look at the electrical and mechanical side of the equation. How much subsonic filter is needed to proceed a woofer in control and how much is needed to maximize output while minimizing clipped betoken. Be certain to bank check in with the Tech Talk next time when we delve into the how the subsonic filter saves your amp, your sub and makes your organisation play louder.