Does anyone use a sub-sonic filter on their line-in source?

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Cpl-Chronic

Cpl-Chronic

Member (SA)
Heyya, :-D

I was wondering if anyone tried these?:

http://www.ebay.ca/itm/1-Mono-F-Mod-FMO ... 43a849ab42

It's a 50Hz High-Pass filter that runs before the amp.& dumps the bottom octaves below 50Hz & passes the rest(50-2000Hz) to your line-in. It's the same idea as the 20Hz rumble filters you put on phono-inputs to eliminate motor rumble, etc. from the input signal. It's gotta be some sort of passive filter designed for low voltage operation & it advertises a 10v maximum. If I can roll off the bottom 2 octaves(50-12.5Hz) & keep 50Hz & up with 40Hz @ -4 or -6db aprox., due to the 12db/oct slope, I can increase my headroom by cutting the really low bass tracks & still have that 'loudness' feel to the bass response. A blaster should have plenty of low/mid bass & sound warm & fuzzy. We can forget sometimes that a blaster really is a different sound than a home or car stereo & should have a punchy chest thumping type of bass, not groundshaking thunder or window rattling cannonfire. The woofers I shoe-horned into my GF are doing their jobs & 80's electro with it's pounding 808's can rock to the ceiling but some strong bass notes sometimes get too muddy from the cavernous harmonics reaching below the 50Hz mark. The amp is pushing all cones pretty well but you can hear it clip early on really low bass tracks that have alot of 20-40Hz bass energy.

Anyone have any experience or ideas about using this filter maybe?
 
Cpl-Chronic

Cpl-Chronic

Member (SA)
The line level filters arrived for my line-in inputs & they work by rolling off the LINE IN signal below 50Hz @ 12db/oct. This cuts out the sub-sonic range & prevents the AMPS from wasting TONS of power in that 20-50Hz range. It's the same idea as rumble filters on your PHONO input to weed out turntable rumble, disc wow, etc. It should give me more headroom & add to my SPL output down to the 50Hz mark. This is perfect for the 'LOUDNESS' effect that made the boomers so great, back then & now. The video is crap but you can hear the bass line & the shaking of the cabinet & book shelf.... Bass, Treble & volume are ALL @ about the 3:00 position & 'Super-Woofer' controls @ 0db(FLAT or CENTER position). You have to watch the entire video in full screen to get a good look at the controls & woofer travel, etc.


Shelf rattling DUB

Below is a list of MODS that were done to the Triple-7 ZEEE. Note that the guts & amplifiers are completely stock, including the line-in & preamp stages. Only the speaker components & 2-way crossovers have been replaced while the cabinet was dampened with deadmat & insualted to iliminate reflections.

List of MOD details:

Speakers upgraded

box dampened & insulated
2Khz/2-way/4-ohm crossovers added for outer 2-way system
the transformer moved to accomodate larger driver magnets/assemblies
F-MOD filters applied to the line-in for a 50Hz high-pass signal

Well, after trying different combinations of woofers the best sounding combination is as follows:

The outer woofers are part of a center channel kit which have 2 @ 6.5" woofers,
The frequency response is qutie good & flat up to 4Khz & the free-air resonant freq. or FS point is 63Hz. Perfect for upper bass punchy-ness & can be found here:
http://www.ebay.ca/itm/360429029111?ssP ... 1423.l2649

The black sub-woofers I used for the 'Super-woofer'(s) have a optimal sealed enclosure of just 0.16 cu. feet & a resonant freq. or FS point @ 38Hz Perfect for the bottom octaves so many boom-boxes lack. They can be purchased here:
http://www.ebay.ca/itm/290734609719?ssP ... 1423.l2649


Both sets of woofers are 4-ohm each so you can match impedances between old & new drivers & the unit still functions well. If you update your GF, I STRONGLY suggest using this combination of woofers to get a more flat BASS response down to 35Hz. The outside woofers are from a center channel kit & have a stiffer cone allowing it to give lots of punchy tight bass & remain flat up to about 4KHz. They do a great job of blending in between the sub drivers & the horn tweeters.
 
Fatdog

Fatdog

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Staff member
Just out of curiosity, are the tweeters pushing out 4 kHz and higher or is there a frequency gap in that setup? :huh:
 
Cpl-Chronic

Cpl-Chronic

Member (SA)
Fatdog said:
Just out of curiosity, are the tweeters pushing out 4 kHz and higher or is there a frequency gap in that setup? :huh:
Click to expand...

Nah, the x-overs cross at 2Khz/12db-oct & the drivers work good with that. Nice & balanced with no holes & strong all the way up into the highs. :breakdance:

I really lucked out that the project came together so well. I wish I could find some really smooth 1/2" dome tweeters to better fit the horns but they're impossible to find @ 4-ohms. As it is right now, the sound carries well & off axis response is also quite good. It's not perfect but it fills a room with good bass & pretty loud treble too. :-D
 
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