DBX 120

[clintrubber]

[quote author="mediatechnology"]Peter - It does look photoshop'd doesn't it? But hey FBG you make the rockin' world go 'round.[/quote]
Phew, let's be glad for them :wink: I saw they were drinking the non-lite coke though, so it might have been for real

 

[barclaycon]

Stephen. Thanks very much for the Aphex circuits.
However, I don't think that is the Big Bottom circuit as such. I think that's the LF section of the bandsplit. (I must admit I haven't examined it closely).
What would be great is to have a look at the Aphex 204 - a somewhat simpler implementation of this effect.
I know these schematics are hard to get hold of - but this is the best place if any - right ?

 

[SSLtech]

Completely photoshopped btw... Look at the legs and the lack of shadow "aura", then look at the fattened bits, adn see how they have their own fake "shadow".

Then look at the back of the legs and see how they lose 'focus' when they widen up the back of the thigh...

BTW, I've used the Big Bottom Aphex, and it's not a patch on the 120 operationally. All three which we have are the same 120A (I think, -I can check on Monday). The Big Bottom was a GREAT marketing name, but it's something dynamic with the low end, -or appears to be from using it- and not an 'extender'.

If DJs are using it and liking it, they'd be bowled over by the dbx... it's a MONSTER by comparison.

Keith

 

[CJ]

my butts cool

 

[CJ]

anybody done yet?
:twisted:

 

[CJ]

Maybe they ain't gonna recognize me now. :grin:

 

[wiz1der]

I had a dream last night.

I had 4 dbx 120's in my 900 rack! I had them labeled as "9120"

:wink:

















Then i woke up....
:sad:

 

[clintrubber]

The Ashdown bass amps came to mind, these have sub harmonic controls as well. I once used one in a shop to test some gear, IIRIC it didn't sound FX-ish (like the usual octave-down pedals like the Boss OC-2); it indeed made the sound a bit thicker, as advertised.

Soooo.... any familiar with how they do it ? Haven't been able to locate an Ashdown-schematic yet.

 

[SSLtech]

Importantly -I feel- the point should be made about how I (and everyone else I know) uses it.

We use it as an aux-send/aux-return device, so many parts of the circuit are unused or bypassed when we use it.

For motion picture mixing, the "super-sub-LF" output has to be directed to the LFE channel (the "point-one" channel of 5.1) and the rest of the full-range signal has to go to its originally-intended destination...

For example: A runaway exploding truck careening across the screen: you want the rest of the truck FX to pan right-to-left (or whatever) while the sub-harmonic FX remain resolutely tied to the LFE (Low Frequency Effects) channel. In addition, we have about 1½ million dollars worth of mixing console here, about 300 channels of 8-band, fully-parametric, all-singing, all-dancing EQ's here, and we've got things EQ'd just how we want them, thank you very much. -We DON'T want or need the LF EQ boost which ic applied to the direct component, thank you very much!!!

Now, DJ's who use this as an insert (not as an aux send/return) want stereo, they may well appreciate a bit more LF EQ option to play with, and they need the re-combining summing circuitry...

Personally, I'd LOVE and ADORE a stripped-down, "use-it-on-an-aux-send" version, with one input, one output, NO EQ, no summing; just the pre-filters, the fancy clipper and the post-filters.

That's all we use after all. The rest is wasted and unnecessary.

ours are all 120A's by the way, and -one thing which I forgot to mention- The metering goes faulty over time: After a year or two, the metering LEDs all show 'activity' even though there's nothing actually happening. -It's a gradual thing, but it looks like there may be some DC drift or something... I've never looked into it.

Keith

 

[SSLtech]

Dunno...

I have a few 900 racks here, so I can provide whatever mechanical info is of use to anyone...

Keith

 

[clintrubber]

Thanks Keith for the added info about use & the model-no.
Can very well imagine the exact application and details-of-use make this either a winner or a so-so box for a certain application.
My use would be for some little bit more oomph for my bass-rig (8*10")and while having/making one anyway I'd try it for mixing (music) as well, where it could be used in the send/return-fashion you described.

[quote author="mediatechnology"]OK then. That would easily fit on a 900 series form-factor.[/quote]
For a quick & dirty first version to see if it works, maybe putting the guts of a EU30 Beh. UO100 FX on a 900-sized carrier board could already do the trick? Not unlikely it'll give the detector- & polarity-swapper-sections already and for a stripped down aux-send/return version then only a little bit of pre- & post-filtering changes/additions needed...

... but it's not unlikely that starting from scratch had been the best way to do it :wink:

 

[SSLtech]

Peter,

I suspect that the Behringer version may be a PLL/tracking osc. sort of model, though it's hard to know for sure. Generally, they don't do well when 'chasing' non-tone-like program, or mixed-tones. The dbx or Rolls version works MASSIVELY better than the PLL approach, which produces unpleasant, atonal "hunting" notes when there's no single clear note to follow.

As a test, play an A and an E above it into the Behringer. If it can follow both individually but not together, then it's useless in the dbx application.

Keith

 

[CJ]

Don't let berringer run your company.
And wear sunscreen.
OK?

Who wants a pre stretched hood rat?
:shock:

 

[clintrubber]

[quote author="SSLtech"]Peter,

I suspect that the Behringer version may be a PLL/tracking osc. sort of model, though it's hard to know for sure. Generally, they don't do well when 'chasing' non-tone-like program, or mixed-tones. The dbx or Rolls version works MASSIVELY better than the PLL approach, which produces unpleasant, atonal "hunting" notes when there's no single clear note to follow.[/quote]
I'd be surprised if they had not simply copied the 'usual' method that octave-down boxes use (Boss OC-2, Pearl OC-7, non-deluxe EHX Octave Multiplexer etc), especially since they were plasticloning(TM) the BOSS & EHX pedal-ranges anyway.
But who knows they threw in a PLL for grins.

Without having really looked at it in enough detail I guess that the difference in the end-result of the dbx vs FX-boxes is in the filtering-details, since the rectifier & divider & polarity-swappers seem fairly identical. And in addition to that (and likely the more important one) the closer, 'in parallel' bands of the dbX120-something vs the divide by 2 and then once again by 2 of the FX-stompers.

As a test, play an A and an E above it into the Behringer. If it can follow both individually but not together, then it's useless in the dbx application.

I think I see where you're going, it's targeting the spaced bands by a ratio of 1.5, correct ?
The FX-stompers will err here I think, for the reasons above. In that sense (/for this test) the dbx is capable of duophonic action, while the stompers are not.

Regards,

Peter

 

[SSLtech]

Well, I'm guessing; it's not that I actually know...

But I can post an example soundfile of any given test through the dbx, if that helps... and my old Boss octave pedal would try and produce a single 'note', which would wander and be very annoying.

Keith

 

[clintrubber]

[quote author="SSLtech"]Well, I'm guessing; it's not that I actually know...

But I can post an example soundfile of any given test through the dbx, if that helps... and my old Boss octave pedal would try and produce a single 'note', which would wander and be very annoying.

Keith[/quote]
I guess it's all clear (sez me - someone who has had hands on just the BOSS OC-2 so far :wink: ), the dbx-method keeps things OK, while the FX-stompers could or will err when two notes are presented. The FX-boxes will err for such a test I assume, whatever method they're using, pol-swapper & 4013-FFs or a PLL.

For an FX it can be part of the charm, but obviously not so for the application where the dbx is used.

But I can post an example soundfile of any given test through the dbx

That'd be cool :thumb: What do you suggest, you come up with a suited example ? Or want me to supply something ?

No OC-2 here, all I have right now over here is the sub-gen that's onboard of this monster (not my pics & unit):
http://www.flickr.com/photos/matrixsynth/sets/72157600029611162/

Regards,

Peter

 

[SSLtech]

Well perhaps we should come up with some stuff first to use as 'standardized' tests for both...

I have a Bass guitar at home, I can record a low-E, then an E at 2nd Fret on the D-string, then an open A, then an A at second fret of the G-string... then combinations. There should be maybe a couple of different dynamic things, then we should play that "music" test through both the OC-2 and the 120A. Maybe the Boss will win for music "note" applications, but I've never tried the 120A for that in any scrutinised application, so who knows what the sonic differences will be?

then maybe we should try some complex inter-modulated stuff, like a whole 10-second music clip, and some definitely NON-musical stuff such as a movie explosion FX, or an ominous door-slam, a rocket-launch etc... I would expect the 120A to be king of the hill at this, but -if I'm surprised by a useful result from the Boss- you can bet I'm ready to run off and buy a Behringer faster than you know! :wink:

We should prepare a shortlist of a few short soundclips which each device excels at, and also a couple which each device struggles with... then we could compare and contrast.

Keith

 

[clintrubber]

[quote author="SSLtech"]Well perhaps we should come up with some stuff first to use as 'standardized' tests for both...
...
We should prepare a shortlist of a few short soundclips which each device excels at, and also a couple which each device struggles with... then we could compare and contrast.

Keith[/quote]
That'd be great :thumb:
And please tell if you don't see it happen there, can supply those bass-notes as well. Don't have any explosions handy though.
That doorslam might better be done at your side as well, I figure US-cars have better slamming-sounds to begin with.

Maybe we should make this 'scientific' but at the same time not too elaborate to be able to get it actually done.

Regards,

Peter

PS/FWIW, I feel those original octave-notes on bass might better be played 'one string thicker, 5 frets higher'... but it'd make it easier though for the elctronics, maybe we actually don't want that.

 

[CJ]

err, what is the status on the keef super-modified ssl redone side chain filter mod thingamajob, is that every thing it's cracked up to be?

all those compressors, just move the mic back a foot and throw them all in the dumpster.
that way i can scrounge the tubes.

 

[bcarso]

Putting on a DSP hat for a change, it would seem intuitively that the best way to go would be to do a running autocorrelation function on the input signal to determine the real period and hence the fundamental. Then you could go about your polarity flipping operation or whatever. This would accomodate instruments with almost no fundamental present, although I'm not sure how good adding a bottom octave to a sitar would sound :razz: