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SSL L500

Production Gear SSL All Pass Filters

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#1 GPBear


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Posted Today, 08:22 PM

The newest SSL mixing board, the L500


Not that I imagine anyone here's buying mixing boards, but I think it's important to note what the newest features of the newest boards of one of the larger and more respected audio companies are so that we can see what sound will most likely sound like in the near future.


What I got from that video, is the SSL L500 is the ONLY mixing board in the world (so far...) with an All Pass Filter. I think this means that the future of sound will use all pass filters. So, what is an All Pass Filter? As the video states, "It's a bit complicated".

"Phase" is the extra sound on top of the instrument in the mixer's headphones that's created by the difference in distance between the instrument's input and output mic. The sine waves of sound leaving the instrument reach the two mics at different times. Thus overlapping each other, dangerous if the crest of the wave entering the input mic match the trough of the wave when it enters the output, creating total destructive interference.


All Pass Filters basically allow you to remove phasing details and/or reverse polarity of specific frequencies. If you like the sonic detail you get from the difference in distance between your kick drum input mic and output mic heard, you don't do anything. All pass filters allow you to reduce the phase differences and/or reverse the polarity at specific frequencies. Reversing the polarity means changing the artifact itself, as if the output mic was the input mic and the input mic was the output mic (360), or (I guess) if they're equally mixed (180). You can reverse polarity of a specific frequency 3 different ways (NoChange-180-360) to get 3 different sounding different phases and then control how much of the phase is going to be heard.



Producer "We (Label heads) want this pop track to be as clean as possible,"
Audio engineer on the board "The phase (sonic artifact) of the snare drum is coming in around 2000hz, I'll use the all-pass filter around 2000hz and lower it to 0% to clean it up".


This "extra spice", I believe, is going to be the defining sonic feature of music for the coming decade, going on top of all the compressors we already had. In other words, the leg up studios will have over bedroom producers. "The feeling" of 2015 - Next New Board.

#2 GPBear


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Posted Today, 08:44 PM

You can't take away from the pure instrument's sound with the APF, only add levels of phasing on top of it.


I have the kick drum, "Bam".

I add the APF on the polarity setting: NoChange. This makes the kick drum now sound "Boom".

I can now control the amount of phasing on a spectrum that starts with the "APF 100%" to "APF OFF".


100% - 0%, "Boom" - "Bam" and the seemingly infinite combinations inbetween. This is going to allow (crazy) engineers to do crazy shit, the way I see it.


If you bring down phasing levels to "OFF" on any of the 3 polarities, it will all sound the same - The Instrument Itself "Bam". So, you get new spectrums (who fucking knows...) for each instrument in your mix


Boom - Bam

Thud - Bam

Oomph - Bam


One last thing, the SSL L500 has a touch screen, I don't know if it's the first in the world for mix boards. But, this allows you to physically draw what you want to hear, saving time on twisting knobs to get specific EQ bumps. Adding speed, probably reducing musicality. But it's interesting to note how synesthetic that is, drawing sounds.

Also tagged with one or more of these keywords: Production, Gear, SSL, All Pass Filters

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