# BFD 2 channel Use confusion



## N/A436 (Mar 10, 2010)

I have my BFD setup and EQing my sub perfectly from the left channel (thanks to this board and the great manuals and how to's :clap. Now I want to take advantage of the second channel. I want to use it to cutoff anything above 50HZ and then send that signal over to another power amp which controls my tactile tranducers (bass shakers). I read the coupling part, I'm one of the ones who falls in the : "*This has been confusing for some who use two subs and want to create different filters for each sub*"

_Here is the section on coupling: 

*Use the ENGINE L key to select the left audio channel. 

*Use the ENGINE R key to select the right audio channel. If you wish to process the left and right audio channels simultaneously (COUPLE mode), press both ENGINE keys together. In couple mode both engine LEDs light up. Whenever you edit one of the two audio channels and then switch to couple mode, the parameters of the active channel will be copied to the other; i.e. if you press ENGINE L before ENGINE R, left will be copied to right. _

My question is when I load my filters in REW (see below) I would put them in as CHANNEL 2? Then run my Output 2 into my poweramp right? 
50hz -48
60hz -48
70hz -48
80hz -48 etc etc


Also, can I use the operating level switch to increase the INPUT in channel 2? Is that the point of the switch. Example my Sub LVL on my Receiver would be say set to -1.0..can I boost that when coming into the BFD for channel two by using the OPERATING LEVEL SWITCH at +4db?


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## lsiberian (Mar 24, 2009)

GAWD said:


> I have my BFD setup and EQing my sub perfectly from the left channel (thanks to this board and the great manuals and how to's :clap. Now I want to take advantage of the second channel. I want to use it to cutoff anything above 50HZ and then send that signal over to another power amp which controls my tactile tranducers (bass shakers). I read the coupling part, I'm one of the ones who falls in the : "*This has been confusing for some who use two subs and want to create different filters for each sub*"
> 
> _Here is the section on coupling:
> 
> ...


You'd need a low-pass filter for what you are proposing. But you would put that filter on channel 2.

The CX2310 offers a crossover you could use for this setup if you want to give that a go.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Greg is right – the BGD has bandpass filters, not high or low pass. However, you might be able to “fake it” by applying enough deep-cutting filters above 50 Hz, especially since you’re talking about bass shakers which I presume have limited range to begin with. Use REW’s Target Curve set at 50 Hz and try to mimic the curve as best as you can for a quasi-24 dB cut off. Just keep in mind that since you won’t be getting a true high pass, your cut-off is pretty much “done” at 100 Hz – i.e., one octave above 50 Hz. A real low pass would be down 48 dB at 200 Hz, but you won’t be getting that. An outboard electronic crossover is your best bet.




> My question is when I load my filters in REW (see below) I would put them in as CHANNEL 2? Then run my Output 2 into my poweramp right?


Right.




> Also, can I use the operating level switch to increase the INPUT in channel 2? Is that the point of the switch. Example my Sub LVL on my Receiver would be say set to -1.0..can I boost that when coming into the BFD for channel two by using the OPERATING LEVEL SWITCH at +4db?


No, the BFD does not have independent input level controls. In fact, it has no input level controls at all. The rear panel switch merely changes the internal operating range. With the -10 dBV position, you have a quieter noise floor, but limited headroom. The +4 position shifts the operating range upwards, trading a noisier noise floor (forgive the poor terminology) for additional headroom.

Regards,
Wayne


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## N/A436 (Mar 10, 2010)

Thanks for the info guys. The shakers only have a freq response of 20hz - 80hz so with 12 filters available I can pretty much kill anything over 50-60.


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