# BFD in the studio



## Guest (Nov 27, 2006)

Hi all.

Do you guys have any thoughts about what the FBD does when it's in neutral?

I currently use one band of one (set up as a parametric) to tame a reasonant peak I have in my control room. 

Having done an a/b comparison i feel that even in bypass the ADC and DAC are effecting the signal reaching my genelecs. Has anyone done an analysis? Without some major de-rigging I can't test at the mo...


Matthew


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## brucek (Apr 11, 2006)

> Do you guys have any thoughts about what the FBD does when it's in neutral?


I believe the ADC/DAC is always engaged. The IN/OUT button can disengage the parametric filters only (when the green led is off) or it can disengage the parametric filters *and* the feedback filters (when the green led is flashing).

The only true bypass without digitizing the signal would be to pull out the jacks and short them together.

brucek


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## Guest (Nov 27, 2006)

Hi Brucek. Thanks for your reply. I guessed as much 

Any comments about sound quality as compared to hard bypassing the unit?

Matthew


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## brucek (Apr 11, 2006)

> Any comments about sound quality as compared to hard bypassing the unit?


Night and day. This a $120 device, so in its defense I am impressed with what it accomplishes. But to use it in a Hi-Fi or recording capacity when applied to full range signal, I would not recommend it. For subwoofer equalization it is great.

The noise floor spec is 94dB and has been measured at about 90dB by one of the members here. That's not even 15 bits of dynamic range. You will hear that noise floor in a full range signal. The distortion in a BFD is quite acceptable, but the noise is not. It also has a rather poor crosstalk figure of -76dB. You would want a device with a better figure than that for a studio.

brucek


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## Guest (Nov 27, 2006)

Many thanks for your reply.

Yes not the most impressive spec. Reminds me of my time many moons ago with my RD8. The crosstalk wasn't that bad though

Poor thing - maybe I'll have to retire it!


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## brucek (Apr 11, 2006)

Better specs are listed for the FBQ2496, which is only marginally more expensive at about $180.

It boasts a dynamic range of 107dB, which if true would be over 17 bits of resolution and the resultant lower noise floor. The dynamic range is realized in a higher maximum input level of +6dBV for the -10dBV setting and +20dBu for the 4dBu setting. Certainly looks better. The crosstalk shows a very respectable -100dB.

A few members around here have them. I don't know if anyone has critically tested one in a full range situation.

brucek


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## Guest (Nov 28, 2006)

Thanks for your reply again Brucek. This is like a mods private chat 

Yes, if as you say the DR is accurate that's actually reasonably respectable. However, I would still be suspicious of the quality / transparency of the converters. 

The lower crosstalk figure would certainly help with imaging though.

When time is a bit freer (hmmm...like that's gonna happen soon lol) I might get a 2496 in and do an a/b although with the amount of trapping I'm installing I expect not to need the FD much longer anyway and then I can eleminate another stage of degradation. 


thanks again for providing me with some answers and food for thought.


Matthew


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