# BFD (1124p) input clipping, even at +4 setting



## lukehale (Jul 31, 2012)

First post here, having a bit of an issue...

I don't know if perhaps my H/K AVR254 just has REALLY hot pre-outs, but I am having trouble getting the level low enough to not clip on the BFD. Just as an initial test I am using the built in test tones (which seem to be just pink noise, with adj volume level). I have the subwoofer level set to -10 in the AVR settings, and I also have the LFE trim set another -10dB, and I still cannot get past -10dB on the volume level without the BFD clipping. Anything from -9 and up on the volume control results in a solid red clip light, not just blinking. I definitely can get to a higher volume level with the switch set for +4 than -10, but should it really be that hot of a signal? 

Are the Harman Kardon pre-outs really that hot of a signal? or is it maybe the test tones are boosted to clipping? Anyone else with an H/K have this issue? 

Any help would be wonderful.


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

Hey luke,

First, welcome to the Forum!

I doubt anyone here has any inside information on HK’s output signal strength. That said, it's not unusual for a receiver's sub output to be considerably hotter than that of the main channels (measured at the pre-amp outputs). The only solution is to set the BFD to +4, reduce the receiver’s sub output to a level that peaks the meters no higher than yellow, and turn up the sub’s volume control as needed to restore the output lost at the AVR.

BTW, if you're interested look, for the gain structure article in my signature. In it you'll find a simple procedure you can follow to measure the output signal of your AVR.

Regards, 
Wayne


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## lukehale (Jul 31, 2012)

Thanks for the response. Sadly, I already have the subwoofer level in the AVR as low as the settings allow, and it still is too hot. I can't get my other speakers up to the level I want them (reference) due to the BFD clipping so soon. The only other solution I can think of is to perhaps buy a line attenuator? Any downsides to using one of those to lower the voltage going into the BFD?

Thanks again


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

No issues, as long as the attenuator has linear frequency response (i.e. doesn’t roll out the low end).

Just curious, are you having this problem with regular program material or just the HK’s test tones? Also, are you using outboard amplifiers for the main channels?

Regards, 
Wayne


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## jtalden (Mar 12, 2009)

lukehale said:


> Thanks for the response. Sadly, I already have the subwoofer level in the AVR as low as the settings allow, and it still is too hot. I can't get my other speakers up to the level I want them (reference) due to the BFD clipping so soon. The only other solution I can think of is to perhaps buy a line attenuator? Any downsides to using one of those to lower the voltage going into the BFD?
> 
> Thanks again


For a given SW SPL level, the line level provided by the AVR to the BFD will be a function of the "Volume/Level" of the SW amplifier. This means that increasing the "Volume/Level" control on the SW itself will reduce the signal provided from the AVR and through the BFD. 

[It also means that for a given SW SPL level, the setting of the AVR LFE level control will have no affect on the signal level to the BFD.]

Do you already have the "Level/Volume" control on the SW amp at a reasonably high level?


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