BFD Clipping

**duecer32** · **03-15-09, 04:57 PM**

I am using a Yamaha RX-V659 and the BFD. I have my sub level adjusted to -10db(Max cut) on the Yamaha and when I turn the volume output to -5db from reference the red clip lights are going crazy on the BFD. How can I further reduce the signal to the BFD to allow me to turn up the volume higher?

**Wayne A. Pflughaupt** · **03-15-09, 06:10 PM**

Did you change the BFD's rear panel switch to the +4 dBu setting?

Regards,
Wayne

**duecer32** · **03-15-09, 06:28 PM**

Yes I did, I will be sure to double check that though.

**brucek** · **03-15-09, 09:56 PM**

Quote:

How can I further reduce the signal to the BFD

I'm having trouble understanding how a standard consumer level receiver, outputs signal that cause clipping with the sub trim turned all the way down. There's something not right.

What does your manual say is the output level of the sub jack?

brucek

**duecer32** · **03-16-09, 12:10 AM**

Ok, double checked my BFD. Both of the input level buttons are pushed in for the -10dbv as stated in the BFD guide. According to the manual my receiver puts out 4V at 1.7K ohm. I have the signal going to a RCA Y cable into the BFD if that would make any difference?

**brucek** · **03-16-09, 08:28 AM**

Quote:

puts out 4V at 1.7K ohm.

That's quite high for a consumer product. The standard for most consumer receivers is about max of +2dBV ( ~1.25vRMS) and nominal of -10dBV ( ~315mvRMS). This is the level that the -10dBV switch position assumes in the BFD.

The +4dBu switch position in the BFD assumes a max of +16dBu ( ~4.9vRMS) with a nominal level of +4dBu ( ~1.25vRMS).

So, you can see that your BFD would be better suited for the +4dBu switch position.

If no other information is given, it's hard to know at what trim position of the sub control on the receiver that the specification of 4volts is given in your manual. If we assume it's the output max at mid position (zero) of the trim, then if you have the trim at -10max cut, then you should not be able to clip the BFD using the +4dBu switch position.

brucek

**duecer32** · **03-16-09, 03:46 PM**

Guys, thanks for your help. I will be sure to give the +4 a shot when I get home. I'm wondering how many others are in the same boat and have kept the BFD at -10 and clipping. I'm not using anything fancy for a receiver, there's got to be millions of Yamaha's in use. Once I get this dialed in I will post some of my results. Thanks again.

**thewire** · **03-16-09, 04:07 PM**

Quote:

duecer32 wrote:

Guys, thanks for your help. I will be sure to give the +4 a shot when I get home. I'm wondering how many others are in the same boat and have kept the BFD at -10 and clipping. I'm not using anything fancy for a receiver, there's got to be millions of Yamaha's in use. Once I get this dialed in I will post some of my results. Thanks again.

Yes, I am guilty of having done that before.

The thread that you might have noticed in this forum was titled I don't understand the BFD clipping meter. Please help.

I never meant to run it in -10 setting regardless that it was the "FBQ" instead of the "BFD" because my subwoofers are THX certified meant to run at +4dBu and my pre/pro has 4v pre/outs. I was recommended to turn down the subs, but Andysu later clarified what I had been doing wrong after I had tried to sneek out of the thread..

**duecer32** · **03-17-09, 01:09 AM**

The problem is indeed solved with the +4 switch. Thank you again for the help. Now Im on to spend many hours learning and tweaking away.

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