# New BFD 1124P Owner Needs Help



## samhain (Feb 19, 2012)

Hi,

I received my unit today and it had no manual, downloaded the manual online and not really helped.

I have a Yamaha RX-Z11 amplifier and from this at the moment I have a single RCA connection between the amplifier and the subwoofer. I am assuming that I now need to put the BFD between the amplifier and the subwoofer.

Am I right in saying that it is; 

1. Single RCA from RX-Z11 to 1/4" input on the back of the BFD. Which input is it? Is there a left and right input on the BFD, so what happens with a mono signal? 

2. 1/4" BDF output (which one) to the subwoofer RCA


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## wgmontgomery (Jun 9, 2011)

I have never used the piece in question, but here's a link that should contain all the answers you seek:

http://www.hometheatershack.com/forums/bfdguide/

If you are still confused, don't fret. Post any questions unanswered by the thread; we'll get it hooked-up correctly!!


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## wgmontgomery (Jun 9, 2011)

I looked over the thread that I posted above; it seems to me that you take the mono subwoofer/LFE output FROM your Yamaha to the LEFT _input_ on the BFD. Then take the LEFT _output_ FROM the BFD TO the subwoofer's _input_ (you'll probably need RCA to 1/4 inch adapters).


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

samhain said:


> Am I right in saying that it is;
> 
> 1. Single RCA from RX-Z11 to 1/4" input on the back of the BFD. Which input is it? Is there a left and right input on the BFD, so what happens with a mono signal?
> 
> 2. 1/4" BDF output (which one) to the subwoofer RCA


That is correct, Sam. Take your pick, you can use either input of the BFD – does not matter.

Regards,
Wayne


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## wgmontgomery (Jun 9, 2011)

Just make sure that if you use the_ left input _you also use the _left output_...if what I read is correct.


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## samhain (Feb 19, 2012)

thanks, would someone kindly link me to products that I could use for this purpose.

I have seen a few dual ones, but I can't quite get my head around the dual when it is a mono signal, is it the case that one size simply is redundant and is not connected to anything with a dual cable?

Thanks


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

Since we’re talking about a single (mono) signal from receiver -> equalizer -> subwoofer, a dual (stereo) cable is not needed. That said, you could simply get a dual cable and separate the two halves, and then you’d have two mono cables – i.e. everything you need. You should be able to find an RCA to 1/4” cable at your local guitar shop.

Regards,
Wayne


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## wgmontgomery (Jun 9, 2011)

+1 on buying a stereo version and separating it into two haves. Just make sure that it has two RCAs and _two_ mono 1/4 inch plugs; not a stereo 1/4 inch plug.

I agree that the local music/guitar shop should have what you want, but here's the link that you requested:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=090-285

All that you should need are two of these (one on the BFD's input, one on the BFD's output) and a couple of regular RCA cables.

Good luck! Let us know if you need more help!


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## samhain (Feb 19, 2012)

Got everything I need and hooked up the BFD and it seems to be working ok. I haven't tested anything or changed anything yet so just using it to see if working. There doesn't appear to be any hum although I got the sub pop when I switched sub on before the BFD.

Once the unit is set up do the front lights ever go off as they are quite bright. I see the store light flashes but I am assuming that is just because I am playing with it and once it is set up this light won't flicker in normal use?

I am getting some conflicting messages from other forums, if lets say I had lots and lots of peaks which I can reduce but at the lower end it drops away quite dramatically; will the laws of physics still kick in that a 3db boost at 25Hz will require double the power from the amp? Will it damage the amp with sustained use even if it has been dropped significantly elsewhere.

Some say there won't be a problem others say it will


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## wgmontgomery (Jun 9, 2011)

I have never used the BFD, but there's an entire thread devoted to it here: http://www.hometheatershack.com/forums/bfdguide/

I hope that you can find an answer there; if not someone will come along who knows. Good luck!!


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

Hey Sam,



samhain said:


> I got the sub pop when I switched sub on before the BFD.


Most people just leave the BFD on all the time. Alternately, you’d need a power sequencing device that would turn on the BFD before sub.




> Once the unit is set up do the front lights ever go off as they are quite bright. I see the store light flashes but I am assuming that is just because I am playing with it and once it is set up this light won't flicker in normal use?


You can put some dark window tint or black electrical tape over the lights. Yes, the store light will stop flashing once you store the settings.




> I am getting some conflicting messages from other forums, if lets say I had lots and lots of peaks which I can reduce but at the lower end it drops away quite dramatically; will the laws of physics still kick in that a 3db boost at 25Hz will require double the power from the amp? Will it damage the amp with sustained use even if it has been dropped significantly elsewhere. Some say there won't be a problem others say it will


Yes, there is a lot of nonsense that floats around when it comes to equalizing subwoofers.

When you say “lots of peaks which I can reduce” that indicates to me that you’ve been hearing people say that sub EQ should only apply cutting filters. This is a common and erroneous misconception. The fact is, *any* equalization will place additional demands on both the subwoofer driver and amplifier. There’s no free lunch.  This post explains why.

Regarding boosting below 25 Hz, that depends on the extension of your sub. If response is dropping like a brick down there, then it’s foolish to try to shore it up with equalization. However, if response is dropping fairly gradually, you could get a bit more extension with equalization, as long as it’s a sealed sub, or a ported sub with the port tuned below that point (you aren’t supposed to boost below a port’s tuned frequency). Whether or not that will damage the amplifier - well, that depends on the amp and the way you use it.

For instance, if you have eight 18” subs powered by 12,000 watts of amplification in a 1000 cu. ft. room, you can use EQ boost to your heart’s content. However, if you have an 8” sub with a 75 watt amp – probably better not do it. But even with that sub it would be fine if you never used it for anything louder than background music.

Make sense? 

Regards, 
Wayne


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## samhain (Feb 19, 2012)

Thanks Wayne most helpful.

I have the SVS SB13+ so a beast of a sealed subwoofer albeit not in the realms of a decent 15 or 18" woofer.

I am getting really confused when reading up on REW. I can see there are two ways to test and set up the subwoofer, 1 manual so you run a test tone and place reading into a spreadsheet or using REW connect a MIC, soundcard and run test tones through your amp to get a reading picked up by the mic.

Am I right in saying that no matter which way you go, in order to smooth peaks or increase dips then pressing the buttons on the BFD is the only way to programme any change. Actually I have noticed the MIDI link. Will this only work with 1.4 firmware?

I am sure I still have an external USB sound card in the store which I could use so to get up and running do I need;

1. ECM8000 from Cross Spectrum LAbs
2. USB sound card with line in and line out (How do I know if the sound card has an internal microphone preamp?)
3. USB midi cable to connect PC/laptop to 1124P (recommendations please, the one quoted in the REW help appears to be discontinued)
4. I have an RS analogue SPL meter
5. RS SPL calibration file?

I need to get my soundcard out of storage but I think it's the old EXTIGY by creative which has line in, mic in and headphones on the front and midi in and out on the back

Thanks


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## samhain (Feb 19, 2012)

Got my bfd in the food chain and have set the gains so that the green lights flicker upwards to below clip. No buzzing or other nasty noises so I think I am lucky.

I have not set any EQ filter either boost/cut or bandwidth yet. I really don't know where to start. I know I have a peak at 50Hz by about 10 db. Either side seems quite flat in comparison (60Hz and 40Hz). What should I press to set it at.

Also at the lower end as with most subs it drops away at 20Hz any ideas what to set at and process to do that

Thanks

Stewart


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

Hey Stewart,

It’s not necessary or advisable to run the BFD’s inputs all the way to the top. Best to leave some headroom and set them for something like -10 to -12. For instructions on how to operate and set the BFD, see the  BFD Guide.

Regards, 
Wayne


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