Serious Sub trouble

[savantstrike]

So I just bought two Dayton Reference 15 HF's, and have been in the process of building two 3.3 cu foot boxes for them. While the boxes are coming along nicely, I decided I'd do a free air test of one of the drivers to get a taste for what to expect. Big problems, I'm getting a constant buzzing out of the drivers. This needs some attention, and I'm looking for assistance in troubleshooting it. Amplification setup is as follows:

I got a brand new Behringer EP 2500 on Ebay to power these subs. It was recommended by people on this forum, so it had to be good, and I liked the look and price. I also bought an ART cleanbox (also new in box) on ebay because I did not want to have to struggle with the conversion from RCA to pro sound 1/4" or XLR. This too was recommended.

You guys know your stuff, the Behringer was nice, and noise level didn't bother me (maybe it'll get louder under heavier load, but then everything else will be louder too). When I first got my cleanbox and amp, I ran my 25 foot Dayton shilelded RCA subwoofer cable to the place the Behringer will reside in, and I connected it to the preamp output for the right front on my Yamaha HTR 5760. I then plugged the Dayton shielded sub cable into the cleanbox and plugged a 1.5 foot dayton balanced XLR microphone cable from the cleanbox to the Behringer. I set all the settings in the Behringer to make it a mono signal, and hooked up a spare 8 ohm bookshelf I had lying around to make sure there was sound, and there was. Sound quality was good, as (to me) it sounded almost the same as (and at the time I thought the same as) this speaker sounded on the B channel of my Yamaha. I then proceeded to keep all the cards that came with my cleanbox and then I threw out the plastic crap it came in.

A few days later I did this same setup, only I connected one of my 15" subs to the amp, and connected the preamp output to the LFE channel on my amp. Sound came out, so far so good. Then I paused the music. No good, constant buzzing (probably masked by the fact that I had music playing before this point).

I then plugged the UPS that the amp was in (didn't have any spare surge strips) into the UPS my reciever is on to try and see if it was a ground problem. Still buzzing. Furthermore, the cleanbox itself claims to stop this type of buzzing, so I think I don't have a ground problem.

What's going on here? What am I doing wrong?

Is there another way for me to just connect the preamp output directly into my Behringer via XLR or 1/4"?

Any and all help would be very appreciated.

[billfitzmaurice]

> Is there another way for me to just connect
> the preamp output directly into my Behringer
> via XLR or 1/4"?

<A HREF="http://www.rane.com/note110.html">http://www.rane.com/note110.html</A>

[jyourison]

> So I just bought two Dayton Reference 15
> HF's, and have been in the process of
> building two 3.3 cu foot boxes for them.
> While the boxes are coming along nicely, I
> decided I'd do a free air test of one of the
> drivers to get a taste for what to expect.
> Big problems, I'm getting a constant buzzing
> out of the drivers. This needs some
> attention, and I'm looking for assistance in
> troubleshooting it. Amplification setup is
> as follows:

> I got a brand new Behringer EP 2500 on Ebay
> to power these subs. It was recommended by
> people on this forum, so it had to be good,
> and I liked the look and price. I also
> bought an ART cleanbox (also new in box) on
> ebay because I did not want to have to
> struggle with the conversion from RCA to pro
> sound 1/4" or XLR. This too was
> recommended.

> You guys know your stuff, the Behringer was
> nice, and noise level didn't bother me
> (maybe it'll get louder under heavier load,
> but then everything else will be louder
> too). When I first got my cleanbox and amp,
> I ran my 25 foot Dayton shilelded RCA
> subwoofer cable to the place the Behringer
> will reside in, and I connected it to the
> preamp output for the right front on my
> Yamaha HTR 5760. I then plugged the Dayton
> shielded sub cable into the cleanbox and
> plugged a 1.5 foot dayton balanced XLR
> microphone cable from the cleanbox to the
> Behringer. I set all the settings in the
> Behringer to make it a mono signal, and
> hooked up a spare 8 ohm bookshelf I had
> lying around to make sure there was sound,
> and there was. Sound quality was good, as
> (to me) it sounded almost the same as (and
> at the time I thought the same as) this
> speaker sounded on the B channel of my
> Yamaha. I then proceeded to keep all the
> cards that came with my cleanbox and then I
> threw out the plastic crap it came in.

> A few days later I did this same setup, only
> I connected one of my 15" subs to the
> amp, and connected the preamp output to the
> LFE channel on my amp. Sound came out, so
> far so good. Then I paused the music. No
> good, constant buzzing (probably masked by
> the fact that I had music playing before
> this point).

> I then plugged the UPS that the amp was in
> (didn't have any spare surge strips) into
> the UPS my reciever is on to try and see if
> it was a ground problem. Still buzzing.
> Furthermore, the cleanbox itself claims to
> stop this type of buzzing, so I think I
> don't have a ground problem.

> What's going on here? What am I doing wrong?

> Is there another way for me to just connect
> the preamp output directly into my Behringer
> via XLR or 1/4"?

> Any and all help would be very appreciated.

That 25 foot cable will pick up all kinds of noise, especially if you have flourescent lights and/or dimmers. Try a shorter cable and turning off lights and appliances to see what may be causing the buzz. Could be a bad cable, so try another as well.

Also, try keeping the amps/sources on separate circuits (i.e. different hot sides from your mains). Lift all grounds for a check, disconnect your TV cable if it's in the system . . . blah, blah. You get the idea.

[Paul O]

> When I first got my cleanbox and amp,
> I ran my 25 foot Dayton shilelded RCA
> subwoofer cable to the place the Behringer
> will reside in, and I connected it to the
> preamp output for the right front on my
> Yamaha HTR 5760. I then plugged the Dayton
> shielded sub cable into the cleanbox and
> plugged a 1.5 foot dayton balanced XLR
> microphone cable from the cleanbox to the
> Behringer.

The right way to utilize the cleanbox is to make the unbalanced RCA link as short as possible, in other words put it right behind the AVR. Then use a 25' balanced XLR cable to connect the cleanbox to the amp.

[philiparcario]

> The right way to utilize the cleanbox is to
> make the unbalanced RCA link as short as
> possible, in other words put it right behind
> the AVR. Then use a 25' balanced XLR cable
> to connect the cleanbox to the amp.
use very short cables, turn off everything in the homes except the audio circuit. get a power strip cheap and cut the ground plug, have a second power strip with a good ground plug. plug both power strips into the same outlet / plug everything into the cut strip with no ground/ if the buzz stops pull on plug out and put it in the good power strip/ with luck you can find what component needs the ground lifted? I want to know how this project turns out / did you make the filter with the resistors and the caps? phil

[ren]

> I got a brand new Behringer EP 2500 on Ebay
> to power these subs. It was recommended by
> people on this forum, so it had to be good

That's your trouble right there. Listening to (many of the) people on this forum.