MY99 2.5GT

Ported subwoofer boxes are usually perceived as boomy. Personally I think that usually suits movie soundtracks well. Tight accurate bass response is usually a characteristic of sealed subwoofer enclosures. Passive radiator boxes are kind of a mix. Generally my friends that want to hear an accurate reproduction of instrumental content such as jazz, orchestral, big band, opera, tend to favor sealed subwoofers.

Sorry for the delay in responding. I traced the issue back to a bad output phase on my old Yamaha RX-V667. Shortly after posting I couldn't get any signal from the Sub-Out RCA jacks. Unfortunately it took my old BASH 500 amp with it somehow and screwed up 2 brand new amps that I ordered from Amazon (Thankfully I was able to return them). I now have a new Denon Receiver and a pair of iNuke 1000 amps that work perfectly. Sadly my Cerwin Vega VMax 15.2 car speakers in home theater boxes isn't too impressive in a large room so I'm thinking of upgrading to a single (or potentially dual) Stereo Integrity HST-18's and an iNuke 6000once they become available for order again.

The speaker wire is connected to the twist poles and are wired correctly. I installed a ground loop isolator on the sub woofer preamp output rca connection from receiver, same hum results. I tried plugging the Rolls into a battery backup to eliminate any potential power line noise, same hum results. I just tried a different rca cable, same hum result. I also tried bridging the amp by rewiring the speaker wire output, changing dip switches appropriately only to find the same hum is present. I think I'm done fooling around with this thing. It's going back to amazon.

Found this: "Let's explain the signal ground lift in more detail. The hum current in a ground loop flows in the audio cable shield, and can induce a hum signal in the signal conductors. You can cut the audio cable shield at one end to stop the flow of hum current. The shield is still grounded at the other end of the cable, and the signal still flows through the two audio leads inside the cable. So, to break up a ground loop, disconnect the cable shield from pin 1 in line-level balanced cables at the male XLR end (Figure 4). You can either cut the shield, or plug in an inline audio cable ground-lift adapter." From here: https://www.google.com/url?sa=t&source=web&rct=j&ei=t04fVenoF8XvarLCgdgM&url=https://cdn.shopify.com/s/files/1/0247/3799/files/preventing_hum_and_rfi.pdf&ved=0CB8QFjAA&usg=AFQjCNGBoHQXnCinx56z1qCWfDUAixe_tg&sig2=KQYtdWoSysuT4umk74T9VQ

Receiver: Yamaha RXV663 - http://usa.yamaha.com/products/audio-visual/hifi-components/stereo-receivers/rx-v663_black__u/ Amplifier: Behringer EP4000 - http://www.amazon.com/gp/product/B001U5JFNM/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 Line Converter: Rolls MB15b -http://www.amazon.com/gp/product/B0002IL4B4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 Cables: http://www.amazon.com/gp/product/B00KO8VY4O/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 2 - RF7ii 1- RC64ii 4- RS400 I wanted to run dual subs so I took the plunge and bought an EP4000 along with a pair of RCA to XLR cables. After plugging everything in I thought the input phase of the amp was defective because even with the gain at max no sound was coming out. After further research, and toggling dip switches on the amp, someone from Parts Express recommended that I buy a line converter. I ordered the Rolls MB15b from Amazon along with male/female XLR cables. I plugged everything in today like this: Receiver Subwoofer Out RCA -> Rolls MB15b -10db in -> +4db XLR Out -> Behringer XLR input Behringer pins are as follows: Right - 1,3,8,10 Left - 2,4,5,6,7,9 gain on the behringer turned all the way up Receiver side crossover set to 80Hz, receiver's subwoofer level turned all the way up, level on the Rolls turned half way up, the subwoofers are audible but very weak and I'm hearing audio well above 80Hz through the woofers. An audible hum is present that seems to increase exponentially when turning the level up on the Roll's. As well, with the level at 100% on the Roll's, Behringer at 100% gain, Receiver's subwoofer level at 100% my pair of Cerwin Vega VMax 15.2 woofers don't move or play even close to the same level as when driven by a cheapy BASH500 plate amp. Not sure what is going on, any help is greatly appreciated as I'm about to return the behringer and rolls in favor of something like the Dayton SPA1000.