diminishing subwoofer signal

[viseral audio]

I have a Yamaha rxa3070 set up with two subs using sub pre-outs 1 and 2 using mono signal. After setting up both subs to the best of my ability with placement, levels, and distance settings to get highest db levels played together, I noticed bass was stronger with just front sub playing switching off second sub in receiver menu, so after much experimenting thinking back sub must be cancelling because of phase issues I turned volume down as far as possible (-60 db ) on rear sub and again played good bass music and switched between one sub and two and the bass level still changed about 3db, less with two subs selected. Im going to assume its because when you select two subs mono it splits signal strength in halve? anybody else notice this?

 

[everettT]

What subs?

 

[lovinthehd]

Does it do the same with different placement of subs? Just how are you measuring?

 

[viseral audio]

front subs are turbo sound placed center between mains, rear is svspbultra16 in rear corner, doesn't matter placement, you can actually see different level in meter on power amp for front subs when switched from use second to just one.

 

[lovinthehd]

Not familiar with turbo sound subs....they're passive using an amp with vu meter? How are they wired to amp?

 

[viseral audio]

yes they are passive running them with my carver Tfm 75 wired with xlr cable

 

[viseral audio]

the turbosound are a high end reinforcement horn loaded, handling frequencies from 120hz to 40hz

 

[lovinthehd]

Each on their own channel?

 

[viseral audio]

all subs are running mono signal out of Yamaha

 

[lovinthehd]

Yes, subs are provided mono signals by the avr but that's not the question, each on their own channel or bridged etc? How exactly are subs connected to avr? You have no ability to measure response?

 

[viseral audio]

sorry lovinthhd, front subs are fed to the carver amp each on there own channel using a splitter out of sub pre out number 1 on Yamaha

 

[lovinthehd]

sorry lovinthhd, front subs are fed to the carver amp each on there own channel using a splitter out of sub pre out number 1 on Yamaha

Could be one channel gets more power when the other's not in use? Dunno. I think you're needing measurement gear to really figure things out....

 

[Drunkpenguin]

My 2 svs pc13s sound best with one of them at 180 degrees. With both at the same level base is almost non existentst.

 

[mtrycrafts]

I have two passive subs on opposite sides on a more or less diagonal. It is like this.
If you run a frequency response on one and compare to the fr on the other run by itself, you will have a number of bands that are grossly different
as the room dictates the peaks and nulls.
Then you add both in, without any EQ to fix the original response and you will have yet another response at the listening position.
So, it is not whether you have more power to one than the other as you may or may not but the room is affecting it a great deal.

Now to get the best with both running is a huge chore as at each frequency you will have to either increase that frequency or decrease it to have a smooth curve.
There is a setup with a Behringer EQ that can do it but it is not that simple of a process.

 

[lovinthehd]

My 2 svs pc13s sound best with one of them at 180 degrees. With both at the same level base is almost non existentst.

You're referring to phase I assume?