# Subs dial-in for HT and 2 Channel Audio?



## oris98 (Jan 15, 2007)

Hi all, I am very need to room treatment and hope someone can give me some advice on my following questions. My audio room is for both 2 channel audio and HT use. I have a pair of subs currently using for both 2 CH and HT. My room size is 17'x17' (bad room dimension). I have some DIY 4" bass traps at the corners and 2" on the first reflection point. The valvet screen curtain on the front wall and one valvet curtain on the side wall. 
I have now purchased a BDF 1124P a Galaxy 140 SPL/mic and the SB Live 24 USB sound card with the required cablings and adapters. 

Can I use my BDF to measure the freq. response with both subs running in stereo mode ? or should I do it one first and tune the BDF correctly before I toss in the second sub and fine tune it afterword ? 

My 2Ch setup is going through my preamp and my HT setup is going through a separate receiver. My subs has 2 inputs (2CH and HT). Can I somehow using 1 BDF to eq for both 2Ch and HT setup ? The only connection between 2ch system and my HT system is my 2CH power amp has both RCA (for HT) and XLR for (2ch) switch. When I play movies, I just flip the switch to RCA and accepting signal from the receiver directly for hte L/R channels.

For 2 ch, I hear boomy when I turn the sound level higher.

Many thanks in advance..:innocent:


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

> Can I use my BDF to measure the freq. response with both subs running in stereo mode ? or should I do it one first and tune the BDF correctly before I toss in the second sub and fine tune it afterword ?


Based on your description of your room and system, I assume you have a symmetrical room and the two subs situated near the speakers? If that's the case, then the subs probably have identical or near-identical response. Still, I'd measure each one separetly, and both together.



> My 2Ch setup is going through my preamp and my HT setup is going through a separate receiver. My subs has 2 inputs (2CH and HT). Can I somehow using 1 BDF to eq for both 2Ch and HT setup ?


Sounds like you're going to need a second BFD, as it is a two-channel device and can't accept four inputs.

Regards,
Wayne


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## oris98 (Jan 15, 2007)

Wayne A. Pflughaupt said:


> Based on your description of your room and system, I assume you have a symmetrical room and the two subs situated near the speakers? If that's the case, then the subs probably have identical or near-identical response. Still, I'd measure each one separetly, and both together.
> 
> Sounds like you're going to need a second BFD, as it is a two-channel device and can't accept four inputs.
> 
> ...



Hi Wayne,

Unfortunately my room is not symmetrical. There is an openning 6' on the left rear corner. I installed a solid core french door to enclosed that opening which make the room not symmetrical. The subwoofer is located about 9' from the front wall and 5' from the speakers one each side. Each sub is 1' from the side wall. Also from the front wall left side there is a 3'x3' column on front left corner which make the speakers cannot placed symmetrically in the room too. BTW, my room is 8' ceiling. 

Regarding the BDF, it has both XLR and 1/4" plugs input, can I switch to XLR if I want to use my preamp for 2ch audio and switch to 1/4" plugs input if I want to use my receive for HT ? 

Thanks again..


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

I would call a room symmetrical if the walls are parallel to each other, and the ceiling parallel to the floor. E.g. "shoebox" dimensions, or something along the lines of a bedroom as opposed to a family room with a cathedral ceiling that's fully open to upstairs, kitchen, entryway, etc. Make sense? Every room has to have a door - that doesn't make it non symmetrical, in and of itself.  

That's not the same thing as not being able to place your speakers symmetrically in the room for some reason. If someone's subs are the same distance from the walls behind and to the side, then their placement is symmetrical. I can't tell for sure if yours are placed symmetrically or not, since you referred to "the subwoofer" in one sentence and "each sub" in another. Regardless, it's best to take measurements of them both together and separately.



> Regarding the BDF, it has both XLR and 1/4" plugs input, can I switch to XLR if I want to use my preamp for 2ch audio and switch to 1/4" plugs input if I want to use my receive for HT ?


As long as you don't mind manually swapping out the cables. There is no "switch" between the XLR and 1/4" inputs. They are most likely internally connected, and as such there would be no isolation between the two systems if both were connected to inputs at the same time.

Regards,
Wayne


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## oris98 (Jan 15, 2007)

Hi Wayne,

"Regardless, it's best to take measurements of them both together and separately." 

Are you referring to measure both subs together and then also measure the response individually as well. Now, does it means I have to average out the measurement (L+R, L only and R only) as the final average result and use it as a base line to start tuning with REW ?

Thanks again.


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

Take a measurement with the right sub only. Then the left only. Then turn them both on and measure again. IOW, you’re going to have three separate graphs. You might need to re-calibrate REW for each reading, but as long as you don’t get a “signal weak” or “clipping” indicator, you’re fine. :T

Regards,
Wayne


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