Question About Best Practices For Setting Subwoofer Level In Dirac

[SadMonster]

In a non bass controlled system where 2 subwoofers are simply daisy chained to 2 speakers and it is basically acting as a full range stereo system, when setting subwoofer levels with band limited pink noise, does Dirac best work if the subs and monitors are matched in db, or is it better to get the sub as close as possible to your desired Dirac target curve (Ie: +6db in bass region) through spl meter measurements before Dirac does it’s magic?

Sorry, I know this is a very specific question, but if anyone has any science based knowledge on this, it would be appreciated.

Setup is
Stereo Output > 2 JBL LSR Subwoofers > 2 JBL 4329p,

 

[janbth]

I would think turning up the subs to match the +6dB in the bass region before running Dirac is the better choice. The idea is that it’s better to have Dirac chop off the peaks in the response in this region, rather than boosting.

 

[SadMonster]

Dirac responded to me directly and said this

"
Hello!

I’d suggest level matching the subs to the mains.

If you pre-boost the subs to already match your desired target boost (e.g., +6 dB), then Dirac may find the subs too loud relative to the mains, pull them down, and reduce headroom
Eventually, it may force itself to work “against” an imposed slope you already baked in

Also, if feasible, I'd suggest using a Y adapter instead of daisychaining.
When you daisy-chain the first sub’s output stage feeds the second and this can introduce additional noise, impedance changes, or signal-level inconsistencies.
Some subs output a filtered or phase-altered signal on the “thru” output.

When you Y-split both subs receive the exact same signal from your preamp/interface
You avoid unpredictable circuitry in the daisy chain
Gain staging is more consistent.

Kind regards, and good listening!"

 

[kyuu]

I mean I think the Dirac rep is correct, but I can't be sure as I'm unclear on your setup. What do you mean your two subwoofers are daisy chained to your speakers?

 

[SadMonster]

I mean I think the Dirac rep is correct, but I can't be sure as I'm unclear on your setup. What do you mean your two subwoofers are daisy chained to your speakers?

Dirac output L and R to two different subwoofers each subwoofer using built in 80hz crossover output into a speaker.

 

[janbth]

So Dirac only sees L and R speakers, and no subs? Then Dirac will not be able to pull down the subs separately. Are you sure the Dirac rep was aware of your setup?

 

[SadMonster]

Yes that is correct

Hmmm now I'm worried I only told them what I told you

 

[MarkHH]

Dirac will pull down the bass region, which in this case comes from the subwoofer part of the “virtual” speakers, so IMHO their response makes sense.

 

[carlosatl]

So? Title still calibrate the system as a whole pair of speakers, will it do a good job that way still?

 

[DWPress]

I would do as Dirac suggests then listen and measure to be sure. Dirac can so some funky things with bass even with the vanilla version.