Added A Second Subwoofer To System

musicality,

Yes, I'm running my Lumina III's full range.  

My subs crossovers are set just below 60hz.

I'll try setting the subs lower and bringing up the volume as you suggested. 

Thanks for the response. 

What possibly happened is you smoothed out the bass so it is less prominent and more blended. It only sounds lower because it is smoother.

Not sure i can offer anything revelatory, but I’ve experienced variances in where I needed to set the volume knob to achieve pleasing spl and it was always due to room acoustics one way or the other.

I know my tracks and the volume where they sound right—historically.  After moving my seat and/or my speakers it’s apparent if something sounds louder or lower at that historic volume knob setting.  Aside from moving into or out of room nodes or null that could cause a volume change, a tonal change can lead to a perceived change in spl, I’ve always imagined.  We’re more sensitive to midrange, for example.  A bump or null in that region due to acoustics could affect our perception of volume.  

I added a sub only a couple of months ago and very much expect to add a second one later this year after I remodel my room.  I only played around with one spot before settling into the current placement so I’m out expert, but it’s tempting to suspect that corner placement would give a higher spl compared to mid-day sown the side walls?  I found my spot so quickly because my dealer gave me great guidance and I have an integrated amp with built in XO’s that makes sub optimization easy.  I cross at 50hz.  Subs play from 50 down and mains from there up.

I’d like to know if you think the tonal balance (aka, flatness of frequency) is better with subs out of the corners.  I recently improved my acoustics but didn’t move the sub, mans or my seat and it created what I call an imperviousness to volume.  I can crank it and it goes louder but the strain does not increase.  It refuses to lose composure.  But unlike what you are relaying, it is not like I’ve lost hearing and need to raise the volume.  It sounds great low but also loud.  I can enjoy it louder than before, I suspect, because I addressed some nasty pressure wave.  As I said earlier…it’s always acoustics.  And subs are as much acoustics derives addressing room pressure as they are “bass adding devices”. In fact, depending on the LF capability of ones mains, subs are much more the former than latter.

I’m trying to say that just because you can tolerate a higher volume setting or actually prefer it, doesn’t mean it’s not as loud.  Perhaps an annoying pressure (frequency) imbalance has been addressed.  Only you can assess that.  When we’re in a vehicle that feels like it’s going 50 when the dash says 85, we know that’s just our perception relative to how  85 feels in vehicles that are noisier and vibrates more. 

You most likely reduced some resonance that you were perceiving as additional volume.  It's unlikely that the volume of the primary content itself is reduced.

My 3 subs are integrated in a way that boosts certain frequencies and attenuates others which were "boomy" because of room acoustics.

When the subs were adjusted to cancel out (attenuate) certain frequency peaks, the overall volume appeared to go down. But the other frequencies were allowed to come forward, no longer obscured by peaks from 20-300 hz. 

There's no substitute for measuring these things, in my opinion. The free REW Wizard program plus a $100 Umik is one indispensable way to do that.