Help me understand how to optimize bass on the Zu Definition Mk IV

For context, I am also a bass guitarist, so I do love some very deep low frequencies!

So when you get these the best you can then if you want a whole lot better get four cheap subs, place them near the walls spread asymmetrically around the room, and be amazed how deep and low and tuneful and focused the bass is with a distributed bass array.

Thanks for the great responses so far, very helpful!

Yes, these new MkIV's are in the same room and location as the previous speakers. Unfortunately, I am very limited where they can be placed, but the location worked very well before. They are only about 6" from the back wall and 2 feet from the side walls. Perhaps I was used to the walls reinforcing the bass so strongly with the 4 rear firing 10" woofers on the Mk1.5. Yes, the bass on the MkIV is tight and tuneful, but just pretty underwhelming so far in comparison (the down firing woofers are definitely functional). Hopefully I can get it dialed in, because it has left me with some buyer's regret, hoping for an upgrade, but feeling let down about the bottom end. For context, I am also a bass guitarist, so I do love some very deep low frequencies! 

Spiritofmusic, thank you for your very detailed post, appreciated! I will try some of those settings. I wish I could pull them out from the wall as you suggest, but it's just not practical at all for my space. Coincidentally, I also have a 150 yr old suspended wood floor, so I could play around with footers. I just put on the Black Diamond Racing cones that were on my last set of speakers. Have you found that the gap spacing to the floor is critical? In the manual, it suggests even 1/4" is sufficient, but at least one forum post I read said that bass didn't really begin to bloom until the speakers were 3" off the floor. 

As for my amplifiers, I don't think they are "bridged," but not 100% sure. They are Cary 300SE monoblocks, with a Cary SLP98 preamp in front, all run with unbalanced RCAs. One odd thing about the preamp is that it inverts phase, so you have to switch around the speakers cables, but I believe I have that sorted properly. 

Other thoughts are welcome!
David

By any chance is your amplifier either bridged or "fully balanced"?

From one of the writeups provided for the Def IV at the Zu site:

Definition Mk.IV is designed around conventional or parallel mode amps, bridged amplifiers are not recommended (black speaker negative leg of bridged amps will see the virtual ground node of the internal bass amp).

The same caution would presumably apply to fully balanced amps as well as to bridged amps.

Regards,

-- Al

Temixoch, the bass on the Def4 is certainly a different beast than on my Def2. I'm assuming the 1.5 is similar to the 2, w four 10" subs rear firing.

The trick to getting it right is to drop the Low-Pass Filter to 38-42Hz. I'm at 38Hz, as is Phil. It's critical not to allow subs output to bleed into, and thus smear, the mids FRDs.

At 38-42Hz, have the Volume at 5-7.
I'm at 6.5, but this is really room dependent.

Other settings w me are
PEQ Gain 3.75
PEQ Freq 31
Phase 0° (both switch and dial)

For me, the 2s were just overwhelming, I could never get them right. Yes, bass on the 4s seems less powerful, but it's tighter and more tuneful.

Get yr 4s a little into the room, they start singing here 5' from front wall, best at 8'. From side walls, 3-4'.

Then set Low Pass Filter to 38Hz, Volume at 5/10. Repeat tracks w Volume going up in increments to 7/10.

Then start again w Low Pass at 39Hz, vary Volume incrementally 5-7/10. Then start again at 40Hz, incrementally Volume 5-7/10. And so on.

At some point hopefully you'll hit on the right balance of extension, bloom and speed.

Another consideration is the 4s are down firing. Thus, footers on the Zus and type of floor makes a difference, more than the 2s.

In my old apartment w solid concrete floors, stock spikes or Symposium Rollerblocks really worked. Here, on my 150 yr old suspended timber flr w plenty of flex, Arya Audio Revopods on Panzerholz are the ticket.

I'll ask Phil to chip in.

So, room and location are the same as before?

First, the basics. Make sure all 4 woofers are working. :)

Next, placement. You might want to try the reverse speaker trick. Put the speaker in your normal listening location, and walk around the room until you hear the ideal bass. Then put the speaker there.