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

David, I'd be skeptical about Sean's advice on simple rubber footers. If you truly need greater bass warmth, trial the IsoAcoustics Gaia footers. I found they were outperformed by the Revopods, but in a situation where bass is MIA, they could be the ticket.

I've managed to remove the sub amps and will send them out today. It was a bit of a challenge pulling them out due to the glue tape! I was surprised how tiny the RCA cables from the speakon inputs to the amps are. Flies in the face of the massive audiophile cables everyone puts on their subs these days. 

Perhaps this is actually an ideal time to play around with toe in, as I'll be without the bass output for a couple of weeks. Based on my listening so far, I thought that the Mk4's in my room would benefit from a bit less toe-in, so it's good to hear your input on that, Phil. I'll try your suggestion of some older recordings. I've got some great jazz from the 50s. Interestingly, I asked Sean about this and he said that the ideal positions he has found in various setups with the Mk4's have ranged from toed-in from as extreme as 2 feet in front of the listening position to some distance behind, usually no more than a couple of feet. He estimated 1/10 times directing the tweeters in front of the listener, 4/10 directly at the listener, and 5/10 behind. I always had the Mk1.5's pointed right at my ears, but notice that these new speakers aren't disappearing as well my old ones in that position, with the frequency spectrum tilted upwards (a little too much high end content in comparison to the mids). 

Marc, I was just looking at those footers! The company is based in Ontario, about an hour from where I live, though I think they're actually manufactured in China. Crutchfield carries them and has an easy return policy, so it's a no risk proposition to give them a go. I'm just waiting to hear back if they have the alternative threads (looks like the Zu's are 3/8"-16, which isn't included in the box). 

David

David,

The IsoAcoustics Gaia footers are rated for speaker weight up to 70 lbs per set. Definitions well exceed that, so the isolating compound may not as effective under greater mass.

An alternative that is effective for me is from Herbie's Audio Lab:

https://herbiesaudiolab.com/collections/loudspeaker-rack-decoupling-and-isolation/products/cone-spike-decoupling-glider?variant=12645103468599

Under Defs you can use either the regular or giant size, and the titanium spike receptor generally sounds best. This simply puts an isolating compound under the spikes.

Phil

Hey Phil, 

I actually have older spike receptors from Herbie's that I've been using with BDR cones, similar but different to the one's to which you linked. But in the interest of trying something new, I've ordered the IsoAcoustics Gaia's. I learned they actually come in multiple different sizes. The Gaia III's can only handle 70lbs per set, but the I's are rated up to 220lbs. I managed to negotiate a good deal from a store I've gotten a lot of pro audio gear from in the past, so I'm going to give them a shot. The manufacturer also agreed to send me the correct thread adapters directly. I'll let you know what I think about them!

David

David, I thought Phil didn't have that right. Yes, the Gaia I's are the ticket. You will certainly hear a different character in the bass. Whether that's ultimately for you...

I did try GSM's subs settings of 46Hz and 9/10 Level, but in the end found I was better off sticking w my current 38Hz and 6.5/10, as guided by Phil.

I may experiment w toe in. I sit 15' from my Zus, and they cross 3' behind me, much flatter than I initially had them, or the Def 2s before.