Sub suggestions please

Walnut is important in this case

JBL HDI-1200p, satin walnut is one of the finishes, is a 3000 dollar sub. It appears to be currently on what i think is a closeout sale for 1200...might as well hop on it. I certainly wouldn’t pay 3000 for it. The audioholics guys gave it a decent review, believe it has a relatively high quality low distortion driver in it. But, when a driver gets deeper down is when distortion parameters skyrocket (The Jbl factory jiggle guy played it safe...)

It won’t explore the deep low depths of your soul like a Rythmik F18, for example.(Nevertheless, don’t end up buying some trash just for the walnut finish. You could always put a walnut finish to a sub cabinet in your garage, y’know, i.e., with a good subwoofer.. It’s what the garage’s for...)

There are some great suggestions in this thread but, not surprisingly, nobody is mentioning the exquisite Perlisten line.  Perlisten has a low profile on Audiogon, perhaps because the company rarely submits its products for review.  But  make no mistake, these subs are pretty incredible, deep low-end extension (12 Hz with built-in bass boost), effortless, transparent transient response, extraordinary detail.

They're not cheap, starting at around $2000, and don't offer a ton of bells and whistles, but they cover all the bases most important to audiophiles -- especially SQ.  IMHO, they're definitely worth at least seeking out. 

These are available in Walnut.  

https://gr-research.com/product/finished-sealed-servo-subwoofer-single/

I am not sure why the walnut finish is so important, but buying a sub that performs well would be my first priority and then add your own finish and get what you really want I would think adding some walnut veneer would not be that difficult. Time consuming maybe but not difficult. The SVS subs offer a lot of bang for the buck and their customer service is said to be pretty darn good.

I can recommend the SVS. You can buy and try for 45 days and return them for a full refund if you’re not satisfied. Their customer service is excellent. You can get on the phone with someone that will walk you through your setup and answer questions. The app is very easy to use. They do not come in walnut though so that may be a deal breaker. I also have experience with RSL and they are a good deal but no app unfortunately.