I am doing some research about the need for a product I think bassists and guitarists might find useful.  I want to start by reading some chats that 4 and 6 stringers have.  I know about TalkBass and, of course, the Alembic club.  What other ones do you know about?
Thank you in advance,
Rich

Rich, this place is all I use for my lowend needs. 

Not that you asked but it might be interesting to hear others 'favorites':

I have four frequently visited sites; Alembic, XJBikes, Leyland Tractor BB and Weather Underground.

Alembic because it is cool and the community is great.
XJBikes because I have an old Yamaha and no one else is going to maintain it, another great community (a little rough around the edges at times) it has made me a decent motorcycle mechanic.
Leyland same as above, I have an early 70's tractor and I need to keep her running, mostly UK members, super helpful, super nice and superior skill AND tools over what I have.
Weather - Even though I can't control her sometimes I like to know what Ma Nature has planned.

mylespaul.com
epiphonetalk.com
acousticguitartalk.com

On a daily basis, these:Alembic Club
Komodo Kamado Forum
Steve Hoffman Music Forums
Audio Aficionado
VPI Forum


Less than daily:
AudiogoN
AudioKarma

I only ever post here at the Alembic Club and on TalkBass, using the same handle.

In addition to that, I regularly read Bluegrass Today, Mandolin Café, The Un-Official Martin Guitar Forum, and less often (like weekly) Banjo Hangout.

This is the Australian equivalent to talkbass;

http://www.ozbassforum.com/

And the Uk version.. http://basschat.co.uk/

Graeme

There are a couple of facegroups that I participate in. Mainly the Alembic ones.
https://www.facebook.com/groups/alembicbass/

https://www.facebook.com/groups/131120133706251/

The Les Paul Forum
RU Kind
Fractal Forum

The Gear Page http://www.thegearpage.net/board/index.php

Alembic, and sometimes the Steel Guitar Forum and Talkbass.

R.

Gearslutz! It's a great place for audio engineers, although in the last few years, it's been inundated with more newbies and fewer of the big legends.

https://www.gearslutz.com/board/

Thank you, everybody who provided some info here.  I appreciate the help.
Rich