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subwoofer with zero punch... help

I'm a noob go easy but give me the technicals(if any) because I want to learn. I was very excited to get that extra grunt and some good punch from kick drums out of my new subwoofer when it arrived.  I was severely disappointed when I plugged it in.  It only sounds bloated and boomy and there is ZERO amount of punch or slam to speak of.  And I do mean zero! I've had 6in car speakers that "hit" harder than this thing.  It'll shake everything like crazy but there is no definition to any of it. I need help diagnosing where my issue is because I don't think its the sub itself. lol

Sub: SVS SB-4000
Speakers: Klipsch RP-600M (these sounded great on their own)
Amp: ~90s JVC 70w/channel home theater amp 
input: ~$100 headphone DAC and playback from TIDAL
Room: concrete floor basement 26ft x 14ft x 7ft drop ceiling with R19 in the floor joists, full cover thin carpet, lots of furniture and a decent amount of cheap sound absorption foam. 

Other Notes about setup:
1.Sub signal is RCA out of headphone jack, I know its not ideal but splitting rca out of my DAC was worse
2.This is temporary residence, I plan to move but I want to know what my problem is before I bring my issues with me to a new listening space. 
3. The acoustic foam was an attempt to kill the drone from a crypto mining rig which it was successful in accomplishing.

What I tried so far: Tuned the eq for the sub with a tone generator. Found that 65hz was nearly silent, I boosted that and bumped the LPF to 75hz (12db slope). I also tried various boosts and cuts between 65 and 140hz on the whole system but everything sounded worse.  For reference I have 4in woofer monitors at my desk with a little Polk 8 in woofer and it "punches" harder than the SVS 4000.  Like the title says.... Help...
ctstauffer
terry9
2,348 posts
 
The science was done at the University of Salford, School of Acoustics. The noted Cox teaches and researches there. Spoiler alert: it's not snake oil, like most of what you read.

Mechanics of build is available in several places. Absolute Sound (IIRC) about two years ago, and manufacturer's websites are good. Go for the real goods from industrial suppliers like Pabco, which IIRC, manufactures Quietrock. I use Quietrock 545, and recommend it enthusiastically. Great company too. 
terry9
2,348 posts
 
Should have mentioned elastomeric glue and caulk. Chemlink makes great products, I used 10-15 cases of the stuff.
terry9
2,348 posts
 
For amps, I build my own for the most part. But when I want clean, good sounding, bullet proof power at a reasonable cost, I always use Bryston.

Check out their factory rebuilds by calling them. I emailed them about a month ago on Sunday. The VP responded Monday morning. I phoned him that same morning.Then I bought a factory reconditioned unit that afternoon, with an additional 5 YEAR WARRANTEE. At a reasonable price.
Post removed 
auxinput
2,920 posts
 
Two things jumped out at me:

First:
Found that 65hz was nearly silent
This is clearly a bass NULL or bass node due to the size of your room.

Second:
The LDF drop ceiling and R19 is creating an enormous bass trap that is sucking the life out of the woofer.
Bass traps do not work like this.  Bass traps DO NOT suck the life out of the woofer.

You can over-deaden a room with too much acoustic treatment, but this is mostly with the midrange and high frequencies.  It's very easy to put too much acoustic absorption into a room and this will definitely suck the life/excitement out of the room.  But once again, this has to do with high frequencies.

If you look at the exact size of the room ( 26X14 with a 7 foot ceiling), Amroc shows a primary bass node right at 65 Hz:

https://amcoustics.com/tools/amroc?l=26&w=14&h=7&ft=true&r60=0.6

I have really bad bass nulls in my own room and the only thing that I found that really affected this was tuned membrane bass traps.  If you want to treat the room that you are in, I would start stacking tuned membrane bass traps in the rear corners.  GIK Acoustics makes their Scopus tuned membrane bass traps.  They have a T70 that you can just buy online at $199, or you can call them and have them custom make a T65 (they will custom make for any frequency).  The cost will not really be any different.
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