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Total bass suck out at 40hz

So I'm a little slow, but it occured to me today to see if there were test tones recordings on Tidal of Qobuz. Yes there are. I have a radio shack SPL meter so I went to work playing them to see what I had in my room. I was shocked to find a total lack of audible bass at 40hz. At first I thought they must have made an error in the recording. Then I went to a different set of test tones and wow same thing. I never dreamed something like that would take place. I have read a lot of discussions about bass peaks and nulls and always thought it would just be slightly less in volume at the null, not completely gone. So Am I imagining this and if not what do I do to remedy it. I am apparently missing a lot of music and never knew it. I am currently listening to my freshly refinished Yamaha NS 1000m speakers(just put them in the system Wednesday after work) with a Modwright KWI 200 integrated amp and a Lumin streamer/dac. I also have stereo Rythmik  F12 subs. Thanks, Allen.
mizike
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tomic601's avatar
tomic601
12,911 posts
 
Try a 30’ Blue Jeans cable - pretty good shields/ quality for not a lot of $$ the RF and other trash in the system will determine if you can get away w 30’
twoleftears's avatar
twoleftears
5,318 posts
 
Are you saying that wherever you're standing or sitting within the room, there's no 40Hz.  Have you tried the subwoofer crawl (Google for details)?
mike_in_nc
1,153 posts
 
A 40 Hz null is typical of a room node, as noted. Here’s what worked in my room, where I use two subs and had a 43 Hz null. I moved the subs, measuring at each position. Putting furniture glides ("supersliders" under the feet helps with moving.) The position where the bass null was minimal put the subs behind the listener, near the rear corners.

I agree with others that a distributed bass array of at least 4 subs is a great solution, but I didn’t have room for that.

I also agree that asymmetrical positioning of the subs can help, but I wanted to keep them symmetrical and running in stereo.

The Allison effect (floor bounce cancellation) was mentioned; my impression is, it is typically higher in frequency (100-300 Hz).

SBIR suckout at 40 Hz might be a factor with speakers 7 ft from a boundary, more so for speakers 7 ft from several boundaries.

Oh, one other thing . . . do the subs have continuously variable phase controls, and have you adjusted them for smoothest FR? That can be an important step in many cases. As can be changing the xover frequency, especially if running the mains full range.

I hope that helps.
mizike OP
107 posts
 
They do have continuously variable phase controls. I;m not sure what to try there, I guess trial and error. I have spent the last hour or so just moving them around randomly and re-testing. I have gotten audible base in the 40hz range but it is still down 13db from the 30hz tone. So do I have a peak or a null? I have 90db at 30hz and 89 at 20. The 30 hz tone is clearly audible the 20 not so much but I can feel it well. Back down to play with the phase control and see what that does. I'll be back up later to see if there are any more suggestions. And thanks to everyone who has tried to help, I really appreciate it, Allen. (AKA Mizike)
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