If your current setup (preamp/receiver) has an "infrasonic" filter, it is the same thing.
I'm guessing the turntable is a direct drive? Usually direct drive turntables aren't as isolated from the base as they could be..... Subsonic/infrasonic filters work well with them. Beware of any "in line" subsonic filters unless they are designed specifically for the phono stage....
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Hi Paul
I just added a Clearaudio Ovation to my system this week and I to am having some feed back issues. Needless to say I am very disappointed, but it is what it is. Mine seems to be feeding back approximately at 30hz and 120hz at volumes ranging from 85 to 95 db.
Some of the contributing factors that I think are helping cause my issue is my listening room is very small at 14 x 10 x 9, located on the second floor of a 122 year old house and I have the turntable sitting on a very cheap fiberboard end table along an outside wall about 3' feet in front of my left sub.
I placed some anti vibration pads under the feet of the turntable (available from amazon for about $10 to $15 for a four pack) which helped reduce if not eliminate the feedback at 30hz and added a little more detail to the recording. I use an active crossover to integrate my subs that has a digital graphic eq built into the inputs that I used to reduce the 120hz output of my system thus eliminating the feedback.
My next move is to build a prototype table out of 2 x 4 pine so I can relocate the turntable so it is above and slightly to the rear and left of the sub. If this works I will then have Saluda River Audio Stands build me a permanent table out of maple and walnut.
Also when you said that all hell broke loose when you switched polarity on your sub I believe that was when your subs were actually in phase, at least with the turntable.
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What kind of sub ,or how cheap is it made.
Buy the svs sb 3000 with control app for under $1k delivered
And free shipping and 60 day audition nothing better even at $1500 plenty of awards !! |
It is s Must ,saying what brand,and model it is cheaper ones
Has minimal control small amplifiers, magnets and pole pieces
As well as cabinet construction all important factors
How to you adjust it ? The SVS 3000 line SB with app
For just UNDER$1K 13 inch aluminium driver beat my $1500 JL Audio in every respect
The split coil poll piece works for great bass even at low volume
And the app works great . #1 sub and buy of the year. |
He already told us what brand and model the subwoofer is, a REL T9i. |
Buy the svs sb 3000 with control app for under $1k delivered
Buying a bigger and more powerful sub is not going to fix a turntable problem. |
for better of for worse I use EQ on my power amp (crown xti) to make a high pass filter that slopes steep below 30Hz, this removes any subsonics from record warps. If I place the needle down on the record you see the cone bounce without the filter, you see almost no movement with the filter engaged, I find it very reassuring especially as it should prevent any feedback. It may be a band aid to an underlying issue but It does work. |
@paulgardner:
I had the rumble problem for quite a while. I built a suspended TT platform that is isolated from the floor and walls, using dampened springs. I also recently purchased a DBX Venue Driverack 360. I haven’t had a problem since. It incorporates a graphic, as well as a parametric EQ, with “Q” adjustments that come in very handy. The “360” has many other features that I enjoy. You can control the unit with a smartphone or laptop. ALL speaker’s phase can be adjusted from your chair, as well as ALL speaker’s timing. Of course each speaker has it’s own level control and shelf roll offs. I can even use it’s subharmonic synthesizer for deep bass, although sparingly. If you’re not familiar with this unit, it would be wise to check it out.
(I’m using two JL Fathom 113’s as subs, with my TT platform on the left side wall). Placing your TT in between or in back of your speakers will exasperate the problem even more. |
I had the EXACT same problem. Get some long cables, move the table, it'll fix it immediately. My subs were on isolation platforms, turntable on a wall shelf with a symposium ultra under it. I even borrowed other tables, nothing. The turntable was in a room node and no matter what I did, nothing worked. I moved it, never had another issue.
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I’ve solved that feedback problem on many turntables by dampening the plinth. |
Try a different phono preamp. I had the exact same problem and spent two years and a lot of money trying to solve it. I relayed my story to a well known vinyl writer and he suggested I swap out phono preamps. I was surprised when a friend brought a spare unit over and we hooked it up and the rumble/feedback immediately went away. My preamp was later bench tested and measured perfectly, it just didn’t play well with my setup and stereo subs. Good luck! |
Interesting. I’ve been considering upgrading my phono stage anyway. Maybe this is the excuse I need to pull the trigger. Thanks. |
Subsonic rumble filter! All better! I understand it’s a “bandaid” approach but it totally worked and my stereo sounds amazing again! YES!!! Thanks again everyone! |
Wow! This sounds like what happened to me few weeks ago when I moved my equipment around, the higher the volume goes the more rumbles the sub makes. The Preamp and the Phono-Stage Preamp originally were in the same cabinet, w/i 3' from each other. The problem happened after I moved them apart almost 3 times of that distance. I believed the fix was moving both equipment back in the original position. You might also want to look into the cable orientation relative to each other, like power cables and interconnects should be crossed instead of parallel. Good luck in your troubleshooting. |
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Glad to hear you got it worked out and thanks for sharing the solution. |
Subsonic rumble filter! All better! I understand it’s a “bandaid” approach but it totally worked and my stereo sounds amazing again! YES!!! Thanks again everyone! Yes until you figure out how to stop the airborn feedback, it is a band aid, as it’s taking away what stereo info there is below 140hz Quote: "The circuit "monos" the low frequencies below 140 Hz" I still don’t understand how this will fix the airborn feedback test I asked you to do though, did you try it again with this filter in place? Cheers George |
Yeah I hear ya. I also built an isolation platform out of two butcher blocks. I sandwiched it with gel furniture pad discs. I wonder if that is contributing to the solution more then the rumble filter. I’ll remove the filter when I get home and give it a shot. |
George - so I removed the filter and the rumble returned ☹️ even with the homemade iso platform. So even if I’m missing out on super low frequencies, it’s better than the earthquake situation. I’m planning on upgrading my phono pre so we’ll see if that does anything to alleviate the rumble like one guy said earlier. Thx! |
Yeah unfortunately you have to live with the negatives of the rumble filter is doing to the low bass, shame as that was what getting a sub woofer was all about.
Like I said the only way to totally get rid of "airborn feedback" as you found you have with the way I said to test for it, is to have the TT in another room as I did and which worked a treat, best bass ever, as my 2 x Kef B1814’s in 2 11cu ft enclosures were tuned down to 19hz fs each.
Cheers George |
The airborne feedback is not the issue, it’s the structureborne feedback. That’s what the fuss over isolation is all about. Wake up and smell the coffee! ☕️
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He's already proved he has air-born feedback, do the test above as in my first post, the way Ivor Tiefenbrun laid out all those many years ago,
(know who he is?) Or sell the OP your useless car valve springs, or your magic pebbles, better still give them to him as they will end up in the bin, even better still give something constructive to these forums, instead of your constant malignant voodoo talk.
http://www.machinadynamica.com/machina31.htm
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Surely you must believe most other people are as backward and incapable of real progress as you. I’m considering putting you on the payroll nevertheless in view of your excellent job of getting the word out. |
LOL you guys are funny. There’s gotta be a solution that doesn’t involve moving my tt to another room. Would a different tone arm help? One that doesn’t use magnetic stabilizing? Ugh this is no fun. So strange that it developed over time too. I’ve had this set up for about a year now and it just started a month ago. I did have woofer pumping issues with my mains at first but fixed it by putting them on stands vs. the same surface at the tt. Do you think going to the Herron phono pre will help at all? |
Back in the TT days Paul you had speakers that were lucky to go below -3db@50hz, now there’s subs that can go 2 octaves lower, with 1000w plate amps, this is what I found with Linn LP12/Ittok/Supex1000 and my Kef B1814’s 19hz, then CD came along, and then no problems.
Cheers George |
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No not telling you to, would never do that Paul, but beside putting the TT in another room, it was the only other fix for me with bass that goes to very low frequencies.
Just dawn on me, if you have any tubes in the chain, these can go "microphonic" some call it "euphonic" (w**k w**k) and this can cause runway bass oscillation also.
If you have then do the finger nail light tap test on these just like the plinth test, but without the stylus on the record this time.
Cheers George
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Ok I’ll try that test and report back. Thx |
years ago I lost a bass unit on a rega jura. The combination of TT, room, track and record warps led to a loop that saw the drivers very quickly oscillate more and more until the paper cone literally tore open around the center area, this took less time than I could get over and turn the volume down....the other driver survived the experience, I don’t think the voice coil burnt out but somehow the extreme excursion caused the cone to rip. |
Hey George - tubes seem to be ok. I’m running the Phonomena II through the aux so I’m assuming the preamp tube(s) in the amp aren’t being utilized, right? |
Where and in what are these tubes situated, if in a tube preamp (model?) and your using the aux input you are still fully using the output buffer tubes of the preamp, but you say they seem to be ok?
So then I'm affraid we come back to the air-born feedback.
Cheers George |
big_katydid
The combination of TT, room, track and record warps led to a loop that saw the drivers very quickly oscillate more and more until the paper cone literally tore open around the center area, this took less time than I could get over and turn the volume down
Yes, this is another way the air-born runaway feedback oscillation can start. The wrap was the initializer, then the air-born takes over and just runs away getting louder and louder till something goes bang! Cheers George |
The tubes I checked are in the CM II integrated. 4 power tubes, 3 12AU7s and 2 12AX7s. I’m running the Phonomena II+ phono pre which is solid state. I assume some of the small tubes in the CM II are still being utilized in the signal path - I believe the center position 12AU7 is the Preamp tube. |
Just did a quick test just for fun and placed a pillow under my turntable and the rumble is gone! Super tight bass! So maybe it’s not actually airborne?? Just need some extreme isolation? Hmmmmm interesting |
Almost certainly one or two of the 12au7's will be the pre stage output tubes.
Cheers George |
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what I notice on this topic is that when listening to recordings posted on youtube if the track is from vinyl you can often tell as there is obvious woofer pumping, I assumed wrongly that a signel might have been high passed to get rid of some very low frequency hash, apparently not. Many dance/electronic 12 inches not available on digital format have been uploaded and show this. |
I’m having the same problem. I have a Technics 1200 M3D and KEF LS50s. No issues. I just added a REL T7i and have the runaway feedback rumble at high volume. I added Isonoe footers to the table which didn’t do much. Unfortunately the table and speakers sit on a big media cabinet from Design Within Reach which is not ideal. Not sure what the right next move is. More table isolation, put footers under the cabinet legs, new turntable, new furniture, or new house?
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I'm having the same problem. A simple experiment demonstrates that it is not "air feedback" - but vibrations through the floor/room. I simply put the needle on the record and increase the gain until I start getting the feedback. If I lift the subwoofer, the feedback stops as soon as it is decoupled from the floor. Any other recommendations for subwoofer isolation tweaks? I will look at the iso-pucks. Note that the second subwoofer (across the room) does not create any feedback and I assume that is due to positioning in the room. I have an old house (230+) and the floors are original. |
