Mains,
I have received the same excellent results that you have reported using Symposium Super Plus platforms under both my speakers and subs.
Kenny |
This is very interesting, because at louder volumes my new subs will cause oscillation that's from either mechanical and/or aerial feedback. It's been in the back of my mind, because I don't get it at the volume levels that I play music, but still...
I'm getting upgraded feet for my table, that use an internal spring system, so the results may be promising, as I attempt to eliminate this oscillation.
Kenny |
mains -
Thank you for the Townsend recommendation, and I have briefly looked at the isolation products for speakers/subs.
I started a post about stabalizing my rack, because I have it sitting out from my front wall on a bouncy floor. My rack is currently spiked to the wood floor, so I'm considering adding footers under the spikes (Mapleshade Heavy Feet). For example, Herbie has a heavy version of their pucks for this. Once, I pick a solution, so that my rack is at its new height, I will secure the rack to the front wall, so that it is rigid.
I will start with my rack, and then work on the rest. My table is getting an upgrade with the new feet I had mentioned and a better bearing.
Kenny
|
Geoff -
Here's the issue. Eliminating my power amps, so only the sub amps are on, I drop my arm on a stationary LP. As I turn up the volume on either sub, l start to get oscillation through the sub. I do not get oscillation if I do the same with my arm up. If I'm actually playing music, I have to turn the sub amps way up before oscillation, so at my listening levels all is good. Back to just the subs on and the arm down with platter stationary, I placed a half inflated bicycle inner tube under my table after I removed the feet. Repeating the original experiment, the oscillation was far worse. So, I'm not sure if I'm fighting mechanical or aerial feedback?
Kenny |
Yeah, that inner tube was just a test requested by my turntable builder to see what the results would be. The results were not good, and how much to inflate was a guess. I'm having second thoughts if this is truly a mechanical feedback issue, so I'm not going to throw darts at a solution I'm not sure about. For example, the guy who distributes my cartridge had me reverse the phase of the ICs going from my line stage to the sub amps. He thought it was phase doubling. This actually killed the oscillation with the arm down on the stationary platter. However, when I play my turntable with only the subs
running, I still get the oscillation at the lower sub amp volume level. So, part of the problem resolved, but still a mystery to fully resolve. My current MC cartridge, uses a different moving coil method (cross ring), and I'm wondering if this may have something to do with it. My dealer, has sent me another lender cartridge to try in order to find out. My desire to stabilize my rack, is to keep my cartridge safe. Kenny |
Toddverrone,
I am not doubting the benefits of using springs, when applied correctly will provide benefits against mechanical isolation. I had mentioned that I'm getting upgraded feet that are made by my table's manufacturer that are designed with a built in spring system. I am also getting an upgraded bearing, but that's besides the point. My table already sits on a Silent Running Audio isolation platform, and with that in place, knocking on my rack with the table sitting directly on the rack, is louder than with the SRA in place.
My bigger point is that I can eliminate the oscillation just by changing the phase of the subs IC inputs. If my problem was due to vibration from mechanical feedback then when I switch the phase of the outputs to my subs I should continue to have oscillation if the problem is vibration. In fact, the vibration is just as strong regardless of phase.
Kenny |
I have eliminated the oscillation with just the subs on and the arm down and stationary, but if I'm playing music through just the subs, I will get oscillation raising the sub amp volume.
i can play my whole system up to my normal listening levels and with my subs dialed in. The benefits of the subs are big and I have resolved my goal of adding fill-in, so my system sounds better than ever. If I do raise the sub amp volume past a certain level while playing music, the oscillation will kick in. So, I have effectively tamed the oscillation, but even though I don't hear it normally now, I wonder if it isn't affecting my sound in some less than obvious way? I also want to know what's causing it to begin with, as the mechanical feedback theory can be simply defeated by phase reversal.
Kenny |
bdp24 - It makes sense that doubling up on springs would create unstable results. Perhaps, like driving on a washboard surface?
My table is non-suspended and I installed the new spring based feet. I can tell you that my sound is smoother, the background is blacker, and bass is better. However, this did not really do anything for the lurking oscillation that I can reproduce from my subs. My last puzzle piece I will go after is my cartridge. When I get my loaner cartridge to test it may reveal something.
Kenny |
geoffait
The ride would be chaotic and bumpy, but not bumpy like a washboard, bumpy like an aircraft going through heavy turbulence, a series of unpredictable lurches up and down
So, is this why we hear reports of tonearms actually jumping up and down off the record surface?
Kenny |
Thanks, guys. If we can take a brief moment to get away from the springs, my bouncy floor can cause foot falls that can cause my rack to slightly wobble. If I throw a party, forget about it!
Without moving the rack, I want to tie the top rear outside corners of the top shelf to the front wall behind the rack. So, hard maple 2x4" rail across wall directly behind top shelf with maple 1x2" boards connecting the top shelf corners to the rail. BTW, maple because it matches my rack. My isolation/non-isolation question is, should I use any damping material where the 1x2" members are connected to the rail on the wall and top shelf? I was checking out Acoustical Solutions isolation pad that you can cut into individual 2x2" squares. They are a 3/4" sandwich of rubber- cork-rubber.
The more general question is, do I want to limit vibrations from the wall coming into the rack due to the direct connection, or do I want to isolate those vibrations? I have heard both opinions.
Kenny |
Thanks, toddveronne. The title of this post included general isolation, so why I threw my rack into the mix.
The wall is a bearing wall that sits on the foundation wall, so it's not wiggly! The rack can only rock forwards and backwards, so much more stable side-to-side. If I stomp/jump in front of it, I can get the stylus to skip. Otherwise, not a problem, so it's a safety issue.
The 1x2" pieces will be rigid if I directly tie them into the 2x4" rail across the wall. Another A-gon member recommended this over dampening material in-between, but my dealer suggested the dampening. The positioning of the 2x4" changes if I use/don't use the dampening, so I'm trying to avoid a re-do. When playing music, if I put my hand on the wall, I can feel the vibrations, so do I want the vibrations transferring to my rack or not is the question? It seems, that a small consensus so far supports the direct approach, and to solve vibration issues by isolating the components, instead.
Kenny |
Geoffkait
This of course means that in order to escape at least some of the seismic type vibration one needs to decouple from the physical surroundings entirely, including walls. Furthermore the effects of seismic type vibration don’t necessarily manifest themselves overtly, e.g., needle jumping from the groove, it can be more subtle and insidious. You don’t know what you got til it’s gone, like the song says.
I wonder if if the recording studios account for seismic activity!?
I'm going to stabilize my rack and isolate my gear.
Kenny |
Mains,
After, I stabilize my rack, I think my best approach is to isolate my speakers and especially my subs in the beginning. Then, go ahead and better isolate my equipment.
I had checked out the Townsend website due to this post, and sent an email seeking equipment recommendations. I'm waiting to hear back. Checking out the products, I can't use the podiums due to proximity of other equipment, but the Bars would work for my subs. An additional thought would be to put the Bars under my existing Symposium isolation platforms that the subs currently sit on. From your experience with the product, do you think this application of the Bars would be my best starting point?
BTW - I will be adding to my rack, side boards at the rear with a 1" dowel running across the backside of the rack at the top. From the dowel will hang strings attached to my components' ICs and power cords for the purpose of relieving strain due to the weight of these cables on the connectors. This was recommended to me by Bill at Shun Mook, and the side boards will also help to make my rack more rigid.
Kenny |
Okay, everyone. Back to real world results, because that's what counts, right?
John, Geoff - Thanks, for chiming in on my rack stabilization post and pointing me to floating isolation. In particuar, the Townshend isolation products.
My isolation bars for my subs arrived yesterday late afternoon, and I quickly set them up under my subs. This is not a review, but just an initial statement and observation. Experimentation and serious listening to follow.
For all you vinyl guys out there with subs, these isolation bars completely cured my oscillation problem caused by mechanical feedback through my floor from my subs, and up through my rack to my turntable. I can turn the sub amps up full volume and kill the rumble filter, and no oscillation. Problem solved. My hat is off to the folks at Townshend Audio.
What I have initially observed regarding sound, is that some level of distortion has vanished, revealing the resolution already inherent in my system. Clarity. It's now become perfectly obvious to me, that proper power management and isolation in the beginning, will reveal truthfully how one's system can sound. Too bad, my approach came ass- backwards, but now I can do better.
Kenny
|
Bob (gdnrbob) - I didn't want to miss thanking you for your Townshend recommendations as well!
Kenny |
Bdp24,
I'm not sure about my main speakers for the Bars, because I have no room to the side of the speakers for an extended pod. And, both of my speakers are bordering walkways. When I first placed the subs on the Bars, and I wobbled them around on the Bars like jello. I thought this was hilarious at the moment!!! A sub weighs 118 lbs without the Symposium platform, so it wiggling around as I pushed lightly was weird, indeed! I could not possibly have my main speakers in the way of dogs, kids, and the wife like that. - LOL
Instead, I'm seeing my next step, besides stabilizing my rack, to add isolation to my amps. Any suggestions, including pods and besides the pods? See my system pic for advice.
Kenny
|
Eric,
I have been conjuring up a number of solutions for my mono blocks that may include the isolation pods underneath. What my dealer sometimes uses at shows, is Shun Mook diamond resonators below, mpingo discs on top of transformers, and the tube resonators. I like the Shun Mook stuff, and have heard a buddy's system incorporating an assault of their products. These really helped to bring out the most of his system and really fine-tuned the room. Many, think this stuff is weird, yours truly as well, but it works. Albeit, there's a price to pay for it. In my situation, I'm now contemplating between the pods or resonators under my amps.
Thanks, for the recommendation of the Iso-Pucks, I'll check them out as well as the other products.
I have to stop buying tweaks after isolating my amps, because I have to purchase a new line stage as this is a needed final component for my current system.
Kenny
|
Todd,
I checked out Eric's information about the IsoAcoustics Gaia feet that provide lateral isolation for speakers. I already use Symposium platforms under my speakers and they were a big improvement to the stock spikes and Herbie's discs that I previously used. I'm not sure if this is the time to throw more money at something without more knowledge.
Eric - Do you know if the Gaia feet are a solid footing for speakers, so no wobble like the Townshend pods? I could not determine this from their website info.
Kenny
|
Thanks, John.
This is great information, but unfortunately I cannot use the seismic bars for isolation under my speakers. Only, a solution directly beneath and not protruding beyond the footprint of my speakers can be applied. And, that's one reason why I have the Symposium platforms. I think I will leave my speakers alone for now, because my system right now sounds pretty killer.
Now, that I have solved my sub-to-turntable oscillation problem, I am enjoying the extra benefits of SQ from the isolation bars, so thanks John.
I'm going to do some serious listening.
Kenny |
John,
As I mentioned before, I have no room for the bars with the pods extending out past the footprint of my speakers. However, this sounds like good information for others who have greater flexibility in their setup.
Kenny
|
Eric, I could if I moved my large rug back away from the front of my speakers, but the bars still cause the wobble effect that I'm trying to avoid with my speakers in the walkways. Regarding your VPI, I believe with their HW-19 Jr. model they used sorbothane instead of springs? Kenny |
All, Looks like I'm fortunate to have missed the posts that were removed. We may be confusing genuine enthusiasm, which we all seem to share here for this hobby, for something else. Eric, surely demonstrated that in spades when he pointed me towards my subs. When John, Geoff, and others pointed me towards the isolation devices. The end results of this enthusiasm, truly solved my problems and improved my SQ. I am under the impression that John is not really "selling" anything, but is actually helping us to procure products that he believes in, and truly enthusiastic about. And, he happens to know the Townshend folks very well. This is my sense of it, as he helped me to procure my isolation bars. Kenny |
Playpen,
Interesting. Can you provide a picture for a better visual of what you've done?
Kenny |
Playpen,
I too did not have that picture of your dampening solution in my head. The cabinets produce their own sound into the mix by resonating, so it looks like you are dampening this by fine tuning the locations that will give you the best sound?
For my DIY subs with the Isolation Bars, they come with an add-in dampening material called NoRez. It comes in sheets that you cut to size, and that I will add to the inside walls of my subs. The NoRez is backed by a very strong adhesive, so it's a one shot deal when applying. I'm hoping that I will like the sound more after I install it.
Kenny |
