@slaw would you recommend springs instead? I'm not willing to drop a lot of coin, so switching to springs seems like something I'd be willing to try. Any recommendations?
Feedback through turntable
My system consists of a McIntosh C2300 preamp, MC452 amp, MCD500 SACD player, VPI Aries 3D with Ortofon Cadenza MC cartridge, Manley ChinookSE phono stage, PS Audio P5, Sonus faber Cremona Auditor M speakers and REL B1 Sub bass system. My issue is with turntable use only; SACD has no issues. On my pre when volume is +55 (peak at 45watts) I start to get feedback through the turntable - a sort of low freq sound, back off volume and it goes away. My Auditor M speaker is about 3 ft away and in front of turntable. I do have a rumble filter (KAB) installed between preamp and phonostage to help with sub woofer pumping. Due to room layout I cannot rearrange the setup/move turntable. My turntable is on a 2.5" block of wood and that sits on 4 isolation blocks via spiked feet. Any thoughts how I can eliminate this problem? Harry Weisfeld with VPI states he has 4 15" woofers (JBL Everest) near his Prime Signature setup with no issues at all. Why am I having this problem and how can I eliminate it? Thank you in advance for all feedback.
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Ah, got it. Right now my rega rests on a wooden plinth that is resting on a partially inflated inner tube on my credenza. Getting rid of rubber would mean I need a new method of vertical seismic isolation for the plinth. Hence my spring inquiry.. Also, my tube pre amp is on a wooden plinth on an inner tube. So I'll need some springs there too.. |
toddverrone, Once you figure out the weight of your Rega and wooden plinth, you'll have another decision to make, IMO. The standard thought would be to go with 4 springs suited to the weight of your equipment. Here's another thought...what about three springs? Depending on the weight, 3 springs will give you a somewhat horizontal isolation effect in addition to the vertical because it won't be as stable as a 4 spring approach. Of coarse you can buy four and try each way. You won't be out much money. Food for thought? Later, you can try cones under your wooden plinth as well/and/or some sort of discs under the springs. I use carbon fiber discs at some locations, dependent upon the final sound. Lots of options. |
Going from 4 springs to 3 springs won’t buy you much. Neither 4 springs nor 3 springs provide much, if any, horizontal isolation since springs are inherently stiff in the lateral direction. There is some isolation in two rotational directions IF the springs are actually matched to the load and the ISO SYSTEM is not too stiff. The ISO SYSTEM resonant frequency will be lower for lower number of springs. All things being equal I usually recommend preloading the springs with mass such as granite or marble, if needed for matching the (relatively light) load to the spring rate of the springs. |
geoffkait, I understand where you're coming from. I know that lead can deaden the sound if not used thoughtfully. I should have then said, the shelf that supports the component I need the additional weight in my system to get the proper loading, I use a BDR shelf that doesn't react to the addition of lead like other materials. I have several weights of brass with points that work well in other areas. My main point was, for a tt, where level is critical, I find in my system, I like to have a support structure that has a built in leveling adjustment. I find if one has a tt with adjustable feet, it's best with them screwed all the way in and do the leveling elsewhere. In some cases where finances are a major factor, this may be a way to go at some later point. Another positive is that you can then play with better (feet options) on your tt that will better address the sound quality while still using the springs under a tt's DIY shelf. Having said that, the addition of marble shelves or any other shelves, while adjusting for load, will not help with the leveling. The bags of lead shot or brass feet strategically placed is an option that can kill two birds with one stone, so to speak. The important thing is to get started and all of the many options available to you will be a good upgrade in the future. |
Springs are self leveling. Absolute level is obtained by slightly moving one or more spring using thumb and forefinger. Obviously the load should be distributed uniformly when level is an issue. Tip: for CD players absolute level of the spinning disc is usually not the same as the level of the top of the chassis. Addendum: I actually like brass just slightly more than I like lead, which I loathe. They both seem like such a good idea, too. Glad to hear you're are able to live with them. 😃 |
(I use these types of things on the platform and not the component itself.) bdp24, You're absolutely correct. Sand is very inexpensive as well! Geoffkait, Thanks for allowing me to explain my process more than I initially did. I have a new DIY wall mount/equipment platform I'm completing in (my mind). I will be ordering more of your springs in order to make it a reality. Happy listening |
lewm, My thoughts exactly. 13blm, Not to get into a debate, but I've heard the difference in my own system of various aftermarket cones, stillpoints etc... Saying they do nothing for isolation is just plain wrong in my experience. Maybe we could get into the symantics of isolation vs. effective ways of dealing with vibrations/resonances but I won't do that. I just report on my experiences. Good luck with your products! |
Coupling a component to a vibrating surface isn’t "isolation". As a turntable manufacturer I have a pretty good idea of what works, however there are many variables and results can be unpredictable. I consider direct coupling methods as "tuning" devices. Isolation devices I feel offer a more accurate window into what the product was designed for. Also my footers are adjustable and can couple or isolate according to customers desires. Any method that increases your listening pleasure is the correct choice! |
Going on the advice of "How to Get Better Sound", I placed my TT platform on the side wall about 3 feet from my left speaker. Because my sound room is on the second floor and I have a suspended floor, I built a suspended platform, out from my wall using appliance springs and tie-down straps/metal cables, so it basically "floats." This worked great, until I added another JL Fathom 13 sub. I couldn’t even turn the subs on, due to low frequency feedback that would build on itself. I tried the inner tube trick, the sandbox trick-everything I could think of to no avail. I finally moved my turntables to between the speakers. I’m sure, some of you are thinking-what a moron-everyone knows that and I would agree. It took me several trial and error positions, to find this place, where no room nodes are effecting the playback. I think in the long run, acoustical energy has a huge effect, on the playback, specially at high volume levels. As far as cones go, I was a skeptic. I have a Theta Miles CD player I dearly love and only use analog outs on it. I had to utilize thick foam, so the low frequency would not effect the playback. (too much low frequency for the room size) I placed four cones, one under each corner of the CD player and was amazed to not have anymore low frequency pick-up. Maybe I will try just three cones in the future. I know you said you can’t move your equipment, but as mentioned above, sometimes just a little change, can have a huge effect on your sound. Room nodes can be neutralized some, with room treatment. As a matter of fact, I think proper room treatment, used in the proper way, will give most of us better sound, than an equipment upgrade. I’m a believer in Dennis Foley’s technique and products. If you haven’t tried them, or are not familiar with them, go to his web sight "Acoustic sounds." |
handymannMay just have something along those lines engraved on my headstone. In my book one of if not the most overlooked things that should be undertaken, the earlier the better. The disadvantage being it lessen's the frequency of changing out gear, tough choice that it is. |
@slaw dude, chill. I’ve had a busy weekend and I just finished installing the springs on Thursday, so I’ve hardly had time to report back. I didn’t realize thread loyalty was a thing. I bought some 2" compression springs with a spring rate of ~9lbs/inch from Grainger. I then drilled 4 holes in the bottom of my maple butcher block platform approximately 3/4" deep and installed the springs in the holes. To protect my furniture, I put cork discs under the springs. I also finished mounting the tt motor on the butcher block. I still had the motor circuit board attached to the tt plinth, which made moving it a pain the ass. So far I like the sound of the butcher block on springs better than on the inner tube. As far as leveling/ mass loading, my butcher block is 2" thick and plenty heavy, especially when the tt is on it. When I drilled the holes for the springs, i made sure they were as equal in đepth as possible. That, combined with the self leveling nature of springs has made leveling a non issue. I also thought of using three springs, but it was too wobbly when I tested it. |
I have moved my speakers and sub (crossed at 49Hz) to the adjacent wall - this has helped. My sub is now approx 15' from TT and furthest speaker cable is 20' from amp. I made some temp cables using 14/4 in-wall cable to try the relocation prior to outlay of a pair of 20' speaker cables. without the REL engaged I can now pump the volume up with no feedback (one of my Sf Cremona Auditor Ms is 5' from TT); once I engage the REL I need to adjust the gain to keep from getting some feedback at louder volumes. So, this does enforce the thought the problem was acoustic and not mechanical. No shared beams between TT rack and REL now. Next, I may try putting the REL on a 3" maple base. Jim Pendleton with Osage Audio has been very helpful and spent many hours helping me tame this wild dog. I will also replace the OEM inserts on my TT feet with the Symposium inserts. Thank you everyone for your suggestions. |
"So far I like the sound of the butcher block on springs better than on the inner tube. As far as leveling/ mass loading, my butcher block is 2" thick and plenty heavy, especially when the tt is on it. When I drilled the holes for the springs, i made sure they were as equal in đepth as possible. That, combined with the self leveling nature of springs has made leveling a non issue. I also thought of using three springs, but it was too wobbly when I tested it." sadly the geometry of inner tubes and air bladders is all wrong. The contact surface area is much too large and the rubber material damps too much, compared to springs. |
Geoff- I will say that I'd try little bowls if there was a believable explanation for how they work and what they do.. I'm not a total reductionist, so I don't shoot things down if they aren't ideas in the mainstream, but my mind does need something to go on, so I can figure out how to implement. Though I suppose it would be pointless since I can't imagine decorating my house with copper bowls.. My lovely wife let's me do what I want with the music room, but she wants input on the rest of the house |
stringreen Marble is awful for a VPI.....it rings like a bell. DO try Bearpaws as I mentioned above. Roller bearings are no good for VPI...it must be anchored to the center of the Earth. Anything that allows motion doesn’t work. ..springs, Gingko balls, etc. I have isolated many VPI turntables on my spring systems, including the new very heavy VPI Flagship turntable (on my new Super Stiff Springs), with great success. By the way, marble as the base under the component on a spring based iso system doesn’t ring. Anyone care to guess why not? The earth is not a stable platform, it is a springy one. |
Listening room is on a second floor; suspended floor. Main floor is a concrete slab. I have done the dance thing around my TT and no problem with noise coming through speakers. If I yell/scream into my cartridge I do hear a sound through the speakers. As mentioned, I have now relocated my speakers to the adjacent walls and the REL to the adjacent wall, too. REL is approx. 16.5' from TT; nearest speaker is 5' from TT. I can play with monitor only with no issue but once I introduce the REL I need to turn gain down to reduce feedback as volume is increased. Crossover is set at 49Hz on REL with 180° phase. |
handymann, Yes, room treatments do wonders in providing excellent bass response while also taming bass room nodes. toddveronne, Sorry. I guess the lack of the OP responding got my juices flowing.. Your thanks to the OP, while relevant, are ultimately misplaced. The thanks for the gain you've achieved through the OP's posting should go to all who have provided the info. Your use of three springs, "too wobbly when I tested it". What/how did this translate into the sound??? miner42, You never responded as to your "audio console". When I read that term, I envision an enclosed structure? Given all of the problems you need to overcome, IMO, having an enclosed audio console in the center of your speakers on a second floor is quite a lot to overcome? I do realize it's not relevant now? Given the changes you've made, I'd say it's time for some quality bass control. I've had great success with the Vicoustic Extreme Bass Panels. "Woofer pumping during tt usage", again a sign of the tt isolation being ineffective. |
"too wobbly"..... I have my 2 tier audio rack that I use for my 50lb. amp and my Hydra, along with my maple platforms, BRD shelves... lots of weight.... between my speakers in my small listening room. My bottom maple platform (3") is coupled to my suspended floor by 3 carpet piercing brass feet screwed directly into this platform. Above it are four SUPER STIFF SPRINGS into another maple platform (1 & 1/2") thick. My rack and components sit on top of this. When I walk by, I can see the whole (thing) move. The components, however, are isolated. The sound I heard after doing this was/is transformative!. Wobbly? It can be a good thing. "too wobbly" doesn't address how this sounded in your set-up. |
13blm, Your post last post should had been your initial post. I totally agree with you here. stringreen, You're coming from this by not considering the suspended floor aspect. From what I've seen on your virtual system page (last time I looked, 3 years ago?) you have a system that doesn't take the challenges the OP faces? |
@slaw.. you're funny, I like how particular you are. Yes, you are right, I do owe you thanks for bringing up the idea of springs. So thanks! Also for the idea of getting rid of rubber. That's where the wooden balls for rega feet idea stemmed from. I ended up doing that well before the springs and forgot that I got the idea from this thread.. I get them mixed up sometimes. So, how does it sound? Here are the changes I've made 'because' of this thread. They may not have been mentioned, but the ideas here got me thinking.. - removed 3/4" teak cutting board on inner tube used as iso platform, replaced with bigger 2" thick maple butcher block on inner tube. Sound became quieter, which, in the past I didn't like. But upon further analysis, the butcher block reduced feedback, which was why it was quieter. Recent upgrades in amps, PCs, SCs and ICs let me hear this difference more clearly. Then I got rid of my rega rubber feet and used wooden balls in their place. I put a small piece of no slip carpet cushion under each ball to stop the turntable from sliding (a problem since my motor sits on the butcher block). This cleared up the sound. Mids and highs had better definition and more separation from each other and the bass. Oddly, this has resulted in a more coherent sense of music. And finally, the springs. I replaced the inner tube with 4 springs from Grainger. They are ~9 lb/in rate. I tried three before I drilled counter sink holes, but the instability of three without being counter sunk led to a wobble that looked like the whole thing would fall over. So I never listened to just 3. Also, if I'd have wanted to go with 3, I'd have needed a higher spring rate, as the 3 were far to compressed. Switching to springs has also improved sound clarity and has mostly led to better bass definition. It's cleaner and tighter. Good stuff! Not suggested here, but removing the tt motor from the plinth and making a mount to put it on the butcher block made a YUGE improvement in sound too. |
toddverrone, Thank you for explaining your current changes. More importantly, how those changes affected your listening experience. This is what (it's) all about. Not (who) provides the info that leads to the changes, it's (the affirmation of the info and how it's affecting the change). I'm glad you are enjoying a positive listening experience based upon the info you received from (all) involved with this thread! Happy listening! |
Here's a pic of the no slip pad.. I would hardly call it a pad.. http://philipbrunner.com/wp-content/uploads/2016/01/Ultra-Non-slip-Rug-Pad-4-x-6-P11996891.jpg |
No issue when sub is out of the picture. I have moved the sub to a location 15' from the TT to a non-corner in the room. At high volume I still get some feedback thru TT but, at a higher volume than before. I have moved my speakers, also, perpendicular to the component rack. My speaker cables are 8m in length now. My next experiment will be putting the sub on a platform. |