Hey folks, resonance issues seem to be on most people's minds when it comes to fine tuning a turntable's sound, and most of the discussions center on numbers. I'm not a big numbers guy, but I do have the luxury of having several cool tables and many cool cartridges, and seem to spend half my life ABing stuff, to get the best sound possible. I have recently progressed in my numbers appreciation to compliance, tonearm mass/cart compatibility. Anyway, can't really find much on what unacceptable resonance sounds like. Would appreciate descriptions of that, so I can add another element to comparing different carts and different cart/tonearm combos. Any opinions appreciated
What does bad turntable resonance sound like?
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tnsilver
Stereo Puppy
worst case scenario and real obvious is a tap dancing tonearm right at the lead in groove. This has a very visual and audible effect but fortunately it is quite rare and when it occurs it's usually a case of excess lack of VTF on top of cart/TA mismatch.
The most wide manifestation of resonance effect on playback isn't audible and is not visual at the tonearm end - but can be observed very clearly when the speaker woofers violently extrude and retract without making a sound. This is known as "sub-sonics". The woofers are responding to frequencies generated by the stylus that are bellow the human audible range. It's twice as bad b/c it not only implies the analog playback system is operating under specs, those low frequencies are very energetic and require the amplifier to allocate much of it's energy to produce sound waves that we can't hear. "sub-sonics" are not necessarily a cart/TA mismatch but are definitely caused by airborne resonances - often on account of speaker/turntable proximity and/or feedback.
In between those two phenomenons is a wide range of effects that resonances induce on an analog playback system. Most are easier noticeable on the bass response and manifest as murky or boomy lows, but are not restricted to that. A cart/tonearm mismatch that is less than obvious typically manifests as dissatisfaction, imbalance and ear fatigue - all results of under-performance.
The most wide manifestation of resonance effect on playback isn't audible and is not visual at the tonearm end - but can be observed very clearly when the speaker woofers violently extrude and retract without making a sound. This is known as "sub-sonics". The woofers are responding to frequencies generated by the stylus that are bellow the human audible range. It's twice as bad b/c it not only implies the analog playback system is operating under specs, those low frequencies are very energetic and require the amplifier to allocate much of it's energy to produce sound waves that we can't hear. "sub-sonics" are not necessarily a cart/TA mismatch but are definitely caused by airborne resonances - often on account of speaker/turntable proximity and/or feedback.
In between those two phenomenons is a wide range of effects that resonances induce on an analog playback system. Most are easier noticeable on the bass response and manifest as murky or boomy lows, but are not restricted to that. A cart/tonearm mismatch that is less than obvious typically manifests as dissatisfaction, imbalance and ear fatigue - all results of under-performance.
This thread has me thinking, and since I'm not a TT expert this could be total BS. But you can calculate resonance modes (frequencies) of a room by looking at its dimensions - in fact there are online calculators that will give you all the bass frequencies to look out for, by just inputting the room dimensions. Is there anything similar for a TT? Probably not, as they are a complex system of moving parts and mechanical springs. If there was a way to put a frequency sweep into the TT, such as from a speaker driver underneath, and then measure the sound level - such as, with a microphone attached to the platter - that should give you an indication of resonant frequencies. Would this provide any useful information as far as how to improve the TT?
Just a wild hare, it may be completely silly.
Just a wild hare, it may be completely silly.
I'd honestly be interested in hearing what a bad cart/tonearm mismatch sounds like. I've been through plenty of tonearms and plenty of carts, but I think the only pairing I ever outright hated was an AT-VM95E on a Dual 1009. Mistracked like a mofo, but that could easily have just been because of the short stubby tonearm with no means of adjusting the overhang. I've heard carts that sounded muddled and confused, but I'd sooner chalk them up to bad styli, crap tonearms, improper loading, or just not liking their tone rather than some mythical match-made-in-heaven scenario. Could also just be something like an aesthetic/performance mismatch (no one in their right mind would put a Koetsu on a Garrard SL65B, now would they?), or just not feeling the music.
That being said, some carts and arms did seem more prone to skipping during footfalls than others, but I feel like you should address the isolation/suspension of the table before blaming the cartridge. And there was this one time when I fixed up a Sony PS-T2 turntable for a friend, mounted an AT95 on the thing, and was VERY impressed at the bass it was kicking out. But maybe that Sony's just an ass-kicker?
That being said, some carts and arms did seem more prone to skipping during footfalls than others, but I feel like you should address the isolation/suspension of the table before blaming the cartridge. And there was this one time when I fixed up a Sony PS-T2 turntable for a friend, mounted an AT95 on the thing, and was VERY impressed at the bass it was kicking out. But maybe that Sony's just an ass-kicker?
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patient_ot
Super Member
I can tell you what a too high compliance cart sounds like on an arm that is a bit too heavy. Muddy, bloated bass and less than ideal tracking. Not recommended.
It's worth taking a few minutes and making sure you're not going down the road of a bad mismatch.
Where things get murky is with Japanese 100hz cart specs, which cannot be accurately converted to Western specs IME. You need to find people who've measured resonance on a tonearm of known effective mass with those, or a third party bench test that did that or measured compliance per Western spec.
It's worth taking a few minutes and making sure you're not going down the road of a bad mismatch.
Where things get murky is with Japanese 100hz cart specs, which cannot be accurately converted to Western specs IME. You need to find people who've measured resonance on a tonearm of known effective mass with those, or a third party bench test that did that or measured compliance per Western spec.
patient_ot
Super Member
The AT is a medium compliance cartridge, not recommended for lightweight Dual tonearms...no overhang adjustment could certainly be a problem...does that model not have the "sled" style adjustment that other Dual automatics have?
It was the original 1009 from 1963, which had a different (and chunkier) sled than the later 1009's and 1019's. Probably a bit massier than the later arms, too.
FWIW, my 1019 came with an Ortofon OM10 when I got it, and I've tried a Grado F3+ and an AT3600 in it with good results. I might purchase an additional headshell and an alignment jig (since proper overhang seems to be a surprisingly well-kept secret on such a popular turntable) to better see which one sounds best. I remember reading iffy things about the OM10 on the 1019, but the OM10 (with a new stylus) sounds wonderful on my primary turntable, a Pioneer L1000 linear tracker. Cleaner and sweeter than my VM95E, but that cart's no slouch either. I'm not sure if it's a better match to my tonearm, but it's certainly a better match to my ears, and that's what matters.
Multiplex
Appease my earhole.
As others mentioned, minor mismatches may result in a bit of a bloated or dense sound in some cases, and thin harsher sound in others. In more severe cases, IGD and sibilance will worsen. In a worse match yet, you can sometimes see dance at the stylus. This will usually be accompanied by woofer pumping, which can cause a weird phase-y modulated sound, particularly in two-way speaker systems. At the same time, long sustained notes from a piano or synth may have a slight quiver of vibrato to them that isn't natural. Crackles, fizz and all out distortion may accompany these symptoms. At worst, the stylus might want to jump right out of the groove at the smallest warp or scratch.
Shure's Era IV "An Audio Obstacle Course" test record has some good resonance test tracks that allow you to hear how a cartridge sounds when trying to track while being excited at it's resonant frequency.
(I was hoping to find a YouTube video of someone using this record, but I wasn't able to.)
Shure's Era IV "An Audio Obstacle Course" test record has some good resonance test tracks that allow you to hear how a cartridge sounds when trying to track while being excited at it's resonant frequency.
(I was hoping to find a YouTube video of someone using this record, but I wasn't able to.)
patient_ot
Super Member
That is exactly what you don't want! You can check the resonance of your cart/arm combo with a test record that has vertical and horizontal resonance tests or a record of actual music. Record the output at the phono pre or rec outs into a computer, using an audio interface or sound card. Then take the file, and pop in into Audacity or a similar program and look at the analysis graphs. Usually the RF will stick out quite clearly in an audio analyzer program.
sqlsavior
Lunatic Member
It depends on what's resonating. A subwoofer calibration sweep on my system seemingly revealed a buzz for every frequency, when done at high volume. Various faces of wooden furniture, cupboard doors, knick-knacks, pictures on walls. My Klipschorn copies could rattle everything in the house, when bi-amped with two G.A.S. Grandson of Ampzilla amplifiers.
But turntable resonances? Unless you're talking about feedback/howling, these are not so obvious. Subtle decreases in clarity, from tiny vibrations adding noise to the signal, don't usually have a recognizable sound to them, IME. They just make the difference between hearing some detail or characteristic, and not hearing it.
But turntable resonances? Unless you're talking about feedback/howling, these are not so obvious. Subtle decreases in clarity, from tiny vibrations adding noise to the signal, don't usually have a recognizable sound to them, IME. They just make the difference between hearing some detail or characteristic, and not hearing it.
Multiplex
Appease my earhole.
Indeed, plinth and feedback resonances are a different story than tonearm compliance mismatch, yet can make every bit as much difference.
My old Denon DP-33F used to start to sound vague and hollow as I turned up the volume. I tried AT isolation feet to reduce this. That really didn't help. I eventually discovered that the offending resonance was actually that of the acrylic lid! If I put the lid down, it sounded hollow. If I put it up, it sounded great! (Lid off was best, but removing it and replacing it after every play was not an option.) So, I've gotten into the habit of playing lid-up ever since, even though it doesn't seem to make much of a diff on my Technics TTs.
My old Denon DP-33F used to start to sound vague and hollow as I turned up the volume. I tried AT isolation feet to reduce this. That really didn't help. I eventually discovered that the offending resonance was actually that of the acrylic lid! If I put the lid down, it sounded hollow. If I put it up, it sounded great! (Lid off was best, but removing it and replacing it after every play was not an option.) So, I've gotten into the habit of playing lid-up ever since, even though it doesn't seem to make much of a diff on my Technics TTs.
Thanks all for the input. Seems if your table is sounding crappy, for some reason 'resonance' issues are on the list of things to investigate along with a hundred other things.
Could folks comment on the percentage of things that can negatively affect turntable sound caused by resonance issues and Multiplex, is there a way to tell the difference between, plinth, feedback and compliance resonance issues, just by the way the music sounds. One other thing. I have put together many systems with turntables, and find that 90% require some kind of low filter, to prevent what looks to me like excessive woofer excursion. Is this the experience of others, or is their something I should be doing differently that will allow me to forego the use of a rumble filter.
Could folks comment on the percentage of things that can negatively affect turntable sound caused by resonance issues and Multiplex, is there a way to tell the difference between, plinth, feedback and compliance resonance issues, just by the way the music sounds. One other thing. I have put together many systems with turntables, and find that 90% require some kind of low filter, to prevent what looks to me like excessive woofer excursion. Is this the experience of others, or is their something I should be doing differently that will allow me to forego the use of a rumble filter.
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Multiplex
Appease my earhole.
It's pretty hard to say what percentages of something will lead to a given result in vinyl playback... But resonances are everything. A turntable simply is a mechanical playback device. It is trying to make an exact electrical representation of a physical waveform cut into a vinyl medium. Any excess energies or "shortcuts" resulting in exaggerated, or incomplete waveforms is incorrect, as is the introduction of harmonic distortion, or other additional waveforms. There are countless combinations of gear that may interact in any given way, and a plethora of environmental issues can affect things.
But here are some things to try...
If you play a quiet passage on a record, you can often times tell quite a bit by tapping your finger on the plinth. (If your TT is suspended, you won't want to try this on the suspended portion. It will likely bounce your stylus right out of the groove.) To hear a dull thud is pretty normal. A loud hollow bonk is not so good. This means the plinth is resonant and will likely become microphonic at higher volumes. Also, tap the cover, if your TT has one. If it has a loud bonk, it too can be microphonic. Usually the better the turntable, the less issues it will have of this nature.
Next, try tapping on the shelf/stand that the TT is on. Quiet is good. Dead quiet is best. This means your TT has good isolation. If you can hear an obvious thud, isolation is not so good, and any resonances of the shelf/stand under the TT will end up in your audio.
You can also check for feedback by cranking up the volume. You'll hear the tone of the turntable change as the volume level increases, if you are having issues with feedback. You may even get a howling tone or woofer oscillation from that loop. (Watch your woofer cones as you turn up the volume. Be prepared to turn the volume down quickly. Too much feedback can damage speakers.) Moving the TT away from the speakers, using isolation feet, or a wall mounted shelf can help if you have these issues.
A test record that demonstrates resonant frequency is probably the best way to be sure that your cartridge, headshell, and tonearm are all working together nicely.
Often, these issues are intertwined. Feedback and footfalls can exacerbate tonearm compliance/resonance issues.
Multiplex
Appease my earhole.
One additional funny resonance story...
I had set up a turntable system in my guest bedroom. Technics SL-QX300 with an AT92ECD, Nakamichi Stasis receiver, and Speakerlab tower speakers. My floor is a Pergo type laminate. The components were setup on a small end table with a speaker spaced at about 3' away on either side. I had played it a few times at low volumes and it sounded good.
One day, I was doing some house cleaning, so I put a record on and cranked it. It sounded fine for a minute or two, but then started to have this weird fluttery warble. I looked over at the system and everything was rocking back and forth! I could physically see it all moving! For a split second I wondered if it was an earthquake, but nothing else was moving. I went and tipped a speaker grille forward, and sure enough, the woofer was pumping in and out more than a half inch. Feedback! Technically, the turntable should perform pretty well in that regard. Suspended, Pmount with a T4P cartridge. There shouldn't have been a mismatch. I just think the system managed to find the resonant frequency of my floor!
I had set up a turntable system in my guest bedroom. Technics SL-QX300 with an AT92ECD, Nakamichi Stasis receiver, and Speakerlab tower speakers. My floor is a Pergo type laminate. The components were setup on a small end table with a speaker spaced at about 3' away on either side. I had played it a few times at low volumes and it sounded good.
One day, I was doing some house cleaning, so I put a record on and cranked it. It sounded fine for a minute or two, but then started to have this weird fluttery warble. I looked over at the system and everything was rocking back and forth! I could physically see it all moving! For a split second I wondered if it was an earthquake, but nothing else was moving. I went and tipped a speaker grille forward, and sure enough, the woofer was pumping in and out more than a half inch. Feedback! Technically, the turntable should perform pretty well in that regard. Suspended, Pmount with a T4P cartridge. There shouldn't have been a mismatch. I just think the system managed to find the resonant frequency of my floor!
sqlsavior
Lunatic Member
Resonance is the natural frequency at which something vibrates. It is illustrated and modeled as a mass on a spring. The lighter the mass and/or the stiffer the spring, the higher the frequency. The size of things is a main determinator of resonance, which is a sympathy between a wavelength and a dimension. A four foot 2x4 makes a higher sound when dropped than an eight foot 2x4, for example.
There are LOTS of things in a turntable that can vibrate, and the tiniest vibrations, if they reach the stylus, are made audible. That doesn't necessarily mean that they sound like anything in particular.
The tonearm/stylus resonance has been discussed the most here. One very common cause of visible woofer pumping is a tonearm/stylus resonance that is too low in frequency. The optimum frequency range is 8-12 Hz, below the audible spectrum, and above the typical record warp frequencies of 3-5 Hz. A 'dancing' tonearm is another possible indicator of a resonance that is too low.
There are LOTS of things in a turntable that can vibrate, and the tiniest vibrations, if they reach the stylus, are made audible. That doesn't necessarily mean that they sound like anything in particular.
The tonearm/stylus resonance has been discussed the most here. One very common cause of visible woofer pumping is a tonearm/stylus resonance that is too low in frequency. The optimum frequency range is 8-12 Hz, below the audible spectrum, and above the typical record warp frequencies of 3-5 Hz. A 'dancing' tonearm is another possible indicator of a resonance that is too low.
Everything in nature has a resonant frequency. It's physics.
The cantilever of your cartridge, the tonearm, plinth and platter each has it's own resonant frequency. When they resonate they start to vibrate and energy gets transferred to the stylus. This gets picked up and amplified and you have a feedback loop. You might hear a howl or actually see the cantilever shake.
I bought my current cartridge from a guy because he said the cantilever visibly shook in the groove, even with the volume down. He didn't do his homework before he bought that cartridge...it was incompatible with his tonearm.
I have The HiFi News Test Record which has bands that play different frequencies. As it hones in on my tonearm/cartridge's resonant frequency the cantilever begins to shake..violently.
All tonearm/cartridge combinations will resonate and shake at a particular frequency, that's unavoidable. The goal is to have it resonate lower than what your system can reproduce (to avoid feedback) but high enough so that things like footsteps don't start things up.
Hope this helps.
The cantilever of your cartridge, the tonearm, plinth and platter each has it's own resonant frequency. When they resonate they start to vibrate and energy gets transferred to the stylus. This gets picked up and amplified and you have a feedback loop. You might hear a howl or actually see the cantilever shake.
I bought my current cartridge from a guy because he said the cantilever visibly shook in the groove, even with the volume down. He didn't do his homework before he bought that cartridge...it was incompatible with his tonearm.
I have The HiFi News Test Record which has bands that play different frequencies. As it hones in on my tonearm/cartridge's resonant frequency the cantilever begins to shake..violently.
All tonearm/cartridge combinations will resonate and shake at a particular frequency, that's unavoidable. The goal is to have it resonate lower than what your system can reproduce (to avoid feedback) but high enough so that things like footsteps don't start things up.
Hope this helps.
Multiplex
Appease my earhole.
Maybe microphonic isn't the best word to describe this, but I think that it works... I was referring to when vibrations are "picked up" from the surrounding environment and reproduced by a device, much like a microphone. It's a term often used for aging vacuum tubes that start "hearing" sounds around them. To be more accurate, I should probably say "easily excited resonances," but that doesn't have quite the same ring to it.
Anyway, resonance happens when energy is introduced that excites vibrations in an object. The resonant frequency is the natural frequency at which said object wants to vibrate. (Think tuning fork. When you tap it, it will always resonate at "concert A", or 440Hz because of it's size and shape.)
Here's an example of energies exciting a resonance:
I have a small decorative gong in my listening room. It looks kinda cool, but it is actually a pretty dumb thing to have in there. When I really crank my system, vibrations in the air excite the metal material of the gong causing it to vibrate sympathetically. So if I am playing a CD loudly and suddenly hit pause, I can hear this faint .. gonnnng... decaying in the background. It's not very apparent most of the time, and it doesn't really bother me. But it probably measurably degrades my listening experience.
Now, as far as record playback is concerned, it would work best when performed while isolated in a vacuum. Nothing but a stylus and a groove, the only motion being the forward velocity of the groove and the vibrations of the stylus as it follows the contours of the groove walls. Nothing added, nothing subtracted, just a pure reproduction. Unfortunately, that's not possible. The cantilever has a resonant frequency. The cartridge itself can have resonances, as will the headshell, and tonearm, etc. Then there are all of the ambient vibrations. The point of playing records is specifically for making vibrations you can hear, so naturally your turntable will be immersed in vibrations. When these vibrations are introduced back into the playback system, they can cause various different materials of it's construction to resonate just as my gong does.
All of these excess movements, vibrations and energies come back into the stylus during playback. All of these movements added over the top of the music waveform will cause distortions. Increasing amplitude. Decreasing amplitude. New and different "squiggles" in the signal that weren't present in the original recording. It can be a lot like my "gonnnnng...." going on in the background... Or maybe more like a cacophony of several gongs.
Resonances from compliance mismatch are a little different, but still operate on much the same principle. The tonearm is a big heavy lever, controlled by the far tinier cantilever, which is mounted in springy material. How they interact can be viewed more like a car with bad shocks. Most of the time, the car with bad shocks will still drive sorta okay. That is, at least until you hit a big bump, have to swerve, or hit the brakes. When "excited," a car with bad shocks usually bounces up and down with a certain resonant frequency. The car won't handle well, because the tires aren't held to the road well enough. Same goes for your stylus tip. If it's not well controlled, as soon as the the going gets tough, excess energies will begin to make it lose control.
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Isaac C.
Cat Hoarder
I was having issues with my Thorens picking up environmental resonances, so I put a 1" thick granite slab between the turntable and walnut credenza. Now I can tap the credenza and floor and not here a "thud". It's crazy how much more clarity and dynamics the music has now. The best I can describe it is that prior to putting the granite under it it just had this undeniable wood sound quality to it. You could definitely tell the plinth and shelf was wood, it just kinda dulled everything. I guess the weight and density of the granite helped transfer those vibrations elsewhere.
Ok, great, I'm starting to get it. How does feedback occur and what are 'footfalls.'