This thread is a spinoff of the Analogue - the gloves come off thread on PF ages ago.
A bit about me first. My first work as an engineer was in noise and vibration research. This began in 1971 and I started work at Garrard in the R&D department in 1975. I had been working part time in motor racing and the offer to work full time in F1 came in 1976, so I wasn't there quite a full year. OTOH I already had loads of experience measuring and controlling noise and vibration before then and had been writing my own software since 1970. This was fairly unusual back then.
Garrard were very much about understanding how the things worked, and had just installed a laser vibration measuring system, certainly the first I had ever heard of at the time. As clever engineers the objective was to achieve the highest performance at lowest manufacturing cost. It seems to me this is not always welcomed by the customer/dealer - usually dearer stuff is assumed to be better, whether it is or not. In fact for most reviewers it seems to be the main criterion.
I consider well engineered to mean that the physics is understood and properly taken into account in the design. It should mean less expensive, since an engineer is a person who can do for 5 bob what any fool could do for a quid. I have seen several beautifully made and presented components which were not well engineered at all, good craftsmanship but weak understanding.
Anyway, a record player is just a vibration sensor system. I was told at the time that all the record player needs to do is turn the record at 33 1/3 rpm (45, 78...). The problem is it must not do -anything- else, and that is very difficult indeed.
With modern software being so inexpensive, and computers powerful, it is quite feasible to model the whole dynamic system. Looking on the analysis at the relative movement between the coils and magnet in the cartridge effectively gives the output the phono amp sees, so a comparison between this and groove modulation will show any errors in the transduction. It would also be possible to look at the influence of input through the feet and airborne disturbance.
I would assume any serious manufacturer is doing this. OTOH it seems to me that styling has a much bigger influence on the saleability than anything else, and some beautifully made products are on the market which look like styling was the be-all and end-all of the design.
So lets look at the output from the system - what the phono stage sees. In fact, assuming the generator system is good (it isn't always) the output is a voltage proportional to the relative velocity of the coil in the cartridge to the magnet. In stereo there are two coils which should be at 90 degrees to each other and not coupled to each other.
Now -anything- influencing this relative velocity will be producing output, regardless of whether it is on the record or not.
What, then, can be producing some extra output?
Firstly, the accurate part of the frequency response of the transduction system, were there to be no damping, would extend from about twice the natural frequency of the arm cartridge mass on the cartridge cantilever suspension stiffness to about half the resonant frequency of the cartridge tip mass on the stiffness of the groove wall. What addition do we get here? Well with no damping the potential oscillation of the arm when this first natural frequency is excited would be excessive (theoretically infinite) so damping is needed to prevent footfall, warps etc to create big problems. Unfortunately, the correct location of this damping would be between the cartridge body and the record surface. This is not very practical, though Shure did provide damping here on some of their models via a brush on a damped suspended stylus guard. Whilst this is certainly the best location for the damping this solution probably feeds a bit of brush needle-talk to the cartridge body which may defeat the object (I dont know whether it is a real problem or not, I havent tried it, but it got criticism from reviewers who seemed not to understand what Shure were trying to achieve).
The second best way I have seen is the Townshend Rock system which makes one side of the damper the plinth (therefore not dealing with warps correctly) but probably locates the damping better than a conventional arm. Unfortunately there are very few low-damping cartridges which would be an ideal match for it.
Since historically arms and cartridges are separate (this is not really a good engineering solution) the compromise adopted is to put the damping between the cartridge body and the cantilever within the cartridge. This short-circuits the stylus to the body dynamically over the whole audio band reducing accuracy of transduction (unusually, information is lost rather than added here) in a frequency dependant way completely influenced by the cartridge and arm in use.
Secondly, any deviation from the correct speed frequency modulates the output.
Thirdly any mechanical vibration produced by the motor, transmission system and bearing will be added to the cartridge output to an extent completely dependant on the design of the turntable. This is influenced by bearing design, motor design, power supply quality, mechanical isolation of motor from platter (if any). All this adds to the cartridge output.
Fourthly any sound in the room will excite various parts of the turntable some of which will not be isolated from the cartridge. This will add to the cartridge output at frequencies and amplitudes which depend on the design of the record deck.
Fifthly any structure borne vibration, caused by footfall, furniture vibrating in time with the music and transmission from the speakers via their stand to floor and then the turntable support. This, again, adds to the cartridge output at frequencies and amplitudes which depend on the floor design, where the turntable is located in the room, whether it is a suspended (isolated) type, where the speakers are located in the room, how the speakers are supported (are they spike coupled to the floor or on isolating mounts for example)
Of these effects, it seems to me that the losses due to the traditionally incorrect location of the cartridge damping is probably the most detrimental - probably why I like Decca cartridges so much.
The additions due to isolation shortcomings and various resonances in the structural parts of the record player can all be tuned to sound nice - like adding a bit more reverb on top of that already added by the recording engineer.
A bit about me first. My first work as an engineer was in noise and vibration research. This began in 1971 and I started work at Garrard in the R&D department in 1975. I had been working part time in motor racing and the offer to work full time in F1 came in 1976, so I wasn't there quite a full year. OTOH I already had loads of experience measuring and controlling noise and vibration before then and had been writing my own software since 1970. This was fairly unusual back then.
Garrard were very much about understanding how the things worked, and had just installed a laser vibration measuring system, certainly the first I had ever heard of at the time. As clever engineers the objective was to achieve the highest performance at lowest manufacturing cost. It seems to me this is not always welcomed by the customer/dealer - usually dearer stuff is assumed to be better, whether it is or not. In fact for most reviewers it seems to be the main criterion.
I consider well engineered to mean that the physics is understood and properly taken into account in the design. It should mean less expensive, since an engineer is a person who can do for 5 bob what any fool could do for a quid. I have seen several beautifully made and presented components which were not well engineered at all, good craftsmanship but weak understanding.
Anyway, a record player is just a vibration sensor system. I was told at the time that all the record player needs to do is turn the record at 33 1/3 rpm (45, 78...). The problem is it must not do -anything- else, and that is very difficult indeed.
With modern software being so inexpensive, and computers powerful, it is quite feasible to model the whole dynamic system. Looking on the analysis at the relative movement between the coils and magnet in the cartridge effectively gives the output the phono amp sees, so a comparison between this and groove modulation will show any errors in the transduction. It would also be possible to look at the influence of input through the feet and airborne disturbance.
I would assume any serious manufacturer is doing this. OTOH it seems to me that styling has a much bigger influence on the saleability than anything else, and some beautifully made products are on the market which look like styling was the be-all and end-all of the design.
So lets look at the output from the system - what the phono stage sees. In fact, assuming the generator system is good (it isn't always) the output is a voltage proportional to the relative velocity of the coil in the cartridge to the magnet. In stereo there are two coils which should be at 90 degrees to each other and not coupled to each other.
Now -anything- influencing this relative velocity will be producing output, regardless of whether it is on the record or not.
What, then, can be producing some extra output?
Firstly, the accurate part of the frequency response of the transduction system, were there to be no damping, would extend from about twice the natural frequency of the arm cartridge mass on the cartridge cantilever suspension stiffness to about half the resonant frequency of the cartridge tip mass on the stiffness of the groove wall. What addition do we get here? Well with no damping the potential oscillation of the arm when this first natural frequency is excited would be excessive (theoretically infinite) so damping is needed to prevent footfall, warps etc to create big problems. Unfortunately, the correct location of this damping would be between the cartridge body and the record surface. This is not very practical, though Shure did provide damping here on some of their models via a brush on a damped suspended stylus guard. Whilst this is certainly the best location for the damping this solution probably feeds a bit of brush needle-talk to the cartridge body which may defeat the object (I dont know whether it is a real problem or not, I havent tried it, but it got criticism from reviewers who seemed not to understand what Shure were trying to achieve).
The second best way I have seen is the Townshend Rock system which makes one side of the damper the plinth (therefore not dealing with warps correctly) but probably locates the damping better than a conventional arm. Unfortunately there are very few low-damping cartridges which would be an ideal match for it.
Since historically arms and cartridges are separate (this is not really a good engineering solution) the compromise adopted is to put the damping between the cartridge body and the cantilever within the cartridge. This short-circuits the stylus to the body dynamically over the whole audio band reducing accuracy of transduction (unusually, information is lost rather than added here) in a frequency dependant way completely influenced by the cartridge and arm in use.
Secondly, any deviation from the correct speed frequency modulates the output.
Thirdly any mechanical vibration produced by the motor, transmission system and bearing will be added to the cartridge output to an extent completely dependant on the design of the turntable. This is influenced by bearing design, motor design, power supply quality, mechanical isolation of motor from platter (if any). All this adds to the cartridge output.
Fourthly any sound in the room will excite various parts of the turntable some of which will not be isolated from the cartridge. This will add to the cartridge output at frequencies and amplitudes which depend on the design of the record deck.
Fifthly any structure borne vibration, caused by footfall, furniture vibrating in time with the music and transmission from the speakers via their stand to floor and then the turntable support. This, again, adds to the cartridge output at frequencies and amplitudes which depend on the floor design, where the turntable is located in the room, whether it is a suspended (isolated) type, where the speakers are located in the room, how the speakers are supported (are they spike coupled to the floor or on isolating mounts for example)
Of these effects, it seems to me that the losses due to the traditionally incorrect location of the cartridge damping is probably the most detrimental - probably why I like Decca cartridges so much.
The additions due to isolation shortcomings and various resonances in the structural parts of the record player can all be tuned to sound nice - like adding a bit more reverb on top of that already added by the recording engineer.