As a number of pieces on this blog have already noted, turntables are finicky beasts. Very small points of setup and maintenance can have a significant effect on performance and this can be a real pain. At first glance, there doesn't appear to be much in the way of upsides to this but I'm pleased to report that isn't the case. The way that turntables respond to aspects of their setup means that there are a number of well established aftermarket means to take advantage of this.
As such, this piece is going to look at three categories of upgrade, some decent options available to you on the market to make use of them and the improvements they are supposed to bring to the performance. They are arranged in the order that I think they make the most sense to apply to a normal turntable (and I'll cover where this might be an exception).
Turntables are sensitive to the affects of the outside world. Vibration from speakers, footfall, even traffic passing outside your house can all produce interference that travels through the stylus and into the audio path. Very few single processes can have as much of a positive effect on the performance of your deck as getting it isolated.
So what's the best option? Simply put, nothing can match a good wall shelf for getting the job done. Mounted on an external or structural wall, it will ensure that almost regardless of what is going on in the room, your deck will be unaffected by it (and on a more pragmatic level if you put a shelf up high, it will be unaffected by pets, small children and other traditional hazards).
Depending on the size and weight of your turntable, you can often find something suitable for the task in a hardware store but with one eye on the future, a dedicated shelf can make more sense as it will have the carrying capacity needed to support a different deck in the future. Dedicated turntable wall brackets are available from manufacturers such as Pro-Ject, Rega and Quadraspire.
If you can't get your deck up on the wall, there are some other options open to you. The first has nothing to do with the turntable itself. If your speakers are on the same playing surface as your turntable, you can help things enormously by getting them off it. Either by moving them to another location or (better in every way) getting them onto dedicated stands will help both your deck and speakers enormously.
If this isn't possible, you can look at a spot of DIY isolation. If you take a pair of paving slabs (or kitchen work surface sections which I prefer as they tend to be naturally balanced and slightly less brutal to look at) and place an inflated bicycle inner tube between them, you have a seriously capable piece of isolation. Dedicated (and slightly prettier solutions exist but there isn't much that can match the slab and innertube solution.
Almost all decks will benefit more from being isolated than anything else on the list but if you have a deck with a suspension system built in, you might benefit from looking at some other options on this list first. The suspension should provide them with an inbuilt degree of isolation that unsuspended designs don't. Of course all the comments about protecting them from other things in the house still apply suspension or not.
The relationship between the platter of a turntable, the record placed upon it and the stylus sat in the groove of a record is a fairly complex one with each item having a resonance point on its own and a different one when combined. An aftermarket mat can be used to change this resonant relationship and with it the signal that the cartridge receives.
Exactly what mat you choose is going to depend hugely on the materials used in your turntable. Many decks (at a variety of prices) use a steel or aluminium platter. This can be resonant depending on the thickness and construction and even when it is almost totally damped, it is fairly rare for a record to be placed directly on the metal playing surface. As such, manufacturers will usually supply a mat with the deck to act as a damper between platter and record. Depending on the cost of the turntable, it is more than likely that aftermarket mats might do a better job. In these cases, cork or a rubber compound is likely to be most effective.
Glass platters are a slightly different case because their resonant frequency is different to metal so while cork is effective here too in terms of providing a better resonant match, fabric is actually fairly effective as an option too. With glass, there is a greater area of subjectivity as to what you can seek to achieve with mats so different materials will have a varying effect on the sound which you can use to your advantage to give the system a little fine tuning- taming a brighter top end with cork and putting a bit more sparkle in with an acrylic one for example.
Acrylic platters are a different case entirely because technically, a mat shouldn't be present at all. Acrylic (as well as related materials like Delrin and PCC) has the same resonant frequency as vinyl so there should be no mismatch between them. As such, introducing a mat should only really be done if you are looking to change the presentation. As well as acrylic, any turntable that has a treated playing surface- cork topped platter or one made of a sandwich of different materials- will probably not automatically benefit from a mat but you may find the change it makes to be a positive one in the context of your system.
As to recommendations, the Simple Mat Record Mat is an excellent cork option for around $25 as is the slightly harder to find one from Tonar. For fabric, the Pro-Ject and Rega examples are both very capable (although if you can find a leather mat, these can offer excellent performance. One of the strongest performers of the lot is the Funk Firm Achromat which uses a unique 'blown' acrylic material and provides superb decoupling from the rest of the deck. This is a pricier option at over $100 but it can do things in terms of resonance control and isolation that more affordable mats can't.
When talking about clamps, the most important thing to discuss is what a clamp isn't designed to do. While it might look like the sort of thing that's just the ticket for helping flatten out a pesky warp, this is, at best, secondary function. The purpose of a clamp goes back to the same resonances that mean mats are useful. Clamping a record means that this resonant relationship between the record and platter is a close as it can be and then serves to dissipate more of this stray energy through the bearing rather than back to the stylus.
Your choices of clamp will break down into what your turntable's spindle will allow. If you have a deck with an unthreaded type spindle (and this will be most of them), you will be looking at a clamp that simply sits over the centre of the record and grips the spindle using a variety of different processes. Some clamps are surprisingly light and rely solely on the materials they are made from and the gripping mechanism to produce results where others are reliant on mass to do what they do.
If your turntable has an aftermarket clamp made by the manufacturer, this is almost certainly the best option as its weight, size and fixing process will have been decided with that turntable in mind. This especially applies if you have the option to switch the turntable to a threaded spindle and screw clamp. This pairing offers a superb fit and really does work to quell resonances (as well as work quite well at flattening warped records) so if this is an option is available, it would be your best bet.
For aftermarket options, the KAB Record Grip MkII is an excellent affordable clamp while for a bit more money, the Clearaudio Concept clamp is a clever and effective option.
Getting more performance out of your existing turntable can be a useful way of staving off the desire to spend big bucks on changing the whole deck. In addition to this, something like a good wall shelf or isolation platform will likely be as useful to any turntable in the future as well. As ever, different decks will benefit in different ways from these tweaks but there should be something here that can yield a bit more performance from almost any system.