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This is an area that often seems to confuse a lot of guitar and bass players. Hopefully this should help to demystify it.

Before we go any further - ALWAYS ensure you are using speaker cables! It is not satisfactory to use guitar cables for connecting amps to speakers. Guitar cables are not made to carry the current produced from amplifiers. The cable is much thinner and can easily burn out, leaving nowhere for the speaker load to go. This in turn can damage your output transformer and power amp tubes, leaving you with a hefty repair bill.

First you need to find out whether you're chaining the speaker cabs to your amp in series or parallel. Most commonly, you'll be connecting in parallel. In this scenario you'll have two separate outputs on your amp going into the two separate speaker cabinets. In series, you chain the speaker cabinets together with only one output from your amp. This is much more common with PA speakers (e.g. when adding a sub speaker).

Next, we need to find out the ohmage of the cabs. This is somewhat easier as it is often written on the back of the cab, or individually on the speakers themselves. If it's written on the speakers, then you need to use one of the below equations (depending on if it's wired in series or parallel) to work out the total impedance of the cab.

Now we're ready to calculate the impedance! Below Z(t) relates to the total impedance. Z(a) and Z(b) could relate to either the impedance of speaker "a" and speaker "b", or you could think of it as the total impedance of speaker cabinet "a" and total impedance of speaker cabinet "b".

For example, let's say we have two guitar cabinets, both rated at 8 ohms, and we want to connect them in parallel. Using the parallel wiring equation we find that z(t) is 4 ohms. All we now need to do is ensure that we are using the correct output jack for the calculated total impedance. Amps normally have a few different outputs for this purpose or a selector switch on the back.

This is incredibly simple to do and you'd be surprised how little the component parts cost to make a cable. The only tools you need are a soldering iron, a wire stripper and some solder, which will altogether cost around the price of a new cable. They should last you a long time though and allows you to repair cables as well as make new ones.

Below are wiring diagrams for just about any type of cable you'll need. Use the first table to find the code relating to the types of connectors you need, then look up the relevant wiring diagram in the other two tables.

table of connector types
wiring diagram 1
wiring diagram 2

For example, to make a guitar cable with unbalanced Tip Sleeve (TS) connectors, would be 15A according to the table of connector types. If you look at 15A on wiring diagram 2, then it shows you how to connect the internals for this cable type.

After doing live sound engineering for a few years, it's surprising to see the amount of musicians that do not pay enough attention to this. It's potentially very dangerous for you, your band members and your audience!

Don't daisy chain power strips!

Daisy chaining reduces any surge protection offered. Daisy chaining two four ways for example requires twice the original overload for a trip to occur.

Be wary of how much power a single socket can handle. The voltage standard in the UK is 230 volts, so for example, with a 13 amp fuse, you can safely run a maximum power load of up to 2990 Watts. This may sound like a lot, but if you have a power strip, then plug in a bass amp, two guitar amps, an effects board and a PA, you've pretty much used up all available power before the safety switch trips - assuming that it is functioning correctly!

Also watch out for double wall sockets. These are not 13A per socket, but rather 13A over the two sockets (see BS 1363).

Re-amping has become quite a common studio practice, but it's not a new development. In fact, the concept has been experimented with since the early 1900's. The technique in its modern guise was first recorded as being used by Les Paul in the late 60's, and said to be pioneered by Phil Spector when used to re-mix "Let it be" by The Beatles.

Its early application to guitar recording is said to of initially come around so that guitars could be easily separated from the other elements of a mix, rather than used for its tonal value. Remember, this is in the days where bands had to record their albums live!

So what is it exactly?

Re-amping is simply taking a previously recorded sound, playing it though a loudspeaker and then recording the new sound. You can do this with anything, but it is typically applicable to guitars and bass. For example, at the tracking stage, the engineer will split the signal coming from a guitar with a DI box. One output goes to the amp, the other is converted into a line level signal and goes straight into the recorder (this could be a DAW, Tape or Multitrack recorder). It is this latter signal that is particularly useful as it is just the "dry" sound straight from the output jack of the guitar. When the tracking has been completed, the signal can be taken back out from the recorder, converted back to guitar level with a Reamp box, and then plugged into a guitar amp. Essentially the recorder has now become the guitar player, except that we already have the perfect take!

Benefits and Disadvantages

This is an incredibly powerful tool, as it allows the engineer to try out different combinations of amps, speaker cabinets, mics, mic placement with no need for the musician to come back to the studio and do another take. This allows more time to be spent getting that perfect tone.

It also benefits valve amps, as under normal circumstances, tracking an album for a couple of days at high volume will quickly wear out your tubes. Think about it, it's like playing several gigs back-to-back!

For album recordings, it can also maintain a high degree of continuity of guitar sound between all the songs. It might take several days to track the guitars, but the tone can be captured in a few hours once the takes are there.

The only disadvantage to reamping is that with some guitars and tube amps, you may not initially be able to achieve a very high gain sound. This can easily be solved with a booster pedal though which will drive the tubes harder.

Other uses

As mentioned earlier, reamping can be used for any recorded sound. I've successfully re-recorded vocals and snares through an amp in the past as special effects. Even boutique guitar pedals can be used in a similar manner if there's a specific sound that you're after. It's not just a tool for getting a good tone, it's a highly creative way of increasing the production value of your mixes.

Vinyl releases differ greatly in audio quality to that of CD and digital media releases. This advice isn't intended to scare you into choosing digital media over vinyl as it's a fantastic medium for you to sell to your audience.

Vinyl presents a few areas that need to be treated with care. Whoever is mixing the recording needs to ensure that the overall levels aren't too hot, or overly compressed as this results in distortion. Too much high frequency content can result in a distorted vinyl cut, and stylus tracking problems can also occur if the low frequencies are out of phase. These can be fixed by the cutting engineer but will result in some odd side-effects, therefore it's best to get it right before the mix is sent off.

What is just as important though, and more to do with the decision of the band/artist, is the length of each side of the vinyl. The physical nature of vinyl means that there is high frequency degradation as the needle moves towards the centre of the disc. Unfortunately this is just a fact that we have to deal with, the reason lying in simple Mathematics.

The rotational speed of the stylus on the outside of the disc is faster than at the inner part i.e. the rotational speed is constantly decreasing as the record plays. Imagine you were to straighten out the outermost groove of a 12" record and lay it next to a straightened out innermost groove. The length of the inner groove would be less than half the length of the outer groove. But importantly, it still takes the needle exactly the same amount of time to travel along both. When a high frequency cut is made on to vinyl, the groove is very narrow and the needle moves rapidly to track it. Conversely, when a low frequency cut is made, it is a lot wider and the needle moves slower. If the groove is very narrow, then the stylus will have difficulty staying on it (this is one of the possible causes of the needle skipping). On the outermost groove, these narrow high frequency sections are stretched out and so don't cause the needle to move as fast. On the innermost grove, the narrow sections are severely squashed and the needle is moving frantically to try and track everything. In fact, the cutting stylus can move so fast that it effectively overlaps and thus wipes out part of the groove it made on the previous pass. It is this overlapping, caused by the faster needle movement which causes the gradual degradation.

In summary, try not to cram as many songs as possible on to vinyl. Consider having less material and reap the benefits of higher audio quality. There's always the opportunity to release double vinyl - popular with record collectors! If you're getting close to the maximum recommended time for your chosen vinyl format, then try to arrange your track listing so that you have mellower tunes towards the centre. You can find some suggested running times for various vinyl formats in the next article.

These times are meant as a guide and are not definitive. It is possible to go over the maximum times stated below. Always double check what running times are possible with your cutting engineer as the quality of the cut is very much dependant on their skill level. As per the article above, sound quality degrades as the time increases, so the times specified are a guide to sound quality! The lower the time, the better your vinyl cut will sound.

For further reading, please see http://www.chicagomasteringservice.com/.