Submarines will work on nearly all six string guitars. Electrics, acoustics, 12 strings, resonators, lap steels, bass VI type guitars. It will even work on instruments such as tenor guitars, mandolin, mandolas, bouzoukis. We have even found a way to get good results on nylon string / classical guitars. 
Our pickups are not designed for use with pedals steels, and other guitars with more than six strings. Although that does not stop people trying, and some have achieved good results.
Guitars with very arched tops or with scratch plate steps mean the microsuction pad may not work as desired. In these instances two (acid free, 3M) adhesive disc magnets are supplied. These can be stuck to your guitar to help overcome these difficult profiles. We also recommend black tac for curved profiles and difficult scratchplate positions.

The Submarine is 5.6mm thick at the E and A strings. The SubPro and SubSix have a minimum thickness of 6.0mm (without black baseplate) under the E strings.

In addition to this figure we recommend a string clearance of 3mm for gentle fingerpickers and 7mm or more for heavy strummers. Please note that the angle of the strings relative to the guitar body may mean that there is more space closer to the bridge.

Many of our customers have found it useful to place the following combinations of coins on their guitar to approximate the thickness of the Submarine before purchase.

In the UK, a £1 coin on a £2 coin = 5.65mm

With Euros, a 5 cent on two 10 cents = 5.53mm

In the USA, two nickels and a quarter = 5.65mm 

In Australia, $1 + $2  = 5.8mm

In Canada 2 x 10¢ on 2 x 25¢ = 5.6mm

For the Submarine and SubPro the maximum height that the pickups can be raised to is 15mm.
In addition to this figure we recommend a string clearance of 3mm for gentle fingerpickers and 7mm or more for heavy strummers, bringing the maximum distance to between 18 and 22mm. Please note that at the bridge most guitars’ strings will be further from the body.

The nanosuction pads will work with most guitars with a smooth or gloss finish. For matte guitars we recommend using either the adhesive disc magnets, or first applying a string of stick tape to the instrument and then positioning the pickup using the nano suction pad.
With acoustic guitars the SubPro and SubSix can be mounted directly into the sound hole and secured with the allen key.

As the pad picks up fluff and dust it will begin to lose its stick. Simply clean it with sticky tape or pvc tape using an on off motion, tapping the pad repeatedly with the tape until it’s clean. Do not use masking or gaffer/duct tape.

Replacement pads are available from our Spares section

The latest edition of the Submarine now has three switch positions.
With the switch in the 'back' position both strings are sent to the first output. With the switch in the middle position, only one string is heard. Push the switch forward and the Submarine is turned off.
For those wishing to take things one step further, switch to the middle position, plug in a Y-split cable, (available from our store) , and hear one string down the left channel and another down the right.Section 2 FAQs

78mm is the minimum acoustic guitar soundhole diameter. However the SubPro is thin enough that it may be possible to install above the sound hole. You could even position it between the sound hole and the bridge, on the guitar top.

Firstly make sure your pickups is close enough to the strings. Somewhere between 3mm and 7 mm is about right. Secondly if you are using fuzz, overdrive or distortion type effects the gain will inherently capture more of the surrounding strings. Either reduce the gain or if that is not an option consider using an expander before the pedal. If your guitar has a plain steel G and this is bleeding into adjacent strings you will have better results with a wound G. 

The level of our pickups when set up correctly is comparable to that of a vintage style pickup. However if you feel your output is low there are some things you can do.
Firstly make sure your pickups is close enough to the strings. Somewhere between 3mm and 7 mm is about right. 
The more strings you route to one output the lower the level will be. Depending on your guitar and playing style you may want to use a clean boost, pre-amp or compressor to give the signal a bit more gain when grouping more strings together.
For example say you wanted to group all six strings together, the output level might be too low. However, if you routed them into two groups and then summed them with a mixer or Boss LS-2 (or simply worked with them in stereo) you would have much better signal strength and signalk to noise ratio.

It really depends on your style of playing. If you are a strummer I would recommend starting with a polyphonic octaver like the EHX Pitchfork or TC Electronic Sub'n'Up. (I prefer the pitchfork over the POG). If you are a fingerpicker then I would highly recommend the analogue EBS Octabass

A compressor is not necessary but is a nice touch to give you extra sustain. It doesn't need to be anything fancy. If price and size are considerations I would recommend the Mooer Spark Compressor. Otherwise MXR are well designed and reliable and have a few different compressor options.

Could be down to a few things. First check that the pedal is getting enough signal. Is the Sub close enough to the strings? Use the supplied hex key to raise it closer to the strings. 

On acoustic guitars and some semi acoustics each note you play will have more upper harmonics. These are what make them sound good/interesting. However they can play havoc with monophonic octave pedals like the MXR bass octave deluxe or the EHX Multiplexer. If you have an EQ pedal or pre-amp try putting this in your pedal chain before the octave pedal. Roll off the treble and maybe some of the mid. Play with the shape of the sound until your octave pedal starts working properly. Whilst this is more involved than using a digital octave I find the results to be more rewarding.

If you have already tried the EQ then what about a compressor before the octave pedal in the chain. Bass guitar notes last longer because the strings are longer and more massive. They have more inertia. You can give your octave bass sound more sustain with a compressor. Depending on what pedal you use it can also shape the transient (the start of the note). Highly recommended.

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