How does guitar speaker size affect tone?
Over time, the 12-inch speaker has come to be regarded as having the best balance of attributes such as low end, harmonic complexity, power handling and high-note dispersion. However, there are some great sounding 10s and 15s that can offer some alternative, interesting and even exotic flavors.
Good quality 10s can deliver a fast, punchy sound at wider listening angles with reduced 'boom' on small stages. They can offer increased portability, reduced cost and the ability to push your amp into overdrive at reasonable levels without having drumsticks aimed at the back of your head.A well-designed 15 can move more air so you can gig those wonderful little valve amps. The vocal range can be creamier, with extended low end and lots of detail and harmonic complexity, giving surprising richness to some otherwise scratchy-sounding guitar and amp combinations.
For more background info, check out this article for more detail about size and the loudspeaker design process.
How old is my Celestion speaker?/When was my Celestion made?
Since 1956, all Celestion chassis drivers have been stamped with a date code (two numbers and two letters), denoting exact date of manufacture. The codes are added on the production line and are placed on the speaker's chassis leg, on the front gasket or, in more recent times, on a label on the magnet edge.
If you can track down the date code, simply refer to this set of tables, which provide an accurate record of the date codes used throughout the years.
My G12Ms have got black covers, how are they different to the Greenback?
Although the standard colour for G12M rear covers was green ('field green' it was called originally), G12M and G12H speakers were also made with black, as well as grey, beige and cream rear covers at various times. This was probably due to a shortage of the correct colour plastic to make them from (e.g. late delivery of the raw material). The different colour covers were only a cosmetic change not affecting the acoustic performance of the speakers in any way. Black, grey, cream, beige or green, they're all 'Greenbacks'.
Can I use 8 and 16ohm speakers in the same cabinet?
It isn't advisable to mix speakers of different impedances in one cabinet. This is because power will not be shared evenly between the speakers and it can cause frequency dependent shifts in the power balance. This will sound terrible, it can affect the amplifier and may damage the speakers. It is always best to use speakers of the same nominal impedance in one cabinet. (Similarly, it’s also advisable to have extension cabs with speakers that have matching impedances).
How do I break in my speakers?
Important Note! Before breaking it in it's advisable to "warm up" the speaker gently for a few minutes with low-level playing or background hum.
Break in a speaker with a fat, clean tone: turn up the power amp volume to full, and control the level with the preamp gain. Use a level that will be quite loud, but not painful in a normal size room.
Have the bass and mid up full, and the treble at least half. On your guitar, use the middle pick up position (if your guitar has more than one pick up) and play for up to an hour, using lots of open chords, and chunky percussive playing. This will get the cone moving, and should excite all the cone modes and get everything to settle in nicely. The speaker will continue to mature over the years, but this will get it most of the way to tonal perfection in the shortest time.
What is the difference between open and closed-back cabinets?
As a rule of thumb, closed back cabinets tend to project the sound forwards and yield a punchier, more structured tone with crisper definition. Contrast that with open back cabinets that are much more inclined to fill the room they are in, providing a more natural and organic sound with a greater ambient quality. I have heard people say that the Vintage 30 ONLY works in open cabs, and others say it ONLY works in closed so ultimately it's all down to personal taste, your tone and style, and how you set your amp controls.
Check out this article for more on open and closed back cabinet. Click here.
Is my speaker broken? How can I check if my speaker is working properly?
To check if you speaker is working correctly, first disconnect it from the amplifier by removing the wires from the speaker tag panel and then try these tests.
Gently move the cone in and out with your hand, the cone should move freely for a few milimetres before getting stiffer (do not force it or you could risk creasing the cone). There should not be any grating or scraping heard or felt. When released it should return to the equilibrium position in a 'springy' fashion.
Connect a battery across the terminals (we usually use a 4.5V radio battery). When the positive terminal of the battery is connected to the positive terminal of the speaker the cone should move away from the magnet assembly a small distance and stay there until the battery is disconnected.
Measure the DC resistance of the coil using a multimeter across the terminals. An 8ohm speaker should measure somewhere between 5 and 8ohm and a 16ohm around double that. If your readings are a lot different there may be a dry joint. Heat the tag with a soldering iron until the solder melts, then allow to cool. This will renew any dry joints. After a couple of minutes, you can re-measure.
Check the cone for tears or holes. These will lead to rapid failure, if they haven't already. Small tears often cause buzzing and can be repaired with balsa cement. Use a small amount on the edges of the tear, and hold it together until it's sunk in and stuck. Leave the speaker for a few hours before use.
However, not all audible problems are the speaker’s fault, buzzing is often caused by a cabinet panel or part of the amp that’s come loose. If you still have an audible buzz: press all the panels of the amp cabinet and chassis; ensure all the screws for amp and speaker are tight, and that no wires are resting on the back of the speaker cone.