Woah.... This thread has died, oh well lets cram it with more imformation
Cabinets so many choices?
Many tone heads claim that the cabinet you plug into is equal to about ½ of your amps overall tonalities. So I thought I would have my say in the matter!!!
Speakers:
This is an obvious one! Of course speakers will affect the tone (unless you are using 100% transparent monitors.) Many manufacturers include graphs showing the Tonalities of the speaker. These are basically as easy as reading a Graphic EQ so I won’t go into it.
There are also many factors that contribute to the tone of speakers. Here is a brief rundown:
These are also referred to as Thiele/Small parameters.
FS:
This is also known as the air resonant frequency. A resonant frequency is the frequency at which the sound is loudest. This can give you a good indication of the speakers’ character (the same rule applies to pickups!). If a higher frequency is the resonant frequency, the general tone will be brighter than one with a lower resonant frequency. Generally a speaker with higher impedance also has a higher FS although there are exceptions. This is also important to know if you can find the resonant frequency of the enclosure. If they resonate at the same frequency (IE the speaker vibrates at the same frequency as the cabinet) it will ring uncontrollably!
RE:
No it’s not the lesson you had to sit through at school! It’s actually the DC resistance of the speaker. This to my knowledge does not really represent much as far as amplification goes. This is because a signal is essentially an AC wave rather than a DC one. It is important to know that RE is almost always lower than Nominal impedance, which most speakers are measured. Some have the fear that the amp will overload but in fact it won’t. Its hard to explain why, but its basically because as frequency increases the inductance also increases, meaning the amplifier will rarely see this load.
Qms, Qes a Qts:
Relates to the suspension when the driver reaches FS. These again have no real affect as far as tone is concerned. The Qts is equal to the sum of Qms x Qes / Qms + Qes. This Qts is also known as total Q,this represents th suspension affect of the transducer. Many recommend, that a Qts of 0.4 of below should be used in a vented enclosure and a Qts of 0.7 or above represents an open enclosure, could be used. This is just a guideline and you should really just follow your ears though!
VD:
In layman’s terms the amount of air that a cone can push. Hence a speaker that seems louder will have a higher VD. As will a larger surface area speaker (generally speaking)
BL:
This is a bit strange. The test they use (I believe) is: a mass applied to the cone, then the amount of force the cone is “pushing” back is the BL number. Basically this is the “power” of a speaker, its not really “power” per se. It’s more like the strength that the transducer is applying to the cone.
EBP:
This is also similar to Qts. EBP is the symbol used in many enclosure design formulas, in speakers it is used to determine whether the speaker is better suited to a closed of open enclosure. A rating of around 100 usually represent the speaker is suited towards an open-vented enclosure, where as a rating closer to 50 is normally suited to a closed back enclosure.
Sd:
Is the surface area of the speaker and is usually expressed in cm squared.
Xmax:
Represents the speakers impedance at resonant frequency (FS).
Those are the real Thiele parameters that really affect the usability of the speakers. But also there are also usable frequency ranges. This represents the point at which the frequencies are useful. Another way of thinking about it is: when you stand in front of a single speaker combo or cab, when you stand perfectly in front of it, its sounds weird but if you move to one side it goes. The “weird” sound is known as beamy or narrow. This affect is dependant of speaker size and frequency, as you want to try and avoid this don’t pick a speaker that does this at a musical note, (say middle C). Here is a few examples.
Speaker size: Frequency:
6.5” 2,672Hz
8” 2,105Hz
10” 1,658Hz
12” 1,335Hz
15” 1,052Hz
There are many ways of measuring this affect. The numbers I have taken are the ones Eminence speakers use.
Next we have power handling. This should be either an obvious or complex subject depending on your musical preference and style. Firstly you need a speaker at least the rating of you amp, these ratings are normally conservative but still don’t go under them. That is the simple part; the more complex part comes from the old rock ’n’ roll “vintage” style of music. The earliest type of distortion used was speaker distortion. It occurs when the speaker simply can’t get any louder and therefore distorts. This characteristic sound is normally associated with the old alnico Jensen’s of yesteryear! It gives that trademark thick, rich overdrive with very low gain. The problem is choosing a rating. You don’t want to run the risk of blowing a speaker so you have got to be careful. Of course with most modern playing styles this type of distortion is best avoided!
Magnet types:
As with pickups there are two main types of magnet used, either the old faithful Alnico or the Ceramic magnets. The short source of alnico means it costs a bomb to buy enough to make a heavy speaker hence the prices of some! As a general rule Alnico is generally warmer, sweeter with richer harmonics where as ceramics are usually classed as more muscular and aggressive sounding. Although this isn’t always true and is just a basic generalisation, because no musical signal actually flows through a magnet so the magnet itself isn't invollved with tone shaping. Its actually the strength, weight and design around the magnet that affects tone.
Efficiency and sensitivity:
The sensitivity of a speaker is generally a rough indication of how loud it is going to be. If you take a 10w 100dB sensitivity speaker and compare it to a 100w 97dB speaker, you should find the 10W to be louder! But remember because it is louder it doesn’t mean it will handle a higher power rating. (if you plug into a 30w amp it would most likely break!)
Speaker size:
As stated above about the useful frequency range, size matters! But not necessarily is bigger always better. 12s are normally used exclusively used these days but always remember there are other sizes. People believe that 10s are bright and 15s are boomy, but as a lot of other things regarding the music industry these are myths. They do have different frequency responses but still a 10” cone could be made to make as much/more bass than a 15”.
The most dramatic affect that speaker size has on tone is the delay/response time (AKA attack). This is a very tiny time that is barely measurable but does actually affect the tone. If you take 10” cones they have smaller cones and therefore less space for the cone to travel to produce a sound. The results give a quicker more articulating notes, with a load of definition and character! Which normally accounts for the “jumpy” highs! On the other hand 15” cones produce a slower response time due to more space for the cone to travel in. Therefore they are slower producing a slightly less articulating attack. Which in turn can seem like the highs are less lively, making them seem bassier! As you would expect 12” cones are in the middle!! And is probably why many players favour them!! (Remember you can go higher or lower than 10s/15s but expect the effects of smaller or bigger cones to be amplified (pun intended!) )
Cabinets:
A cabinet is just a place to hold your speakers, and maybe rest a cold beverage on right? Wrong again their Jimmy. The amount of factors that affect an amps tonality and response are endless, way more than the factors that affect a guitars tone. The cabinet choice when paired with a speaker choice makes up roughly 50% of the amps tone, according to some experts.
Material:
This is an obvious one! Just like the wood of a guitar affects its tonality so does the cabinet wood. Just like any other instrument the way in which the wood resonates colours the tone. Although you also have to remember though that the strength of the wood plays apart, you don’t want the cab to break when inside the back of a van do you! The industry standard material for making cabinets with is pine, which is usually plied to increase strength. I am sorry to disappoint anybody but I doubt that it is possible for the actual wood to make a difference (Eg. Pine Vs Ash or whatever. Most cabinets are covered it thick animal glue and tolex. This would hinder any chance of resonation, I believe that it’s the stiffness, thickness, and construction (ply V solid) that would make any difference, if anything))
Generally speaking plywood or chipboard doesn’t resonate as well as solid woods. Although resonation is not necessarily a good thing. Some claim a solid wood cabs make a “woolly” or unfocused. On the other hand some people love that vintage Bassman sound and think it’s the dogs!
Open Vs. Closed:
This is a VERY long debate, which, in fact has wasted a lot of time when we should be practising! (Just like the Set neck Vs. Bolt on argument) Most people know the differences between the two and have already made judgements for those people feel free to ignore a lot of this part. This is mainly for people who don’t know much about either or what exactly the sound like.
The best way to find out the difference IMO is to go down to your
music store and try two identical (or very similar) models of cab through the same amp and note the differences. A Closed cab has a piece of wood bolted across the back of the cabinet so you are unable to see the speakers’ magnet, whereas an open cabinet has nothing. (There are wide varieties that are ½ or ¾ closed which is like the fail-safe middle ground as far as cabs go.)
Open:
They sound more natural and transparent generally, with a wide almost surround sound feel. They also sound more “realistic” to some people’s ears. There is also an emphasis on the highs although the
bass response usually suffers due to the fact that there is partial phase cancellation due to the sound dispersing out of the back. I have to say though don’t worry about recording issues due to the phase cancellation because it is only slightly present (hence the word partial.) Also because the speaker “drives” in a multi-directional manner it seems to be louder than an identical closed back cab.
Closed:
One of the main attractions of a closed back cab is the astounding low end, which is often fuller and tighter in tonality. Because the sound is only projected in one direction the mids are often said to be overly compressed or spongy. The high end response is said to suffer from this construction method as well all though I believe that the increased amount of low end makes there seem like less highs.
As with every part of gear choice neither is better just different. Nobody can make a choice for you its all up to you! I hope this has made the choice a little easier but we still have more points to cover!
Wiring:
Without taking into account the changes in impedances (which you should know already through the resistor parallel or series rules!) lets look at how the different wiring approaches affect tone. First lets look at safety. If you have two speakers in series, imagine one breaks what would happen? A broken OT most likely! Because you are running one into another if one of them breaks the circuit is broken, meaning no load is on the OT, which will destroy it. On the other hand if you wired them in parallel, the chance is reduced because when one blows the other keeps working. Keep in mind that the impedance will then change so still run to turn off the amp, but at least you will have more time to save your baby!
With that out of the way lets look at the tonal differences!
Series:
Generally speaking speakers that are wired in series sound looser and more “sloppy” which you may think is a bad thing but not always. This is also paired with less of a damping effect, which in turn makes it sound raw or unprocessed and open sound. So you can see it gives more of a Blues scream tone rather than smooth jazz although this is just a huge generalization.
Parallel:
Parallel wiring is another way to make a cab. Yet again it gives different results tonally. Generally the break-up on speakers end is smoother with a tighter bass response. It also has a large damping effect, which you can see as a good or bad thing.
There are other “hybrid” configurations that you can use, which give results that rest in between the other two styles!
Multiple Vs Single:
Here is another life-long argument about what is “the best” either many speakers or a single speaker. This is a VERY long debate and I don’t want to cover it in too greater detail because almost everyone knows the difference between them. Obviously more drivers will push more air to the listener’s ear, which in turn will make the amplified level seem to be larger.
The way in which it affects “tone” is a little complicated if you want it to be! I am not about to jump into a huge long theory about the human ear and how it works so here is a quick answer to how it affects tone. The more speakers there are in a cabinet the more there will be an effect similar to phase cancellation. This in turn increases bass response. Also as there are more speakers they react to the signal being passed through them at different rates, this is also true about the same make, model or any other similarities the speakers may have. This creates a sort of harmony and blending of sounds, which has become very desirable. As it can often be linked to almost any classic rock/metal band of the past! Some people also blend different models of speaker to create desired affects. There is no set way to do this and you never quite know what you will end up with but generally most people use on bassy speaker and one bright speaker together for good results, nothing is set in stone so experimentation is the key!
Baffle:
The baffle is the board that is in the front of the cabinet that holds the speakers, for those who didn’t know. There are many variations and ways to do things which all produce different effects. I like to think of the baffle as like the neck joint on a guitar, because it connects the speaker to the cabinet so it can help/hinder resonation. Generally speaking older cabinets are made with thinner and looser baffles. These pass the vibration more strongly onto the cabinet which helps make it resonate more. This style of baffle is generally not used as much as it used to because it is considered to be unfocussed and “woolly”. The tighter the baffle it clamped onto the cab the less the vibrations will be passed on, this will make more of the speakers tonal qualities to shine through. It also makes the cab have a tighter better-defined low end.
Cab sizes:
The size that a cabinet is made also affects the tone. I will not go into the great details of how and why all this happens I will just give the facts. As a rule of thumb a deeper larger cabinet would make a larger bass sound, where as a smaller cabinet would make a brighter sound.
http://www.webervst.com/spkrcalc/closed2.htm
Here’s a link about working out the tone of different sized closed back cabinets!!
Enjoy!
