I don't claim to be an expert, I'm not. I've spent the last 18 months obsessed with audio, the 18 months before I was obsessed with computers, which is why I now hang out in this section
I feel like I know enough to lay down some general thoughts and maybe they can help somebody, feel free to question or contradict me, I don't know all the answers.
So what makes a good speaker? Many things.
1) an Inert cabinet is very important, reflections from your cabinet color the sound and distort it, distortion is bad in terms of high fidelity, it turns music to mush, squishes the instruments together and muddies the imaging and soundstage. Play some music and lightly put your hand on the speaker cabinet, compare it with the the vibrations from the driver, if you can feel the cabinet vibrating then there's room for improvement, those vibrations are audible and they distort the sound that you hear, always for the worse. You can minimize this with both extra extra bracing and extra damping for the cabinets with materials such as bitumen, layers of dacron, foam, wool or maybe even duct seal. This can get rid of cabinet vibrations that color the sound. It's also a good idea to stuff the cabinet which can reduce long standing waves and reduce cabinet vibrations. The best materials to stuff a cabinet with are long haired wool, polyfill (best option is dacron) or fiberglass.. Many people argue the merits of each, my favourite is long haired wool, it's kind of hard to find, Madisound sells it fairly reasonably, you may find it in a local store like Joann (wool batting is fine if you can't find "long haired wool"). Some people say fiberglass is better and they may be right, I'm afraid to touch it as I think it may be the next asbestos, and for personal reasons that to me is a no go, so I won't use it. If you're braver than me, make sure you wrap it in speaker cloth so the fibers don't escape out of the cabinet (like if you have a ported system) or into the drivers and cause you havoc. Adding bracing will reduce the speakers internal volume, adding stuffing increases effectively the internal volume so if you add a bunch of bracing add some extra stuffing.
2)Drivers. All speaker drivers are is a piece of thin paper, aluminum, kevlar etc etc. There are many different materials to be used, in fact paper is actually really quite good, especially if it's been treated... This material is sandwiched between a piece of wrapped wire called the voice coil and a large magnet. The voice coil is an electro magnet and the speaker cone moves back and forth between the regular magnet and the electro magnet when current is applied. The best drivers have a large magnet, a large voice coil, cast aluminum frames to help with rigidity and heat dispersion. Chances are your speakers have stamped metal baskets, mine do to, because they are cheaper. They can still be excellent with a few mods.
3)Crossovers. Crossovers are what sends the correct part of the audio spectrum to the corresponding drivers. You don't send 50hz to a tweeter because it cannot reproduce it, same as you don't send 16khz to a subwoofer. Breaking the audio spectrum up and sending it to the corresponding drivers is what the crossovers do, the quality of components used can play a big part in how those drivers can reproduce sound correctly. They are usually a selection of inductors, capacitors and resistors. Higher end crossover components utilize air core inductors, generally for the mids and highs and ferrite core inductors for the bass woofers. Good capacitors are film or foil, these are pretty expensive. The crossover can effect what you here, but unlike other easy mods, tinkering with crossovers is difficult, you need to know what you're doing.. I don't actually, so I leave mine as they are, I didn't say I was an expert, just had an interest that doesn't seem to want to die. My speakers have cheap caps in them, but the inductors and resistors are fairly reasonable quality, so maybe I will replace the caps in time. Having said that there's a wealth of people who've reported big differences from rebuilding crossovers. Another route is to use active crossovers, though that is a topic I have no experience with.
4) You can mod your speakers, especially cheap speakers with good results. Add extra bracing to the cabinets with some plywood and wood glue, it's easier if your speakers are in curved cabinets as you can knock them into place, if you're in a square or rectangle cabinet you can reinforce the joints, some people have effectively added crossbracing using two pieces of wood attached together in the middle with a long screw (dual ends), , when it's in place they untighten it up so it braces both sides, google it, I don't feel I provided a good visual... If your speakers are housed in plastic then this won't work, but you can cover the plastic internally with bitumen or non drying clay and it will dampen cabinet vibrations. Add duct seal or blu tac (or something similar that is non drying) to the drivers at the point where the magnet meets the frame on your driver to diminish vibrations, add duct seal to the basket on the outside (usually four pieces of stamped steel) to stop vibrations interfering with the cone. Some people add velvet to the back of the magnet. (one point of warning if there's a hole in the middle of the magnet to allow heat to escape don't fill that in), if there is a hole that means your drivers have vented pole pieces which is a good thing, that speaks to quality drivers.
5) Mod Podge - I've never done this, it is an irreversible mod.. It's kind of like a glue, you can paste it on to the speaker driver cone like a layer of paint if it isn't very rigid and it will make it more rigid... Usually the more rigid a driver cone is, the better it sounds, but... you can't undo this.
6) I've seen guys on headfi, stuff their cans with long haired wool, I bet that is an awesome mod, I have some wool left over and a pair of cans, I will try this soon.
I just did a lot of this to my speakers and the results have been noticeable, it's definitely worth trying out mods... usually the cost of the materials is very very little and it doesn't take long.
Ok, this is fairly general, but I think I've said enough that if you google you can find the right way of doing things, it does make a difference and it's all very cheap.
I feel like I know enough to lay down some general thoughts and maybe they can help somebody, feel free to question or contradict me, I don't know all the answers.
So what makes a good speaker? Many things.
1) an Inert cabinet is very important, reflections from your cabinet color the sound and distort it, distortion is bad in terms of high fidelity, it turns music to mush, squishes the instruments together and muddies the imaging and soundstage. Play some music and lightly put your hand on the speaker cabinet, compare it with the the vibrations from the driver, if you can feel the cabinet vibrating then there's room for improvement, those vibrations are audible and they distort the sound that you hear, always for the worse. You can minimize this with both extra extra bracing and extra damping for the cabinets with materials such as bitumen, layers of dacron, foam, wool or maybe even duct seal. This can get rid of cabinet vibrations that color the sound. It's also a good idea to stuff the cabinet which can reduce long standing waves and reduce cabinet vibrations. The best materials to stuff a cabinet with are long haired wool, polyfill (best option is dacron) or fiberglass.. Many people argue the merits of each, my favourite is long haired wool, it's kind of hard to find, Madisound sells it fairly reasonably, you may find it in a local store like Joann (wool batting is fine if you can't find "long haired wool"). Some people say fiberglass is better and they may be right, I'm afraid to touch it as I think it may be the next asbestos, and for personal reasons that to me is a no go, so I won't use it. If you're braver than me, make sure you wrap it in speaker cloth so the fibers don't escape out of the cabinet (like if you have a ported system) or into the drivers and cause you havoc. Adding bracing will reduce the speakers internal volume, adding stuffing increases effectively the internal volume so if you add a bunch of bracing add some extra stuffing.
2)Drivers. All speaker drivers are is a piece of thin paper, aluminum, kevlar etc etc. There are many different materials to be used, in fact paper is actually really quite good, especially if it's been treated... This material is sandwiched between a piece of wrapped wire called the voice coil and a large magnet. The voice coil is an electro magnet and the speaker cone moves back and forth between the regular magnet and the electro magnet when current is applied. The best drivers have a large magnet, a large voice coil, cast aluminum frames to help with rigidity and heat dispersion. Chances are your speakers have stamped metal baskets, mine do to, because they are cheaper. They can still be excellent with a few mods.
3)Crossovers. Crossovers are what sends the correct part of the audio spectrum to the corresponding drivers. You don't send 50hz to a tweeter because it cannot reproduce it, same as you don't send 16khz to a subwoofer. Breaking the audio spectrum up and sending it to the corresponding drivers is what the crossovers do, the quality of components used can play a big part in how those drivers can reproduce sound correctly. They are usually a selection of inductors, capacitors and resistors. Higher end crossover components utilize air core inductors, generally for the mids and highs and ferrite core inductors for the bass woofers. Good capacitors are film or foil, these are pretty expensive. The crossover can effect what you here, but unlike other easy mods, tinkering with crossovers is difficult, you need to know what you're doing.. I don't actually, so I leave mine as they are, I didn't say I was an expert, just had an interest that doesn't seem to want to die. My speakers have cheap caps in them, but the inductors and resistors are fairly reasonable quality, so maybe I will replace the caps in time. Having said that there's a wealth of people who've reported big differences from rebuilding crossovers. Another route is to use active crossovers, though that is a topic I have no experience with.
4) You can mod your speakers, especially cheap speakers with good results. Add extra bracing to the cabinets with some plywood and wood glue, it's easier if your speakers are in curved cabinets as you can knock them into place, if you're in a square or rectangle cabinet you can reinforce the joints, some people have effectively added crossbracing using two pieces of wood attached together in the middle with a long screw (dual ends), , when it's in place they untighten it up so it braces both sides, google it, I don't feel I provided a good visual... If your speakers are housed in plastic then this won't work, but you can cover the plastic internally with bitumen or non drying clay and it will dampen cabinet vibrations. Add duct seal or blu tac (or something similar that is non drying) to the drivers at the point where the magnet meets the frame on your driver to diminish vibrations, add duct seal to the basket on the outside (usually four pieces of stamped steel) to stop vibrations interfering with the cone. Some people add velvet to the back of the magnet. (one point of warning if there's a hole in the middle of the magnet to allow heat to escape don't fill that in), if there is a hole that means your drivers have vented pole pieces which is a good thing, that speaks to quality drivers.
5) Mod Podge - I've never done this, it is an irreversible mod.. It's kind of like a glue, you can paste it on to the speaker driver cone like a layer of paint if it isn't very rigid and it will make it more rigid... Usually the more rigid a driver cone is, the better it sounds, but... you can't undo this.
6) I've seen guys on headfi, stuff their cans with long haired wool, I bet that is an awesome mod, I have some wool left over and a pair of cans, I will try this soon.
I just did a lot of this to my speakers and the results have been noticeable, it's definitely worth trying out mods... usually the cost of the materials is very very little and it doesn't take long.
Ok, this is fairly general, but I think I've said enough that if you google you can find the right way of doing things, it does make a difference and it's all very cheap.