Generally, the following order is accepted by most audio enthusiasts as the list of components arranged from the most to least important in contributing to overall sound quality:

• 1)   Speakers/Headphones
• 2)   Amplifiers
• 3)   Digital to Analog Converters (DACs)
• 4)   Sources
• 5)   Power
• 6)   Cables

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Even if speakers, headphones, and amplifiers typically make the biggest difference, this is not to say that a bad cable, source, or DAC couldn't ruin the sound.   Sometimes the overall sound quality that can be achieved is limited by the component that happens to be your weakest link.   In other words, if you have a poorly performing component, it should be replaced first.   In addition, I should probably note that when I refer to the quality of various components that doesn't always mean better is more expensive, and that is more thoroughly addressed in my Industry State & Resources along with terminology for describing sound.

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My overall equipment acquisition approach is the following.   Everything from cables through DACs provide the foundation for my audio system where I want to obtain reasonably good quality components that in aggregate produces a neutral to slightly warm sound signature.   With amplifiers including preamplifiers or integrated ones, I obtain a better quality component that again as a whole produces a neutral to slightly warm sound signature.   I wouldn't recommend going over neutral into a bright sound at this point.   This approach maximizes compatibility (synergy) with a wider range of speakers or headphones and increases the probability of an excellent sounding system without spending ridiculous sums of money or requiring multiple specialized setups.   Lastly, the headphones or speakers should be the best component and with all other components will determine the overall desired sound signature.   For headphones and speakers specifically, I prefer fairly neutral to warm sounding ones that when coupled with the other components will produce a slightly warm to somewhat warm sound.   Unfortunately, it is difficult to find frequency response graphs published by reviewers for speakers, but for headphones neutral might not look like a flat line on a graph.   This is because headphones sit really close to your ears, and they don't have a large volume of air to attenuate higher frequencies.   In short, I prefer at least a few dB increase in the low frequencies (from 20Hz to roughly 1000Hz) and a 3 to 5 dB decrease in the higher frequencies (mostly from 1000Hz to 2000Hz and proceeding to 20,000Hz).   In addition, speakers can be a little brighter if desired without too many problems because higher frequencies will attenuate more going through the air than other frequencies, and this is particularly true the further away the listening location is from the speakers.   By utilizing this approach, almost anyone should be able to generate multipurpose audio systems that sound excellent if you choose your components wisely.   Information to aid in the component selection process is contained in my Technology Reference.

It might be obvious that that I did not address Audio/Video (AV) receivers which typically encompass both DAC and amplifier components, so anything that applies to those components would apply to an AV receiver.   I used an AV receiver for years because of their value proposition and enjoyment of home theater.   Although, throughout the years I came to realize that many of the home theater audio mixes weren't really all that interesting.   Sure a few movies would feel like something flew over from time to time, but in reality that wasn't very often.   In short, it frees up a lot of money and floor/wall space to only have a 2 or 2.1 channel system, and I don't feel like I'm missing much including with my action/adventure movies.   Also, AV receivers do not provide the best value anymore.   Many include a wide array of technologies and features, and most of these devices are designed to hit a particular price point.   In short, adding all of these features puts pressure on the manufacturer to use cheaper internal components which can affect the overall sound quality.   For the longest time, I resisted utilizing separate components, but at this time I typically can find better quality components without paying for all of the features I don't use.   If you decide that an AV receiver is the right choice for you, just make sure the DAC chips, analog sections, and amplifier meet your needs/requirements especially considering sound quality in addition to all of the features/technologies supported.

When evaluating the impact of room acoustics on sound quality, it can be a lot larger than you think or expect.   There are three things that room acoustics can do to your speaker output such as cancel out particular frequencies, amplify particular frequencies, or induce excessive reverberations.   If any or all of these are happening in your room, you might notice it sounds muddy, unrefined, or simple just doesn't sound right.   Some try to cure these problems with digital room correction (sometimes built into AV receivers) which is basically an equalizer.   Unfortunately, equalizers can only cure one of these three problems, and that is reducing the amplification of particular frequencies.   If your room is canceling out specific frequencies, you can pump all of the power in the world into that frequency and it will not make much of a difference other than to waste a lot more electricity and put stresses on your components.   In addition, any equalizer can not fix excessive room reverberations.   This is basic physics, and there is no way around it.   Equalizers can be helpful in low-end setups especially to cure some undesirable frequency response issues or limitations with particular components, but I have found that hardware or software based ones can sometimes introduce additional audio distortions.   In short, I prefer to reduce the number of components or processes that modify the audio stream to insure the best audio quality because every time an audio stream is ran through another one you run the risk of additional distortions or processing errors.   These are the primary reasons why I do not address equalizers.   Anyway, how do I fix these acoustic problems?   Assuming you don't want to move, use another room, or build an audio studio (dedicated room), there are things that can be done to help.

The first step would be to get a baseline of the room, and the least expensive and best way I could find to do that was to use Room EQ Wizard.   It's a free Java based application that works with Windows, Macs, or Linux.   Although, I did have a few problems getting it to work at times including having to restart the application, restart the test and reconfigure the parameters, or reboot the computer; nonetheless, it has been several years ago so hopefully that has been corrected now.   With an inexpensive miniDSP UMIK-1 USB microphone obtained from and calibrated by Cross-Spectrum Labs and either an internal or preferably a good external sound card or DAC for enhanced accuracy, you can measure your room acoustics.   It was quite an eye opening experience for me.   I was able to discover my noise floor (background noise level), frequencies that were being canceled and amplified, and frequencies that were reverberating around the room and for how long.

Afterwards, some of the initial steps for making the room acoustics or sound quality better are simply:

• Move speakers out at least two feet from any wall or object if possible
• Remove any knick knacks or objects that might rattle or vibrate in the room (secure or utilize a soft material like felt under any remaining ones)
• Move main listening location out from the wall 2 to 3 feet and do not use any corners if possible (nearly in the middle of the room is the most ideal but not practical for most)
• Remove as many glass items from the room as possible
• Use heavy curtains on any windows and have them drawn closed when listening to audio
• Use thick carpeting or a large thick area rug
• Use heavy cloth furniture placed around the room

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After any or all of these steps, you can measure to see what differences they made as well as listen to some movies or music that is very familiar to determine changes or improvements.   These are some of the least expensive and probably the least intrusive from an aesthetics perspective to perform.   Did I do all of them?   No.   My main listening spot is comprised of two couches separated by an end table in a corner, and the main couch is along the back wall.   This can be an area where bass collects too much, but from an aesthetics and practicality perspective it was not reasonable to move them.   Everything else was done, but do I still have room acoustic problems?   Yes.   I still have some frequencies that were canceled out a bit and some that were amplified, but these issues were confined to very low frequencies only.   On the plus side, my reverberation problem was largely corrected.   In addition, if your room has dimensions that are evenly divisible this typically can cause problems with room acoustics, and there are some limitations on fixing that problem.

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If the room acoustics need further adjustments, the next step would be to deploy acoustic panels and bass traps around the room.   Acoustic panels can be placed on the walls and ceiling especially at reflection points where the sound most likely would bounce back to your main listening location, and large bass traps are typically placed in the corners and sometimes along the bottom of walls (for instance behind a couch).   Although, care must be taken to prevent the room from becoming too dead by adding too many panels or traps.   In addition, some build their own acoustic panels and bass traps out of wood, acoustic fabrics, and insulation to reduce the expense.   Nonetheless, all of these adjustments can only make improvements, but there is probably no such thing as perfection here.   This is not to say that a system can't sound good in a room, but be realistic about the level of sound quality that can be achieved.   I truly enjoy my speaker system, but with limitations of room acoustics this is another reason from an equipment acquisition perspective that I am only willing to invest so much into it.   In fact, if I'm looking for the ultimate in audio fidelity, I rely on my headphones.   The downside to headphones is that with the higher levels of accuracy, you can hear a lot of the recording mistakes that audio engineers made when creating the music.   It is surprising how often that happens.   Also, depending on how good the headphones are the soundstage might not sound correct or exhibit that in your head sound.   Although, the better ones typically do not have this problem.   Nonetheless, I could see why some prefer speakers over headphones or vice versa.   Personally, I enjoy both, but I do find myself listening a lot more on my headphones.   Regardless, I stopped short of utilizing acoustic treatments in my room.   This was in part due to expense, aesthetics, and quite frankly I reached a point where I was largely satisfied with the sound quality.   There are some rules that can be obtained from acoustic panel manufacturers such as specific decay time targets, but their goal is to sell more panels.   I believe it is a personal decision as to when to stop.

Once you have reached the point of personal satisfaction for the sound quality with acoustic treatments and/or audio equipment, my advice would be only make small changes as needed going forward.   This is the time to just sit back, relax, and enjoy the music.