If studio monitors have flat response, what makes some better than others?

Question

I am looking into replacing some consumer stereo speakers with proper studio monitors for my home studio. I understand that studio monitors have a neutral, flat response whereas consumer speakers introduce variations in frequency response designed to be more acoustically appealing, for lack of a better term.

I understand that studio monitors are available in various sizes for different volume levels, placements and budgets. But within a similar range by different manufacturers, how do you judge the quality of manufacturer A vs manufacturer B? If they sound flat, shouldn't they sound the same? Are you evaluating which is the most flat?

Answer 1

No such thing as flat response

There is no such thing as a speaker with a flat response - neither in theory (maths) nor in practice (electronics + mechanics) such a speaker can be built.

The term is often used like so:

Flat response, 60Hz - 20kHz, ± 5dB @ 100 dBSPL.

Which means that within the frequency range given (60Hz - 20kHz), when test signal was played at the given level (100 dBSPL), no frequency was 5dB louder or softer from the given level.

So 5dB is your 'error margin' and normally the lower the better (a figure of ±3dB is generally excellent, ±5dB considered good, ±10dB is little professional.

Consumer vs pro speakers

What is 'correct' is that consumer speakers are built to please listeners, while pro speakers are (more often than not) built to be 'true'. In other words, consumer speakers are 'coloured', while pro speaker strive not to be such.

A better 'flat' response is one criteria that pro manufactures try to improve. But there are many others - distortion levels, bass response, bass 'tightness' (for how long bass appears at the output, once no such exist in the input), efficiency, etc.

Pro manufacturers typically invest a lot of research to improve the various criteria and often use original component, designs and materials. Consumer speakers are often an assembly of ready-made components highly tweaked for cost-impression.

No way to compare

The spec sheets provided by manufacturers are hardly a thing to consult - not only these are lacking accurate specifications, but much depends on the test conditions and measurements chosen - manufacturers can easily 'cheat' by presenting the best tests and it is impractical to give specs that cover all frequencies at all levels with a large variety of test signals.

Anyhow, most people compare by ear. What is important to consider is that not all people work on the same type of music and thus there isn't 'one-speaker-fits-all'.

My experience shows that people just get used to their speakers and you have to remember that enormous amount of songs where mixed on the Yamaha NS10s, which were never intended for professional use and by all means have rubbish specs and a non-impressive sound.

What to look for

Although a matter of opinion, there are a few thing you may wish to look into:

• Are the speakers ported or sealed-enclosure - sadly due to cost tradeoffs, there aren't as many sealed-enclosure monitors as there are ported ones. Sealed enclosure monitors generally produce a more accurate and tight bass response, but the price you pay is often less bass.
• Frequency range / 'flatness' - the very measure shown above - how low the bass goes and what's the error margin (a higher error margin will also mean a lower frequency range; a 70Hz - 20kHz ± 5dB could be presented as 50Hz - 20kHz ± 10dB.

At the end of the day

• The more speakers cost the better their quality should be.
• You should make your decision based on listening to various monitors.
• It doesn't matter much - people just get used to their pair.

Answer 2

I don't think you'll find any monitors that are truly flat. Each brand and each set of monitors seems to have its own way it colors the sound. Choosing a set of monitors is one of the more personal choices you can make for your studio. Other things to take into account are the slew rate or how fast it reacts to frequency changes, transients etc. Bass response can be very different depending on if it's a 2 way or 3 way design, if it's ported, if it's meant to be used with a sub.

If at all possible I would recommend going to a store where you can listen to a range of different monitors with program material you are very familiar with. You'll find a set of monitors that make you happy mixing on them and give you what you want as far as accuracy, being able to listen to them all day, imaging, frequency and transient response and that are made to work well in your room hopefully.

Another thing to think about is - How flat/ tuned is your room. some people will obsess over +-2.5db in speaker response and put them in a room with +-16db of frequency response so even the flattest monitors aren't going to live up to their full potential in a situation like that.

Answer 3

Just because a monitor is flat at one particular target listening volume does not mean that it is either a) flat at all volumes or b) able to reproduce the same range of frequencies with the same dynamic range.

One set of speakers may be able to keep a flat response across a range of volumes and simultaneously produce both clear, quite sounds while still producing rich loud sounds as well, where as another speaker may become a total mess at low volumes and completely lose quieter parts of the sound.

In real world terms, imagine you are listening to a piano solo. One set of speakers may be flat both when the playing is loud and when it gets quiet and you may still be able to hear the sound of the hammers hitting the strings if you listen closely where as another set of speakers may only be flat when the piano is playing full volume and lose the ability to make flat sound at low volume. It may also not have the ability to render the subtle hammer strikes as it lacks the ability to move precisely enough while making the large movements associated with the larger sounds.

Additionally, you have to consider the spread of the sound from the speaker, is it focused in one direction or sent out evenly across the speaker's cone. Also, what is the actual build quality in how the speakers are made and how durable they are.

Basically, response curve is just one relatively minor and even correctable feature of a speaker. You could take a consumer speaker and EQ it to a more or less flat response with a decent 31 band EQ. There is far more factors to a good speaker design than that.

Answer 4

One thing that I don't see mentioned in the other answers but which some industry pros claim (or at least those at Polk do) is that having a very wobbly frequency response graph sounds (subjectively) worse than one that has smoother slopes... even if both fall within the same absolute bands (e.g. plus or minus 3dB).

It doesn't sound hard to believe in theory because we're more likely to distinguish intensity variations between nearby notes. We actually perceive rather differently the intensity of same SPL at large differences in frequency, so presumably some extra variation is hardly noticeable if the frequencies are far apart.

I'm not [yet] aware however of scientific (meaning controlled) studies confirming this hypothesis of the influence of the wobbliness of the frequency response on perceived quality.

Answer 5

When referring to near-field monitors being 'flat', it refers to them being unlike hi-fi speakers which tend to be bias towards or exaggerate certain frequencies. Therefore when nearfield monitors are refered to as flat it means they generally will have an even frequency response across the broadband spectrum, and not color the sound by exaggerating certain frequencies, in most cases the lower bass frequencies.

Here is an article that looks at this very principle that may further explain the differences between hi-fi and near-field monitors. http://www.soundonsound.com/sos/jun02/articles/monitors.asp Using near-field monitors gives you a good reference point to your mix, generally speaking if the mix sounds good on near-fields, it usually will translate well to other listening / sound systems.

It is worth noting that your room environment and its dimensions & whether it is acoustically treated will have more of an effect on how these sound than anything else. How your monitors sound at the store will sound differently to how they may sound in your room / home because of this. Generally as a rule of thumb bass frequencies like to build up in corners if they are not treated with things such as bass traps which can exaggerate the lower frequencies in your mix and how this translates may sound different on other playback systems. It is also worth looking at diffusion / absorption at things like the first point of reflection in a room (where the sound leaves your monitors and hits the walls to your left and right where the sound waves / frequencies hit and bounce back - ie reflection).

You can use hi-fi speakers as reference monitors, but what you are hearing through them will not actually be how the mix really sounds. If you are serious about how you want your mixes to translate, look at a good set of nearfield monitors and also what just as important is looking at how to position these in your room / monitoring area, also the importance of acoustically treating your room so what you are hearing is actually how your mix sounds.

YouTube have some great videos - look up Studio Rescue with Francis Buckley to give you and idea about monitor position & placement, sweet spot when monitoring, first points of reflection, absorption, reflection, diffusion. Edit : In summary, some of the best near-field monitors like the Yamaha NS-10 for example sound shitty...but translate really well on other playback systems when the mix sounds good on them. If it sounds good on near-fields like these, it will sound great on anything else