Choosing the right Studio Monitors
An extract article from our boards by Senior Member Tony Miro - Professional AES registered Mastering Engineer.
About Studio Monitors
Monitors that are designed for tracking/mixing studios are not designed to be flat across the 20-20kHz response range. All of them start to roll off significantly above 20Hz, some as high as 80Hz. All of the spectrums that I've seen also show that they tend to be voiced to produce a lift somehwere in the low frequency range from 60-150Hz and/or also in the midband, usually around the 2-6kHz: exactly where depends on how the monitor is voiced, whether its a closed or open design, speaker maufacturing, crossover and so on. Essentially monitors that are designed for tracking/mixing tend to be designed to emphasis the bass and and vocal presence but cannot produce low and sub bass and so flatter the sound a bit.
The closest you can come to flat are monitors that designed specifically for mastering. These tend to be flat from 40Hz up to 20kHz, with a gentle roll off around 40-60Hz. Monitors for mastering though are expensive, 'cheap' ones - i.e K&H300D - start at @4000USD and the better ones i.e ATC and PMC are over 10k USD.
To get a good, accurate response from mastering monitors also requires that you have a suitable room that has been treated properly and that the monitors are sited correctly. A suitable room isn't just about treatment its also about size, shape and how it was built. Treatment nearly always requires considerable bass trapping - treatment in recording/mix studios tends to be much more about high end reflection. To site your monitors means that they must be placed on heavy, inert stands (ours cost 1400USD) and in open space with nothing between you and the monitors to allow the sound and the reflections to develop properly. By nothing I mean that literally, put a mixing desl, a computer monitor, anything infront, or between them and you will get odd reflections, comb filtering and so on.
I'd have to say that very few subs (subwoofers) are chosen and set up properly because many do not know how to do it or do not realise how important it is. If the subs are not set up properly they introduce more problems then they cure. You get issues with improper bass level, poor crossover and therefore poor balance, timing innaccuracy, phase and reflection issues and so on.
Pro studios often use big 3 way monitors partly to avoid the issues with subs and partly to try and deliver a better, more accurate low end. A big, 3 way allows for a larger (i.e. 7inch or bigger) bass speaker that is better integrated with a dedicated mid range and high end speakers, along with dedicated power amps that drive each speaker individually. Reflection, timing and phase can be better controlled as the system is deisgned for it. The bass speaker can have a lower roll off at a lower point, the size of the speaker also means it can physically move more air without unwanted distortion and so on.
Personally, although NS10s were used widely in mix studios for many years I'd avoid them if you want anything close to flat. They very definately are not flat and I'd go so far as to say that the high mid is problematic and that there is very little bass end below 90Hz. To use them with any degree of confidence you would have to spend a lot of time getting used to their sound. They were used in a lot of mix studios because they were good for their time at their price point but monitor design has moved on quite a bt since then. There's loads available used but some have been hammered in studios and so not at their optimum anyway and may need refurbishing quite quickly. Whilst many are in good condition you really need to audition them properly, don't buy without hearing them first.
If you want reasonable (i.e. not as expensive as mastering ones) active monitors designed for tracking/mixing at an ok price then as Ivan says Tannoy Reveal. I'd also add Adam A7, K&H/Neumann100, Genelec (can't remember the model numbers - think its 8030 or 8040/8050), Focal 6 or opal, JBL LSRs, Mackie HR826 (cheaper option is the 624), Dynaaudio BM5/6...
With the use of multiple monitors in studios... A bit like Ivan my experience is that pro studios often have an ok small pair and another bigger 3 way set. Bigger 3 ways often have to be driven quite hard to produce their best: that usually means a much higher SPL at 1 meter and in a a mix studio environment where the monitor is very close to where you sit that also means that you get high volume and high SPL, which can be fatiguing and potentially damage your hearing over extended time periods. Pro studios nonetheless often have big 3 ways as they reproduce the bass etc better and can go to higher volumes without distortion etc than 2 way and as Ivan says they often use them to check a mix.
Some mix studios have several 2 way pairs that are in different price(i.e.1 over 1000USD and 1 under 400) ranges to check translation. Very few pro mix studios have multiple sets of 2 way that are all in the same price range as many believe that in general if you routinely compare a mix as you do it on similarly priced monitors its an indication of a lack of experience/confidence with the monitors. That's a generalised opinion of course and certainly isn't true of all those who do use several sets of similar 2 ways.
In a mastering studio because we sit much further back (usually 2-4 meters away) and so can drive them as intended with less chance of fatigue and hearing issues. Most mastering studios only use a single set of 3 ways and we do translation checks elsewhere (having multiple monitors in a room causes its own issues with comb filtering, resonance and so on).
With smaller, less expensive studio monitors you will not reproduce the bass end without adding subs and all the issues that that entails. However if you can only have a small 2 waya sub may be the only way that you can reproduce a low end. If that is the case you'd need to decide if hearing the low end is more important than potential issues with a sub. If you get a sub then make sure that it is properly installed and integrated.
Regardless of what you do you need to run the monitors in - i.e. play music through them for an extended period. The cones etc need to 'loosen up' before they deliver their best consistently and this can mean several hundred hours of use at moderate, and some at highish, volume. You also need to get used to them and how they reproduce the audio in your studio with your monitoring chain: so you need to listen to a lot of pre-recorded music that you know well. That way you can get used to how they present audio and what their idiosyncracies etc are.
What's a flat response?
A flat response from a speaker would mean that it is capable of producing a spectrum across its range from 0-20kHz that showed no attenation or gain of the original signal. So if you took a tone generator, set it to produce a simple sinewave and swept it across the frequency range 0-20k with no change in amplitude and then measured the output of your speakers on a spectrum analyser you should seea horizontal straight line.
That doesn't happen in reality as speakers can't meet this ideal. All speakers roll of the bass and very high end. The more they do so the further from flat they are. Every drop of 6dB is the same as halving the volume for that frequency: so a monitor that starts to roll off at 80Hz and does so at say -6dB per octave (similar to many mix studio 2 ways) will produce significantly less bass than one that rolls off at 50Hz and does so at -2dB per octave (similar to a 3 way mastering monitor). The far ends of the spectrum are not the only issue though as mix studio monitors and hifi speakers are deliberately voiced to sound 'musical' rather than accurate. This often means that they will add some gain and attenuation to the signal at differeing points in the spectrum. Many deliberately add some gain around 80-100 on a narrow Q to blur/mask the bass roll off a little. Many add gain in the mid band to add presence to the mid range around 1-5kHz. Some speakers have issues with cross over and so you can have dips and peaks at the cross over bands. Many don't have properly matched amps driving the separate speakers so you end up with shifts in balance and attenuation. Exactly what a monitor's spectrum looks like depends on how the manufacturer wants to voice their monitor and what issues/deficiencies they are trying to deal with: they are not flat though.
It's also worth noting that most manufacturers produce a frequency spectrum plot for their monitors that you can look at and compare. If they do it's worth a look but as wiith all of these type of things you need to be careful: 1/ lies, damned lies and statistics: many do not state the test conditions, how measurement was conducted and what weightings were used. Many give no indication of the vertical scale so you do not know how far up the axis + 6 dB is and consequently don't really know how 'flat' the line is. Very few give information on timing, phase and other issues. Even if they supply all the data it doesn't really tell you how they sound and whether you like them- you need to hear them.
It's just the same as if you were buying a guitar or amp. The best thing is to test a pair in your actual studio and so hear it properly in situ. If you can't do that then you should try and have an extended trial in the shop. Just buying blind without hearing them is risky.