Klaus Heinz: How To Find The Better Studio-Monitor
To find the better sounding monitors is a vital question for most of the music producers, recording musicians and their sound engineers. I fear not only the answer is difficult, the question itself already bears the problematic expression ‘better’– better in which respect, and better for whom? When talking about Audio it is advisable to differentiate between the subjective and the objective domain. It is one thing to do measurements and discuss their meaning, and it is quite another thing to draw conclusions about the sound or the sound quality from any acoustical or electrical speaker measurements.
There are many measurement values and curves you can get from a monitor today. The power of the FFT – Fast Fourier Transformation and some related mathematical operations allow to view measured data in either the time or the frequency domain in various ways. Many different stimuli can be used like sine sweeps, short (so called) Dirac pulses, Multisinuses or noise with different spectra, and all of these allow to study the response behaviour of a loudspeaker to some detail. Additionally, out of one impulse response – that can be calculated from all the mentioned signals above – one can generate CDS Cumulated Decay Spectra or 3D waterfall plots that observe the way the speaker settles after being switched off, the directivity behaviour or simply the frequency and phase response. Furthermore, different kinds of distortion can be measured, be it the classical THD (Total Harmonic Distortion), that indicates the amount of overtones added by the speaker, or the IM intermodulation distortion that calculates the amount of differential tones caused by the device under test. All this is possible without the need for an anechoic room, something that makes things much easier. More complex techniques that go beyond linear measurement / FFT applications like wavelet analysis or Wigner diagrams are an additional choice to learn about a speaker’s behavior in the objective domain.
“The real sound field and its perception are dramatically more complex than any single or set of acoustical measurement(s).”
The most common measurement of course is the frequency response. Look at the two frequency measurements posted below, a B&W speaker from 1984 and a current HEDD Type 30: besides the fact that the B&W quits service above 15 kHz, there is no progress to be seen. A linear speaker is a linear speaker. Is a linear speaker. Yet nobody can deny that there is great progress in the reproduction quality of modern monitors. The conclusion has to be: a linear frequency does not imply superior sound quality!
Linear frequency responses have been around for a long time. As impressive as they look: The won’t tell you much about the actual sound quality of a monitor.
That being said, to measure is a valuable and indispensable tool for the designer to verify the quality of particular components and to not make mistakes in the overall complex transferfunction. To communicate measurements to the end user is also indispensable as they need to know that the design of the unit (if the measured data is fine) is free of bugs. But that`s pretty much all.
Let me illustrate you in a small description how difficult a reliable monitor comparison can become:
Situation 1: you compare monitor A and B, prefer A, then you listen to another file and: prefer B.
Situation 2: you do the same thing and change speaker positions: the better bass response that A had produced so evidently now comes from B. It was the positioning within the room that fooled you.
Situation 3: You do the same sequence, but have moved to another room – things might look the other way around.
Situation 4: an experienced colleague is with you, you have to accept that he does not agree with you in the one configuration and shares your opinion in another.
Situation 5: Should you do all this with 3 monitors and 3 other sound engineers the situation gets drastically more complicated.
Comparing monitors can be a hassle. But doing it correctly will give you a much better understanding of a monitor’s quality and eventually help to shape your opinion. (Photo: Emil Berliner Studios, Berlin)
“Putting some serious effort into getting your room acoustic right, will make a major difference when it comes to judging the quality of a pair of loudspeakers.”
If you would apply normal probability calculations to these different sessions it would be nearly impossible to come up with a solid and reliable judgement. It gets better if one can involve experienced listeners – a rare species by the way. And it goes without saying, that putting some effort into getting your room acoustic right will make an important difference when it comes to judging the quality of a pair of loudspeakers.
First of all, a great monitor retains much of the dynamic of a source. When you compare a compact to a let us say 2x 12” monitor, you will immediately hear that this is a job that is easier handled by bigger speakers. Great monitors also offer a stable and transparent sound even when pushed hard (as well as when pushed only a little!). Additionally it lets you observe the different spatial layers in your audio material. This is very important as todays composers and audio producers can choose from an almost infinite number of good and bad reverb- or spatialization-plugins. The better the monitor, the easier it is to shape the details and spatial layers of a mix or a recording. If your room allows for a bigger speaker, you will also be able to cover a wider frequency range and enjoy an increased dynamic headroom. As a consequence you don’t have to rely too much on headphones and/or subwoofers.
At the end of the day, another thing is true: self-powered „active“ monitors can be considered the better solution for audio production because all the components in a speaker such as the cabinet, woofer, tweeter and electronics are designed with a specific amplification system in mind. The direct coupling of the drivers to amplifier output leads to a better amplifier control. And last but not least, you avoid the various limitations of passive crossover components.
“If you really care about the quality of music reproduction you need to listen and decide for yourself what you consider to be the more realistic reproduction – that is what “better” should mean for the critical sound engineer.”
To observe a few rules whilst comparing monitors may be helpful to not to fool your ears:
- Position: place the different monitors equidistant – not symmetrical to the middle – and close to each other.
- Level: pay careful attention to the subjective listening levels. Due to differences in the frequency response this may even differ from track to track, so it might become necessary to readjust the gain of one of the pairs to always compare them at the same subjective loudness. It is astounding how trappy a dB more in SPL translates into comments like “more dynamical speaker”, “better transient response”, “wider stereo image”, etc. After decades of designing – and of course comparing – studio monitors I have to confess that I still can become a victim of these effects at times – but I do get up and regain the louder pair when I detect an imbalance, always.
- Music: Consider listening to acoustical recordings with natural instruments and voices. One of the main aims should be to judge how authentic the recordings sound, not to be impressed by the most powerful bass response. In many cases, where a speaker delivers a “mighty” low end, it turns out that for example an acoustical Double Bass sounds mighty too – although in reality this is not the case. A monitor is supposed to give you a clear view into your work, not exaggerate particular frequency areas (even though listening to speakers that deliver room-shaking low frequencies can be fun).
- Flat filters: Make sure that all filters in the speakers are set to flat response, at least in the beginning. This will reveal the intended character of the speaker. If you repeatedly have the impression that a certain monitor sounds too bright for example – apply a shelf filter, and repeat the listening test with the same tracks.
- Recordings: Try to listen to a few known recordings too – not because “known” means better, but because minimizing unknown parameters in a comparative listening test usually helps to focus on the evaluation. Excellent recordings will help you reveal quality differences much better than smeared or extra-sharp mixes.
Finding the right monitor can be a big, but very rewarding hassle. Positive opinions about certain monitors in private discussions, blogs and Pro Audio magazines are an important indicator for a product’s quality – but certainly never a proof. They should never replace your own listening experience. If you really care about the quality of music reproduction you need to listen and decide for yourself what you consider to be the more realistic reproduction – that is what “better” should mean for the critical sound engineer.
Klaus Heinz is one of the most experienced loudspeaker designers in the world. He is the founder and long-term Managing Director of ADAM Audio. In late 2015, he launched HEDD | Heinz Electrodynamic Designs.