Comparison of microphones - Small and large diaphragm condensers

The first thing that comes to mind, finding myself in the presence of "affordable" brands like Joemeek, is that this technology, with its high price / quality ratio, can have the power to make users with great taste and potential but on a budget realize limited, products that can give a foretaste of the emotion of great artistic quality.

Let's not forget that an important thought, a literary work can also be written with a ballpoint pen, without diminishing the thickness of the work itself. It is clear that in any type of production the ideal coexistence is that of aesthetics and content, but this shouldn't make us feel frustrated if we lack economic possibilities; the important thing is to have tools, even if they are not of high caliber, which allow us to remain in a sufficient and acceptable technical standard that does not distort our expression. It is no coincidence that we are talking about Joemeek. This is a brand that produces tools that are certainly up to the task and that, thanks to skilled hands and ears, can help produce a master also worthy of an easily marketable professional moulding.

Audio chain

For this test the two microphones were connected via a mogami cable, first to a solid stage mic preamp  Millennium model HV - 3D (Fig.1) and then to a tube PRE with a very enveloping sound typical of the 70s, the 2 - 610 of Universal Audio (Fig.2). The outputs were connected directly to a sound card RME Fireface 800  with resolution 24 bit / 192 KHz  and monitored by two pairs of speakers, the PMC model TB2S-A with 6-inch cone for a standard close-up listening and as a final listening, to have a better response in the low frequency range I borrowed the Genelec 1032 with 10-inch cone, excellent for this type of tests, but completely unsuitable for “near field” use as to work at the right speed they must deliver a fairly high signal.

JM 27 as it looks

The JM 27 is presented in a simple cardboard box together with the joint for fixing the rod, the guarantee and a small manual in English (Fig 3). It is a stylus microphone, cardioid polarity with "True Condenser" technology, the small diaphragm is in "mylar" covered with evaporated gold with a diameter of 20 ml and thickness from 6 microns. The internal preamp circuit is technology based  Fet and the transformer balances the audio signal. Externally the microphone has a satin surface with a good smooth and glossy finish. The capsule is threaded onto the microphone body and has a good impression of solidity. There are no setting controls on the microphone, like HP filter e attenuation pad, specifications require precise phantom power a 48 volt.

JM 27 Under the press

In the "road test" our microphone was carefully subjected to a series of tests carried out on various instruments, the voices were excluded from these tests, for the simple fact that I do not like to record them with small diaphragm microphones and not at all. I feel certain to recommend them. For the recovery of vocals in general, large diaphragm microphones are certainly much more suitable, giving the voice an airy and seductive tone.

Guitars

The feeling you get when listening to the general timbre taken is that it seems to be dealing with a large diaphragm microphone. The JM 27 did not turn out beautiful on the classical guitar already medium in itself, on the contrary on the acoustic, iron strings, it proposes smooth and never harsh highs, penetrating mids and sufficiently defined lows. However, it lacks that airiness, crystallinity and sense of the environment. But this is a microphone that makes its character felt markedly: it is to be loved or hated. Even for the electric guitar amp it can be extremely exciting providing a truly remarkable image and dimension. In my opinion it is beautiful and useful in all those pieces where the arrangement is based on a few instruments and it is in this case that the size of the sounds used should be considerably present. On clean and distorted sounds, the microphone has a rock soul always aimed at enhancing dimension and presence, even at the expense of refinement. Let's face it all: in certain genres transparency is not sought at all, on the contrary, non-linearity can even become a peculiar aspect of the arrangement.

Over head

As a microphone over the drums it can be quite interesting. In the test he returned present and full-bodied drums almost as if they had been taken in "close mixing" while the cymbals including the "hai hat" (hi-hat) were not returned beautiful and silky, but on the other hand with a decent attack without ever being predominant and annoying. Proof then passed brilliantly and also in this case providing a good dose of character.

Violin

Even if the use of the single violin is not widespread in all contemporary musical genres, this is an instrument of great history. Furthermore, the mysteries not yet hidden on the construction techniques of Cremonese luthiers such as Stradivari and Guarnieri continue to create an aura of charm and mystery around this instrument that even I have not been able to resist. The violin (Fig.4) is really unhappy to resume and, assuming that the instrument used for this test is of excellent lutherie, including the bow, and that the violinist is technically and passionately gifted, we immediately say that the microphone placed at about 35 cm in the direction of the harmonic plane near the bridge has proved surprisingly effective, returning a timbre of considerable size with not at all harsh highs (3000Hz-4000Hz) with penetrating mediums (800Hz –1500Hz) to defined bass, round and warm (250Hz-300Hz). Undoubtedly, also in this case little sensitivity towards the environment and therefore little air around, but this microphone really manages to produce that type of recovery that serves to bring a sound into the foreground within a mix and this also for the violin that apart from its undisputed charm, it is truly a difficult instrument to place when not playing in a section.

Conclusions

To get good results it would be advisable to connect the JM 27 to an excellent pre amp. Very fast and linear solid state mic like "transformless" ones without output transformer type 2108 Universal Audio, Millennia HV3 in order to be able to provide a just completion since this microphone is already colored enough to avoid tonal excesses at the limit of the dough. Once connected the JM 27 you immediately receive a great surprise: usually this type of microphone always returns a clear, defined and detailed timbre, in particular on the mid and high frequencies section always linked to a sense of naturalness and with a excellent transient response. The Joemeek, on the other hand, appears to be characterized by a clearly British mediumness and an image that is not at all small and rarefied with a very strong and non-linear personality. I don't think this character always corresponds to a defect but it is clear that we must choose it whenever we need it, not to mention its splendid value for money. I am pleased that in such a low-end microphone, the evaporated gold coating technique has been used on one of the membranes, in this way we avoid that high pressure levels cause the membrane to collide against the polarization armature. It was really a pity that once again I did not have a selected pair of this microphone available in order to better analyze the ability to return the stereo image together with the separation of the sources, this being a directional microphone. Happy registration to all.

JM- 47 What it looks like

It's a large diaphragm microphone, (Fig.5) precisely from the standard diameter from 1 "  in mylar covered also in this case with evaporated gold. The polarity is the cardioid one with condenser technology. The internal preamplifier circuit is based on Fet and the transformer balances the audio signal. The 48 V phantom power is required for operation. The instrument is delivered in a simple cardboard box together with the metal joint for fixing the rod and the windproof cap. Externally its discreet cylindrical body is beautifully finished with a smooth satin surface. The capsule is fixed to the rest of the body and at the base of the body there is a ring for a possible disassembly of the microphone. On the body with switch control there is an attenuation pad from 0 to - 10 dB and a high pass filter whose frequency value is not stated in the manual. Remember that the right side for shooting is the one where the logo is located.

Male voices

With the serious intention of wanting to do a good, meticulous and diversified rehearsal, I invited two male and two female voices of different gender and attitude. The first male voice for the rehearsal moves between the baritone and tenor register with airy and persuasive expressiveness. The microphone placed at 10 cm returned averages around 2000 Hz quite evident, little air around and basses that are not enveloping but controlled with excellent management of the proximity effect. Effective, but not preferable in this vocal situation, the same opinion is also the singer. The second male voice moves between the mezzo baritone and the tenor with a markedly rock-like tone shot and rough around the 3000 Hz. Placing the microphone at the same distance, it immediately proved to be the ideal partner for this type of voice and musical genre. Without a shadow of a doubt it shows all its British character, middle mids capable of piercing any mix. It certainly does not have the class of a Neumann but in terms of timbre decision it has something to sell. Although in this case it also maintains a good management of the proximity effect, an anti pop screen is still recommended, not so much for controlling the energy on the low frequencies, but to better smooth the high frequencies around 9000 Hz, area of ​​residence of the annoying "S".

Alto voice

The female voice available has an enviously warm and harmonic characteristic that is almost masculine at times. Our microphone in this case is exalted to the great, doing justice to the objective of the performance characterized by great energy with a pleasant bluesy vein, returning that pinch of nastiness with excellent speed to transients without a minimum of distortion, even without "switching" the attenuation pad on the body of the microphone let alone the HP filter, remembering that this microphone has an excellent control of the energy on the low frequencies showing little sensitivity below 70 Hz as if it were already filtered.

Soprano voice

The last rehearsal is on a soprano voice with a lyrical setting. In this case it was mandatory to insert the attenuation pad. The treble of this formidable singer possesses crazy energy, which is why the distance has also been increased by another ten centimeters. I must say that it is not preferable in this situation to use the JM 47 because the acoustic response that comes out is not very harmonic, dry and sometimes annoying. It would be advisable to film this type of voice and performance in a more suitable place, such as an auditorium or a church with an average reverberation, with an omnidirectional polar figure microphone placed one meter from the sound source.

Guitar

Place a 30 cm from the electric guitar amplifier the microphone reproduces exactly the same sound that comes out naturally from the amp, that is, full-bodied, intelligible with excellent middle mids. In this case, the attenuation pad must be inserted because the overall volume of the amplifier has been set with high power. On the acoustic guitar with iron strings the JM 47 has exalted itself more in solos than in accompaniments, always showing a certain attitude towards rock for its response to the middle mids. Give it 800Hz to 3000Hz always ready and penetrating.

Congas

Microphone placed a 50 cm in height above a couple of congas the Jm 47 returned a nice response rich in attack and depth. The rubbing of the skin over the instrument was clearly heard creating a truly suggestive atmosphere, thanks also to the skill of the excellent original Cuban musician. Even the slap was reproduced with a good attack and freshness reconfirming its predilection for central frequencies, always returning speed, intelligibility and naturalness. The low section of these drums was not reproduced in an irresistible way, giving back little presence, precisely by 200 to 500 Hz, it would be advisable to bring the microphone closer which, being directional, would allow to exploit the proximity effect to gain energy on the low frequencies.

Conclusions JM 47

The JM 47 also demonstrates character to sell with a deliberately filtered tone on the low, medium present and never exasperated highs. In general we can define it in line with the English school. Undoubtedly it was designed for those users with small budgets such as those of home and project studios. As for the aesthetic judgment, let's say right away that it could easily deceive its economically affordable nature, this due to its good finishes and details worthy of much more expensive microphones. Also in this case the judgment is more than positive. Electronically it is an instrument, as well as the small JM 27, really suitable for cleanliness and sensitivity to modern recordings, it could even become a privileged choice in all those rock productions. Let's not forget that the microphone for everything does not exist.

General conclusions

This is an almost impossible type of comparison precisely for the two different types of microphone. Even if the same construction technique is used, the diaphragms are of different sizes. This already establishes electronically different reactions and therefore also in the application phase. Among the many myths surrounding the world of microphones, one is the difference between large and small apertures (Fig 6) and the impact these have on registration; one day you record an acoustic guitar, the next day you pick up a snare drum up close. Choosing the right microphone for such diverse applications plays an important role in a technician's job. But what are the pros and cons of different sized diaphragms? How do you find the solution that best suits your needs? The brief general description that follows should help you with this choice.

Background noise

The background noise of a microphone depends on the size of the diaphragm and how stiff or compliant it is. The choice of material has a great influence on the compliance of the diaphragm itself and therefore on the intrinsic noise of the microphone. In general, small diaphragm microphones have higher background noise than large diaphragm microphones.

Sensitivity

The sensitivity of a large diaphragm microphone is greater than that of a small diaphragm microphone, as the larger one is compliant and easier to move. In addition, the low output level produced by a small diaphragm requires more amplification, which adds electronic noise to the signal.

Ability to manage the sound pressure level (SPL):

The ability to handle the SPL of a microphone is limited by both the distance between the diaphragm and the plate behind it and the stiffness of the diaphragm. These factors establish the limits of possible diaphragm movement before distortion gets too high. A smaller, more rigid diaphragm is therefore able to handle higher sound pressure levels than a larger, softer diaphragm.

Frequency response

The lower frequency limit of a pressure microphone is determined by the size of a small vent, which prevents the diaphragm from moving in response to changes in ambient static pressure. Therefore microphones with large or small diaphragms are, in principle, equally capable of handling low frequencies. The upper frequency limit, on the other hand, depends on several factors. First, at high frequencies, a large diaphragm tends to "break down" and no longer act like a real plunger. Second, the weight of the diaphragm attenuates its shift at high frequencies. Third, diffractions around the edges of the microphone capsule limit the capabilities of the microphone at high frequencies. A microphone with a large diaphragm therefore has less bandwidth than a microphone with a small diaphragm.

Characteristics of directionality

All microphones become progressively more directional at high frequencies. The size of the diaphragm determines at what frequency directionality begins to occur. This is because the sound coming from the front of the microphone creates an increase in pressure and diffractions in front of the diaphragm. This occurs when the wavelength of the frequency is comparable to or smaller than the size of the diaphragm. Therefore the smaller the aperture, the smaller the effect and the greater the omnidirectionality.

Dynamic range

The dynamic range of a microphone is the difference expressed in dB between the background noise and the sound pressure level reached, following which the microphone exhibits a certain amount of Total Harmonic Distortion (THD).
As described above, the background noise of a microphone grows if the diaphragm is small, but the handling capacity of the Spl grows even more. Small diaphragm microphones may, therefore, have equal or better dynamic range than large diaphragm microphones. The dynamic range is simply shifted to cover different ranges of sound pressure levels.

I really hope I have provided you with valid help and dispelled any doubts for a possible choice perhaps between these two microphones just reviewed.

Until next time.

Antonio Campeglia

Personal advice from Antonio Campeglia

I remind you, however, that the body of any instrument is useful to keep it full in a "mixdown" where the arrangement revolves around a few instruments, while in a crowded mix it is necessary to create the right timbre dimensions and positioning in the stereo landscape for a good coexistence. and intelligibility.

Try last now

This test was done a few hours before delivering the article to the editorial office, I wanted to transcribe it as I found it very interesting. In the morning, when I was working in a shop in Naples, while I was talking to a person, a percussionist called me asking for help to try out how his filter sounded. MF 102 (Fig.7) Of the Moog on some percussion he wanted to buy. I quickly mount a microphone for him AKG C 451 B with phantom power on the filter (in this case between the microphone and the Moog I put a pre with phantom) I position the rod with the transducer on the Groin, a Caribbean percussive instrument, I look for the right distance, amplify everything with a Yamaha system and listen to what happens. The Hang has a major pentatonic tuning and at the base it has a beautiful bright color, atmosphere, very silky and engaging. Filtered through Moog, it acquired a sound that was too emphasized on the highs. Even playing on the frequency of the modulation and the rate of the LFO, I could not pull anything interesting. The percussionist at this point thought that perhaps the Hang was certainly not the best instrument to use live and turned to a Balafon (Fig.8). Let's try this instrument together and also in this case the sonority did not impress us, it certainly proved more interesting than the previous instrument, but nothing particular. Having the JM 27 with me, I asked the musician to play me the two instruments using my microphone. Also in this case I tried to find an ideal position to have a good control of the dry and effect sound and… miracle! With a microphone of a lower price range the result is completely different, the filtered instrument takes on a really interesting sound and it is even possible to have a very varied color palette using the few parameters of the Moog. Instead, in the second instrument, which is much darker at the base, it seemed to play a series of differently tuned drums. I wrote this experience not to exalt the microphone or tell you that it is better than the Akg, but only to advise all readers to always experiment and not stop at the basics that any "Guru" in the field can give you. In this case the slightly medium sound that a Fet generates was very useful for this type of application, while a more open one like that of the C 451 B has not proved suitable for this use.

USEFUL INFORMATION:

Producer: JoemeeK
Model: JM27
Website:www.joemeek.com
Distributor: www.feel.it
Price: Euro 110 + VAT

Producer: Joemeek.
Model: JM47
Website: www.joemeek.com
Distributor: www.feel.it

Price: Euro 254 + VAT

Technical characteristics JM 27

Frequency response: 30HZ- 20KHz
Sensitivity: 10mV / Pa-40 +/- 2dB (0dB = 1V / Pa 1000Hz)
Polar diagram: Cardioid Diversity> 12dB (300-3000Hz) b Diversity> 15dB (1000Hz)
Impedance: 200 ohms
Signal to noise ratio level: 18dB (weighted in class A)
Max SPL for 0.5% THD @ 1000Hz: 130db
Power supply: 48V phantom power

Technical characteristics JM 47

Dimensions: 137X22mm
Frequency response: 20Hz to 20KHz
Sensitivity: -36dBV approx
Impedance: 2Kohm
Signal to noise ratio: 74dB
Dynamic extension: 126dB