Friday, 13 January 2017

Technical: Practical Tips on Minimising Feedback and Maximising Gain. Part Three.


Practical Tips for Taming the 'howl'. Minimising feedback and maximising the music. 

In part one we took a look at what feedback actually is, what causes it, and how it takes place at different frequencies. 

In part two we took a look at physical measures we could employ to minimise feedback and maximise gain. Loudspeaker and microphone positioning, etc.

In this part,  we are going to take a close look at how equalisers (or EQ's) can be employed to fight the dreaded howl. Graphic and parametric EQs are often employed to EQ sound systems although they are by no means the only devices that can be used. Graphic EQs are the most popular and important devices for couple of reasons. Firstly using practical examples of implementing graphic EQ's we learn about the nature of feedback and it's occurrence at particular frequencies/wavelengths, and secondly digital versions of graphic EQ's are now found in abundance in the latest digital mixing consoles and loudspeaker processors. So what we learn by using a traditional analog graphic EQ can be applied to the latest digital consoles and processors. Parametric EQ's can also be used and, once again, most digital devices offer parametric EQ options.  

The first item we'll take a look at is the traditional analog graphic EQ. Although this type of device may be considered slightly 'old fashioned', digital versions of graphic equalizers are often to be found in the latest digital mixing consoles and loudspeaker processors. I think the analog graphic EQ is a great place to start, because it illustrates the fundamentals. What we can learn from an analog graphic EQ can be applied to the other devices that employ digital versions. 


2 x 30 Band Graphc EQ


'Ringing Out' a Front-of-House PA Using a Graphic EQ.


The process used to EQ a sound system for minimal feedback is called 'ringing out'. Since this is a 'practical' guide to minimising feedback, we'll use this is a  process as not only is it extremely effective, but it also teaches us about the nature of feedback. More comprehensive processes are available. Using pink and white noise in conjunction with real time analysers to measure room response and then applying EQ curves is a more 'scientific' and effective way of carrying out room EQ, which is great for venues and system installs where the time and equipment is available. But from a practical musicians perspective, ringing a system out using the lead vocal mic channel can deliver excellent results, fairly quickly, and with quite basic equipment.  

'Ringing out' involves repeatedly advancing the gain of a channel (usually the lead vocal mic channel) which induces feedback at a particular frequency, and then using the graphic EQ to remove the 'ringing', then repeating the process.
Of course, we need to have our sound system setup properly in the first place in terms of gain structure and phase. You can check out my post on gain structure here

I would generally ring the system out between completing the setup and the soundcheck, so I would suggest getting your system setup with a graphic EQ in line with the master outputs of your mixing console, or via the master insert points. At this point, you really only need the lead vocal mic, so if your engineering a band that hasn't arrived yet, just setup a lead vocal mic in it's usual position. If the band arrives with you, then you can carry out the ringing out between setting everything up and the soundcheck. You may want to play some music to check everything is working.

On the mixing console, I would suggest starting with a flat channel EQ, set the gain control at the top of the channel to it's usual position (this will depend on the mic and how loud the singer is) so it delivers a healthy signal without clipping. A few 'one two's' down the mic channel might be useful for this. The channel fader at the bottom, Set the master fader(s) at unity, or '0' on their scale (usually about two thirds of the way up). Set the graphic EQ to unity input/output gain with all the faders in the middle detented position. If you have a choice of 6db, or 12db cut/boost, I would suggest setting it to 12db. 

Since most live sound systems tend to be stereo, and therefore a stereo graphic EQ will be employed, you can 'ring out' each side separately. Since rooms are rarely completely symmetrical this will give you better results and ringing out both sides simultaneously may get rather confusing in terms of which side is actually feeding back, etc. So I would pan the channel left, carry out the ringing out procedure, reset the fader to the bottom, then pan right and carry out the ringing out procedure for the right side.

So with the channel panned left,  open the lead vocal channel and slowly bring up the fader. As you advance the fader at some point you will reach your first 'ringing' point. This will be at either a low, mid, or high frequency. Identify the frequency that is ringing and bring the corresponding fader on the graphic EQ down 3db. It will take some practice to identify the frequncy of the ringing. If you bring down the fader on the EQ and nothing happens, then you've identified the wrong frequency. Replace that frequency back to the centre position and try adjacent faders. Once you've selected the correct frequency centre the ringing will stop. Then we repeat the process. Advance the channel fader on the mixing console some more until you hear more ringing. Identify the frequency and bring down the corresponding fader on the graphic EQ by three db. Keep repeating the process until you can't squeeze anymore gain out of the system. Then repeat the process for the right side. 


Notes On Graphic EQ Types:

For the purposes of system EQ, graphic equalisers with more bands are preferred. So 30 or 31 band graphics are the best type to employ. The reason for this is that the each fader on a 2x 31 band graphic EQ covers less bandwidth than those on, for example, a 2 x 15 band graphic. In other words, the filters are narrower. This means that when removing frequencies that are feeding back, or ringing, we can do so with minimal effect on adjacent frequencies. It's more accurate. 


Graphic EQ's and Digital Mixing Consoles:

Of course, exactly the same processes can be applied to the graphic EQ facilities found on digital mixing consoles. These consoles typically have some form of digital EQ for every output. Often a choice of parametric or graphic type can be selected if not both. Of course the use of such systems is rather different. The parameters will now have to be controlled by a menu and screen. Sometimes touch screens allow you to select the frequency and apply cut/boost. Some digital consoles allow you to 'map' the cut and boost faders of the graphic EQ across the physical mixer faders. In many ways, analog graphics tend to be more immediate in this respect, just reach out and grab the appropriate control. Mastering the control of the EQ parameters on a digital console may be more convoluted and slower at first, but with practice and a knowledge of your product, they can be learnt, and exactly the same processes as those of an analog mixer/EQ combination can be applied.   


Monitor Systems:

Much of what we've learnt and practiced so far can be applied to monitor systems. In fact given the proximity of microphones to monitor speakers on a stage, correct EQing of monitor channels is even more important in order to achieve useful levels from stage monitors and 'wedges'. 
Most monitor output sends will generally be EQ'd somehow whether the monitors are run from the front-of-house desk or via a dedicated monitor mixer. Usually each send goes through a graphic EQ. This is why you'll see lots of graphic EQ's racked up next to monitor consoles in larger systems. 
Things can get rather complicated here, since there may be several microphones in proximity to each stage monitor. I think here, we can apply the same logic as for front of house systems and select the most important microphone and EQ the monitor to that. So, for example, a lead singer will generally want to more of him or herself in their monitor wedge/s so they can accurately pitch. It's not all ego with singers! So I would suggest EQing/ringing out the wedge using their microphone. Naturally they will also want to hear a mix of the rest of the band, but these instruments and associated mics will be positioned further away and probably require less gain in the the monitor than the vocalist. 
Backing vocalists may share wedge monitors. This may be due to budget considerations or the available number of sends on a mixing console. Here, I would suggest, if possible, using same microphone types, and ring out using the one situated closest, although you may get into an argument over whether microphone selection is an 'engineering' or 'artistic' decision. 
Drums present a unique problem. Drummers will generally want to hear plenty of themselves on their wedge monitor, particularly kick, snare, and hat, but also very usually the toms as well. All the mics situated on a drum kit will have wildly varying frequency responses and pickup patterns so it will be difficult to EQ or ring out the monitor to a particular microphone. This may be further complicated by the fact that the drummer may also sing, (although in many ways this might make the decision easier. He or she will probably want lots of vocal in their monitor, so EQ to the vocal mic). Here, I would suggest a couple of solutions. Gates are an excellent solution when it comes to minimising feedback from drum microphones. Although usually employed artistically to achieve a certain type of sound, the fact that the mic is only open for a very short time reduces the possibility of the onset of feedback. So lots of gates used on the channel inputs of the drum mics can be useful if you have the budget, although, again, most digital consoles offer a gate for every microphone input channel although there may also be artistic considerations. More on gates in the next part, part four. Secondly, you could employ the graphic EQ to make changes 'on the fly'. If you find the drum wedge ringing during the sound check you could make the necessary adjustment to the graphic 'on the fly' although this may take some practice and experience.  

Parametric EQ's:

Parametric EQs aim to achieve the same basic result as graphic EQ's i.e. tailoring a signals frequency response to match room reflections and microphone and loudspeaker responses. Parametric EQ's have fewer 'bands' typical four to six compared to up to 31 for a graphic EQ, but parametric EQs allow you to adjust the frequency and width of each filter. 


Stereo Parametric EQ

So here, we can set the cut/boost control of each filter to -3db, then as we hear each ringing frequency we can sweep the frequency centre of the filter up or down to find the offending ringing frequency. Which should then disappear. Bring the fader up some more and repeat the process for the second filter, etc. The obvious benefits of the parametric are if you're not very good at frequency detection, you can just seep the filter up or down and it will eventually cross the problem frequency and remove it. 
Generally speaking, I think graphic EQ's tend to be used for response EQing in PA and monitor systems. They offer more filters and, I think, can squeeze out more gain than a 4-6 band parametric. It's now quite unusual to see parametric EQs employed for this application although they can be quite effective, so if you've got one lying around......
Parametrics, I think, are more effective for what I would call 'artistic' or 'tone control' EQ for individual instrument. To produce a more 'pleasing' sound. 

Empty Rooms versus Full Houses:

I guess at this point we should say something about empty spaces (during setup, system EQ and soundchecks, etc) and changes that occur once the doors open. I think the thing to say here really is that whilst our process of 'ringing out' in a near empty room may not be scientifically very accurate, in nine out of ten situations, things generally improve when the audience arrives. Audience members 'soak up' room reflections, an also usually the room becomes warmer which is generally beneficial to the propagation of sound waves. On the downside, background noise will increase, meaning things may need to get a little louder. So, although the different room situations are a factor, the ringing out process is still very worthwhile and carrying out system EQ after the audience has arrived is not a practical proposition. Of course having a properly EQd system will aid enormously for the soundcheck, in terms of achieving an excellent mix and sound balance, and in turn helping musicians, promoters, venue owners etc. feel confident about the whole event. You will usually find your faders will go further north before feedback in a full/warm room than in a cold/empty one.


Conclusion:

So 'ringing out' PA and monitor systems is an essential part of any successful sounding live music gig. EQing these systems will deliver much more system headroom, usually around 6db, and make the 'artistic' side of mixing the band much easier and produce much better results. You'll be able to make adjustment to your mix without the onset of feedback, and adjustment to 'artistic' EQing via the mixing consoles channel EQ. 
Indeed, the distinction between 'artistic' EQ i.e. making a voice or an instrument sound 'pleasing' ,or as it should sound (usually via the mixing consoles channel EQ), versus 'engineering', or system  EQ which is what we've been dealing with here, is an interesting one. Get the system EQ right and you'll have  much more headroom for your artistic decisions. For example, you'll be able to add more 'top end' sparkle to that acoustic guitar without worrying about reaching the point of feedback. 


In part four we'll take a look at other devices used for combating feedback and increasing system gain including dedicated feedback 'destroyers', digital loudspeaker processors, real time analysers and gates.


This blog post was written by Simon Thompson. Soundman, musician, occasional DJ, and CEO/Proprietor of The Noizeworks. Live music equipment suppliers extraordinaire! Based around East London/Essex. UK. He hopes you find it useful and helps in your artistic and professional endeavours.....but......as with all his blog posts, this information is offered in an informal basis and he accepts no responsibility for any circumstances arising out of the use of this information or the inability to interpret it, etc. blah...blah.....blah. 






















Sunday, 23 October 2016

Technical: Practical Tips On Minimising Feedback and Maximising Gain. Part Two

Controlling feedback. Part Two. Physical counter-measures. Physically de-coupling loudspeakers and microphones.

In part one we took a look at what what feedback actually is and what causes it. With this information, we can now make better informed decisions with regard to speaker placement, stage monitor positioning, and equipment choice. 

The first thing that absolutely has to be said when talking about loudspeaker positioning is that safety must come before any other considerations. Particularly with small venues, there may be compromises to be made with regard to where your loudspeakers can be positioned for optimal sound and where they can realistically be located. The safety of everyone involved must always come before any other considerations. It may be rather obvious to say, but worth saying nevertheless. 

In order to understand the optimal positioning of loudspeakers relative to the microphones it is worth knowing a little bit about two things. Microphone 'pickup patterns' and loudspeaker 'dispersion'. 

Microphone Pick-up Patterns.

Most modern stage microphones have a 'cardioid' pickup pattern. This essentially means that they are more sensitive and pick up more sound at the front of the microphone. 'Pattern' is also sometimes referred to as 'polar-pattern'. Hypercardioid microphones narrow the pattern further. This pattern can vary depending upon frequency, but for our purposes all we really need to know is that the microphone picks up more sound from the front. 




Loudspeaker Dispersion Pattern.

Loudspeaker dispersion can be a little more complicated because they very often have more than one transducer. Usually a high frequency compression driver mounted on a 'horn' reproducing the mid/high mid frequencies, and a bass driver reproducing the low mid and lower frequencies, often mounted as a 'direct radiating' device. i.e. interfaces with the air directly in front of it without the use of a front mounted device such as a horn. This means that the dispersion can vary quite a lot with frequency. The horns used in modern loudspeakers can deliver quite a tight dispersion pattern, so the mid/high output of a speaker can be quite 'tight' or 'narrow', but the lower frequency signals reproduced by the woofer or bass driver may have a wider dispersion.  
The situation is further complicated slightly by addition of loudspeaker 'subwoofer' loudspeakers. The frequencies reproduced by this type of speaker tend to be so low that the output dispersion is very often 'omni-directional'. in other words it propagates sound equally in all directions. This means that subwoofers can sometimes present a unique challenge in terms of controlling feedback.


So now we know what causes feedback, it becomes obvious that we need to position the front-of-house speakers where they offer maximum audience coverage with minimal coverage of the stage area where the microphones are positioned. 

My diagrams below aren't the greatest, but you get the idea:





So, usually in venues and event spaces you will see the main front of house speakers in a PA system forward of the stage on either side. This is generally where you'll get maximum audience coverage and, since the loudspeakers disperse much less sound to the rear and side, minimal spill into the stage microphones. But there may be one or two other factors to consider with portable systems. 
Personally, I think height can be your friend. Getting mid/high loudspeakers nice and high on their tripods/poles, etc. Once again, with safety very much paramount. 
I would also advise, if possible, against stacking loudspeakers directly onto a stage. Although speakers may not disperse much sound to the rear and side, that may not be the case with reflections and resonances through the cavity or void beneath a wooden stage. Also, the subsequent resonances may transmit up through the stage, through the mic stands and into the barrel of the mic and the mic capsule, and whilst this may not be a feedback issue, the resulting unwanted 'rumble' may not be particularly desirable. 

Below are some diagrams of where you may position the front of house speakers relative to a stage, For me, this first option is not particularly desirable as it leads to problems with the aforementioned stage resonances, etc, and the speakers are quite close to the on-stage microphones  Sometimes, particularly in small venues you don't get much of a choice, but I wouldn't consider this arrangement exactly ideal.  


This second example is more desirable. It gets the mid/high cabinets up at ear or above ear level, and the sub bass speakers off the stage where they will create fewer stage reflections and resonances. If the stage is built into a wall, and the speakers are positioned against, or close to it, this can offer increased low frequency output.



The third option may be better again This places some distance between the stage and the front of house speakers. The additional benefit of this placement option is that if the speakers are positioned in the corner of the room, they can benefit from additional bass output from corner positioning. 



Reducing Feedback from Subwoofers:

As mentioned previously, subwoofers can be problematic with feedback because the natural dispersion of most subwoofers tends to be fairly omnidirectional. Some loudspeaker companies have developed larger subwoofers that can be arrayed to produce a cardioid or unidirectional dispersion, but these tend to be quite large units and the theory involves arraying several units. So it's quite a large scale project, and they have been developed primarily to assist large scale sound companies to reduce sound propagation from festival sites rather than a measure to help minimise feedback. 
Of course, physical barriers may be a help. In the above diagrams where the stage is built into a wall, placing the subwoofers either side some distance away will certainly help. 
Probably the best counter-measures for reducing feedback in subs lie within system design and electronics. Do the vocals need to be in the subs? Maybe just the bass drum, bass guitar, and keyboards need to go into the subs? In which case you'll only have the bass drum mic potentially feeding back through the subs (assuming you're DI 'ing the bass). A simple gate will take care of that. Much easier to control than a rake of vocal mics at the front of the stage. More of this in part three when we take a look at electronic counter-measures. 

Feedback and Stage Monitors:

Of course, one of the most challenging areas when trying to minimise feedback is stage monitoring. The speakers used on stage so that artists can hear themselves are always going to be positioned pretty close to microphones, and often on the stage floor. Artists and musicians very often want these speakers to be very loud (often unhealthily loud) so they can hear above both the ambient and amplified sound of the rest of the band. 

The most powerful means of getting the most gain before feedback from stage monitors tend to be electronic, but careful positioning of these speakers can certainly help.

Some hypercardioid microphone designs narrow the pickup at the side of the mic at the expense of rejection directly from the rear of the mic. Positioning monitors at the side and rear of these mics may be preferable to putting them directly at the rear. Not very good diagrams, but you get the idea. 


So the arrangement below may be preferable with many hypercardioid mic designs. 


Also, many speakers have rotatable horns for monitor use. This is now quite common among multi-purpose speakers that can also be used for front-of-house applications as well as stage 'wedge' monitoring. Generally speaking, a wide dispersion that spills sound vertically over the stage is not really required, so rotating the horn may help with feedback in the mid/high frequencies. Although interestingly, because the speaker is now on it's side, very often the horn will disperse wider vertically than horizontally, which may be preferable. All I can really say here is that experimenting with rotatable horns may be useful, but don't necessarily accept the manufacturers guide that one way is for front-of-house and one is for monitoring. 

Anyway. That's about what I've got on positioning loudspeakers for minimal feedback. Hope you find at least some of it useful. 
In part three we'll look at some of the electronic means of minimising feedback. Mainly graphic EQs, but also parametric EQs, and gates, etc. 

As with all my blog posts, this information is offered in an informal basis and I accept no responsibility for any circumstances arising out of the use of this information or the inability to interpret it, etc. blah...blah.....blah. 


  

Wednesday, 19 October 2016

Products: JTS CX-500 Miniature Condenser Microphones. Part Two: Product Variants. CX-500F and CX-500Du

JTS CX-500 Variants. CX-500F and CX500Du

In part one of our look at JTS' CX-500 Series of miniature condenser mics, we looked at the various models, their applications, and their associated power supplies and mounting options. We then took a detailed tour of the CX-500 general purpose version. 
In this second part, we'll take a look at a couple of the CX-500 variants; the CX500F clip on flute/piccolo mic and the CX500Du dual transducer mic system designed for lower frequency instruments such as cello and double bass. 



JTS CX-500F Flute Piccolo Microphone. 

As with the CX-500, JTS have very thoughtfully provided us with a rather informative video of the CX-500F in action. So maybe this is a good point to relax, sit back and enjoy some music:




So you can see from the video that the microphone is mounted onto the flute with a strap style clip that goes somewhere near the 'head-joint' of the flute. The microphone itself can then be easily positioned near the embrochure hole via flexible miniature 'gooseneck'. 
We have pondered whether the CX-500F would be suitable for a piccolo, and to be honest we're not a hundred per cent sure. We've not had anyone try it. Sound-wise, we think it would be fine, but we're not sure there would be room on the piccolo to mount the strap/clip. If anyone's tried it perhaps you could let us know.

Powering:

Like the CX-500, the CX500F can be powered in a number of ways. You can plug it into a compatible wireless transmitter, you can power it via phantom power from a mixer or mixer/amp just like any other condenser mic (for this, you'll need the JTS MA500 phantom power adaptor, or you can battery power from the PS510, or PS510M (these two units also work as phantom power adaptors, so you can either battery or phantom power the mic from these units.)

Sound:

Rather like the CX-500, the strength of the CX-500F lies in it's small dimensions, the ability to clip it to the instrument and the proximity of the mic to the embrochure hole. Because it's clipped to the instrument the mic moves with the performer, so you don't have to worry about the flute moving to and away from the microphone which you would with a traditional stand mounted mic. Because of the proximity of the mic to the flute, a healthy signal level is achieved with enough lower frequency response to produce a nice warm/rounded tone, and your mixer mic pre-amps don't have to be cranked to feedback inducing level. 
As with all microphones, it's worth experimenting with positioning to produce the desired result, but A CX500F mounted on the flute with the mic 1-2 inches from the source is a very good starting point. 

The Noizeworks CX-500F product listing can be found here. 


JTS CX-500Du Dual Transducer Microphone System:


JTS CX-500Du


The JTS CX-500Du dual transducer system is designed for instruments where better bass response is required. The CX-500 is an ideal option for violin, viola, acoustic guitars and mandolins, etc, but there is a limit to how good the low end response of such a small diaphragm microphone can be. This is where the CX-500Du comes in. 
By adding an additional boundary PZ transducer which also doubles as a mount for the miniature condenser, a more 'full range' sound can be achieved for cello, double bass, acoustic basses, etc.

Powering for JTS CX-500Du:

The CX-500Du is supplied as standard with the PS-510 dual power supply/phantom power adaptor/mixer. This has two inputs for the two microphone elements with a gain control for each. The two inputs are then mixed down to a single 3 pin XLR output. Power can be supplied by a single 9v battery, or via phantom power from a mixer or mixer/amp.

JTS PS-510 Power Supply/Phantom Adaptor/Mixer.

 Sound:

Again, close proximity miking here is a real boon. No cranked up mic-pres, no armfuls of EQ. The only real issue with the CX-500Du is setting the gain controls on the PS-510 for a balanced sound between the two elements. This system could, of course, be further enhanced by the addition of a second PS510. This would allow the two elements to be assigned to their own mixer channel, and so could be entirely controlled from the mixer and EQ'd and/or processed separately. 
The whole concept and idea is somuch more effective than pointing a stand mounted condenser microphone at the instrument. 


OK. So that concludes our look at the JTS CX-500 family of microphones. We hope you've found it informative and that it has answered any questions you may have had about the series. We'll continually update the posts with any new information as it arises. 

At The Noizeworks, we keep stock and demo versions of all the CX-500 series products, so if you think one of them may be what you're looking for and you're in the South East of England/London area then give us a call or email us and you can stop by and check them out. Bring your instrument and we'll plug it into one of our demo rigs. 
but do contact us first before travelling to make sure we've got the item and we're around to look after you. 





Disclaimer, Please note, etc, blah, blah......: As with all my blogs, the information contained here is presented in an informal manner to assist musicians and sound professionals in their artistic endeavors and equipment choices, etc. I accept no responsibility for any subsequent situations that may arise out of this information, errors that may be contained within, or the inability to interpret it correctly.
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Friday, 14 October 2016

Products: JTS CX500 Series Miniature Condenser Microphones. Applications, Information and Accessories. Part One.

The JTS CX500 miniature microphone has become one of our favourite and indeed best selling products, but it's modest selling price sometimes belies it's quality and versatility. There are also now a number of different versions available for different instruments which supplied with different mounting accessories and connector options. So we thought it would be a great idea to put together a short blog post explaining the different models, their applications and a look at some of the different mounting options available. 
We'll split this information into two parts. 
In part one, we'll introduce the CX-500 family of microphones and take a close look at the general purpose CX-500
In part two, we'll take a look at the specialised variants. The CX500F flute mic, and the CX500Du dual diaphragm mic system which offers and additional PZM element for enhanced bass reproduction. 
We stock all CX-500 Series products and have demo versions. The Noizeworks is based in Rainham, Essex. UK. So if you want to try out any of the mic products with your instrument, then give us a call/email. All the contact details are on our website. 
www.thenoizeworks.co.uk

So anyway. Let's start our detailled look at these great little microphones.......


Introduction:

The CX500 Series of condenser microphones have been developed by JTS to offer a versatile miniature condenser microphone for use with a range of acoustic instruments at a much more affordable price than some of the more 'esoteric' products currently on the market. To offer versatility, a range of different models, mounting options, pre-amps and interfaces have been developed. Here we will explore and clarify these various options and offer advice on the application of the various microphones and options.

Microphone Models and Accessories:


Microphones:

CX-500: General purpose miniature condenser microphone for use mainly with acoustic and orchestral stringed instruments such as violins, violas, acoustic guitars, mandolins, banlos, etc. 
CX-500F: Miniature condenser microphone with mounting and flexible miniature 'gooseneck' particularly designed for use with flutes. 
CX-500Du: Dual transducer system specifically designed for enhanced bass reproduction. Designed for lower register stringed instruments such as cello and double bass but can also be used for violins, violas and acoustic guitars. 

Pre-Amps and Power Supplies:

MA500: Phantom power adaptor. Allows CX500 and CX500F to be used as a standard condenser microphone with mixers and mixer amps supplying phantom power down the microphone cable.  
PS-510: Battery/Phantom power supply. Facilitates powering of CX-500, CX-500F and CX-500Du via batteries or phantom power supplied by a mixing console. 
PS-510M: Enhanced version of PS-510 with headphone output for local monitoring.

CX-500 Miniature Condenser Microphone System:

We'll start by taking a look at the general purpose CX-500 and begin by taking a little break at this point, sit back, watch a video, and listen to some nice relaxing music:




JTS have provided a very useful video showing the application of the CX-500 mounted on a violin, so you can see how the microphone bridge mount works and get a flavour of how effective it can be sound wise. Obviously, this is only a video and a lot will depend on your computer speakers, etc, but you can get an idea of how much more effective close miking of instruments can be. 
It would be impossible to get any kind of stand mounted microphone anywhere near as close as this miniature mic, and a stand mounted mic would also restrict the movement of the player. 
By mounting the mic on the bridge of the instrument we can get very close to the instrument and get maximum lower register response through close proximity. 'Proximity effect' is the better bass response achieved through positioning a microphone closer to the source. 
The video also shows how effective a microphone can be in situations where the permanent mounting of pickup systems in instruments is unwanted or not possible, such as valuable orchestral instruments. 


So let's take a closer look at the CX-500, it's mounting options and pre-amps/interfaces. 
At the time of writing, the CX-500 was being supplied only with a number of mounting options and not packaged with the MA-500 phantom power adaptor, so the MA500 will now always need to be purchased separately. A CX-500 without the MA-500 adaptor can only be used with a compatible wireless system beltpack, or the PS-510/M battery/phantom power supply. 

Below is an image of the basic CX500 kit and accessories:



The CX500 microphone itself is at the top. It has approx' 2.5M of cable and terminates in a mini 4 pin XLR. There is a pack of replacement windshield. Two bridge mounts are shown bottom right, 5 stick-on mounts are shown and to the left are replacement stick on covers for the stick on mounts. In the centre is the MA-500 phantom adaptor not now supplied as standard with the CX-500

Powering Options:

The powering of miniature condenser microphones like the CX-500 can be a source of confusion. So we'll attempt to clarify this here:
Because it's a condenser microphone, the CX-500 has to be powered. This can be achieved in a number of ways: 
1) It can be plugged into a wireless microphone belt pack system. JTS wireless microphone beltpack systems terminate in 4 pin mini XLRs so you can plug the CX-500 into a range of JTS wireless systems for complete freedom. No additional power supply is required.
JTS Beltpack Transmitter.
2) Via the MA500 phantom power supply. Most modern mixers and mixer amps are capable of providing phantom power down the microphone cable. For this application you need the MA500 phantom power adaptor. This really allows the CX-500 to be plugged in and powered rather like any other condenser microphone. One side of the MA500 is a 4 pin mini socket for the CX-500 and the other side is a standard 3 pin XLR plug. Plug the CX-500 into the 4 pin mini XLR socket and connect a standard XLR-XLR cable from the MA500 to the mixer. Turn on the phantom power, bring up the channel and off you go. Incidentally, the MA 500 also has a handy clip that allows it to be clipped onto a belt or clothing strap, etc so it's not just dangling around your person or sitting on the floor.
JTS MA500 Phantom Power Adaptor.

3) Via the PS510/M phantom/battery power supplies. These units provide power to the CX-500 where there may be no phantom power available. Such as busker amps, etc. The PS510/M also offers the additional versatility of allowing powering via phantom power. So you have flexibility depending upon the available mixer/amp/PA setup you may be using and don't need to purchase an MA-500 for situations where phantom power is available. 


JTS PS510 Battery/Phantom Supply/Adaptor.


Mounting Options:

The CX-500 is supplied with a number of mounting devices. 
1) 5 x 'stick-on' mounts. These versatile little mounts are great for a variety of instruments. Violins, violas, mandolins, acoustic guitars, banjos, saxes, trumpets, trombones, and a variety of percussion instruments. Just stick the mount onto the instrument in the desired position and clamp the CX-500 into the mount using the cable. Her are some examples on acoustic guitar and a piano sound board:




Now I think at this point it's probably worth exercising some caution and common sense. According to JTS, the adhesive used on the stick on mounts have been specially developed and formulated to not cause any marks or damage to instrument finishes or lacquer. But I would hesitate to use these on very valuable instruments.

2) 500HG and 500HG1 bridge mounts are supplied. One of each. These are the devices the lady in the video was using. They are for over and under string bridge mounting of the CX-500. You can experiment with these and find out which works best on your particular instrument. These fit onto the strings behind the violin/viola bridge and then the mic cable clips into mount. As below:



Obviously, these mounting devices can be fitted or removed and make no contact with the body, so can be used with perhaps more valuable instruments. 

Of course, the CX500 mic is so small and so discreet that you can really mount them anywhere you like with a piece of tape. Put a piece of tape across the cable, just behind the mic capsule and stick it wherever you want! Use your imagination!


Advantages, Sound Quality, and Positioning:

The power of the CX-500 microphone lies in it's size. It's tiny dimensions alongside it's supplied mounting options, means that the mic can be positioned almost anywhere on the chosen instrument. It's true that smaller diaphragm microphones won't reproduce bass quite as well as a larger diaphragm mics, but as mentioned earlier, what you lose in capsule size, you gain much more by proximity. Because you can get the mic so close to the instrument source the low end response becomes more than enough and, the mid/high reproduction is detailed, bright and vivid.
Again, due to it's small size, and close proximity positioning, you don't need to crank the gain of your mic pre-amps. This means that background noise can be minimised and also high gain before feedback can be achieved. Anyone who has ever attempted to mic orchestral instruments from a distance with stand mounted condenser mics will testify how difficult it can be sometime to get enough sound into the system before it reaches the verge of feedback. 
Because you'll get more sound from the closely positioned mic, you can employ effects and processing more effectively. Adding reverb or deploying compression becomes so much more...well.....effective!
The use of all microphones will benefit from experimentation in terms of positioning, proximity and the use of external processing and EQ. The great thing about the CX-500 is that, because of it's small size, experimentation with positioning can be carried out. You can place it almost anywhere. 
I've experimented with and tried out the CX-500 on a range of instruments including violins, guitars and percussion instruments and have achieved great results in a short space of time with pretty minimal use of EQ and outboard processing. It's most effective roll is with orchestral stringed instruments such as violins violas and cellos. Fit the CX500 somehere on the body of a violin pointing towards the area where the bow meets the strings, or mount it via one of the bridge mounts, add a few dbs of bass EQ around 80-120hz and you'll be pretty close to a great sounding miked up violin. 
It works great with mandolins and guitars, but very often there are alternative options for these instruments such as pickups, and there are many great electro-acoustic guitars on the market with pickup systems, pre-amps and EQ ready fitted. But if you have an instrument without a pickup, or have an instrument on which you don't want to fit one the CX500 works great. 
Same really applies to saxes and brass instruments. It works really well, but there are other mics with larger diaphragms and better mounting options available such as JTS's own CX508 for these instruments.
They can work really well on some percussion instruments. Stick a couple of CX500's onto a pair of bongos and you'll get a great sound without the clutter and sight line problems of stand mounted mics. 
And, of course, for sound boys and girls and hire companies, keeping one or two of these versatile little mics in your kit bag will leave you better equipped for covering the many different situations and surprises you might be faced with. 

Conclusion:

So that about covers the CX-500 and hopefully explained and clarified some of the mounting and powering options available for the microphone. Remember, if there's anything your unsure about, give me a call or send me an email. All the details can be found at www.thenoizeworks.co.uk
Because, I use these mics in my own, admittedly now quite occasional sound engineering jobs I know them pretty well and I have demo models that you are welcome to stop by and try if you're based in or around the South East of England/London area. 

In part two, we'll take a closer look at the specialised CX-500 Series mics, the CX500F flute mic, and the CX-500Du dual diaphragm mic system for lower register instruments such as cello and double bass. 




As with all my blogs, the information contained here is presented in an informal manner to assist musicians and sound professionals in their artistic endeavors and equipment choices, etc. I accept no responsibility for any subsequent situations that may arise out of this information, errors that may be contained within, or the inability to interpret it correctly.







Loads more technical stuff, opinion, product news and specials coming during the next month, so why not subscribe, or follow us on Facebook and/or Twitter 


All the best, Simon. The Noizeworks







Wednesday, 12 October 2016

News: Noizeworks Monthly News. October 2016

JTS microphone products return to The Noizeworks. We were pretty much in 'on the ground floor' with JTS several years ago when they first arrived in the UK and they've been one of our favourite (and best selling) lines ever since. Offering high performance with value for money, their range of miniature, clip on and drum mics offer great sound for musicians and sound people alike. Highlights from the range include the amazing CX500 family of miniature condenser microphones which are great for all types of flute and string players/ensembles, the CX508 clip on brass/woodwind condenser, the TX2 kick drum mic, and the NX Series vocal/instrument mics. We are currently developing the products and the information on the website. The initial raft of products can be found here>>>>>>

We've been going through our technical blog posts and are in the process of converting them all to easily downloadable/printable pdf format. The first couple on gain structure and the correct setting of power amp controls, and an explanation of pre and post fade auxes are now available at The Noizeworks website. More are following, including our explanation of stageboxes/multicores and D.I. boxes, and our latest posts on acoustic feedback and how to combat it. You can find them by clicking the image on the right or here>>>>>>>>
A raft of special offers are available this month including the powerful yet lightweight Samson MXS2800 power amp. Thanks to swith mode power supply technology, this little beast delivers 2 x 850 watts (RMS 4 ohms) yet it's only 1U of rackspace high,  weighs just over 5kgs and is only 36cm deep. Add to this a bridge mode which turns it into a 1 x 3400 watt mono amp. So you could combine two of them which would give you the option of a 4 x 850 watt channels or 2 x 3400 watts and still weight less than 11kgs!. Offer price is £369 against an rrp of £492. More info>>>>>> . Also from the Samson power amplifier stable comes the SXD Series amps. This range of three power amplifiers offer on board DSP processing including filter/crossover, EQ, variable limiting and delay. Ideal for monitor and front-of-house applications. Particularly for use with analogue desks where there is no on board DSP processing features. Great deals are now available on these amps with prices way south of the rrps. Go to our Samson amps page for more details. 


Various deals this month on the rather excellent AKG D5 dynamic vocal/instrument mic. You can now get one packaged with a boom mic stand and a 4.5M XLR-XLR cable for a mere £79 English pounds (rrp: £132) more info here>>>>>>>. For clients looking to by a number of mics, then we can offer the D5 Sixpack (i.e. 6 x AKG D5's) now for £345 (rrp: £582). Details of this deal can be found here>>>>>> Ideal for clients who may be looking for a quantity of high quality mics without breaking the bank e.g. rehearsal rooms, schools, event spaces, churches, etc. 




Our special offers list has now been updated for October and you can view/download/print it here>>>>> This also includes lots of other information about The Noizeworks including all of our website, social media feeds, blogs, etc. So why not take a look. 



Finally, a reminder that the Yamaha TF Series consoles are now on demo. Anyone wanting to sit down and spend some time with one is more than welcome to stop by. We are based in Rainham, Essex. Just East of London by the M25. Just give us a call or drop us an email letting us know when you'd like to come in. Bring music/headphones, we'll supply coffee and biccies! Our dedicated website portal covering all the latest updates, videos and information on TF Series is available here>>>>>>


Disclaimer, etc: As ever with special offers, etc, all the items are subject to availability and the prices are correct only at the time of writing/publishing, etc. 

Thanks for reading!