Core Sound Microphones
An Amateur Recordistís View
Les Turoczi
1 May 2001

Specifications

Products under review:
Core Sound Low Cost Binaural microphones ($75)
Core Sound Low Cost Stealth Cardioid microphones ($75)
Core Sound Binaural microphone set ($260)
Core Sound Stealth Cardioid microphone set ($250)
Core Sound High End Binaural microphone set :using DPA 4060
Capsules ($950)

Core Sound
574 Wyndham Road
Teaneck, NJ 07666
201-801-0812
Web: http://www.core-sound.com
Email: moskowit@core-sound.com

Lovers of reproduced music are well aware of the equipment chain needed for listening to their tapes, LPs, CDs, radio, etc. While it is possible to become engrossed in many of the important details of each step of the chain, it is just as important to think about where and how the whole process starts. Clearly, musicians are at the front of the equation, but shortly after them, in the recording studio or concert hall, come the microphones. This review will focus on relatively new approaches to microphone styles, designs and usage and hopefully along the way, some new insights and ideas about sound recording and reproduction may emerge, especially for amateur tapers.

I have always been curious about live recording and even made some feeble attempts at it about 25 years ago when I was willing to drag my Tandberg reel-to-reel tape recorder and Sennheiser mics to live concerts in my locale. While it was fun and educational, most of those tapes were inferior enough as to discourage me from pushing along at it. Then about three years ago the opportunity arose to purchase a portable DAT machine of good quality and a pair of more-than-adequate cardioid mics. The musical community in my area seemed willing to let me set up the gear and fool around. With a bit of effort, a steep learning curve, and many false starts, I eventually started getting good results. That system evolved further equipmentwise and now the results are even better. This has led to recordings that not only capture the music well, but also help in my understanding of sound and sound reproduction.

Last summer while visiting a good friend/jazz musician in New England, I had a chance to see and hear his pocketable minidisc recording system, which included some tiny homemade microphones. While not of the highest fi, the sound was credible, and I became interested. This led to a fair amount of research into small, portable minidisc machines and appropriate microphones. What I mean by appropriate is really the gist of this article. There are some very small, really tiny, quite serviceable mics on the market today, and I wanted to see what they could do to effectively capture music. Just reflect for a moment on the mics in your cell phone, camcorder, or other related toys/appliances, which we use regularly. All of these technological developments have stimulated rapid growth in mic evolution and we have become the beneficiaries of that work.

In my research into the history of this field, it seems that the folks at Panasonic (Matsushita) were among the early manufacturers who saw a need to make small, higher fi mics. They introduced items such as the WM61 capsule which is roughly the size of the eraser on your old-time wood-clenched #2 pencil. Interestingly, several do-it-yourselfers climbed onto the bandwagon and began all sorts of experiments which utilized capsules of this ilk. My buddy in Maine got his pair of slightly modified mics from a friend, also a musician, who started tinkering with that WM61 capsule and found the results more than serving his basic recording needs. What was particularly fascinating about all of this was the miniscule size of the units and the fact that this chap found a way to make the mics fit onto a pliable stretch of wire that could be draped around the back of your head and over the ears. Depending on your head, hair density and color these things just about disappeared visually and that made them a contender for the "stealth" taper crowd. With many DIYers taking similar approaches, more mics of these sorts made their way into the hands of amateur recordists around the country.

You can find various internet sites devoted to stealth recording, but my interest really wasnít for the questionable "stealthiness" of things. Rather, I just became intrigued about the possibilities that were open to me as an amateur taper who didnít want to clutter up a concert venue with mic stands, big mics, DAT gear, etc. Since then I have found even better small mics thanks to the fine efforts of Len Moskowitz at Core Sound and I want to let you know about his gear here. Incidentally, I always ask for permission to record from the performers at the concerts I attend and anticipate taping. This is easy for me since almost every event Iím interested in is at a small venue and is usually a concert devoted to classical or folk music where the artists donít seem to mind me, especially, since all of what I do in this way is so unobtrusive. If you think this has appeal for you, I recommend that you also seek permission before taping. We are not promoting illegal behavior here.

Core Sounds (with an excellent and informative website, plus helpful links, at www.core-sound.com has taken all of this to much higher levels. Len screens capsules from selected manufacturers and then proceeds to do meaningful modifications to them to improve frequency response, noise, signal handling, etc. He fashions a variety of matching supplemental equipment such as power supplies, cables, connectors, and other useful components. He also sells ancillary electronics from other manufacturers which help to make the entire recording process even more successful. I shall evaluate the mics he has customized and, at the end, report on special products from a renowned mic maker, which he also distributes.

The approach I used in evaluating Core Sound products involved, for the most part, recording to minidisc using a Sharp 831 MD recorder/player. This tiny unit is quite good, although not state-of-the-art, and it offers ease, convenience and unobtrusiveness during actual concerts as noted earlier. The mics were typically attached to my eyeglass frames during the performances, although they can be clipped to shirt collars, jacket lapels, and other points on clothing that may be convenient. Experimentation is important to be sure that the mic pickup pattern is satisfied and that other noises are minimized (such as your own breathing). To get a sense of critical differences between the various models of mics under review I carried out a few controlled experiments with the help of a friendly pianist who was willing to play the same piece of music many times while I substituted one mic type for another. That information, along with actual concert recordings, ultimately led to some positive conclusions about Core Sound products and this enterprise at large.

Microphones have pickup patterns designed into them for maximizing signal retrieval under different conditions. Omnidirectional mics usually gather a very broad area, including details from the sides and partially behind the mic. Cardioid mics come in a variety of narrower pickup patterns and can range from moderate to highly pinpoint patterns depending on capsule construction, etc. Youíll notice that Core Sound denotes part of their offerings as Binaural units. For those mics the intent is to have the actual mic capsules essentially sticking straight out of your ear canals, if that were possible. With the clips provided by Len you can get pretty close to that arrangement and the spatial sense this conveys on listening through headphones is very enveloping. For my evaluations I asked Len to let me try a mix of styles and that was helpful in developing good insights into his units. (Some mics, which needed external battery power packs, were used as specified.) To make life easier, Core Sound sells mics from entry through moderate to professional levels with commensurate pricing, as listed in the headnote. Again, I had the chance to sample most of those ranges.

Letís begin with the entry level products, the Low Cost Binaural and Low Cost Stealth Cardioid mics. I started with the Binaural mics (LCB) first, since I had discovered in my ongoing regular taping activities with the DAT and conventional mics that I typically enjoy the sense of the venue which omni-type mics yield. The sound was clear and tonally balanced but, considering my position in this choral concert venue, somewhat distant in perspective. The sound was reminiscent of what I had experienced with the homemade units from my buddies in New England. Interestingly, those DIY units had a bass emphasis (perhaps heaviness) which did not occur with the LCBs. This may reflect the basic selection process Len uses to cull out questionable capsules. When intermission came along, I switched to the cardioid units (LCSC) and found that these did indeed give a closer spatial perspective, but the loss of room ambience did not particularly suit my taste. Certainly, they performed as advertised, but for an acoustic concert of this sort, where hall effects are desirable, I preferred the LCB mics clipped to my eyeglasses just in front of each ear. I did try them in other performances and found consistent results. In concert settings where amplification of the performers is common, the LCSC mics make for a more suitable match, especially if your placement is somewhat back from the stage, etc. The cardioids do have the ability to ignore random noises, including audience members at your side or behind you. Both the LCB and LCSC mics were operated directly from the Sharp 831 MD, which provides basic "phantom" power through the mini-plug connector; therefore external battery supplies were unnecessary here.

The natural progression of things led to the Core Sound Binaural mic (CSB) set, along with the Stealth mic (CSSC) set. Each requires a battery box for powering and there are a few optional variations on those boxes based upon filtering needs. The sonic performance of these relatively expensive models was more than a step above the economy versions. In all trials, which included pipe organ recitals, large and small choral groups, folk singers and a small jazz quartet, the sound took on polished characteristics, including heightened tonal purity, better separation of instrumental parts, and a greater freedom from compression, i.e., a better sense of headroom. When running the playback through my "big rig" sound system it appeared that the cardioid mics added a small degree of brightness to the sound, but it never became irritating or offensive Ė just a bit mid-strong. Yes, I did again prefer the binaural units because of the space retrieval abilities, but both sets delivered performance enhancements which I believe justify the additional cost, relative to the LC versions. In the name of practicality, and with my particular musical preferences, the CSB mic set satisfied most of my demands and pocketbook. Club performances, stadium venues, etc., probably are better served with the CSSC set, and you can have the luxury of finding out which is best for you since there is a reasonable trial policy from Core Sound.

To put it over the proverbial top, I sampled the High End Binaural mic set from Lenís fine stable of offerings. These 4060 capsules are made by Danish Pro Audio (DPA), whose name you may be familiar with because they were previously called B&K, i.e., Bruel and Kjaer, a well known, highly regarded, pro-world mic maker. John Atkinson uses some of their mics on his Stereophile recordings, as does almost everyone else in quality recording. My experience with these babies was absolutely thrilling. I did not think that mics this tiny Ė they are smaller than pencil erasers Ė could do what they did. The spatial rendering was wide, deep, high and proportional to the real thing, and tonal balance spot-on, including a deep, full, clear and thunderous bass, especially on pipe organ pedal notes. Midrange detail was accurate, but not overly etched. Soprano voices came through with lifelike, natural sibilance, as opposed to exaggerated edges that can often happen. The top end extension seemed to be unlimited, adding "air" that did much to make the recordings sound convincing. Let me pause to note that while some of this enhanced performance came through on minidisc, the real deal was only obvious when I ran the HEBs into my DAT machine, which was possible since Len provided mini-plug to XLR adapters. The benefits derived here were not fully realized on any of the minidisc sessions, BUT should you have a DAT machine, the HEBs will make you take notice.

There is one additional approach I had the opportunity to try on two occasions in concerts where I was seated in the front row of a balcony. Instead of clipping the mics to my eyeglasses, here I had the chance to tape the mics to the upper surface of the balcony wall and separate the capsules about two feet apart. This had a very nice impact on overall stereo dimensionality. It does mean that more of the room acoustic becomes obvious in a distant balcony position, but the cardioids (CSSC) worked nicely at keeping the chorus in a focused perspective. There was less interference from audience noises since there were no bodies directly in front of the mics. Having this mic separation under those specific circumstances was not hard to do but would prove rather more difficult in a non-balcony position. This prompts me to observe that finding an ideal seat position in any live concert is always a concern when doing this type of recording. I found that sitting closer to the performers offers a sonic advantage, especially when having to contend with coughers, talkers, paper rattlers, etc. On the other hand, learning to live with some of these distractions does allow you tell your listening pals that they are hearing something "live" Ė how it came across during the actual event.

In conclusion, if you are thinking about trying some of these amateur recording approaches, the minidisc recording technology will serve nicely to capture live music in a reasonable fashion through any of the Core Sound mics or mic sets. I do think the middle level products like the CSSC or CSB mics offer excellent performance for the cost. Any beginner would be well served by the entry level LCB or LCSC products, particularly if the listening equipment is less than the highest fi. For those who want to go the DAT route, the sound quality improves to a significant degree and the better mics offer lots of fun and enjoyment. In the final analysis, having the joy of live recording in this convenient and easy way offers rewards. There is little equipment to cart around, less distraction for you while actually enjoying the concert, and it is not a terribly expensive way to get into this side of music reproduction. No, it doesnít substitute for carefully setting up my Earthworks QTC1 omni mics on stands, fiddling with the Tascam DA-P1 DAT machine and keeping mic cords and battery packs under control. Such as this affords a better recording, but at significant financial investment. Furthermore, the opportunity to do it this way is not always available. I look forward to using both approaches as time, space and opportunity present themselves. An additional bonus: my listening acumen has benefited from being able to hear performances at home that occurred only minutes or hours earlier. Knowing how it came across live and then how it appears on the home system can be very educational for us hardcore audiophiles!

I heartily recommend a visit to Core Soundís website where details beyond this report are available, along with insights and information that audiophiles care about. If you have an interest and donít know where to begin, call or email Len, who is, by the way, an electrical engineer. He is very informative and can give guidance and direction about the overall topic of equipment options and recording techniques. This project has been a treat to undertake. I hope that I have stimulated some of you enough to begin your own explorations of live recording. Cheers!