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Question about mixers for a microphone

 

New member
Username: Healinghands33

Post Number: 1
Registered: Oct-11
Hi,

I'm new to this site, so I may well be in the wrong part of the forum, for which I apologize, but I normally don't deal with sound systems at all, so if someone here is smarter than I am (and that won't be hard!) and can either send me to the right part of the forum or, better yet, just answer my questions, I'd really appreciate it.

Let me also state right up front that I'm not sure exactly what I need, as I really am not familiar at all with sound systems, but I'll try to state my situation as clearly as I can and hope that someone can help.

Here's my problem. I teach 2-day seminars in various countries and, for large groups, find that I need a lapel mic to help save my voice. I can rent a lapel mic setup at each location, which is very convenient and requires no effort or thinking on my part, but they often charge fortune for a two-day rental of any audio equipment.

As a result, I want to see how much equipment I can provide and carry with me to help keep the cost down, though any equipment has to be small and light, as I need to carry it on a plane. I have my own Azden lapel mic and belt pack that I use for my camcorder, which sends a signal to its matching Azden wireless receiver, which then terminates in a 3.5 mm. mono plug. Most of the places I teach in are either universities or hotels, so they have sound systems with speakers built in, but almost always have to source a lapel mic setup from an audio rental company, and that's where the huge cost comes in. In very simplistic and uninformed language, what I THINK I need [Please correct me if I'm wrong] is a very minimal, lightweight mixer that will take the 3.5 mm. male mono input from my Azden wireless receiver and do whatever magic it does so that when I plug the output of the mixer into the resident sound system, my voice will come out of the speakers.

Here are my questions:
A) Do I in fact need a mixer, and if so, is that all I need?

B) If I need a mixer, is there a certain best brand to consider for a lightweight, small, and inexpensive unit that will be easy on both my baggage allowance and my wallet? I've read up on Behringer and Azden, but would love to know better choices if they exist. Brand names and model numbers would be both welcome and appreciated.

C) Am I correct in thinking the mixer needs to be plugged into an AC electrical source? If so, I am currently teaching primarily in Australia and New Zealand, where the normal electrical supply is 240V, 50Hz; will that be a problem, or do mixers accept a wide range of voltages and Hz, much as computers do?

Since I really have no idea exactly what I need here, any and all help will be greatly appreciated.

Thanks for any help you can provide, and for your patience!
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 16881
Registered: May-04
.

Do you use your camcorder to record your presentations? If so, then you can consider using your present mic/receiver as the main mic/receiver system and making it more compatible to other systems. In this case you might check with the manufacturer of the mic/receiver (Azden) to see whether they produce a receiver with more than one output line or with multiple line outs of more than one configuration; say, 3.5mm. RCA, XLR, etc. This would make your system more flexible when it needs to adapt to an existing system. This, however, would only be my choice should you want to get out of this for as little cash as possible.



A problem faced when answering your question would be; what is the "line input" configuration of the university/hotel systems you are adapting into? The only answer to that question is, there is no answer due to the wide variety of systems you might encounter. This, then, is your real issue and what you must address first and foremost.


I'm going to assume most of these hotel/university systems are simply not set up to accept a 3.5mm plug and, rather than make adaptations to their system, the soundtechs prefer to put the burden on you to make their system work. Which is, by most accounts, the accepted way for soundtechs to go about the ever-changing requirements of touring productions. Unless you ("you" referring to all travelling shows from one man puppet shows up to Cirque Soleil [of course, you might consider introducing the element of mime into your presentation which would eliminate a substantial portion of your problems - though you will face being ostracized by immense groups of people and might be forced to work your way out of an imaginary box at some time]) travel with your own self contained system, compatibility will always be an issue. One up front problem would be whether these world-wide systems can accept an "unbalanced" line input, If so, then adpating your 3.5 mm plug to, say, an unbalanced 1/4" plug or to a single ended RCA should be do-able and not that difficult for any competent soundtech willing to expend a small amount of effort. They pretty much should have those connectors in their bag of goodies, if they would only look. How open they are to adapting each incoming system to their equipment is then the issue and most soundtechs are not too accommodating in that respect. And for good reason as we will see in future episodes - stay tuned to this same channel next week!




Your mic receiver should be outputting a "line level" signal - a signal with a sufficient Voltage component to drive any amplifier to a reasonable level. You'll have to verify this yourself since you've provided no model number or real information for the mic/receiver system you own. In the system specs (found in the back of the owner's manual - which you should still have and have already memorized, right?) there should be a specification number which states the "output voltage" of the receiver. If that number is larger than 1.0 Volt, then your receiver is sending a "line level" signal and it should be adaptable to any amplifier world wide as the rest of the world still operates on the same Voltage once it is turned into an audio signal. If the number is lower than 1.0 Volt, you will require an intermediary "pre amp/mixer" to step up the Voltage before it can be input to an "amplifier".

A few issues here though; first, your mic is undoudtedly sending an "unbalanced" signal. Not all amplifiers will like an unbalanced input and some have nothing other than "balanced" inputs making them far more "incompatible" with your system - or, at the very least, more of a headache for the soundtech who doesn't like to have headaches. For any amplifier which would accept an unbalanced input, either a RCA or a 1/4" plug would be the appropriate input plug-to-jack configuration - though 1/4" plugs/jacks can come in different wiring configurations and this still might not solve your problem since it will not make the soundtech's headache go away. Therefore, if your mic receiver outputs a "line level" signal - 1.0 Volts or higher - and you wish to carry around a few connectors and obtain sufficient knowledge of working sound systems to discuss adapting your mic system to their "amplifier", carrying a decent collection of plug adapters would be all you require. Till, that is, you run into the stubborn soundtech who has set a rule that the guest does not get to decide which system works with their system. That shouldn't take long given the attitude of most soundtechs who are trying to protect their gear from the poorly equipped and uninformed-about-electronics wandering minstrals of the motivational speaker circuit. And, besides, any microphone wired through half a dozen adapters which serve only to keep the minstral from buying "real equipment" isn't a confidence builder in the first place. Can you say "hummmmmmmmmm"?

Second, if the university/hotel "amplifier" does not accept an unbalanced input - most should, a few will not, then you would have to be concerned about plug wiring. "Balanced" lines are typically sent between components through low capacitance cables which are terminated in "XLR" plugs. XLR plugs have more than one pin (and can have anywhere from three to five pins, further complicating the issue) - which is required for the "balanced" line - and all those pins can be configured in multiple ways. Should you plug an XLR which is wired "pin 2: hot" into any amplifier, pre amp or "mixer" which is wired with, say, "pin 1: hot", well, the result could be anywhere for simply no output signal to a damaged amplifier. The former would be a set back for you while the latter would be a costly disaster for the soundtech.

Can you see why most soundtechs are fairly protective of their equipment?

Adapting the incoming system of the minstral show to their equipment is most often a risk they prefer not to take and even more so when the incoming system isn't at all understood by the incoming minstral. It's inevitably simpler - and far, far safer - for the tech to have the incoming system be rented to their approval. They should provide model numbers and a contact for the rental and everyone is happy other than the minstral who must pay the rental fee.



Now, do you need a mixer?

Probaly not.



With only one microphone what would you "mix"? A "mixer" means you have more than one source - two lapel mics, or a lapel mic for you and a drum mic for the head-banger who accompanies you to provide timely punctuation, or a lapel mic for you and two drum mics for the head-banger and his "friend" plus a mic for the goat you travel with (well, you can see this can become very ridiculous in quite a short time) - which you wish to "mix" down into one single output signal. Since you appear to have only the one lapel mic, you have no real need for a "mixer". However, should your wireless receiver not be outputting that line level signal strength - 1.0 Volt or higher, remember? - you would need a "pre amp" to place in the signal path between your wireless receiver and "their" amplifier.



Actually, most of what I said to this point is a lie - or a minor evasion to be more accurate. Most university/hotel sound systems will have you plugging your equipment into their "mixer" - not their "amplifier" which is yet another piece of equipment to give the soundtech headaches - which then feeds the signal to their "amplifier". And here's the point you really must contend with, traveling sound systems are not generally capable of being all things to all other things. "Things" being your gear and "other things" being the hotel/university systems. While there is general equanimity between components, there has also arisen through the years the desire from equipment manufacturers to have greater control over which components you can buy to pair with their own. In other words, should you buy, say, a "Electro-Vocular" amplifier, well. Electro-Vocular would prefer you also buy more equipment from them and not from someone else. To tip you in that direction Electro-Vocular (through those b@stards in their marketting department and the follow like sheep engineers they employ) will build in just enough "personality" - a pin configuration or connector type, an input/output impedance/sensitivity, etc - to limit your choices. Should you - the travelling minstral - run into a hotel/university which has been equipped with Electo-Vocular gear by a soundtech who views Electro-Vocular as the be all and end all of sound reinforcement, the chances of your travelling system being adapatable to their state of the art Electo-Vocular system will be about the same as Rick Santorum being elected the next US President by a landslide margin.


(Excuse me while I take a moment to ROTFLMAO!)


Hopefully, by now you have some idea where all this is heading. In short, there is no one system which will be compatible with every sound system and every sound system technician you will encounter across the globe. Therefore, in my estimation and from my experience as a sound technician who fiercely gaurded my equipment from foreign interlopers, I would say you have three basic choices.

1) You can continue to rent compatible systems in each location. It should be a tax write off anyway - unless we get a Herman Cain "999" plan (excuse me while I take a moment to shudder) - so, while rental equipment eats into your profits somewhat, you get the tax credit at the end of the year to help pay for your extravagant lifestyle as a globe-hopping minstral.

2) You can contact a few manufacturers of wireless mic systems and try to come up with a workable system which would have the broadest compatiblity with the numerous systems you will encounter.

3) You can purchase a self contained sound reinforcement system which you carry from location to location and this does away with any equipment compatibility issues in each location. The soundtech has no headache and you have a consistent sound from location to loaction - plus a one time tax write off.



"1" offers no change so this should be fairly simple to make work.

"2" would be reasonably simple to accomplish though it will require you doing some research and some calling - as will "3". Whatever you buy will never be 100% compatible with each and every system you encounter so you will have to make some concessions to either make the system as compact and workable as possible or you will probably have to decide which system is simply the most compatible overall and live with the trade offs.

When it comes to adaptability to each country's local Voltage requirements, you'll narrow your choices right there. You can buy a battery powered system and have your presentation rest on the life of a battery - not always the best choice but often a workable option. Or you can buy a system with the option of changing the incoming Voltage. This can be accomplished through either a simple transformer type device which allows any electronics equipment to operate on any Voltage - no different than the device which adapts your razor or radio to each country's elctrical system only larger and more expensive due to the current/amperage demands of sound reinforcement gear. This should provide a reasonably broad selection of equipment vs finding a system with built in adaptability to each electrical system. Requiring a switch on the rear of the component to adapt the gear to another location/Voltage would further limit your choices when shopping. For this selection I would recommend you begin your research with the better known and more broadly distributed systems made by Nady, Boehringer, Shure, ElectroVoice (not to be confused the ever popular and SOTA "Electro-Vocular") and AudioTechnica. A few calls should establish whether any of their systems would meet your needs and, if you still don't understand your actual needs, they should be able to explain what those needs are once you've given them some basic information. They can also direct you to a retailer in your area.

"3" will automatically make for fewer choices, which might be a good thing. There are numerous systems which are compact and portable which could be adapted to your use. Bose, JBL, Peavey, Nady, Boehringer, and Yamaha are your best sources for this route. They should all have systems which are distributed world wide which would make them the most likely to have a universally (close to) compatible system when it comes to AC Voltage. You will eliminate the adaptability to each hotel/university sound system and only concern yourself with making the system work with the AC Voltage component. Here's a page full of portable systems for you to look at; http://www.guitarcenter.com/New-Gear.gc?internal=1&src=portable+sound+systems These aren't specific suggestions but rather just for you to look at and wonder why I put that link on the page if I didn't intend for you to actually go out and buy something just on my say so. The idea is only for you to get an idea of what you might be carrying around from country to country should you pick door #3. (Though there is a goat behind door #2 and, if I was right earlier on and you really need a new goat ... ) The focus nowdays is for portable systems to be light, compact and reliable; plug in and go to work. Few headaches for all involved.

Of course, each of the two new equipment choices I've given you will require you to travel with your own system and this might present other problems - though these are more of the headslapping, panic attack, "what do I do now?" variety should the system arrive in Coppenhagen while you arrive in DesMoine. Or you might have problems with Customs in certain locations. Here I have no good solution. Do your research and ask a few questions and then decide would be my best advice. Anyway you go there will be tradeoffs, and you have to decice which offers the most workable solution with the least amount of headaches.

As to manufacturer names and models numbers you should see that is all but impossible given the wide number of choices you have to make for yourself. You're going to have to do some of this work on your own and then weigh the advantages vs the disadvantages of each choice. But I think you should have a starting point now and enough information to go on. Finally, should you decide to opt for "2", you should put some effort into knowing a bit about what you own. You don't have to become a sound technician but you should know enough about your equipment to know when a hotel/university sound tech is blowing smoke up your skirt. Most of these guys aren't really soundtechs anyway, They got the job by defualt cause they were there the day the previous guy didn't show up. So, if you talk a good game, you can usually convice this type of soundtech to blow up their equipment for you while you call the equipment rental shop.



Good luck.




.
 

New member
Username: Healinghands33

Post Number: 2
Registered: Oct-11
Wow! Many thanks for your erudite and informative post.

I took your information on board and then called Behringer who recommended their self-contained Behringer EPA40 PA System, which is available on Amazon.com and seemed relatively small. However, in looking over the "What Other Items Do Customers Buy After Viewing This Item?" section on the EPA40 Amazon page, I FOUND THE HOLY GRAIL!

It is found on Amazon at:
www.amazon.com/Amplifier-MR2200-Portable-Teachers-Presentations/dp/B003T3Q3HE

This little bugger from Aker is a 16W voice amplifier/speaker, clips on a belt, comes with its own headset mic, and best of all is only 3.9 x 1.8 x 3.6 inches and just 10.7 ounces. Eureka! Needless to say, I have one on order already so I can give it a test. From the reviews, it seems to be a great little unit for the kind of work I'm doing, but I'll test drive it after it comes in and we'll see what happens.

Thanks again for your help; I really appreciate it.
 

New member
Username: Berniew

Perth, Western Aust... Australia

Post Number: 5
Registered: Oct-12
Hi,
I'm a live sound engineer living in Australia, and have been doing this full time for a little over 20 years. The type of thing you describe is my bread and butter. Feel free to contact me privately if you prefer, but if we hold our discussion out here in the forum, everyone might share.

For you, I would try to achieve as versatile a setup as you can. That is, you should be able to approach any venue's sound system and provide the best match to their gear, from yours. You certainly don't need to be stuck with a 3.5mm jack plug... in fact, you'll find that's considered a "domestic" format, and you'll be lucky if you can just plug it into most commercial installations. But, it's very easy to get adapters, and I make and sell custom cables, so if you can't buy what you need then I or someone like me could make one up for you for a fee. This way, you get a chance to use quality parts. By quality, in commercial applications your first considerations are durability, versatility and freedom from hum and noise.

The way to be sure you are ready to make the best connection to anything you encounter is to use some sort of preamplifier, and a small (very small) mixer is probably the best way to do that. If you choose properly, it will accept your mic, or any other you rent or are asked to use by the venue on the input side, and it should also offer a choice of outputs. That means, it should have more than one type of physical socket (you'll often find you get 3-pin XLR, 1/4" jack and RCA), and it's a big plus if it offers switchable level settings too.

A mixer also means you could add sound playback from maybe an MP3 player for some intro music, or your laptop, phone, or anything you like, maybe even your camcorder, say if you're also playing some video. It and your mic all fit in the one box, and it then feeds the in-house sound system. It should have a gain control on every input so you can bring the mic etc. in at the best level, and a master volume feeding the system, *in addition* to switchable output levels. That's because some systems will use different standard levels; mis-match them and you'll either find it hard to boost up enough to hear you, or it'll be too high, which means feedback.

Speaking of which, feedback is just awful and can utterly ruin a presentation, and distract you from what you're there to do while you try and fix it. There are automatic anti-feedback gadgets available, and with lapel mic's I'd say that's money well spent, though it's more stuff to carry around.

The mixers I'm talking about might be the size of a larger paperback book, and you don't need a lot of inputs. One for the mic, and one additional stereo input ought to do you. There's plenty on the market. In my personal experience, I've decided to avoid Behringer. Yes they're cheap, but I know music store owners and a shockingly high percentage of their stuff has to go back for warranty claims, and many stores won't stock it any more. But that' just me, you might find they offer the right product for you and you're happy with their reputation.

I do know that Mackie make some ideal small mixers, with all the features I describe, and I've used them more times than I can count without problems.

Sound guys hate using lapel mic's live. Presenters want to use them because they're inconspicuous and convenient, but they have many problems. If you can possible handle a hand-held mic, they have advantages. It's all about feedback... lapel mic's are omni-directional. All those tiny mic's have to be. It means they pick up all around and not just in one direction. When a mic "hears" itself through a speaker, you get feedback. There are two cures: turn it down, or use an equaliser, usually a graphic equaliser of as many bands as possible. I'm sure you don't want to carry around a rack of stuff, so that's not what you should get. What you want, then, is the lowest-feedback mic you can get.

Another thing: there's proximity effect. The closer a mic is to the source (your mouth), the more bass. As it moves away, bass disappers exponentially; so does level picked up. By the time you put it down on your tie or lapel, you have to turn it up pretty high to be heard. That means it's more likely to feed back, and it also picks up every little rustle and bump from your clothes and everything else. The lower volume you can get away with and still be heard, the better, and that means, get it closer to you. A hand-held mic will sound rich and full, and you can get a clear sound at much lower level and avoid feedback. Plus, they're directional, so they don't pick up sound from all around, and "hear" themselves less in the speakers, reducing feedback. There are certain models that have phenominally low feedback, and wireless models have dropped in price.

I honestly believe that a model designed to work with a camcorder cannot possilbly deliver GOOD sound; adequate maybe, but if you hold seminars, presentation is everything, and a thin, reedy, feeding-back sound is the antithesis of the look you need.

Having said that, by all means I'd be happy to help advise you on making the most of what you have. As an alternative to a mixer, you could get a mic pre-amp, which would have an equaliser and line output built in, but they'll almost always cost more than a basic mixer. The better small mixers on the market today will do everything you need, and even have an equaliser on every input to help with tone, and you can use it to fight feedback.

Remember, to a sound engineer, the limit of a live system's output is NOT the number of watts of power. It's what we call "gain before feedback" - how high you can turn it up will be limited by the point it which it starts to squeak, long before you ever run out of watts. That's how important a consideration feedback is.

If you go to you nearest large music retail store, you'll be able to view many models, sizes and prices of mixer with many features. I'd be quite happy to get involved advising on your purchase if you'd like, as I live in Australia and know the scene pretty well. I'm a sound operator, not a salesperson, so I may be able to offer a point of view about what it'll be like operating that equipment, as opposed to what a shop considers a good buy. They do music, more than they do public speaking. That sort of thing is much more specialised, but it happens to be a large part of my work.

I'd honestly look into a different mic and wireless system, something from the fully-professional production industry, for what you're trying to do. Something with AT LEAST a balanced, quarter-inch (6.5mm) jack output or preferably that plus XLR. If all you've got is 3.5mm, I can assure you you do need an adapter to fit into any commercial system. If your budget means keeping this gear, then I strongly recommend a small mixer with at least 1 mic input (minimum you'll find will probably be two, with a couple of stereo channels as well, in the smallest semi-pro mixer). That input wants to have a gain knob, a line and a mic socket, some sort of equaliser (tone control), and you really, REALLY want at least a "sweepable mid" equaliser (that is, a 3 way, not a 2-way, equaliser [EQ], where the Mid control allows you to set the frequency you cut or boost, as well as its level. So that means the bass and treble control have one knob each, and the mid control has two. It may even have a second Mid section, with a 2nd pair of knobs: again, frequency and cut/boost [level]).
Then, it needs a master level control, and it's a big plus if it has switchable master level. That'll mean a switch on the main outputs that either says something like "Mic/Line" level, or "+4/-10 dB" or even "+4/ -20 dB". In short, that means the master output (mix out) can be switched from line to microphone level, and before you plug it into a system, FIND OUT what they prefer, or what it offers. Use line level if you can, but do make sure you're not trying to connect Line outputs to Mic inputs or vice versa.

Look at Mackie, Yamaha, Wharfedale Pro, Rane, Allen & Heath, or whatever else doesn't appear to be El Cheapo rubbish. I'd advise you to avoid the lowest end of the market; you truly get what you pay for. The crappy stuff really is unreliable and really might cause you problems during the show; trust someone who does it all the time! What does it really cost you if suddenly in the middle of your presentation your system causes you problems, and you have to stop and try and fix it, and not being your field of expertise, you're not sure what to do so it's difficult, distracting and makes you unsettled and spoils your look? What will paying customers think?

You should also make sure you have the proper connections for all the equipment you use, and options to connect optimally to whatever systems you run into. Once you choose your equipment, you'll be better able to do that, but likely you'll want to connect 6.5mm balanced (stereo) jacks to either the same, or XLR's. If their inputs are XLR's, you should have the same. Be ready also to have to use RCA's: If their gear has that but your mixer doesn't, you'll need adapters. So your kit should include those. Be ready for anything; at these events you want reliability, and the wrong connections can hum or make noise, so get there early, find out what's best, set it up and TEST IT before the show. Be prepared for anything.

Well, sorry to go on and on! I'd be more than happy to help if you need to take it any further. Like I say I make and supply custom leads, connections and other gear and a lot of my work it to specify equipment for live sound productions. I'd love to know what you decide to do.
Cheers
Bernard
 

New member
Username: Berniew

Perth, Western Aust... Australia

Post Number: 6
Registered: Oct-12
Sorry, forgot to mention. Yes, you will need mains AC power for almost any mixer you can buy. Same for preamps and all the other gear, as you've no doubt noticed with your mic receiver. You'd set this stuff up off-stage wherever the venue's sound system is. At work, we sometimes get overseas acts needing to use their own stuff with different power requirements. Some can switch from 110/120 to 220/240 volts, but it also might mean you need a transformer and adapters to go overseas.
I don't know anything that would do the job completely off battery power, but I don't know every product out there.
I also don't have model numbers to hand but they change all the time. I advise you to decide what you want to spend, what parts you're willing to upgrade, then look in a big music store.
In Australia, there's plenty of mixers to choose from between say $200 to $500. Obviously you can spend more, or maybe less. But I don't think you NEED more, and I'd steer away from cheap rubbish.
If you've found feedback a problem, I'll look into products that can deal with that for you.
Would you be able to consider a hand-held wireless mic, in order to get the benefits of a richer sound (by holding it right up close to you) with little or no feedback, or do you really need to use a lapel mic? If you can go hand-held there's plenty of choices. The same belt packs and receivers will accept lapels. A hand held is the transmitter itself and needs only a receiver, not a belt pack. I'd say something up to your needs, with the mic and wireless system complete, could be bought around the 500 or 600 buck mark, give or take a bit. You COULD do with less; I just always recommend quality.
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