“Monitors, loudspeakers, P.A.....the mysteries unravelled!"

I, for one, have been befuddled [is there such a word?] by the 'black-art' of speaker making, speaker listening and most of all speaker purchasing.

Oh, I know all the basic stuff, but I could never figure out why a Meyer, mega expensive, totally professional, touring sound rig sounded so different to even the top of the range P.A. speakers available to the general masses. I actually gave up even trying to figure it out and just based my judgement of speakers on the speakers being Industry Standard for the job and then powering the speaker/speakers with the biggest amp. I could afford at the time.

As it happens, that theory is about correct. And through the years I have understood enough to know that :

Good Speakers + Big amps = Good, Correct Sound.

But why? Surely a 100 watt speaker should be driven by a 100 watt amp?

Nope! I found there were a number of reasons why.

1) If you drive that 100 watt speaker with 100 watt amp then if you want [or more importantly the DJ who hires/borrows your gear] wants more loudness and particularly 'bottom end', by winding up the low EQ, then the amp. will clip. In other words, will shut down to protect it's own circuitry. Now - picture the speaker slamming in and out thousands of times a second....then all of a sudden, no power...so the speaker stops in a millisecond. Then a second later, the amp switches itself on again....WHOOOOOOWWWWWW! The speaker will just rip itself to pieces.

I then understood why Hire Companies will typically supply amps that are 5 times the rated power of the speakers. For their own protection, is the answer.

No clipping = no bust speakers!

Well almost.

2) Using powerful amps will mean that the speakers will operate with incredible efficiency. But what if the inexperienced acoustic guitar player decides to plug his guitar into the D.I [direct injection] box on stage and not tell the sound boy? Have you ever seen the way the sub woofers move when that thump, electrical sound, hits 'em?

Aside: As a courtesy never plug anything in on stage without telling the sound boy...he will love you forever.

Those clicks and thumps will certainly rip speakers to bits.

So back to the wattage of speakers:

The rated power of a speaker is the amount of wattage needed to move the coil of the speaker.

Wow! When I heard that I started to understand. Now I knew why 5,000 watts made a 1,000 watt speaker cabinet sound so good. A 1,000 amp would just barely move the coils!

So what else did I have to know?

Why are some speakers 'louder' than others? Now - that is a mystery to me...too technical - but I learned that the important part of the speaker description was the SPL quoted. That means Sound Pressure Level. Or to you and I the 'loudness' it will deliver.

Normal, good quality, Hi Fi stuff in your home will be excellent if it delivers 85DB [Decibells]. But a high SPL professional speaker will deliver 127DB-135DB.

The figures start to get crazy and an expert will tell you that each 3DB will effectively double the volume...but that's gets highly technical.

So what do you look for in comparing speakers?

The frequency range for a start. NS10's are the Industry Standard all over the world as a reference speaker for close range monitoring in studios. They have a decent SPL but only deliver sound down to 60Hz [Hertz]. So you won't get a lush bottom end from Yamaha's.

Why are they Industry Standard?

Because if you get a mix right, that sounds exciting and smooth, on NS10's then that mix will sound brilliant on higher spec'ed speakers...understand? That is why we use them.

If you want High SPL, coupled with a full range of say, 35Hz up to 20KHz then you have to spend the dosh...there is no other way. And the flatter the response [meaning that they deliver the same volume over the full frequency spectrum] the more you will pay for those speakers. you really should check the response graph of any speaker you are thinking of buying. It should be almost a straight line from 35-25,000Hz. That is what to aim for with the available cash.

What to aim for in your studio?

You need those ubiquitous Yamaha NS10's, if only for the fact that your mix will then sound the same in your studio, in the mastering studio, and then in the A&R Department of that Record company you are hoping to do a deal with. They will also add a 'professional' air to your set-up.

You also should have those expensive High SPL jobbies.

Again, so that you will know that your mix sounds phenomenal when driven hard and drawing blood from people's ears. It, specifically, will show up too much bottom end....a common fault of amateur mixes.

It is wattage that gives big bottom end - not the EQ knobs!

You should finally have a crappy boom box rigged so that you can check your final mega mix on the stuff the kids will play it on....make sense? You can burn off a quick CD and check it out on that sort of cheapie music machine.

Oh by the way....

Which power amps?

Don't even think of skimping on this more important part of your studio. Do NOT use Hi Fi separate amps...they are designed for home Hi Fi and will give a 'colored' sound and not the flat sound that our speakers are capable of delivering.

My Advice?

Buy the most powerful [and I do mean the most powerful] power amps you can afford. Be aware that the biggies are fan cooled and should, therefore, be outside the listening area...very important. Use the best quality speaker wire to trail from the amps to the speakers [best speaker cable is currently available from car sound accessory shops]. I would suggest a stereo amp capable of delivering 1,000 watts into 8ohms.

Now over to a real expert.....

One of the Members of 'The Serious Writers Guild', Ian Warrener, has become a major force in speaker design....his advice is sought by a lot of the 'biggy' PA companies....he sent me this short article...you will love it. Ian speaks the only 'logic' I have ever heard about speakers....stuff that we can understand...I also use his latest design as my main monitors in the studio....AWESOME!

'IMPEDANCE'...the mystery revealed:

The Resistance of each Loudspeaker drive unit and the way they are wired together are the things we need to calculate overall 'impedance' which translates as the 'LOAD' exerted on the amplifier, just to confuse things 'AS THE IMPEDANCE INCREASES SO THE LOAD ON THE AMPLIFIER DECREASES' and in turn 'THE LOWER THE IMPEDANCE OF THE CIRCUIT THE GREATER THE LOAD ON THE AMPLIFIER'. Many modern amps will run at 2 ohms (some even 1 ohm) but that doesn't mean that it doesn't have consequences and knowing the way the overall load is calculated can help with adding flexibility to any system.

Firstly, all loudspeaker loads are NOMINAL this is a figure used to represent the way IMPEDANCE changes with frequency i.e. A nominal 8 ohm load although undoubtedly 8 ohms at some frequencies will be very different at others. Use the nominal figure for calculations

There are 2 basic ways to wire up multiples of anything, either in SERIES or in PARALLEL, or a combination of the 2. In a series circuit the signal is fed from +ve (of the amp output) to +ve on first speaker (either box or driver) then from negative on first speaker to positive on 2nd speaker, negative on 2nd speaker to positive on third and on and on until negative of last speaker goes back to negative on amp.

Wired in this way the overall circuit impedance is raised and the impedance of each unit is added to give the total load i.e. 3 x 8 ohm speakers wired in series 8+8+8 = 24 ohm load, 5 x 4 ohm speakers 4+4+4+4+4= 20 ohm load.

In a parallel circuit all positives are wired together as are all negatives, positives to positive on amp, negatives to negative on amp, wired in this way the overall impedance is decreased, to find the figure we need to do sums though.

Here goes:

If x = final circuit impedance and (for now) all loudspeakers are 8 ohm

Then

1/x = 1/8 + 1/8 + 1/8 +, etc.

So with 2 speakers 1/x = 1/8 + 1/8, so 1/x = ¼, so x = 4

But with 4 speakers 1/x =1/8 + 1/8 + 1/8 + 1/8, so 1/x =4/8 =1/2, so x =2

As the amp used may produce double the power at 4 ohm that it can at 8 ohms it is useful to know these figures and by using combinations of series and parallel networks it is possible to wire many loudspeakers onto a single amp (power permitting) without overloading the outputs (check amp spec for minimum load impedance). But always check overall loading and remember the lower the overall impedance the harder the amp has to work the hotter it will get, the higher the overall impedance the lower the distortion and noise of the final sound.

SMALL ROOM PLACEMENT OF LOUDSPEAKERS

First let us look at wavelengths.

A low frequency signal has a LONG wavelength. In rooms smaller than the longest waveform produced by the loudspeaker this will cause coloration of the "perceived" signal in the form of compression and rarification of sound waves as well as reflections within the room and can cause "hot and cold spots" where volume is much higher/lower as well as frequency peaks and troughs caused by cancellation/re-inforcement of the sound wave.

As a formula F= 560/d where f@-- frequency and d= longest room length.

So a 46hz waveform is 12ft long

A 30hz waveform is nearly 19ft long

A 20hz waveform is 28ft long

To minimise the effects of the above principles and make the most of true stereo imaging first choose an acceptable position for the loudspeakers with the longest distance possible between them and the opposite wall and again with the prime listening position being set as far back as possible from the loudspeakers.

Many books will tell you then to immediately "toe in " the speakers towards the listening position and a very slight (5 degree ) angle can be beneficial in decreasing reflected signals - but be wary of increasing the angle too much and under no circumstances should both speakers be pointed straight at the listening position (only ever necessary when loudspeaker polar response/distribution is inadequate) as this will cause major Nulls and Peaks particularly in the 200-2khz range and ruin any stereo imagery evident in the initial recordings .

Keeping the angles of the 2 speakers slightly different will also cut down the effects above as will dampening any reflective wall surfaces and minimising or damping contact of the cabinet to the surrounding surfaces whether wall or floor mounted.

Don't be frightened to experiment but take the time to do it gradually and listen carefully at each stage - noting any changes you may notice, especially the small ones.

NEW DRIVERS - INITIAL PRE CONDITIONING

ALL new bass drivers will show a marked lack of low bass response before pre- conditioning. Pre- conditioning will vary with coil size but take this as an advisory "Running in period".

A good rule of thumb is 4 to 8 hours for each inch (diam) of voice coil ie. 2" voice coil min = 8 hours

or

1-2 hours per 100watts of programmable power rating

ie. 600w rms driver = 1200w prog = 12 hours min.

Before this the drivers parameters will not be accurate and gentle handling will not only improve FINAL performance but will increase driver life dramatically by 'Bedding in' all moving parts.

During Pre-conditioning period treat driver Power rating as 1/4 that quoted and increase to HALF full rated power after 1/2 calculated preconditioning period.

[written by Ian Warrener....]

Totally endorsed by Dec...as the only one to speak the truth about speakers! buy from him with 'assurance'.

Check Ian out at www.pa-direct.co.uk

Typical Question from Members of my 'Serious Writers Guild': "From your experience, what is the easiest way for me to become a star?"

Answer:

My simple answer is to become a Member of 'The Serious Writers Guild' CLICK HERE

Best Regards

Dec......

dec@makehits.co.uk

Become a Member of the 'The Serious Writers Guild' CLICK HERE When you get involved with DEC you get the first program: "How To Make A $Million From your Music" - ten months of two knowledge packed books a month, songwriting tips, stunning advice, today's methods for writing music, making music and promoting it. 24/7 access to the man himself. And you get a 'LIFETIME' guarantee. If you ever pay DEC for anything, if you are not happy at anytime in your life with the product then return it for a complete, no-quibble, courteous refund! DEC means it! That's not only a guarantee it's a personal promise "There Is No Catch" "There Is No Risk" Become a Member of the 'The Serious Writers Guild' CLICK HERE

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