Optimum page rez 1080/720p
Playroom Schematic 2013
TOYZ 2 PLAY WITH !!
MXL990 u47 mods performed by John G0TIY ( my audio mentor ), John is completely dedicated to audio,
heres one of his projects which i pinched off him to use, love you John !
above: Standard MXL990, small Standard capsule, pcb, and components.
below: fully modded MXL RK47, everything upgraded to finest quality
real nice job John, mic is silky smooth and as flat as a pancake !
Please No Lidz......
When on lsb phone, I will not respond to cw abbreviation,
Break Break, or any CB talk. THIS IS NOT CB.
Please be human, and respect ham radio for its preservation.
( my concern is the clubs that teach, or dont in this case )
160FT DUBLITT @ 40FT / 450-OHM BL
Skyline Sound Diffuzer, Active between 750hz-6khz
GET ROUND TO IT'Z:
- bird nest cam outside shack filming swollows (Mick n Jan) for springwatch *update= 5 babyz all healthy and noisey!
- Got all materials and genuine plans, started building the taylor titch aircraft, updated some machinary.
- Patio @ sisters house now complete, decking area also completed.
- shack acoustic treatment continuing, 20 QRD diffusers to be cut and assembled ready for installing.
- 140 metres of timber used to build 6 skyline diffusers, in total 830 blocks, software modelled for 750hz to 6kz diffusion, completed.
- RGB 5050smd led skyline lighting......done!
- 2 x bass traps using owens ridged glass, and owens softy. 15" square from floor to ceiling for rear wall, unique waveform inserts, completed.
- 24 x 18" acoustic tiles 80mm thick, for main reflection points, installed, completed.
- pyramid diffusers for ceiling now completed.
- 6 x full range sound traps completed.
- Door sound block panel, completed.
- Q acoustics now up and running.
- 55" 3d led monitor to replace smalls, complete.
- Vinyl collection now well underway, just picked up lots of white label rares ...." BIG UP THE MASSIVE " .
- Vinyl cleaning machine now built and working.
- Homebrew vinyl cutter, design nearly complete.
- 5751 gec (cryo's) jan tubes now installed, audio gear tweeked to suit.
- Remote android station now fully operational via net, full control all radios/audio/tuner.
*** PLEASE DON'T "HERT" ME ! ***
A small note to anyone with a negative attitude towards those that experiment,
You cannot and will not achieve HIFI tx audio unless the tx bandwidth is that of the human ear,
this is very possible with flexradio etc but not very friendly to other band users.... hehe!.
You can however achieve the same natural shape curve, using a smaller sound spectrum ( 50hz - 3.5khz ).
Most men over the age of 50 have a very limited dynamic range, making the above figures ideal.
More or less every modern day reciever is more than capable of hearing your tx bw.
The amounts and octaves at which we eq is very important and largley missunderstood by many.
The high end energy at 3.5khz is perfectly ok if eq'd correctly,
and can be balanced with the lower regions to create a normal graph profile,
thus, giving a much more pleasing and clearer sound for others to decipher.
Tubez in use on TX
Radio Control Software
HOW DO YOU SOUND? OPEN OR CLOSED?
A small intro into the subject,
Many Ham operators are completely unaware of how there transmission sounds,
and many depend on others to give so called accurate audio
reports, of course by doing so we are unaware of how the person is rx-ing you, the equipment
they are using, there own preference and any hearing defects they may have.
There are so many variables, its more or less impossible to get an accurate comment,
you ask 10 people and get 10 different reports resulting in more confusion and being
worse off than when you first began.
As an operator, we are in control of lots of buttons, most of which will affect the way we
sound and how the station performs in terms of clean transmission.
I also believe any station owner should take time to clean up there transmissions and
understand exactly how to use there equipment, doing so will result in many rewards.
There is nothing wrong with using a standard hand type microphone if your not fussy,
however if you do wish to improve things for others then the journey can be quite long and
frustration can set in, so take time to decide on whether this is for you and how deep into it
you wish to go, it can be very expensive once the bug sets in, but the improvements that can be
achieved are quite astonishing!!!!!
Due to such a large amount of equipment being available on the market for audio use,
the world really is our oyster, and the selection of devices you could use is endless.
So hopefully this small guide will help you to choose your audio gear and get it on air,
using it to an accurate and pleasing standard.
SORT YOUR AUDIO OUT!!!!!!
Now for the nitty gritty!!!!!
TX Monitor radio
The first place you should start is with the monitoring receiver, which you'll use to monitor
your own tx audio in real time over the air conditions.
Its absolutely essential that the receiver you choose to perform this task has an accurate
flat rx audio response with plenty of bandwidth, capable of hearing your transmission and way past
if possible, to ensure what your hearing is the full content.
There must not be any restrictions or colorations from any devices.
For those that don't know what a flat response rx is, in figure 1 you'll see how a flat rx looks
compared to the average response found in most blackbox type radios.
Anything other than a flat line is coloration from the receiver, and this of course can give
a misleading reproduction when monitoring and setting up your tx audio, almost like different
people have different tastes.
Working to a standard ensures the audio balance is correctly set to a neutral ground, meaning
peoples preferences and different equipment in use doesn't create problems for us,
however they wish to receive you is up to them!!!!!
STANDARD COLOURED RX
Using a flat rx monitoring station is the most important part to achieve this goal to the best
of standards, along side a PC running Spectraplus audio analysis software this software is
available in full to any ham audio enthusiast for free due to a very clever keygen (thanks guys hi)
This software will be used in conjunction with the monitoring station to view, adjust, compare and
balance the audio coverage out over your tx bandwidth evenly and to a natural response shape
like that heard in real life. Many tasks can be achieved by the use of this software
far too many to list, but its proven to be a vital tool by all that use it over the years
(and thats everyone into tx audio pretty much!!!!!)
And of course the PC has no preferences, but simply displays whats there.
To date still one of the best receivers for this job is the Kenwood ts870 made between 1995-2005,
the rx audio response is completely flat from 20hz-6khz making it the ideal tool to monitor your
transmissions, its completely natural and has no colorations what so ever, so whatever is there you'll
hear and to an exact reproduction standard.
Theres is other options for those that don't wish to spend the money on a dedicated monitor radio
such as using someone elses over the air, but this can be very difficult to undertake accurately due
to band noise/conditions and only works providing your signals are at max strength to one another.
By use of the email system or Skype we can send each other the recordings/graph readouts etc, but is far
better if you can do it yourself as it can take some time to get right.
In figure 2 you'll see how to setup your monitor station. A very simple task to complete taking no more
than a couple of minutes and providing you use the correct equipment it will solve the problem of
personal preference from on air reports, which of course you'll be fighting forever.
The other part of your monitor station is the headphones, again many brands offer very bad sound
quality and the reproduction is far from flat or natural. Canz or headphones are used to listen to the
monitor station so its equally as important that these are also a flat response and have as little coloration as
possible,the more coloration or sound tailoring they have the further away from accurate your
monitor station will sound and as a result of this your audio will always sound different to what you
see on the Spectraplus graph, creating a problem with dominant frequencies and accurate corrections.
When buying headphones, look at the specs and try to find the flattest response curve you can. The largest
drivers too allow for a more accurate coverage so look for 40mm in size, also look at the frequency
coverage and try to find those that have a total coverage from 5hz to 20/30/40 up to 80khz in dynamic range.
At all times trying to maintain that same level of accuracy throughout the chain for as near as possible
real life reproduction.
Headphone amplifiers must also be used to drive the canz correctly. Standard headphone outputs
usually lack alot of accuracy in many ways, but one way of combating this is to use a wide dynamic
range amplifier, ranges of upto 100khz can be achieved with these little beauties and as a whole bring
the canz to life in every way, shape or form.
Here's a pic of my headphone amps.
Again figure2 shows the connections for the monitoring station, once you've got all gear up and running
the next step is to set the monitor radio correctly for best results and accuracy, different radios can differ
slightly although usually these settings should be ok for most modern radios, for very close reception at
Always use attenuation to prevent the front end from being overloaded not doing so may result in major damage!
start off with max attenuation and back it off if necessary,
turn agc OFF
Back rf gain control down until s meter reads around half deflection or at the point at which the noise floor goes quiet
use a small 12 inch piece of wire for the ariel in ant socket 1 for low power tx monitoring,
use a pl259 plug in ant socket 2 with the inner conductor and outer plug body shorted to decense the receivers sensitivity
to monitor high power tx signals ie: checking your audio with an external linear amplifier running
at high levels, to check station stability and determine any problems or weak links within the audio chain,
just remember to switch over when needed as this can be an expensive mistake to make.
Also, any transmissions will be made using a dummy load when monitoring your own tx.
Figure 3 shows shorted pl259 connections for qro monitoring.
Ok, thats pretty much all there is to the tx monitor setup although there
are even better ways of doing it for a greater cost, such as better sound cards
and many different types of audio connections aswell as digital conversions
at high sample rates etc, fibre optics, better PC processors for higher resolution
of audio readouts etc...the list goes on but for now this basic method is more
than enough to get you going and at a good level.
TX/RX Main radio
The next thing comes your Tx station and its audio connections via various
pieces of equipment, again the radio of choice must also be chosen very carefully.
The tx audio must be of a natural sound, though this is not necessary as we can eq
for any problems. There are a few radios available at reasonable cost, the most popular
for a nice tx sound are as follows:
- Kenwood ts950sdx (not sd model) :best quality for tx audio @ 20hz-6.7khz bw
- Kenwood ts870 (later models) :also a very good radio on tx @ 20hz-3.8khz bw
- Yaesu ft5000: very nice sound on tx @ 20hz-4khz bw
- Yaesu ft2000: very nice sound on tx @ 20hz-4khz bw
- Yaesu ft950: really nice smooth sound @ 20hz-3.2/?khz bw
- Yaesu ft1000: slightly more restricted @ 80hz-3khz bw
- FlexRadio Systems: very good but different @ 10hz-20khz bw
- Apache Labs sdr: slightly smoother than the flex range @ 10hz-10khz bw
- Icom ic7700: not as smooth, also restrictions @ 50hz-3khz bw
- Icom ic7600: very good contender but still restricted @ 70hz-3khz bw
- Icom ic756 pro models: not bad, but too many restrictions @ 100hz-2.9khz bw
- Kenwood ts990: very good but still not a patch on the 950 and 870 @ 50hz-5khz bw
- Kenwood ts2000: very good for vhf fm audio work @ 20hz-3.6khz bw
- Kenwood ts590: very bad, audio stability issues, alc/drive issues, drifting and worbling @ poo bw
The Kenwood ts870 is flat as we've already mentioned, also the sdr type radios are quite flat,
all other radios on the list need modifications to perform a flat rx.
There is of course many other radios which have a nice rx sound but they are getting harder to
find day by day as people snap them up to do there audio related radio tasks. There
is lots of info on the internet, I'm sure you'll make the right choice, if you need any help please
feel free to email me with any questions you may have, I will always do my best to help.
So as long as you select a radio thats suitable, the battles already half over. Many Hams
make the wrong choice of radio and of course as a result they never get the desired results
and usually end up very disheartened, so making the right choice is of most importance, again
feel free to ask any advice on transceivers.
The Audio Connection
Then, of course comes the audio gear you wish to use and as mentioned before the list is endless
to what equipment you may choose ,again as with all parts of this project you must select the correct
units to use, those more suited to radio, eq/dynamics and the effects they have on tx audio.
Many studio rack mount components can have little or no effect, so be sure to pick the essential parts
first and worry about the silly bits later, The most important audio units to use are as follows:
A good quality full frequency range microphone also with a more or less flat response,
such as a high quality dynamic mic like the Electrovoice re20,
or a studio condenser microphone. Dynamic mics don't require a power source so can be plugged
directly into a mic line input, and increasing gain until 0db levels are achieved.
However most studio condenser mics require high voltage to power them, if you do choose to use
a condenser mic you'll more than likely need to supply it with 48volts, but most mixer/pre amps etc have
onboard 48v supplies built in, which are switchable if needed, so theres usually no need to worry about that.
Any advice you need on microphone selection please email me and I'm sure it will be a simple choice to make,
the mics with best sound are those made by rode microphones, Electrovoice, Akg, Neuman, SE and many more.
There is of course a big difference in cost as the quality increases, but theres also lots of mics available
for a very reasonable price starting from 30pounds and of very sufficient quality.
The next piece you'll need will be a pre-amp to drive the mic, sometimes known as channel strips these
are widely available for very little cost if thats how you wish to go, but again the quality will affect the way
the microphone performs so its always a good idea to buy the best you can afford. It would be a shame
to have a nice mic and let its sound quality down by driving it with a poor pre-amp.
Popular brands of audio gear, in the budget range=
- Studiospares own brand
- and the higher end brands=
- TL Audio
- Thermionic Culture
These are just a few companies that produce the types of units we can use for tx audio.
They are used mainly for studio recording applications, but are also ideally suited for Ham-
radio use. Always buy metal cased units and use heavy cable shielding, this will ensure your systems immunity can thrive.
The next unit you'll need is the equaliser but not a graphic eq, this would be useless.
The type of eq we need is a Parametric-equaliser, the differences between the 2 types are:
graphic eq's have pre set frequencies at fixed octaves, where as para eq's have adjustable frequencies and
adjustable octaves giving us the ability to concentrate on the actual frequencies we may need
to tailor for our personal voice, every voice is different, so frequencies may vary widely.
With the use of a parametric eq we can target exact frequencies and adjust octaves to
suit a particular voice pattern. You may not need to eq many frequencies and most areas
you do eq are usually cuts not boosts.
To create balance we need to cut frequencies that are dominant or unbalanced, bringing them
down to a more suitable level as to blend in with the rest of your tx sound spectrum.
Trying to recreate a natural curve in such narrow bw's can be tricky and theres lots of tricks
to getting it right, help and advice goes along way if you've never done this kind of thing before,
but theres always lots of guys available for advice if you need it!!!
Once you have your eq up and running many tests must be done including:
direct mic response
determine which freqs are a problem
para eq adjustment to suit
and of course your monitor station will provide you with all the information you need.
Pics above show my mic, pre-amp and parametric eq, for use on tx audio.
The next series of graphs are all of my radios on rx at max bw,
I also use many other devices inline to get my own personal desired effect,
however with these 3 items you could achieve pleasing enough results.
Of course some adjustments will be required so take your time to pick the
correct frequencies for your voice. Starting without the eq to see where the problems lie,
then engaging the eq to correct those problems.
All the time referring to your monitor stations graphs readouts to see exactly
whats what. Software can also take time to master so take time to learn the basics
of the software user interface.
VERY IMPORTANT PLEASE READ!!!!
This is another very important piece of equipment you must use at all times,
this is the audio isolation transformer, placed last inline on the audio chain to correct
audio signal levels, eliminate loop hums and of course isolate your transmitter from
the rest of the audio chain.
The most common form used are Direct injection boxes or di boxes,
these do all the said above and insure safe and correct use of the equipment.
Di boxes are a very simple audio transformer that can perform a number of tasks
depending on your connections, layout and requirements.
The range available is quite large so I would recommend you contact me for
more details and to find what's best suited to your operations (email addy on top of page)
The functions of the transformer is as follows:
If your feeding the audio into the front mic socket you'll need to reduce the line level
source down to a comfortable level. Most front mic sockets are designed to work with a hand
or desk type microphone working at around 600 ohms.
If your feeding the audio into the rear audio input sometimes found within the acc
connections or dedicated line level input, this will work at line level so theres no need to
reduce the levels from your audio equipment.
Feeding into the back audio input is always recommended for a better, clearer response,
bypassing the radios mic pre circuit on the front mic input stops any coloration
from the radios microphone amp stages, resulting in a more open sound and sometimes
a much better response.
Front mic sockets have a tailored sound response for basic comms operation. So boosting
mid range frequencies to make things distort and sound horrid is usually the case,
so to bypass this is always a good thing, the rear audio input sends audio direct and
uncolored for much better results overall.
ALC becomes alot nicer to control when using the rear audio input, so all those nasty
audio peaks become tamed and the ALC works no where near as hard.
Some radios require a very simple modd to use the rear input, but most radios do not.
If however you are unable to connect the audio chain into the rear input, you can use the
front mic socket but will need to reduce the signal level as mentioned above by the use
of attenuation switches on the di-box, the most common amount of reduction here is around
-30db and this of course is about right to convert your line level to mic socket 600ohm
Again feeding into the back doesn't require a drop in signal so all attenuation can
be left alone and things will be fine at line levels, the audio transformer then is only really
used for isolation, which is equally as important.
The most common problem I come across on air is incorrect levels and usually no
di box or transformer, so incompatible levels and rfi problems due to earth loops or
Here is a simple passive di box, the same one as I use for my tx audio connections,
they are not cheap if you want quality, but the importance outrules any justification
Standard passive di-boxes are far more convenient compared with active units.
I also use this type for individual rack component isolation
Again read the specs when purchasing a transformer/di-box insuring there is no
restrictions in the audio path, So a full sound coverage is needed again to a flat response,
and the widest dynamic range available, the di-box in this pic has an audio response
of around 8hz-40khz so anything going in surely comes out the other side. Many transformers
can have cut off points or drop offs in frequency response, avoid this type.
Check the specs to make sure its flat and wide !!!!!!!!!!!
Heres a pic of my tx di in place on the stand.
Please don't hesitate to contact me with any queries regarding isolation transformers,
and the connections that need to be made.
Optimizing Your Audio Signal
Ok a small note on adjusting your transceiver for optimum performance....
also a very important factor when aiming for the highest quality,
lots of people do not use the ALC reading correctly and due to this they overload the audio
input stages and in turn sound horrid, care should be taken when adjusting the drive control.
ALC stands for auto limiting circuit and this feature basically tries to stop the operator from
overloading the audio drive/input, cutting back on peaks it tries to even out the average speech
pattern and create a better and smoother average talk power. The ALC should be used as little as
possible in most cases, bearing in mind its a limiting feature so it cuts back on excess audio drive,
once you've reached your audio input optimum with max power output you cant get any more
out of it so its totally pointless driving it past that point.
The ALC should read a quarter scale in most cases only on speech peaks from time to time, a constant
reading means constant limiting is being applied and so indicating the drive is too high,
A nice gentle rise in deflection from time to time is about right, but only peaking around
quarter scale on the ALC read out.
Even though ALC is designed to limit, excessive audio drive levels will override the ALC and put
the transmitter into complete distortion, and thats not good.
Another feature of modern radio's is onboard audio tools, such as eq's, compressors etc,
many of them do work ok, but for what we are doing the radios features are all bypassed.
If you want to do things accurately your far better to do all the audio work externally.
Another quite horrid feature of most radio's is the dreaded processor button.
This is surely the worst thing known to man for spoiling perfectly good audio.
All this feature does is boost midrange frequencies to the point of distortion. hmmm!.
Make sure all radio audio features are off and bypassed, then superglue the buttons,,,,yak!!!!!!
Setting up your mic and pre-amp
Once all of the connections are made and your ready to go youll need to setup your mics gain,
this is done by the use of controls on your preamp or mixer's mic intput.
Depending on which mic you choose the levels will differ, the aim is to optimize the mics
performance and the levels at which it operates.
Start off with all gains set to the "0" or 12 o'clock position, whilst speaking into the mic
and checking the input/output VU meter's insuring the "0" db level is not exceeded, going past
the zero marker will introduce noise and very high peaks in drive levels.
This is the first piece inline so any unwanted artifacts created here will go-on to the next piece
and generally spoil the whole exercise.
Once youve achieved the correct levels your ready to move onto the next peice of equpment,
like the pre-amp all audio equipment must be setup correctly, if input/output levels are incorrect
you will introduce either distortion or a rise in the audio's noisefloor, this is not ideal.
Personal voice pattern
Before you engage the eq, you'll need to work out your own voice pattern/response curve.
Speaking into the mic whilst monitoring the Spectraplus display screen, use a test speech
to determine where any peaks or dips accure within your voice, this will indicate where eq
needs to be applied.
And it goes without saying, any dips can be raised and any peaks can be tamed.
I personally dont like the flat response sound on tx audio, going for a flat line response
removes all life from the sound, so like me you may need to maintain some shape,
but of course the correct shape like that heard in real life.
Hints and tips for eq'ing correctly.
Depending on the eq you have things can be slightly different during the setup
procedure, but mostly the settings are all very similar, so these few hints n tips should
be an ok starting point for most.
Your eq is designed to work with a full sound spectrum, meaning its primary
intended use requires at least 20hz-20khz full sound spectrum, for an exact real life reproduction,
however on tx we use a smaller portion of that spectrum, due to the nature of Ham-radio
and its narrower bandwidth operation.
We can however, with some tweaking get the most out of that narrow bw by pushing the dsp skirts
to the max, this will ensure your transmitter is performing to its maximum potential,
with the use of octave/Q controls we can push the dsp edges as far as possible but without
degrading the dsp's sound quality. This is why we use parametric eq's and not just regular eq's.
Take your time to look at the next pics, here are 2 identical frequency cuts, the first with a wide
octave/Q and the second with a narrow/steep octave/Q.
This is the reason why we cant use regular graphic eq's, we must have full control over how
each cut/boost effects the mix, as mentioned before you may not need to eq many frequencies
but what you do eq needs to be presice.
Looking at the graphs above, we can see the effects Q can have on our adjustments.
Usually the Q is set to a narrow position when using narrow tx bandwidths, but dont be affraid
to experiment with your settings, some frequencies may need more Q to get the desired affect
compared with others.
Start off by eq-ing the high frequencies, then the mid section and finally the low end.
Doing this will allow you to hear the overall mix better/cleaner, the low end is very thick and will fill
the mix to soon and as a result this makes corrections harder to dectect and make,
so start off with the highest/lightest frequencies firstly and working your way through until you
reach the lowest/thickest.
Common fundamental male voice frequencies to cut/boost are as follows:
- 50hz-70hz my voice is @ 60hz
- 100hz-125hz my voice is @ 120hz
- 140hz-180hz my voice is @ 163hz
- 250hz-325hz my voice is @ 280hz
- 500hz-525hz my voice is @ 520hz
- 800hz-1khz my voice is @ 850hz
- 1.5khz-1.8khz my voice is @ 1.6khz
- 2khz-2.2khz my voice is @ 2.1khz
- 2.8khz-3khz depends on tx bw
- 3.5khz-4khz depends on tx bw
- 5khz-7khz super wide oh yeah baby!!!!!!
- 10khz-20khz he he!!!!!!
All of the above freq's are cuts for my own voice, apart from the lowest and the highest,
but again it may vary so be sure to find the frequencies which have most effect on your own voice.
How you use these cuts/boosts also depends on what other audio gear you have in the chain.
Set your monitor radio to full rx bw,making sure its wider than your tx bw.
When eq-ing the high end you'll need to determine where your tx bandwidth reaches, to do this
simply set a boost at a high freq with a narrow Q, bringing the frequency down until its within
your tx passband then opening the Q back out slowly, for example: on a radio with around 3khz tx
bw use a 4khz boost and bring the frequency down slowly until you hear it on your monitor radio.
Once youve reached this point, increase the freq slightly and Q,
Doing this will insure your getting the most out of your tx bw therefore making the most of your sound.
Most male voices need a very servere cut at around 160hz with a Q of 2 octaves to clean up the lower section and
create seperation, without doing so the sound is very muddy and wolly but do experiment between
140hz-180hz as voices do vary depending on pitch etc. This is the most important cut of all.
And remember any changes you make by the use of cuts or boosts will have an effect on the levels
throughout the chain including most of all your radio's audio drive and the ALC.
updated when possible thx.