Check List #1: Is your mix final? Has it already been approved by the concerned artists and recording producers?

Purpose: If you create a mixdown, the final approval is done by the artist and the recording producers. You need to make sure that there is no other request for changes from them in the mix, it is because once the material will reach the mastering studio, there is no turning back. If you turn back, you need to do a separate mixdown again with the artist/producer requested changes that can take time and destroy your schedule.

Check List #2: You SHOULD mix down to highest audio resolution as possible.

Purpose: You need to create a very high quality mix, isn’t it? If you mixdown to low resolution such as 16 bit 44.1Khz (by applying dithering for example), you are destroying your mix.

Do not apply any dithering during mixdown. Leave that to the mastering engineer. Also if your audio mixing software/DAW is capable of mixdown at 24bit 96Khz (common in most professional studios), then use it. After all that high resolution will be VERY favorable to the mastering engineers when they do the mastering work of the track.

The minimum bit depth should be 24 bits (you should never mixdown to 16 bits, ever!). The sampling frequency can be 44.1Khz, 88.2Khz or 96Khz. Using 192Khz is not recommended and neither it is beneficial in contributing to the sound quality. But again, 24 bit, 96Khz or 24 bit, 44.1Khz are the standards.

Check List #3: The maximum amplitude of any wave in your mixdown audio tracks SHOULD not exceed above -3dB.

Purpose: By allowing or setting a maximum amplitude of -3dB, you are giving the mastering engineer a lot of headroom, which is very important. Remember that by doing this, a lot of headroom can mean less distortions after the audio mastering job and better sounding track.

You can use your audio mixing software to measure the maximum audio amplitude of the mixdown track. Bear in mind that maximum audio amplitude is DIFFERENT from average audio sound level (SPL).

It is because maximum amplitude is the maximum recorded peak of the mixdown signal. See screenshot below:

Check List #4: Never , ever compressed your mixdown in an attempt to make it LOUD and at the request of your clients.

Purpose: By compressing to make it loud in an attempt to praise clients or it is a client request, you are destroying your mix which is IMPOSSIBLE for mastering engineer to repair and restore its dynamics in natural way.

Educate your clients that it is the mastering engineer job to make it VERY loud. If they need to hear what is sounds if it is loud, simply turn the volume controls (of your studio console) to maximum without altering or applying any compression to the wave.

Some very important things you need to know:

a. length x = length y = length z , so it means that x , y and z formed an equilateral triangle.

The purpose why this should be an equilateral triangle is for optimal stereo listening. Of course, you should point the monitors to you in such a way that it forms a triangle like what is shown in the above screenshot.

b. The optimal length e can be calculated as: 38% x length h. length e is the distance from the engineer to the wall facing him. The reason for the 38% is discussed here thoroughly: http://www.realtraps.com/art_room-setup.htm

c. The blue colors on the corners are the “bass traps”. The overall purpose is to absorb low frequencies and to prevent reflections which will distort the “real” bass sound level.

d. The green are the sound waves reflection absorption panel, Their main job is to absorb mid range to high frequencies.

If this room design will be implemented, what will happen is that the undesirable standing waves or reflected waves will be drastically minimized. Thus the only sound in the room should be coming “exactly” from the monitors and does not include the reflected waves.

Finally, since what will come out of your studio monitors are exactly what you will hear, you can used this to create a fairly accurate mix that will translate to various hi-fi monitors or even a normal speakers.

For placing subwoofers, you might refer to this following tutorial:
a.)http://www.soundonsound.com/sos/feb05/articles/studiosos.htm
b.)http://www.gearslutz.com/board/rap-hip-hop-engineering-production/197461-where-do-i-put-subwoofer.html

So in summary you need:
1.) A nearfield monitors that are properly placed in the room. (x=y=z).
2.) You will need to buy or create bass traps.
3.) You will a sound wave reflection absorption panel.
4.) Rearrange your room in such a way it reflects the studio design above.

Do more research on how to create bass traps and absorption panel by yourself without necessarily buying the expensive ones. You can do this by carefully examining the acoustic property of the material (carpet for example can be used as good bass traps).

For beginners in home recording and mixing, it is of primary importance and priority that you acoustically treat your room for flattest frequency response. Flattest frequency response tells the truth, nothing more nothing less. So it means that what you really hear during mixing can translate “accurately” to a wide variety of audio reproduction systems (like iPod, CD discman, television, radio, or even hi-fidelity systems with subwoofers or not).

If the room is not acoustically treated to handle “frequency” biases, your mix might only sound good in your studio but sounds awful when reproduced in other audio monitoring systems. No matter how expensive your nearfield monitor, you still need to acoustically treat your room.

If you are successful on this, it means that what you really hear can “accurately” translate to other audio systems. So if you mix it great, it will surely sound good in other audio systems. This is how important to have a mixing studio well acoustically treated.

What are the causes of this “frequency” biases problem that makes your mix lie to you (sound good in your studio but sounds bad in other studios or audio monitoring/speaker systems)?

Consider the arrangement below (which is not correct and not optimal placement for mixing records at home):

Problems of this setup:

1.) Standing waves and reflected waves, distort the real level of the frequency being heard by the engineer.

Why? When you see the arrows in the above screen, these arrows are the sound waves leaving the speaker, they reflect on the walls without acoustic treatment. What happen is that , they reflect right away because the speaker sound waves needs only to travel in a shorter distance as shown in the above screenshot.

These reflective waves can magnify or distort the real sound level of the mixed audio. So for example if that frequencies belongs to a guitar track around 500 to 5000Hz, the engineer may think the guitar volume is too loud, so what will happen is that he will lower the volume of that track in the mix, which in reality is not really loud but is composed of the standing/reflected waves from the monitoring system.

2. The studio monitors are not oriented well to the engineer, so he cannot visualize clearly the stereo image of the mix. Based on the screenshot, a lot of sound waves did not hit the engineers ear and instead reflect on the surfaces/walls of the studio. This again , can bias the reproduced sound.

Since mixing engineers depends on the reproduced sound to make judgment, erroneously reproduced sound (due to poor room acoustics) can produced an erroneous mix.

3.The worst is the placement of subwoofer. Since it is placed near the room corners, it will reflect those bass frequencies too early which again amplifies the bass image which in reality is a low level bass signal.

Solution:For the solution, please read this tutorial: Home Studio Recording and Mixing Studio Setup Acoustic Design.

If you are confused, ok this is an explanation in bulleted format:

1.) CD Audio standard is using 16 bits 44.1 KHz.
2.) Typically for better quality of recorded audio, it needs a high dynamic range for your music to flow.
3.) This high dynamic range can be obtained at a much higher bit rate (higher than 16 bits) which is 24 bit or 32 bits.
4.) Think of dynamic range as a size of your painting canvass. If a painting canvass size is limited; of course the resolution is limited also and you cannot clearly see the visual image of the painting at a farther distance.
5.) With big dynamic range available in higher recording bit rates, it is analogous to a large canvass painting which you can clearly see even the small details. This increased in resolution increases the ambiance, clarity and volume potential of the recorded audio. In music production, this is also offers a comfortable audio working environment since lots of audio details are available. This is recommended in mixing and mastering, where detailed tweaks to the audio signal are done.

OK, so you now understand the need to record at a much higher bit rate. So what is the standard? It all depends on the following:

1.) Sound card – you need to ensure that your sound card is capable of recording at a much higher than CD bit rate. For example, the industry standard has been 24 bits.

Quality inexpensive sound card can do this job, for example Audiophile 2496, which can record at 24 bits, 96 KHz:

Of course, it is not possible to get this kind of recording bit rates using onboard sound card or other types of sound cards not designed for professional music production.

2.) Recording software – Pro tools for example is capable of processing 24 bit audio. Adobe Audition is using 32 bit float, but is essentially a 24 bit audio processing engine internally. You need to make sure that your recording software can record at a much higher resolution than CD audio, to take advantage of increased audio resolution.

So how you are going to record 24 or 32 bits? If you are using Adobe Audition 1.5 (similar procedure can be found using other digital audio workstation), you can configure it as follows:

Step1: Install a high end sound card capable of recording high resolution audio.
Step2: Launched Adobe Audition.
Step3: Go to multi-track view tab.
Step4: Go to “Options” – “Settings” – Multitrack
Step5: Make sure that the “Track Record” is set to 32 bit
Step6. It is important also to mix down to 32 or 24 bit, so make sure that mix down is set to 32 bit audio.

Actually, for best audio quality that you can get from your music production, you need to ensure that:
1.) You are recording either 24bit or 32 bit.
2.) Mixdown to 24 bit or 32 bit.
3.) Mastering at 24 bit or 32 bit.

Finally once your work has been completed, you can then dither 24bit or 32bit audio wav to 16 bit CD audio in preparation for your CD audio replication/duplication process. This is done in the mastering stage of your music production.

In the audio mixing process, the mix down is mostly 24 bit audio or 32 bit which is higher than CD audio resolution (16 bit). If these are converted to 16 bit, there will losses in the audio digital signals due to downgrading the audio resolution.

These losses can be noticed in a 16 bit audio as minor distortion of the signal. Bear in mind that since dithering is adding “white noise”, this strategy is more preferable than not applying dithering at all which results to “distortion” (or we can say that white noise is more preferable than distortion).

By applying “noise shaping” techniques you can further minimize the effects of “white noise” on the converted audio. Noise shaping will basically place “white noise” away from audible frequencies (those that can be heard easily by humans). This will be covered also in this guide (see below).

Below are the some of the important steps in how to dither 24 bit or 32 bit audio to 16 bit CD audio. This is an important task in the audio mastering process. The steps illustrated below are using Adobe Audition 1.5, although similar procedures and functionalities can be done in mostly audio recording and mixing software.

Step1. Open the high bit depth audio in Adobe Audition Editor view.

Step2. Confirm the audio resolution by going into View — Wave properties. The audio is shown as:

It shows that the source file is a 44.1 KHz, 32 bit audio wav file.

Step3. Close the file in Adobe Audition Editor view.

Step4. Go to File — Batch processing – Click “Add Files” — navigate to the audio file location in your hard drive and click “Add”

Step5. Skip “Run script” but click “Resample” tab.

Step6. Make sure “Conversion settings” has been checked.

Step7. Click “Change destination format”.

Step8. Configure the following in the “Convert Sample type” menu.

Sample rate=44100
Channels = stereo
Resolution = 16
Pre/post filter = checked

Step9. Check “Enable Dithering”.
Step10. Dithering settings:

Dither depth = 0.5
p.d.f = Triangular
Noise shaping = 44.1 KHz

Screenshot:

Click OK.
Step11. Under “Output format” select WAV file and 16 bit (44.1Khz).
Step12. Select where you would like to save your converted audio file.