Tuesday, April 29, 2008

Part V: Tracking Tips


When it comes to the actual recording of tracks let me try to suggest a few things to keep in mind. The first is understanding your gain structure. As signal travels form one piece of gear to the next and through the interconnections, your quality is only as strong as the weakest link. This is usually the cables, but lets me explain all stages.

If you are recording an instrument like guitar, bass, etc, your gain starts with that instrument. I went over some of the pointers for making sure your instruments are good in the previous installment. Your guitar or bass is sending what is called an ‘instrument level’ signal. This is a high impedance, low voltage signal. Remember impedance is just a word that describes resistance. Higher impedance is more resistance and therefore more strain on the current capacities of the equipment. But an instrument level signal is very fragile. Its also unbalanced meaning it has no third wire ground in it. So you will want to keep instrument cords short and high quality. Also you will want to keep your instruments and their cables away from electromagnetic interference coming from computer monitors and hard drives. You can step back from monitors or turn them off to eliminate this buzzing. Listen for it with volume knobs up. Microphone signals are also low. But they travel inside a balanced XLR cable and you can run pretty long lengths of this cable safely. Again, just keep cables new and in good condition. Treat your cables nicely! Don’t step on them or drop the metal ends on the hard floor.

If you have acquired a decent amount of gear, even inexpensive gear, and are looking for an upgrade, you can do very, very well by re-wiring your studio with high quality cables and keeping them organized. You’ll want to run power cords with each other, signal wires with each other, digital interconnects with each other and computer cables with each other. If you have to cross one cable over another, do it at a 90 degree angle so it only touches the other at one small point and does not run with it for a great length. If you do this and use good quality cables (Not Hosa brand, hehe), you will notice that your noise floor will go way down. You will be able to turn up the volume on your monitors and hear just low level, non buzzing hiss. Also, you should use a decent power conditioner like a Monster Cable two rack space unit or similar. You can get one of these conditioners for a few hundred bucks. A home theatre one will have different outlets with different kinds of filtering on it.

Ok, back to gain staging. Your low level signal, whether its instrument level or mic level, will travel along a high quality cable and into a mic preamplifier or direct box which is a preamplifier. Here the level goes up to +4 line level. Notice it was at instrument level or mic level, not it’s at line level. There are two standards for this level. -10 unbalanced and +4 balanced. Even if you are using unbalanced connections here and there, you want to work at +4 line level when you set your equipment up. You will see switches on your gear that will let you choose this option. Now if course if you are getting too high a level somewhere and you need to switch down to get the gain correct, do it. But in general, you want the extra gain that you get with a +4 level. By the way they call -10 consumer level and +4 pro level. Balanced connections which are three prong or three conductor are +4 and two conductor cords like guitar cords and RCA phono plugs are considered -10. A three conductor stereo ¼ inch plug can be either but usually is a used for s +4 level. The important thing to remember is that you want the highest level signal before clipping that you can. Adjust your preamp’s gain so that you get a good level out from there and you do not hear any crackling or distortion.

After a low level signal is jumped up to line level by a preamplifier it is ready to go into the computer interface box. The interface box might actually also have a preamp in it and maybe you are doing that if you don’t have a good outboard preamp. The main thing these boxes contain besides preamps is Analog to Digital and Digital to Analog converters. Your preamp signal is an analog signal. The computer needs a digital one. So these converters are in this box. Or maybe you have an outboard AD/DA converter box but if you have this, you probably know enough not to be reading my blog…. :)

When we are talking about digital recording, you want to get the highest level you can, but you never want to go above zero in the computer program or clip the A/D converter on the way in. You actually could afford to push the A/D a bit but usually it’s calibrated so that a clip on the A/D equals an ‘over’ on the computer. ‘Overs’ are digital levels above the calibrated zero level. In a computer program, the red light is always an indicator of a zero level and you don’t ever want to see any of those, ever. You can hit at .01 db below, but don’t go over.

Because you will not be able to fully anticipate the dynamics of the performance, you want to check to see what the loudest level you think you might get is, and then set your gain stages to let you hit 3-4 db below zero. Because digital is so clean, you can even afford to go lower but really just making sure you are a few db below absolute zero is fine. If you do hit zero by accident and you don’t hear a clipping sound on playback, never mind it and then keep an eye on things.

Alright, assuming you have set your preamp levels well and you have recorded a clean track into the computer, move on. I will explain more about this in mixing later but just remember that your gain stages in your computer mixer are additive so the more tracks you have, the more volume you will create down at the master fader. I usually start a 24 track mix with all channel faders at -13.and the master fader at zero. A 36 channel mix might have all faders at -16. But this depends on how loud you record your track into the computer. If you keep an eye on levels, you will never need to move your master fader below or above zero.

On now, never normalize or apply any kind of processing to any of your raw tracks. You will only degrade them and make it harder to keep quality high and gain structures in order. Normalizing only brings the level up to the highest possible level and this means you get no extra quality but that you will be feeding these higher levels into all your channels and plug ins. You will then have to turn them down and every time you make an adjustment in a digital mixer, it has to make mathematical calculations that potentially can degrade your sound. In the perfect situation, you would mix everything at such a level so that you would never have to turn down the master fader, never have to turn down a plug-in fader and only have to adjust the channel faders. Most experienced engineers can achieve this and this is what you want to go for.

Ok I think that is about it for gain staging. Now, let me talk about things to keep in mind as far as the logistics of tracking goes. There are mono and stereo tracks. A stereo track would be needed for a keyboard or a sound sample file. All other tracks you will be using in your computer workstation will be mono files. (Except stereo FX channels but tracks are your recorded files and channels are what they are played though.) Even cymbals will be two mono files. One panned hard left and one panned hard right. Recording a mono track into a stereo file is a waste of storage space and limits your flexibility and your plug-in power as well.

You want to name your files perfectly. Name all your channels and your aux sends or busses. Also name all the tracks you mix down and anytime you name something do it with forethought. You will be doing a lot of cleaning up of files down the line and you really want to be able to remember what is what when you do that. Let me give you some examples:

“Rhythm Guitar L 2 Neve” This is the second rhythm guitar track that was recorded through a Neve preamp.

“Mike Vox OD 3” This would be the singer’s 3rd vocal track that is not the main track but an additional “Overdub” take.

Another example might be bass parts that have been recorded as three separate tracks. “Bass DI”, “Bass Comp”, and “Bass 421” This would be one track for the bass that was just recorded direct with a direct box. “Bass comp” was sent through a ‘channel strip” outboard box that had a preamp and compressor in it and you turned on the compressor on this track. “Bass 421” was the track that came from the bass player’s amp and speaker cabinet that had a Sennheiser MD-421 microphone pointed directly at the center of the cone. With this kind of track naming, you will remember exactly what you did to each track. Just naming them “Bass 1”, “Bass 2” and “Bass 3” tells you nothing and you might get lost in the mixing process. Or if you or another engineer ever has to work on this session, they will need really well named tracks because they were not there to remember anything about how things were recorded. Keeping a track sheet and notes is also a very good idea.

Also when you make mix-down files of your mixes, you will want to name them in the same descriptive way. You can keep them in folders that are also named descriptively like “Cannibal Test Mixes” and in there you would put files like “Bloodthirst test mix 1” and then later “Bloodthirst test mix 2 vox up 1 db” Keeping track of names and folders this way is extremely important.

This also applies to your outboard gear. Get yourself some white ‘board’ tape or use blue painter’s tape and tape and mark everything. You can mark knob positions, mic positions, write names on things, etc. Tape and mark everything. Speaking of tape, you will want to tape down cords to the floor so people don’t trip on them and tape mic cords to the drummer’s drum cage, and things like this.

Now, let me talk about doing takes. If you are using Pro Tools, you have an option of making takes that overlay in a fresh window and then going back through them all. With other programs, you will want to punch in over older takes and just leave the takes lying on each other. Or make new well names channels for these takes. You always want to walk the line between pushing yourself or whoever the performer is to get the best take but not go so far as to burn the person out. If you cannot get something, go back later and get it. A fresh head will often cure any problems like this. You can usually try a few times and if it needs more work go back later or stop and practice it more. The studio is really stressful and it’s always good to be patient and also optimistic and open with options.

oh, if you are wondering what that rag is doing on the nut of the guitar in the pic above, thats a trick for limiting open string noise when tracking solos or certain rhythm parts, try it. Slide it over the nut more to get more dampening.

I’ll add to this installment as I think of more things….

Cheers,

Colin

Sunday, April 27, 2008

Part IV: Recording Preparations

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When we talk about recording preparations, what we are talking about is aspects that will affect your final product in a way that you can never take back. These little nuances all have a cumulative effect. They all add up and if you miss a few of them, you are looking at major, unsolvable problems. And since it’s not very expensive to take care of these little issues, it’s in your best interest to address them. I’ll discuss each instrumentalist and their preparations individually.

Guitar players: A lot of people have forgotten how important the guitar is to their tone. But yes, the quality of your guitar matters. Not just the pickups, but the actual woods and construction. Generally, a two hundred dollar guitar will not deliver a resonant tone. But assuming that you have a quality instrument, just make sure it is set up properly. If you are using two guitars or have two guitar players, take all the instruments you will use to the luthier and get them set up. It’s better to have slightly higher action than lower and it’s really necessary that the intonation be perfect. All the guitars you use should be set up by the same guy at the same time. It’s true that you can do this yourself, but I suggest that you don’t try. It’s just too important and the cost is usually minimal. You need a strobe tuner anyway and most people don’t have one of those.

In metal, a lot of people use EMG pickups. The 81 is bright and has a lot of gain and the 85 or 89 is a little darker and more mellow. Both offer a pre-compressed and high voltage output. EMG’s have the capability of making a mediocre amp sound decent because they supply a lot of the tone before the amp has to do anything to it. The problem is that they make all amps sound too similar. Also they are not very responsive to the player’s dynamics and they are not very good for clean tone. You can’t turn down the guitar volume knob to clean up the gain. But that aside, they do offer a good sound for metal and can be very good if they are in a good guitar and used with a good amp.

Passive pickups are a bit more versatile and responsive and they will give you a less scratchy sound than EMG’s. But the problem is that many of them do not have enough gain for metal. With the new high gain tube amps that are out, this is less of a problem though. I can highly recommend the Dimarzio Evolution for a high output passive pickup that delivers gain, tone and versatility. You can experiment with others such as the Dimarzio PAF Pro, Duncan Custom or other designs..

Make sure that your wiring is clean and buzz free. It’s too common that a guitar or bass has a ground buzz problem. If you have your amp turned on and set to the distortion channel and do not hear a buzz with any cord plugged in, then your power is clean. But if you add your guitar and cord to the mix and hear a buzz when the volume is up and you are not playing, you need to check it out. It’s the cord or the guitar. Get that fixed before you record.

When you record, you can get about 4 hours of playing time on a pack of strings. Replace them before they lose their snap. When you put a new set of strings on, tap the low strings with your finger so they hit the frets and listen to how they sound when they bounce back. They are very bright and metallic. Now play on them for about 10 minutes and tap on them again. This is when they sound best. After this little break in period, they are ready. When you notice that this sound is going away, replace them. It’s usually only several hours at most of playing time. You can buy strings in bulk and they will only cost about 6 dollars a pack at the most. If you are tracking left and right sides and you can do one or both performances on one pack, then your cost per song will be either 6 or 12 dollars. Multiply that by 10 songs and you have 60 to 120 dollars for your entire album. If it cost you 120 dollars to get two guitars intonated at the shop, you’re up to 240 dollars. This is not expensive! That’s less than the cost of one day at a recording studio for your entire album to be perfect.

Also make sure you get new cords, many new batteries for any pedals you use, many new picks and make sure you have a good tuner. You will be checking your tuning every five minutes or less. I’ll talk more about these things in the columns about recording guitars later.

If you have a tube guitar amplifier and the tubes are old, replace them. At the least, replace the preamp tubes which will only cost you about 60 dollars. I also recommend that if you are getting a new amp, you not do it a week before you record. It can take a long time to understand a new amp and you will need that time. Regardless, you definitely should record a ‘reamp’ track when you record so this will let you go back and fix your tone later if you mess up. You can watch my guitar tone video to find out what this is and how it works. But its basically a direct track that you record in addition to the mic’d signals that you can send back into an amp later to re-record your tine. You’ll need a good direct box and a $200 Reamp box to do this.

Bass players have a similar situation. But if your bass has been set up and intonated anytime in the recent past and you have not changed your tuning, you may not need to take it to the shop. Bass strings will last for about a song or ‘maybe’ two if you are very fast. Again, check for grounding problems and get cords, batteries, etc. By the way, try to use the shortest cords you can when recording bass and guitar

Drummers have a lot to worry about. Drums are really hard to maintain, tune and keep in tune. If you are a drummer and you have not dedicated yourself to learning how to tune your instrument, I’d really recommend that you start doing that. It can take some time, but you will be able to learn. If you are a recording guy and you don’t want to trust drummers anymore, well then you can learn yourself. I recommend a video by Bob Gatzen for learning this art. You can also search Youtube for excerpts.

Before you record drums, make sure all the hardware is working and nothing is rattling or falling apart. Check out your rims and see if they are true. They are cheap and at least you should replace the bad ones. When you have the rims off, check the bearing edges for dents. Run some fine sandpaper over rough bearing edges. Replace bent lugs and any other cheap hardware you can. Try to make sure the tuning lugs turn smoothly. This way you can be sure the heads will stay in tune.

If you have not replaced your bottom heads in more than a year, it’s a must do. If you have, and you are on a budget you can skip it and just tune them. If you have the extra money, it’s well worth it. Bottom heads that are one ply and clear are usually best for rock, metal, etc. The top heads can be one or two ply, clear or coated. Coated heads have a duller attack that is good for jazz and some rock. Clear heads have a nice ‘tick’ sound as the stick meets the head. A one ply head will be very resonant and can be good for making older thick shelled drums sound better. A thick two ply head like Remo Pinstripes might have too much of a plastic thud sound and I generally stay away from those. I personally recommend the Evans G2 clear. It’s a two ply head but each ply is thin and it is a great compromise between resonance and durability.

You can tune drums where the bottom head is a half step higher than the top or where they are about equal. Also each drum has 2 or three tuning ranges. The first is the lowest where the heads first start to ring. And there is always at least one higher one and usually this is the one to use if you are playing fast. If the band is slower and tunes down, you might like the lowest range. Again, you definitely will need to study drum tuning before you do this or get someone who can tune. Another cool way to learn and speed things up is to use a tension watch. Check it out.

Also, another thing the band and drummer can do is to find out if a click track can be made. You can make one in the computer and then make a practice CD for the drummer to play to. It would be a guitar track or two and a click sound. The drummer can practice to this for a month or two before tracking. If you do this, the drummer can track all his parts to a click in the studio and this will not only tighten up the performance, it will allow you to cut and paste sections of the recording.


Vocalists usually just kick back until it’s their turn but they should definitely be staying healthy, getting exercise and going over their parts in their spare time. Also, it’s pretty helpful to type out all your lyrics. Make a print-out for yourself and another one for the engineer so he can follow along with you and refer to the words when you guys are recording.

Recording engineers need to ask themselves if they are truly ready to record the entire album at home or if they should use a pro studio for certain aspects. It can be worth it to use a studio for drums, mixing and mastering and just track guitars, bass and vocals at home. And when you are at the pro studio, you can watch the engineer like a hawk and learn a lot. But if you do this, it’s best to learn from a guy who has at least 10 years experiences or more and knows all the proper ways to record and mix. Many new engineers never learned the basics and this is why they have never advanced past a certain stage. Good luck and have fun!

Friday, April 4, 2008

Part III: The Gear


Note: The reason I am posting this article installment is that it is a needed bridge to get to the other more complex concepts and techniques that I want to discuss with home recordists. For many, this article deals with basics that you have already dealt with. And for others, it deals with aspects they have not yet dealt with. I can’t make a really comprehensive article about the various kinds of gear in a home studio and their functions. That requires a book. Glean what you can from this article and in the near future I will take you off into more complex techniques. Sorry if this article is of little use to many of you!

It is now possible to get very good sonic accuracy from relatively low cost equipment. There is a level of quality you do not want to go below, but other than that, it’s possible to get very good results from a fairly low cost home studio.

As I have said before, your monitors and your room are more important than anything else in your studio. But assuming you have those two issues settled, its time now to move on to the fun stuff. First you will need a computer.

The platform choice is basically between Mac and PC. My advice is that a home studio owner use the PC platform. The reason for this is cost. MAC computers are very solid and stable, but it could cost you twice as much money to get your studio running and to keep it running.

A PC may give you more problems with the fine details of installing drivers, keeping the peripherals running, etc, but this is often worth it for the home studio owner because of the lower cost and higher availability of those parts. If you do have the extra money, are familiar with the MAC platform already and want to go that route, you will do well.

Ok, if you are running a MAC you will use OS X, if you are running a PC you will use Windows XP Professional Edition. You should not use the Vista operating system unless you want to experiment a bit. If you buy a new computer that has Vista installed, you can buy a copy of XP and install that instead. Vista is very new and is not as reliable as XP for audio yet. Those running Windows XP can use this guide to optimize their settings for audio use:
http://www.digitalproducer.com/2002/11_nov/features/11_04/optimize_pcaudio.htm

The way you build a home studio is based on what you want to accomplish. I recommend that musicians use the home studio to augment time at a pro studio. Also using it for writing purposes is very handy. During this time, you can build your experience and eventually, you can get good enough to record your album at home.

The most effective way to go is to record drums at a pro studio, then record the other tracks at home and go back to the pro studio to mix and then send out for mastering. In later installations, I will probably talk about recording drums for those that want to go in this direction, but honestly, recording drums is pretty serious and those people are going to need an education much greater than these blog posts.

A very good alternative to recording drums is to use the Toontrack family of drum programs. Check out EZ Drummer or Superior Drummer 2.0 at www.toontrack.com You can get a drum sound that is nearly as good as real drums with this method.

Supposing that you have either recorded drums at another studio or have sampled drums like those from EZ Drummer, you will need to now record guitars, bass and vocals. This means that you will only have to have 2 channels of mix preamps. The more types and brands you have, the more colors you are painting with, but even just having two really good preamps is very good for the home musician. I recommend the Vintech Dual 72 for the semi pro users. It’s a Neve style dual preamp that you can use for anything. It will be super high quality and never let you down. It costs about 1200 dollars for two channels. If you need a cheaper alternative, just remember that you get what you pay for. 600 dollars per channel of preamp and higher is where real quality comes in. But you can get quite adequate quality for about 300-400 dollars per channel. There are many brands to choose from. Try www.fmraudio.com for a low cost solution. Or just keep these prices in mind and shop around. There are too many brands for me to cover them all here. Preamps that are built into audio interface cards are ok, but you should step up from this at buy a dedicated preamp or two. Buy a couple of preamps that will take an XLR or ¼ inch input that you can use as a direct input (DI). This way you can mic up cabinets or record vocals with vocal mics, or plug straight in for recording a DI track.

Another way to go is to buy a small mixing board. You will get many preamps and the ability to do more versatile operations. In the home studio range, I’d suggest you stick with Mackie or Allen and Heath. Cheaper than that and you will get low quality. Those two brands are quite good for the money.

Next is the audio interface card. This is where your analog source from the preamps or mixer get changed into digital and go into the computer. The actual conversion takes place in the A/D converter. This is the Analog to Digital converter. Many audio cards have these built into them. But a few are full digital cards and will require a separate AD converter. I recommend you get a card (interface) with built in A/D and D/A converters

If you are using a laptop, you will need a Firewire or USB 2.0 card. If you are using a desktop, you can go Firewire or USB or use a PCI card. Either way, there are a lot of options. PCI interfaces may be a more stable option though. For the higher end of home recording, I recommend RME. Under this I’d say MOTU, Digidesign and M-Audio. Also, you will have fewer problems running a desktop over a laptop, but a new and fast laptop with a good card can work for just recording a few tracks at a time. You can mix as many tracks as you need though. Again, you get what you pay for.

So far, you have your speakers, you room has been set up to work well, you have bought a couple preamps or a mixing console and an audio interface card. Now you need software. The most popular programs are Pro Tools, Cubase, Nuendo, and Sonar for PC and Pro Tools and Digital Performer for MAC.

Pro Tools needs a Digidesign approved audio card to run it, but the others will run on any audio card. Pro Tools is the industry standard and if you plan on going back and forth with another Pro Tools equipped studio, that’s your best bet. You can buy a book for Pro Tools on Amazon.com and learn it. It’s a bit of an odd program, but there are tons of people to help you. It is the most popular program.

Steinberg is the maker of both Cubase and Nuendo. Originally, Cubase was more geared towards home recordists and Nuendo was more pro, but now they are almost identical. Pick one and run with it. I use Nuendo myself and it’s a very intuitive and stable program. Sonar is made by Cakewalk and is also very good but it will not be quite as easy to get help with because it’s not as popular. I hear it works just as well as the others. I’m sure it does. Digital Performer is a very deep and high quality MIDI and audio program for MAC and most MAC users use it in combination with Pro Tools. You can buy instructional books for all of these programs and I would advise it.

I would also suggest that those individuals who want to get into home recording begin using the internet as a library and start visiting as many forums and websites as possible that pertain to recording. Don’t get caught up in gear lust, just try to glean as much information as you can. Getting into recording is like taking yourself to college and you will need to be constantly on the lookout for new techniques and pointers. Always ask questions and keep absorbing information like a vacuum cleaner.

You will undoubtedly run into many problems installing drivers, getting things to work properly, etc. For this reason, you should try to find an audio buddy. Find another person who has a few years experience in this that is near you to help you when you get stuck. If they are running a certain program such as one of those listed below, find out what they run, and you can run it too. This way you can compare notes. They can come over and help you when you are stuck or talk you through a problem on the phone. If all your friends are running Nuendo on PCs and you get Pro Tools and a MAC, you’ll be very sorry you did.

Ok, back to the gear. Most musicians who want to just record their ideas at home and start to learn the art of recording only will need speakers, computer, sound card, preamp and software. They can use sampled drums and record direct guitar or bass tone from a Line 6 POD or use a guitar simulator plug in. If you want to actually mic up a cabinet and record guitar tone the professional way, watch my video for instructions on doing that. If you want to record bass, the best way is to plug in directly from the bass into a preamp and from there into the audio interface.

If you want to record vocals at home you will need a good large diaphragm condenser mic. On the low end I would recommend the Oktava MC319 and on the semi pro end, I’d suggest the Neumann TLM 103. Actually, the Neuman is a fully professional mic. You can also try an AKG 414 BULS. Other good inexpensive mics are the Audio Technica 4033, 4055 and 4060. There are many Chinese made mics that are pretty good these days but none of them will be better then these I just listed and you are in hit or miss territory. There are also a lot of half Chinese, half American made mics and I’d just stuck with AKG, Neuman or Audio Technica if I were you.

You can record a singer with just a good preamp, good converters (probably built into your card in most cases), and that’s all. But usually, the best way to record vocals is to compress them with a good compressor before they go into the digital domain. The problem with this is that you now need another piece of gear that is often expensive, but you also now have to learn how to listen to compression. But you have to start somewhere. For a cheap compressor, I’d recommend the FMR Audio RNC compressor. And if you want to get better, you should spend about 800 dollars or more. With the RNC, you can set it on auto, let it peel off about 4 db of volume off the vocalist and just record that into the computer. Vocals are very dynamic. They always need to re-compressed with your plug in compressor in the computer during mixing, but it’s very beneficial to also have them pre compressed on the way in. But when you do this, you are locking the compression into the audio track and you can’t go backwards. But then again, it’s necessary for vocals if you want a pro sound. Here is a good reason to let a pro do your vocals for you if you are not sure if you can understand compression. I’d say, watch the professional do it and ask him questions, then try to mimic what he does. I’ll do an installation on compression in the future. It can take a few years to really get the hang of it. But if you are not trying to record your best album at home, you can always record without compression or with an RNC and just experiment. It’s best to get your hands dirty.

There are so many other aspects that I should try to put into this installment but really can’t. In fact this entire article is really too basic for those that are already building a studio and too complex for those that are just getting acquainted with the technology. I hope there is something that is in here that can help bridge a gap in your knowledge. For future articles, I will have to suppose that the reader has already done their homework on basic techniques. But let me just list a few key terms. If you don’t know what these are, find out, and take yourself to school on the basic concepts of recording. There are many books and I will try to make a list of them later. But you will need to know these terms if you are going to be even slightly successful with recording.

Signal to Noise Ratio
Dynamic Range
Bit Depth
Sample Rate
Analog to Digital Conversion
Digital to Analog Conversion
Sample Rate Conversion
Dither
DI Track
Reamp
Line Level voltage
+4 and -10 level voltage
Nyquist Frequency
Attack
Release
Threshold
ADAT Optical
XLR
AES/EBU
Instrument cable
Speaker cable
¼ inch mono and ¼ inch stereo jacks
Insert cable
Patch Bay
EM interference
Human hearing frequency response
Standing waves
Diffusion
Absorption

The list goes on and on…….

Are you sure you want to record your own album??