All about guitar - how to play the guitar, practicing the guitar, guitar effects pedals, acoustic guitar, electric guitar, and so much more. No matter what style of guitar you're into you'll find something here.
Monday, August 29, 2011
Riffs, Harmonics And Whammy Bars, Oh My!
In today's post, I'm taking a look into the "cool" of the guitar. Don't get me wrong, everything about the guitar is awesome, but today I'm focusing on all those cool tricks lead guitarists use to help make their playing stand out. The great thing is these are all things every guitar player can use in their own playing as well. I'll go in depth with some great riffs and how they are built, a few effects pedals that are out of this world, using the whammy bar, and even tips on finger tapping rhythms that are sure to impress. All the great guitar lessons are here at Mike's Guitar Talk.
Guitar solo at live concert
To play like the best, you'll have to practice like the best. I found a great introduction from Dream Theater's guitarist John Petrucci on practicing to be a rock star. Find it here at http://www.guitarworld.com/john-petrucci-practice-tips-part-2.
In order to become a well-rounded musician, you have to master the three major aspects of guitar playing: the technical side, the musical side and the creative side. The technical side comprises the actual physical components you need to have under your belt in order to get around your instrument, such as right- and left-hand technique, synchronization of both hands, executing scales, arpeggios and patterns, string-skipping, sweep picking, difficult licks, and memorizing (and playing) complete songs.
Once you've developed some technical facility on the guitar, the musical side (which entails theory, harmony, chord structure, ear training, sight-reading, composition and being able to hear chord progressions and licks) comes into play a lot more. This aspect is a lifelong study, but it's what makes you a good musician, as opposed to a good guitarist.
The creative side entails expressing yourself as an artist by composing music, lyrics or songs. It's often accessed in a totally opposite manner than the other two components-through free association. Sometimes just allowing yourself to noodle without any structure will enable you to stumble upon great new ideas, culminating in creating your own distinct voice on the instrument. I spent a lot of time developing my chops when I was younger. In doing so, I found that one of the hardest things was dealing with what to practice. That's not surprising, considering the almost inexhaustible supply of study materials (such as CDs, transcription books, magazines and instructional videos) available. With such a wealth of information out there, it's often intimidating to know where to begin, especially if you only have a limited amount of time.
I had to figure out how to organize my materials in such a way that I would be able to cover all three facets of guitar playing during a practice session. So I did the only thing I could think of: I set up a filing system. And you know what? It helped me so much, I still use it to this day! I heartily recommend that you create one for yourself.
Here's what I did (and you're welcome to use whatever suggestions work best for you): I created three different sections in my file cabinet, one for each of the aforementioned components of guitar playing. Subsequently, I divided each section into sub-categories. I bought a bunch of folders, and labeled each one with a particular sub-category.
Then, whenever I came across a piece of music that I wanted to learn, I'd assign it to a sub-category and pop it into its respective folder. The music could be from any source-a guitar lesson, a transcription, a magazine column, my own written exercises-it didn't matter. Everything went into that folder, including any books on that particular topic.
For example, let's take a look at how I filed the technical section. First, I made a list of all the technical sub-categories I could think of, and then I assigned a folder to each one. I created one folder for scales (which also included scale patterns and sequences), and another one for arpeggios. Then I had a folder on left-hand studies, where I included things such as legato licks a la Allan Holdsworth and trilling exercises. I also made a folder that contained intervallic studies, such as string-skipping licks, and one containing chop-building exercises, such as speed studies and chromatic lines.
I also created a separate folder that only contained licks, whether written, transcribed, or culled from magazines. For example, I used to transcribe licks from Steve Morse and Al DiMeola, and they actually worked like technical exercises. The mere effort required to master those licks helped my technique immensely. By the way, you may have noticed that I didn't make a folder for right-hand exercises-that's because the exercises in all the folders automatically encompass the right hand.
Of course, you're not limited to just those sub-category choices. Create ones that interest you. When I was younger, I had a folder on right-hand tapping, but since I don't really use this technique that often anymore, I no longer require a tapping folder. But if you want to master your tapping technique, by all means create a folder. Same thing goes for whammy bar tricks, etc.
I break down my musical component section into the following sub-categories: sight-reading (which includes single-string reading studies from Berklee College of Music [the school I attended] and classical pieces), chords and chord theory (which contains chord books, articles that depict chord boxes, and chord-melody transcriptions), and general music theory.
If you want to master a lot of different musical styles, I strongly suggest that you also create a styles folder. In this folder, you'd have blues, country and jazz sub-categories for starters, as well as any other styles you're interested in (death metal, bluegrass, etc.).The creative section will contain folders where you can catalogue your songs, chord progressions, melodies and lyrics-any original work that defines you as a guitarist and an artist.
The cool thing with this filing system is that when you go to practice, you not only have tons of material to choose from, but you can customize your practice sessions. This is especially helpful to guitarists who are in a practice rut where they don't know what to work on, or where to start, so they practice the same things over and over.
For example, let's say you have two hours a day to practice, and you've decided you're going to dedicate every Monday, Wednesday and Friday to working on scales and arpeggios. With this filing system, you'll never have to play the same exercises every day.
Just go into the appropriate folder, and, if you filed your topics correctly, you'll have a bunch of different things to work that concentrate on the same technique. That way, you'll never get bored and you'll always be working on something new and interesting.
This entry comes from Dimebag Darrell's classic Guitar World column, "Riffer Madness" To me and my band, guitar riffs are what it's all about. We know that every time we jam on a great riff we've got a fighting chance of writing a great song! You don't have to go to G.l.T. or know a bunch of weird-assed chords and scales to come up with killer shit. But you've got to be totally into what you're doing! Check out Judas Priest's British Steel album if you don't believe me. It's packed full of god-like riffs, and most of them aren't hard to play. If you don't already own this album, buy it-it's essential shit, man! Anyway, here's a couple of ideas that might help you make the most of a good, heavy riff. One of our audience's favorite riffs is the main one in our encore, "Cowboys From Hell" (Cowboys From Hell, Atco). It's a pretty easy riff to play 'cause it's made of the first rock scale we all learn-the E minor blues scale (Figures la and lb.) The first time you hear this riff is in the song's intro where I play it an octave higher than I do during the rest of the track.(Figure 2.)
Hearing it played an octave higher is like an appetizer-it introduces you to the riff and makes you hungry for more! Playing it higher first also makes the full-blown unsion (Figure 3) sound real heavy when it kicks in. I guess you could say that FIGURE 2 is the "body blow" and FIGURE 3 is the "knockout punch."
My bud Jerry Cantrell from Alice In Chains does the same sort of thing on "Would?" He starts off by playing the verse riff high up the neck, then slams you in the teeth when the vocals enter by playing it an octave lower. To give the main "Cowboys" riff (Figure 3) even more balls, I play power chords on the E and A notes instead of just playing single notes like I do in the intro version (Figure 2). 1 also add some low-end chunk by applying some heavy-duty palm muting. My whammy system is set up so I can yank the bar up as well as do dive-bombs with it. This means that if I accidentally push down on the bridge with my palm, my strings go sharp and sound out of tune. I make sure this never happens by never resting my hand on the bridge when muting. I always do my muting just in front of the bridge. I also use the idea of repeating a riff in different octaves during the bridge of "Cowboys" (Figure 4a). There's a short, one-bar descending run I play twice halfway through the bridge (bar 4). At the end (bar 8)(Figure 4b), I play the same run an octave higher. This definitely makes the bridge sound cooler than if I just played the run in the same register twice.
GET A GRIP When I play live, I jump around like an idiot for an hour-and-a-half or more under a lighting rig that's hotter than hell. This makes me sweat like a pig, and makes it real tough for me to keep a firm grip on my picks, even those that are supposed to be non-slip. Losing control of your pick on stage sucks, so I scratch some deep X's into both sides of my pick with something sharp, like a dart. Doing this makes your picks look like shit-but at least you won't look like an asshole because you dropped one in the middle of a solo!
An essential part of the electric guitar is the whammy bar. I thought it would be good to get into some lessons about how to use the whammy bar effectively, but first I found a good video that features phrasing on the whammy bar here at http://www.guitarmasterclass.net/ls/whammy_bar_phrasing/.
Today we will focus on my favorite subject - phrasing
I'll try to show how phrase using whammy bar.
Floyd Rose type tremolo is a very delicate instrument and we should use it with care.
It something like a playing violin or trombone, when you have only your ears to control the intonation.
I wrote a simple song which contains several whammy tricks: vibrato, dives, releases.
So, feel like Steve Vai and make your whammy sing! :)
I usd mostly A majorscale and F#minorpentatonic scale.
We are going to use:
-whammy licks: vibrato, dives, releases
-slides,
This is the preset I used for the POD XT live for this lesson:
Amp: MS 2003 Deity Lead Drive 7 - Bass 3 - Middle8 - Treble 7 - Presence 5
This month we're gonna talk about harmonics-how to get 'em, where you can find 'em and what you can do with 'em. There are a number of different ways you can make harmonics happen. You can induce 'em with your pick (pinch harmonics), you can tap 'em like Eddie Van Halen does sometimes (tap or touch harmonics) or you can get 'em by lightly resting one of your left-hand fingers on a string and then picking it. The last type are called natural harmonics, and they're the suckers we're gonna be dicking with.
How
The easiest place to get a natural harmonic on any string is at the 12th fret. All you do is lightly rest one of your lefthand fingers on a string directly above that fret and then pick it. Don't let the string touch the fret, though, or it won't work, dad! When you do this right you'll hear a bell-like note that's exactly one octave higher than the open-string note. To help make harmonics easier to get, use your lead (bridge) pickup and a lot of gain. When I first started experimenting with harmonics, I'd sometimes hook up two distortion boxes just to get my strings "frying," which helped bring out the harmonics. Also, once you've chimed the harmonic, it's not necessary to leave your finger on the string-in fact, if you let go of the string immediately after you pick it the harmonic will ring twice as well.
Where
You can also get harmonics happening above other frets like the 7th, 5th and 4th. Some dudes seem to think that these are the only points where harmonics happen but, as far as I'm concerned, there is literally a harmonic to be found at any place on any string. Check this out and you'll hear what I'm saying: rest your left-hand bird (middle) finger lightly over the highest fret of your fat E string. Then start chugging out a groove on that string with your pick. While you're doing that, keep your left-hand finger resting lightly on the string and start moving it slowly towards the nut. You should hear a shit-load of different harmonics all over the string!
Some of my favorite harmonics are located between frets. There are two really cool ones between the 2nd and 3rd frets that I use a lot. One is at about a quarter of the way between the 2nd and 3rd frets and the other is at about three quarters of the way. They're pretty hard to get, so once you find 'em make a mental note of exactly where they are.
I use some pretty radical harmonics at the beginning of "Heresy" [Cowboys From Hell.] FIGURE 1 shows a riff similar to the one I'm talking about and, as you can see, it uses harmonics on the low E string.
The best way to make sure you're playing this right is to listen to the record real carefully and then find the exact spots where all the harmonics are. Use your ears and your eyes, man--look and listen!
To Bar or Not To Bar
A lot of guitarists tend to only use harmonics when they want to make weird noises with their whammy bars. That's cool but, as FIGURE 1 shows, you don't need a tremolo arm to make harmonics wail. Two of my favorite players, Edward Van Halen and Randy Rhoads, did some real happening things with harmonics without reaching for their bars! FIGURE 2 is similar to the verse riff of "Mouth For War" [Vulgar Display Of Power].
In bar 4 I play a simple little fill using harmonics a quarter of the way between the 2nd and 3rd frets on the G and B strings to create a high-pitched percussive sound that gives the riff an extra dimension. And, once again, no whammy shit is going on.
Harmonics are cool to screw around with, so don't be afraid to experiment with 'em. As long as you remember to look and listen you'll do just fine.
What's shakin', tough guy? Like I promised at the end of last month's column, this time I'm gonna light you up on how to do "harmonic squeals," like the ones at the end of "Cemetery Gates" (Cowboys From Hell.) A bunch of you have written in asking about this technique.
To get "harmonic screams" (same shit, different term) happening, you need a whammy bar. So, if your axe doesn't have one, then you're gonna have to sit this lesson out-sorry, dude! Also, just so you know, we're gonna be doing some pretty brutal dives that will definitely knock a non-locking tremolo system way out of tune. So a locking one, like a Floyd Rose-type, is kind of essential.
In case you're not exactly sure what I mean by a harmonic scream, there's a real long, slow one in "This Love" (Vulgar Display Of Power) which starts at 6:21 (CD time) and runs to the very end of the track. You can also hear me doing a bunch of them in "Cemetery Gates, " between 6:14 and the end, where I imitate Phil's [Anselmo, Pantera's vocalist] screams. I love that sort of vocal stuff, but there's no way in hell I can do it with my voice-I don't have that kinda range! So, harmonic screams are my way of "singing out, " using my guitar instead of my throat. That's why I really dig this technique.
I stumbled on harmonic squeals when I was dicking around one day. A lot of people think I use a harmonizer or a [Digitech] Whammy Pedal to do them, but I don't; all I use is my bar and some natural harmonics. To make harmonics scream, I first dump my Floyd Rose real quick, hit a harmonic with my left hand while the string is still flapping, and then use the bar to pull it up to the pitch I wanna hit.
If this sounds kinda complex to you, don't schiz; it's actually a pretty simple thing to do once you've got the technique down. So, let's learn how to do a real basic harmonic scream in "slow motion," by breaking the idea down into four easy steps. Let's use the harmonic that's directly above the 5th fret on the G string ('cos it's a pretty easy one to nail) and make it "scream" up to its original pitch of G. First though, dial up a distorted sound (remember, gain helps harmonics happen) and switch to your lead (bridge) pickup.
Step 1: Position your left hand so you're ready to hit the 5th-fret harmonic on the G string with your bird (middle) finger. Then mute the high E and B strings with your left-hand index finger, and the low E, A and D with your thumb by wrapping it around the top of the neck.
Step 2: Flick the G string with your bird finger and dump the bar down to the pitch you want the scream to start out at. You can take the bar down as little or as far as you want; just don't take it down too far, or the string will die of shock and the harmonic won't happen.
Step 3: As soon as the bar is dumped, sound the harmonic by lightly tapping the G string directly above the 5th fret with your bird finger. While you're doing this, make sure you're still keeping the other strings quiet with your thumb and index finger.
Step 4: As soon as you've hit the harmonic, release pressure on the bar and let the G string return back up to pitch. As long as you've sounded the harmonic properly, it'll "scream" up to G (as shown in FIGURE 1).
The first few times you do this you're gonna hear the open G string "growl" before the scream starts happening. This is just because you're doing everything in slow motion. Once you've got this technique down, though, you won't hear the growl because you'll be doing the first three steps so quickly they'll almost be simultaneous. If it takes you some time to get these squeals happening, don't skid-it took me a while too.
Work on this technique until you can nail FIGURE 1 no problem, then move onto FIGURE 2.
This one stays on the G string but has you "screaming" a bunch of different harmonics up to pitch. The last one can be a bitch to hit, but stick with it 'cos it sounds real cool when you nail it. Once you get this one down, try doing the same thing on the other five strings.
What's up Dad, we're back! Last time we got into using the whammy bar to make natural harmonics scream back up to pitch. In this column we're gonna be using the bar to to pull these jewels up to notes that are higher than their regular pitch. One example is screaming the harmonic at the 4th fret (regular pitch is B) on the G string all the way up to D (Figure 1).
For you to be able to able to do this your bridge needs to be floating so you can yank the bar up as well as push it down. It's up to you to decide how you set your bridges up, but just so you know, I have my Floyd set up so that I'm able to pull a note on the G string up about two-and-and-half steps.
Basically, the technique you need to get these high-pitched bitch-bastards screaming is exactly the same as the one we talked about last month: flick the string with your left hand, dump the bar down, lightly tap the harmonic you want and then let the whammy come back up real smoothly--so the harmonic squeals. The only difference is that this time out you've gotta pull up on your bar, so that the harmonic goes past its regular pitch and up to the note you want the "scream" to end on. To do this you've gotta use your ears as well as your hands--your hands do the work and your ears tell 'em how far to go.
Backwards or forwards? The choice is yours!
To pull a harmonic up to an exact higher pitch requires some pretty close control of the bar. I've found that with the bar pointing towards the back of my guitar--towards the end strap button--I can more accurately get the note I'm aiming for, because I have to push down on the bar to get there--think about it! But whenever I'm aiming for a gut-wrenching squeal, I go for it with the bar facing the front. There's a different feel to both ways, so experiement to find which one works best for you. Backwards or forwards? The choice is yours.
Anyway, enough rapping about whammy bars and shit; let's get into some jamming. To get cooking on this new idea, check out FIGURE 2.
This has you screaming the harmonic at the fifth fret of the G string up to four different notes: G (return to pitch); A (up a whole step); B (up two steps) and C (up two-and-a-half steps). I've got you hitting a power chord before each scream, so you can hear the pitch you're aiming for just before you go for it with the harmonic. Use your ears and pay atention to the pitch. Once you've got FIGURE 2 down, try FIGURE 3, whichi s the same exact deal except without the power chords to help you out. This time you're flying blind!
Once you can nail FIGURE 3 every time, you're ready to start cuttin' up. Try squealing every harmonic you can find on every string, and never be afraid to experiment; that's how most of us come up with some of our coolest shit. The great thing about this technique is you can use it to make your guitar sing a melody or just squeal wildly outta control--it's up to you.
To finish up, I'm gonna leave you with a challenge, FIGURE 4.
This is the first melodic squeal at the end of Cemetery Gates (Cowboys From Hell), where I follow Philip's vocal melody. Here I scream the harmonic at the 4th fret on the G string up to E, which is two-and-a-half steps above its resting pitch of B. Then, after holding it there for a measure, I drop it smoothly down to C, which is half a step above its resting pitch. Thje touch thing about FIGURE 4 is that you never get to use the harmonic's resting pitch (B) as a reference point--you're either above or below it, but never on it.
These new pedals – Corona Chorus, Flashback Delay & Looper, Vortex Flanger, Shaker Vibrato and Hall of Fame Reverb – deliver first-class tones right out of the box and feature a true bypass and analog-dry-through design that guarantees maximum tonal integrity and ultimate clarity. A small footprint, easy battery access and super high-grade components complete these awesome pedals. In short, they combine simplicity and flexibility with unrivalled sound quality – they simply take cool to a whole new level!
TC Electronic believes in moving the possibilities of guitar forward and all these new pedals feature an amazing new concept called ‘TonePrint’ that gives users instant access to the sounds of their favorite guitar heroes. A TonePrint isn’t just a static preset, it’s a complete re-tuning of the pedal including the sound and how the pots react – everything that makes a pedal unique.
TC Electronic has collaborated with some of the best guitarists in the world – such as John Petrucci, Ron ‘Bumblefoot’ Thal, Joe Perry, Orianthi and Doug Aldrich – to create the first batch of TonePrints, but that’s just the beginning. The list of contributing artists will expand massively in the future, so forget emulation, let’s talk collaboration!
A simple USB cable connects these pedals to any PC or Mac for the actual Tone Transfusion. Each pedal is capable of holding one TonePrint at a time, but the concept is unlimited as users can swap TonePrints as many times as they want. All of these custom made TonePrints can be downloaded at TC Electronic’s website, and best of all – it’s easy, fast and totally free!
Shaker Vibrato
Time to shake things up with this awesome vibrato! This beauty features two types of vibrato: a classic true pitch vibrato and ‘latch mode’ where the effect is only active when you press and hold the switch. This allows for subtle vibrato and faux-whammy bar effects without having to tap dance all night. To top if off, intuitive Speed, Depth, Color and Ramp controls let the users make their own ‘shakes’ on the fly.
Vortex Flanger
This flanger goes from classic flanger sounds to a 747 taking off! Speed, Depth, Feedback and Delay-Time controls offer a creative and expansive palette of tonal options. Vortex Flanger is built with guitarists in mind, so it features a toggle switch to go between classic pedal flanger tones and 60’s tape-flange effects.
Corona Chorus
Corona Chorus is the go-to pedal for that shimmering and warbly goodness. With two different chorus settings – the classic, world-renowned TC Electronic SCF pedal and a Tri-Chorus – as well as a custom TonePrint setting, Corona Chorus handles any situation or musical style with flying colors. Also, stereo inputs and outputs ensure super flexible set-up possibilities, and Speed, Depth, Color and Level controls allow for instant tweaking.
Flashback Delay & Looper
Flashback Delay & Looper features 7 seconds of delay time and every delay type one could ever wish for – from TC Electronic’s legendary 2290 delay to old-school tape echo. In total, there are 9 different types to choose from, and it even doubles as a looper!
Flashback Delay & Looper also features TC Electronic’s audio tapping technology, allowing users to set the delay times by strumming the guitar, and a toggle switch that goes between quarter notes, dotted 8s or stereo with different values left and right. Hall of Fame Reverb
Hall of Fame Reverb is a collection of the ultimate reverbs, packed tightly in one cool pedal that handles any situation that calls for a touch (or handfuls) of rich reverberation. In total, Hall of Fame Reverb offers 10 reverb types for a world of inspiration! Halls, Plates, Rooms, Chambers, etc. will cover anything from subtle ambience to full-blown cathedral greatness, and Decay, Color and Level controls allows for easy and instant tweaking of the sounds. Further, stereo inputs and outputs, handling both instrument and line level/FX Loop signals, ensure super flexible routing options.
Guitar finger tapping
Now let's close up shop with one of the most popular solo choices for guitar players all over the world: finger tapping. This is an exercise that will help you tap in time and make sure all the notes fall into place with the rest of the song. Check it out at http://www.gibson.com/en-us/Lifestyle/Features/blues-on-tap-0804-2011/.
For a while there, two-handed tapping had quite the stigma about it. Although players like Frank Zappa, Jimi Hendrix, ZZ Top’s Billy Gibbons and Genesis’ Steve Hackett had all experimented with prototypical forms of tapping in the ’60s and ’70s, Eddie Van Halen really developed the style into a phenomenon, starting with “Eruption” in 1978. And then the imitators came. Once guitarists figured out what Eddie was doing, tapping became another flash trick, like pinch harmonics and whammy bar wiggling, that could be used to sound cool when you couldn’t think of anything else to do.
By the time the ’90s hit, tapping was virtually illegal. Overuse had sapped the technique of its originality. Now, of course, tapping is once again accepted as a valid style, and players are taking it in interesting new directions – one of which has its roots in Stanley Jordan and ’80s players such as T.J. Helmerich (who has a knack of continuing to get better and better, too, by the way). It has continued to grow in the hands of players like Megadeth’s Chris Broderick. This style involves playing basslines or chords with one hand while executing a melody or harmony with the other, and although it can be a little daunting at first, after a little bit of work it can start to feel more natural. Although it's great as a flashy rock or metal technique, a cleaner tone is required so you can hear each note clearly. It’s especially suited to blues and jazz styles – and there’s a world of indie experimentation out there just waiting for an enterprising guitarist to explore.
For the best results and playability, you’ll need a guitar with relatively low action. Some light compression may help you even out dynamic variations while your hands get up to speed, too – after all, even if you regularly employ Van Halen-style tapping, the fingers of your fretting hand may not be used to carrying an entire melody on the fretboard.
Let’s look at a blues example in the G Minor Pentatonic scale. First, use your “regular” fretting hand to hammer the following pattern. Try to flatten out your fretting hand fingers against the fretboard just enough that they mute any unneeded notes, but not so hard that they sound phantom notes themselves. And note the simple G5 power chord at the end.
Next, we’re going to add a simple melody in the well-known pentatonic box shape, tapping the tips of the fingers on the fretting hand. Use whichever fingers are comfortable for you – it’s great if you can use all four digits, but if only your index and middle fingers are strong enough for now, use those to get the melody into your head (while still practicing to build up the others). Note the slight quarter-step bend on the second last note. This will add a little bit of sass to the lick while setting up a nice resolution to that G note on the 17th fret of the D string at the very end.
Now it’s time to put it all together.
Finally, we’re going to add a little swing to the whole shebang. Offset each melody note with a laid-back shuffle groove (think Stevie Ray Vaughan’s “Pride and Joy”). As you become more comfortable with the technique you’ll be able to add more articulation – more slides, more bends, vibrato, etc.
There are a million ways to employ this style, but I find that this kind of rhythmic/pattern-based method is the best for getting your fingers used to the whole idea. From there, you can incorporate chords, more sophisticated walking basslines and some really out-there counterpoint parts.
So there you have it. Hopefully these tips will launch your lead guitar playing to a new level. There is a lot of information out there and some of the best places to look are your favorite guitar legends. You found it here at Mike's Guitar Talk.
One of our audience's favorite riffs is the main one in our encore, "Cowboys From Hell" (Cowboys From Hell, Atco). It's a pretty easy riff to play 'cause it's made of the first rock scale we all learn-the E minor blues scale (Figures la and lb.) The first time you hear this riff is in the song's intro where I play it an octave higher than I do during the rest of the track.(Figure 2.)
No comments:
Post a Comment