Wednesday, December 28, 2005

Power handling pt.2

In this post I shall explain a bit of physics behind part 1.

Impedance Matching:
As a general rule, the maximum power transfer from an active device like an amplifier to an external device like a speaker occurs when the impedance of the external device matches that of the source. That optimum power is 50% of the total power when the impedance of the amplifier is matched to that of the speaker. Improper impedance matching can lead to excessive power use, distortion, and noise problems.









Matching amplifier to cab:
The maximum power transfer from an active device like an amplifier to an external device like a speaker occurs when the impedance of the external device matches that of the source. That optimum power is 50% of the total power when the impedance of the amplifier is matched to that of the speaker. For example, assume that the maximum distortion-free voltage from the amplifier is 40 volts:







Note that it is safer in terms of total power to go to higher impedance speakers (series speakers), but more typical practice is to put speakers in parallel, lowering the impedance.

Speaker Output Power:












Matching Microphone to Input:
The maximum power transfer from an active device like a microphone to an amplifier occurs when the impedance of amplifier input matches that of the source device. That optimum power is 50% of the total power when the impedances match. If a high impedance microphone (50,000 ohms) is connected directly to a low impedance input (600 ohms), it will deliver only about 5% of the power you get if impedance matched (13 dB less signal). In addition, it is more subject to external interference such as 60 Hz hum. If a low impedance microphone (600 ohms) is connected directly to a high impedance input (50000 ohms), it will likewise deliver only about 5% of the power you would get when impedance matched (a 13 dB loss).







Move Loudspeaker Closer to Listener:
One of the obvious ways to get more amplified sound to the listener is to move the loudspeaker closer to the listener. The amount of anticipated improvement in the potential acoustic gain can be modeled for the simplified amplification system. As a practical matter in larger auditoriums, this means using additional speakers which are closer to the listener to add to the sound from a main speaker cluster. A problem which arises is that the signal from the amplifier to the distant speaker travels at the speed of light whereas the direct sound from the source travels at the speed of sound. A sound image problem results from the fact that the sound from the nearby speaker reaches the listener before the sound from the visible source in the front of the auditorium - your ear locates a sound partly by time of arrival and therefore hears it coming from the speaker. The location conflict between your ears and eyes can be disconcerting. This is typically overcome by using a digital delay for the sound signal going to the distant speakers.

More sound engineering information can be found here

Power handling pt.1

In an attempt to help a fellow musician I wrote an article to discuss the major practical issues regarding amplifiers, cabs and power handling. First I'll tell you what were the answers to his questions:

So what does it mean when they say 'This amplifier is rated 200W at 4ohms'?
This means that the maximum power that the amplifier delivers is 200W and this happens at a load of 4ohms

What happens if you use a larger cab like 8ohms?
Trying to keep you away from the mathematics, in a nutshell, the amp will deliver less power and will also drive less the amp (so you're always safe not to blow the amp)


What happens if you use a smaller cab like 2ohms?
More current will flow, which will eventually drive the head even harder and will eventually blow the head. Note that the amp will still deliver LESS power. Yes dudes...don't think that by driving the amp harder you're getting more power :) You'll actually getting more REQUIRED POWER resulting in heat. The delivered power is always less...

To boil everything down:

1) You blow a cab if you use an amp rated more than the maximum power that the cab can handle
2) You blow a head if your total cab impedance is less than the impedance that the head can handle.
3) You get full amp power if you use the recommended impedance (impedance matching)

Now you can ask also questions like 'what's the difference between using two 8 ohm cab in parallel (which make a 4ohm total) and using 1 4ohm cab. This is now more of sound engineering which is a very nice subject. Ideally the bigger the speakers surface area the better, so you deliver bigger volumes of air which produces better sound...

In my next post I'll discuss the physics behind it.

Bass Head Slave

Intended for bassists and guitarists. Many of us are happy with their amplifiers, especially on stage (stage sound). To deliver more power they invest in a PA. Now there are two types of approaches:

1) That musician who shares the PA with the rest of the band (through a mixing console)
2) That musician who has his own power amplifier to deliver more power from his instrument

For the first scenario, the musician can connect to the power amp using an XLR cable (yes similar to the microphone cable) from his amplifier's D.I. to the mixing console.

For the second scenario, more importantly, the musician has to use the amplifier's Line Out (aka Slave Out in some amps), and not the D.I. This is because the D.I. produces a weak signal which needs some sort of pre-amplification (ex. through a mixing console) prior to feed it to a power amp. The power amp normally has a high impedance...

Wednesday, December 21, 2005

It’s a fiddle!

MUSIC shop boss Steve Kowalski has been told he will have to pay to play if his customers want to try out his instruments before they buy.

And that, he says, is a fiddle.

The Performing Rights Society claims he needs a licence if he, or any of his punters, want to "have a go" on anything from a harmonica to a harpsichord or castanets to clarinets.

And officers have told him that if he doesn’t stump up cash to the tune of £114 he will have to face the music.

But Steve, 53, who is gob-smacked by the order, said: "They can go whistle!"

He says he wants the threat removing – no strings attached!

Talking from his shop, the well-established Jones Music on Charlotte Street in Macclesfield, he asked: "Has anyone used their common sense here?"

Steve, who took over the 78-year-old established business a year ago, received a call out of the blue from PRS who asked if he or his customers tried out musical instruments.

He said: "I thought, what a daft question, of course we do."

When he said they did, they told him that if anyone played a riff – an identifiable piece of music – he was in breach of copyright and was breaking the law.

"They said it constituted a public performance!" he gasped. "I thought someone was winding me up.

"I have never heard anything so ridiculous in my life. It means that customers will either have to try something out without the piece sounding melodious or they will have to buy it untried.

"I am certainly not going to pay for a licence. I am making a stand for all musical instrument shops who are just going about their business."

When Steve, who lives in Macclesfield with partner Sally, asked PRS what they were going to do about it, they told him they would send in their copyright protection squad.

"I could tell that meant trouble," he said.

Steve, who himself plays lead guitar in a band, ironically called "Rough Trade", said the cost of the licence was determined by the size of the shop and since Jones Music was 1,500 square feet he would be in for a £114 bill.

"It’s not the money," he said. "It is the principal. I don’t intend to rock over this one."

Keith Gilbert, PRS Performance Sales Director said: "Royalties are crucial – they keep songwriters and musicians writing more music. And royalties are paid by everyone that plays music in public.

"Music shops pay like everyone else, but get a 30 per cent discount if their only music use is for demonstration purposes."


Macclesfield Express

Exhaust Diameter


I've been told that a big exhaust outlet will decrease the power since it is a naturally aspirated engine. Not only power, but also throttle and low-end torque.



This morning I installed a flange at the back of the exhaust to decrease the diameter of the outlet to around 2". I will benchmark my Mazda later on this week.

Monday, December 19, 2005

Bugatti Veyron


When you push a car past 180mph, the world starts to get awfully fizzy and a little bit frightening. When you go past 200mph it actually becomes blurred. Almost like you’re trapped in an early Queen pop video. At this sort of speed the tyres and the suspension are reacting to events that happened some time ago, and they have not finished reacting before they’re being asked to do something else. The result is a terrifying vibration that rattles your optical nerves, causing double vision. This is not good when you’re covering 300ft a second.

Happily, stopping distances become irrelevant because you won’t see the obstacle in the first place. By the time you know it was there, you’ll have gone through the windscreen, through the Pearly Gates and be half way across God’s breakfast table.

It has always been thus. When Louis Rigolly broke the 100mph barrier in his Gobron in 1904, the vibration would have been terrifying. And I dare say that driving an E-type at 150mph in 1966 must have been a bit sporty as well.

But once you go past 200mph it isn’t just the suspension and the tyres you have to worry about. The biggest problem is the air. At 100mph it’s relaxed. At 150mph it’s a breeze. But at 200mph it has sufficient power to lift an 800,000lb jumbo jet off the ground. A 200mph gust of wind is strong enough to knock down an entire city. So getting a car to behave itself in conditions like these is tough.

Of course, at £810,000, it is also jolly expensive, but when you look at the history of its development you’ll discover it’s rather more than just a car...

IFramed!

Thanks to my buddy I found out that the gallery had a few problems with some browsers. Problem originated from the use of iframes which by now are depreceated...I replaced it with the OBJECT tags and now works like a breeze.

Blogging tools

I found this forum which displays an updated list of useful blogging tools and add-ons. At the moment I'm really interested in putting some sort of calendar on my blog.

Image power

Kenneth's Online Repository: Why you can never look as hot as cover girls

Bah, humbug!

Kenneth's Online Repository: Bah, humbug!
Some thoughts for christmas...

Sunday, December 18, 2005

Search for sound


My bass guitar, the famous Musicman Stingray, should growl all the time. Just keep it hungry. Feed it small portions of raw meat mixed with gunpowder...In a quest to achieve that classic Musicman Stingray growl, I've spent the early morning experimenting with the sound (waking up neighbours and rattling the earth in the process). I'll explain you my methodology:

I connect the stingray to a Boss GEB7 and the latter to a Behringer rig. I flat both the Stingray and the Behringer. This way I don't need to bother to ever tamper with knobs, even if I'm playing on a different rig...However I color the sound through the Boss GEB7 as follows:

50Hz: +10dB
120Hz: +10dB
400Hz: +2.5dB
500Hz/800Hz/4.5KHz/10Khz: 0dB
Level: 0

With this configuration I get a good punch and a nice growl and I normally leave it like that. If I want to scare the crowd and make their beer rattle inside their belly (followed by a visit to the toilet to throw up) I boost a bit the bass and mids on my Stingray. That's why I also believe the mid-knob is the "scare-your-audience"-knob along with the bassknob :)

Note that this way I don't overdrive the amp, although I get that aggressive growl and solid punch which is a characteristic of Stingray. Even when you boost the bass and mids from the Stingray, make sure you don't overdrive anything. If you want more volume, crank the amp not the pre-amp (Boss/Stingray). Then if i want to slap in the middle of the song, I just tap the Boss pedal with my foot to de-activate the pre-amplification process!

By the way, my gear is as follows (the equipment in italics is for backup purposes only):

Bass guitars:
- Stingray | Translucent Red | Maple Fretboard | 1996 model (bought 26/8/05) [Serial number: 48086]
- Tanglewood P-Bass (hotrodded)
- Tanglewood 6 string bass

Rig:
- Behringer BX3000T head
- Behringer BA210 2x10" cab
- Behringer BA115 1x15" cab
- Behringer BT108 combo
- Laney RBW200(R2) combo

Pedals:
- Boss GEB7
- Zoom 506
- Behringer V-Amp

Simple, huh?

Thursday, December 15, 2005

Vodafone/6680 Settings

These are all the settings I use on my Nokia 6680 with the Vodafone network:

In the Tools/Settings/Connection/Access Points menu, I have the following entries:

1) Internet
Data bearer - Packet Data
Access point name - internet
username - internet
prompt password - no
password - internet
authentication - normal
homepage - http://www.vodafone.com.mt

2) MMS GPRS
Data bearer - Packet Data
Access point name - mms.vodafone.com.mt
username - none
prompot password - no
password - n/a
authentication - normal
homepage - http://mms.vodafone.com.mt

3) WAP GPRS
Data bearer - Packet Data
Access point name - wap.vodafone.com.mt
username - none
prompt password - no
password - n/a
authentication - normal
homepage - http://wap.vodafone.com.mt

4) Vodafone live!
Data bearer - Packet Data
Access point name - wap.vodafone.com.mt
username - none
prompt password - no
password - n/a
authentication - normal
homepage - http://live.vodafone.com.mt

The SMS centre number is +356941816

Agile Messenger

I've just installed Agile Messenger on my Nokia 6680. Try it guys!! You can connect to MSN, ICQ, Yahoo, AOL, or Google Talk in no time... It is very reliable and the traffic is optimized so that your GPRS bill will not be sky high :)

Wednesday, December 14, 2005

Bass Tuition

My bass buddy, Chalee, has agreed to give me some badass bass lessons next summer. Woohoo! Finally someone who can assess my bassiness and help me become a better bassist. In the meantime, I'll shred more basslines on my own...

As an insight, Chalee is the bassist for local bands Zizza Ensemble and Fire. He's into Jazz and is one of the best Maltese bassists I currently know of. Other local bassists who enjoy my respect (in no particular order) are: Rex (Corkskrew, Lithomancy), Antonio Ghio (Fakawi), Jon (Hiddensun), and Edward (Precedance).

Sideskirt dilemma


I am contemplating whether to fit the Mazda sideskirt shown in the photo or not. In actual fact this photo was edited by my brother. In the original one, the car had a front splitter and a rear bumper extension. But since I'm not bodykit fan, I only want the sideskirts...Reason being that I want to make the car look more sportish and it will also cover a pinch I have on the running board :p

The thing is that I'm afraid whether it will look a bit funny with just the sideskirts - I am expecting some opinions about this from other forums...

Tuesday, December 13, 2005

Minor sequences

The first post about music theory! In this lesson I'd like to touch upon Sequences.

A sequence is simply a number of notes. It can be 2,3,4 or more. Let's approach this topic with a touch of music theory.

The A natural minor scale is comprised of 8 notes from A to A having no sharps nor flats.

A-B-C-D-E-F-G-A

If we wanted to play the A minor scale using a sequence of 3 notes, we would proceed as follows. Starting on the root note A, we would play the first 3 notes in the scale (A-B-C). Next, we would play 3 notes beginning on the second note (B-C-D), followed by the third (C-D-E) and so on. See how simple this concept is?

Using sequences in your playing can liven up your bass fills and runs, create more tension in your solos, even make practicing scales sound musical. Adding subtle nuances to your playing can make a HUGE difference in your playing style.

Saturday, December 10, 2005

Gallery

I've added a flash gallery on the right side bar. I'm quite sure you'll find it amusing :)

Resolution

It may be too early to state the list, for the ignorant. My plan is to list it, and whoever cares, adds or subtracts to my list. So here they come - the 20 things I'd like to change about myself over the next year:

1. Eat better. Less snacking on junk food, hell, some days my junkfood snack is my only meal of the day.
2. Spend more time with my bubbles (aka my girlfriend)
3. Do all the Oracle courses.
4. I'd like to be more sociable in every occasion.
5. Care more about how I look.
6. Less speeding on the freeways, more enjoying the drive.
7. Cut my nails on time and not be lazy about it.
8. Be more spontaneous.
9. Be more open about things.
10. Smile more.
11. Sigh less.
12. Learn how to prioritize things, funny that this is #12.
13. Watch more independent films.
14. Not buy useless junk.
15. Replace my 6 year old pair of shoes with a new pair without going back to the old ones.
16. Be a bargain hunter.
17. Be more respectful to others.
18. Be more sensitive.
19. Be more verbal about things. Speak my mind.
20. Profit.

Please don't bug me not to spend $$$ in my car, cos you know I won't.

Shazaam!

I recently came up with a theory. Something I'd like to call JTDR (Jamie's Theory of Dream Reality), it goes something like this:

It is a fact that all human beings in this world dream, some animals are also capable of dreaming but as of right now let's focus on the homosapiens, the smart bipeds, us! Haven't you ever wondered before just how complex dreams can be? For example let's say that in your dream you were given a present and this present was wrapped such that you don't know what is inside. You look around at all the suspiciously giddy smiles of your friends that are waiting for you to unwrap this gift. You unwrap the gift only to find a snake which within the next 0.5 seconds had lunged at you and bit you on your face much to the delight of all your friends. Unfortunate, something that would only happen in a dream. Normal. But let's talk about that dream some more...

In the dream you were presented a gift in which you do not know the contents of. Your friends apparently knew and you were pleasantly surprised when out of the box comes 2 poisoned fangs that jumped straight for your eye. But how is this even all possible when your brain is the one dreaming it? Your brain is the author of this very story called your dream and yet it was able to surprise you. How is the brain capable of knowing something that you don't and keep it a secret from you? It's able to replicate what you experience in your waking state, surely you also wouldn't know what was in the box if it really was your birthday and you were really given a wrapped present. Things like this happen all the time in dreams! Ever bought anything and asked for the price in your dream? How did you not already know the price? Ever been surprised in a dream (surprised as in someone just jumped out of a dark corner and scared you shitless)? How did you not know that was going to happen? It seems as if your dreams are as unpredictable as your waking life.

We all have our daily routines, we work, study, and laugh. The normal everyday things that when put together constructs our journey of life. But what if our journey of life in our waking state is nothing more than a dream, a recreation of the mind? What if the "real" journey goes on when we sleep, when we do things that would never be possible when we are not asleep? To be frank, I'm not particularly religious and although I've been raised in a Christian household there are many things that are part of Christianity that I cannot conform to. But naturally I feel that there is something greater out there, a god, chi, a pool of consciousness that every living thing is connected to. What if when we dream we experience a connection to this "pool"? What if the journeys we take in our dream IS what makes our life? What if when we die we finally start living our life? Something that we've only tasted by dreaming.

It boggles me mind, I seriously have been thinking about this for the past couple of days.

Life, 1 Pt, .9 FL OZ at a time

and slowly drowning.

Here I am, sitting and staring at the bottle of Fontanella water next to me. "Mountain Spring Water" it says, I doubt that... the water probably came from some rarely cleaned purification system in the south of Malta. Who cares. On the label it says that I can get 5c for the empty bottle if I'm living in Rome. God I wish I live in Rome... or Switzerland, or in some remote area of Canada, maybe even Egypt. I'm tired of this, the commute, the people, the mundane activities, the friends that are not really friends... so tired. Unfortunately, no matter how much I want to get away, it's just not practical at the moment.

You don't reap what you sow, sorry.

It's not a submarine!

After yesterdays rain, and therefore, since we are in Malta, heavily flooded roads, my Mazda has suffered from some floods as well...A wet alternator belt making whistling noise, a flooded running board, and a broken H3 bulb.



No need to mention, this morning I woke up early to fix the things. As for the wet alternator belt, I just left it dry and made a 30 minute drive. For the running board, I found out that there's a plastic tap which can be removed and clogged water can then be drained out, and as regards the bulb, well, just a simple 95cents replacement with another one.

I am still planning to replace the H3 bulbs anyways, with Philips or Osram enhanced lights (similar to Xenon lights but without the ballast kit). I'll post something in the next days about this.

As for next time, I will not think that my car is the Mach 5 supercar capable of submerging under water :)

Friday, December 09, 2005

The old days!

Surfing through one of my favourite exits, Activebass.com, I bumped on my fellow Elliot Gomez who runs a website featuring all the activebass members. And he reminded me how different i looked a couple of years ago - it was the time when i dedicated more time to music than to university days, the time where i prefered holding the bass guitar rather than a girl...ok...maybe i'm exagerrating a bit to keep the post interesting *cough*

Thursday, December 08, 2005

Snip snipz

Hi, cutting your own hair is hard. Support your local barber/hair stylist and always take advantage of their professional service. Thank you.

BMAs 2005 results

Just arrived from the BMA event. The crowd was quite large - there wasn't space to move around. I was irritated by the fact that the event didn't begin until two hours after the doors were open; considering the scenario where you are standing for two hours, glaring at an empty stage, and pushed continuously by the moving crowd, ladies and gents, I can assure you that they weren't the most pleasant two hours one can spend.

However at 23:30, Jonathan Abel, Bay Radio's young but prominent presenter, announced the beginning of the event. The lights were quite acceptable, but the sound was a total crap for the first 30 minutes. Around midnight, the first band kicked in. It was the Corkskrew, featuring their popular catchy song 'Cool Sunday'. The other bands which played, in no particular order, were:

- Muttley
- Ira Losco
- Filletti and Friends
- Tenishia
- Scar
- Winter Moods
- Dripht
- Bitterside
- Lara

The awards were given as follows: the best band was awarded to Corkskrew, the best solo artist was awarded to Ivan Filletti, and the best ever song award was given to Winter Moods with their song 'Everyday Song'. There were a couple of other awards which I forgot at the moment. Whilst every musician and band tried to impress the audience either by the way they moved (take into consideration Lara who seemed more to participate in a pole dance rather than at a music event), the way they dressed, etc, there was only one band which was really itself, and which, in my opinion, kicked ass - Dripht, the ska/raggae band which is actually quite amusing and makes good quality music.

The highlight of the evening was just exactly when I was returning home - a group of guys greeted me with 'Hey, isn't that guy, the Musicman dude?'. It's always nice to have new fans you've never seen before who have remembered you even weeks after a small gig. If one of you out there is seeing this, I'm James (I apologize I didn't present myself this night), but you can still call me the Musicman dude if you prefer.

Wednesday, December 07, 2005

As promised...

... here's a pic of my car freshly taken this morning at the garage.


For those interested in the specs:
Make: Mazda
Model: Lantis
Year: 1997
Engine: 1.5 litre, 16V DOHC
Transmission: Manual 5 Speed
Number of cylinders: 4
Number of valves per cylinder: 4
Driven wheels: Front wheel drive
Horse Power: 90
Top Speed: 110mph (177km/h)
0-60mph/0-100km/h: 11.9s

BMAs 2005

I guess that today i must dedicate it solely to music. As soon as I finish tweaking the blog i'll pick up the laptop from work, study on some songs for tomorrow's rehearsals and resume my self-taught 'bass-improvisation' exercises which I'll talk about in later posts. In the evening I'll pop up to Eden's arena to watch out the much 'expected-by-local-musicians', the Bay Music Awards. I'll keep you updated about the winners of the awards.

Blog Maintanance

It's 3 AM and i'm here working on this blog. Actually i had stupiditly lost the whole template and spent the last two hours getting it back. On the way of reconstructing the blog i've discovered some flaws which i smoothed out. One of the major flaws is that when a post is created, the other users won't notice it if the page is cached in their browsers. So i wrote a nifty little javascript to automatically refresh the page.

6680 is back

The mobile was successfully repaired. It turned out that the problem was from the MMC door switch. The switch was always open-circuit thus making the mobile believe that the user is going to plug out the memory card...duh...

Tuesday, December 06, 2005

Calculate your mileage online!

Do you want to know how much money you're spending on fuel? Then visit the online mileage calculator. I got the following results:

Miles Per Gallon: 31.58
Kilometers Per Litre: 11.13
Litres Per 100 Kilometers: 8.98
Cost Per Mile: Lm 0.06
Cost Per Kilometer: Lm 0.04

Can you go lower than me? :)

Sunday, December 04, 2005

I think I screwed it up

Why do I always have to mess things up? It must be something running in the blood i guess. I remember my dad screwing up my toys when i was a kid... Well this time it was me who screwed up my toy, the beloved Nokia 6680. In an attempt to remove the express-on cover with a screwdriver, I think I moved the chassis and made some lose contact in its internal circuitry. Basically it stopped seeing the Memory Card. When I put some pressure with my fingers at the back of the mobile, sometime the card is detected again, but after a while it gives me again the error "Please removed memory card and press ok". I tried all possible scenarios for this to workaround it, but in vain. Well, tomorrow I'll take it to my nearest mobile repair shop and see if I wasted $$$ down the drain. Fingers crossed.

Friday, December 02, 2005

Free apps for your Nokia

I always wanted an MSN client for my mobile. Thanks God that I found this cool website. It offers free Java based applications for mobile devices, in my case, for Nokia 6680. There are a lot of apps for other phones. Visit it! I'll try to grab as much software as I can...

More apps at: http://my-symbian.com/main/index3.php?cat=3
More ringtones/wallpapers at: http://phone.mobile9.com/nokia/6680/

Using Gmail on Nokia 6680


Right now my Nokia 6680 is retrieving emails from my Gmail account... I can also send emails through the gmail account. This is simply fantastic. I'll give you some tips of how I managed to do that. From the Gmail point of view, you need to enable POP. Now here's the trick - If you're like me and have thousands of emails already, in order not to swamp the mobile with emails, be sure to enable POP for newly arrived messages... The Gmail engineers were brilliant enough to think about that feature...

From the Nokia's side, yo need to create a new mailbox from the messaging menu. These are the settings which you need to set:

- Access Point in use: Internet
- Outgoing mail server: smtp.gmail.com
- Send Message: Immediately
- Username: [username]@gmail.com
- Incoming mail server: pop.gmail.com
- Mail Box Type: POP3
- Security (Ports): On (993/995)
- APOP secure login: Off
- Retrieve Headers Only

Now I can be fully dependant on my Nokia 6680 :) Trying to sell my old PDA to a work colleague in the meantime...