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Saturday, 16 August 2014

One year later...

As it turns out it is one year since I last wrote something on this blog. On year may not seem so long for some of you out there and I can totally understand that. Even when I was in school, one year would just fly by with only a few major happenings throughout the year. This past year though, has been something absolutely incredible.In this post I will do my best to sum up the year that has passed but I will also tell you a bit about my future. So, let's begin where we left it last time...

My last post was about the AKG K490NC headphones. I didn't buy them just because I wanted a new pair of headphones but because I had been accepted to the Global Active Programme, previously known as Learning School. I will not go to much in depth about what the actual programme was or what kind of work I did since it isn't really relevant for an audio blog. GAP meant that I would be travelling around the world for a year, and I couldn't bring my Denon headphones and my Koss Porta Pro aren't really suited for use in airplanes, buses and so on. So therefore I invested in a pair of noise-cancelling headphones.

My travels started in Scotland, where I visited Glasgow, Edinburgh, and Aberdeen along with two of the people I would be travelling for the year. We then continued up to the Shetland Islands where we were based at a high school doing various kinds of voluntary work. Then during autumn break we headed off to Italy for a short holiday. We visited Rome, Florence and Venice. After that we flew to Germany where we visited a high school in a small town, not much bigger than where I grew up. In the middle of our stay in Germany I got invited to go on a trip to Japan and of course I could not resist that so I spent almost two weeks over in Asia. I came back for one last week in Germany before heading home to my old school for a month before Christmas break.

I did a few audio-related things during this part of the trip, beginning with visiting the Mareel arts & cinema center in Shetland Islands. It's a modern top-quality music venue that also has cinemas, recording studios, and so on. We were given a guided tour by one of the employees and he showed us around the studio, the radio-room, the projector-rooms in the cinemas, and so on. It was a really fascinating place and a really valuable resource for the people living on the islands. During my stay in Shetland I was also lucky to see The Revellers live (a local folk rock band, they're good!).  In Italy it was much less informal. There I saw lots of street musicians and one night in Rome I ended up with some strangers rehearsing for a ukulele gig. A Swedish girl and an Italian guy playing ukulele and the singer was a Russian girl. Amazing people and amazing music led to a really good night. Germany, Japan and Sweden didn't include anything specific that I can think of.

The next part of the trip, the longer part, started on the 20th of January when I flew to America. Here we met up with a new member of the group. We had ten days of holidays before school started so we visited Philadelphia, Washington DC, and New York. It was very cold but nevertheless we had a good time. The school we visited in the US was about 45 minutes drive outside of New York and it was really interesting seeing bits of the American high school life with my own eyes. When our stay there was over we continued on towards New Zealand, with a one-day stopover in Los Angeles and two days in Fiji. In New Zealand we were in Christchurch most of the time working at an all boys high school and we also did a couple of trips to various places around the south island, including Fox Glacier. Our next stop was Canberra, the capitol of Australia. It wasn't quite what I had imagined Australia to be like but I still enjoyed it very much and the school we were at was really interesting. The last two weeks in Australia we had easter holidays so some of us spent part of the first week hiking in the Snowy Mountains and then for the remainder of the holidays we went to the south coast and then Sydney. Sydney was incredible, probably my favourite city on earth. There were great street musicians, we were even lucky enough to see Winterbourne, check them out!

As you probably know, the great Opera House is in Sydney. I had a brief look at the concerts that would be on during our stay in Sydney. There was one with Jeff Beck and another with Iron & Wine. I had no idea who either of them were, although I guess I should know who Jeff Beck is since he is kind of famous. Me and my friend went to the ticket office to see if there were any tickets left to either of the shows. There were only a few tickets left for Jeff Beck and it was the row in the very back of the chamber and it was quite pricey so we rejected it. However there were quite good tickets left for Iron & Wine so we decided to go with that. I think each ticket was about 80AUD, which isn't too bad for a concert in the Sydney Opera House. The concert was absolutely amazing, great music, great musicians and the sound and acoustics was mindblowing. I couldn't take any photos with my camera in there but I did film the last song of the concert with my phone, I could upload that to YouTube later on.
Sydney Opera House
The rest of the trip didn't include any audio-related events but after Sydney we flew to Cape Town, South Africa, and stayed there for five weeks. After that we had a one day stop over in Dubai, a week of free time in Prague, three weeks of work and conference in south-eastern Czech Republic and then before going back home again on the second of July I spent three days in Prague to wind down a bit.




Since I came home I have mostly been at home. A day or two every now and then working at the summer house and a couple of days visiting friends. Two weeks after I came home I got the results for my university applications. I don't know if I have mentioned it here on the blog before but my plan was to get a master of science degree in media technology at Luleå University in northern Sweden. Last year the programme got cancelled because of too few applicants. I decided I wanted to try to apply again but this year they had cancelled it before the applications started. I hadn't really thought of any other options. Of course there was the option of studying in Stockholm, but accommodation would be way too expensive there. I searched around a bit and found two other universities offering the same programme, one in Norrköping and one in Karlskrona. I decided to apply to Norrköping and at the very moment I'm sitting in my new room in Norrköping. I am sharing a three room apartment with two other guys and I just moved in today. I couldn't bring my big speakers or the subwoofers so right now I only have the Mar-Kel70 and my Denon headphones. There are not many options for speaker placement in my thirteen square meter room so I'll have to be happy with the only possible way, one meter apart and on top of a bookshelf. The bass is quite boomy but I'm planning on experimenting with the MiniDSP some day the EQ the worst peaks. The school starts on Tuesday with a two week long introduction course in mathematics. The first year will mostly be mathematics, physics and other "engineering" courses. First in my second and third year will I start with the more media-specific courses.

Friday, 16 August 2013

AKG K490 NC

So I bought a pair of AKG K490 NC last week. In September I will start my ten month long around-the-world trip and Scotland is the first stop. I decided that I need a pair of good headphones to bring with me, and my Denon AH-D2000 are way to bulky for portable use. All that was left was my Koss Porta Pro and to be honest they don't sound that good and they have zero isolation properties.

I did some reading and the best noise-cancellation headphones were of course the Bose Quiet Comfort series. They are quite expensive though and some people said the sound quality was only decent and that they couldn't be used without batteries. I looked at other brands and found that AKG had two NC headphones, the K490 and K495. The K490 being slightly smaller and cheaper and performing better without batteries than the bigger brother K495. I found a store in the city that had the K490 so I tested them with my phone right there in the store and the noise-cancellation worked really well. Sound quality was ok, not as good as normal headphones in the same price range but it was still something I could think of living with. I went home, did some more research and then ordered a pair of K490 NC from the same store, thinking I could at least leave them back if I didn't like them. I had read that the NC wasn't very great for airplane-noise so I thought I would download some airplane-noise audio samples and simulate an airplane cabin in my room. The NC worked pretty ok. I haven't tried the Bose QC-series or any other NC headphones so I can't compare them to others really.



Since I got the headphones I have been burning them in a bit playing some music on the from my also newly purchased Macbook Air. This weekend it was time to mow the lawn because finally there was a rain-free day. Normally I would just go with a pair of ear protectors but this day I decided to try the K490 NC. Turned out it worked like a charm. Without the NC on it was barely possible to listen to music. I was listening to Nils Lofgren's Acoustic Live album and lots of details were lost and I had to to play really loud and my ears were hurting after just a minute or two. Switch the NC on and the lawn mower suddenly "disappears" and the music comes to life and I can turn down the volume several steps and still hear the music clearly. With the NC on they were pretty much equal to the ear protectors I normally use (Howard Leight Leightning L1).

Update 2013-08-17:
Here are the pictures I promised.











Monday, 5 August 2013

Quick stereo recording of speakers

I was bored today so I did a quick stereo recording in my room.

The song is For My Father by Andy McKee. I set the mic at about 30cm distance from the speaker, on-axis with the tweeter. First recorded left channel only and then right channel only and mixed them together into one track.


Saturday, 20 July 2013

Objective2 headphone amplifier construction guide

Start with measuring all the resistors and labeling them.
Smallest parts first, so solder all the small resistors like this.
Add the diodes, make sure to solder them in the right direction!!! Solder the medium size resistors now too.
The IC-sockets have such short legs to it's a good idea to add them early.
Add the two big resistors at the bottom of the board. Keep 2-3mm distance between the resistors and the board since they can get warm during operation.
Add some of the small capacitors.
Add the slightly bigger capacitors on the bottom right of the board.
Add the blue capacitors.
Solder the LED first, it's important that you get it close to the board and pointing straight forward. Next att the 3.5mm sockets, they snap in to place so they are easy to solder.
Add the power socket. Solder one leg first, reheat the joint and push it in place and then solder the remaining legs.
Add the switches. This can be a bit tricky. Solder only one leg first. Reheat the joint and push the switch into place and make sure it is close to the board and pointing straight forward. If not you will get trouble with the front panel. Solder the rest of the joints when you feel satisfied with the positioning. Add the white square capacitors.
Add the volume potentiometer, try it in the case with front panel on to make sure you put it in the right position.
Volume control soldered to the board. For this kit I had to use the two row in the front.
Now add the two round brown capacitors.
As you can see in the picture there is a bridge between them. Solder the outer legs first, push them in place and then solder the bridge between them. You will need quite a bit of solder here. If you look closely you can see that the on/off switch has only been soldered as one place so far.
Add the four big capacitors. Solder one leg first, push them in place and solder the rest.
Solder the battery connectors. If you are going to mount an ODAC on the board you should only solder the two connectors to the left. If you're not planning on using an ODAC, solder both pairs. Make sure they stand straight! Solder one leg first, push to place and solder the rest.
With battery connectors on board. I will be mounting an ODAC to the board so I only soldered the left pair.
Add the ESD-sensitive parts. Be careful with these and try to avoid touching the legs. Solder smallest first and finish with the biggest. The two big ones to the left must be close to the board, otherwise they will hit the roof of the case.
Reheat ALL joints on the board. This is because when you cut the legs off components the joints may crack and provide bad connection. Reheat all joints and the solder will flow out nice and smooth. Measure all resistances and voltages according to NwAvGuy's guide on his blog. If everything measures as it should, try with a pair of scrappy headphones. Don't forget to add the opamps, and make sure you put them in the right places and in the right directions! This is very very important and triple check this before starting it up for the first time.
Don't use your expensive headphones the first time you are playing it. If something is wrong, you don't want to kill your $300 headphones. 

Thursday, 18 July 2013

Behringer iNuke NU6000 fan-mod

So today I decided to swap the fans of my Behringer iNuke NU6000 amplifier. I had to send the first one back because of some electrical buzzing sound coming from within the amplifier. Picked up the new one a couple of days ago and have been running it without fuss the since then. I had some spare time today, so why not do it and be done with it?

First remove the six screws on the top.
Remove the lid. The fan connectors are in the middle of the amplifier.
Remove the screws, four for each fan. The cover comes off too.
This is a picture of the fan connectors on the board. The cables are glued to the connectors which are in turn glued to the board. I decided to remove all the glue with a dremel.
Since the connectors are 2-pin and the fans are 3-pin you have to do some soldering. Twin the wires like this.
Solder it like this.
Don't forget this! Very important to avoid short circuits.
Fans installed. I decided to use a Zalman fan-controller.
Fastened to the side with a double-adhesive strip that came with it.
The back side. Note that I used rubber "screws" for the top two holes. They came with one of the fans (the fans are identical but I got one from a friend and bought the other).

The fans are Fractal Design Real Silent 80mm (http://www.fractal-design.com/?view=product&prod=16) and they are in fact really silent. I tried hooking it up on the kitchen table with the cover off and the only sound I heard was some faint tapping noise from the fans, probably because they were running at such a low speed. The fan controller was set to maximum speed but I still felt like they were running a bit slow. Might be the amplifier has some sort of voltage reduction on low loads. The amplifier is now completely silent. You can't hear it's on unless you put your ear to the back of it. The fan controller isn't really necessary with these fans but it had been lying in the box unopened for three years now so why not use it?

The mod itself is really easy and all you need to know is how to solder together a pair of wires.

Total time: ~2 hours. Total cost: 80SEK ($12). Would I recommend this mod? YES!