Oops! Blew the last functioning tweeter

I was playing some fairly dynamic tracks at fairly loud levels (I hit 107dB at listening position about 3m from the speakers). During one of the crescendos of the track Stimela (Coal Train) with Hugh Masekela I heard some distortion noise and then the highs went away completely. If the speakers have a sensitivity of 89dB/1W as the label says and the power handling is 70 watts I must have been using a bit more than that, considering I would need ~63 watts to play 107dB at one meter distance and I was measuring the SPL about 3m away. And since only one tweeter was playing I guess it was being loaded unproperly and therefore couldn't handle as much either.

Well, that's the first time in my life I've blown a tweeter. Interesting.

Temporary speakers, with bad tweeters

Since I've stripped one of my Mar-Kel70 speakers I needed a new set to use while I finish my Mar-Kel70T. I decided to grab some old speakers I found in the cellar, some Zachry dipole/bipole (I still don't know the difference! :P). But at the first song I realise something is wrong. The cymbals and high frequency stuff only comes from the right speaker. With some help from my ears I find that three of four tweeters appear to be broken. I opened one of the speakers to see if there were any loose cables but everything seemed OK to me.

This is what they look like, another pair of drivers on the other side too.

A pretty simple filter, indeed!

Just a quick update...

Small update for small progress.

The reason for small updates is because I use my blog as a way of documenting my work for the project I have to do in school. Instead of writing it all down in a book I prefer writing it on a computer and sharing my work and progress with the rest of the world. Sharing is caring.

So, today I decided to fix the internal cables to the Mar-Kel70. I'll use one strand of CAT5 internet cable per terminal. So in total two strands per speaker and four in total. I've cut the cables to right length but I'll still have to strip the insulation. I'll do that some other day, but first I'll have to figure out how I can effectively sand down the brace cutout more so the driver doesn't rest on it.

Pictures of the CSS EL70eN

Here's some pictures of my CSS EL70eN, modified by David Dlugos at http://www.planet10-hifi.com/

Winter is coming...

Winter is truly coming now, it was -18c this morning when I had to walk to school. Luckily as a Swede I know how to dress properly to avoid freezing to death.

This week I'm taking a week off from the gym, for two reasons. The biggest reason is to give my body time to regenerate from several months of working out 5-7 times per week. The other reason is to have time and energy to build speakers. My dad will be away for the whole week but I will try to prepare everything so we can glue the baffles and top panels during the weekend. That means I have to drill holes for terminals and drivers (done, but might not be large enough), prepare internal cables (probably going for cat5 cables), makes sure all panels are same height (working on it) and that the drivers fit well to the brace (also working on it).

Cutting the damping material was harder than expected.

Apparently the brace was sticking out a bit so there was a little gap between baffle and the side panels. Here in the picture the baffle is on its edge just to demonstrate the size of the gap. I had to sand the brace down a few millimeters.

Removed the driver and terminal on one of my Mar-Kel70.

Making sure the holes are right

Time to do the same with the terminals

Mark the holes for drilling

As I mentioned earlier I had drilled the holes as well, but my camera ran low on battery so I'll take photos of that some other day or just include them in the next update.