my Hedlund horn with FE208ESigma

[Michael Speaker]

I wanted a quite different cabinet initially, but the Hedlund is too nice to be put aside. Here is where I am after almost one month of hard work. The height is only 5 feet, width is 11.3 inch. The compression chamber is different than the one in the original Hedlund, it has roughly the same volume as the one in the back loaded horn enclosure recommended for the Fostex FE208ESigma.

The picture shows it partially assembled to test the stuffing. My amp is nothing fancy, an almost 15 years old AIWA with two 40W two-way cabinets, so I can only compare the horn with the AIWA speakers. The horn sounds much much louder and the sound is incredibly crisp and clear. My wife said the old speakers now sound like they are covered with a pillow. Now we can't wait to finish the job and power both of them.

These days I finished the second one and now I am into sanding, staining, etc. They need to be ready by the end of the year. will post the final picture.

Michael

[Godzilla]

Looks great! Do you feel the 208 needs a tweeter?

[johnb]

Very nice work, I imagine it took some time.

[Michael Speaker]

The old AIWA speakers seemed OK and I did not feel the need for something else for years. I built these ones after listening to some Paradigm cabinets at an old friend when I got the bug again, but decided to make them myself because I already had the tools.
Now the Hedlund sounds so well, I do not think I can ask for more, but who knows, adding a tweeter may improve sound even further.
It might be my age too: I will be 51 soon, so my sensitivity to highs might suffer.

I will add that the drivers had more than 200 hours of break in. I did it in advance using the 60 Hz mains through a variac. I kept the level at roughly 1 watt for two days and then increased to 3 watts or so. In the beginning the sound seemed to have a lot of higher harmonics on top of the 60 Hz. After 3-4 days the sound was clearly getting better (more pure tone) and after one week it was a very warm soothing sound. Breaking in really makes a difference, now I can tell.

It took a while, but I only worked during weekends and an average of two hours per evening during the week. I bought the plywood on Nov 20th or so.

[Scottmoose]

Try a rearward-firing tweeter coming in above 10KHz or so. Doesn't have to be overly expensive, one of the more reasonably priced Fostex range ought to do. Gives good dispersion.

Best
Scott

[Godzilla]

http://melhuish.org/audio/DIYBX19.html

I place my tweeters on the back too... if you look at the pic you can see one in the background.

Placing it front facing added too much zingerroo for me.

Godzilla

[Scottmoose]

Aha! A man of taste (I favour raspberry-ripple myself)...

[wboyd]

I would love to see some plans for your version of the Hedlund...Please!

This is something that I have been comtemplating doing, but the originals are so freaking large....primarily tall. A shorter version would be just right for my space. How did you arrive at the dimensions?

Thanks,

Wayne

PS...Great Job!

[Godzilla]

Yeah, i think i might want one of those too!

It looks like your speaker is carefully balanced. How are you bracing it in back?

[Michael Speaker]

The driver sits on a double thick panel. The first is made of 3/4 inch baltic birch like all the rest and then there is an oak panel on top (also 3/4). The picture in the first post does not show the final version. The two diagonal braces are not in place yet, that is why the driver panel is wider than the cabinet.

I started with the attached drawing that is roughly based on the plans at http://www.vt52.com/diy/diypage/hedlund/hedlund.html except for the compression chamber. Then I decided to make it only 5 foot tall, so I printed it on a piece of paper and went to Kinko's and enlarged it so the height would be 5 feet.