SST8 Finished! Link to pics

[kingdaddy]

Well, after nearly 500 hrs over the past 6 months of obsessive working and draining all my monitory recourses there finally done. I had no idea as to what the finish should look like, I couldn’t get an idea in my head of what I wanted it to look like so I just kept experimenting with different finishes and at the last minute I decided to add the oak inlays, boy did I bite off a chunk there, anyway they kind of look like turtle shells at first so I changed the finish one last time to a lighter shade for more contrast and I’m happy with the effect, and they integrate well into my all Red Oak trimmed living area so I’m quite happy with the looks, although I’m sure some will find them grotesque or just too weird.

Just as soon as I fired them up and got a good listen to wet my appetite and began the arduous task of fine tuning the crossover I turned off all my equipment (Sony TA-E9000ES Pre Amp and matching Amps) to wire in the AR correction networks that Peter has been so gracious to help me with (Thanks Peter at AR) Unfortunately as luck would have it when I turned it back on there was no sound, no output from the Pre Amp at all, It’s done this before but started working after I cycled it on and off again, However this time it was for good. So I opened it up and found two bad transistors (Q108 and Q110), I then posted this on the dedicated TA-E9000ES Forum that I frequent, turns out this is a well documented problem with this unit and within a day Djay the moderator sent me information regarding a service bulletin for the very problem I have and notes “Q108 overdissipated”, and then states that to repair you need to replace a 4.7K 1/10 watt resistor (tiny chip resistor) with a 1W version to protect Q108, I’d like to see how they expect you to shoehorn a 1W on tiny flat pack pads that are .05 spaced (Thanks Sony Engineering).

Anyway, I should have my system up and running in a few days and be able to see if the AR Conjugate filter helped or not, and continue tweaking the Ports and playing with the mid angles and tweeter position.

As soon as I get them fine tuned I’ll try some actual acoustic measurements and some gated pulses to set relative acoustic offset.

My SST8 Speaker Project

http://64.33.91.28/kingdaddysst8/index.html

[Jean]

You are one crazy son of a !!!!! No really, they are something, reminds me of Aliens movie for some reason ?

Is that your final speaker "stand" or are you going to do something about it ?

curious

[kingdaddy]

The solid oak stand's that are in the Pictures are the final stands, I would never attempt to build anything like them again, they were much moor difficult and expensive than they look, I wore off all my skin hand sanding all those corners, nooks and crannies.

KD

[St= Z]

Well.. I'm impressed.

What material did you use for the speaker cabinets?

[kingdaddy]

You asked fo it.

The cabinets are made from 3/4 MDF and a tar slurry (very thick) between another 3/4 batten, the inner battens were attached with screws until the tar completely cured (about 3 weeks) then the screws were removed, so the internal battens will float somewhat. All joints are glued and no wood screws are used anywhere in these speakers, only 8 each 10-32 bolts into locking nut-plates and poly glue to attach the front baffles, the baffles needed to be removable right up till the last minute, then they were glued and bolted to hold the baffle in place, then the recessed holes for the bolts were filled in with bondo. Each mid enclosure is minimum 1.5 thick and the baffle is 4 inches thick with the back side bowled out extensively for breathing room. After the baffles were permanently attached another coat of tar compound was applied (Leak Stopper from home depot) so it goes like this; ¾ MDF, Tar, ¾ MDF, Tar. Each mid enclosure weighs about 40 Lbs and the internal volume is exactly.26 cubic foot (used water to measure volume), and flared ports out the back with a 90° elbow on the end of the port behind the driver. The Tweeter enclosure is telescoping (moves for and aft 1.25 inches) PVC mounted over a fixed PVC tube that is embedded into a 2.5 inch square block of oak then the fixed tube is filled with expanding foam for further isolation.

[St= Z]

So its a series of trapezoid mdf peices bonded with thick seems of tar, which are rounded down and shaped?

You should be proud of your work.

How do they sound?

[kingdaddy]

There is a little glair still in the Tweeter that I'm trying to compensate for with a conjugate filter, but other than that they sound outstanding in the midrange area the clarity and detail are astounding, and transients are lightning quick (helps to not have any passive components between the mid/woofers and the amp output) , Imaging and soundstage are also very strong but I haven't experminted with the placement yet so I think it will get better with some fine tuning. Later I will do some gated responses and get the relative acoustic offset adjusted then I believe everything will come together.

[grataku]

Kingdaddy,
nice work, although I detest the look of oak. How did they get to be so expensive? $2600??

[kingdaddy]

The whole cost is no object idea is always a bad one and it will get you into more trouble than you know, and that was my focus at the beginning so a lot of waste incurred .I built at least 4 different enclosures of different shapes and sizes, I even had a composite sphere made to test against the tapered octagon to see which measured better, turns out that the Tapered Octagon sounded as good and measured better than the sphere. Anyway I don't have a parts list breakdown and I don't know if I could ever generate one, there were too many trips to Home Depot to count, but just to give you an idea the oak planks for the stands were $250 just for the wood and over $200 for the finish of the midrange modules, the clamping knobs that hold the modules to the stands were $130 and another $100 for the spikes and mounting materials, I used 6 different glues and every tool I could get my hands on, even bought a special “Standard Glue bit” for my Router table ($50) to join the 12” oak planks together and make 20” wide planks for the stands, and even though there are no wood screws in the speaker at all I still used a estimated $60 worth of wood screws and misc hardware on the more than 5 different jigs I had to make. As I said the whole cost is no object idea turned out to be a bad one. I also bought some more tools that I didn’t add in the estimated price to build these which would be another $700. The drivers were aprox $420 and I'm using a Marchand XM-9 Active crossover (aprox $350) I spent over $70 on sandpaper alone, I could go on and on, and now that I think of it, it may be even more expensive than I thought.

[CHRIS8]

Kingdaddy...... ready to start on a new project soon? LOL

I figure that to outdo yourself next time around you will be needing to find a good used cnc mill, less you spend half a year constructing the cabinets. Don't worry...it won't cost that much to build the cabinets if you do not count the cost of the mill. Just don't let on that you had to take out a mortage to pay for the new tool. LOL.

Good luck!

-Chris