Re: Mod 2 T build

[ripcard]

Thanks Jed, I was out earlier inquiring about stains for finishing. I saw a beautiful cherry dining room table that had the look I want and the salesperson insisted that it was natural ie: no stain. So home I went and tried a wipe on poly directly on the veneer sample piece I have. The result is vey bland, almost white. Definitely not light red like the table I saw. Either they don't know what they are talking about or as he said age darkens the wood and I'll have to wait and expose the piece to sunlight for a while to get the effect. I have a hard time believing it will change colour. It will darken, but a hue change? I don't think so.

What was the stain you used on your Dynamics? Also, what adhesive did you use to hold the port in the cabinet? I was thinking silicone caulk.

[Clearwave]

I used Watco Danish Oil with a Cherry color. It was an all in one type product. Then, I used wipe on poly over that. To seal the port you can use gasket tape or caulk. I'd leave it so you can remove it for a bit, because you might want to change the port tuning to suit your tastes and room.

[ripcard]

Ok Jed, thanks. I'll look into the Danish oil. I just finished the hole for the first port and it fits in nice and snug so I'll leave it dry for now and not glue the parts together either. The length of the port specified in the drawing is overall length, correct? That is total length from edge of outside flange to edge of inside flange?

[Clearwave]

Correct, the length that I specified includes the flared parts.

[ripcard]

This being a quiet time for me work wise, I continue to find time to work on my speakers. This is a good thing. I'm really enjoying this. I can see why people find this hobby addictive. If they sound as good as others are saying when complete, I'll be thoroughly hooked.

Cut outs for the ports and binding post cups was the logical next step before sanding and finishing the veneer. I had mentioned that I was going to have a large access hatch at the bottom/back of the cabinets to be able to get at the cross over if ever needed but sourceing a suitable plate was going to take time and I wanted to move forward. I gave some thought to using MDF to make the hatch but it would probably be impossible to match the veneer. A nice 3/16" thick anodized aluminum or stainless steel plate would be sweet but having a local metal fab shop make these was going to take some time. Installing the post cups supplied with Jed's kit was not going to prevent going to a hatch later if it is required. So hopefully I didn't make a mistake or damage the cross overs when soldering the internal wiring and I can leave them like this for the time being.

I wanted a clean flush look to the back of the speaker so I routed a recess for the port.

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You can see that I had left what seems like too small of a hole in the Sonic Barrier foam when I installed it a while back. I did this deliberatly because only the tube of the port extends past the MDF into the cabinet. I just had to be careful not to rout too deep when making the cut out. The cut out opening is a nice snug fit for the outside flare but will be too small to install the assembled port from the back. I tested whether I can install the inner flare through the lower driver opening and it is not a problem as the diameter of the inner flare is smaller than the openings in my braces. Reaching in from the front down one divider to assemble the port is easy. If, and when, it comes time to do any port tuning I will have to remove the front lower RS-180. Not a big deal and this allows a press fit that will hold the port temporarily until I'm sure of the length. This brings me to an observation. The length for the 2" port Jed calls for in my modified 2T design is 5". This is the minimum length this Precision Port can be. The two flares and one coupler are all that is required to make that length. The tube and second coupler supplied are redundant for this length. So, I can only go longer if I feel a change is required. Not sure how length affects SQ so I'm not sure this is even an issue.

Having a surface mounted binding post cup with a flush mounted port just wouldn't do, so I made up a little jig to help me rout a nice even, straight recess. It worked great and the results speak for themselves.

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The four screws for the cup should suck it down flush when the gasket crushes.

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Some of you may be wondering why I'm being so anal about the backs of the speakers. Well, the back of one speaker will be in prime view from one of the entrances to the room. So a little extra effort here will make me feel better about the look.

Now I'm off to sort out my finish and get that done before I get busy with work again.

[ripcard]

Another step closer. After sanding the cabinets with 150 and 220 grit to get a nice smooth surface, I applied 3 coats of Varathane Premium Oil based wood stain. Maybe I was not leaving enough behind as I applied each coat but I found the cabinets needed the third coat to look even in penetration. I waited overnight between each coat and getting all sides done without marring the fresh stain required an extra day.

I looked for the Wadco Danish Oil with tint but couldn't find that product around here. This Varathane Premium was recomended by a couple of people I asked so I decided to give it a try. I'm happy with the way they turned out. The last coat is still drying when the pics were taken so it does appear a little uneven, especially on the front which was done last.

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I have also been working on the baffles and well...it's not going quite as smoothly. Dust control is a problem now that I'm trying to apply the final coat. I am using an old electric forced air furnace to heat the garage. It works well but without an insulated door the temp does not remain where I want it for very long before the furnace kicks in again. This causes air movement and dust to settle out before the laquer is dry. I thought I had sprayed the final coat Monday but on close inspection they were not going to buff out nicely as there are a few too many dust specs . So this morning I sanded them down again and will try to raise the temperature well beyond what I need and turn the furnace off. I'll wait ten minutes then spray. I'll give them a half hour to dry a little then bring them into the house to keep them warm while the laquer hardens overnight. This will be the sixth coat not including the three primer coats. If this does not get me the results I want, I will move forward and try it again this summer. I'll just have to mask the drivers and the rest of the cabinet off as the baffles will be glued on.

This evening I will also start applying the wipe on poly to the cabinets. I'm hoping 2 coats will be enough but we'll see. I will sand with 220 after the first coat.

Somewhere back in time I gave thought as to how I was going to stabilize these tall narrow speakers. My original idea was to have a local granite counter shop make me some bases out of sink cut outs from 1 1/4" black Cambrian granite. I was thinking a couple of inches wider all around polished up with a nice bevel or roundover. These would have added significantly to the weight of each speaker. I'm sure they would have done the job of stabilizing the towers but kind of a clunky look the more I thought about it. They also would have used up every millimeter of floor space I had for placement. They would have looked jammed in between the wall, the sub and the TV.

So, I started fiddling with making some feet that I could use spikes on to spread out the foot print a little while not looking so heavy. I even made a few prototypes out of MDF to see if I could get the shape to look decent while being strong enough to carry the weight. I'm sure if I spent some time and used some nice hardwood pieces I could have done a reasonable job but I found these and decided it was exactly what I needed (well wanted actually). A little pricy but I think they will make a big difference in the stability of the speakers and (to coin a phrase) they look marvelous!

http://www.canuckaudiomart.com/details/110097-outrigger_extender_feet_for_floor_standing_speakers/

I hope to have more pics up in a couple of days after I finish the baffles and poly the cabinets. If the feet are in by then I'll include some pics of those as well. It shouldn't be long now before I hear them.

[Clearwave]

Do you have enough Acousta Stuff to place behind the woofers and at the bottom of the cabinet?

Jed

[ripcard]

I had just enough to do all of the inside except the very bottoms. I had to use 1/2" on the front/inside wall below the RS180s though. The crossovers were going right in the bottom and fit nice and snug between all foam on the inside so I didn't think it necessary to also put some underneath. I have less than 10 square inches left of tiny little pieces.

[Clearwave]

I had just enough to do all of the inside except the very bottoms. I had to use 1/2" on the front/inside wall below the RS180s though. The crossovers were going right in the bottom and fit nice and snug between all foam on the inside so I didn't think it necessary to also put some underneath. I have less than 10 square inches left of tiny little pieces.

I usually don't place dampening on the front baffle but it can't hurt. Zaph posted a response before and after he placed tightly packed fill on the bottom of tall enclosures (resulted in less standing waves), and I'm wondering if it will be any benefit in the Dynamic Series. It's a personal taste thing, and I always encourage people to experiment with port tuning and dampening materials if any resonances are detected.

[ripcard]

Well, I hope to hear them for the first time tomorrow. After spending the weekend applying multiple layers of wipe on poly, I thought it prudent to leave them sit for a while to make sure the finish is hardened enough for handling. I will install the feet (which came friday), ports and binding post cups and hook them up to my old HK receiver in the shop for initial listening and break in. I've already installed the drivers over the last couple of evenings while they were standing there waiting for the finish to harden. The baffles were done last week so they were ok to touch.

I do have a problem that I will have to deal with later though. The poly wicked through under the masking tape and spoiled the nice smooth gloss on my baffles at the roundovers but I'll leave it for now and start the listening/tuning process before I finalize the finish. I hope to have an update with pics on the 99% completed speakers tomorrow.

Right now, it is time to go out and deal with the snow in the driveway.

[Clearwave]

Sounds good. Just make sure those Dayton woofers are wired in series and NOT parallel. The W4s are in parallel. I always get nervous that the wiring won't be right when my customers play the speakers for the first time. With good reason. It happens all the time. So triple check everything before firing everything up and use a receiver that has an protection circuit to make sure nothing is shorting etc. That way if there is a miswire or short you won't blow anything up.

[ripcard]

Yes, the RS180s are in series and the W4s are parallel. I checked and rechecked the crossover wiring before closing up the boxes so with fingers crossed I will forge ahead. Have faith brother. My receiver is an older model Harmon Kardon but not that old that it doesn't have protection. It's an early eighties Hk550i High Current that has always had a nice sound and driven various Paradigms nicely over the years so it's a known reference for me.

[Bear]

Looks great! Anything special about the veneer to use with the heat-activated glue (e.g., double-thickness, paper-backed, etc.)? Also, did you just use a standard veneer trim bit in the router?

Thanks!

Bill

[ripcard]

Thanks, Bill. I used 10 mil paper backed cherry veneer. Looking around the forums it seems most are using paper backed versions of their chosen wood species. I don't have a lot of experience with veneer, mostly laminates of various kinds, but it went suprisingly well using the Heat Lock glue.

For triming I used a standard flush trim bit with the bearing on the bottom set to a shallow depth in the router. If a side was already done that the bearing would be riding on, I protected that with masking tape. You want to minimize the sanding you have to do to eliminate any dents or gouges in the veneer as there is not a lot of wood there.

Are you starting a project?

[ripcard]

Kind of a bittersweet moment here. As I type, I'm listening to my first DIY speaker build. I don't think I'll ever buy another comercial speaker. DIY is simply too rewarding. It must be doubly so for the designer when he first hears his own design. I'm happy with the look and am amazed at the sound quality of my 2Ts. They have only been playing for a couple of hours now and they surpass anything I've ever heard. Jed, I can only imagine what your reference designs must sound like. I played around with placement in the shop a little and there is quite a difference in bass response depending on wall proximity although the bass response seems to have deepened on it's own as well with a few hours playing time. I just finished listening to Pink Floyd - Have a Cigar. Wow! I can't see needing a sub for music. The detail and clarity are also amazing. I'll continue to break them in for a couple of days with music before moving them into my home theater set up.

So here is the final build update.

After staining the cabinets and applying the first coat of poly to seal them, I glued the baffles on. By laying the speakers on their backs and using blocks in the driver cut outs I was able to apply quite a bit of clamping pressure without marking the finish in any way.

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I then hooked up and installed all the drivers using a thin closed cell foam self adhesive weatherstripping. I piloted all the crews with a 3/32" drill bit.

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I then masked the edges of the baffle and applied 4 more coats of the wipe on poly. I sanded in between with 320 grit except for the last coat. Unfortunately the tape didn't prevent some of the poly from bleeding through onto the edge of the baffle in places. So, now there is a bit of crinkle finish where it used to be beautiful high gloss. I'll likely respray the baffles when the weather gets better and I can do it outside, unless they buff out after I compound them. I don't think that is likely though. They'll have to do for now. I'm happy with the veneer finsih so it's just a matter of making sure when I do the baffles I don't ruin my veneer.

I then installed the binding post cups and ports. The heads of the screws for the speakers were too large to recess properly in the binding post cups so I found some smaller black screws in my parts bin and used them instead. The last step was to install the feet I bought to stabilize and dress up the cabinets.


Et voila.





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After hearing these 2Ts there is no doubt in my mind I'm going to complete the home theater with the Dynamic series. The surrounds will be next. I hope you enjoyed my build as much as I did.

Until next time, Rick.