DXT 2.5 build thread.

[peter_m]

Hello Everyone,
I've finally made some time to complete (almost) Jed's DXT2.5 TMM design. Thanks again Jed for this design. Many thanks to my brother in law for helping me out with the wood work. Here are some pictures of the progress. Click on the thumbnails to see the actual image.

Purchased the MDF from a local supplier where they offered the option to cut the material for me:


Starting the braces:


Having cut the baffle to the exact width (first mistake ), I had to narrow down everything else by 1/8" to allow for a flush trim bit to go around the baffle. Here is my Desk/table saw :


Router work for the tweeter:


Since my router uses a center point to make circles, I made sure to not completely go around to maintain the center piece nice and centered. I finished it of with a jig-saw and a wood file:


Finished outer layer of the baffle (front view):


Finished outer layer of the baffle (rear view):


Finishes inner layer pf the baffle (rear view):


Both layers of the baffle before glue (side by side):


Both layers of the baffle before glue (sandwiched):


Gluing & bracing of the baffle while it was drying. I was worried the glue's humidity was going to bow things out of shape. With anough braces & clamps I can proudly say it was perfectly flat:


Gluing the braces, top, bottom and sides... magic number is 8 to 10 clamps but if I had to do it again, I would not do it in one single step to avoid pieces moving as the glue makes them very slippery and mobile:


Almost finished enclosure (dog not part of Jed's parts list):


Almost finished speaker:


More to follow...

[Clearwave]

Lookin' good Peter. Keep the pictures coming. Anyway you can size them a bit bigger?

[peter_m]

The images are only thumbnails because of the large number of images I was going to post... If you click on them you get a much larger image. Is that large enough?

New images will be showing up as soon as I find my camera.... I knew I was going to loose that little thing... I wanted to show images of the interior of the cabinets with padding and all... and the listening room... soon!

Peter

[peter_m]

Here are the speakers in the listening room. As of right now, only thing missing are the round-over, veneer and a picture of the internal wall treatment.


Click image for enlargement

PEter

[Clearwave]

Looks great Peter. It looks like it might be a bit difficult to get the speakers a foot or so further apart with all that nice furniture.

[peter_m]

Moved the speakers apart a much as I could, about a 12 to 14 inch improvement. The sweetspot is much wider now, thanks. Here is a picture of the inside of the enclosure. Anything I should improve on? (I know, I tried to cut corners...)


Click thumbnail for larger view

Do you think I should put a bead of glue or caulking to even out the step between the inner and outer baffle right where it was scalloped?

Click thumbnail for larger view

Peter

[Clearwave]

You might consider using some poly fill on the back wall. About 2". I'm not sure how effective that carpet padding is either, but it might be okay.

As for your question about the caulk. I don't think you need it. You did a nice job with the baffle cutouts and there is plenty of room for the drivers to breathe.

[peter_m]

When I a/b between bare and carpeted walls there was a clear difference... even my sister noticed it instantaneously. I guess I was lucky. The poly-fill will be installed later this week as we are mother's day!

One last question. To keep all the inductors spaced out, I was thinking of placing the tweeter's x-over on the roof panel, and the woofer x-over on the bottom panel, both buried under the poly-fill. As far as I could tell, only one resistor would very mildly warm up during very loud playback. Is an insulated x-over a no-no?

Peter

[Clearwave]

Is an insulated x-over a no-no?

I certainly wouldn't pack insulation on the crossovers as a precaution. However like you said the parts don't really warm up too much in this design so if some poly fill came in contact I wouldn't lose any sleep over it. Just don't leave the house with the speakers playing 140dbs and you should be okay (disclaimer: the speakers will not play that loud).

[peter_m]

X-overs are finalized on pieces of laminated cedar no less... (recycled cigar box) No poly fill covering them at all. As for the wiring, I had to check and re-check everything about 5 times as to not make any errors. Everything was getting soldered this time. I also used a bunch of crocodile clips to heat sink all the leads on the capacitors. This speaker building business is not as simple as I though it would be. Not impossible but not as straight forward as I thought. Definitely a labor of love. One thing is for sure, I will have the most original and best built speakers in my neck of the woods, not to mention the best sounding.

Anyhow, I am glad I took the plunge and built your design Jed. I started to play the speakers louder then I have before and I can't believe how loud they get. And still no sign of the sound degrading. Even in base heavy tracks I see no reason to get a sub with these. This is debatable and depends on preference and musical choices but I know I will never get a sub for these. I am driving them with a 2x75w (4 ohm) and I think it's a descent match. It gets louder then what anyone should ever be exposed to. Other then my audiologist and my neighbors, I think everyone will love these speakers!

I won't waste time using subjective terms to describe their sound quality other then to say they sound great. They have a full sound, low listening fatigue and are overall very detailed. I also discovered that some tracks have more base then I ever imagined and that iPods should never be used as an audio source other then low level listening. The iPod just ruined the highs, noticeably more on Led Zeppelin tracks.

Next will be the round-over and lamination, but only later this summer. For now, only sitting back and listening...

Peter

[Clearwave]

Thanks for the compliments, Peter. I hope the SB kits catch on because they really are special drivers. Near Scan Speak performance at a fraction of the price.