Dynamic 4T Mk2 build

[mischmat]

Yep finally got some time and tools to start the project.
After fighting with the skill saw that cut about as straight as a drunk on a Friday night, and breaking my 1/4" straight cut bit the final front baffle is on and drying.

I must say hat's off to Jed for making such a simplistic build.

I'll get some pictures up as soon as they upload to photo-bucket. Resizing 13mpxl raw files (note to self, change setting on camera from raw to jpg) seem to take a bit of time

[mischmat]

Pictures

Pictures

Wood all cut.

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Gluing baffle 1 on, (note to self label baffles) this was the 8" baffle instead of the 6.5". Luckily I left it oversized for trimming.

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Braces in place, and standing in house.

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Front baffle attached.

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Side being pressed and held while glue dries. Figure 200lbs is enough?

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Baffle 1 cutouts.

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Baffle 2 inplace and drying.

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[Jed]

Looks like you've got a good handle on the build so far. :T

[mischmat]

Quick question Jed. Does there have to be the second piece of wood on the top?

[bbcmp1979]

looks like you're making a lot of progress there.

[Jed]

Quick question Jed. Does there have to be the second piece of wood on the top?

No, but the measurements were taken with it there so it might change the response a tiny bit. It also makes the cabinet more rigid.

[mischmat]

Ok, I made it to spec but forgot to put the top piece in. Been spending too much time in the sun. There's a space on the top for that piece still, bringing the total height to 48 3/4". Internal volume is exact to spec. I kept my tolerances withing 1/16-1/32"

[Jed]

Very tight specs and more than sufficient!

[augerpro]

Jed is the speaker using the HDS? I was looking on your site for it the other day and couldn't find it.

[looneybomber]

Yes it is. I'm slowly working on a 4cc mk2.

[Jed]

Jed is the speaker using the HDS? I was looking on your site for it the other day and couldn't find it.

I revised the Mk2 awhile ago to use the HDS tweeter, and I made various other improvements in the crossover network. You might have to refresh your browser when you go to the Dynamic Series pages to see the updated pages.

I did this when I started getting busted XT25s (the nose would arrive broken) and large variations in impedance response from one of my suppliers, plus I like the HDS a lot better.

Jed

[mischmat]

Well all put together for the most part. Tested it with drivers in place and am impressed. I do have one question that's bothering me. I have had a few people tell me different things on the tweeter, and which side is positive and negative, and it's got me questioning myself. Can you clarify?

Old vs New

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[JonP]

If you have a question, there's always the classic applying DC test, which even works for tweeters.

Get a AA battery, (don't want too much current on a tweeter, don't use a D cell) and apply it with some kind of test leads to the tweeter while watching the dome surface. Which ever way causes the dome to move out corresponds to the + on the battery being attached to the + on the tweeter. Mark the tweeter leads.

Not a bad idea to do this with all your drivers, even the clearly marked ones. It's not unheard of (but uncommon) for batches of drivers to go out of the factory mismarked.

Good to see another of these being built, it's been a while. Should be quite the rocking speaker for the moderate tower size that it is.

[Jed]

Positive is white. The tweeter should be placed on the outside for best polar response. In other words, this speaker pictured will be the "left" speaker.

[savage25xtreme]

I have the same Polks in my TV room, crazy how teeny they look next to the 4T's. How high are the tweeters on the 4T's? I know my Polks are right at ear level, how much of the problem will it be if the 4Ts tweeters are several inches above ear level?

[Jed]

I have the same Polks in my TV room, crazy how teeny they look next to the 4T's. How high are the tweeters on the 4T's? I know my Polks are right at ear level, how much of the problem will it be if the 4Ts tweeters are several inches above ear level?

Ear level is often a subjective number based on one's height when sitting in "X" identified chair. So usually that ranges from 36-42". The 4T is at the upper range of that estimate. With the Mk2, I ended up using a transfer function that maximizes vertical polar response, so if the tweeter does end up a bit over your specific ear axis it's not a big deal. The same is true for the 4CC, where the tweeter is often located under a TV, and in that case, below the ear axis.

[mischmat]

Positive is white. The tweeter should be placed on the outside for best polar response. In other words, this speaker pictured will be the "left" speaker.

It will be the left speaker. I was just testing my wiring, and since these beasts are a bit hefty to be moving, that's were it ended up in the pic.

I have the same Polks in my TV room, crazy how teeny they look next to the 4T's. How high are the tweeters on the 4T's? I know my Polks are right at ear level, how much of the problem will it be if the 4Ts tweeters are several inches above ear level?

Sounds good to me. Compared to the polks I would have to say alot of the boomy/boxy sound is now gone. They aren't producing the lower sounds at the moment due to me not having the port as of yet, but they do sounds quite nice even sealed!!

[Jed]

Once the port is installed it'll go about 40hz lower. Glad you are enjoying it (even if it is mono right now).

Jed

[mischmat]

Once the port is installed it'll go about 40hz lower. Glad you are enjoying it (even if it is mono right now).

Yea, I hope I can get the rest ordered next week.

[mischmat]

I do have a question about finishing. I did some plugging around the site but finishing isn't exactly my best area. As you can see I have a black wood grained entertainment unit. I'd like to stain or colour my speakers dark almost black while keeping the grain somewhat visible. They are finished with mahagony skin. Can somebody point me in the right direction? :scratchhead: :scratchhead:

[Hank]

I've used this on oak for a customer's speaker cabinet bases:

http://www.woodcraft.com/Product/2001718/2464/Black---TransTint-Dyes.aspx

Also, I read a woodworking forum post from a veteran woodworker who recommended India ink. Seems reasonable.

[mischmat]

Once the port is installed it'll go about 40hz lower. Glad you are enjoying it (even if it is mono right now).

Jed

You're right they do go lower with ports installed. Sound even better in pairs.

Thanks for the great design!

[Jed]

You're right they do go lower with ports installed. Sound even better in pairs.

Thanks for the great design!

You're very welcome. :T

[savage25xtreme]

pictures are needed... :B

[mischmat]

Don't mind the fudge up on the right speaker. It was one of those days and if I could do something wrong it happened. I'm toying with the idea of rebuilding them and scrapping the veneer and going just with paint.


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[savage25xtreme]

I have probably looked at this kit 20 times on Jed's website. The thing that always steers me away from it is the edges aren't rounded over. Is there room to put a round over? Would it matter at all to the tweeters FR?

[looneybomber]

At the stock width there's not much room for a round over. 8" width, and 7.25" recess for the woofers. You could always widen the box and put a round over on it, but that does change the sound a little. How much, you'd have to ask Jed or someone that's tried it.

[mischmat]

I remember it was done before. Just can't remember if it was on this site or CLD"s forums. I think a 3/8" round was used.

[savage25xtreme]

I was also thinking, you could just put a round over on the top section, paint it black with a light colored veneer that would be pretty slick.

[mischmat]

I have to redo the boxes. I had big problems with the veneer and just all around what the hell was I thinking. The right box has the mid countersink on center and not offset. There's screw-up 1. I somehow measure the bottom two woofers 1 " too low and rechecked it as right. So i cut the bottom half baffle off and replaced, mess-up 2. The veneer isn't very good since it's quite expensive for me to get it shipped to my location. The black stained one is all wavy, and messed up. I'm just going to make 2 new boxes and paint them. Should've done that from the beginning.

[savage25xtreme]

I painted my first build and wished I had tried veneer... I think they both have their own set of challenges and problems.

[Solid7]

The right box has the mid countersink on center and not offset.

Countersink??? Just out of curiosity - where do speaker boxes require countersinks???

[savage25xtreme]

I think he means the driver is recessed in the middle, not offset as it was designed by Jed.

[Solid7]

I think he means the driver is recessed in the middle, not offset as it was designed by Jed.

Oh, yes, I see. ops:

For the record, that would technically be a "counterbore" Sorry, I have a mechanical background...

[mischmat]

I think he means the driver is recessed in the middle, not offset as it was designed by Jed.

What he said. Unless I can fill the mistake somehow I may just sand prime and paint.

[ripcard]

I have probably looked at this kit 20 times on Jed's website. The thing that always steers me away from it is the edges aren't rounded over. Is there room to put a round over? Would it matter at all to the tweeters FR?

I did a Dynamic 5 channel build with roundovers. Not the 4T MkII but the width is the same. My build threads are on Jed's forum. (links in my sig)

[Jed]

I've tested the 4T/4CC with a baffle width up to 1" greater than stock (chamfer etc) and the FR remained close to the original response.

[savage25xtreme]

I did a Dynamic 5 channel build with roundovers. Not the 4T MkII but the width is the same. My build threads are on Jed's forum. (links in my sig)

very very nice build ripcard :T

[looneybomber]

I've tested the 4T/4CC with a baffle width up to 1" greater than stock (chamfer etc) and the FR remained close to the original response.

That's good to know.

[ripcard]

very very nice build ripcard :T

Thanks Gavin. I understand the Mark II sounds even better but I'm very pleased with these. For HT in my weird room, these are oustanding. I wouldn't hesitate to contact Jed. You will not be dissapointed.

[savage25xtreme]

Thanks Gavin. I understand the Mark II sounds even better but I'm very pleased with these. For HT in my weird room, these are oustanding. I wouldn't hesitate to contact Jed. You will not be dissapointed.

Only 2 things will happen if I call Jed, I will be $1500 dollars broker and I will be building some speakers

I must resist for a few months, just got married 2 months ago, paying out the wazoo for that right now :B

[looneybomber]

Only 2 things will happen if I call Jed, I will be $1500 dollars broker and I will be building some speakers

I must resist for a few months, just got married 2 months ago, paying out the wazoo for that right now :B

Hmm...I got married, then 4 or 5 mo later I bought the 4cc kit. I bought the 4T's 8mo after getting married, so you can look forward to that. :T Just wait till spring when you have plenty of warm days ahead for cutting wood.

[Hdale85]

Just build them and put them in place. Tell her it was in storage.

[Jed]

I don't want anyone to have to get marriage counseling because of a speaker purchase... :-). There will always be speakers to be had when the time is right.

Jed