The DIY Super Center Channel Thread

Early B.

As many of you already know, Ben and I have been working feverishly to complete the build for a super center channel based on a kit I purchased (more on that later...). I'll have to post more pics and provide my first impressions of the sound this evening, but I thought I'd tease you with a picture of the finished product. I have nicknamed it, the "Rock Box" for three reasons.

Enjoy the pic...

Conradicles

Nice..I am thinking about making one myself to match my SDA's...Not quite that big though! Good job guys.

Early B.

So why did I decide to build a super center channel? Well, the center channel speaker is the most important speaker in an HT setup because it carries the majority of the sound and all of the dialogue. I realized several years ago that the typical MTM center channel configuration, regardless of brand or cost, was inadequate in conveying the richness of HT. This is particularly important with bass. Most center channels are rated at 50Hz or higher. That’s not good enough.

I believe a good center channel should be able to dip into the 20’s. Here’s why: the value of implementing an HT system is to replicate, to the extent possible, the “you are there” phenomenon. You want to be part of the action. So if a gun shot goes off, it should sound realistic – just like you are in the scene alongside the actors. In other words, the sound should have plenty of impact and be as dynamic as possible. Sorry, folks, but that ain’t gonna happen with a wimpy center channel. The center channel should be the second biggest, baddest speaker in your arsenal (with your subwoofer being #1).

With that said, I wanted to build the mother of all center channels. Of course, no store or retailer had what I was looking for. The closest one was a center channel designed by PBN Montana. (http://www.montanaloudspeakers.com/loludspeakers/spc.html) They build huge speakers and have huge price tags, as well. Fortunately, with a tip from GV#27, I stumbled upon the Dynamic 4CC kit and placed my order.

Early B.

There’s another important reason for the value of pursing a DIY project. Consider this: 100% of the cost of this center channel went into materials. Contrast this with a product purchased from a retailer. I’m guessing about 10% of the cost went into materials. The other 90% of your money goes to pay salaries, middlemen, marketing, overhead, profit, etc. So if you pay $300 for a DIY project, it could conceivably retail for 10 times what you paid, or $3,000. Plus, with a DIY design, you are likely to purchase higher quality parts and you have the benefit of customizing it any way you like.

Early B.

The designer of the Dynamic 4CC is Jed Kunz, a prolific DIY speaker designer with award winning designs. Check out his website: http://clearwaveloudspeaker.googlepages.com/

As a novice to DIY speakers, Jed was very patient and explained the build process very well via a flurry of e-mails. He seemed genuinely interested in making sure I had a very positive experience with his design. In fact, I’m seriously considering doing more business with Jed in the coming months.

Upstatemax

I have that same TV. :cool:

On that note, how much vibration is the TV getting from the CC?

The vibration could kill the bulb in that TV...

Early B.

OK, so how does it sound? Once Ben and I completed the build, he hooked it up to his system and we were astonished at the sound. It was very powerful and clear with a huge soundstage. We were very impressed and I was anxious to get it home and hook it up to my system. Since the speaker weighs at least 100 pounds, I couldn’t tuck it under my arm and walk out the door. We had to use a hand truck to move the speaker.

When I got it home around midnight last Saturday, my wife was waiting for me. She loved the look of the Rock Box and had no problems with it being naked in the den, although I prefer a grille, particularly for times when children are in the house. They won’t be able to resist touching the shiny midranges, phase plugs, and Vifa nipple.

Anyway, we popped in the demo DVD, then a music CD. Let’s address music first. We put on Sarah McLachlan’s live acoustic CD and I had to put my ear against the front speakers a couple of times to make sure they were not on. In spite of the center channel being horizontally placed and near the floor, the sound was as good as, if not better than, my 2-channel system. The soundstage, detail, and tonal quality were the best I have heard in my home. Period. That’s with one speaker with music being played on a DVD player and powered by a multi-channel amp!!!

Of course, many of you will doubt what I’m saying, but I don’t care. I’m telling you what I heard. The music was seamless and it was surrounded by a breath of fresh air. I heard it, Ben heard it, and my wife heard it. All of us agreed that this center channel was incredibly good. In fact, we were so excited that we called Jed and thanked him personally for designing such a great speaker. In addition, I’m entertaining the possibility of purchasing the Dynamic 4T kit and build the floor standers to complement the center channel. That’s how good it sounded.

OK, so how does it sound with HT? We watched the Dark Knight last night and let me tell you – it was, by far, the best HT experience we’ve heard (in spite of the movie just being OK and too damn long). I know I’m not going to do justice in trying to explain the improvement in sound, but I’ll try. Let’s begin with the front soundstage. If you go into a good movie theater, you are surrounded by speakers. However, in your home you have 2 or 5 or 7 speakers. That’s fine, but ideally you would probably want a wall of speakers all around you, but especially in the front because most of the sound is coming from in front of you. The value of a 4-foot long center channel speaker is its ability to project a wider sound, thus making the front stage appear as one speaker, not three. This provides a greater sense of the “you are there” thing I talked about earlier.

More importantly, the dynamics and impact are off the charts. In the past, I always felt that my many HT configurations suffered from anemia. The main source of the problem was the wimpy MTM center channel. Listen carefully folks – the center channel is much more important than most people realize. Let me offer an analogy. When you print in color on your inkjet printer, the black ink is used to create many of the colors. If you remove the black ink cartridge and print in color, the colors will not be correct. Similarly, a center channel anchors the sound – it aids in the production of sound from all of your speakers. For instance, when the rear speakers fire, they often get assistance from the center channel. So when the Rock Box was introduced, it not only improved the sound coming from the center, but the entire system has been greatly enhanced. My system doesn’t sound like it’s attempting to emulate the movie theater experience anymore. It IS the experience.

Early B.

Upstatemax wrote: »

I have that same TV. :cool:

On that note, how much vibration is the TV getting from the CC?

The vibration could kill the bulb in that TV...

A good speaker cabinet is designed NOT to vibrate.

Early B.

I will post a few pics of the build process later today...

zingo

That think looks amazing, and I'm sure it sounds even better! The construction looks pro and it makes the perfect TV stand.

Early B.

As you may know, I’m a huge proponent of bass all over the place. What’s missing in most HT systems is some serious bass from the center channel. One of the main reasons I wanted to build a bigger center channel is to get more bass. In this case, the center channel is set to SMALL and crossed over at 60 Hz (it’s the lowest setting on my pre/pro for the center channel). I wanted to set the center channel to LARGE, but when I do, for some reason the pre/pro automatically sets the surrounds to LARGE, but I don’t want to do that, hence the SMALL setting for the center channel, at least for now. Emotiva will unveil its new UMC-1 pre/pro soon so hopefully I’ll be able extract even more bass from the Rock Box than I’m already getting.

Upstatemax

Early B. wrote: »

A good speaker cabinet is designed NOT to vibrate.

True, but that does not mean it's not getting ANY vibration from the speaker. I have worked with those bulbs for years, they are VERY sensitive to vibrations. Plus when they go, it's a solid $200-250 to replace the bulb...

Just a friendly heads up.

rdb2001

It looks great and at the price you built it at is amazing. Glad things turned out good.

Early B.

I wanted to take a moment to personally thank Ben for volunteering his time and expertise to this project. We spent an entire Saturday (12 hours actually) building the Rock Box. He was just as excited as I was to get started on the project, and we both shared in the exhilaration of its completion. Our jaws dropped simultaneously the first time we heard it. There are really cool people on this forum, and Ben is a great Polkie and a great person.

Early B.

Upstatemax wrote: »

True, but that does not mean it's not getting ANY vibration from the speaker. I have worked with those bulbs for years, they are VERY sensitive to vibrations. Plus when they go, it's a solid $200-250 to replace the bulb...

Just a friendly heads up.

Thanks, but the TV should fear my subwoofers more than the center channel 'cause they cause the whole room to vibrate.:eek:

FWIW -- I've also had this TV resting atop a couple of previous, lesser built center channels for the past 2 years with no problems.

mmadden28

Awesome job guys!! Perhaps that may be my next DIY project. Looking forward to the build pics.

Any timbre matching concerns?

ben62670

Well I would like to thank Brad for this experience, and it was a pleasure meeting his lovely wife. I was going to ask if she had a sister, but I didn’t want to get tossed out on my ear:D I went over to his house last night to do a little finishing, and install a two circuit dedicated outlet for him. This speaker when just running as a center presents a huge sound stage. Like Brad said it sounded like the floor standers were on. The first music selections were live female recordings so it did not contain any stereo information. Even running just a DVD player as the source through EMO gear it sounds fantastic. It seriously gave me goose bumps. The underling detail this speaker was able to reproduce was uncanny. I questioned the build considering that it was a kit from some guy off the internet, but after hearing it I was completely floored. There is no audible transition from driver to driver. It is so seamless that you would not believe it is a 3 way. Brad has got to let his VMPS's go:eek:, and get the kit for the floor standers. I have heard a lot of gear in different HiFi shops from entry on up. What this speaker did was awe inspiring. I knew I liked the Vifa ring radiator, but was unsure about titanium coned mids, and the Dayton RS woofers. Fears are relieved. Before Brad took it home we hooked it up to my system here, and the bass was phenomenal. Brad thought for sure that one of my SDA's was on:D My hats off to the designer of this speaker:)
Ben

Early B.

ben62670 wrote: »

The first music selections were live female recordings so it did not contain any stereo information.

BTW, Ben -- the second female recording we listened to was not live. It only appeard to be so. It takes a damn fine speaker can pull a trick like that.

treitz3

Glad to hear that you like it Brad. As for upgrading the mains? You can't do that. Remember, you are done with audio and have been. Again.....

........and again..........

........and again..........

........and again..........

........and again..........

........and again..........

:eek:

Doug_D

I just wanted to chime in and say that I built the 4T's and they are simply amazing I will be adding the 4C center and 1S surrounds as well as a sub in Jan. I will also be adding a new amp or 2 and a UMC-1 to hold me over until the XMC-1 comes out. I love Emotiva and I love Jed's speakers this is the second design of his I've built. Here is a picture of my speakers.

treitz3

Welcome to CP! Nice.

Early B.

treitz3 wrote: »

Glad to hear that you like it Brad. As for upgrading the mains? You can't do that. Remember, you are done with audio and have been. Again.....

........and again..........

........and again..........

........and again..........

........and again..........

........and again..........

:eek:

To be honest, I have mixed feelings. There's no way in hell I was going to consider trading out my wonderful VMPS speakers anytime soon, but the improvement is so compelling that I may be "forced" to do it. Even my wife wants me to trade them in favor of the DIYs, and she has never expressed that level of interest in my speaker upgrades.:cool:

Face

So when are you going to stop messing around and build the matching mains?

EDIT: I didn't see the above post.

Early B.

Doug_D wrote: »

I just wanted to chime in and say that I built the 4T's and they are simply amazing I will be adding the 4C center and 1S surrounds as well as a sub in Jan. I will also be adding a new amp or 2 and a UMC-1 to hold me over until the XMC-1 comes out. I love Emotiva and I love Jed's speakers this is the second design of his I've built. Here is a picture of my speakers.

Sweeeetttt!!! Gotta love those speakers, dude. Thanks for posting.

I'm into Emotiva gear, as well. Great bang for buck. Is that an XPA-3 on your shelf?

Doug_D

Yes I currently have an XPA-3 and plan on adding either the XPA-1's or an XPA-2 depending on how much cash I have lol. The speakers are simply amazing best speakers I've heard for sure. I've heard a few other DIY designs as well and these easily top them. I'm sure I'd have to spend many thousands to get something close to these in a commercial design. Everything you said about the center is the same way I feel with the towers. They are extremely well balanced and the midrange is one of my favorite parts of these. I built Jed's Lineup Maxx last time and I loved the midrange in them. The tweeter was pretty good but I always wanted more as far as the woofers went. That's when I talked to Jed about these and they certainly fill all my needs! Spectacular speaker to say the least.

Early B.

Doug_D wrote: »

Yes I currently have an XPA-3 and plan on adding either the XPA-1's or an XPA-2 depending on how much cash I have lol. The speakers are simply amazing best speakers I've heard for sure. I've heard a few other DIY designs as well and these easily top them. I'm sure I'd have to spend many thousands to get something close to these in a commercial design. Everything you said about the center is the same way I feel with the towers. They are extremely well balanced and the midrange is one of my favorite parts of these. I built Jed's Lineup Maxx last time and I loved the midrange in them. The tweeter was pretty good but I always wanted more as far as the woofers went. That's when I talked to Jed about these and they certainly fill all my needs! Spectacular speaker to say the least.

Man, I love to hear your impressions of these speakers once you add the center channel. You said next month, right?

I also noticed that you built your tower speakers using a curved cabinet design. Did you spec the cabinet yourself or did jed provide the plans for it?

Doug_D

I did the cabinet design my self. Jed has talked about adding plans or a finished speaker option for the curved side but hasn't really said much on it? I know the 1S surrounds are going to be in the parts express curved MTM cabinets. I will be ordering all the parts for the Center and Surrounds and what not sometime in Feb when tax returns come.

More on the cabinets, I started a design in Solid Works (cad program) so that I could have the majority of the parts CNC'd but I wasn't the greatest with Solid Works so a friend from another forum ended up helping me out with it. There is a build thread of my speakers on Jed's forum if you care to look. It was a bit of work but they turned out great. They will eventually be stained and clear coated.

Doug_D

I should also mention my cabinets are quite a bit larger then Jed's. Jed's are something like 50 liters while with mine I wanted to extract the most low end I could out of it so they are something like 80 liters. So mine will play a good bit lower then Jed's cabinet design. Not that Jed's are any slouch in the bass department I'm sure they are still extremely impressive as I'm sure you know from the center build. My center will be the standard enclosure as I don't feel like doing another curved thing haha!

Early B.

Doug_D wrote: »

I should also mention my cabinets are quite a bit larger then Jed's. Jed's are something like 50 liters while with mine I wanted to extract the most low end I could out of it so they are something like 80 liters. So mine will play a good bit lower then Jed's cabinet design.

I find it interesting that you decided to make the cabinets larger, as well. If I were going to build the 4T's, I'd make the cabs larger -- at least 12 inches wide. I like the curved design, too.

I almost made the Rock Box 12" high, but decided against it after consulting with Jed.

Early B.

The Rock Box is based on the Dynamic 4CC kit from Jed Kunz of Clearwave Loudspeaker. I made one approved modification – the original design is 42” in length but the Rock Box is 48”. I wanted to make it longer to fit the length of my TV and to get more bass. This brought the box down a bit to 36 Hz and, of course, with room gain we’re looking at the very low 30’s. The dimensions are approximately 48”l x 16”d x 9”h.

When I first received the kit, I was struck by the sheer size of the crossover. The crossover weighs in at a beefy 4.2 pounds and is built point-to-point on a 5.5” x 9” MDF board. (By the way, the drivers, crossover and other parts weigh about 35 pounds, which is the entire weight of a typical center channel speaker. The Rock Box probably tips the scales at around 100 pounds.) The crossover uses Dayton caps. Two 2” ports are on the back along with a set of high quality binding posts that Ben provided.

We decided to finish the speaker with Formica instead of paint or wood veneer in order to save time and to make it more durable. It’s gotta be able to bear the brunt of a TV, and paint or veneer would be more vulnerable to dings and scratches. The Formica looks like granite, hence the name “Rock Box.” We also cut another corner by not flush mounting the drivers. In addition, we did not build a grille because the Rock Box looks sexy enough without it. Oh, I almost forgot – we placed the crossover behind one of the woofers instead of the sealed enclosure behind the tweeter/midranges where it was supposed to go in order to access it once the cabinet was sealed. Luckily, this was a good move because we needed to make a minor tweak to the crossover after the enclosure was assembled.

The cabinet is constructed of ¾” MDF with a 1.5” baffle. There are four braces. As always, the challenge is making straight cuts and getting everything to fit perfectly. Of course, having all of the necessary tools is important, too, and Ben and I had most of what we needed. One of the mistakes I made in the assembly is attaching the Sonic Barrier before the cuts were made for the drivers. The sawdust got all over the Sonic Barrier and we had to spend a few minutes using a vacuum cleaner to suck out as much sawdust as we could. Please, wear a mask if you’re gonna cut MDF. The pics show Ben's car showered with sawdust.

Once the Rock Box was maneuvered into position, I placed a set of isolation pucks underneath it so it wouldn’t rest directly on the fireplace hearth.

clearwave

Early B. wrote: »

we placed the crossover behind one of the woofers instead of the sealed enclosure behind the tweeter/midranges where it was supposed to go in order to access it once the cabinet was sealed. Luckily, this was a good move because we needed to make a minor tweak to the crossover after the enclosure was assembled.

Hi, I'm the owner of CLD, and just thought I would chime in to say thank you for the wonderful review!

Now, about that sealed enclosure you mention in your post in the quote above. That section is actually not sealed. The partitions should actually have a cutout to make a passage that leads from each woofer section behind the completely sealed midrange chamber. I heavily stuffed that area with poly fill and you can place the crossover there if you want and still have access to it. This adds a few extra liters to the woofer section as well. I just wanted to clarify the construction, just in case anyone else is wondering. Putting the crossover where you did is a smart move though.

Great build!

Regards,

Jed
Clearwave L. D.