Just pulled the trigger on a two-way system

[Srixon]

Joined this forum back in Feb. after lurking. I have since spent my time reading the last year's worth of build threads. Some of you guys have serious skill and reading these old threads just made my itch to build stronger.

I decided to start with a nice pair of two-way bookshelfs. Bookshelf speakers (nice ones) have always had a place in my heart. After far too much deliberation, I decided on a pair of Carerras by Meniscus. I was also considering the MoreTrix Morel set from Madisound, but the Carerras won out. If the Carerras work out, perhaps the Morels can be next.

My plan is to build a rock-solid, heavy set of cabinets for these drivers and place them on some sturdy stands. I hope I have chosen wisely and that I am rewarded with fine sound. I would love to hear how these stack up against my current towers (Polk RT2000i). Any tips and tricks you guys can lend me will be much appreciated. You can be sure I will have some questions when the kit arrives.

My soldering skills are fine having built half a dozen or more tube guitar amps from scratch. My woodworking skills are pretty good as well and I have a nice cabinet saw. Routing perfect circles and rebates will be no issue as I already have experience with the Jasper jigs. Right now, my concerns are pretty much limited to the cross-overs (I've never soldered them before) and the finish of the completed pair of cabinets (I have no veneer experience).

[TEK]

Seems like you will have a nice time building these.
Please share som pictures as you go along, will be interesting to see how you choose to attac the cabinet design.

As you most likely already know you should keep the baffel close to the designed width as changing this will affect the baffel step and the sound.
When it comes to veneering your selection of veneer to use will affect the rest of your journey a great deal.
If you want to take the wide and open road you go with PSA backed veneer of high quality. The challange with that is getting the veneer joints good in the corners. Both myself and other have experienced that the veneer draws itself a tiny bit away from the corners. You are also likely to see the back paper in the edge joints.
With raw veneer you can get perfect seems - however it is a lot harder to handle. Type of veneer also influence a lot. Thick veneer of good quality is way more easy and forgiving to apply and handle....

[Srixon]

Seems like you will have a nice time building these.
Please share som pictures as you go along, will be interesting to see how you choose to attac the cabinet design.

As you most likely already know you should keep the baffel close to the designed width as changing this will affect the baffel step and the sound.
When it comes to veneering your selection of veneer to use will affect the rest of your journey a great deal.
If you want to take the wide and open road you go with PSA backed veneer of high quality. The challange with that is getting the veneer joints good in the corners. Both myself and other have experienced that the veneer draws itself a tiny bit away from the corners. You are also likely to see the back paper in the edge joints.
With raw veneer you can get perfect seems - however it is a lot harder to handle. Type of veneer also influence a lot. Thick veneer of good quality is way more easy and forgiving to apply and handle....

I am a retired engineer and will build the baffle to within ten thousands of an inch to whatever the requirements on the plans list no matter how many attempts it may take (I also have OCD).

Regarding veneer - Something has been kicking around my head for a while now while dreaming about these speakers. I am a woodworker. I don't do veneer. The furniture I make is always solid hardwoods. Dovetails, splines, biscuits, whatever the situation calls for. It occurred to me that, for optimal driver sound, the cabinet should be non-resonant and heavy. Why can't I laminate 3/4" thick solid hardwood to 3/4" MDF, making a 1-1/2" thick material? Of course, my outside dimensions will be 1-1/2" greater, but that will be easy to take into account. As long as the internal dimensions have not deviated from the plans, what can be the harm? That way, I'm dealing with solid hardwood on all exterior surfaces and I know how to deal with that, finish wise. I have access to curly maple, black walnut, cherry, padauk, and purpleheart in widths sufficient to build these without splicing pieces together. What are your thoughts? Any issues, besides the sheer weight, that I should consider?

[Steve Manning]

I am a retired engineer and will build the baffle to within ten thousands of an inch to whatever the requirements on the plans list no matter how many attempts it may take (I also have OCD).

Regarding veneer - Something has been kicking around my head for a while now while dreaming about these speakers. I am a woodworker. I don't do veneer. The furniture I make is always solid hardwoods. Dovetails, splines, biscuits, whatever the situation calls for. It occurred to me that, for optimal driver sound, the cabinet should be non-resonant and heavy. Why can't I laminate 3/4" thick solid hardwood to 3/4" MDF, making a 1-1/2" thick material? Of course, my outside dimensions will be 1-1/2" greater, but that will be easy to take into account. As long as the internal dimensions have not deviated from the plans, what can be the harm? That way, I'm dealing with solid hardwood on all exterior surfaces and I know how to deal with that, finish wise. I have access to curly maple, black walnut, cherry, padauk, and purpleheart in widths sufficient to build these without splicing pieces together. What are your thoughts? Any issues, besides the sheer weight, that I should consider?

Another guy from Virginia ...... cool. The only issue, potentially, with the laminating idea is the real wood splitting with moisture changes, because the mdf and the real stuff are going to expand at a different rate. I have done exactly what you are talking about with padauk and did not have any problems, so who knows. I would go with a double layer of mdf and do like TEK suggested and try either some PSA stuff or straight paper backed veneer with some Heat Lock veneer glue. The few time I have veneered it has worked pretty well for me. I've never done raw veneer but I know the paper backed stuff is more forgiving of us with no veneering experience.

Steve

[BobEllis]

For baffles you might consider bamboo boards such as https://www.woodworkerssource.com/sh...uct/BAM44.html They had non carbonized (lighter color) when I bought. Stiffer, denser and better internal damping than MDF or most solid hardwoods. All good properties for a baffle. If you use sharp tools chipping and tearout is minimal and it looks pretty good under a clear coat. If you don't like the laminate look you can either paint for veneer over. I'm one of the guys Steve mentioned finding out how unforgiving raw veneer is. I should have stuck to my original plan and built a practice piece first.

Finish wise, treat veneer as you would a board of the same species. It takes stain and requires sealing the same way. You just don't have as much room to sand.

As TEK said, stick to the design baffle width. An increase of 1.5" is not insignificant and would sound a bit boomy without crossover changes. You can go thicker and just make the cabinet deeper fore and aft to keep the internal volume the same. You also need to allow some room for the drivers to breathe between the sides. If the interior width isn't at least as wide as the woofer frame diameter you'll probably impact the sound. If that means you need to go wider, a large radius roundover or chamfer can help. My experimentation showed a standard rectangular baffle with a 1.25" radius roundover acted like it was 1.25" narrower as far as baffle step response. I suspect that a 45° chamfer 1.25" deep would behave similarly, if not a hair narrower. Not familiar with your current design, so if it already has a roundover you'll have to take that into account.

[Srixon]

Placed my order yesterday afternoon. Just received a notification from USPS that my package is in transit and that I have been provided with a tracking number. So far, so good, and Meniscus receives some brownie points for keeping me updated.

[Srixon]

Update. My package arrived in good shape and in a timely manner. I've pulled the main pieces out and inspected them and, of course, there is a good deal of hardware. Some of which I will use, and some I won't. I have no intention of using the crimp on spade terminals on the speakers. My soldering skills are sufficient enough for that. Bonus gift included 4 Tootsie Rolls and two lollipops. My only thought on this is that the good people at Meniscus were worried about me spending too much time on my project and fainting due to lack of food. Thank you, Meniscus. I love Tootsie Rolls.

Here is my number one dilemma at this point. In the cross-over bag, there are six red coils that I presume are inductors. I have no experience whatsoever with these things. And, there are no markings on them for me to differentiate them from one another. In other words, how do I know their values? Can I measure them with a digital voltmeter like I do my resistors? How do they work and, more specifically, what do they do? I build guitar amps and understand resistors and capacitors, but I have no formal electrical training.

Here's a shot of the main pieces for one speaker. Scan-Speak 15W/8530K and Hiquphon OWI for the drivers and a bunch of stuff that needs soldering with it.

[sdl2112]

Nice...I look forward to your build log with pics.

Are you sure there aren't little tags on the inductors with something like 1.0 stamped on it? That would be 1mH. I see something on the inside of the darker ones. If not, contact Meniscus.

Capacitors store energy by electric field and resist change in voltage. Their impedance is inversely proportional to frequency. Inductors store energy by magnetic field and resist change in current. Their impedance is proportional to frequency.

As far as the candy...it was probably included as a package traveler to show if it got too hot.

[Alaric]

I'll be following this thread with interest. Several questions have been asked that I have wondered about. :T

[JonMarsh]

Update. My package arrived in good shape and in a timely manner. I've pulled the main pieces out and inspected them and, of course, there is a good deal of hardware. Some of which I will use, and some I won't. I have no intention of using the crimp on spade terminals on the speakers. My soldering skills are sufficient enough for that. Bonus gift included 4 Tootsie Rolls and two lollipops. My only thought on this is that the good people at Meniscus were worried about me spending too much time on my project and fainting due to lack of food. Thank you, Meniscus. I love Tootsie Rolls.

Here is my number one dilemma at this point. In the cross-over bag, there are six red coils that I presume are inductors. I have no experience whatsoever with these things. And, there are no markings on them for me to differentiate them from one another. In other words, how do I know their values? Can I measure them with a digital voltmeter like I do my resistors? How do they work and, more specifically, what do they do? I build guitar amps and understand resistors and capacitors, but I have no formal electrical training.

Here's a shot of the main pieces for one speaker. Scan-Speak 15W/8530K and Hiquphon OWI for the drivers and a bunch of stuff that needs soldering with it.

Did they include any plans or other paper work? If not, they probably assume that you will go to the web site where the design was originally developed and download the info, including crossover schematic and assembly, from their. Normally there are little stickers on inductor coils like you're showing us that have the values. Otherwise, it's one of those deals where you look at the original plans, and the highest value inductor is the big one, the middle value inductor is the in between, and the smallest is, well, of course, the smaller!

The PDF on Meniscus certainly could be better- the schematic part is inexcusably illegible. :naughty: But that may not be their fault, but Paul Carmody's, the designer, as he is the person I would expect to have prepared the PDF document describing the project.

This link will take you to a site where this kit has been built, and which also has on the landing page a link to Paul's site where you ought to be able to get more info.

http://www.midwestaudioclub.com/spotlight/project/carrera/

Good luck with your build...


(BTW, I am not engineer, but play one on TV for my day job for an international semiconductor company in Silicon Valley. no, not THAT TV show! :W )

[Srixon]

This link will take you to a site where this kit has been built, and which also has on the landing page a link to Paul's site where you ought to be able to get more info.

http://www.midwestaudioclub.com/spot...oject/carrera/

Thank you for this link. The close ups of his completed crossover assemblies are going to help me a great deal.

(BTW, I am not engineer, but play one on TV for my day job for an international semiconductor company in Silicon Valley. no, not THAT TV show! :W )

You are a very lucky man. I love silicon! Silicon, cold beer, and yoga pants. What more does a man need?

[Alaric]

You are a very lucky man. I love silicon! Silicon, cold beer, and yoga pants. What more does a man need?

Patient, understanding partners. Let's not underestimate the value of those support the phrase "Hey! I have a project!". LOL

[Srixon]

Patient, understanding partners. Let's not underestimate the value of those support the phrase "Hey! I have a project!". LOL

Amen. Been married for 34-1/2 years now. Best little woman a guy could ask for. About 5 years ago or so, the wife unit asked me to build an extension off the side of the barn to provide her goats more shade. Sixteen feet out and fifty two feet long she wanted. I designed it and built a bill of materials for the project. I then went to Lowe's and priced out the lumber, carriage bolts, and hurricane ties needed for the job. I was still working full time so, knowing the cost of the materials, I sought out three quotes. I was stunned! The cheapest quote I could get was $10k over the price of the materials!!!

I made a deal with my sweetheart that day. I told her that if I built the extension myself, I could use the money saved to buy myself a decent cabinet saw. She told me that was fine, but she didn't want the project to take longer than two weeks. Deal. I finished the extension with time to spare and purchased a Grizzly G0691. 3HP and 220 volts, full riving knife that rides with the blade, and a really nice fence. Still saved enough after the saw for a decent vacation. It's great to have a wife that supports your projects.

[JonMarsh]

Amen. Been married for 34-1/2 years now. Best little woman a guy could ask for. About 5 years ago or so, the wife unit asked me to build an extension off the side of the barn to provide her goats more shade. Sixteen feet out and fifty two feet long she wanted. I designed it and built a bill of materials for the project. I then went to Lowe's and priced out the lumber, carriage bolts, and hurricane ties needed for the job. I was still working full time so, knowing the cost of the materials, I sought out three quotes. I was stunned! The cheapest quote I could get was $10k over the price of the materials!!!

I made a deal with my sweetheart that day. I told her that if I built the extension myself, I could use the money saved to buy myself a decent cabinet saw. She told me that was fine, but she didn't want the project to take longer than two weeks. Deal. I finished the extension with time to spare and purchased a Grizzly G0691. 3HP and 220 volts, full riving knife that rides with the blade, and a really nice fence. Still saved enough after the saw for a decent vacation. It's great to have a wife that supports your projects.

Amen... hats off to you guys!

[Srixon]

Rather specific crossover question for you guys. I read a tremendous number of old build threads on this forum hoping to pick up some knowledge. Back in December of 2009, Woodworker Jon did a build and was criticized (politely) for his placement of his inductors. Something about fields and poles. He corrected the issue and went on.

Before I start gluing stuff down, please look at my suggested layout and tell me if I need to rotate any inductors. BTW, it turned out that there are identifying tags on my inductors. I missed them first time around in all the excitement of receiving new toys.

[JonMarsh]

That looks OK. The main thing is you don't want to have air core inductors near each other with the same core orientation plane- under those conditions they couple. Here, you've got them all at 90 degree angles, using all three possible orientations, and that is fine. Distance is your other friend.

You can actually get a direct read out of the coupling with fairly simple (to some) equipment- by running a signal current through one (resistor in series to limit current at low frequencies, say, 4 or 8 ohms), and with the other terminated with a reasonable speaker impedance, looking at the output voltage. Don't run the "pickup" coil open circuit, because then even a small coupled current will result in a high voltage.

[Srixon]

Thank you for the reply. I'm hoping my local hardware store has some terminal strips and that I can start gluing components to my plywood. After that it's time to solder! Believe it or not, I love soldering electronics. It's my favorite part of amplifier projects.

[Srixon]

One more inductor question - some of the leads coming off my inductors are longer than necessary. Is it possible or even permissible to trim them back? And, can I strip off the red coating myself? Will doing any of this influence the value of the inductor?

[scottvalentin]

You can trim them with no issues and you MUST strip the red coating where you solder/connect the leads. Just some 60 grit sandpaper worked fine for me or a utility knife as well. Just so the red coating is gone and you have the bare metal of the wire.

Looking forward to your listening impressions once you have them up and running!

[Srixon]

After a long break from this project, I am back up and moving on it. Using two sheets of 3/4" cabinet grade plywood for all sides, the cabinets are taking shape. I am hoping that 1-1/2" (38mm) sides and front will be stiff enough for good sound. I've used nearly an entire 16 oz. bottle of Titebond 3 on this project. I am sure I will have some questions when it comes time to stuff this thing with drivers and insulation.

[Srixon]

After routing the counterbores for the driver flanges, I use double sided tape to hold my work piece to a piece of sacrificial MDF. This way, the discs that are freed when the final hole is cut doesn't move around. Things could get interesting if that happened.

Also, due to the thickness of the sound board, I routed a generous 45 degree chamfer around the back of the mid-woofer holes.

[Srixon]

Alright, spent most of the rainy day trimming all edges flush with a bearing guided straight bit and then cut outer chamfers on my table saw. I now have another question. In my kit, there are two smaller pieces of 2" egg crate foam and one large sheet of what appears to be 1" egg crate foam. The instructions are unclear where to use which. Also, what is the best adhesive to use to adhere the foam to the insides?

I hope to begin sanding and finishing tomorrow. Cheers!

[5th element]

Looking very sharp there!

[Srixon]

Looking very sharp there!

Thank you, Ruby (I loved that movie). Now, where does the 1" foam go and where does the 2" foam go? I'm thinking because there is so much of it that the 1" foam goes on the side walls and the top and bottom and the 2" foam only goes on the back wall. I suppose I'll have to cut a hole in the back piece to accommodate the 2" port? The kit I am building is the Carrera from Meniscus. Thank you for any help you can provide, I can almost see light at the end of the tunnel here.

[TEK]

Looking good!
I can't help you with where to place the foam, but in my experience spray glue works good.

What kind of finish to you plan to apply to them?

[Srixon]

Looking good!
I can't help you with where to place the foam, but in my experience spray glue works good.

What kind of finish to you plan to apply to them?

Well, since I used plywood there are a lot of edges showing the lams. I used good plywood so there aren't any voids, but I thought I would block sand the whole thing and then prime them and paint them. I've read some build threads on here where good results have been obtained with automotive paint.

Anyone have any other ideas?

[PMazz]

bondo

[Alaric]

Bondo then block sanding will fill voids you didn't know you had. Good advice there. Make sure you use wood primer. The regular primers will get soaked in to the wood and leave you spraying more coats than you need or want to.

[Steve Manning]

I think we need to make a Sticky on how to deal with this .... it seems every few months we keep coming back to it. Could be a helpful reference.

[Srixon]

Thanks guys. Purchased a can of Bondo yesterday. Haven't used this stuff in years, but back in college I had a car whose quarter panels were made from flattened beer cans, coat hangars, old tube socks, and Bondo.

[Srixon]

At long last I have finished this project. Took advantage of a spring snowstorm to install the drivers, solder the crossover connections, and install the foam. Testing them now. They sound rather dark resting on the floor, but seem to brighten up if they are tipped backwards. They will no doubt sound better once they are resting on stands. I don't think that they were meant to sit on the floor.

A friend talked me out of painting them in favor of going with six coats of marine spar varnish. Wife likes them, but I'm still getting used to the look.

This was my first speaker project and I found it to be rewarding and fun. There are probably more in my future. Certainly now that I have all the tools!

[technodanvan]

Way to push through and finish, they look great! I'm sure they'll sound much, much better on stands.

[5th element]

Way to go with those, they look excellent!

[Steve Manning]

Nice they look nice and solid. Yep, get those things up on some stands.

[Srixon]

Nice they look nice and solid. Yep, get those things up on some stands.

They come in at 28 pounds apiece with the 1.5" thick plywood.

Ordered some nice stands off the internet. Will fill them with sand and get them installed when they come. I've read that people use something called BlueTack to keep the speakers on the stands. Will look in my hardware store for some.