New Project

[catacon]

Hey Everybody,

I am currently building a set of RS180 Modula MT's that I hope to have done by the end of the month. After I finish those, I want to build three more speakers to use for fronts and a center. My choices right now are the Natalie P's and Modula MTM's. I want speakers that will match the MT's the best. I don't need a whole lot of bass from the speakers, as I have a nice subwoofer to cover that. I understand that there is a Modula MTM center channel that use a different tweeter and crossover, can the Natalie P be used as a center channel on it's side, or does it need a different crossover? I was kind of turned away from the MTM center because of the $164 tweeter. Is there another center channel that will match the MTM's or Natalies?

Thanks!

[Brian Bunge]

I don't know which will match the Modula MT's the best, but I do know that you cannot use the Nat P or Modula MTM on it's side as a center. Jon will be designing a 3-way center that will be ready around the end of June I believe. It will use the same size enclosure as the Modula MTM.

[catacon]

Is there an estimated cost for this center? I will probably build the left and right channels first and then the center. What are the major differences between the Nat P's and Modula MTM's? They seem pretty similar to me.

Thanks!

[PoorboyMike]

Is there an estimated cost for this center? I will probably build the left and right channels first and then the center. What are the major differences between the Nat P's and Modula MTM's? They seem pretty similar to me.

Thanks!

According to ThomasW, you would need very high end equipment to tell the difference between the NatP and the ModulaMTM.

[ThomasW]

Is there an estimated cost for this center?

We'll know that for sure the end of June when the first one is built. It will likely be as expensive as the current MTM center with the $pendy tweeter, because it's a 3-way. This means money for a dome mid and basically double the XO components of the MTM 2-way.

[catacon]

What is the approximate cost for each (Nat P and MTM)?

[ThomasW]

That information is listed in BOM's of the respective threads.

[catacon]

If my math is correct, the Modulas will cost $680. Is that about right? Here is the BOM I put together.

Modula MTM BOM

1.2Mh Inductor (L1) $20.57 x2 $41.14

.6mH Inductor (L2) $15.46 x2 $30.92

47uF Capacitor (C1) $13.09 x2 $26.18

30uF Capacitor (C2) $9.52 2 $19.04

3uF Capacitor(C3,C6,C9) $2.25 x6 $13.50

5uF Capacitor (C5,C6) $34.08 x4 $136.32

10uF Capacitor (C5,C6) $4.48 x4 $17.92

330uH Inductor (L3) $11.51 x2 $23.02

1mH Inductor (L4) $18.83 x2 $37.66

82uF Capacitor (C7) $19.75 x2 $39.50

1.5mH Inductor (L5) $7.62 x2 $15.24

68uF Capacitor (C8 ) $18.43 x2 $36.86

10ohms Resistor (R4) $3.50 x2 $7.00

8ohms Resistor (R5) $3.50 x2 $7.00

4ohms Resistor (R6) $3.50 x2 $7.00

RS180 7" Driver (D1,D2) $32.70 x4 $130.80

27TDFC Driver (D3) $32.45 x2 $64.90

4x8 MDF Sheet $20.00 x1 $20.00

Total ------ - $680.00

[TacoD]

Those resistors are very expensive, $3.50 a piece?

[ThomasW]

Don't know about the math that's between you and your calculator...

Since you didn't reference the supplier comments are problematic.

Not really sure anyone building this speaker needs to spend $20-$18ea for 1.2mh-1.0mH inductors, or $20 a pop for 68-82mfd caps.

I know Jon lists high-end components, but there are less expensive parts that will do the job fine.

Unless you're running all Mark Levinson or similar electronics, look at the PE Dayton brand caps and the GE closeout caps from Madisound. Several smaller value caps can be paralleled to make a single larger value cap.

Look at the Jantzen inductors.

And the Dayton non-inductive resistors are a good buy..

[catacon]

Yeah I just used the PE part numbers that Jon listed. For the MT's that I am building, I used GE caps and Jantzen inductors, so I may do that again.

Are there any "budget" BOM's out there? I'm feeling kind of lazy.

[catacon]

Well, I worked out a new BOM and was able to save myself about $230. One question, though: Instead of buying 1.2mH Inductors, I put down 1.25mH inductors. Will .05mH make a difference?

I attachted the BOM. It's an Excel Spreadsheet.

Thanks!

[ThomasW]

Modula MTM Budget Bill of Materials

Parts Express
Part Unit Price ($) Quantity Total Price ($) Part Number
3uF Capacitor-1.67-6-10.02-027-418
10uF Capacitor-3.15-4-12.60-027-428
30uF Capacitor-7.88-2-15.76-027-440
47uF Capacitor-13.09-2-26.18-027-600
68uF Capacitor- 18.43- 2- 36.86- 027-608
82uF Capacitor- 19.75- 2- 39.50- 027-612
1.5mH Inductor- 7.62- 2- 15.24- 255-052
4 Ohms Resistor 1.25- 2- 2.50- 004-4
8 Ohms Resitor 1.38- 2- 2.76- 004-8
10 Ohms Resitor 1.38- 2- 2.76- 004-10
RS180 7” Driver 32.70- 4- 130.80- 295-364

Sub Total 294.98

Madisound
Part Unit Price ($) Quantity Total Price ($) Part Number
5uF Capacitor- 0.75- 4- 3.00- n/a
.33mH Inductor- 5.10- 2- 10.20- n/a
.6mH Inductor- 7.50- 2- 15.00- n/a
1.0mH Inductor- 9.60- 2- 19.20- n/a
1.25mH Inductor- 10.50- 2- 21.00- n/a
27TDFC Tweeter- 32.45- 2- 64.90- n/a

Sub Total 133.30

Other
4x8 MDF Sheet- 20.00- 1- 20.00- n/a
Glue, etc.- 10.00- n/a- 10.00- n/a

Sub Total 30.00

Total 458.28

[ThomasW]

You're okay with the 1.25mH inductor as long as the DCR is close to the recommended one

[catacon]

I can't find the DCR for that inductor, Madisound doesn't have any info on the Sidewinder inductors.

I probably won't buy the crossover parts for a while due to finalcial issues, but I will be building the cabinets during the next two weeks. Will the new center channel be based off of the PE 1cu ft cabinet? And both the NatP and Modula MTM are based off thatg correct?

Thanks!

[ThomasW]

Yes the new WMTW will use the same 1 cu ft cabinet as the MTM/NatP.

It will work in all locations of a multi-channel speaker system, so it's not just a center channel.

My cabinets were delivered about 20 mins ago, so it's time to make sawdust... :T

[catacon]

Ok, that will make this easy in case I change my mind about what design I'm going with.

Yeah, I'm picking up some more MDF tomorrow, so my garage will be messy the next few weeks.

[catacon]

What size should the tweeter backing plates be?

[Mazeroth]

"5uF Capacitor (C5,C6) $34.08 x4 $136.32"

Where can I get these? :W

[catacon]

http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=027-730&CFID=12629729&CFTOKEN=39792834

I opted for the $0.75 GE caps from Madisound, though.

Here is an update of the BOM, I just added ports.

    Modula MTM Budget Bill of Materials            Updated 6/14/2007
                
        Parts Express        
Part    Unit Price ($)    Quantity    Total Price ($)    Part Number
3uF Capacitor    1.67       6       10.02                    027-418
10uF Capacitor    3.15       4       12.60                 027-428
30uF Capacitor    7.88       2       15.76                  027-440
47uF Capacitor    13.09       2       26.18                   027-600
68uF Capacitor    18.43       2       36.86                  027-608
82uF Capacitor    19.75       2       39.50                 027-612
1.5mH Inductor    7.62       2       15.24                 255-052
4 Ohms Resistor    1.25       2        2.50                  004-4
8 Ohms Resitor    1.38       2        2.76                  004-8
10 Ohms Resitor    1.38       2        2.76                004-10
RS180 7” Driver    32.70       4       130.80                295-364
Precision Port 2”    9.65       2       19.30             268-348
                
Sub Total            314.28    
                
        Madisound        
Part    Unit Price ($)    Quantity    Total Price ($)    Part Number
5uF Capacitor    0.75      4                 3.00                    n/a
.33mH Inductor    5.10      2             10.20                          n/a
.6mH Inductor    7.50      2               15.00                   n/a
1.0mH Inductor    9.60      2             19.20                       n/a
1.25mH Inductor    10.50      2           21.00                    n/a
27TDFC Tweeter    32.45      2             64.90                  n/a
                
Sub Total            133.30    
                
    Other            
4x8 MDF Sheet    20.00    1    20.00    n/a
Glue, etc.    10.00    n/a    10.00    n/a
                
Sub Total            30.00    
                
Total            477.58 

[ThomasW]

What size should the tweeter backing plates be?

The exact size isn't critical. This is a picture of one being glued in place.

"5uF Capacitor (C5,C6) $34.08 x4 $136.32"

Where can I get these? :W

Those are the AudioCap Theta. With the right playback equipment they sound very good... :T

[catacon]

For the Modula MTM's, what size does the hole for the port need to be (both on the back and on the brace)? I know it is a two inch port, but the Precision port looks like it has a rim. I figured 3 inches. Is that correct?

Thanks!

[PoorboyMike]

For the Modula MTM's, what size does the hole for the port need to be (both on the back and on the brace)? I know it is a two inch port, but the Precision port looks like it has a rim. I figured 3 inches. Is that correct?

Thanks!

I cut mine 4 1/8" and there isn't much wiggle room. Maybe 1/32 all the way around.

[Evil Twin]

The clearance hole in the center brace can be only 3", but the hole in the back panel should be as Poorboy Mike describes above- this is for a length where the flared portion will just be resting on the inner brace after it is all glued together with ABS cement.

[catacon]

OK, so the brace hole is 3" and the back panel hole is 4 1/8".

Thanks!

[ThomasW]

For the Modula MTM's, what size does the hole for the port need to be (both on the back and on the brace)? I know it is a two inch port, but the Precision port looks like it has a rim. I figured 3 inches. Is that correct?

Thanks!

The wise builder waits until they have the parts in hand before doing any cutting.

I've never used the PSP ports before but I have a pair here for the new WMTW. The end they tell you to do the cut-out for has a VERY narrow lip. The other end has a huge lip the OD of the flange is 5.5".

I seen no reason to dork around with the small end and the minimal clearance between the cutout and the edges of the flange. Although we haven't discussed it Jon obviously agrees with me since he's mounted his as I would. Big flange on the outside.





Little flange on the inside...



And before anyone asks no the flange doesn't have screw holes in it. So drill your own, using the marks on the back side of the flange to use as drill guides.

[JonMarsh]

The flange provides the option of tri-spaced or 90 degree spaced holes, if I recall correctly.

Thanks for linking the pics in, Thomas.

[JonMarsh]

What size should the tweeter backing plates be?

For reference, these were cut from 1" X 6" stock, which means they're actually 0.75" X 5.5", cut 6-7/8" long. Exact dimensions are not critical, as long as the baffle fits back into the enclosure.

[JonMarsh]

"5uF Capacitor (C5,C6) $34.08 x4 $136.32"

Where can I get these? :W

A good lower cost substitute can be found on this page:


Sonicaps


NOT the 600V version, unless you want to spend about the same, but the 4.7 uF 200V ($11.20), or the 5.0 uF 400V ($17.60).

The AudioCAP Theta are available from PE as well as Sonicraft. These "botique" caps are recommended for getting the best performance in systems with source components, amplification, and cables a cut above standard HT gear. May not be justified in all cases. Examples where it IS justified clearly are when using a good SACD player, CD DAC like a Benchmark DAC1, and with good separates for amplification. This isn't religion, just an option to get a bit more performance. The Sonicaps will get you 90% of the way there to what the AudioCAP Theta does, so it may be the smartest choice if you elect to go that route.

This probably sounds a bit over the top; Thomas was skeptical until we did a swap out in his family room Arvo Parts. The benefit compared with Solen is quite audible in my "small" home system, which uses an Ayre AX-7 Integrated amp, an Apple iMac, a Marantz SA-11, and custom Kimber 8TC cables; with substituting my Cardas Golden Reference speaker cables, it's a bigger benefit yet. Wish it weren't so, but that's how life is....

As always, YMMV, it's your money, yadda yadda yadda badda bing. :W

(I don't want to get a reputation as some kind of hard core tweak nut, you know). :B

~Jon

[JonMarsh]

Those resistors are very expensive, $3.50 a piece?

Mills resistors, available at Madisound and PE. I hate most resistors... these I hate less than others. :W

[ColoradoTom]

My cabinets were delivered about 20 mins ago, so it's time to make sawdust... :T

Stolen from a fellow woodworker.......

"It's wooddust - if you're making sawdust you're doing something wrong!!!"

ColoradoTom

[TacoD]

Mills resistors, available at Madisound and PE. I hate most resistors... these I hate less than others. :W

That explains why . In my experience component quality in xo-filters is indeed noticable in a setup which is a bit more revealing then a HT-receiver, however, first spend on the more important stuff (HQ enclosure and drivers).

My experience with sonicaps are limited, but I prefer the European boutique caps (e.g. Mundorf)

[catacon]

Is the bracing centered front to back?

About the MTM Center:
What schematic should I use; the one is post #1 or the one in post #30?

Thanks!

[JonMarsh]

Is the bracing centered front to back?

About the MTM Center:
What schematic should I use; the one is post #1 or the one in post #30?

Thanks!

The schematic in 30 was the last update. Has some additional contouring. This is for the CC two way design using the SS6000 tweeter and close driver spacing.

There is a three way CC in the same size cabinet being completed in the next week or so... if you haven't already bought components, you might want to hold off and see how that turns out. Cost will probably be similar, as the SS6000 is about $130, versus ~29.00 for the Vifa D26CN55 plus $33.65 for the Dayton RS52AN 2" dome midrange.

Thomas and I will be working on the first build in Denver next week.

[catacon]

I was thinking about waiting for the three way, but I haven't decided. How long will it take for the "final" crossover to be made? It seems like there are always a few updates before the final is reached.

[ThomasW]

Unless something very unexpected happens, the final crossover for the design that uses the Hi-Vi D6.8 woofers should be posted next week in the build thread. The crossover for the design using the RS180 woofers won't be far behind.

[catacon]

Since I will be using this speaker with Modula MTM and Modula MT both with RS180s, would it make more sense to wait for the RS180 version?

[catacon]

Well I got the MTM cabinets built. Now they get to sit and wait until I get enough for the crossover parts and drivers.

I'm kind of in a jam with building the WMTW center. I need to finish the cabinets this week because I am borrowing clamps from someone and they need them back by next week. I know the design isn't done yet, but does anyone know where the port (it is ported right?) will be positioned? Is it the same as the other speakers (centered top to bottom)? I don't have any hole saw big enough to cut the hole after I put the cabinet together, so i need to do it before I put it together.

Thanks!

[ThomasW]

Patience is a virtue.......at this point we can answer posted questions or build the speakers....

If the boxes are built there's little need for clamps.

The port location will be just like the Modula MTM/NatP.

The only cabinet woodworking difference is the bracing behind the mid/tweeter will have a hole cutout for the RS52.

[catacon]

Great, thanks!

[catacon]

I order the parts for my Modula MTM's, and they will be here on Thursday. I have a few questions:

1) What can I use for dampening material? Do I have to buy or special material?

2) I noticed that the tweeter backing plate blocks the terminals. Can I just drill a hole to get to them or cut part of the plate away to get to the terminal?

Thanks again for all your help!

[JonMarsh]

Drill holes through the backing plate to run the wires through and seal with hot glue (optional)

[catacon]

All right, I need a little help with my Modula MT crossovers. I finally got around to making them.

I wired everything up and ran a test pattern of sine waves starting at 3000hz going down in increments to 800hz. Now, the sound should only be coming from the tweeter above 1800hz, and then below 1800hz the sound should only be coming from the woofer, correct? Well, that's not the case. It seems that all frequencies play through both of the drivers all the time. I checked the wiring with the original schematic and another block diagram I have, and everything seems to be wired fine. Is ther something I'm missing?

I will post a diagram of my wiring in a little while.

Thanks!

[Dennis H]

The crossover isn't a brick wall. It gradually rolls off the drivers above and below Fc -- green and blue lines in the pic. If you're doing it by ear, try testing at much high and lower frequencies.

[catacon]

Thanks Dennis. I will try testing with higher and lower frequencies.

Here is a diagram of my wiring. Sorry about the unorthodox drawing, but it's the best I can do with Paint.

Thanks!