Thursday, January 11, 2007

DIY ProAc Response 2.5 Clone - Part 1

Tools, Material and Parts

In the last article, I gave a little background on my journey building a ProAc Response 2.5 loudspeaker project. I'm thinking of dividing the project into 4 articles:
In this article, I'll list all the tools, parts and material needed to build your own loudspeakers. Since this is a few years ago, the cost of material, parts and the stores I bought my items may have changed or may not be available.

Below is a list of online store I frequently visit for audio part supplies:

  • Tablesaw - You can use a circular saw, but you'll need a long straight edge.
  • Router and Router Bits - a 1/4 and 3/8 straight bit to trim veneer and to cut the circular holes. My router comes with a plunger, which is needed to route the bevels on the speaker holes.
  • The Jasper Model 400 - This is the jig I used to cut all the port and speaker holes.
  • Measuring Tape - Since the diagram measurements are all in metric, I suggest you pick a metric one. I bought this Stanley Metric/Fractional Tape one at Lowes.
  • Clamps - a minimum 4 clamps are need to glue the speakers together. The more the better. I bought a set of cheap clamps from Lowes for $20. Here is what the set looks like on Amazon. Here.
  • Orbital Sander - Use to sand flush imperfections when gluing the panels (a belt sander is probably better, but I don't have one) and for sanding the wood veneer.
  • Glue - Wood glue (Titebond). A spray adhesive to glue the Dampen Polly Fill. I used the 3M Supper 77.
  • Contact Cement - This is use to for veneering your speakers. I went with DAP contact cement (waterborne) and got good result.
  • Hot Glue Gun - This is to glue crossover parts onto a board.
  • Rolling Pin - I used my wife's baking tool. :)
Use this list as your reference as well.
  • Two 4' x 8' MDF board. I think you can get away with just one if you plan your cut well. I ended up using 2 because I made a mistake on one of the speaker panel. (~$25 per board)
  • 3" PVC pipe - This is for the port. You just need a pipe long enough to create two 6-inch long ports. I've a leftover PVC pipe from my past plumbing project.
  • Roofing Felt - For the 3-5mm bituminous felt damping.
  • Polly-fill - Damping foam lining.
  • 1 x Maple Wood Veneer (4' x 8' sheet). I ordered mine from here. $84 + S/H.
  • 2 x 18w/8535 Scan-Speak - I bought mine from Speaker City. You can get the shielded version if you are going to put these speakers near a CRT TV. $281.60
  • 2 x D2010/8513 Scan-Speak. $113
  • Solderless terminals for speaker. it looks something like this. I just went to my local Radio Shack and picked up a bag of these.
  • 12 AWG speaker wires. A 25-ft spool from Radioshack should be sufficient.
Crossover Parts
I built my crossover based on this diagram. Troels' modified crossover. I built it with the Optional Notch. I did not get all the parts with the exact specs listed in the diagram. I tried to get as close as possible. During my search on the web and reading DIY forums on people who have built speakers in the pas, I have concluded that most of these folks have good experience with Mills brand resistor. Getting Mills resistors from an online source to buy is a bit challenging. I ended up getting Dale 1.5-Ohms/5W and Dale 5.6-Ohm/5W from Surplus Sales of Nebraska. I just did a quick search on Google now and this place offer Mills resistors.
As for the 47-Ohm/5W resistor, I got them from here.

I think this will work as well, it's just rated with higher wattage.

I bought 10 or more resistors of each type just in case I decided build more clones for friends and family. All these parts sits on a square laminated floor board I have leftover from my past project.

Next article: Woodworking - Cutting and Gluing


Anonymous said...

If I may offer a suggestion, two of the inductors need to be reoriented so that the lines of force are 90 degrees to the other coils.

Damaged Tree said...

Thanks for the suggestion. Since I'm pretty new to the world electric/electronic, I've not sure I understand what you are saying..:)

What is the benefit if the force is oriented 90 degrees oppose to the other inductors? Is it to minimize interference? Just curious.

Byeong Seon said...

Nice job you have done! I am going to start my first DIY speaker project with Response 2.5. I am thinking to ask Home Depot to cut the MDF to the specs. They say they cut with $.25 per cut. But no circular holes :(. Do you think it is a good idea to ask them to cut to the spec? Also, did you buy two different thickness MDF (1" for front and back, 0.75" for sides)? Your input would be greatly appreciated. B.

Damaged Tree said...


I think if Home Depot folks can cut your MDF board to specs, I would let them do it. I only have them cut my mine in half so that it's more manageable to transport and cutting it at home. it was a free courtesy service from HD.

For the circles, I used a plunger router and a jig to cut circular holes. It's not as tough as you think. I did a practice run on a scrap board.

As for the thickness, I used 0.75" for all sides. I think if you used 1" for the front, you might have issue fitting the speaker drivers. You might have to flare out from the inside. (not sure if know what I meant here).

Anyway, just post any questions, I'll try to help if I can.

Byeong Seon said...

I am not sure what you mean by fitting driver problem if front is 1"... Also, can you attach your CO directly on the inside of back MDF behind the drivers (is spece issue here)? Can CO readily accessible in your design?
Again, thanks for your help.

Damaged Tree said...

I was thinking because it's a bit thicker (1" compare to 0.75"), the prongs on the drivers where you connect the speaker wires might be blocked. It's been 3 years, so this maybe not be an issue. I'm curious what your reason for a thicker front? If you want a more rigid box, maybe adding more bracing serves a better purpose, but it reduced the internal cabinet volume. You can increase the cabinet size to compensate this.

For the CO, mine is pretty much inaccessible. It's on the bottom of my speakers. I'm not sure if the CO will fit right behind driver, there is not much room there. The best way is probably have your CO outside your cabinet if you like it accessible or maybe something you can take out from the bottom of your speakers.

Byeong Seon said...

I just followed the cabinet link and the drawing says 1" front and back. I don't know whether this makes difference. I will go with all 0.75" this time. Thanks.

Byeong Seon said...

Hi, D.T.
I have one question regarding router tool. I am planning to buy one to cut the speaker holes and recess. there seems two type. Fixed base and plunge base. do you know whether this doesn't matter to accomplish to make a hole on 1" thick MDF and recess? Also, what kind and size of bits are suitable for this kink of job? thx.

Damaged Tree said...


Get the Plunger router. You need that to cut the recess. I used a 3/4" straight bit to cut the recess and a 1/4" straight bit to cut through the holes. Remember to cut the recess first before you cut through.

As for the depth of the recess, the diagram calls for 4mm and 5mm in depth. Depending on what kind of finishes you plan for your speakers, you should account the difference. For example if you plan to veneer your speakers with a 1mm thick veneer, you should cut your recess depth 1mm less (3mm and 4mm). That way, your speaker drivers will be flush with your cabinet once they are installed.

Anonymous said...

I notice you use 3.3uf Caps instead of 3.4uf or 3.3uf with 0.1uf in pararllel. Also using a 0.27mH inductor instead of 0.25.

Does this make any audiable difference then to a model built to the specific XO scematic?


Damaged Tree said...


Yes, I used slightly different specs because I could not get the exact number specified in the clone docs. I can't tell you the audio difference because I have nothing to compare them to. It sound awesome regardless. I still use the clone for music listening. I recently upgrade my front end to a NAD C352. It really make them sing.

Anonymous said...

Ok great thanks for your reply. Yes I used to have a C352, great little amp, but since then upgraded to a MF A5 :D

The CAD drawing of the cabinets has confused me slightly though in regards to the front and botton and bracing.. it sais the length is 189mm, and 25mm thick, but what is the width?? as 189mm I would assume will leave a gap and 205mm wont fit cos the sides are 205mm?

Many Thanks.

Damaged Tree said...

Nice amp, a little too pricey for me. Maybe I can pick up a used one in a few years. Anyway, this can be confusing because the CAD drawing calls for 2 different board thickness. 25mm for and 18mm. Since I used 18mm (3/4 inch board) all the way around. I adjust the measurement accordingly. If I do it again, I'll build the front to be 25mm.

255 - 25 - 25 = 205
225 - 18 - 18 = 189

Anonymous said...

Thanks for your help. J.

Albert M said...

Clone site has moved to: