Mfw-15 clone project

nottaway · « **on:** 23 Nov 2010, 12:20 am »

Ok so I starte a MFW-15 clone project.....

With all the spare parts flying around and what I already have it should be a stout performer for money invested.....

Here's the post I'll keep it updated

http://techtalk.parts-express.com/showthread.php?t=221293

Danny Richie · « **Reply #1 on:** 23 Nov 2010, 12:47 am »

My 2 cents: Add a lot more bracing than the original.

nottaway · « **Reply #2 on:** 23 Nov 2010, 11:58 am »

How about lining the inside with acoustic foam? I have some laying around...... The original has a piece of insulation thrown to the back, what type of improvements could be made there? OC 703 Maybe?

Danny Richie · « **Reply #3 on:** 23 Nov 2010, 01:36 pm »

If it were mine, I'd line it with No Rez.

dvenardos · « **Reply #4 on:** 23 Nov 2010, 07:23 pm »

If you need cheap make your damping layer with vinyl floor tiles.
None of the insulation you could use would do anything down at subwoofer frequencies.

nottaway · « **Reply #5 on:** 23 Nov 2010, 07:55 pm »

Quote from: dvenardos on 23 Nov 2010, 07:23 pm

If you need cheap make your damping layer with vinyl floor tiles.
None of the insulation you could use would do anything down at subwoofer frequencies.

Vinyl floor tiles?

Got a link?

aharami · « **Reply #6 on:** 23 Nov 2010, 08:38 pm »

Quote from: nottaway on 23 Nov 2010, 07:55 pm

Vinyl floor tiles?

Got a link?

Danny also mentioned to me over the phone that vinyl tiles available at HD or Lowes can make cheap dampening layer (for my surrounds. Im using No-Rez for my mains). But I wonder which tiles exactly

Danny Richie · « **Reply #7 on:** 23 Nov 2010, 08:45 pm »

http://www.homedepot.com/Flooring-Vinyl-Resilient-Flooring-Vinyl-Tile/h_d1/N-5yc1vZ1xhcZaq27Z1z11ijz/R-100183098/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

nottaway · « **Reply #8 on:** 24 Nov 2010, 05:26 pm »

Quote from: Danny on 23 Nov 2010, 12:47 am

My 2 cents: Add a lot more bracing than the original.

What type of bracing and where? VCt tile huh? Neverheard that one....

dvenardos · « **Reply #9 on:** 24 Nov 2010, 05:32 pm »

Might want to check out this thread.
http://www.audiocircle.com/index.php?topic=86324.0

Quote from: nottaway on 24 Nov 2010, 05:26 pm

VCt tile huh? Neverheard that one....

nottaway · « **Reply #10 on:** 24 Nov 2010, 07:00 pm »

Ok so that pretty much covers the dampening.

Anyone suggest which areas need better bracing? I was thinking of adding another cross brace to reach the baffle since it's not braced at all. Would you guys do corner bracing? If so what kind? I don't want to get crazy since I'm trying to stay close to original volume.

Danny Richie · « **Reply #11 on:** 24 Nov 2010, 07:36 pm »

What you need to focus on when bracing is keeping the panel size small. So there is no need to brace the corners. The corners are the least resonant area. I typically like a brace at least every 3 inches or so on a sub especially if it just uses 3/4" MDF.

See some of the plans on the GR Research site for ideas.

nottaway · « **Reply #12 on:** 25 Nov 2010, 07:32 pm »

Thought I would update all cuts done dimensions came out perfect. Need to seal glue up add some bracing and sound deadening and finish

Trace it out...

All cut and loose fit...

Danny Richie · « **Reply #13 on:** 25 Nov 2010, 07:53 pm »

Yeah, those panels are way to huge to not be braced. They'll resonant like crazy. I'd add bracing between the outer wall and the panels that make up the slotted port all the way around and in at least three rows.

The braces will take up some space in the port and tune it lower. So you might also have to shorten it some if it lowers it too much.

I'd also line all of the port with Dynamat or something similar to further control any resonances of each panel.

You might want to check out these pics in this thread: ...audiocircle.com/index.php?topic=53675.0 The pics might give you some ideas on how to run the braces.

nottaway · « **Reply #14 on:** 25 Nov 2010, 08:27 pm »

I Calculated the tuning to be about 19hz and from that I calculated the enclosure volume to be about ******edit***** 3.0 cubed. I don't know how to know how to adjust the port based on how much I add inside the port? Would a lower tune be bad? The fs on this driver is about 15 right? I should be able to go a little lower without problems right?

The port was about 1 1/2 x 16 3/4 x 44ish....

Danny Richie · « **Reply #15 on:** 25 Nov 2010, 09:12 pm »

That box is a whole lot bigger than that. And in the original design I think there is a large hole in that brace right behind the woofer.

sch · « **Reply #16 on:** 25 Nov 2010, 11:37 pm »

I'll try to find some pics of the bracing to post. What I can confirm is Danny is right about the hole, there must be one.
Santiago

nottaway · « **Reply #17 on:** 26 Nov 2010, 12:56 am »

Ok so i was posting while out and after measuring I must have had a brain fart...... Actual volume is close to 3ft cubed not subtracting for the driver. The port is 1 1/2 x 16 3/4 x 44ish.

Yeah I cut the holes in the brace after I took the picture. I'm still unsure how to adjust the port for the added bracing which needs to be added to the port.
Do I calculate the volume added and subtract that from total volume of port?

Danny Richie · « **Reply #18 on:** 26 Nov 2010, 03:38 pm »

Actually you might wind up with a wash. Meaning that as you take up air space in the box with bracing then the port needs to get longer to maintain the same tuning. However, as you add some bracing inside the port that decreases the diameter which in turn tunes it lower.

nottaway · « **Reply #19 on:** 27 Nov 2010, 01:03 am »

Ok so I took the advice of sound deadening and bracing. I added just a tad more bracing to the port volume than I did to the cabinet volume which I think will be accounted for in the decrease volume due to the sound deadening. Ok so here's what I ended up with....

Port to back wall bracing..... I only went with two braces which puts panel size right at 4.5"

Sound deadening added.... After working with the VCT in this way I can see how it would help with resonances

Full frontal through driver hole.....

Remember only half the port assembly has been installed. So all thats left is installing the rest of the port which is already cut and pre-assembled and cut and install the bottom/Side. I'll also have a little work cutting the holes for amp controller wires and driver lead and cutting in the amp/controller cutouts.