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MFW-15 Project Advice Needed - Page 3

post #61 of 100
Quote:
Originally Posted by coctostan View Post

It might not be worth it at that price point. It is a nice driver but nothing special. It is just the value at the current price is off the charts.

I agree. But it might be cheaper, I could find out if needed. If it was closer to $100-$110 and pretty much like the $160 DVC, then it might not be bad. It would depend on how many were initially ordered. If it makes sense, I don't mind doing it when the time comes. But no need to worry about that right now.
post #62 of 100
How much different is this driver than the Quattro PE used to sell? They routinely were on sale new for 79.

I also hear they are coming back........
post #63 of 100
Quote:
Originally Posted by NicksHitachi View Post

How much different is this driver than the Quattro PE used to sell? They routinely were on sale new for 79.

I also hear they are coming back........

I think the Quattro had under 10mm of X-Max and a higher Fs.
post #64 of 100
Quote:
Originally Posted by Erich H View Post

I think the Quattro had under 10mm of X-Max and a higher Fs.

I don't remember exactly, I got the spec printout at work though. Seems like your right the Fs was something Like 20ish?

The motor structure was strikinglly similar to the MFW though....

Quote:
Originally Posted by NicksHitachi View Post

How much different is this driver than the Quattro PE used to sell?.

Apparently Mucho.
post #65 of 100
Here are some Quatro 15 specs I measured a while back. Compared to the MFW, the Quatro has a lower Vas, higher Qes, higher Fs, higher Mms, and a bit more BL. Not at all a bad driver.

Vas test completed: Sun Jan 13 20:22:40 2008
Vas drive current 2391.85 uA
Shunts: Not Used
;------------------------------------------------------------------
Re = 3.2701 ohms
Fs = 24.0619 Hz
Zmax = 103.9243 ohms
Qes = 0.4369
Qms = 13.4475
Qts = 0.4231
Le = 3.7540 mH (at 1 kHz)
Diam = 325.0000 mm ( 12.7953 in )
Sd =82957.6775 mm^2(128.5847 in^2)
Vas = 146.4798 L ( 5.1729 ft^3)
BL = 18.1777 N/A
Mms = 291.9981 g
Cms = 149.8304 uM/N
Kms = 6674.2124 N/M
Rms = 3.2828 R mechanical
Efficiency = 0.4389 %
Sensitivity= 88.4414 dB @1W/1m
Sensitivity= 92.3267 dB @2.83Vrms/1m
post #66 of 100
Thread Starter 
Well I finished up my project. I went ahead with the 3cuft design, though nothing fancy with the enclosures (which was good, this being my first time working on a cabinet this large). I definitely learned to cut the pieces larger than needed so I could let the router do the work, although a little too late. In spite of everything I think they came out nicely, and even if they're not the prettiest, they still sound pretty impressive, especially in my small space.

I won't have a chance to do any finishing (in terms of stain/paint) for a while, but I've started to consider my options. I'm thinking of having a painted front baffle, and staining the rest. For that kind of finish, which do you think I should start with? Should I paint first, then tape it off to stain, or stain and tape that off to paint?

I'll post up some REW plots when I get a chance. Hopefully it'll look alright, although if it doesn't there's not much I can do outside of EQ since they're placed in the only possible positions due to space constraints.

Anyway, below are a few pictures of the subs as they stand, and the kind of finish I'd like to go for.
LL
LL
LL
LL
post #67 of 100
Those are purrrty. Looks great!
post #68 of 100
Thread Starter 
Thanks. I've got a more detailed build log in my blog if anyone's interested in seeing all the mistakes I made, haha.

I also have one more question. Do you think spikes would be worthwhile? The subs are just sitting flat on the floor right now. I'm wondering if it would make a difference in the sound.
post #69 of 100
Get an auralex gramma or subdued instead of the spikes. It will give you better sound and give the subs a floating look
post #70 of 100
Thread Starter 


Here's the REW graph for these subs. The purple was taken after I stuffed them with some polyfill from Walmart pillows, and the blue one was taken without polyfill.

Unfortunately I don't have much flexibility with placement (as in, they have to stay where they are now), and this won't be my permanent residence, so room treatments wouldn't be worth it for now. I'm guessing this means that EQ is the only way to go to try to flatten this out?

Any help would be appreciated.
LL
post #71 of 100
Oh dance music is your friend!
post #72 of 100
Thread Starter 
I just finished up the final coat today. I decided to stain the whole cabinet to keep things simple, instead of painting the front baffle black. The original rationale for the paint was because of some of my screwups during construction that required lots of of wood filler to remedy. I think it turned out pretty well in spite of the fact that the filler is kind of hard to miss.

I ended up finishing these with 3 coats of wipe on poly. I was planning on going up to 8-9, but it went on very nicely, and I reached the finish I was going for with just a single can (which was also nice).

Here's the result before final assembly. I'll be taking them outside for some beauty shots (at least I think they're beautiful ) in the next couple of days.

Thanks to everyone for all the help!


LL
post #73 of 100
Quote:
Originally Posted by Scott C. View Post

I just finished up the final coat today. I decided to stain the whole cabinet to keep things simple, instead of painting the front baffle black. The original rationale for the paint was because of some of my screwups during construction that required lots of of wood filler to remedy. I think it turned out pretty well in spite of the fact that the filler is kind of hard to miss.

I ended up finishing these with 3 coats of wipe on poly. I was planning on going up to 8-9, but it went on very nicely, and I reached the finish I was going for with just a single can (which was also nice).

Here's the result before final assembly. I'll be taking them outside for some beauty shots (at least I think they're beautiful ) in the next couple of days.

Thanks to everyone for all the help!


Very nice, can't wait to see them with the drivers in.
post #74 of 100
Thread Starter 
I dropped the drivers in and hooked them up today. I noticed quite a difference from when they were set up previously. It may just be me, but I think it might have to do with the bracing. Originally I only had side to side bracing, since I knew I would be opening them up again, but when I went to do the staining I added some top to bottom bracing. Before, I could feel the subwoofers quite a bit more, but now I don't feel it as much, and it seems to sound a bit cleaner. Maybe the bottom was flexing, causing more vibrations? Seems unlikely considering how rock solid these things felt even before the bracing. Would that be within the realm of possibility?



I had my BIC H100 hooked up while these were out of commission, so before I hooked up the new guys again, I took the opportunity to measure both sets from the same position (and tried to get the same level). So here are the results. The MFW-15's look pretty much the same as before, but the comparison was interesting.


LL
LL
post #75 of 100
nice work there.

looks like you might be getting pressure vessel gain kicking in around 30hz.
post #76 of 100
Quote:
Originally Posted by Scott C. View Post

I dropped the drivers in and hooked them up today. I noticed quite a difference from when they were set up previously. It may just be me, but I think it might have to do with the bracing. Originally I only had side to side bracing, since I knew I would be opening them up again, but when I went to do the staining I added some top to bottom bracing. Before, I could feel the subwoofers quite a bit more, but now I don't feel it as much, and it seems to sound a bit cleaner. Maybe the bottom was flexing, causing more vibrations? Seems unlikely considering how rock solid these things felt even before the bracing. Would that be within the realm of possibility?



I had my BIC H100 hooked up while these were out of commission, so before I hooked up the new guys again, I took the opportunity to measure both sets from the same position (and tried to get the same level). So here are the results. The MFW-15's look pretty much the same as before, but the comparison was interesting.


Quote:
Originally Posted by LTD02 View Post

nice work there.

looks like you might be getting pressure vessel gain kicking in around 30hz.

Yup, tame 50hz and you should be flat.

Hows it look down to 10?
post #77 of 100
Quote:
Originally Posted by Scott C. View Post

Before, I could feel the subwoofers quite a bit more, but now I don't feel it as much, and it seems to sound a bit cleaner. Maybe the bottom was flexing, causing more vibrations? Seems unlikely considering how rock solid these things felt even before the bracing. Would that be within the realm of possibility?

A 20"X3/4" panel unbraced will resonate like crazy. If the sub was laying flat(no feet) some of that may have translated to the floor I suppose. How much polyfill are you using? 1lb per cubic foot?
post #78 of 100
Thread Starter 
Quote:
Originally Posted by NicksHitachi View Post

A 20"X3/4" panel unbraced will resonate like crazy. If the sub was laying flat(no feet) some of that may have translated to the floor I suppose. How much polyfill are you using? 1lb per cubic foot?

Yeah, they were laying flat. The polyfill is just some walmart pillows. One per cabinet. I'm not sure how much was in each one, but I doubt it was 3lbs. Would you recommend more?
post #79 of 100
Quote:
Originally Posted by Scott C. View Post

Yeah, they were laying flat. The polyfill is just some walmart pillows. One per cabinet. I'm not sure how much was in each one, but I doubt it was 3lbs. Would you recommend more?


The rate of return is diminished after about 1lb per cubic foot. Walmart sells the polyfill in the textile fabric department 3lb bag perfect for each sub for <$9 each. What size pillow? You prob could have gotten away cheaper with the straight poly, but you know what they say about hindsight.

Up to about 3lbs you should see noticeable improvement in the bottom end response as the stuffing changes the Q. This will also change the character of the subs sound and you might like the sound with less stuffing, its up to you.

Again all theoretical speak you might add it and not notice anything. Maybe some of the others who have finished their MFW builds can testify on the real world benefits for ya.
post #80 of 100
Thread Starter 
Quote:
Originally Posted by NicksHitachi View Post

The rate of return is diminished after about 1lb per cubic foot. Walmart sells the polyfill in the textile fabric department 3lb bag perfect for each sub for <$9 each. What size pillow? You prob could have gotten away cheaper with the straight poly, but you know what they say about hindsight.

Up to about 3lbs you should see noticeable improvement in the bottom end response as the stuffing changes the Q. This will also change the character of the subs sound and you might like the sound with less stuffing, its up to you.

Again all theoretical speak you might add it and not notice anything. Maybe some of the others who have finished their MFW builds can testify on the real world benefits for ya.

Thanks for the info, I didn't think the polyfill would have that big an effect. I thought it was just to mask mechanical noise. Good to know. I'll have to go check on those polyfill bags at a different walmart. They just didn't have any at the one I went to. The pillows were "Standard" size.
post #81 of 100
Michaels arts and crafts has 20oz bags for $5 as well. I used two bags per 3cf enclosure. I use spray adhesive to make sure I get polyfil on all exposed wood inside even though I know not necessary.
post #82 of 100
so...what became of the dual and quad/opposed MFWs and the modified SA-1000 amp? I know they ran out of drivers long ago. I've got three sitting in boxes in the basement and am just now getting around to making a project out of them. Was the SA1000 a success or did it fizzle due to lack of demand? Not much action on the related forum on Seaton Sound...
post #83 of 100
Good question. Not sure what happend to the SA1000, but I have four MFW's that I still need to build enclosures for. Once done, I'll make a thread and you better too!
post #84 of 100
Last i heard they had amps ready to go, but they needed to be moving turbo kits to free up drivers in a significant number.

I think their V2 turbo kits are now shipping in frequent surges, or may be in stock by now.

People are asking waaay too much for their used drivers over there though IMO. $100 plus shipping? Please who wants YOUR used driver for $120 when a NEW DVC PE 15 goes $99-129 shipped?

Anyhow hopefully more turbo kits will ship, freeing up more drivers, and folks come to a more realistic expectation on used driver pricing. That kit is a good bang for the buck DIY option IMO.
post #85 of 100
I'll sell mine for $1000 each, new! Just kidding...

I think I'll start with an F-20 and then maybe from there build a dual opposed. The cool thing about the F-20 is I can power it pretty well with an old 80 watt receiver at least for starters (with some DSP up front).
post #86 of 100
Thread Starter 
Dredging this up for a little advice. Eventually I'd like to get a MiniDSP to play around with EQ, and to add an LT for these guys (2 MFW-15 in 3cuft boxes) if possible. Will these drivers be able to handle an LT? I know the power rating and excursion for the MFW-15 aren't the greatest, but my understanding is that the small volume of the box should keep the excursion in check at least in terms of not damaging the driver, right?
post #87 of 100
it doesn't really matter what kind of eq that you employ, you still don't want the drivers shooting into damage land. iirc, that driver is fine into the upper teens or so for excursion, so that would mean about a 500 watt limit in a 3 cubic foot sealed enclosure.
post #88 of 100
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

it doesn't really matter what kind of eq that you employ, you still don't want the drivers shooting into damage land. iirc, that driver is fine into the upper teens or so for excursion, so that would mean about a 500 watt limit in a 3 cubic foot sealed enclosure.

Very true, haha. Thanks! And that's good to hear. Can the same be said for the Dayton DVC? Down the road (probably a long way down) I'd like to build up a couple more, and with the MFW-15s dried up, that looks like the best option.
post #89 of 100
"Can the same be said for the Dayton DVC?"

yeah...
post #90 of 100
I have 8 MFW-15's that I purchased from Erich H in July 2011 that I still have not done anything with. I'm thinking a different route maybe. They are in the original boxes and Erich put them in another box, however I don't have those boxes anymore. I'd be willing to part with all 8 if there was interest. I'd want 77 bucks for each driver plus shipping but, would prefer pick up.
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