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Lilmike's LilWrecker - Page 9

post #241 of 521
I'm using the Alpine. I took some measurements and sent them to Lilmike. He sent me this comparison back.


image by chilort, on Flickr

The green line is the original LilWrecker and the red line is the one I built. So the Alpine works and I spent more on wood than I did on the driver!

Lilmke then made me an EQ file for my miniDSP.
post #242 of 521
I will be keeping an eye on the barn the whole time. no straw on the floor and no smoking inside at all. I also will be living in it. I'm thinking of doing just one for now due to the price of wood. I'm hoping it fills in that large of a room.
post #243 of 521
How is everyone cutting all the plywood for this design? I assume a table saw would be the best way, but what is the next best way to cut it?
post #244 of 521
Thread Starter 
I use a tracksaw.

I have a great tablesaw, since I got the tracksaw setup a few years ago, the table saw gets used as a table.

While the tracksaw system isn't perfect, I much prefer moving the saw vs moving the wood, and I really like the idea of both hands on the saw.

Before I bought the tracksaw, I used a pair of shop-made circular saw guides. They worked well, but the tracksaw is far superior.

Edit - fixed link.
Edited by lilmike - 8/25/13 at 2:30pm
post #245 of 521
Quote:
Originally Posted by chilort View Post

I'm using the Alpine. I took some measurements and sent them to Lilmike. He sent me this comparison back.


image by chilort, on Flickr

The green line is the original LilWrecker and the red line is the one I built. So the Alpine works and I spent more on wood than I did on the driver!

Lilmke then made me an EQ file for my miniDSP.

Can you share the EQ ? Have a minidsp and I do want. Thanks!
post #246 of 521
I would recommend taking a measurement of the one you've built at the mouth and then post the response here for advice. I really think you need to setup your EQ exactly for your needs.

Now, if you are looking for a "safety EQ" then once I got mine running I had a 24dB/octave high pass at 14 HZ and a 48dB/octave low pass at 200Hz. This should keep it from clanking.
post #247 of 521
Thread Starter 
I didn't do anything special.

I used REW to auto-EQ the response to within 3 dB of flat, with cuts only, then I added a proper lowpass and highpass.

A couple of tweaks, and chilort measured this:



Without a measurement of your sub, there is really no point in using his EQ file.

Seriously - it is super easy to do with REW and a MiniDSP.

That reminds me - I need to re-EQ mine one of these days.
post #248 of 521
Quote:
Originally Posted by chilort View Post

I'm using the Alpine. I took some measurements and sent them to Lilmike. He sent me this comparison back.


image by chilort, on Flickr

The green line is the original LilWrecker and the red line is the one I built. So the Alpine works and I spent more on wood than I did on the driver!

Lilmke then made me an EQ file for my miniDSP.

So the comparison is without EQ? Looks like perfect driver is that's the case!
post #249 of 521
Thread Starter 
That is a raw response measurement, taken in the horn's mouth (not 1M groundplane like the original, but more than close enough for comparison's sake)

By the way - the Alpine is currently about $120 shipped.
post #250 of 521
Do you think this would be a good driver for the Lilwrecker?


Fs 15.7Hz
Qms 3.5
Qes .334
Qts .305
Vas 300.6L
Re 3.2ohms (coils in series)
Znom 4ohms (coils in series)
Xmax 27mm
Sd 748cm^2
Mms 269g
Vd 4.04L
RMS 800w
Le 2.4mH

It's similar to the Dayton DVC385-88/Tempest clone only more Xmas. It's a XBL^2 design by Dan Wiggins. I have 2 laying around doing nothing. Maybe they could find a new home. smile.gif I'm considering a BFM THT, but this design looks to go much lower and that's what I'm really after. SPL is just a bonus I guess.

Oh, and I have an original Adire Tempest sitting around too. LOL
post #251 of 521
Thread Starter 
Quote:
Originally Posted by Michael Mitten View Post

Do you think this would be a good driver for the Lilwrecker?


Fs 15.7Hz
Qms 3.5
Qes .334
Qts .305
Vas 300.6L
Re 3.2ohms (coils in series)
Znom 4ohms (coils in series)
Xmax 27mm
Sd 748cm^2
Mms 269g
Vd 4.04L
RMS 800w
Le 2.4mH

It's similar to the Dayton DVC385-88/Tempest clone only more Xmas. It's a XBL^2 design by Dan Wiggins. I have 2 laying around doing nothing. Maybe they could find a new home. smile.gif I'm considering a BFM THT, but this design looks to go much lower and that's what I'm really after. SPL is just a bonus I guess.

Oh, and I have an original Adire Tempest sitting around too. LOL

Those drivers should work fine in this cabinet.
post #252 of 521
Are there plans for this that someone can post? I have the cut sheets. Now I need the layout. I would greatly appreciate it!!
post #253 of 521
Thread Starter 
Everything I have shared on this one as far as plans is attached to post #1 of this thread. No one has written up any actual instructions as it is a pretty simple build. Start with the baffle, then build it from the inside-out, bracing it as you go.
post #254 of 521
I like that you can access the drivers without an access panel. If only you had this sub designed earlier. That said, I will never complain about my four F20s...as long as I don't blow a driver (which I never ever will because they will go WAY louder than anyone in the room can withstand). Cheers to lilmike...the man's man when it comes to DIY subs!
post #255 of 521
Quote:
Originally Posted by lilmike View Post

Everything I have shared on this one as far as plans is attached to post #1 of this thread. No one has written up any actual instructions as it is a pretty simple build. Start with the baffle, then build it from the inside-out, bracing it as you go.
OK, I will give it a go. Still searching for decent birch. Lots of import crap around here.
post #256 of 521
Quote:
Originally Posted by Michael Mitten View Post

OK, I will give it a go. Still searching for decent birch. Lots of import crap around here.

I used Arauco. I had to call Arauco though to even get started. They gave me phone numbers for wholesalers in my area, but the wholesalers don't sell to the public. The wholesalers did give me local contacts and I finally found the stuff. At less than $40 a sheet, I really don't know if you can beat it.
post #257 of 521
Just curious for all those that screw both sides of panels:

How do you get everything to line up so that your screws are going into ply?

I tend to screw one side of my panels in and then just use adhesive on the other side of the panel. I like the reassurance of knowing they are being held in securely with screws but am more afraid of everything lining up correctly. So for now I will just stick with PL.
post #258 of 521
Quote:
Originally Posted by chrapladm View Post

Just curious for all those that screw both sides of panels:

How do you get everything to line up so that your screws are going into ply?

I tend to screw one side of my panels in and then just use adhesive on the other side of the panel. I like the reassurance of knowing they are being held in securely with screws but am more afraid of everything lining up correctly. So for now I will just stick with PL.

This may be hard to explain in text...

I first map out the internal braces on one of the two side panels, I then stack and clamp these two side panels, with the "map" on top, and predrill the pilot holes. If your cuts and boards are true, your screws should catch wood the majority of the time.

If not, lots of PL doesn't hurt.
post #259 of 521
I will have to look at ideas and see what I can manage. If not PL will have to do. I will be making a few more MW soon so we'll see how I go.
post #260 of 521
Thread Starter 
Quote:
Originally Posted by Stumbo View Post

This may be hard to explain in text...

I first map out the internal braces on one of the two side panels, I then stack and clamp these two side panels, with the "map" on top, and predrill the pilot holes. If your cuts and boards are true, your screws should catch wood the majority of the time.

If not, lots of PL doesn't hurt.

This is exactly how I do it. It's also the approach detailed in the instructions for the Micro.
post #261 of 521
Mike did you have the instructions already made or are these future instructions?

And if these are made already can you send them to my email?

If not no worries. I need to go get some 19mm ply soon so I can slowly start building a few TH soon. (MW and other)
post #262 of 521
Quote:
Originally Posted by lilmike View Post

1W, 10W, 100W, 400W, and amp limits (iNuke 3000, bridged into 8 ohms), measured at 1M groundplane.


how do you get these wattage measurements, Mike?
post #263 of 521
Thread Starter 
Quote:
Originally Posted by Simonpink View Post

how do you get these wattage measurements, Mike?

The wattage I mention is what would be applied into the nominal driver impedance.

I measure voltage applied to a known resistance, then it is just a math problem.

Watts = Voltage^2/Resistance

I have some 4-ohm load resistors that will handle ~150 watts each, so when I wire them into an 8-ohm load, I can directly measure drive voltage up to ~50 volts before the resistors get overloaded.

I've measured my test gear at 1, 10, and 100 watts, and found that adding 10 dB of drive in REW does result in the expected voltage increase. As a result - during a typical test sequence, I set the 1-watt level accurately, then just step up from there.

For an 8-ohm driver, I set the drive level to 2.83 volts measured with a 60 Hz sine wave into an 8-ohm resistance, with the REW signal generator at -30 dB. I swap the resistor for the speaker I'm testing, then set the mic at a meter and run my first sweep. This would be a 1-w 1-m sweep. Depending on what I'm testing, I either step by 3 dB, 5 dB or 10 dB increments in REW drive level, and run the next sweep. I have occasionally checked voltage at the 10 W and 100 W sweeps to be sure things are working right.
post #264 of 521
Quote:
Originally Posted by lilmike View Post

I have some 4-ohm load resistors that will handle ~150 watts each, so when I wire them into an 8-ohm load, I can directly measure drive voltage up to ~50 volts before the resistors get overloaded.

I've measured my test gear at 1, 10, and 100 watts, and found that adding 10 dB of drive in REW does result in the expected voltage increase. As a result - during a typical test sequence, I set the 1-watt level accurately, then just step up from there.

So you use the load resistors to measure an accurate voltage reading with a multimeter?
post #265 of 521
Thread Starter 
Quote:
Originally Posted by Simonpink View Post

So you use the load resistors to measure an accurate voltage reading with a multimeter?

Exactly - I wire the resistor in place of the speaker, then set (or measure) the amp voltage delivered to that load.
post #266 of 521
did you buy the dummy resistor or make it yourself?
post #267 of 521
Thread Starter 
It is way easier to buy them. I got mine at MPJA.com, cost me a couple bucks each.

http://www.mpja.com/4-Ohm-120W-Power-Resistor/productinfo/17787%20RS/

Guess I got mine on sale....
post #268 of 521
I had to make my own. I need to have testing completed by next week for a uni project so I couldn't wait for shipping to Australia.
This one will do the job. http://sound.westhost.com/project124.htm



You're right, though. Way easier to buy one.
post #269 of 521
i bet those are some cool steel bikes you have in your assembly room
post #270 of 521


8 sheets of ply ripped and ready for a pair of SI HT15s smile.gif
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