Lilmike’s DIY Impedance Measurement Jig - AVS Forum
Forum Jump: 
Reply
 
Thread Tools
post #1 of 52 Old 06-11-2011, 06:08 PM - Thread Starter
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,184
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 13 Post(s)
Liked: 80
DIY Impedance Measurement Jig

Thanks to REW V5, we can now measure impedance and Thiele-Small parameters. It takes a little extra work to make a measurement jig, but this is not at all expensive, it is cheaper and easier to build than my DIY mic solution.

For clarification - I did not invent this. I am not claiming I did, I'm trying to show others how to make and use one.

The basic circuit is from the REW help file, tuxedocivic uses a similar jig with LIMPS/ARTA. I added the calibration switch, as well as created this howto.

All I am doing is presenting how I have done something to show others the way. The general circuit diagram for this is presented in the REW manual, as well as other places on the web.

As far as I know, however, no one has put one together and showed others how to use it with a UCA-202 and REW 5.0, as I will in this thread. The circuit is the simple part, using it to make the measurements is the important part.

Impedance measurements are a fundamental part of understanding what is going in in a loudspeaker. This is an inexpensive way to get there.

Unlike the mic project, I went ahead and built myself a nice one. I used a $3 project box, a single-pole single-throw switch, a 1-watt resistor, a few feet of interconnect wire, a pair of binding posts, and some connectors. For some removable test leads, I used a few feet of 18 AWG stranded wire, a pair of alligator clips, and a double banana plug. I’ll make another set with a speakon a bit later.

I use the Behringer UCA-202 soundcard for the bulk of my measurements now. It is definitely good enough, and more importantly for the impedance measurements, it has an adjustable headphone out. Also – I gotta admit – it is cheap enough that I won’t cry too much if I let the magic smoke out….I can pick up another one in less than 3 days for less than $30. Still – build this at your own risk. It works for me, and I’ve done my best to explain what I did as accurately as I can.

Anyhow – this how-to is based on that sound card.

Parts List:
1 Stereo 1/8” headphone plug
2 RCA Plugs (red and black)
6 feet of mono interconnect wire
(You could sacrifice a RCA to 1/8” stereo adapter here – it will work fine)
2 100 Ohm 1 Watt resistors
1 SPST Switch
1 small project box
1 dual binding post
1 dual banana plug
3 feet of red 18 Ga stranded wire
3 feet of black 18 Ga stranded wire
A pair of insulated alligator clips

Here is the schematic. It is pretty simple.


Assembly:

Mount the switch and binding posts to your project box, you can see how I did mine in the picture below. Your enclosure will probably be different than mine.



The Right Headphone out is our input signal, that is the ring connector. (#2 on J1) Connect ground to the shield (back) (#3 on J1), nothing gets connected to the tip. (Sorry for the lousy photo...)



Our sense signals are before and after the sense resistor, we’ll solder wires to each RCA (hot to the center, ground to the shield, to prepare these for connection. Here is an example:



Wire the two resistors in parallel to make your sense resistor. Measure the value of the sense resistor as accurately as you can and write this number down, then solder the sense resistor to the red binding post, leaving yourself some of the resistor leads to work with.

Solder the hot lead from J1 (miniplug) and J2 (black RCA) to the source side of the sense resistor. I bent the resistor wire to give myself a little more area for the solder to stick.



Solder a small wire to the source side of the sense resistor, then solder another small wire to the test lead side of the sense resistor.

Here is a picture of the resistor (a single one) with the pigtail wires attached to each side.



Solder all of the ground wires together, then connect them to the black binding post.



Tuck it all into the box, solder the leads to the switch.

The switch is connected as follows:

Source side pigtail to one terminal.

Sense side pigtail and J3 hot to the other terminal.

The result should look something like this:



Solder the alligator clips to the test leads, then connect the test leads to the dual banana jack.

Button up the box, you're set to go.

Now, let's test it and make sure it is all connected correctly.

Using a decent voltmeter, measure the resistance from the red test lead to the black test lead. Cycle the switch both ways.

There should not be any continuity here - if there is, something is wrong. Figure it out before going any further.

Next, leave the red test lead connected, measure resistance to J1, J2, and J3

J1 (1/8" Miniplug)
Tip = No Continuity
Ring = 99 Ohms (my sense resistor value) or 0.10 ohms (switch in cal mode)
Shield = No Continuity

J2 (Black RCA)
Tip = 99 Ohms (my sense resistor value) or 0.10 ohms (switch in cal mode)
Shield = No Continuity

J3 (Red RCA)
Tip = 0.10 ohms (both switch positions)
Shield = No Continuity

If you don't get these results (save for the value of your sense resistor) figure out why.

Finally, switch from red to black on the test leads, then repeat the measurements

J1 (1/8" Miniplug)
Tip = No Continuity
Ring = No Continuity
Shield = 0.10 ohms

J2 (Black RCA)
Tip = No Continuity
Shield = 0.10 ohms

J3 (Red RCA)
Tip = No Continuity
Shield = 0.10 ohms

If you don't get these results, take a moment and figure out why before connecting it to your sound card.

Calibration and use are pretty easy, I'll cover that in my next post.
lilmike is offline  
Sponsored Links
Advertisement
 
post #2 of 52 Old 06-11-2011, 06:09 PM - Thread Starter
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,184
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 13 Post(s)
Liked: 80
How to use this is covered in the REW manual, I'll run through an example though.

Connect the headphone plug to the UCA, set the volume to just under maximum.

Connect the red RCA to the right line in, the black RCA to the left line in.

Select Measure, then select the Impedance option.



Enter 0 for the sense resistor, and switch the calibration switch on (shorting the resistor internally).



Make sure the test leads are not touching.

Select Measure, you'll get the impedance calibration.

Turn the calibration switch off, enter the exact value for your sense resistor, connect your speaker to the test leads, and press measure again.

Hey presto, an impedance sweep....

lilmike is offline  
post #3 of 52 Old 06-11-2011, 06:18 PM - Thread Starter
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,184
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 13 Post(s)
Liked: 80
Measuring Thiele-Small Parameters

Take your first free-air sweep. Make sure that the magnet vent (if present) is unobstructed. I like to orient the cone similarly to how it will be operating for this sweep.

All it takes is another sweep and a few additional bits of information to get decently accurate Thiele-Small parameters.

Add weight to the cone or use a sealed test box to alter the resonance of the driver. Added weight is a lot faster, and is accurate enough in my opinion.

So - add a known weight to the cone. I use pieces of lead and a bit of blue-tack or similar to hold things in place. This can tear paper cones, so you might consider an alternative. I have measured decent results with just setting the weight on the cone, but things will not be quite as accurate. The cone was facing upwards for the weighted measurement. The weights tend to fall off otherwise.



Press measure (assuming you've not changed anything from the post above)

Now that we have both sweeps, select Tools, Calculate Thiele-Small Parameters from the REW menu.



The following window will open.



Select your free-air (first measurement) and your secondary (weighted) measurements in the appropriate drop-down boxes.

Measure the cone diameter (I use the center of the surround). Enter this measurement by clicking the little calculator button on the left side of the data entry field.

Measure the DC resistance of the coil as accurately as you can. Enter this value.

Enter the amount of weight you added. For the final run, I used 22.9 grams.

Now, REW can calculate the Thiele-Small parameters of the driver.

.

REW may complain about the Re value being too high. Change the value per the instructions and recalculate.

This is the Exodus Anarchy (cause I had one sitting here and I did not want to go out to the shop and try to carry in a different driver while trying to walk on crutches....).

Let's compare the results...



Well within the ballpark, especially considering this particular driver was fresh out of the box with no break-in. I'd expect things to be within 10% across the board after using the driver a bit.
lilmike is offline  
post #4 of 52 Old 06-11-2011, 06:20 PM - Thread Starter
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,184
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 13 Post(s)
Liked: 80
Measuring cabinets is the same as if you are measuring a raw driver.

You can use the impedance measurement of your driver or drivers in a cabinet to determine the port tune, the horn resonances, or the resonance of your sealed cabinet. This can also help you look for leaks and build problems. It can also help tweak crossovers.

Here is the impedance sweep of one of my T-24s:



Note the multiple impedance peaks - this is typical of a horn.

Here is a ported MTM 2-way cabinet with a tune of about 55 Hz.



Note the two impedance peaks, as well as the tweeter resonance. The tune is the minima between the first two impedance peaks. Might be a bit too much polyfill in there too, that lower peak could be higher.

Here is a small tapped horn (my last remaining T-6 prototype - it warmed up before it met the wood stove...).



So, now that we've see what it can do, how accurate is it? Not at all bad, until you get to the lower frequencies.

Here is a comparison with my WT2.



Clearly - there is a bit of a difference below 30 Hz, the deviation gets pretty significant by 10 Hz. Admittedly - the REW sweep takes 10 seconds or less, the WT2 sweep takes a minute or so. While a similar approach, the WT2 uses a more accurate method of calculating impedance, and in this comparison, the WT2 yields much better data below 30 Hz.

The UCA-202 soundcard does roll off below 10 Hz, and there appears to be no way to load a soundcard calibration other than when you do the impedance calibration.

Can the REW approach be improved? Perhaps. Judging by the waveforms on the scope in REW, my signals are not clipped, so I can increase the input signal further. My output signal looks rather puny though.



Perhaps I could get away with a different-sized sense resistor?

I tried several different resistor values. The lower the better the response, to a point. The headphone out only has so much power available. Changing to 160 ohms increased the impedance measurement, not the right direction there. Changing from 160 ohms to 53 ohms dropped the measured impedance at 10 Hz by 2 ohms, but it was still double the actual number. At 20 Hz, the difference was 1.3 ohms, but the value was still more than it should have been. Dropping down to 31 ohms, the measured impedance dropped another 0.6 ohms, but the value at the peak also fell by 5 ohms. Looks like, at least for the very low frequencies and low impedances, we're limited by the hardware.

I settled on 53 ohms for mine, but 50 would work fine too - just add another 100-ohm resistor in parallel with R1. Fortunately, Radio Shack sells them in packages of two. The schematic and instructions have been updated to reflect this revision. Scope output still indicates a nice sinusoidal waveform, so I did not break anything with this change.

I also determined that my test leads have a resistance of 0.11 ohms, that value is entered in the Rleads box next to the Rsense value in the measurement window.

I think this is about as good as one can hope to get with this approach. For sweeps above 20 Hz, I am pretty sure this will work fine. For calculating Thiele-Small parameters, this approach is far better than trusting manufacturer-supplied specs in most cases. Larger drivers may be more difficult to measure accurately. Also - ambient noise will mess with the results. Multiple sweeps and averaging might be a good idea.

I'll definitely stick with my WT2 for the stuff that matters. For quick checks? This works great.

Hopefully this has opened the door for others to measure impedance of their projects.
lilmike is offline  
post #5 of 52 Old 06-11-2011, 07:07 PM
AVS Special Member
 
tuxedocivic's Avatar
 
Join Date: Feb 2010
Location: Ladysmith, BC
Posts: 4,532
Mentioned: 4 Post(s)
Tagged: 1 Thread(s)
Quoted: 236 Post(s)
Liked: 497
I appreciate you posting this, and the DIY mic. But don't you think it's a little bit wrong to claim these as yours. I was using both before you posted them. Theyre all over the web and have been used a long time. Although I recently started using both, I read about them on the web years ago.

Appreciated either way. And the mating to REW walkthrough is new afaik.
tuxedocivic is offline  
post #6 of 52 Old 06-11-2011, 07:12 PM
AVS Special Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 8,417
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 329 Post(s)
Liked: 210
Quote:
Originally Posted by tuxedocivic View Post

I appreciate you posting this, and the DIY mic. But don't you think it's a little bit wrong to claim these as yours. I was using both before you posted them. Theyre all over the web and have been used a long time.

If he bought the parts and built them, I'd say they are his.
Roger Dressler is offline  
post #7 of 52 Old 06-11-2011, 07:21 PM
AVS Special Member
 
tuxedocivic's Avatar
 
Join Date: Feb 2010
Location: Ladysmith, BC
Posts: 4,532
Mentioned: 4 Post(s)
Tagged: 1 Thread(s)
Quoted: 236 Post(s)
Liked: 497
Quote:
Originally Posted by Roger Dressler View Post

If he bought the parts and built them, I'd say they are his.

I didn't mean to be rude, and sharing the info is appreciated. I just meant that he (perhaps inadvertently) coined the linkwitz WM61a panasonic mic the lilmike mic. Most forums just call it the WM61A. If I own a Behringer 8000 mic I don't call it the tuxedocivic mic. Just sayin'.

Thanks though.
tuxedocivic is offline  
post #8 of 52 Old 06-11-2011, 07:25 PM - Thread Starter
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,184
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 13 Post(s)
Liked: 80
Quote:
Originally Posted by tuxedocivic View Post

I appreciate you posting this, and the DIY mic. But don't you think it's a little bit wrong to claim these as yours. I was using both before you posted them. Theyre all over the web and have been used a long time. Although I recently started using both, I read about them on the web years ago.

Appreciated either way. And the mating to REW walkthrough is new afaik.

Agreed.

I have edited the first post to reflect that this is not my invention, simply my interpretation and adaptation of what has already been done, similar to what I did with the mic.

More to come.
lilmike is offline  
post #9 of 52 Old 06-11-2011, 07:26 PM - Thread Starter
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,184
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 13 Post(s)
Liked: 80
Quote:
Originally Posted by tuxedocivic View Post

I didn't mean to be rude, and sharing the info is appreciated. I just meant that he (perhaps inadvertently) coined the linkwitz WM61a panasonic mic the lilmike mic. Most forums just call it the WM61A. If I own a Behringer 8000 mic I don't call it the tuxedocivic mic. Just sayin'.

Thanks though.

Actually, for the mic, I changed Linkwitz's circuit design slightly, most notably, I made it a simpler, monaural version more suited to acoustic measurements.

As with the mic, I did not buy any of this off the shelf, I bought raw parts and made something out of them.

I'd be happy to stop posting these sorts of how-to's, I have plenty of other things I could be doing.
lilmike is offline  
post #10 of 52 Old 06-11-2011, 07:32 PM
Advanced Member
 
Audiophile34's Avatar
 
Join Date: Apr 2011
Location: Detriot Mi area
Posts: 561
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Just cause some people get there (panties) in a bunch cause they did not post something first, dont let that make you stop Mike. I DEFINATLY appreciate all the how to's and the what not to do's that you have sprinkled all over this forum..

So please keep them coming..

My first DIY project. A dual, dual opposed setup

www.avsforum.com/avs-vb/showthread.php?t=1345494
Audiophile34 is offline  
post #11 of 52 Old 06-11-2011, 07:33 PM
AVS Special Member
 
tuxedocivic's Avatar
 
Join Date: Feb 2010
Location: Ladysmith, BC
Posts: 4,532
Mentioned: 4 Post(s)
Tagged: 1 Thread(s)
Quoted: 236 Post(s)
Liked: 497
No not at all. They're very appreciated. I actually could use the help right now. Thanks for adding the source info

If I may add, I think this is good to spread the word on this jig. I'm surprised how many people on this forum are designing enclosures based on manufactures specs. This simple jig can optimize designs and should be widely used.

Kudos lilmike. Your info about these cheap testing devices and your sub designs are a big help to a lot of people.

PS. I forgot you revised the phantom power for the wm61a to lower corner frequency. For that, we shall call it the lilmike mic
tuxedocivic is offline  
post #12 of 52 Old 06-11-2011, 07:36 PM
AVS Special Member
 
tuxedocivic's Avatar
 
Join Date: Feb 2010
Location: Ladysmith, BC
Posts: 4,532
Mentioned: 4 Post(s)
Tagged: 1 Thread(s)
Quoted: 236 Post(s)
Liked: 497
Quote:
Originally Posted by Audiophile34 View Post

Just cause some people get there (panties) in a bunch cause they did not post something first, dont let that make you stop Mike. I DEFINATLY appreciate all the how to's and the what not to do's that you have sprinkled all over this forum..

So please keep them coming..

It has nothing so with who posted it first. Actually I did post about it in my build first. Actually lilmike even offered advice to me in my build, so that was definetely not my intention. I dont care who posted first. I just believe in giving credit where it is due. Which, lilmike did do in his mic thread. And now has done here.
tuxedocivic is offline  
post #13 of 52 Old 06-11-2011, 07:41 PM
Advanced Member
 
Audiophile34's Avatar
 
Join Date: Apr 2011
Location: Detriot Mi area
Posts: 561
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Darn pushy Canadians. lol

My first DIY project. A dual, dual opposed setup

www.avsforum.com/avs-vb/showthread.php?t=1345494
Audiophile34 is offline  
post #14 of 52 Old 06-12-2011, 02:19 PM - Thread Starter
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,184
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 13 Post(s)
Liked: 80
Lots of updates posted.
lilmike is offline  
post #15 of 52 Old 06-12-2011, 02:31 PM
Advanced Member
 
Steve_Vai_rules's Avatar
 
Join Date: Jul 2010
Location: The land of Ice and Snow
Posts: 988
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 15
wow this is great!

Matt

"The main reason Santa is so jolly is because he knows where all the bad girls live." - George Carlin
Steve_Vai_rules is offline  
post #16 of 52 Old 06-12-2011, 03:00 PM
AVS Addicted Member
 
LTD02's Avatar
 
Join Date: Oct 2003
Posts: 16,121
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 198 Post(s)
Liked: 914
that is a really nice write up.

the thiele small measurements look good to. remember that the factory measurements tend to have some slop in them already. so even if measured perfectly, the driver specs probably wouldn't match perfectly the factory specs.

Listen. It's All Good.
LTD02 is offline  
post #17 of 52 Old 06-12-2011, 06:08 PM
AVS Special Member
 
maxmercy's Avatar
 
Join Date: Nov 2008
Posts: 2,335
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked: 131
Outstanding. Subscribed.

JSS
maxmercy is offline  
post #18 of 52 Old 06-12-2011, 07:05 PM
AVS Special Member
 
Ricci's Avatar
 
Join Date: Mar 2007
Location: Louisville KY
Posts: 5,088
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked: 192
Good stuff Mike. Your jig looks WAY better than the messy set-up that I always use. The low frequency rise is a little odd though. I get the opposite sometimes which is to say that the impedance will drop off instead of rise.
Ricci is offline  
post #19 of 52 Old 06-12-2011, 07:58 PM - Thread Starter
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,184
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 13 Post(s)
Liked: 80
Quote:
Originally Posted by Ricci View Post
Good stuff Mike. Your jig looks WAY better than the messy set-up that I always use. The low frequency rise is a little odd though. I get the opposite sometimes which is to say that the impedance will drop off instead of rise.
Thanks.

The rise is definitely weird. I've been messing with this all afternoon (cause I can't do much else......). I have tried different sense resistors, measured the sense resistors with my WT2, all kinds of stuff. Currently, it looks like it is the roll off of the UCA-202's headphone amp that is causing the issue. With the lower sense resistor, things are pretty much OK to 20 Hz.

Unfortunately, it looks like I'll need a bit more of an amp to get an accurate LF impedance measurement. I was hoping to avoid that, higher-level signals damage things.... Last time I tried a divider circuit, I smoked my M-Audio transit.
lilmike is offline  
post #20 of 52 Old 06-12-2011, 08:44 PM
AVS Special Member
 
Ricci's Avatar
 
Join Date: Mar 2007
Location: Louisville KY
Posts: 5,088
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked: 192
Don't be too upset I smoked the high level input on a V/I Box last week. Talked to them and they say it is the first. The lead up to that was me investigating the same sort of thing. My impedance measurments with it into REW just do not seem quite right. I get a roll off down under 1ohm below 10hz when I know damn well the sub never gets below 4ohms and I get a weird top end roll off as well. Between about 10-200hz it seems close enough and that is the range I need it for but I just can't help myself. I can pull out my scrapped together impedance jig and get results that are dead on with what a WT2 shows. Now I am worrying about doing the high power tests through it.
Ricci is offline  
post #21 of 52 Old 06-13-2011, 03:01 PM
AVS Special Member
 
DS-21's Avatar
 
Join Date: Jun 2005
Posts: 3,376
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 64 Post(s)
Liked: 166
Quote:
Originally Posted by Ricci View Post

Good stuff Mike. Your jig looks WAY better than the messy set-up that I always use.

Indeed. I've been using a cobbled-together cord with resistors on it, based on the schematic in the manual for FuzzMeasure. Your boxed idea is much more elegant.

Way to get people to up their game, Mike!

--
"In many cases there aren’t two sides unless one side is 'reality' and the other is 'nonsense.'" - Phil Plait
Serious Audio Blog 
Multichannel music (and video) urban loft living room system 
DS-21 is offline  
post #22 of 52 Old 08-04-2011, 08:29 PM
AVS Special Member
 
CZ Eddie's Avatar
 
Join Date: Nov 2000
Location: Austin TX, USA
Posts: 7,062
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Liked: 13
Quote:
Originally Posted by lilmike View Post

I use the Behringer UCA-202 soundcard for the bulk of my measurements now..

Good stuff, Mike.
Thanks a bunch for the un-solicited assist!

Just curious. Are you using the UCA-202 for all REW functions, such as testing your room response. Or just for the woofer testing? I was a little unclear on that part. I assume any soundcard with 1/8 mini-din's will work.

I'd been thinking about getting a WT3 but might hold off on that after reading this thread.

"The boom is dead, long live the bass"
CZ Eddie is offline  
post #23 of 52 Old 08-04-2011, 09:17 PM - Thread Starter
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,184
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 13 Post(s)
Liked: 80
Quote:
Originally Posted by CZ Eddie View Post

Good stuff, Mike.
Thanks a bunch for the un-solicited assist!

Just curious. Are you using the UCA-202 for all REW functions, such as testing your room response. Or just for the woofer testing? I was a little unclear on that part. I assume any soundcard with 1/8 mini-din's will work.

I'd been thinking about getting a WT3 but might hold off on that after reading this thread.

Pretty much all of it. I don't do much room correction stuff though, as mine is basically a lost cause... I'll fix it with an excavator.....

I do use the UCA-202 for crossover design, as well as all of my SPL testing.
lilmike is offline  
post #24 of 52 Old 08-11-2011, 07:38 PM
Newbie
 
OldShark's Avatar
 
Join Date: Aug 2011
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Hi lilmike.

ru use ASIO or JAVA with the UCA-202 in REW?
[]'s
OldShark is offline  
post #25 of 52 Old 08-12-2011, 09:30 AM - Thread Starter
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,184
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 13 Post(s)
Liked: 80
Quote:
Originally Posted by OldShark View Post

Hi lilmike.

ru use ASIO or JAVA with the UCA-202 in REW?
[]'s

When using the UCA202 as described above, I select "USB Audio CODEC" under device, then select "SPEAKER" under output and "MICROPHONE" on the input. I run it at 48KHz. I believe that this is the ASIO driver, but I am not certain.

Edit - For Clarification, this is the JAVA driver.
lilmike is offline  
post #26 of 52 Old 08-12-2011, 10:18 AM
Newbie
 
OldShark's Avatar
 
Join Date: Aug 2011
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Hi lilmike.

Ok. Here using REW V5.10 beta 7 anda UCA-202 for TS and TASCAM US-144 + EMC8000 (mic) for SPL and RTA.

My measurements with ASIO driver is better than JAVA.
OldShark is offline  
post #27 of 52 Old 08-15-2011, 11:26 AM - Thread Starter
AVS Special Member
 
lilmike's Avatar
 
Join Date: Dec 2009
Location: Pacific Northwest
Posts: 2,184
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 13 Post(s)
Liked: 80
Quote:
Originally Posted by lilmike View Post

When using the UCA202 as described above, I select "USB Audio CODEC" under device, then select "SPEAKER" under output and "MICROPHONE" on the input. I run it at 48KHz. I believe that this is the ASIO driver, but I am not certain.

As I was not using the beta version of REW, the above (as well as all of my measurements to date) use the Java sound driver. I just installed 5.01B7, and just installed the ASIO drivers from Behringer for my UCA202 (get them here (direct link for OEM Windows X86)). No time to measure anything right now, but I will report back if I see any differences.
lilmike is offline  
post #28 of 52 Old 08-15-2011, 08:43 PM
Member
 
tculverhouse's Avatar
 
Join Date: Aug 2008
Posts: 29
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Protip for the added mass method:

US Nickel Specification = 5.000 g
US Penny Specification = 2.500 g

(source)

-Tim
tculverhouse is offline  
post #29 of 52 Old 11-14-2011, 12:26 AM
Senior Member
 
aackthpt's Avatar
 
Join Date: Sep 2004
Location: In the mitten, USA
Posts: 358
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 17
I just built a version of this jig... as somebody noted mostly scrapped. I bought 1 watt/47 ohm resistors, RCAs and binding posts - the rest was pulled from a box around the house. Can't wait to give something a test with it.

Thanks for posting the plans; this will be a valuable tool and saved me some cash.

aackthpt is online now  
post #30 of 52 Old 01-04-2012, 08:42 PM
Advanced Member
 
Socketman's Avatar
 
Join Date: Jan 2007
Posts: 684
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Liked: 65
So yeah i realize this is an old thread but still so very valuable. Just had do a shout out to lilmike for his excellent walkthrough. I am just starting out with all this speaker building and testing etc. Great site ,hopefully i wont have to ask too many questions. I tend to search and read alot before asking. So again thank lil and see ya all around.
Socketman is offline  
Reply DIY Speakers and Subs

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off