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Whatever happened to DCM's Steve Eberbach? - Page 43

post #1261 of 1643
Wow.
Lots of good stuff. Investment vs return. Performance gain better looked at in better, simpler areas?

The main point when I scoured Audio Quest's website that stuck out to me was using a separated mono filament, to fight magnetic interaction that supposedly occurs in multi filament line. Remember, house a/c current is routed on mono filament. I am no electrical engineer (mechanical), but other than cost (?) I am sure there are sound engineering principals behind this. Is this a measurable improvement without a lot of very expensive equipment? Probably not. Is it an improvement, no matter how small? I would have to lean toward yes, because even in blind tests, it can sound better, which makes the results at least partially objective.

I can say that I have pursued many of the simple tips. I measure my side wall and back wall distances and angles with a tape at least once a month. ( I have kids, and I do go behind my system once in a while to make cable and Video signal path changes for recording purposes so my speakers get bumped from time to time) I am careful about cable routing, making sure no signal path parallels a/c closer than 18" as much as possible.

Will it make me feel better to have a good set of cables for my main fronts? Yes to that also. ;-))
post #1262 of 1643
Out of curiosity, what are these blind tests you refer to and what are the electrical characteristics that constitute good cables? Submitted for your reading pleasure, here's what happened when the president of Transparent cable voiced his certainty regarding the superiority of better cables: http://www.vxm.com/21R.64.html

If what you really want are cables that have a certain panache or style commensurate with your equipment, there's an active thread in the Speaker Section detailing various builds with pics.
post #1263 of 1643
Again, I didn't mean to start anything here, I just wanted suggestions to replace a single pair of front cables (out of the many fronts I have).

So what you are basing your current views on is an almost 20 year old opinion? That would be akin to saying I'll use a basic cap for a replacement for my DCMs rather than a quality Erse (or even a Pulse X) just because they were adequate (and the best there was available) back then. You really don't believe huge strides have been made in manufacturing and quality control in production in the last 20 years? Just because you can't measure the difference with a decibel meter at home doesn't mean there isn't a difference in conductivity.

There is an audible difference with some cable. Many will agree with me. Look at what you use for pre-amp cable. Is it Radio Shack, Monster, or Audio Quest? Why?

Is the investment worth the return? To some it is.
post #1264 of 1643
Quote:
Originally Posted by Mr. Bubbles View Post

Ripple;.... I'm having Sanford and Son flashbacks.biggrin.gif

I going to sidestep the last several post and just say, I prefer Champipple (a portmanteau of champagne and ripple). LOL

http://www.youtube.com/watch?v=Esr4MEu20bs
post #1265 of 1643
For me, a good IPA, or more simply, good Tequila + a suitable mixer (or straight up of course) ))
post #1266 of 1643
Which sub?
post #1267 of 1643
Quote:
Originally Posted by Zoomin600 View Post

Again, I didn't mean to start anything here, I just wanted suggestions to replace a single pair of front cables (out of the many fronts I have).

So what you are basing your current views on is an almost 20 year old opinion?
That wasn't an opinion. It was a story about a guy who made a claim and then when someone actually took him up on, bailed. You won't find too many vendors of boutique cable looking to make that same mistake. Now, about those blind tests you mentioned?
Quote:
That would be akin to saying I'll use a basic cap for a replacement for my DCMs rather than a quality Erse (or even a Pulse X) just because they were adequate (and the best there was available) back then.
Best is a relative word and the selection of parts and other matters is heavily driven by the bottom line. Unless you're prepared to undertake some sot of comprehensive measurements, changing parts that significantly differ in their electrical properties from the original can have unintended consequences.
Quote:
You really don't believe huge strides have been made in manufacturing and quality control in production in the last 20 years? Just because you can't measure the difference with a decibel meter at home doesn't mean there isn't a difference in conductivity.
Sure. And if you go from 3 meters of cable to 2.5 there's also a difference. So what?
Quote:
There is an audible difference with some cable. Many will agree with me. Look at what you use for pre-amp cable. Is it Radio Shack, Monster, or Audio Quest? Why?

Is the investment worth the return? To some it is.
of course many will agree and many will agree that homeopathy works, placing wooden blocks under your equipment, and the list goes on. People are driven to select stuff for any number of reasons but it's more driven by marketing than anything else. If you want to make fundamental improvements to your existing system, learn to measure, follow some of the threads on software packages like REW, and see some of the threads on ETC.
post #1268 of 1643
Quote:
That wasn't an opinion. It was a story about a guy who made a claim and then when someone actually took him up on, bailed. You won't find too many vendors of boutique cable looking to make that same mistake. Now, about those blind tests you mentioned?
And, again, it was almost 20 years ago. Tech that might have been weak, or not. Save wine, cognac, audio components, and older Mopars, is 20 year old anything relevant anymore? I never mentioned a specific blind test, but if I listened to two full albums with each set of cables, I'll bet I could pick one over the other. Not which one is 'better', but at least differences within the two.
Quote:
Best is a relative word and the selection of parts and other matters is heavily driven by the bottom line. Unless you're prepared to undertake some sot of comprehensive measurements, changing parts that significantly differ in their electrical properties from the original can have unintended consequences.
Based on what I've read here, Mr. Eberbach made very few compromises when it came to his crossover designs. Seeing as the cost of these caps are within a couple dollars, and it was more or less his company, I honestly think Steve probably chose the best cap available. And as I've said, today the quality is much better even for a relatively inexpensive cap. They don't differ in electrical properties, they just have less of a chance to do so under use/load. Why wouldn't the manufacturing process also follow for copper, cable assembly, and termination?
Quote:
Quote:
You really don't believe huge strides have been made in manufacturing and quality control in production in the last 20 years? Just because you can't measure the difference with a decibel meter at home doesn't mean there isn't a difference in conductivity.
Sure. And if you go from 3 meters of cable to 2.5 there's also a difference. So what?
Huh?

It's probably a good idea to eventually spend some good money on measuring equipment and software, right now my birthday money is going toward some good cable.

And I know you don't use Radio Shack preamp cables. Why not?
Edited by Zoomin600 - 5/17/13 at 4:48pm
post #1269 of 1643
Quote:
Originally Posted by Zoomin600 View Post

And, again, it was almost 20 years ago. Tech that might have been weak, or not. Save wine, cognac, audio components, and older Mopars, is 20 year old anything relevant anymore? I never mentioned a specific blind test, but if I listened to two full albums with each set of cables, I'll bet I could pick one over the other. Not which one is 'better', but at least differences within the two.
Based on what I've read here, Mr. Eberbach made very few compromises when it came to his crossover designs. Seeing as the cost of these caps are within a couple dollars, and it was more or less his company, I honestly think Steve probably chose the best cap available. And as I've said, today the quality is much better even for a relatively inexpensive cap. They don't differ in electrical properties, they just have less of a chance to do so under use/load. Why wouldn't the manufacturing process also follow for copper, cable assembly, and termination?
Huh?

It's probably a good idea to eventually spend some good money on measuring equipment and software, right now my birthday money is going toward some good cable.

And I know you don't use Radio Shack preamp cables. Why not?

You're right. Cable technology has changed dramatically. They look much cooler now, and can cost way more too!

I bet you *can* tell the difference between two sets of cables, as long as you know before-hand which is which.

Have fun wasting your birthday money! tongue.gif
post #1270 of 1643
Quote:
Originally Posted by flyng_fool View Post

Which sub?

Going for an Outlaw EX. I was just about to push the button on the recent "B" stock sale when the TW3s became available. They'll have another sale, I'm sure. The downside is, I'll have to get underneath the house again to run more wire. biggrin.gif
post #1271 of 1643
Quote:
Originally Posted by Zoomin600 View Post

And, again, it was almost 20 years ago. Tech that might have been weak, or not. Save wine, cognac, audio components, and older Mopars, is 20 year old anything relevant anymore? I never mentioned a specific blind test, but if I listened to two full albums with each set of cables, I'll bet I could pick one over the other. Not which one is 'better', but at least differences within the two.
Based on what I've read here, Mr. Eberbach made very few compromises when it came to his crossover designs. Seeing as the cost of these caps are within a couple dollars, and it was more or less his company, I honestly think Steve probably chose the best cap available. And as I've said, today the quality is much better even for a relatively inexpensive cap. They don't differ in electrical properties, they just have less of a chance to do so under use/load. Why wouldn't the manufacturing process also follow for copper, cable assembly, and termination?
Huh?

It's probably a good idea to eventually spend some good money on measuring equipment and software, right now my birthday money is going toward some good cable.

And I know you don't use Radio Shack preamp cables. Why not?
post #1272 of 1643
[
Quote:
Originally Posted by Zoomin600 View Post

And, again, it was almost 20 years ago. Tech that might have been weak, or not. Save wine, cognac, audio components, and older Mopars, is 20 year old anything relevant anymore? I never mentioned a specific blind test, but if I listened to two full albums with each set of cables, I'll bet I could pick one over the other. Not which one is 'better', but at least differences within the two.
Well you did say there were blind tests that supported your thoughts on cables. Perhaps you misspoke and meant something else. As to your thoughts on being able to differentiate, the thing is, can you do it to a level that essentially rules out random chance. As an ME you've taken statistical courses so you'd be familiar with hitting a 95% confidence level. Go for it.
Quote:
Based on what I've read here, Mr. Eberbach made very few compromises when it came to his crossover designs. Seeing as the cost of these caps are within a couple dollars, and it was more or less his company, I honestly think Steve probably chose the best cap available.
Listen, I loved the original lineup DCM offered and had hoped it would just continue. But it would be naive to think Eberbach didn't make compromises. As to his costs when buying in bulk, who knows. Sometimes spending more doesn't get you anything except higher costs that have to be passed on to the consumer. Sometimes that's warranted because if the consumer doesn't see something like say air core inductors but instead finds iron core ones they may shun the product.
Quote:
And as I've said, today the quality is much better even for a relatively inexpensive cap. They don't differ in electrical properties, they just have less of a chance to do so under use/load. Why wouldn't the manufacturing process also follow for copper, cable assembly, and termination?
What do you base this sweeping generalization on? Caps most certainly differ in electrical properties, reliability, application, etc. and what do you think of manufacturers who take an existing cap, make a cosmetic change and then charge significantly more?
Quote:
Huh?

It's probably a good idea to eventually spend some good money on measuring equipment and software, right now my birthday money is going toward some good cable.

And I know you don't use Radio Shack preamp cables. Why not?
I'd have no problem using them. Interconnects are even less important but if you're into those, get the ones with the least capacitance.

And aren't you a little old to be getting birthday money?tongue.gif
post #1273 of 1643
Quote:
As an ME you've taken statistical courses so you'd be familiar with hitting a 95% confidence level. Go for it.
As previously stated, I can tell the difference sonically.
Quote:
What do you base this sweeping generalization on? Caps most certainly differ in electrical properties, reliability, application, etc. and what do you think of manufacturers who take an existing cap, make a cosmetic change and then charge significantly more?
Of course caps have different values. No one said any different. That's why there is an almost infinite selection. But with better quality components and manufacturing there are closer tolerances and more resistance to ripple. Now, if that manufacturing tech didn't exist 20 years ago, how could you know if there was anything better?
Quote:
And aren't you a little old to be getting birthday money?
My wife gave up a long time ago. She lets me pick at least one myself.biggrin.gif
post #1274 of 1643
1 am on the east coast.....small party.....Champipple was a big hit. My buddies said they've never heard anything so good.
post #1275 of 1643


I spent some more time on my TW3's today. I checked the resistance values of all of the resistors on both of the crossovers.

The picture above has the values that I measured for the left crossover. The "stamped as" indication is what is marked on the individual resistor. Resistors 4, 5 and 6 did not have ohm values marked on them so I don't know what to compare my measurements to. I don't know how much the values can deviate from their marked values before they should be replaced and would value the input of those more knowledgeable.

The values I measured for the right speaker are:

#1 --- 15.8 ohms
#2 --- 5.2 ohms
#3 --- 16.1 ohms
#4 --- 16.6 ohms
#5 --- 1.3 ohms
#6 --- 1.3 ohms
#7 --- 3.1 ohms
#8 Oops...just realized I skipped a number! There is no resistor marked #8
#9 --- 8.8 ohms
#10 --- 49.7ohms
#11 --- 49.6 ohms
#12 --- 48.7 ohms

Also note that on the right crossover the #3 resistor in the picture above is installed where #4 is, and #4 is installed where # 3 is installed. In other words, my right crossover has #3 and #4 reversed.
post #1276 of 1643
When reworking some crossovers for my Timewindows and Timeframe 500s I replaced all the resistors as they were out of spec. I used Mills resistors where space would allow it and sandbar resistors where I had to. See post #1174 for pics.
post #1277 of 1643
This is a follow up to my post #1275 (2 up from this one) and my questions below reference the picture in that post. I'm hoping someone can help verify the following for me.

1. All the resistors are spec'd with a 5% tolerance?
2. Resistor #4 is a 15 ohm 5 watt resistor?
3. What are the spec's (ohms, watts and tolerance) for resistors #5 & #6? I'm assuming they are ceramic resistors.
4. Resistor #9 is a 10 watt resistor? (It is stamped as "IRC 8746 PW10A 7.5 ohm 5%".)
5, Resistor #10. #11 & #12 are 5 watt resistors? (They are stamped as "Colber 47 ohm 5% CW5")

From my measurements, if all of the resistors are 5% tolerance then, there is a significant amount of resistors that are out of spec and should be replaced. I'm trying to confirm that I have the correct specification for them before I order new ones.

I am considering replacing them with either the Xicon PW-RC series (data sheet here http://www.mouser.com/ds/2/351/XC-600041-198125.pdf)

Or Mills resistors with a 1% tolerance (data sheet here http://www.millsresistor.com/pdf/pg16prn.pdf). Alternatively, I could use the mills 5% tolerance, this place seems to have some good pricing on them http://speaker.rosaryshop.com/index.php/r/components.

At the risk of opening a can of worms, I'd appreciate your thoughts on the benefits/drawbacks of the Xicon and the Mills.
post #1278 of 1643
Quote:
Originally Posted by TonyTW3 View Post

This is a follow up to my post #1275 (2 up from this one) and my questions below reference the picture in that post. I'm hoping someone can help verify the following for me.

1. All the resistors are spec'd with a 5% tolerance?
2. Resistor #4 is a 15 ohm 5 watt resistor?
3. What are the spec's (ohms, watts and tolerance) for resistors #5 & #6? I'm assuming they are ceramic resistors.
4. Resistor #9 is a 10 watt resistor? (It is stamped as "IRC 8746 PW10A 7.5 ohm 5%".)
5, Resistor #10. #11 & #12 are 5 watt resistors? (They are stamped as "Colber 47 ohm 5% CW5")

From my measurements, if all of the resistors are 5% tolerance then, there is a significant amount of resistors that are out of spec and should be replaced. I'm trying to confirm that I have the correct specification for them before I order new ones.

I am considering replacing them with either the Xicon PW-RC series (data sheet here http://www.mouser.com/ds/2/351/XC-600041-198125.pdf)

Or Mills resistors with a 1% tolerance (data sheet here http://www.millsresistor.com/pdf/pg16prn.pdf). Alternatively, I could use the mills 5% tolerance, this place seems to have some good pricing on them http://speaker.rosaryshop.com/index.php/r/components.

At the risk of opening a can of worms, I'd appreciate your thoughts on the benefits/drawbacks of the Xicon and the Mills.

1. The "J" on the resistors means that they are 5% tolerance.
2. Yes
3. #5 and #6 are not resistors. They are polyswitches for circuit protection.
4. Yes
5. Yes

The Xicon PW-RC series are fine.

#2 and #3 are running parallel with each other and #9 is running parallel to the variable resistor Cal 2. This will give you an inaccurate reading.

My opinion is to leave them alone. Wire wound resistor shouldn't lose there values. If they fail it would show as open. Steve said his designs allow for these variance in values, so I wouldn't be concerned.
post #1279 of 1643
Quote:
Originally Posted by Jamie Hauser View Post


#2 and #3 are running parallel with each other and #9 is running parallel to the variable resistor Cal 2. This will give you an inaccurate reading.

Thanks for the feedback Jamie. With regard to #2, #3 and #9, on each I desoldered one lead from the board when I measured them. (To be more precise, I did that with every capacitor I measured.) It was my understanding that as long as one side of the resistor was not connected to anything I would get an accurate reading, Was my assumption incorrect?
Quote:
Originally Posted by Jamie Hauser View Post

My opinion is to leave them alone. Wire wound resistor shouldn't lose there values. If they fail it would show as open. Steve said his designs allow for these variance in values, so I wouldn't be concerned.

Capacitor #7 has a variance of 61% in the left speaker and 72% in the right one. Would Steve's designs allow for that much variance?

As I mentioned before, the treble in these TW3's sounds weak to me. For example, a high hat sounds much more distant and in the background than it does in either my 7's or 1000's. It does not sound crisp. My goal in measuring the resistors was to see if there may be something out of spec that would be causing this. I am not sure which of the resistors are in the high frequency circuit, but would some of the resistors that had higher variance be in that circuit?

As an aside, when I had them apart to measure the resistors I also checked the resistance of the drivers thinking something might be out of spec. Here's what I got:

Left speaker.................................... Right Speaker
5.9 ohms....... outside main driver....... 5.9 ohms
7.2 ohms....... outside tweeter............7.4 ohms
5.9 ohms....... inside main driver..........5.7 ohms
7.4 ohms....... inside tweeter............. 7.3 ohms

When I measured the main drivers I did so with out any wires attached to them. On the tweeters I desoldered the red leads and then measured across to the blue and purple wire where they were soldered to the variable resistor.
post #1280 of 1643
Parts Express carries Mills and Xicon also. If they were my crossovers I'd replace all of them. I'd also replace those two mylar caps that are outside of the time delay circuit. The cost is negligible if you DIY and you'll have practically brand new crossovers. Even Mills resistors are cheap compared to using high end metalized polypropylene capacitors.

http://www.parts-express.com/cat/audio-grade-non-inductive-resistors/301?kg=768|2497

http://www.parts-express.com/cat/wire-wound-resistors/303?kg=769|2121
post #1281 of 1643
Quote:
Originally Posted by TonyTW3 View Post

Quote:
Originally Posted by Jamie Hauser View Post


#2 and #3 are running parallel with each other and #9 is running parallel to the variable resistor Cal 2. This will give you an inaccurate reading.

Thanks for the feedback Jamie. With regard to #2, #3 and #9, on each I desoldered one lead from the board when I measured them. (To be more precise, I did that with every capacitor I measured.) It was my understanding that as long as one side of the resistor was not connected to anything I would get an accurate reading, Was my assumption incorrect?
Quote:
Originally Posted by Jamie Hauser View Post

My opinion is to leave them alone. Wire wound resistor shouldn't lose there values. If they fail it would show as open. Steve said his designs allow for these variance in values, so I wouldn't be concerned.

Capacitor #7 has a variance of 61% in the left speaker and 72% in the right one. Would Steve's designs allow for that much variance?

As I mentioned before, the treble in these TW3's sounds weak to me. For example, a high hat sounds much more distant and in the background than it does in either my 7's or 1000's. It does not sound crisp. My goal in measuring the resistors was to see if there may be something out of spec that would be causing this. I am not sure which of the resistors are in the high frequency circuit, but would some of the resistors that had higher variance be in that circuit?

As an aside, when I had them apart to measure the resistors I also checked the resistance of the drivers thinking something might be out of spec. Here's what I got:

Left speaker.................................... Right Speaker
5.9 ohms....... outside main driver....... 5.9 ohms
7.2 ohms....... outside tweeter............7.4 ohms
5.9 ohms....... inside main driver..........5.7 ohms
7.4 ohms....... inside tweeter............. 7.3 ohms

When I measured the main drivers I did so with out any wires attached to them. On the tweeters I desoldered the red leads and then measured across to the blue and purple wire where they were soldered to the variable resistor.

You measured correctly.

Capacitor #7? I assuming you mean resistor #7. It's part of the tweeter circuit along with #9, 10, 11, and 12. Yes I do believe it was compensated for.
post #1282 of 1643
Quote:
Originally Posted by Doctor Morbius View Post

Parts Express carries Mills and Xicon also. If they were my crossovers I'd replace all of them. I'd also replace those two mylar caps that are outside of the time delay circuit. The cost is negligible if you DIY and you'll have practically brand new crossovers. Even Mills resistors are cheap compared to using high end metalized polypropylene capacitors.

http://www.parts-express.com/cat/audio-grade-non-inductive-resistors/301?kg=768|2497

http://www.parts-express.com/cat/wire-wound-resistors/303?kg=769|2121

I doubt that changing the resistors will solve his concerns. Any out of spec resistor could have been easily compensated for when the factory adjusted Cal 1 and Cal 2. Actually by replacing them now with the correct spec resistors could change everything. That's assuming that Cal and Cal 2 weren't changed by someone after the fact. When you think about it, the resisters in question are only out by 1 or 2 ohms. There's two user controlled variable resistor (Tweeter Level and HFD) that should have the most effect on the tweeter output in the crossover design. The Tweeter Level control is 50 ohm and the HFD is 25 ohm. This is were I would look closer at.
post #1283 of 1643
Quote:
Originally Posted by Jamie Hauser View Post

I doubt that changing the resistors will solve his concerns. Any out of spec resistor could have been easily compensated for when the factory adjusted Cal 1 and Cal 2. Actually by replacing them now with the correct spec resistors could change everything. That's assuming that Cal and Cal 2 weren't changed by someone after the fact. When you think about it, the resisters in question are only out by 1 or 2 ohms. There's two user controlled variable resistor (Tweeter Level and HFD) that should have the most effect on the tweeter output in the crossover design. The Tweeter Level control is 50 ohm and the HFD is 25 ohm. This is were I would look closer at.

This helped me to better understand your previous post about how Steve had designed the speakers to account for variances in the components. I do believe that Cal 1, Cal 2 and Cal 3 were changed from the original settings in the factory. As part of checking out the speakers, I cleaned and measured the resistance values of all of the Cal resistors. They are all within spec. However, before I moved them I noted where the were set by reading the resistance they were set at as I wanted to make sure I could set them where they were after I moved them. Every Cal resistor was set to the lowest resistance value possible in the resistor - they were cranked all the way open.

As you previously mentioned, Steve mentioned that the Cal resistors would typically be set somewhere near the middle and it would be unusual for all of the resistors to be all the way open. On your recommendation I set all of the Cal resistors to their halfway point (as measured with an ohm meter). The sound definitely improved, but it still seems off in the treble. I'm not opposed to playing around with them some more to see if it helps.

With that in mind I have a couple of questions.

The manual says, "Cal 1 - adjusts tweeter level and time domain compensation at 4 kHz relative to 12.5 kHz."

What is "time domain compensation"? And what should I be listening for in setting it?

What is meant by 4 kHz relative to 12.5 kHz?

The manual says, "Cal 2 - adjust tweeter level at 4kHz off axis."

What is meant by off-axis?
post #1284 of 1643
Quote:
Originally Posted by Jamie Hauser View Post

You measured correctly.

Capacitor #7? I assuming you mean resistor #7. It's part of the tweeter circuit along with #9, 10, 11, and 12. Yes I do believe it was compensated for.

You are correct, I meant resistor. My typo.
post #1285 of 1643
Can someone please confirm that the lower ports on the TW3 would be on the outboard side (facing the ambient soundfield) when correctly placed?
post #1286 of 1643
Quote:
Originally Posted by TonyTW3 View Post

Can someone please confirm that the lower ports on the TW3 would be on the outboard side (facing the ambient soundfield) when correctly placed?

Yes, they're on the out board side.
post #1287 of 1643
Ugh, Gentlemen.
I should have paid attention when everyone was stating Erse has backordered many caps. After finding the Pulse X cap for my TF600 was temporarily out of stock, I measured the board and decided the 400volt cap would fit, and it went backorder the day I finally placed my order Is there any other vendor for a quality cap that meets these specs?
Capacitance 15 µF
Voltage Rating 250 VDC
Tolerance 3.0%
Dissipation Factor .0004
Outside Diameter 26 mm
Length 38 mm
Wire Diameter 1 mm
Lead Length 40 mm
RoHS Compliant Yes RoHS Compliant
Weight: .047 lb

Thanks, and happy listening.
post #1288 of 1643
Quote:
Originally Posted by TonyTW3 View Post

Quote:
Originally Posted by Jamie Hauser View Post

I doubt that changing the resistors will solve his concerns. Any out of spec resistor could have been easily compensated for when the factory adjusted Cal 1 and Cal 2. Actually by replacing them now with the correct spec resistors could change everything. That's assuming that Cal and Cal 2 weren't changed by someone after the fact. When you think about it, the resisters in question are only out by 1 or 2 ohms. There's two user controlled variable resistor (Tweeter Level and HFD) that should have the most effect on the tweeter output in the crossover design. The Tweeter Level control is 50 ohm and the HFD is 25 ohm. This is were I would look closer at.

This helped me to better understand your previous post about how Steve had designed the speakers to account for variances in the components. I do believe that Cal 1, Cal 2 and Cal 3 were changed from the original settings in the factory. As part of checking out the speakers, I cleaned and measured the resistance values of all of the Cal resistors. They are all within spec. However, before I moved them I noted where the were set by reading the resistance they were set at as I wanted to make sure I could set them where they were after I moved them. Every Cal resistor was set to the lowest resistance value possible in the resistor - they were cranked all the way open.

As you previously mentioned, Steve mentioned that the Cal resistors would typically be set somewhere near the middle and it would be unusual for all of the resistors to be all the way open. On your recommendation I set all of the Cal resistors to their halfway point (as measured with an ohm meter). The sound definitely improved, but it still seems off in the treble. I'm not opposed to playing around with them some more to see if it helps.

With that in mind I have a couple of questions.

The manual says, "Cal 1 - adjusts tweeter level and time domain compensation at 4 kHz relative to 12.5 kHz."

What is "time domain compensation"? And what should I be listening for in setting it?

What is meant by 4 kHz relative to 12.5 kHz?

The manual says, "Cal 2 - adjust tweeter level at 4kHz off axis."

What is meant by off-axis?

I did get with Steve on your concerns. He said that it seems to indicate that the tweeters themselves are losing sensitivity and can only recommend replacing them or their low viscosity ferrofluid. Old age and high temperatures can increase the viscosity of the ferrofluid, reducing the sensitivity of the tweeters by over-damping their moving coils and domes.

The use of ferrofluid was for cooling protection due to temporary excessive signal amplitude, while damping was done by electrical low impedance primarily at the tweeter's resonance frequency. When components are modified the completion must be done with the spectrum analyzer, oscilloscope, and impulse/step response signal source.

His comments on the calibration pots:

The calibration is very small adjustment for matching tiny variations to standard using the spectrum analyzer at several off axis of driver and cabinet forward facing angles known to optimize direct path and reverberant path power response. They may have slight audible effects but are not relevant without proper test equipment. If a third-octave pink noise test cannot provide a substantially flat overall response from 100 Hz to 16 kHz in a practical listening direction toward an expected listening position between the speakers, with the speakers pointing straight forward, not pointing out or in toward the center, the "tweeters are bad" in the service and repair jargon..Beyond that, careful "calibration" can improve "imaging" even though overall tone color is basically unchanged for practical purposes, by making speaker polar responses symmetrically matched within less than one dB.

If I were to add my two cents, your not going to be able to correct anything in the crossover except to put the Cal pots all in the center position. You have nothing to lose by playing with them since someone changed their original position from when they were calibrated. You would need specialized equipment to recalibrate them or to check the tweeters themselves.

Time domain compensation deals with time alignment and you would not be able to adjust it by just listening.

On and Off-axis pertains to where the measurement is made in relation ship to the driver.
post #1289 of 1643
Geez, I'm still not paying attention.....I'll try Parts Express first.
post #1290 of 1643
After a several month's long, and strange, trip my TW3's are finally fixed.

I am the fourth owner or the speakers. The guy that sold them to me had them for about a month before he sold them to me. He had gotten them from a friend who had gotten them from the original owner's.

When I bought the speaker I was very careful to check out that I had both a right and left speaker . They are a mirror imaged pair, the top label by the dispersion controls indicated there was a right and left one (arrows pointing in opposite directions). Additionally they have consecutive serial numbers. I am confident they are a matched pair.

Anyway, yesterday I'm cleaning a bunch of old emails out of my inbox and I came across some TW3 info that Penny Hole at DCM had sent me several years ago when I started thinking about getting a pair of 3's.

Time Window 3 Owners Manual & Specifications.pdf 2800k .pdf file

I didn't even remember having it and out of serendipity I came across it yesterday. In the info there's a picture that shows the configuration of the speakers with the lower ports on the outboard side of each speaker.

I set mine up as described in the manual with the arrows on the top label facing each other. Well, it turns out that the labels were on the wrong speakers. The left label is on the right speaker and the right one is on the left speaker. As a result, when I set them up as per the manual with the arrows on the labels facing each other the left and right speakers are reversed and the tuning ports are on the inboard side of the speakers.

I had been listening to them like that the whole time. It wasn't until I saw the image in the stuff Penny had sent to me years ago, which I found yesterday, that I realized that something was wrong. Swapping my "right" speaker to the left side, and the "left" one to the right fixed everything. What an amazing difference! All of a sudden all of the detail that was missing was fully there. These speakers are truly amazing.

These speakers appear to be completely stock and do not appear to have been messed with. They have never been re-grilled so it's my guess that the labels were reversed when they were built at the factory. That is probably why someone had messed with the Cal resistors trying to improve the sound. It boggles my mind to think of the amount of music previous owners heard over the years and what they missed out on.

I still can't believe I came across that stuff from Penny. I could have been on a wild goose chase for months!

Thanks to all of you for your help in trying to get to the bottom of the issues I was having. And I'm sorry for having gotten you all involved in a wild goose chase.
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