Design calls for .7mh, is .68 OK?

[Audiophilenoob]

Forget the tolerance and the E=mc^2, I guess my message didn't delivered.

6.5uF + 100nF + 100nF, that's about 6.7uF. Find a proven design and add a 100n to any 6.5uF in the network, listen and go back after a month. Capacitors (or the join?) need to 'burn-in'. Wait, I hear you laughing. You need more time to perceive the change in capacitance than in inductance.

If you are close, I would be very very happy to accept the $500 challenge. But of course, I should have the right to choose or to create the crossover network (and the drivers too!). This is where the 'critical' word plays its role!

I was describing the infinite problems with passive parallel networks (not so good example tho) was to explain that you cannot just plug any components and there you have a good speaker.

please stop while you have some credibility left

burn in eh???

ever see all those crazy burn in abx tests ???

lol

going from a .2mh to .3mh inductor can make audible differences

I'm simply referring to generally very small percentage differences

if you were close I would set up the ABX... but you'd need to buy me some grey goose if you lose

I've had more than one conversation with two very very very intelligent amplifier troubleshooters and EE's about burn in, caps, etc etc

lets just say that the science doesn't support your "burnt in ears"

 

[sberube]

I know what you mean Jay and you're right, I do check to see what the rounded up values will do to the xo point and where they will put me. In this case the P13 and matching tweet will be fine and we've got nothing to worry about.


Still, how does one 'bypass' these components (inductors and caps)? Anyone? Anyone? bueler....

cap cascade...
C1
/ \
----C2----
\ /
c3

inductor bypass
I1
/ \
---/ \----
\R1/


Does that make sens to you? (sorry, my ascii art is rusty)

 

[sberube]

Darn, that's all wrong... sorry, the spaces don't show up properly. For a cap cascade (or bypass) just put together the caps (all values need to be added to get total value) and stick your heading leads together and your trailling leads together.

As for bypassing an inductor, just use both of your inductor's leads and join each of them to each side of a resistor's leads. (like sticking a resistor in between to short the inductor).

cap cascade...
C1
/ \
----C2----
\ /
c3

inductor bypass
I1
/ \
---/ \----
\R1/


Does that make sens to you? (sorry, my ascii art is rusty)

 

[Bose(o)]

Right, so the bypass resistor and caps would be in parallel with w/e you are bypassing, correct?

I'll definitely give this a try, but wouldn't the resistor then be in sereis with the speaker and thus increasing the DC resistance presented to the amplifier?

 

[Salas]

you've got to be joking

No I am not joking. These are bonafide findings I share here.

I do measure my coils with a digital impedance tracer since you mention tolerances.

But every coil that I ever bought for being nominally smaller by .2 mH was not everytime spot on but always smaller than the near nominal value one from the same supplier.

As for 'magic' I am using that word to differentiate from the quantitative realm which is certainly no big deal in this case.

But when listening critically, yes, a piano can become dull or grab your attention for little changes in a crossover. 'Magic' is in the details. Every one seeking to please the senses knows that.

Acclaimed speaker manufacturers boast tolerance matching (with files kept for servicing) since the early 70s.

 

[Jay]

Originally posted by Audiophilenoob
please stop while you have some credibility left

Don't worry, I'm not looking for some credibility here...
I'm trying to fill the missing pieces... To complement the intelectual
thoughts from you engineers

Originally posted by Audiophilenoob
burn in eh??? ever see all those crazy burn in abx tests ??? lol

Yeah, there's a flaw in the test itself. The test can be used to prove
that 2 things are different, but it cannot be used to prove that 2
things are equal. This might explain:

If you have a speaker with 5.6uF (better if the speaker is flawed) then
do an ABX test with 6.6uF. There would be many who wouldn't be able to
differentiate, but you do know that they are different. It is NOT easy
to detect those changes. And, it is even difficult to know if we really
like what we think we like!

I can decide on spot if I need to lower or increase an inductance. But
I sometimes need one day to decide if I need to change a capacitance.
You're right, those guys are crazy. I have met some who claimed
themselves golden eared audiophiles with 20 to 30 years of experience
but I happend to be able to detect what they couldn't.

Once, in his showroom a man presented me with his speaker design. I sat
on a special listening chair. When I moved my head to the right or to
the left, 'something' changed. Isn't that crazy We changed the
amps, the speakers, until I told him that I hear something terrible.
He said he didn't hear anything until I tried to find the problem by
myself. No need to tell you what I found. Surprised me he couldn't
hear such terrible sound

Once, in his audio workshop a man presented some audience with his
system. He drove the speaker so hard so I thought it was funny that I
couldn't hear tweeter resonance (it was 3-way), so I tried to examine
closely and told the man that the tweeter didn't produce any sound.
It took a long time to convinced him and took the tweeter out.

Originally posted by Audiophilenoob
going from a .2mh to .3mh inductor can make audible differences
I'm simply referring to generally very small percentage differences

You're right. 0.2 to 0.3 is 50% increase. But if you put this inductor
in parallel with 0.5 ohm resistor, you may not find audible difference.

Let see a small value inductor in paralel with tweeter. People usually
use 0.2 or something. Rarely it is 0.217 or 0.178. While in fact the
difference in percentage is not small, and the effect to the sound is
real! Okay, if you lower the inductance then you may free the tweeter
from resonance. If with 0.2 you definetely can't hear resonance, then
by lowering to 0.195 you may not hear audible difference. But I often
found a situation where the best inductance is the one close to value
where resonance occurs. If you lower the inductance you will lose the
'magic' and if you increase you will face the resonance.

Now let's see at begineers' speaker designed with not-so-advance tools.
You may find a big sag in SPL response at crossover region. This is
because it is difficult to correctly link the tweeter with the woofer
so they choose to roll-off the tweeter so high. With this situation,
if you increase the tweeter roll-off a bit (by decreasing capacitance
a bit) you may not hear audible difference, because the tweeter is in
not-so-critical 'save' condition.

Originally posted by Audiophilenoob
I've had more than one conversation with two very very very intelligent amplifier troubleshooters and EE's about burn in, caps, etc etc
lets just say that the science doesn't support your "burnt in ears"

You're right. That's why I'm interested in voicing my opinion, because
the very intelligent amplifier troubleshhoters and EEs as well as science
'does not' support it

 

[rcw]

re components

A point that should be made about crossover components is that real values that work best are often twice or half the theoretical values originally calculated, if you are building a already designed crossover and using it with the recomended drivers then no component needs to be closer than 5%.

 

[Jay]

Re: re components

A point that should be made about crossover components is that real values that work best are often twice or half the theoretical values originally calculated.

I noticed a 'similar' phenomenon. But which component? In third order tweeter filter, the smallest capacitor usually determines the crossover point or where the roll-off starts. This is more critical than the other 2 components shaping the roll-off.

 

[Jay]

Effect of first capacitor in third order highpass filter

This morning I designed a 3rd order crossover using a notch filter for my Dynaudio D21/2. Like always, I rely on my golden ears (huehehe ). I don't trust formulas, and I don't have the tools to measure the tweeter (even the must-have LCR-meter ), except for the information I found on the net covering the Fs of 1300, Z of 6, Re of 5.2 and a sensitivity of something.

Okay, I trust formulas a bit, so I use the basic formulas for impedance, and use 5.2 as a 'design' impedance to predict the location of tweeter resonance for the notch. Of course, I need the formula just to help me locate the starting trial CL values. The rest is on my ears (Can you imagine what speaker this going to turn out to be if I'm deaf )

So, for a few days I'm going to listen to this filter. Not perfect but listenable...
R input = 6.8 ohm
3rd filter C1/C2/L = 5.27uF / 11.7uF / 0.23mH
Notch C/L/R = 28.42uF / 0.36mH / 2.5ohm
The inductance is approximation (but close!) as I unwind inductors without LCR meter.

You may ask, why is this 6.8 ohm located before the filter? That's art. That's the benefit of not having the necessary tools for speaker design , so I don't care how to calculate the real impedance, or the rate of the sensitivity padding (to meet that of the woofer). Whether it is equivalent to put this R before or after the filter, I don't care, as the major purpose of the R is to create a notch/zobel related to the woofer.

So now I want to elaborate the effect of changes to a few components on the above network.

C1 (5.27uF) is the first filter determining the roll-off. C1 should 'lock' the woofer, with phase issue as the major problem (I'm not sure if what I usually hear is phase, it's just it).

Just about it's highest value, C1 changes (increase/decrease) can be easily heard with woofer on. Decreasing C1 (a bit! about 100n) will create a 'gap', or 'disconnection' with the woofer. Increasing C1 (a bit! about 100n) will create an 'overlap' which will be more audible when there's a phase issue. The common effect is loss of sonic and no enjoyment to music. If this C1 is too small than what it has to be, 100n difference may be in-audible.

L (0.23mH?) is the inductor parallel with the tweeter. Usually I unwind inductor and design for only one channel. For the other channel, I tried to unwind second inductor such that they will have equal winding (except when LCR meter is available). Trust me, with similar winding they always sound different!

Now the most laughable thing to explain...

Cn (28.42uF) is the capacitance determining the lowest frequency of the signal to be padded in the notch filter. I could hear the effect of an increase of 0.081uF and a decrease of 0.0899uF! How come??? Well, it depends on the critical instrument sound just about that frequency, or the critical resonance just about that corner. This notch filter might only cut half of the bump toward the higher end, leaving another 'minor' bump. Flat response and impedance is never my objective anyway...

There is one thing, my opinion about modern or conventional speaker design (the non-artistic, scientific approach). People may rely on softwares and tools (sometimes use them without knowing how these tools are designed) and build a speaker without experiencing listening practice. Some use softwares and happen to realize that the result is crrap. Some then happen to conclude that passive parallel crossover is inferior to the series crossover. Some then happen to always go with active crossover.

Take one woofer and cross it at normal frequency with 3rd or 4th order parallel filter. Cross at frequency where impedance is flat and there's no resonance. Choose any type of roll-off (shallow/steep, high Q/low Q) and listen. Do they sound the same? No. Certain roll-off shape can make the music float. Which parameter to be used to choose the right one? Can Calsod explain this?

I may be unknowledgeable and my ears may not be made of gold. But I have lots of listening experience and a waste of time

 

[Magura]

Hmm Jay, your post could have been written by me a couple of years ago. I still agree to quite an extend though. To make a XO sure is half art, half math. I have seen quite a number of people getting themselves into trouble with the 100% scientific way of doing things. When something sounds bad but measures good, they seem to get stuck in a dead end road, as they would have to actually listen their way through, they just continue with the measurements.

I like to support my listening experiences with measurements, but I listen first and tweak to what I like best, then I measure just to confirm that there is nothing exceptionally wrong with what I made. I have though had a case or two where I had to give up the tuning by ear approach and measure, just to get a hint about what had gone dead wrong.


Magura

 

[Audiophilenoob]

I like to support my listening experiences with measurements, but I listen first and tweak to what I like best,

why on earth would you go passive if this is the case?

 

[Magura]

why on earth would you go passive if this is the case?

You're hinting at something, but I can't figure what???

Magura

 

[Audiophilenoob]

You're hinting at something, but I can't figure what???

Magura

if you want to tweak and change to get ideal sound the only way to do that... is actively

not only that but generally a full on active system gives you far more control in every aspect

phase, xover points, slopes, DRC, and such.... I'm unsure why you would go passive period if you plan to change out several hundreds worth of parts until you find that "right" sound ... not to mention generally active just sounds cleaner

 

[Magura]

Well, I will have to confess that I am lazy, as in very lazy. I know how to deal with passive XO's and I have pretty much any passive XO component in stock that I could wish for.

On the contrary I have little or no clue about making active XO's, and no idea about how to deal with such, so I would never get anything up and running (in case somebody should feel adequately sorry for me to give me one).

I have considered to take the effort to figure how active XO's work for a couple of years, and if you meet me in 5 years, I'll probably still be "considering", unless somebody takes pitty on me and force feed me what I need to know

Magura

 

[K-amps]

why on earth would you go passive if this is the case?

Because he has already got a partially working passive unit, also he may not be comfy with actives lastly there is always the possibility that he may need another amplifier with Actives... just conjecture here...

 

[Magura]

Because he has already got a partially working passive unit, also he may not be comfy with actives lastly there is always the possibility that he may need another amplifier with Actives... just conjecture here...

Naah, it's just easier to be conservative


Magura

 

[Bose(o)]

I have seen quite a number of people getting themselves into trouble with the 100% scientific way of doing things. When something sounds bad but measures good, they seem to get stuck in a dead end road, as they would have to actually listen their way through, they just continue with the measurements.


Magura

And which proves, loosely, that the measurements that occur are inaccurate and don't caputer the entire picture. Ergo, frequency response, phase response, etc. are inaccurate, at least on their own.

 

[Audiophilenoob]

And which proves, loosely, that the measurements that occur are inaccurate and don't caputer the entire picture. Ergo, frequency response, phase response, etc. are inaccurate, at least on their own.

why exactly wouldn't manually adjusting this actively be completely better in every way? not to mention the major advantages to a full on DRC

 

[Jay]

why on earth would you go passive if this is the case?

I believe we DIYers have plenty of amplifiers. But don't forget the artistic aspect of this DIY. Many of us always want something simple, small, but SOUND GREAT!

To magura who doesn't know about active , Audiphilenoob was right that active doesn't have those problems with passive. IMO, the most important problems are phase, sharing of voltage, and that high-pass filter is alway affected by lowpass filter (and vice versa). BUT...

If you don't know about active (just like me), you can use BIAMPING! Being experienced with building by ears (referring to my procedure to come to the final x-over), I know that once I can find a high pass filter that sounds good (without the woofer), and another good sounding lowpass filter, I can join them easily with biamping. With convensional x-over this often impossible, because we have to compromise putting one driver not in it's best condition in order to get a 'locking' between 2 drivers, which is more important.

The result of x-over designed this way on biamping is similar to what Audiophilenoob said about active: generally clean. I often surprised how enjoyable a biamping crossover can be! But I'll go the purist way. Otherwise, I'll buy the most expensive amp/speaker I could buy, build the best DIY amplifier, build the best DIY speaker, and stop building anything

 

[Audiophilenoob]

I believe we DIYers have plenty of amplifiers. But don't forget the artistic aspect of this DIY. Many of us always want something simple, small, but SOUND GREAT!

To magura who doesn't know about active , Audiphilenoob was right that active doesn't have those problems with passive. IMO, the most important problems are phase, sharing of voltage, and that high-pass filter is alway affected by lowpass filter (and vice versa). BUT...

If you don't know about active (just like me), you can use BIAMPING! Being experienced with building by ears (referring to my procedure to come to the final x-over), I know that once I can find a high pass filter that sounds good (without the woofer), and another good sounding lowpass filter, I can join them easily with biamping. With convensional x-over this often impossible, because we have to compromise putting one driver not in it's best condition in order to get a 'locking' between 2 drivers, which is more important.

The result of x-over designed this way on biamping is similar to what Audiophilenoob said about active: generally clean. I often surprised how enjoyable a biamping crossover can be! But I'll go the purist way. Otherwise, I'll buy the most expensive amp/speaker I could buy, build the best DIY amplifier, build the best DIY speaker, and stop building anything

how about design the best active xover, build the best possible speaker for any amount of money, build crazy SS amps, and be content

that's where I'm at now