As an undergrad life started at sunset, I was on a first name basis with many of the facilities crew and campus police more so than the faculty.
The sweetheart of a Guatemalan janitor, Cynthia, in grad school was patient (even relished) with me trying to communicate with her in Spanish. Definitely one of my favorite people.
As others have stated, DF is a ratio of amp to vc resistance. A higher DF means more control. A speaker may be designed with a Q of .7071, meaning it is designed to not overshoot...DF with that is different than say a fourth order cab. The experts here can talk better on those trade offs.
As you appear to be doing, playing with values to get the sound you like is a good thing. I am inclined to do the same. What I like is my concern.
I will say, I prefer tight boxes and horns which do not rely on energy storage to develop response. But, that is me.. Others are different.
Jn
"Campus police"???
Don't tell me you were a bad boy?
Jn
No, I had to hire them to escort the box office receipts from our film society to the safe. I got to know a bunch of them, I'm just a blue collar working stiff at heart.
Darn. I was hoping I knew a bad boy..
I was a nerd and athlete, so my undergrad life was put to sleep boring.
..btw, you were correct. Joe's best path is to ignore me.
Jn
I was a nerd and athlete, so my undergrad life was put to sleep boring.
..btw, you were correct. Joe's best path is to ignore me.
Jn
Got that covered
Needed the instructor to look the other way to pass the swimming test.
Swimming test???
You had a course in swimming???
Thankfully, I did not have that..
Jn
No, it was one of those huge donors who's son drowned so he stipulated that every student had to do 4 laps of an Olympic pool to graduate for his millions to go in the till.
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Not a bad idea IMO.
I used to do a mile a day at lunch in the pool here. Stopped when I got sick of head on collisions with some who could not stay in their lane. I must admit, counting to 54 was the most boring thing I can think of...pool is 100 foot. On the plus side, I learned how to flip at the ends. For some reason, putting that on my resume doesn't seem to impress anybody...go figure..
Jn
I used to do a mile a day at lunch in the pool here. Stopped when I got sick of head on collisions with some who could not stay in their lane. I must admit, counting to 54 was the most boring thing I can think of...pool is 100 foot. On the plus side, I learned how to flip at the ends. For some reason, putting that on my resume doesn't seem to impress anybody...go figure..
Jn
I hope you are not trolling because this will raise the usual sh*t storm....so here goes. I have experimented with numerous lead containing solders including Multicore 60Tin/40Lead, Multicore 63Tin/37Lead, Multicore Savbit (60Tin/38Lead/2Copper) and Multicore LMP (62Tin/38Lead/2Silver) and concluded that lead is not to my liking with Savbit sounding least bad and LMP sounding drive you out of the room bad.......ie IMO lead and silver don't go together at all. I use lead free exclusively nowadays and find that I much prefer it to any of the lead containing alloys.
I currently use this 99.3Tin/0.7Copper alloy because it is easily available locally, I reckon it sounds good* and it does solder perfectly nicely when you get the hang of it. I have also used Multicore 96S (96.3Tin/3.7Silver) long ago and from memory found it to sound really good but I need to revisit it again knowing what I now know....it's also expensive. There are some other Multicore lead free solder alloys that I have not tried - View attachment solderwireproperties.pdf
In answer to your question I find that swapping out the 'who knows what/Hu flung dung' solder at the driver terminal/flex lead joints with the above lead free solder makes a very agreeable improvement in clarity intelligibility and musicality and it follows that all connections to all the drivers should be the same solder, ditto all input and crossover joints with the joints nearest to the final transducer voice coils having the greatest change/benefit ie flex lead joints and signal wire/RC-RLC network connections. Ensuring that all loudspeaker joints and all driver joints are the same solder alloy also sets a 'coherence' in the overall sound and this is critically important IMO......this is a low cost experiment to try and will beneficially change the sound of your speakers IME/IMO.
sounds good* - I find lead puts a bumpiness/lumpiness in the bass/vocals and overall 'wrongly damped' and unintelligible character in the sound, lead+ silver does the same buts adds a hard/bright sheen that does not belong (a false/wrong brightness/detail that grates in time IMO). The Tin/Cu perhaps initially might sound slightly dull but no nasties (errors of omission perhaps but no embellishments) in comparison and long term I find it to be pleasing/pleasant and more naturally detailed and totally preferable to any of the lead alloys I have heard. I find the same deal with RCA interconnects and I find some retail 'high quality' interconnects I have containing various lead alloys are unlistenable now that I know the difference. George, you asked so there is my answer from careful experimenting and long experience, YMMV and to those who will have you believe that solder alloys cannot have subjective effect my reply is simply to try the experiment.
Cheers.
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Hi Dan,
Too bad most products were soldered with Kester '44, lead-tin combination. Everything must sound lumpy and bumpy. Even the Multicore solders (excellent) and others have been used everywhere from the mics and pickup coils, through the recording desks, tape machines (or computers) and onto the media making equipment are lead based solder. The new formulations don't all use silver, lead-free solder is already too high in temperature.
Guess what happens when you solder the flexible leads in drivers? The new, and old solders "wick" up that lead making the first part solid. It's a good way to hasten lead failures. So I would ask you to use extreme caution when recommending some procedures to other folks. If you like to do it and wreck your own woofers - okay. Just don't take others with you.
In case you're wondering, I administered loudspeaker warranty programs and did incoming inspection on re-coned drivers. Never, ever apply heat or new solder to the flex leads going from a speaker terminal where the wire leads to the cone.
Now, on to solder affecting a signal in any way. I'd like to point out that test equipment which is far more accurate and lower noise than audio equipment seems to survive any reasonable solder used in connections of their boards. This equipment is sometimes extremely sensitive to amplitude and phase problems and operate over the frequency ranges from DC to literally light. I have yet to see any equipment that used silver solder (some specific sensors do). I am dying to see an instrument that says on the case something like "wired with Monster wire" as some audio gear was.
-Chris
Too bad most products were soldered with Kester '44, lead-tin combination. Everything must sound lumpy and bumpy. Even the Multicore solders (excellent) and others have been used everywhere from the mics and pickup coils, through the recording desks, tape machines (or computers) and onto the media making equipment are lead based solder. The new formulations don't all use silver, lead-free solder is already too high in temperature.
Guess what happens when you solder the flexible leads in drivers? The new, and old solders "wick" up that lead making the first part solid. It's a good way to hasten lead failures. So I would ask you to use extreme caution when recommending some procedures to other folks. If you like to do it and wreck your own woofers - okay. Just don't take others with you.
In case you're wondering, I administered loudspeaker warranty programs and did incoming inspection on re-coned drivers. Never, ever apply heat or new solder to the flex leads going from a speaker terminal where the wire leads to the cone.
Now, on to solder affecting a signal in any way. I'd like to point out that test equipment which is far more accurate and lower noise than audio equipment seems to survive any reasonable solder used in connections of their boards. This equipment is sometimes extremely sensitive to amplitude and phase problems and operate over the frequency ranges from DC to literally light. I have yet to see any equipment that used silver solder (some specific sensors do). I am dying to see an instrument that says on the case something like "wired with Monster wire" as some audio gear was.
-Chris
Can you post schematic or that pic again please. One further musing, I think you have way overcompensated the tweeter and changed the 12db filter alignment drastically causing peaking and premature roll off ....tweeters have low inductance so don't need much C in the parallel RC network.
The main inductance to cancel is the woofer and is probably something like 3mH or so for old school 12", specs or measurement will tell the value. Compensating directly across the woofer will change the woofer LPF FR in addition to providing local electrical damping so will change sound on two fronts with crossover to driver connection loop area (inductance) an additional impediment.
If you put the RC network across the loudspeaker input you are providing an accumulator/water hammer stopper to use hydraulics analogy and freeing the amp from continually adjusting it's output current to matching current demands of the driver according to the suspension stictions/non linearities/inductance/microphonics that control back emf....the amp sees only a clean resistive load which means that it is not dealing with electrically erratic/noisy load and inductively stored return energy. As Pavel, Scott etc point out this 'noisy load' should be of no consequence for a 'perfect' audiophile high bandwidth/low output resistance amplifier but for mid-fi gear this cable/loudspeaker interaction can be problematic IME and causes 'hashy' sound.
Perhaps a combination of woofer under compensated LC and balance of compensation at the crossover input terminals is worth the experiment ?.
Firstly, doing this isn't productive. The RC has been designed to work with a certain impedance to give a certain result. Anywhere else is bound to show a different impedance and have different priorities.
If your amplifier is a Voltage source, and you connect the RC before the crossover, the RC should not affect the crossover because the amp presents each of them the same voltage. If anything, the amp will still need to feed it with current. Were the values of R and C interesting?
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In this issue Joe is more correct.jneutron said:
Whether a driver can be regarded as a current or voltage device depends totally on frequency. For most part of the operation band of a typical direct radiation driver, it is current that determines the output.
Only in the fundamental resonance region the motional EMF is great enough and in such phase that it gets dominion over the resistive voltage component and produces the partial velocity feedback effect that could justify the expression 'voltage driven device'.
When going above 2-3 fs or so, the back-EMF soon becomes smaller than the resistive voltage drop and also turns into phase quadrature with it and in addition becomes masked by inductance, so that any voltage control effects vanish, and all control is handed over to current through the Bli force.
So, the determining factor is which is greater: Blv or Ri.
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Simplifying down will be the death of both of us. Too much is going on, so both yours and my explanation are insufficient. My explanation is accurate in all cases at all frequencies, you are simply parsing out regions where you have decided "dominion". As an engineer, we can select regions where different methodologies will reduce error, this is one of them.
At higher f with low emf, the simple LR circuit can still be considered a linear voltage driven circuit, and we can simply calc amplitude and phase of response.
As I said, it is the current doing the work. But the driver is in essence a voltage driven device, the emf is the physical reaction effect, the current is the pusher to minimize the error.
This can easily be considered a PID loop, with the V/EMF difference as the following error, the gain being the current /error.
I know your. "Hammer" is current drive, so everything you look at is a nail... And I respect that, current drive can fix some nonlinearities v drive cannot. Did you follow my cowound coil discussion a while ago? If so, would you like to get involved in some R and D?
Jn
At higher f with low emf, the simple LR circuit can still be considered a linear voltage driven circuit, and we can simply calc amplitude and phase of response.
As I said, it is the current doing the work. But the driver is in essence a voltage driven device, the emf is the physical reaction effect, the current is the pusher to minimize the error.
This can easily be considered a PID loop, with the V/EMF difference as the following error, the gain being the current /error.
I know your. "Hammer" is current drive, so everything you look at is a nail... And I respect that, current drive can fix some nonlinearities v drive cannot. Did you follow my cowound coil discussion a while ago? If so, would you like to get involved in some R and D?
Jn
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If your gonna do bassackwards like me make sure you tune from the lp with several hq recordings that you know well......find a reference volume level to compare all your changes. (Digital volume control helps that, 0db is mine)
One of my favorites are crites modded k-horns.
I’ve always preferred sealed bass enclosures my next sub enclosures (lab 15’s/crown 2002) are Experimenting with aperiodic (leaky) boxes.
Hey Dan,
It’s a 6db on the tweet (series 10uf bypassed with a 0.10uf,
Boucherot when moved after xo/before tweet ended up 4ohm/0.47uf, still peaks but not as bad.
Bass/mid driver is Dayton pa255-8....stated inductance is 1.49mh
When it was before the xo it was 6ohm/0.47uf
My sound at the moment is quite good, this was more experimentation......what it does best is focus/fix the combing issues I got with my new dual tweeter testing. But the trade off (unless I can get it dialed better) is not worth it imo.
I will continue with it as it’s cheap and easy to mess with but it’s not really ‘needed’ I don’t believe.
The education is productive enough......interesting in the fact I figured out you needed to match the impedance and r And I think the 0.47uf is too high.
I’m using mills resistors and jantzen superior z’s so parts quality is not a question.
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Hi Bob,
The economics just don't make sense here to run even all the audiophile type capacitors
-Chris
The parts you are using are only audiophile approved, which has no bearing on quality. The Mills resistors aren't bad, but I have had to replace them before. The capacitors leave a question mark for me since you could get identical performance with parts used in industry. The machines they are wound on are there for industrial quantity production. The Audiophile community would never pay for these machines, not even used ones. You just couldn't operate the machines enough to break even. It wouldn't surprise me to see that one manufacturer is producing competing product lines.
The economics just don't make sense here to run even all the audiophile type capacitors
-Chris
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