That's why I suggested a sketch and labels. Some Ohm Meters have issues when the resistance values are just a few Ohms or less. And, if you place an Ohm Meter across an inductor or capacitor, you can also be fooled. My idea is to get zero Ohms from one side of a resistor to one wire or other component; repeat over and over until both sides of all resistors are accounted for. Then you can make a point to point wiring diagram or sketch. From there, you can then draw out the full X/O schematic.
You are all going too fast here, my friends.
I think I have figured it out right just by looking and doing a left to right mental flip:
https://www.diyaudio.com/forums/multi-way/363283-quick-win-tweeters-quiet-4.html#post6420356
I am quite good at this sort of thing.
I think I have figured it out right just by looking and doing a left to right mental flip:
https://www.diyaudio.com/forums/multi-way/363283-quick-win-tweeters-quiet-4.html#post6420356
I am quite good at this sort of thing.
clever Sys7.... 
. Me doesn't want to make effort if the op doesn't make the minimal effort to draw it for us ! (too much delay between right and left sides of my "brain" (or "resonant box with ears vented ports" whatever you call it) !
I believed there was a C//R that padded down the high end of the tweet... so I'm very bad at guessing shematic from pictures... and I played a lot with lego younger till last month !
. Me doesn't want to make effort if the op doesn't make the minimal effort to draw it for us ! (too much delay between right and left sides of my "brain" (or "resonant box with ears vented ports" whatever you call it) !I believed there was a C//R that padded down the high end of the tweet... so I'm very bad at guessing shematic from pictures... and I played a lot with lego younger till last month !
We gotta be fair. Most people don't come from an engineering background. I knew little about speakers when I first rocked up here but do have an engineering background. Which led to many interesting failures and much smoke being let out at first.
My speakers were broken for sure. But it became a growth or learning experience for me. For the interested student, a dome mid is quite a tricky thing:
SP38/13
My last thought is the pink NPE capacitors are failing. Time will tell.
My speakers were broken for sure. But it became a growth or learning experience for me. For the interested student, a dome mid is quite a tricky thing:
SP38/13
My last thought is the pink NPE capacitors are failing. Time will tell.
I have no technical background... but I know how to draw something simple by folowing lines points to points .
Sure from experience, the op should first swap the lytics by fresh ones as said very earlier the experienced members (explanation: inside resistance and capacitance values moves after one or two decades enough to change radically the loudspeaker). Only after investigate with the tweeter to know if ferrro fluided or not (it changes the low end that one may notice easier than the highs as we lost ears when agging ourselves).
Then investigate the filter drawing (change some values).
The violett has certainly its capacitance value marked on the body : the faster will be to swap it indeed with a cheap MKP à la Solen/Mundorf/etc. If too much soft, after changing the values of the filter, try to swap the serie resistor with the tweeter by a MOX. Then ask System 7 if it is not enough change (typically reduce a little the resistor value to make the treble more toppy/bright)
.Sure from experience, the op should first swap the lytics by fresh ones as said very earlier the experienced members (explanation: inside resistance and capacitance values moves after one or two decades enough to change radically the loudspeaker). Only after investigate with the tweeter to know if ferrro fluided or not (it changes the low end that one may notice easier than the highs as we lost ears when agging ourselves).
Then investigate the filter drawing (change some values).
The violett has certainly its capacitance value marked on the body : the faster will be to swap it indeed with a cheap MKP à la Solen/Mundorf/etc. If too much soft, after changing the values of the filter, try to swap the serie resistor with the tweeter by a MOX. Then ask System 7 if it is not enough change (typically reduce a little the resistor value to make the treble more toppy/bright)
Last edited:
high!
I think the key is R5 , it is in serial in the input of the LC filter (L4,C3) before the fuse and next the tweeter . This is a bit critical for the value because it can give unexpected result and create an uneven frequency curve .
It is actually 2,7 ohms i would try replace it with 2,2 , or solder 10 or 15 in // .
The strange things is that it seems that the cabling of the tweeter is rigid ,not a good idea . The fuse is also critical it must have excellent contacts and low internal resistance in order not taming the high frequency .
I think the key is R5 , it is in serial in the input of the LC filter (L4,C3) before the fuse and next the tweeter . This is a bit critical for the value because it can give unexpected result and create an uneven frequency curve .
It is actually 2,7 ohms i would try replace it with 2,2 , or solder 10 or 15 in // .
The strange things is that it seems that the cabling of the tweeter is rigid ,not a good idea . The fuse is also critical it must have excellent contacts and low internal resistance in order not taming the high frequency .
As said before, my thoughts, too. And I also don't have any engineering background. So I'm out here.
Best regards!
Thanks for this good advice.
Your idea about bypassing the resistor completely (short) make perfect sense to me - and I think is a great starting point.
By bypassing the resistor in question - and having a little listen at normal listening volumes (we rarely go above 90dB) - I should be able to determine: _
1. Am I working with the right resistor? (For the tweeter)
2. How does the tweeter sound with no attenuation?
Also, thanks for offering helpful info to this newbie - and not just trashing me for lacking the skill to provide a schematic of the crossover. Appreciated.
Just to be clear, the resistor that is in series with the driver goes to zero Ohms (just short circuit it with an alligator clip lead). The resistor across (parallel) the driver must be open (just lift one lead). If you search online, you can read about SPL (sound pressure level). If you can raise the level by 3 dB; you may have reached your goal. If you think of power only, 2 Watts is 3 dB more than 1 Watt. 20 Watts is 3 dB more than 10 Watts. As long as you still have a crossover capacitor, inductor, etc. BEFORE the tweeter; the risk of damage is fairly low BUT, start out with a lower than normal volume control setting TO BE SAFE!!!
Thanks for these thoughts, Simplex2.
Your post is very encouraging because I had already done the math and placed a 10-Ohm resistor in parallel to R5, before reading your post - which I estimated will give R5 a new TR of 2.13-Ohms. So, it seems we are thinking the same way.
In the interim, what I did find interesting is that when I measured the existing R5 [ specified at 2.7-Ohm/5W] it actually measures 2.1-Ohms!!!
That was a surprise.
I'm thinking that this means that R5 will probably need to drop down to around 1.5-Ohms TR in order to deliver a meaningful tweeter volume increase.
If this is true, the good news is that I just happen to have a pair of brand-new, very high-quality 1.2-Ohm/7W resistors in my spares pile - so they might provide the final R5 solution, for both speakers.
Before making any changes, I have decided to take oldspkrguy's great suggestion below. That is: I'm going to back-track a bit and try shorting R5 altogether first.
As below, after a listen at normal listening volume, this will help me determine: -
1. Am I working with the right resistor? (For the tweeter)
2. How does the tweeter sound with no attenuation?
I'm hoping this gives me a bit of an instinctive feel for where I need the tweeter volume to be - and will also reveal if the louder tweeter is messing badly with any of the other original crossover goals.
Thank you too, for offering helpful info to this newbie - and not just trashing me for lacking the skill to provide a schematic of the crossover. Appreciated.
Now I just need to wait for our 2-year old daughter to wake up, before I give the speaker another listen - with R5 shorted...
Exciting!
We gotta be fair. Most people don't come from an engineering background. I knew little about speakers when I first rocked up here but do have an engineering background. Which led to many interesting failures and much smoke being let out at first.
My speakers were broken for sure. But it became a growth or learning experience for me. For the interested student, a dome mid is quite a tricky thing:
SP38/13
My last thought is the pink NPE capacitors are failing. Time will tell.
Thanks for this support, System7.
You have done a ton of work for me here (below) and I appreciate it.
I am continuing to read it over and over to try and digest it; and learn more.
A quick trawl through DIYaudio shows that you are one of the most generous contributors here, so my hat is off to you.
Just to confirm, earlier in the thread I mentioned that I removed and tested all of the caps in the crossover(s). They all measured perfectly with my ESR meter, very low ESR and exhibited next to no loss.
That said - and mentioned earlier - I have already replaced C3 [Specified at 3.9-Ohms - you were VERY close!] positions on both speaker crossovers with high-quality polypropylene caps. This did not increase the volume of the tweeter at all. In fact, I felt that the tweeter was even quieter than before, after the change.
Once again, thanks for going easy on me and not dissing me for my current lack of know-how. Appreciated.
How hard can it be?
The L4 0.3mH coil bottom left is the right size for a tweeter section. The small pink C3 capacitor makes sense too and ought to be around 3.3uF. R5 2R7 must be the level adjust.
So you just reduce the 2.7R to, say, 1R for 1.5dB more loudness. Or short it out altogether as an experiment.
Ferrofluid is a possible culprit. I've taken it out of my tweeters with blotting paper. Sound better:
And as an afterthought, it might be worth cleaning the tweeter fuses if you haven't already. They can corrode.
And here is the same conclusion right there in System7's previous post.
Looks like I am finally on-track here.
Our 2-year old is awake now, so listening with R5 shorted, about to commence!
(By the way, the fuses are pristine. No problems there...)
LISTENING TEST 1 COMPLETED! [Shorted Tweeter Resistor]
As most of you probably predicted, there was just too much tweeter volume - which sounded fantastic and VERY extended! - but the midrange and bass drivers barely got out of bed.
So not quite right.
Through this test, the tweeter cap [C3] remained in-circuit, protecting the tweeter from the low frequencies.
So, to my thinking, this confirms the following: -
1. We picked the right resistor to short [R5] for the test.
2. The new polypropylene C3 caps are performing well.
3. The original crossover attenuated the tweeter - with 2.1-Ohms of R as measured - for good reasons. But I just want them a shade louder.
I'm thinking to install fresh new resistors at around 1.5-Ohms. I will stay with 5W power handling, as per original specification.
I will probably order-in the parts locally, so the quality remains high.
I will report back...
As most of you probably predicted, there was just too much tweeter volume - which sounded fantastic and VERY extended! - but the midrange and bass drivers barely got out of bed.
So not quite right.
Through this test, the tweeter cap [C3] remained in-circuit, protecting the tweeter from the low frequencies.
So, to my thinking, this confirms the following: -
1. We picked the right resistor to short [R5] for the test.
2. The new polypropylene C3 caps are performing well.
3. The original crossover attenuated the tweeter - with 2.1-Ohms of R as measured - for good reasons. But I just want them a shade louder.
I'm thinking to install fresh new resistors at around 1.5-Ohms. I will stay with 5W power handling, as per original specification.
I will probably order-in the parts locally, so the quality remains high.
I will report back...
RESISTANCE: The resistance of a fuse is usually an insignificant part of the total circuit resistance. Since the resistance of fractional amperage fuses can be several ohms, this fact should be considered when using them in low-voltage circuits. Actual values can be obtained by contacting Littelfuse. Most fuses are manufactured from materials which have positive temperature coefficients, and, therefore, it is common to refer to cold resistance and hot resistance (voltage drop at rated current), with actual operation being somewhere in between. Cold resistance is the resistance obtained using a measuring current of no more than 10% of the fuse’s nominal rated current. Values shown in this publication for cold resistance are nominal and representative. The factory should be consulted if this parameter is critical to the design analysis. Hot resistance is the resistance calculated from the stabilized voltage drop across the fuse, with current equal to the nominal rated current flowing through it. Resistance data on all Littelfuse products are available on request. Fuses can be supplied to specified controlled resistance tolerances at additional cost.
I found this about fuses from the brand "Littlefuse"
If you are satisfied with the sound after getting the resistor value figured out; probably best to stick with the original fuse type. I was thinking maybe you had some super cheap type fuse that could significantly affect sound quality.
Of course, if you used a higher amperage fuse, the resistance would be less but then you might run the risk of blowing a tweeter instead of a fuse! There is an old Murphy's Law joke about a $20 transistor blowing first to protect a 20 cent fuse!
Just make sure the the fuse holder contacts make a nice, tight squeeze against the fuse contacts, you could also spray the contacts with CAIG "DeOxIT". This stuff is expensive but works really well at restoring old electrical contacts.
DeoxIT(R) D5S-6, More than a Contact Cleaner
Fuses - Types of Fuses - Littelfuse
I found this about fuses from the brand "Littlefuse"
If you are satisfied with the sound after getting the resistor value figured out; probably best to stick with the original fuse type. I was thinking maybe you had some super cheap type fuse that could significantly affect sound quality.
Of course, if you used a higher amperage fuse, the resistance would be less but then you might run the risk of blowing a tweeter instead of a fuse! There is an old Murphy's Law joke about a $20 transistor blowing first to protect a 20 cent fuse!
Just make sure the the fuse holder contacts make a nice, tight squeeze against the fuse contacts, you could also spray the contacts with CAIG "DeOxIT". This stuff is expensive but works really well at restoring old electrical contacts.
DeoxIT(R) D5S-6, More than a Contact Cleaner
Fuses - Types of Fuses - Littelfuse
Very true; however, in this case I think it comes down to personal listening choice as opposed to an exact level match. In my case; I do the same thing with my tweeter level, I adjust it to my liking (I am in my mid 60's so every dB above 10 KHz is a bonus for me! ha ha). [I have separate amps for each driver pair so I can very easily adjust levels (mostly passive crossovers)].
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.