I had to edit my above post, so check it out again.
Bottom line is, if the replacement 16 ohm woofer sounds OK with the present iron-core inductor then there is no need to increase its value. You would only need to do so if the midrange had proved too bright. Your son seems to like the midrange presentation that has resulted from the woofer swap, saying it is "clearer" than that produced by the enclosure containing the original, working mid/bass driver.
You appear to have struck it lucky and give no overwhelming reason for having to alter the values of the crossover components. Increasing the value of the iron-core inductor would reduce the level of the midrange frequencies and your son may no longer come to the same conclusion!
Bottom line is, if the replacement 16 ohm woofer sounds OK with the present iron-core inductor then there is no need to increase its value. You would only need to do so if the midrange had proved too bright. Your son seems to like the midrange presentation that has resulted from the woofer swap, saying it is "clearer" than that produced by the enclosure containing the original, working mid/bass driver.
You appear to have struck it lucky and give no overwhelming reason for having to alter the values of the crossover components. Increasing the value of the iron-core inductor would reduce the level of the midrange frequencies and your son may no longer come to the same conclusion!
Thanks.
Good news then, & cheaper as well. 🙂
In my life I'm surrounded by things and situations requiring repair or resolution.
It's always nice to be able to reduce this list.
I'll fit the 4μF capacitors & retest.
Ditto my life!
Yours is a very simple crossover and one which will allow some leeway in component values, so no need to sweat over the exact millihenrys and microfarads.
However, when you get your LCR meter, I'd be interested in knowing the inductor values, just to see if they are anything like what I estimate they might be!
Yours is a very simple crossover and one which will allow some leeway in component values, so no need to sweat over the exact millihenrys and microfarads.
However, when you get your LCR meter, I'd be interested in knowing the inductor values, just to see if they are anything like what I estimate they might be!
Thanks Galu.
When the meter arrives I'll definitely be testing the iron core inductors regardless.
Always keen to improve sound reproduction economically.
I'll definitely be measuring both.
Finished to re fit to both boxes & fitted the new capacitors.
Played the speakers but not totally sure of the result.
Perhaps lacking in bass, & a little hissy on female vocals when singing words with "s".
Also the speakers seem a little unforgiving on some recordings.
I need to do a further listen on a different Amp, and a wider range of recordings.
If the electrolytic doesn't solve the sibilance problem, then you may have to increase the value of the inductor.
Here's a suggestion that will allow you to experiment before spending money on new inductors. Take the iron core inductor out of one cabinet and put it in series with the one in the other cabinet. Then see how the cabinet with the doubled up inductor sounds.
Here's a suggestion that will allow you to experiment before spending money on new inductors. Take the iron core inductor out of one cabinet and put it in series with the one in the other cabinet. Then see how the cabinet with the doubled up inductor sounds.
Thanks Galu.
At this stage I won't give up on the newly fitted caps.
I'm going to persist with them for a little while longer.
I need to play the tracks I had issue with on another rig to eliminate poor recording variables.
Also run in period if there is such a thing.
I don't want to blame the changes on poor recordings.
After that the Inductors in series is a great idea.
Before this, I'll perform measurements with the new tool when it arrives.
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I can tell you a story regarding the B&W DM 220's.
I have a pair of B&W DM 110's which you helped me reconfigure.
We put effort into upgrading the XO's, but on completion I discovered the tweeters were cactus.
A couple of months later, I noticed a pair of speakers in a pile of hard rubbish placed on the kerb.
I immediately thought, what was the probability of finding a pair of B&W DM 220's.
The boxes weren't in good condition, but the 4 woofers & 2 tweeters turned out to be fully functional and cosmetically in good condition.
The tweeters were harvested to save the DM110's, a pair of the Woofers were shipped to Sydney to save another pair of speakers there, and now, the last pair of woofers have been used to save the Rotels.
I love salvaging and repurposing, and saving.
Much effort, energy & expense went into manufacturing these things, and in many respects, can match or even better some of the rubbish being sold on the market today.
Naturally enthusiasts, such as yourself and other forum members, provide the necessary knowledge and expertise to make such things happen. 🙂
👍
I think I told you at the time that I was donated a pair of (brown) DM 110s. I've done no more than just take a look at the crossover inside one of the enclosures. They sound absolutely fine in the radio based system I use for background listening in my workshop.
In 1985 the DM 110s achieved 'Best Buy' status in a 'Hi-Fi Choice' review. Despite their budget price of £129, they scored above average in the company of all the speakers tested whose average price was double that of the B&W model.
So, you are correct, there's got to be life in some of those old timers yet! 🤓
In 1985 the DM 110s achieved 'Best Buy' status in a 'Hi-Fi Choice' review. Despite their budget price of £129, they scored above average in the company of all the speakers tested whose average price was double that of the B&W model.
So, you are correct, there's got to be life in some of those old timers yet! 🤓
Nice garage speakers.
I'm learning, often the retail price has often has no bearing on performance or quality.
You also indicated that DM110 Bass Drivers were wired to LF 2.5 mH iron core inductors
It'll be Interesting to see how far off the Rotel iron core inductors measure.
However, their 2.5 mH inductor is part of a 2nd order low-pass filter in conjuction with a 7 uF capacitor, so not directly comparable with your 1st order, inductor only crossover.
Hi Galu.
The new UT603 meter arrived.
I've used it to test capacitors and it's displaying readings as expected.
I'll next wrap my head around measuring Inductance.
You mentioned that an Inductor can be measured successfully with one of its leads disconnected from a crossover circuit.
Does it matter which end is disconnected.
I was hoping to minimize any surgery. 👍
🙂
Hi Galu.
I disconnected each Inductor from the crossover circuitry on one side.
The Air Core Inductor measured 0.31mH.
The Iron Core Inductor measured 1.72mH.
I have a number of spare Inductors which I harvested from a couple of crossovers I salvaged.
I have pairs with readings as follows:
2 x Iron Core Inductors @ 0.89mH
2 x Iron Core Inductors @ 0.62mH
2 x Iron Core Inductors @ 3.84mH
2 x Air Core Inductors @ 1.22mH
2 x Air Core Inductors @ 0.24mH
Doubling 1.72mH gives a value of 3.44mH
Using the 3.84 Iron Core Inductors in place of the existing 1.72 Iron Core results in 0.4mH over.
Using both the 1.22mH, & 0.24mH Air Core Inductors to supplement the existing 1.72 Iron Core results in 318mH which is .26mH under.
What are your thoughts?
I can't hear how the speakers sound, Cliff, so can't say for certain that doubling the bass inductor value will be a positive act.
What I can say is that a 10 to 20% difference from the targeted inductor value will make no audible difference in such a simple crossover.
For example, if the target value is 3.44 mH, then 0.4 mH over represents a percentage difference of (0.4/3.44 x 100)% = 11.6%, which is good enough.
Why fret over such a small discrepancy when you intend to make such a large change in inductor value?
Who knows what value of inductor will give the best result with these new woofers? You can but experiment with different values of woofer inductor or even with no inductor at all!
What I can say is that a 10 to 20% difference from the targeted inductor value will make no audible difference in such a simple crossover.
For example, if the target value is 3.44 mH, then 0.4 mH over represents a percentage difference of (0.4/3.44 x 100)% = 11.6%, which is good enough.
Why fret over such a small discrepancy when you intend to make such a large change in inductor value?
Who knows what value of inductor will give the best result with these new woofers? You can but experiment with different values of woofer inductor or even with no inductor at all!
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Thanks Galu.
I'll do some experimentation and lock down with solder until I achieve best result. 🙂
👍