I’ve been attempting to voicing my commercial speakers; ADS L1590/2, by eliminating some excessive mid-bass. The crossover between the dual 10” woofers and a 2” dome midrange is published at 350Hz with second-order slope for both high and low pass. What I have performed was lowering the woofers crossover frequency. Yes, it introduced more gap between two drivers. Yet, it’s fruitless, the problem still remains. Still, no space between midrange and bass was heard, but a little clearer midrange which is favorable and acceptable.
By the way, the original low-pass filter for the woofers is compose of a 3.5mH coil and a 100uF cap. I altered it to a 4.2mH coil and a 150uF cap. The high-pass filter for the midrange was left untouched consisting of a 2.6mH and a 33uF. Please forgive me for didn’t take a measurement because the speaker is about 42kg heavy. Nevertheless, trust my ear there’s a problem at mid-bass region, an Umm sound along with male’s voice and some upper bass boom.
I’m unsure whether that mid-bass comes from “upper frequency of the woofer” or the “cabinet talk”. However, as described above, I’ve done something to the woofer.
Consequently, I’d like to request for advices. What should I do next, without measurements? As far as I can think:
A) continue lowering the crossover point of the woofers’ low-pass filter
B) modify the cabinets, my friend suggested me to install the damping material for car’s doors to the cabinet walls.
By the way, the original low-pass filter for the woofers is compose of a 3.5mH coil and a 100uF cap. I altered it to a 4.2mH coil and a 150uF cap. The high-pass filter for the midrange was left untouched consisting of a 2.6mH and a 33uF. Please forgive me for didn’t take a measurement because the speaker is about 42kg heavy. Nevertheless, trust my ear there’s a problem at mid-bass region, an Umm sound along with male’s voice and some upper bass boom.
I’m unsure whether that mid-bass comes from “upper frequency of the woofer” or the “cabinet talk”. However, as described above, I’ve done something to the woofer.
Consequently, I’d like to request for advices. What should I do next, without measurements? As far as I can think:
A) continue lowering the crossover point of the woofers’ low-pass filter
B) modify the cabinets, my friend suggested me to install the damping material for car’s doors to the cabinet walls.
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Two problems with that approach.
1. It can upset the crossover itself and alter the power to response ratio.
2. Voicing can involve harmonics of where we assume we should be tweaking.
Both issues can be managed by putting the crossover back and using an equaliser.
1. It can upset the crossover itself and alter the power to response ratio.
2. Voicing can involve harmonics of where we assume we should be tweaking.
Both issues can be managed by putting the crossover back and using an equaliser.
Well, measurement would help immensely... before that you just need to do what ever you can to try and reason with it.
You could play multitone signal, touch the enclosure with your hand from various places, does it vibrate? Put your ear very close to various spots of the side / back panel, do you hear the panel make sound? You could use frequency sweep try and zone in to frequency area that seems exessive. If box noise seems plausible, you could use some ratchet straps or clamp outside the speaker try and dampen it and reduce walls vibration and see if it helps, and so on. If it got fixed you've found reason.
Did you try move the speaker further from room boundaries? If you happen to listen at modal null and speaker has some unfavorable positioning the bass could be missing which would make unbalanced sound. You could also try and arrange a null to the problematic bandwidth if it eases out some. Are the tweeters fine? It could be that the speaker frequency response is not extended enough and it just feels midrangy, are the tweeters fine? If everything is fine it's then crossover/voicing issue.
Hard to give proper advice with too much unknowns 🙂 If you measured the base, mid and tweet all separately, took impedance sweeps, you could diagnose it better and build the whole crossover from scratch if necessary.
You could play multitone signal, touch the enclosure with your hand from various places, does it vibrate? Put your ear very close to various spots of the side / back panel, do you hear the panel make sound? You could use frequency sweep try and zone in to frequency area that seems exessive. If box noise seems plausible, you could use some ratchet straps or clamp outside the speaker try and dampen it and reduce walls vibration and see if it helps, and so on. If it got fixed you've found reason.
Did you try move the speaker further from room boundaries? If you happen to listen at modal null and speaker has some unfavorable positioning the bass could be missing which would make unbalanced sound. You could also try and arrange a null to the problematic bandwidth if it eases out some. Are the tweeters fine? It could be that the speaker frequency response is not extended enough and it just feels midrangy, are the tweeters fine? If everything is fine it's then crossover/voicing issue.
Hard to give proper advice with too much unknowns 🙂 If you measured the base, mid and tweet all separately, took impedance sweeps, you could diagnose it better and build the whole crossover from scratch if necessary.
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If your speaker is not worth something like 20$ for a measuring microfone and a few minuites to learn how to use some free measuring program, it sure is not worth different parts in the x-over.
If I'm right you are talking about a ~40 year old speaker, which may suffer from any problem like hardened surrounds, dryed out ferro fluid and out of spec capacitors. Probaply all of them, not to mention possible "improvements" someone did before you started your modifications.
I don't understand how you want to correct problems you don't even know.
Anyway, I know these speakers well, heard them a lot even when they where new. People raving obout them may rather suffer from some nostalgic feelings than objectivity. Some called them neutral sounding, boring at any SPL may be a better description, even driven by high some powered amp. So you may search for something that has never been included in the design. Sound stage is nothing you can expect to be exceptional.
As a last remark: The elite developer tuning them at their time, sure squeezed the best that could be done out of the very simple chassis . Today you find much better chassis in the low end lines of Parts Express and other vendors for low $.
The 3-way, dome-dome-cone constructions where an industry standard at that time in Germany. It may not be an coincident they fell out of favor when the CD took over and moved into the basement in most homes. Where you still find many of them today, just like Braun, Heco, Canton etc.
The best you can do is to find a good, well know DIYS kit (this is speaker chassis with an x-over, as this is the most important and complicated part to get right!) that will fit inside the cabinet and sell the original speaker parts on eBay or the like, to someone who wants them as they are.
If I'm right you are talking about a ~40 year old speaker, which may suffer from any problem like hardened surrounds, dryed out ferro fluid and out of spec capacitors. Probaply all of them, not to mention possible "improvements" someone did before you started your modifications.
I don't understand how you want to correct problems you don't even know.
Anyway, I know these speakers well, heard them a lot even when they where new. People raving obout them may rather suffer from some nostalgic feelings than objectivity. Some called them neutral sounding, boring at any SPL may be a better description, even driven by high some powered amp. So you may search for something that has never been included in the design. Sound stage is nothing you can expect to be exceptional.
As a last remark: The elite developer tuning them at their time, sure squeezed the best that could be done out of the very simple chassis . Today you find much better chassis in the low end lines of Parts Express and other vendors for low $.
The 3-way, dome-dome-cone constructions where an industry standard at that time in Germany. It may not be an coincident they fell out of favor when the CD took over and moved into the basement in most homes. Where you still find many of them today, just like Braun, Heco, Canton etc.
The best you can do is to find a good, well know DIYS kit (this is speaker chassis with an x-over, as this is the most important and complicated part to get right!) that will fit inside the cabinet and sell the original speaker parts on eBay or the like, to someone who wants them as they are.
This sounds exactly like the problem I had with my L880’s. In my case it was a box resonance, and I disagree with turbo, these are pretty decent once sorted……certainly better than the cheapest crap PE sells.
Just to try, put something small and heavy (at least 5 kilos) on top of the box and try it, if it helps look at putting some cross bracing inside the box.
Just to try, put something small and heavy (at least 5 kilos) on top of the box and try it, if it helps look at putting some cross bracing inside the box.
How you rate a speaker is always a matter of taste and options for comparisons. Fixing a resonance that has been in a speaker for 40 years seems odd.
I just fear that many expect some magical sound from such a speaker. You will be disapointed and nothing will fix this.
To describe the construction, there are some very basic 10" low frequency driver in a closed volume, a 2" dome that has to work very hard down to 300 Hz and a small dome doing the sparkle. This is nothing very promising if you ask someone who has some experience. At least the very low x-over of the soft dome is a problem. These are better used from 600-800Hz. This, again, is to find a compromise the new problems of two large woofer run in parallel induce. It may boil down to cost, as it is too often the cause.
If the construction would have been a 3 1/2 way with just some additional parts, it might have been a better speaker.
Also, in most cases some decend mid woofer would have been better than using a modified version of the 2" dome type, but this would have lead to problems with the tweeter, which already had to be fused to keep up with the other chassis. These domes burned fast, any party was usually the end of one or two...
So, done right, this would have needed some heavy crossover coils for the second woofer at least, or best, an additional, small mid woofer with even more extra components in the crossover.
If such speakers are constructed, there are usually different options offered to the deciding people, prior to production. In most cases the cheapest one to build is choosen. It may sound rediculous, but often a few $ have to be saved on a 1200$ speaker, as the manager decides his customers "don't hear the difference any way". Sometimes improvements are even "saved" for the next generation model, so there is no cost for a new development.
Customers buy speaker because of reviews, brand image and design. The objective sound quality comes last.
There is something else to be thought of if we talk about the 80th. At this time in most cases a record player was the source. The pickup did decide how a record sounded. So this single component, not taken serious by many, changed the quality of a reproductive chain completely. The same speaker could sound dull or bright, just by using another pickup. So to some extend you did listen more to the record player than to the actual speaker.
This changed with the CD. It made any comparison of audio components much simpler and more reliable. The often fought about differences in CD-player sound are close to non exiting, if you compare them to differently priced pickups of the time. The so considered, high quality "standard" Shure pickup of that time was more expensive than many complete record players you could buy!
I just fear that many expect some magical sound from such a speaker. You will be disapointed and nothing will fix this.
To describe the construction, there are some very basic 10" low frequency driver in a closed volume, a 2" dome that has to work very hard down to 300 Hz and a small dome doing the sparkle. This is nothing very promising if you ask someone who has some experience. At least the very low x-over of the soft dome is a problem. These are better used from 600-800Hz. This, again, is to find a compromise the new problems of two large woofer run in parallel induce. It may boil down to cost, as it is too often the cause.
If the construction would have been a 3 1/2 way with just some additional parts, it might have been a better speaker.
Also, in most cases some decend mid woofer would have been better than using a modified version of the 2" dome type, but this would have lead to problems with the tweeter, which already had to be fused to keep up with the other chassis. These domes burned fast, any party was usually the end of one or two...
So, done right, this would have needed some heavy crossover coils for the second woofer at least, or best, an additional, small mid woofer with even more extra components in the crossover.
If such speakers are constructed, there are usually different options offered to the deciding people, prior to production. In most cases the cheapest one to build is choosen. It may sound rediculous, but often a few $ have to be saved on a 1200$ speaker, as the manager decides his customers "don't hear the difference any way". Sometimes improvements are even "saved" for the next generation model, so there is no cost for a new development.
Customers buy speaker because of reviews, brand image and design. The objective sound quality comes last.
There is something else to be thought of if we talk about the 80th. At this time in most cases a record player was the source. The pickup did decide how a record sounded. So this single component, not taken serious by many, changed the quality of a reproductive chain completely. The same speaker could sound dull or bright, just by using another pickup. So to some extend you did listen more to the record player than to the actual speaker.
This changed with the CD. It made any comparison of audio components much simpler and more reliable. The often fought about differences in CD-player sound are close to non exiting, if you compare them to differently priced pickups of the time. The so considered, high quality "standard" Shure pickup of that time was more expensive than many complete record players you could buy!
CD sound can vary a lot depending on how the original recording was made. Some hit the tape way too hard to make it loud for the radio, for example. Some other all digital music is intentionally clipped at mastering and made to sound very bright because all frequencies are being used to make it loud, instead of allowing the natural roll-off of HF that happens in musical instruments and voices.
I think you're going about this incorrectly given your description of what you are trying to chage. You may have more luck modifying the Q of the woofer filter also to change the shape of the knee in the crossover. If you do that correctly, you can impact the midrange less while suppressing some of the midbass/low midrange.
This model is using flat frequency response and impedance just to more clearly show the basic shapes.
Red line is 3.5 mH with 100 µF. Blue is 4.2 mH with 150 µF. The biggest difference is actually around 650 Hz.
In this one, the blue line is 5.1 mH with 68 µF.
Of course the integration between the woofers and midrange is impacted by this as well, so it's best to monitor with measurements how adjustments are actually affecting frequency response. Sometimes they do the opposite of what you plan because of how the drivers interact.
That region is fussy in general. It's a fine line between voices sounding too warm or too midrange prominent. Male speaking voices can help highlight it. Having a good reference speaker or set of headphones to immediately compare to can also help.
And as AllenB suggested, an equalizer is also handy. Even if you don't want to use it long term, it can help you figure out where the problem actually is, and find a way to address it with the passive crossover.
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I think you posted on DIY Audio facebook group too.
I'll add to my post there by saying, if you think the midrange and treble are impressive / good, then it is likely the designer did a good job on the woofer / midrange crossover already.
my focus would be on cabinet resonance, any leaks (esp. around driver mounting - may not sound like a hiss or chuff) and stuffing (depending on whether this is a ported design). Even if ported, keeping the stuffing away from the port to not interfere with operation will attenuate the midbass by maybe 1dB but may be worth it for the quality.
For others benefit - I suggested generating tones via WinISD or similar to try and find any resonant frequencies, then attempt to damp by clamping suspect panels for bracing benefit or damping material.
I'll add to my post there by saying, if you think the midrange and treble are impressive / good, then it is likely the designer did a good job on the woofer / midrange crossover already.
my focus would be on cabinet resonance, any leaks (esp. around driver mounting - may not sound like a hiss or chuff) and stuffing (depending on whether this is a ported design). Even if ported, keeping the stuffing away from the port to not interfere with operation will attenuate the midbass by maybe 1dB but may be worth it for the quality.
For others benefit - I suggested generating tones via WinISD or similar to try and find any resonant frequencies, then attempt to damp by clamping suspect panels for bracing benefit or damping material.
This is the best answer IMO. You could play from a computer with equaliser to test. If its good, add a hardware equaliser to the system. Or always play from computer.
Is the midrange enclosed? Keep woofer interactions away from the mid. Damping,etc
Driver magnet & or basket legs damping.
I've used silicone.
Driver magnet to frame-applied silicone in the gap.
Basket legs- applied silicone to wax paper strips & wrapped around basket legs , paper clip or staple-let dry(might take a few days-set, fumes, etc).
Some use plumbers putty but after time I've seen this stuff dryout.
Some use damping material strips.
etc.
Dave's Fastlane
https://web.archive.org/web/20140911011705/http://mysite.verizon.net/res12il11/id130.html
PE TechTalk
https://techtalk.parts-express.com/forum/tech-talk-forum/27929-damping-driver-baskets
Driver magnet & or basket legs damping.
I've used silicone.
Driver magnet to frame-applied silicone in the gap.
Basket legs- applied silicone to wax paper strips & wrapped around basket legs , paper clip or staple-let dry(might take a few days-set, fumes, etc).
Some use plumbers putty but after time I've seen this stuff dryout.
Some use damping material strips.
etc.
Dave's Fastlane
https://web.archive.org/web/20140911011705/http://mysite.verizon.net/res12il11/id130.html
PE TechTalk
https://techtalk.parts-express.com/forum/tech-talk-forum/27929-damping-driver-baskets
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From what I've read they tend towards boomy bass. Never have I ever heard a dome midrange that I liked, and they used that to get from the woofers to the tweeter. You might try reversing the phase of the mid and tweet, several combinations there. Possibly add stuffing and brace the cabinet better, if it isn't already.
Perhaps, you’ve already tried this, but something as simple as reversing the wire leads to the woofer pairs (or, alternatively, to the midrange driver), could significantly move the tonality in the direction you desire. I once owned a pair of Martin-Logan Sequel hybrid electrostatic speakers. There always was what, sounded, like a tonal depression, or unnatural lightness, in the crossover region between the dynamic woofer and the electrostatic panel upper range.
The simplest, and most easily undone step was to reverse the woofer lead wires. That change resulted in a much more natural sounding midrange tonality, and tonal coherence across the entire band of the speaker. It didn’t make the midrange bloated sounding, just noticeably less lightweight. I didn’t have any acoustic measuring equipment at that time, so I don’t know what the frequency or phase plots would have looked like before and after, so I won’t speculate on the manufactures original x-over design. I only know that it sounded more natural and that I never tired of the change, leaving the woofer leads reversed the remainder of the time I lived with those speakers. Without them drawing undue attention to the change each time I listened to music.
The simplest, and most easily undone step was to reverse the woofer lead wires. That change resulted in a much more natural sounding midrange tonality, and tonal coherence across the entire band of the speaker. It didn’t make the midrange bloated sounding, just noticeably less lightweight. I didn’t have any acoustic measuring equipment at that time, so I don’t know what the frequency or phase plots would have looked like before and after, so I won’t speculate on the manufactures original x-over design. I only know that it sounded more natural and that I never tired of the change, leaving the woofer leads reversed the remainder of the time I lived with those speakers. Without them drawing undue attention to the change each time I listened to music.
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I’d like to report the progress that I currently have successfully achieved the goal. Big thanks to @mattstat, I ended up with the 5mH and 70.5uF combination for low-pass of the woofers. The science is this combination yields a lower Q while remaining the same crossover point. As a result, the low Q gives “more control” to the woofers at their crossover region—here is the mid-bass region. The speakers are no longer have mid-bass boom. It reduces amplitude at the corner frequency about 3dB. Moreover, it allowed me to increase attenuations on mid and high further from previously 2dB to 3dB as well.
All in all, I got the new response curve matches to the original but have +3dB on the bass of lower than 100Hz region. I’m really satisfied with this result. It’s happy ending.
All in all, I got the new response curve matches to the original but have +3dB on the bass of lower than 100Hz region. I’m really satisfied with this result. It’s happy ending.
