Should I modify my existing crossovers?

Hi, I own a pair of ADS L1590/2 speakers. These speakers sound nearly perfect, except for a little mid-bass boom. There is an "Umm" sound in the male voice, which is a little bit annoying to me.

The low-pass filters on the woofers are pure second-order, without any other circuits, consisting of a 3.5 mH and a 100 uF capacitor. I have a 4 mH coil and a 130 uF cap for spare parts. I'm thinking of modifying the crossovers by using these components.

Then, I tried simulation on the old and new crossovers, and there were no problems with the results at all—smooth frequency responses and impedance curves.

However, my friend suggested to me that, in the second-order filters, the inductor value should not exceed the driver's impedance, which here is 3.8 ohms. So, I wonder whether his statement is true. Anyone could confirm, please?
 
Last edited:
diyAudio Moderator
Joined 2008
Paid Member
I would not change the crossover unless you can be sure there is a problem, or you are testing a hypothesis.

Otherwise, use an equaliser and room positioning and treatment to do your tuning. Also, perhaps try multi-subs for your bass.
 
  • Like
Reactions: 1 user
I would not change the crossover unless you can be sure there is a problem, or you are testing a hypothesis.

Otherwise, use an equaliser and room positioning and treatment to do your tuning. Also, perhaps try multi-subs for your bass.
I forgot to mention on the first post that the L1590/2 speakers have bypass switches for the woofer section. They were designed to be bi-amped.

I'm thinking to continue, but, I'm not sure if the statement of my friend is true? Can you confirm this?
 

Attachments

  • H21666-L280500870_original.jpg
    H21666-L280500870_original.jpg
    855.8 KB · Views: 40
  • s-l1600.jpg
    s-l1600.jpg
    262.3 KB · Views: 42
I am not sure I understand the reason for saying this. Maybe there is more information?
He explained that if the coil value is higher than the driver's impedance, there will probably be coil saturation.

In other words, for example, if the driver's impedance is 4 ohms, the inductor shouldn't be greater than 4 mH. Or if the driver's impedance is 8 ohms, the inductor shouldn't be greater than 8 mH.
 
diyAudio Moderator
Joined 2008
Paid Member
I'm not completely satisfied with that idea. Coil saturation is the result of an iron core becoming significantly magnetised. You could use an air core coil for no saturation, or there is a choice of sizes and permeabilities.
 
  • Like
Reactions: 1 users
Hi all,
yeah I would play with EQ to find it.

It could be bad crossover, but it could also be how your speaker interacts with the room. Or issue with the box, noise from a port if there is one, or standing wave within the box, or box walls radiating sound, probably combination of multiple things. Changing the coil might help it, or not. Try it :)
 
Last edited:
  • Like
Reactions: 1 user
Sorry, I don't understand if it's associated with the question. :)
in speakers, everything is associated!

Regarding those ADS speakers, they're so Eighties! I lived with a 10" during my youth, and a single 10" ( 2 in stereo!) is more than enough.
I initially thought that these woofers were 16 Ω by reading the impedance of the speaker system -8 Ω. But the values of the LC net seem to follow the 4Ω impedance, so the amplifier would put much power in those woofers, and those are big!.
I'd suggest...nahhh...never mind
 
  • Like
Reactions: 1 user
Hi all,
yeah I would play with EQ to find it.

It could be bad crossover, but it could also be how your speaker interacts with the room. Or issue with the box, noise from a port if there is one, or standing wave within the box, or box walls radiating sound, probably combination of multiple things. Changing the coil might help it, or not. Try it :)
Yes, I have read the review of the L1590/2s on the internet: https://www.audioasylum.com/reviews/Speakers/ADS/L1590-2/speakers/32/322122.html.

The reviewer said they have a lot of “cabinet talk”. I think I agree with him.

This led me to the assumption of lowering the crossover of the woofers, so that it might relieve the duties of the woofers. Hence, eliminate or alleviate the “Umm” sound in male voice. However, I’m still uncertain.

What do all of you think whether my assumption will provide the satisfied solution?
 
Hi,

yeah the crossover is part of the issue and it could help to tune the system, but if the walls talk they would still do :) You could try the EQ trick, try and see if you get the characteristic sound reduced with EQ. Then figure out if its something you could implement as part of the crossover.

If its the box though, you might be better to add bracing to the cabinet. Perhaps add constrained layer damping if you wish. And then see if the crossover requires work. You might be able to temporarily test this by clamping the box outside to add some tension to the walls.

In addition add some bracing you could add some "tiles" inside walls of the box that fit through woofer holes, perhaps of MDF or ply or something, can be quite thin I think. Glue to walls with viscoelastic glue to make sort of a CLD structure. Effectivity of this could be quite good, if successfully implemented. You might want to read on it, find suitable glue and think about it. Perhaps even CLD bracing :)
 
Last edited:
  • Like
Reactions: 1 user
@presscot , I‘m starting to think they voiced the whole line of speakers purposely with that upper bass resonance. Why? Maybe to lend more impact to male vocals…….its just conjecture/conspiracy theory on my part, but I do recall some of that time period manufacturing had intentional cabinet resonance as part of the voicing.
I ended up fixing it with a gallon of paint atop each speaker, wife says thats got to go! https://www.diyaudio.com/community/threads/ads-l880-2-rebuild.396121/

I Will probably put some bracing in the box one day or another. You should try some cross braces.

tmuikku, you posted while i was typing, its funny you mention cld as I was considering wrapping the whole box with a new box (carpet glue between) as mine are black vinyl and not perfect condition.
 
  • Like
Reactions: 1 users
Here is the demonstrating video.

I played a Chinese song. The singer is female—Teresa Teng.

As can be heard, despite the female voice, there was still “Umm” sound in the low vocal notes.

Anyway, I used to find some people applied the “damping material” for use in car audio; the door damping, on the cabinet walls of the L1590/2s. However, I think using bi-amping function and changing the crossover there is easier than damping the walls. So, I would try this first, and if it doesn’t work, I’ll try damping and bracing next.
 

Attachments

  • IMG_6399.mp4
    8.6 MB
Yes, reducing capacitor will make less bump at the corner frequency. But, reducing the cap alone will result in moving the corner frequency higher as well, AFAIK.

So, in order to move corner frequency lower, I should enlarge both capacitor and coil, and that I already have the larger ones as spare parts.

However, I agree with you it’s the boxes that sing.
 
  • Like
Reactions: 1 user
Well, if you make to have access to all of the speakers terminal...
And you are confident that any change could bring tò damage, from simple shorts to amplifier destruction etc (Z Is important as It could cause some excess currents flowing) etc. Some changes mi ght be -:)- to try
Like...
Series connection of the woofers, with One having a cap across its terminals ( si mple series crossover)
Or adding a cone MW...;)
 
  • Like
Reactions: 1 user