AR.com DIY Speaker Modifications

[dave_bullet]

And I'm hoping the addition of a 5 ohm resistor to each speaker will tame the tweeter a bit and correct the sibilance.

Freeshipping - I've attached a photo showing how I attached the resistor (madisound supplied PCB & xover). Note I've soldered it. I'm happy with this as I am comfortable unsoldering if needed - but I prefer the AR.coms with this setup. I recommend as others have to use aligator clips (as long as they securely attach! - don't want a short blowing your output stage on your amp!) Atleast with soldering - you "know" no stray wires will come loose when you put the xover back into the cabinet. To me it is more important to protect my amp.

anyway... My xover as shown has the 5 ohm resistor (at the back covered by some polyfill). I unsoldered the 2 ohm resistor and added another one to the end (as shown) then re-attached the new resistor to where the old 2 ohm resistor terminated (at the bottom) - you can see the tweeter +ve wire also (I've marked it all so it will be pretty straight forward.

If you do not want to unsolder the original 2 ohm resistor on the madisound board - you could simply put the resistor on the wire between the board and tweeter itself - which is what the others and Ed originally recommend. I just have a personal preference to solder and put xover components on the board.

David.

[dave_bullet]

I've attached 3 images showing the simulated response by using 2 ohms (standard), 4 ohms and 6 ohms to pad the tweeter - so you can see how it shapes the treble response.

As you can see, an increase in 2 ohms = about a 1dB cut. the hump from 2.7 - 4.5KHz is caused by the breakup mode of the woofer.

David.

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I've attached 3 images showing the simulated response by using 2 ohms (standard), 4 ohms and 6 ohms to pad the tweeter - so you can see how it shapes the treble response.

As you can see, an increase in 2 ohms = about a 1dB cut. the hump from 2.7 - 4.5KHz is caused by the breakup mode of the woofer.

David.

Thanks for the graphs. So the 2 ohm graph is of the crossover without the addition of any other resistors? And, the 4 ohm graph shows the results when a 2 ohm resistor is added to the existing 2 ohm resistor on the crossover board?

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If you do not want to unsolder the original 2 ohm resistor on the madisound board - you could simply put the resistor on the wire between the board and tweeter itself - which is what the others and Ed originally recommend. I just have a personal preference to solder and put xover components on the board.

David, thanks for the photos and explanation, big help. I too would prefer to solder the resistors to the crossovers, however I have no interest in learning how to desolder so I will be using alligator clips. I see from your photo the alligator clip attaches to the speaker wire that runs from the tweeter to the positive tweeter terninal on the crossover. So, I will attach the alligator clip to either end of this wire where it has been striped bare.

How do I attach the resistor to the alligator clip? Do I just fold the 2 wires from the ends of the resistor together and put them inside the end of the alligator clip?

Also, from your photo I see you added a 2 ohm resistor to the existing 2 ohm resistor on the crossover board for a total of 4 ohms. So would this total of 4 ohms produce the results showing in your graph for 4 ohms, or would it be graphed as 2 ohms since you added a 2 ohm resistor? Thanks

[dave_bullet]

David, thanks for the photos and explanation, big help. I too would prefer to solder the resistors to the crossovers, however I have no interest in learning how to desolder so I will be using alligator clips. I see from your photo the alligator clip attaches to the speaker wire that runs from the tweeter to the positive tweeter terninal on the crossover. So, I will attach the alligator clip to either end of this wire where it has been striped bare.

You are correct

[QUOTE=How do I attach the resistor to the alligator clip? Do I just fold the 2 wires from the ends of the resistor together and put them inside the end of the alligator clip?[/QUOTE]
If it were me, I'd do the following

PCB tweeter +ve terminal <-> solder a length of wire and crimp an alligator clip <-> teeth of clip onto resistor <-> resistor <-> teeth of second clip and crimp on some wire <-> solder wire to +ve terminal of tweeter

That way - you have an alligator clip off the PCB and one off the tweeter - so you can replace components in between without any soldering. If you want to remove the extra resistor - just get the alligator clips to bite onto eachother

[QUOTE=Also, from your photo I see you added a 2 ohm resistor to the existing 2 ohm resistor on the crossover board for a total of 4 ohms. So would this total of 4 ohms produce the results showing in your graph for 4 ohms, or would it be graphed as 2 ohms since you added a 2 ohm resistor? Thanks[/QUOTE]
Your first point is correct. The total is 4 ohms on the board so that relates to the 4 ohm graph. The 2 ohm graph is the standard board shipped by madisound with only one 2 ohm resistor.

Let me know how you go...
Cheers,
Dave.

[dave_bullet]

Sorry - I stuffed up the quoting of your questions. You'll need to read my response in the quoted section above

Cheers,
Dave.

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dave_bullet,

I'd like to wire the resistor as you suggested in the following. Would I do this in place of the existing wire between the PCB tweeter + terminal and the tweeter's terminal, or are you suggesting I do this in addition to the existing wire that runs between these two points? Thanks

"PCB tweeter +ve terminal <-> solder a length of wire and crimp an alligator clip <-> teeth of clip onto resistor <-> resistor <-> teeth of second clip and crimp on some wire <-> solder wire to +ve terminal of tweeter"

[dave_bullet]

If you have one piece of wire already between the PCB +ve and Tweeter +ve, then you just use that - but unsolder (or unclip - however you've attached it) at one end. This becomes *EITHER* the PCB end of wire *OR* tweeter end of wire in my

"PCB tweeter +ve terminal <-> solder a length of wire and crimp an alligator clip <-> teeth of clip onto resistor <-> resistor <-> teeth of second clip and crimp on some wire <-> solder wire to +ve terminal of tweeter"

explanation as underlined above.

I hope that helps

Cheers,
DAvid.

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If you have one piece of wire already between the PCB +ve and Tweeter +ve, then you just use that - but unsolder (or unclip - however you've attached it) at one end. This becomes *EITHER* the PCB end of wire *OR* tweeter end of wire in my

"PCB tweeter +ve terminal <-> solder a length of wire and crimp an alligator clip <-> teeth of clip onto resistor <-> resistor <-> teeth of second clip and crimp on some wire <-> solder wire to +ve terminal of tweeter"

David,
Yes, I already have a wire soldered between the PCB tweeter + terminal and the + terminal of the tweeter. This is a wire I soldered per the Madisound instructions. Although I'm certain I understand your explanation, I don't see the need to desolder at either end of this wire. It seems all I need to do is cut the existing wire in the middle, strip the two new ends bare, crimp the alligator clips to these ends, and attach a resistor between the alligator clips. This is how I plan to proceed unless I'm advised there's something wrong with doing it this way. I expect to complete this mod and add the acousta-stuff later tonight. I will report my findings later this weekend. Thanks for all your help.

[bcass]

David,
Yes, I already have a wire soldered between the PCB tweeter + terminal and the + terminal of the tweeter. This is a wire I soldered per the Madisound instructions. Although I'm certain I understand your explanation, I don't see the need to desolder at either end of this wire. It seems all I need to do is cut the existing wire in the middle, strip the two new ends bare, crimp the alligator clips to these ends, and attach a resistor between the alligator clips. This is how I plan to proceed unless I'm advised there's something wrong with doing it this way. I expect to complete this mod and add the acousta-stuff later tonight. I will report my findings later this weekend. Thanks for all your help.

How about an L-Pad or whatever that variable resistor is called? Is there such a thing that you can wire between the PCB and the tweeter and then mount through the cabinet? My old Verit Heritage speakers have this on the front under the tweeter. I don't know what the Ohm range is, but maybe I could use this instead of swapping different resistors in and out.

Bryan