Monitor RS6 - mods for a beginner

I have decided to take the plunge and make some modifications to my nine year-old Monitor RS6 speakers to tame the harshness. I am an absolute beginner but looking forward to the adventure! I will post pictures as I make the modifications.

I have removed the drivers, and attached is a picture of my crossover.

According to another post, the crossover has the following:
Tweeter: resistor =2.2, cap=6, coil = .25 in parallel
Mid: coil= .8 in series, cap= 4, coil =.25 in parallel
Woofer: coil =5.0 in series

I would love to hear from other owners who can recommend mods to tame the mid/high stridency. Are the mods made on the crossover circuit board or close to the drivers?

Thanks in advance!
 

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First start with investigating what is the problem. Take an equalizer and try to find the offending frequency range. Once you know what range sounds harsh, modify the crossover to make these frequencies less loud. You can do that by adjusting the values (ohms, millihenries, microfarads) of the crossover components. To get a better feeling what you should adjust, use Boxsim to model your crossover. For the drivers, pick similar Visaton drivers as they are already in the software. Then adjust component values (of the crossover) and see how the response changes. For example, harshness could be because there is too much power in the 5 kHz region (other reasons are also possible). Then you could try to adjust the components such that the 5 kHz region in your Boxsim simulation becomes a few dB lower.

Once you are satisfied, you could replace components by more expensive ones if you like. Opinions differ whether and to what degree this makes a difference.
 
I'd rewire everything by making all the paths anew; just substitute the rear panel with 6 binding posts - Or - there are 5-way binding posts for changing to some attenuation on the tweeter :confused:
However, nevermind :rolleyes:
So make the 3 (+3) speakers terminals available on the rear, and experiment ( just changing from internal to external ).
 
Erik this speaker has issues beyond the ability of a capacitor quality change to fix it. :D

http://www.diyaudio.com/forums/multi-way/115780-monitor-audio-s6-tweek-7.html

A 2.5 way with metal drivers. And an overly simplistic filter along these lines:

509336d1445048785-monitor-audio-s6-tweek-monitor-audio-s6.png


You really have to trace the circuit to know what is going on. Many versions of this speaker. It's not impossible that Monitor Audio have added a 6uF/0.2mH 4kHz notch shunt to the mid for instance. But I don't know. Looks like the above circuit, more or less.

It's a long and winding road to get rid of a harsh sound, but crossover improvements are key.

Here's where I am currently on my old MA R300-MD speakers.

599660d1487267698-restoring-monitor-audio-r300-bookshelf-speakers-monitor-audio-r300-md-resurrected-cabinet.jpg


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The original, harsh sounding MA300-MD filter is below. Along with a typical 6" SEAS metal bass driver's rather alarming harsh cone breakup, which is more apposite to this thread.
 

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I could add something. Back in the day, tone controls on amps really DID something. :D

I'm currently enjoying an ancient 30wpc Pioneer SX-450 receiver. You can totally control bass level with the tone control. And 2.5 ways have seriously loud bass, just how they work.

But the midrange issues need more crossover work here. As does the sound of a metal tweeter at the very top end. I can't recommend a Zobel (here 5W 7.5R and 0.68uF) on a metal tweeter enough. It works at many levels. Slight rolloff for one thing. But mainly an easy resistive 8 ohm load to the amp. An easy first mod.

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The midrange issues might be your next area to tackle. It's the hobby. How far do you want to go?
 

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And as for how much can you fix with a good cap, quite a bit methinks. Depends on what exactly the end user is perceiving. It's worth a try, depends on what the user is perceiving. My mods were cheap (<$20/speaker) and required little analysis. The same advice I've often given, with positive results.

Based on the measurements of course, I'd design a different crossover entirely. :) Maybe a little tricky as the tweeter needs to be measured off-axis to really assess the effect of that resonance, however I thought the cheap simple answer was the nicest way to start the OP off.

Best,

E
 
What you are really up against here is metal cone breakup.

For example:
E0018-08S W18E001
AL 170 - 8 Ohm

Joe D'appolito does a ca. 5kHz notch here:
THOR

Your woofers are an unknown quantity. But you ought to be able to roughly place the peak with sweepgen and the woofers directly connected to the amp, crossover bypassed. It's going to be between 4.5kHz and 6kHz for a 6 inch metal driver.
Audio Tools - from David Taylor, Edinburgh

Ideally you'd do some proper woofer measurements.

You then notch it about 5-10% higher, just how it works. The cap is going to be between 3.3uF and 6.2uF. So here's a 6.5kHz notch on the Visaton AL 170. I can't think of a better way to do it on a simple filter. Rough and ready? For sure. :)

Now I happen to have the components required lying about, so if it was my speaker, I would try this.
 

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I would love to hear from other owners who can recommend mods to tame the mid/high stridency. Are the mods made on the crossover circuit board or close to the drivers?

Thanks in advance!

Hello, this is easily modifed once you have the driver raw measurements in the box with a microphone at standard position 1 m from these. The problem is that measurements ought to be made by someone having these exact speakers, like yourself, and the procedure to do that would involve some work and inquiry on the topic. If you think you can do that, someone might suggest the proper alterations. This product is an ideal candidate for a modification. The tweeter/midwoofer response recorded at Stereophile is a proof of that. I'd even try to suppress the 20 kHz peaking, for the sake of pets.
 
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Lojzek is correct. It is the most complete, most no-holds barred way to get to a solution. :)

With the exception of room treatment. The speaker may sound unduly bright due to the room. As mentioned, I had similar and they didn't sound nearly as bad as that treble measurement would lead you to believe. Maybe throw pillows and blankets around the room first. :)


Best,

E
 
this is easily modifed once you have the driver raw measurements in the box

Well, that's quite optimistic. 2.5-way designs like Troels Gravesen's Peerless Nomex 164 or this Monitor Audio speaker actually are a big challenge even for a professional speaker designer IMO. Off axis response and phase matching with the tweeter is very tricky. And the tweeter of the RS6 is a nightmare. Of course you can flatten the response up to 10 kHz, but the dip at 15 kHz and the peak at 20 kHz is very hard to handle.

I do not post a crossover modification proposal, simply because I didn't find anything reasonable. Attached is a simulation of the original crossover, based on some assumptions and the measurements of stereophile.
 

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Nice work, Dissi.

601880d1488237747-monitor-rs6-mods-beginner-crossovermonitoraudiors6.jpg


If it's got a 5kHz notch on the mid, that is an improvement. I think this is the third schematic I've seen... does anyone ever actually look at their speaker, or do we just all rely in the web... :eek:

601555d1488119809-monitor-rs6-mods-beginner-img_1956.jpg


Hammond1, I think you need to check this. Because those small coils look different to me. But it is an atrocious tweeter, for sure. A SEAS would be better. H1212-06 27TBFC/G

That mid notch might be overly deep, and a small damping resistor might help, say, an ohm or two. I got the feeling the bass could do with some shunt element to take it down at 5kHz too.

MA did a few other things here:

509337d1445048785-monitor-audio-s6-tweek-monitor-audio-rs6-modified.jpg