Please help for Monitor Audio GS20 crossover tuning

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Hello guys!

This is my first post in loudspeakers forum but I have a very log experience with solid state amplifiers :)
I would like to ask you for advice regarding my speaker crossover upgrade.
The loudspeaker is Monitor Audio GS20 and it has the following crossover (please see the pictures below)
In you expert opinion, what can be improved here?

Thank you very much,
Mihai
 

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Is there some to change?
Don't you like the sound?
Components look to be appropriate and suitable.
A polypropylene cap in series, two polyester in parallel. A big iron core in series, just to knock down the coil resistance.
This kind of simple configuration doesn't cause a loss of sensitivity.
Monitor Audio is a serious make, in which way do you ask for a tweaking?
Do you want to change crossover frequencies? Orders? Slopes?
 
It' difficult to guess, without measuring or simulating.
It could be freq. peaks (drivers) or loudspeaker design (crossover), or both. As a blind shoot I would shunt the 1R at the mid crossover and test the difference. There was a thread ~1 year ago here @diy for the same problem, on another brand speaker. If it was only the tweeter I would add (and have on my Focals, really) a simple shoulder pad.
 
The first thing I would look at are the iron cored inductors, try to replace them with air cores with the same inductance / Rdc. This can give you some improvements especially when played loud.

Next up would be the capacitors, maybe some nice 400VDC poly's.

The last step would be to replace the resistors with MOX type resistors. Maybe try 1R5, 1R8, 2R2 to damp the tweeter a bit more since you indicated they where a bit "bright"
 
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The first thing I would look at are the iron cored inductors, try to replace them with air cores with the same inductance / Rdc. This can give you some improvements especially when played loud.

Next up would be the capacitors, maybe some nice 400VDC poly's.

The last step would be to replace the resistors with MOX type resistors. Maybe try 1R5, 1R8, 2R2 to damp the tweeter a bit more since you indicated they where a bit "bright"
@Mihai
Usually when you have an air core instead of the cored inductor, you can have a little more resistance, but I' not keen for that to solve the problem. It would affect the bass/lower bass instead. As I said on my first post, I doubt this is a component quality problem. It's obvious I agree with last paragraph, test and see.
 
Advice

@Mihai
Usually when you have an air core instead of the cored inductor, you can have a little more resistance, but I' not keen for that to solve the problem. It would affect the bass/lower bass instead. As I said on my first post, I doubt this is a component quality problem. It's obvious I agree with last paragraph, test and see.

Inductor is right. If high section is too bright you may add a bland resistor in series to the midrange or to the tweeter (1 ohm), and a stronger one in parallel (20 ohm) - (a L-pad network).
If this is the problem (hi section too bright), pls don't touch the cored inductor. It does not affect the extension of bass tones; on the contrary, using an air cored coil (which is in general better for sound quality, anyway), the certain result is to increase the resistance in series to the woofer of 0,5/1 ohm, making the situation worst (it would sound weaker).
In this case, the same value of the so-called hidden resistor (typical of the air-cored inductor), should be added (in series) to the tweeter and the midrange, making loudspeakers less efficient.
As I don't know the drivers specifications, I can't suggest whether to add even a RLC notch filter.
A Hallo from Italy
 
Another solution

Hi,
I've thought about a less invasive option, which does not envisage a crossover tweaking.
GS20s are double-ported speakers. Aren't them?
So, try to plug a port, but ONLY ONE.
Try with each one of them, until you feel the bass sounding deeper.
It could be a solution to mitigate the supremacy of treble tones.

P.S.: I don't know if they have in their interior two separate volumes, with a port in each chamber. It would likely make the operation fruitless.
Anyway you can try. It's a simple and less invasive solution, it could be worth of an attempt.
 
@Mihai
Usually when you have an air core instead of the cored inductor, you can have a little more resistance, but I' not keen for that to solve the problem. It would affect the bass/lower bass instead. As I said on my first post, I doubt this is a component quality problem. It's obvious I agree with last paragraph, test and see.

The idea behind this remark is that iron cored inductors can and will go into saturation when the system is played loud thus distorting the signal. Air core inductors don't suffer from this as the core can't be saturated. So this could be a tweak that improves the overall sound of your system.

Just my E0,02!
 
Hi,
I've thought about a less invasive option, which does not envisage a crossover tweaking.
GS20s are double-ported speakers. Aren't them?
So, try to plug a port, but ONLY ONE.
Try with each one of them, until you feel the bass sounding deeper.
It could be a solution to mitigate the supremacy of treble tones.

P.S.: I don't know if they have in their interior two separate volumes, with a port in each chamber. It would likely make the operation fruitless.
Anyway you can try. It's a simple and less invasive solution, it could be worth of an attempt.

I had tried plugging the upper port but didn't resolved the problem ... and yes, GS20 are double-ported speakers with separate cabinets for mid-highs and bass, each with their one BR port
 
Hmm, bright metal coned/domed Monitor Audio GS20 speakers getting a bit fatigueging?

An externally hosted image should be here but it was not working when we last tested it.


The nature of the beast really! When they breakup, they breakup horribly! ;)

Looks like the tweeters could be padded/attenuated a bit with wirewound resistors to get the rising high frequency impedance a bit better behaved and give your amp an easier life:

An externally hosted image should be here but it was not working when we last tested it.


The overall impedance must be pretty low, say around 4 ohms, so it would be useful to know the DC resistance of the drive units. Got a multimeter?
 
Well, that's nice that it comes apart so easily. Is that a 104mm diameter unit?

I'm guessing you have two roads to examine here. First is an L-Pad of wirewound 10W resistors. Say 1 ohm series and 20 ohm shunt across the tweeter. Keep track of polarity, btw.

Second is to replace the metal tweeter with a soft dome.

Say you have (guesses...) a metal SEAS 27TBFC:
Seas Prestige 27TBFC G H1212

A softdome SEAS 27TFFC would probably be fine:
Seas Prestige 27TFFC H881

Bit of a guess, but if you can identify the tweeter there is a third possibility, a Zobel across it for a SEAS of 0.05mH is about 6 ohms and 0.820uF. That can be good, but you probably still need some attenuation here. A zobel is a resistor and capacitor in series connected across a speakers terminals designed to correct and flatten impedance and does a bit of high frequency damping too.
 
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Thank you system7.

I know what a zobel is, but ... in order to put a zobel over the speaker one must know how the twitter will behave in frequency domain.
The MA twitter is not OEM, is their on design based on C-CAM technology. I think is hard to get specifications from them :)
Anyway ... I will try the L-Pad suggestion because it seems to be the easiest way to attenuate the highs.
Another possibility is to replace the serial capacitor with a better one. What do you think about?
 
It's the nature of most loudspeakers that they have a lot of boom and tizz and brightness. It sells, especially when comparing models in the showroom. :D

IMO, metal tweeters present some unpleasant resonant supersonic characteristics to amplifiers, as this frequency plot for a SEAS 27TBFC/G driver suggests:

An externally hosted image should be here but it was not working when we last tested it.


Compare with soft dome SEAS 27TFFC:
H0881-06 27TFFC

A bit of attenuation will help greatly in smoothing the supersonic load which gets nastily reactive, I reckon. See how it goes.
L-Pad (Driver Attenuation Circuit) Designer / Calculator

As for special patented technology, well, I think it's all just physics in the end. Most commercial designs are really quite rough and ready and kinda cheapish. "Dumbed Down" is my friends description. My own MA speakers claim proprietary drivers, but they are actually KEF and SEAS. :D

Swapping the tweeter capacitor for something more exotic is fun, but really won't address the brightness.
 
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Ports and L-Pad

I had tried plugging the upper port but didn't resolved the problem ... and yes, GS20 are double-ported speakers with separate cabinets for mid-highs and bass, each with their one BR port

As written before, if the first port is for bass section, but the second for mid-hi (they generally have a closed volume) you can't improve the situation.
The easier solution is, as abundantly written, a L-Pad network. Start with 1 ohm in series and 20 in parallel to the tweeter, at the end of crossover and close to driver poles... If it's not enough, increase to 1.56 in series and 18 in parallel, then 2.2 in series and 10 in parallel. You will have decreased tweeter sensitivity respectively of 2, 3 and 4db.
Try and don't exaggerate...
 
Hi,

As the alledged brightness extends lower down than the treble,
and the speakers appear to be 2.5 ways with the biwiring
splitting the 2 way and 0.5, try a 1R series resistor on
the 2 way section to warm up the balance somewhat.

don't worry about the 20R

rgds, sreten.

FWIW metal dome supersonic resonances do
not cause any problems for amplifiers at all.
That is incorrect technical conjecture.

The tweeter looks very like made for MA by Seas.
 
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