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How good is the crossover in your loudspeakers?

 

I just watched a Danny Richie YouTube video from three weeks ago (linked below). Danny is the owner/designer of GR Research, a company that caters to the DIY loudspeaker community. He designs and sells kits that contain the drivers and crossover schematics to his loudspeakers, to hi-fi enthusiasts who are willing and able to build their own enclosures (though he also has a few cabinet makers who will do it for you if you are willing to pay them to do so).

Danny has also designed crossovers for loudspeaker companies who lack his crossover design knowledge. In addition, he offers a service to consumers who, while liking some aspects of the sound of their loudspeakers, find some degree of fault in those loudspeakers, faults Danny offers to try to eliminate. Send Danny one of your loudspeakers, and he will free of charge do a complete evaluation of it's design. If his evaluation reveals design faults (almost always crossover related) he is able to cure, he offers a crossover upgrade kit as a product.

Some make the case that Danny will of course find fault in the designs of others, in an attempt to sell you one of his loudspeaker kits. A reasonable accusation, were it not for the fact that---for instance---in this particular video (an examination of an Eggleston model) Danny makes Eggleston an offer to drop into the company headquarters and help them correct the glaring faults he found in the crossover design of the Eggleston loudspeaker a customer sent him.

Even if you are skeptical---ESPECIALLY if you are---why not give the video a viewing? Like the loudspeaker evaluation, it's free.

 

 

https://youtu.be/1wF-DEEXv64?si=tmd6JI3DFBq8GAjK&t=1

 

And for owners of other loudspeakers, there are a number of other GR Research videos in which other models are evaluated. 

 

 

bdp24
jtgofish's avatar
jtgofish
517 posts
 

I have restored a lot of speakers in my time including refurbishing crossovers. At times I have had 3 or 4 speakers of the same make and model all with quite different capacitor values due to varying degrees of aging and natural variability.

Unless the values are way off [and I mean WAY off-like 50%out of value] they all sound much the same.That has surprised me.I have had to conclude that a fair degree of the sound relates to the drivers independent of what crossover components or values might be used.You certainly hear when drivers are not working properly.

toddalin's avatar
toddalin
469 posts
 

How good are my crossovers?  There are probably no others in the world that function as these do using these components and the parts selection has taken years of tweaking.

 

Caps were mixed for there "particular sound" and multiple values were mixed to as to produce the most common value (e.g., the higher of the two was always mixed with the lower of the two other caps when used in parallel).

 

devinplombier
856 posts
 

@toddalin 

It looks like VR1's wiper is floating, essentially making it a 50R fixed resistor?  Normally a L-pad wired as a variable resistor has ground (pin 3) floating. I'm probably not reading this schematics correctly.

kennyc
2,059 posts
 

I find myself on the fence regarding modifying crossovers.

One on hand, I purchased them for their sonic character so I’m resistant to change.   On the other hand, I’m open to changes of certain speaker crossovers like Magnepan and Klipsch - maybe it’s because the outcome is more positively predictable by following the footsteps of others.

toddalin's avatar
toddalin
469 posts
 

On an Lpad, there are two floating wipers, but only one is shown in the schematics.  We are using the other and it goes from ~11 to ~36 ohms before it opens completely.  The circuit works best above ~18 ohms, hence R2, with ~20 ohms being near optimal.

If you saw the frequency response of the JBL 2251J, the circuit would make more sense.

I want to roll it off at about 2,500 Hz but that peak at ~3kHz makes this near impossible to do cleanly.  I had to come up with some very imaginative thinking and a bit of luck from experimentation to make this work!

What I do is to roll it off a bit earlier by "over capacitating" it.  If you use too much capacitance in a second order low pass filter, you will greatly increase the slope but also  create a hump just below the roll off point.  The more capacitance, the bigger and lower the hump.  The shape of the rising hump is obvious with the Lpad is turned full up (open).

But I also let some of the signal pass through R1 or R2/VR1.  This portion of the signal is NOT IN PHASE with the hump and the more you let through, the lower the hump becomes until you have a fairly smooth response up to the ~2,500 Hz roll off point.  VR1 lets you selectively tune the hump.

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