How do you high pass your main speakers?

@mitch2 I suggest you read the original article. 

Thanks @perkri !

I paricularly think that audiophiles should focus on this sentence from Troels, which is in alignment with my previous statements:

But not having the midrange driver pumping deep bass has a positive impact on the midrange as well and it also relieves the power amplifier of some back-EMF coming from the speaker drivers. Pretty much a win-win situation.

While Troels is discussing a 3-way system with a dedicated midrange this is essentially the same as taking a 2-way and adding a subwoofer. High passing the satellite has enormous audible benefits that outweigh all of the puritanical nit picking by far.

There’s optimally and very very good, @mijostyn . :) I wager I can get to very very good, but rather than dicker in hypothetical arguments I’m going to put my money where my mouth is. I find that more convincing. :)

Yes, absolutely being able to control high and low pass is the easiest way to integrate a satellite and sub, but in many cases a user is specifically choosing a non-DSP based preamp and processor and hence my solution.  BTW, my solution is not unlike what Vandersteen does in some cases.  The Vandersteen solution is sound and mine is based on similar principles.

I’ll post back when I have got my project working. :)

@erik_squires , The only way eric that you can do what I have been talking about is with digital signal processing. The reason you have to have independent control over both high and low pass filters both 3 or 6 dB down points and slopes is because after matching time and phase the game is keeping the subwoofers out of the midrange and relieving the main speakers of as much bass as possible, two conflicting issues.

@mijostyn

First, weird that you can actually see how my name is spelled and still chose to misspell it.

Second, you are thinking too much like a speaker builder, which I am and respect, but it’s leaving you locked in your thinking. As speaker builders we think of the electro-acoustical properties of each driver and come up with a happy balance of slope, delay and phase matching, but if we are limited by what we can do in one filter section we can compensate for it in another. For instance, if your tweeter requires a steeper rolloff then you can compensate by removing a pole in the woofer.

This same principle also means that we can achieve very good frequency and phase matching if at least one of your filters (high or low) is one you have complete control over. So a simple high pass filter on the mains + DSP on the sub will work beautifully.

I’m working on a project right now to help demonstrate this more fully, I hope you find it helpful.

In any case, no matter how you chose to integrate a subwoofer, whether we use a DSP for both high and low pass filtering, use no high pass filter, or take the approach I suggest, taking in room measurements is essential. The basic speaker specs are practically useless in determining the appropriate filter settings once in an actual room.

In order to fine tune a subwoofer’s crossover you need to be able to select both frequency and slope of both the high pass and low pass filters independently.

Well.... kind of sort of but no... 😀

@mijostyn in an ideal world we could effectively turn a 2 way speaker system into a 3 way and apply the same amount of thought and flexibility to both the high and low pass filters and integrate a sub just like you would a driver in a speaker cabinet. I do actually favor this approach... but it’s not strictly required if the low pas filter section is flexible enough and lets us apply EQ and control the slope and delay. That is, we CAN get a little hack-y. with the method I suggested assuming I have a DSP to manage the subwoofer from and will achieve really good results.

I do agree that no matter what you do a delicate and fine tuned integration of the subwoofer is essential. After high-passing the mains the remaining issues are relatively minor and QED with good measurements and a DSP.

I keep meaning to do a blog post on exactly how this would work, so stay tuned gang! :) I will put my money where my mouth is and take lots of measurements.

Regarding the capacitor advice of @erik_squires: would it be possible to add it directly before the speakers? Of course, a different value would be needed. Sorry if this is stupid, I have no background in electronics. My reasoning is like this:

@donquichotte - Technically yes, but the cap size would be huge. It’s also not a very good or efficient idea. YG Acoustics has actually made a speaker like this, though really really not sure why, except maybe they were worried about over driving the woofer.

By putting a high pass filter before your amplifier you minimize the voltage swing the amp has to make, but putting it after means the amp still has to produce the same range of (+) and (-) voltages.

In other words, putting a high pass filter before your amp gives you more headroom, allowing it to play louder before reaching the limits

3. Or maybe this could be done inside the speaker, between the crossover and the woofer itself?

Well, yes, that’s called a crossover. 😂

Hey @bumpy48  - The value of the capacitor is based on the input impedance of your amplifier. 

You can use  this calculator, filling in the top with the input impedance (probably 25k or higher) and the Hz with the cut-off.  80 Hz is a good value there.

https://www.omnicalculator.com/physics/high-pass-filter

The cleanest way is a single capacitor around 80 Hz