Lately I've been using a computer to develop crossovers and EQ for multi way speakers. It is very powerful, very easy to use, and allows lots of fine detailed control (and the software is very affordable!) - Reaper is an excellent place to start. It even includes the plugins one needs - REAPER | Audio Production Without Limits So I'm learning I have more and more possibilities when it comes to crossovers and able to reach more and more specific acoustic targets.
I'm considering moving my 3-way 'up' to 4-way, but this will require dropping a crossover smack in the middle of the midrange - somewhere around 700Hz. One of my top concerns is power response, second only to the on-axis frequency response.
JohnK has done some nice work on crossovers and their power response: Power Thanks John! What is obvious is that all crossovers introduce dips in the power response, some more, some less.
On the second page of the above link, John states his experience has been that LR2 crossovers have a more neutral presentation (compared to LR4), even though they have a larger dip in the power response. I've heard other people say the same.
Recently though, Floyd Toole published some research that may be comparable - although it may not be! He studied the minimum audibility of resonant peaks in a speaker's on-axis frequency response. The upshot was that lower Q peaks were audible at much lower levels compared to high Q peaks - aka, it took a much louder high-Q peak to be as audible as a low-Q peak. The reason this might be related to dips in power response is the different order crossovers look like they are changing the Q of the dip - with higher orders having much narrower dips - while not increasing their dB level. If the above study can be extrapolated to the power response, it would suggest that higher order crossovers should make the power response dips less audible.
Sure, the best crossover is no crossover, but assuming we have to drop one in at 700Hz, what crossover order/type do you think sounds most neutral?
If possible, lets keep the conditions more 'ideal' - there are no issues with acoustic centers, driver spacing, beaming, limited excursion, group delay nonlinearity, absolute polarity, etc (if possible). Also, 1st order slopes are not being considered. Sorry 😀
I'm considering moving my 3-way 'up' to 4-way, but this will require dropping a crossover smack in the middle of the midrange - somewhere around 700Hz. One of my top concerns is power response, second only to the on-axis frequency response.
JohnK has done some nice work on crossovers and their power response: Power Thanks John! What is obvious is that all crossovers introduce dips in the power response, some more, some less.
On the second page of the above link, John states his experience has been that LR2 crossovers have a more neutral presentation (compared to LR4), even though they have a larger dip in the power response. I've heard other people say the same.
Recently though, Floyd Toole published some research that may be comparable - although it may not be! He studied the minimum audibility of resonant peaks in a speaker's on-axis frequency response. The upshot was that lower Q peaks were audible at much lower levels compared to high Q peaks - aka, it took a much louder high-Q peak to be as audible as a low-Q peak. The reason this might be related to dips in power response is the different order crossovers look like they are changing the Q of the dip - with higher orders having much narrower dips - while not increasing their dB level. If the above study can be extrapolated to the power response, it would suggest that higher order crossovers should make the power response dips less audible.
Sure, the best crossover is no crossover, but assuming we have to drop one in at 700Hz, what crossover order/type do you think sounds most neutral?
If possible, lets keep the conditions more 'ideal' - there are no issues with acoustic centers, driver spacing, beaming, limited excursion, group delay nonlinearity, absolute polarity, etc (if possible). Also, 1st order slopes are not being considered. Sorry 😀
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There are too many other factors involved to be able to choose a specific topology... IMHO the best midrange XO is one that keeps the XO out of the 300-5k range.
dave
dave
I would say the best tweeter xo point is 300-500hz
If looking solely at the crossover, a 2way will always be the better one
Only reason to choose a 3way would be if you use much better drivers that doesnt work any other way, or because of other priorities
In a 4way its your complete crossover in relation to driver slopes that determine you xo points an component values
Nothing else matter in this respect
You cant just choose a crossover at will
It depends on ALL your drivers
And the acoustic slopes you can achieve
On bass I would suggest electrically 18db, but modified
The rest would electrically all be a mix of lowpass/6db with paralel RC and highpass 6db with paralel LR
You may need LCR on tweeter ressonance
Use series attenuation
Whether it works only depends on a lot of fidling back and forth
Its beyond doubt that fewer components will always sound better, as long as proper function is retained
So, a certain minimum of components will always be required
And I would never attempt such without correct physical driver phase allignment
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Maybe you guys could give a little more specifics on how you prioritize things? What factors do you look at, assuming you have to crossover somewhere?
Clearly, my priorities are on axis flatness, and off axis regularity (leading to flat power response). The reason for being of this poll is to hear how people feel about the dip in power response caused by different crossover topologies, but also what crossovers people consider 'neutral'. Details, please!
And for the non-Windows crowd, if you want to play with VST/LADSPA EQ plugins, here's a GNU way of doing things: LMMS - Linux MultiMedia Studio
Cheers!
Cheers!
To be honest, I dont know how or why it works
I only keep trying until it works
But stay clear away from anything that doesnt follow basic rules
I usually try to use a very simple and logical methodical approach to tell me if Im doing right or wrong
My 3ways ended up quite good, after 5-10 years of work
Now sold to a dear friend
I think this xo is up to date
I only keep trying until it works
But stay clear away from anything that doesnt follow basic rules
I usually try to use a very simple and logical methodical approach to tell me if Im doing right or wrong
My 3ways ended up quite good, after 5-10 years of work
Now sold to a dear friend
I think this xo is up to date
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I am no expert but all crossovers seem to do damage. Maybe the crossover type isn't the problem as much as the physical differences and separation of the drivers. As a note rises or falls it sweeps across two different sounding drivers in two different points in space, and across an electrical network with phase changes.
If Reaper allows flexible enough parametric EQ, you might consider trying a Deuland topology for a 3-way system. This is a topology that uses coupled parametric equations so that the entire 3-way system is defined by a single parameter which basically controls the midrange spread. The really interesting aspect of this is that all drivers are in-phase across the full bandwidth, and the system exhibits a single phase rotation making it similar to a LR2 2-way.
I realize this doesn't get you to your 4-way, but it is suggested from the perspective that it may not be the midrange xover by itself that is responsible for particular audible artifacts, but the overall system response. The Deuland seems to be unique in treating the entire system rather than the low-mid and mid-high xovers seperately. It's tough to realize passively, but with Reaper it may be possible to experiment with reasonably easily.
I realize this doesn't get you to your 4-way, but it is suggested from the perspective that it may not be the midrange xover by itself that is responsible for particular audible artifacts, but the overall system response. The Deuland seems to be unique in treating the entire system rather than the low-mid and mid-high xovers seperately. It's tough to realize passively, but with Reaper it may be possible to experiment with reasonably easily.
I'm interested in the Duelund crossovers, but I'm not enough of a math whiz to follow his writings. Reaper does allow very extensive parametric EQ though ...
And I agree, crossovers do damage - but the point is that hopefully you get more than you sacrifice by including another driver. I'm hoping to learn a little more about which crossover types people consider least problematic.
The heart of the issue for me is this - by including a fourth driver, I have the potential to get a smoother power response - except for the notch added by the crossover. So will the added smoothness be enough to compensate for the problems created elsewhere? Which crossover topology will be the least problematic? You see where I'm going.
And I agree, crossovers do damage - but the point is that hopefully you get more than you sacrifice by including another driver. I'm hoping to learn a little more about which crossover types people consider least problematic.
The heart of the issue for me is this - by including a fourth driver, I have the potential to get a smoother power response - except for the notch added by the crossover. So will the added smoothness be enough to compensate for the problems created elsewhere? Which crossover topology will be the least problematic? You see where I'm going.
I voted for B3 - cause it's the kind they used in those cool Hammond organs! 😛
Honestly, it seems the most transparent to me. But horses for courses. I don't always use it.
Honestly, it seems the most transparent to me. But horses for courses. I don't always use it.
When i worked as a roadie at uni, one of the bands had a B3... i remember 1 gig... no you can't go straight thru into the venue, you need to go in the back, thru the kitchen, up, down, narrow stairs, many corners, down up, and then back at the end... you get the idea. I think we had to do that one 3 times...
dave
The Duelund approach is interesting, but nothing earth shattering. It is a novel approach but does it really matter if the tweeter is in phase with the woofer when it is down 40 dB or more? Additionaly, the Duelund transfer functions must be implimented as acoustic targets as must all crossover transfer functions.
Haven't tried LR8 since I can't find a components list for the plug-in cards my crossovers use to determine the frequencies and slopes for an LR8 response.
I like first order (which is disqualified here), but found out of band distortion was unacceptable to my ears and vertical dispersion was not as good as I'd like for the drivers and SPLs I prefer. So I worked up a xover type that approximates a first order reasonably well in amplitude and phase up to 1.5-2x (0.667 - .5x) of the xover frequency then goes to a notch response. The xover amplitude response then will typically recover to -20 to -40db max before the final first order rolloff. At the frequency that this amplitude recovery occurs (typically 4-8x or 1/4 - 1/8x the xover frequency, the driver itself is usually rolled off by a similar amount so the sonic contribution of this is insignificant. The nice thing about the notch is that it can be set to very effectively cancel a driver breakup resonance peak for woofers (that you would otherwise need a much higher order xover to do) or minimize excursion for a tweeter. The overall effective out of band performance is subjectively somewhere between a second or third order filter. Another nice thing is that, like a regular first order xover, there is only one series component so the sonic degradation is minimized.
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