Let us consider the typical two-way design of two speakers. The drivers are identical for speaker A and B. They are the same crossover point used. Speaker A uses Q at 0.707 on both drivers, the other uses Q at 0.49. Both speakers are measured flat frequency response. Will they have the different in sound?
They will differ on sound both objectively and subjectively.
Q=0.707 is a 2nd order Butterworth, Q=0.5 is a 2nd order Linkwitz-Riley alignment.
Even if the on-axis response is flat for both, the power response will differ because the different individual slopes, plus LR alignments are in-phase types, Bw alignments are not.
Q=0.707 is a 2nd order Butterworth, Q=0.5 is a 2nd order Linkwitz-Riley alignment.
Even if the on-axis response is flat for both, the power response will differ because the different individual slopes, plus LR alignments are in-phase types, Bw alignments are not.
For most smaller drive units the lower Q design will start rolling off at low frequencies earlier, so may well sound different with less measured bass. how you perceive these changes is the key.
If you want to know which one is better, that is tricky.
Room gain comes into play at these lower frequencies and if you want to use hard against a rear wall or in a corner you may have amble bass with a low Q design.
Can you model the response, and whilst changing box dimensions look at how the low frequency roll off changes it position. Also look at the excursion plots that can be interesting too as there is a trade off.
If you are using some really large woofer with a low resonant frequency already it may be harder to hear the difference.
If you want to know which one is better, that is tricky.
Room gain comes into play at these lower frequencies and if you want to use hard against a rear wall or in a corner you may have amble bass with a low Q design.
Can you model the response, and whilst changing box dimensions look at how the low frequency roll off changes it position. Also look at the excursion plots that can be interesting too as there is a trade off.
If you are using some really large woofer with a low resonant frequency already it may be harder to hear the difference.
This could produce multiple unrelated effects, spatial and time based making this a potentially unfair comparison.
Hi Allen! The man who like to speak mysteriously. 🙂
What is "this" in your answer which could produce multiple unrelated effects?
The question was that they would sound different or not.
The following was not a question but if this is an unfair comparison then which is better? If one is not obviously better than the other, than why the comparison is potentially unfair?
I think I know the answer, but asking for the OP.
YSDR, you are right, crossover Q not bass alignment Q.My mistake.
Differing crossover slopes will definitely sound subtly different. Both can definitely be good.
Differing crossover slopes will definitely sound subtly different. Both can definitely be good.
Au contraire YSDR, the reasons are in my previous post.
The traditional version of this question is a time based concern, for example uncertainties about ringing. presscot mentions the combined response is the same which implies a possible spatial variation.
The traditional version of this question is a time based concern, for example uncertainties about ringing. presscot mentions the combined response is the same which implies a possible spatial variation.
Let’s talk about the space between drivers at crossover point. If there is lower Q used, it should be wider bandwidth from cut-off frequency of each driver. And narrower bandwidth for the higher Q. Am I right? So, if they are both measured flat combined response, which one sound better?
Imagine trying to demonstrate what it feels like standing 1' below sea level, but not taking into account that your feet are now wet. Separate problems need to be isolated.
"Imagine trying to demonstrate what it feels like standing 1' below sea level, but not taking into account that your feet are now wet. Separate problems need to be isolated" I get what you're saying! Consequently, I need to improve my understanding. Not sure what to ask now. Xsim is like a Video game!
To be honest I was also uncertain which presscot meant, or whether neither in particular even. I could see the potential for confusion and I wanted to throw it out there.
It is not within the scope of XSim to consider either of the differences in question. Obviously the biggest potential difference is the response, and that was pinned down in the first post, clearing it from clouding the issue.
It is not within the scope of XSim to consider either of the differences in question. Obviously the biggest potential difference is the response, and that was pinned down in the first post, clearing it from clouding the issue.
I think it's stated that the ringing in higher Q filter cancels out in the sum, but I'm thinking that if drivers are not 100% in phase / time aligned, the ringing will not cancel out in the summed signal to the listener. Also off axis with divers at a distance from each other, the ringing would not cancel out fully?
Does this make sense?
Does this make sense?
@Rallyfinnen
What ringing cancellations are you talking about? In an another thread there was stated that if a ringing resonance peak was counteracted with a same Q filter then the ringing can cancels out if the phase/timing is spot on. Do you refer that?
This is another thing with the multiple drivers. We don't want any cancellations in the response, at least in optimal case.
What ringing cancellations are you talking about? In an another thread there was stated that if a ringing resonance peak was counteracted with a same Q filter then the ringing can cancels out if the phase/timing is spot on. Do you refer that?
This is another thing with the multiple drivers. We don't want any cancellations in the response, at least in optimal case.
An exception to this is that part of the response is made up acoustically. We sum at -6dB instead of -3dB.
A crossover is going to leave group delay.
A crossover is going to leave group delay.
Very theoretical...
With dsp-xo it is easy to create different topologies in presets and comparatively listen to them. Been there, done that, with a 4-way, 3-way and 2-way systems LR2 vs. LR4 acoustic or something like that. They do sound a little different and I prefer LR2 because it makes eg. violin to sound more natural. But with 2-way preference might be different because both drivers are working past comfort zones.
What is causing that? Like said earlier, many reasons of which I emphasize out of passband problems (resonances and directivity also vertically) and phase shift. It depends on application and specific driver units used which of these opposing factors gets major influence.
So, one must just try it and listen to carefuly!
With dsp-xo it is easy to create different topologies in presets and comparatively listen to them. Been there, done that, with a 4-way, 3-way and 2-way systems LR2 vs. LR4 acoustic or something like that. They do sound a little different and I prefer LR2 because it makes eg. violin to sound more natural. But with 2-way preference might be different because both drivers are working past comfort zones.
What is causing that? Like said earlier, many reasons of which I emphasize out of passband problems (resonances and directivity also vertically) and phase shift. It depends on application and specific driver units used which of these opposing factors gets major influence.
So, one must just try it and listen to carefuly!
As far as I can remember from school days a long time ago, a HP or LP filter has a time constant, and a Q that determines the damping/ringing. Higher Q, less damped/more ringing.
Combining 'mirrored' HP & LP filters (same XO frequency, Q and filter order) these ringings cancel out electrically. For example when the LP swings up, the HP swings down. Lets say you have a high Q XO, the tweeter and woofer would do this, but since they might not be time aligned, not ideal transducers, sitting at a distance from each other, this would probably create audible effects because the ringing is acoustically not canceled out 100%
So, lower Q, less risk of audible effects.
This is how I understand it, but I'm not saying I'm right..
Last edited: